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Background: The natural history of Kaplan fiber (KF) injuries after acute primary anterior cruciate ligament (ACL) reconstruction (ACLR) remains unknown., Purpose/hypothesis: The purpose of this study was to evaluate the temporal change in the magnetic resonance imaging (MRI) appearance of the KF complex after acute primary ACLR. It was hypothesized that KF injuries would resolve with time., Study Design: Case series; Level of evidence, 4., Methods: A retrospective MRI analysis was conducted on 89 patients with ACL-injured knees to assess the change in the radiological appearance of KFs after primary ACLR. Patients who had undergone index MRI and ACLR within 90 days of the injury and further MRI at 9 months after surgery were included. Diagnostic criteria to identify radiological evidence of a KF injury and its subsequent resolution were applied, including the presence of high signal intensity on fluid-sensitive sequences, which is indicative of a pathological process radiologically. The proximity of KFs to the femoral cortical suspensory device (CSD) was noted on MRI scans and quantified in millimeters., Results: A KF injury was identified in 30.3% (27/89) of patients, with isolated high signal intensity observed in an additional 18.0% (16/89). At 9 months, MRI evidence of the reconstitution of the KF complex was found in 51.9% (14/27) of patients, with persistent discontinuity in the remaining patients (13/27). All patients (16/16) with isolated high signal intensity had complete resolution on repeat MRI scans. KF thickening was observed in 26.1% (12/46) of patients with previously healthy KFs and in 25.0% (4/16) with isolated high signal intensity. The CSD was positioned in close proximity (≤6 mm) to the center of the KF attachment in 61.8% (55/89) of patients, and this was associated with increased rates of KF thickening., Conclusion: The KF injury resolved radiologically in over half of the patients at 9 months after acute primary ACLR. High signal intensity in the region of the KFs on index MRI scans resolved in all cases, with evidence of residual KF thickening in only one-quarter of cases on repeat MRI scans, equivalent to the rate in those with healthy KFs. As such, it is not advisable to use high signal intensity on preoperative MRI scans as the sole criterion for the diagnosis of a KF injury. The position of the CSD after ACLR was intimately related to the KF attachment in the majority of patients, which was associated with KF thickening on postoperative MRI scans.

Background: A paucity of information is available regarding the clinical outcomes of patients with radiological evidence of Kaplan fiber (KF) injury who undergo anterior cruciate ligament (ACL) reconstruction (ACLR)., Purpose/hypothesis: The purpose was to compare clinical and functional outcomes in patients undergoing acute primary ACLR with and without magnetic resonance imaging (MRI) evidence of KF injury. The hypothesis was that there would be no difference in clinical or functional outcomes in patients with versus those without radiological evidence of KF injury., Study Design: Cohort study; Level of evidence, 3., Methods: MRI analysis was conducted on patients in a longitudinal prospective study of ACL injury. Only patients who had an MRI scan and had undergone isolated primary ACLR within 60 days of injury were included. MRI was performed using standard knee protocols, and diagnostic criteria were applied to identify KF injury. A total of 32 patients with KF injury (mean age, 24.2 years; 21 male, 11 female) were identified and matched for sex, age, graft type, and preinjury activity with 90 patients who had intact KF. Patients were followed up at 12 months with KT-1000 arthrometer measurements of side-to-side difference in anterior knee laxity, single- and triple-hop limb symmetry index (LSI), Marx activity and International Knee Documentation Committee (IKDC) scores, and return to sport (RTS) rates at 12 months and 24 months., Results: No differences were found in anterior knee laxity and single- and triple-hop LSI values between the KF-intact and KF-injured cohorts at 12 months. No differences in Marx and IKDC scores were found between the groups at 12 months and 2 years. The overall rate of RTS within 24 months was 75% (92/122), and 5 patients (2 KF-injured; 3 KF-intact) had a subsequent graft rupture., Conclusion: We found no difference in clinical or functional outcomes in patients with and without radiological evidence of KF injury who underwent acute primary ACLR. Based on these findings, the radiological presence of KF injury at the time of acute ACL injury should not be regarded as a risk factor for a negative prognosis after ACLR.

Context: Psychological readiness to return to sport has been shown to be associated with future play after anterior cruciate ligament (ACL) reconstruction surgery but has not been extensively studied in adolescent athletes., Objective: To investigate the psychometric properties of the Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI) scale in adolescent athletes at multiple time points after ACL reconstruction surgery and determine whether psychological readiness scores at 6 months predict return to competition sport at 12 months., Design: Case series., Setting: Private orthopaedic clinic., Patients or Other Participants: A total of 115 adolescent athletes (65 girls, 50 boys) 17 years and younger who had undergone primary unilateral ACL reconstruction., Main Outcome Measure(s): The ACL-RSI scale was administered at 6 and 12 months after surgery, and return-to-sport status was also documented. Factor analysis was undertaken and predictive validity assessed using between-groups comparisons and receiver operating characteristic (ROC) curve statistics., Results: The ACL-RSI scores increased between 6 and 12 months (55 to 71; P < .001, effect size = 0.98). No floor or ceiling effects were present, and the scale had high internal consistency (Cronbach α at 6 months = 0.91 and at 12 months = 0.94). Principal component analysis showed that 2 factors were present: the first represented performance confidence and risk appraisal and the second, emotions. For the full-scale ACL-RSI, scores at 6 months had acceptable predictive ability for a return to play at 12 months (area under the ROC curve = 0.7, P = .03). When the 2 identified factors were analyzed separately, the emotions factor also had acceptable predictive ability (area under the ROC curve = 0.73, P = .009), but the confidence in performance and risk appraisal factors had poor predictive ability (area under the ROC curve = 0.59, P = .09)., Conclusions: Greater psychological readiness was associated with return to sport in adolescent athletes after ACL reconstruction, with the athletes' emotional response appearing to be more influential than their confidence in their performance or their appraisal of risk., (© by the National Athletic Trainers' Association, Inc.)

Background: Patient-reported outcome measures (PROMs) have become increasingly popular for assessing subjective elements of a patient's condition. Two frequently used knee-related PROMs after anterior cruciate ligament reconstruction (ACLR) surgery are the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) and the Knee injury and Osteoarthritis Outcome Score (KOOS). However, completing the full versions of both measures represents a considerable responder burden., Purpose: To compare a variety of KOOS short forms with each other as well as the IKDC-SKF in a large sample of ACLR patients between 2 and 6 years after surgery., Study Design: Cohort study (Diagnosis); Level of evidence, 2., Methods: The KOOS and IKDC-SKF were administered between 2 and 6 years (mean, 3 years) after ACLR surgery to a cohort of 832 patients (men, n = 489; women, n = 343). Two single-item assessment numerical evaluations were also completed for knee function and satisfaction. The following short form versions were calculated from the full KOOS: the KOOS-12 short form, KOOS-Physical Function Short form (KOOS-PS), KOOS-Joint Replacement Short form (KOOS-JR), and KOOS-Global. Descriptive statistics were calculated for all PROMs and associations between measures were explored using nonparametric (Spearman rho) correlations. Floor or ceiling effects were considered present if >15% of patients reported the worst (floor effect) or best (ceiling effect) possible score. Age and sex comparisons were also made for each PROM., Results: Ceiling effects were present for all KOOS short form versions. They were highly evident for the KOOS-JR and KOOS-PS (37%-44%), but they were only marginally above the threshold for the KOOS-12 and KOOS-Global (16%). The KOOS-12 and KOOS-Global had the highest correlation with the IKDC-SKF but only explained 58% to 59% of the variance in scores. The KOOS-12 and KOOS-Global were very highly correlated (ρ = 0.98). Only moderate correlations were seen between the single-item assessments and the IKDC-SKF or various KOOS short forms. There was a negligible association between patient age and PROM scores, but there was no significant sex difference for any of the PROMs., Conclusion: The IKDC-SKF together with either the KOOS-Global or KOOS-12 may provide a comprehensive range of knee-related PROMs with minimized responder burden at 2 to 6 years after ACLR.

Objective: The goal of the modified Ellison operation as a supplement to a conventional anterior cruciate ligament (ACL) reconstruction is to decrease anterolateral rotational instability of a knee joint after ACL rupture, to improve the stability and prevent ACL re-rupture., Indications: An ACL rupture with high risk of re-rupture (young age, high-performance sport, hyperlaxity, contralateral ACL rupture in history), increased subjective and objective anterolateral rotational instability of the knee after ACL rupture, ACL re-rupture., Contraindications: Gonarthrosis, additive instabilities (e.g. posterolateral, medial), non-anatomical ACL reconstruction with persistent instability, general contraindications to surgery (e.g. infections), chronic irritation of the knee joint., Surgical Technique: Supine position. Mark the typical landmarks. Incision from Gerdy's tubercle extending proximally along the iliotibial tract (ITT) to the lateral collateral ligament (approx. 5 cm). Incise the ITT in the line of its fibers about 10 mm anterior to its posterior border and continue the incision proximally to 5 mm proximal to the LCL. Make a parallel incision 10-12 mm anterior to the first incision. Use sharp subperiosteal dissection to elevate the strip of the ITT from Gerdy's tubercle. Secure the distal end of the ITT strip with a nonabsorbable suture (e.g. FiberWire No. 2, Arthrex, Naples, USA). Expose the LCL and pass the ITT strip deep to the LCL from proximal to distal and back to Gerdy's tubercle. Reattach the distal end of the strip of the ITT to its original position at Gerdy's tubercle with a bone anchor. The defect in the ITT can be closed with an absorbable suture (e.g. Vicryl, Ethicon, USA) in the proximal part. Layered closure., Postoperative Management: Knee brace for at least 6 weeks, movement limitation of 0‑0-90° for 6 weeks, 2 weeks 20 kg partial weight bearing., Results: A total of 36 patients (mean age 18.9 years) with a high risk of ACL re-rupture have been treated with ACL reconstruction and modified Ellison procedure. Follow-up over 2 years. Of the patients 35 returned to the previous sports level, 1 patient suffered a re-rupture, 2 patients had cyclops resection and 1 patient contralateral ACL rupture., (© 2021. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Purpose: To compare patient reported outcomes and functional knee recovery following anterior cruciate ligament (ACL) reconstruction using either a quadriceps tendon (QT) or hamstring tendon (HT) autograft., Methods: Thirty-five QT patients (age 20; range 15-34 years) participated in this study and were matched for gender, age and pre-injury activity level to 70 HT (age 20; range 15-32 years) patients. The following assessments were performed at 6 and 12 months post-operatively; standardized patient-reported outcome measures (IKDC, KOOS-QOL, ACL-RSI, Marx activity, anterior knee pain), knee range of motion (passive and active), anterior knee laxity, hop tests (single and triple crossover hop for distance), and isokinetic strength of the knee extensors and flexors. All dependent variables were analysed using a two-way mixed ANOVA model, with within (Time; 6 and 12 months) and between-subject (Graft; QT and HT) factors., Results: Patient reported outcome measures and hop performance improved between 6 and 12 months (p < 0.001), however no significant differences in either patient-reported outcomes or hop performance were found between the two grafts. Isokinetic strength testing showed both groups improved their peak knee extensor strength in the operated limb between 6 and 12 months (p < 0.001), but the QT group had significantly lower knee extensor strength symmetry at both time points compared to HT at 60 deg/s (p < 0.001) and 180 deg/s (p < 0.01). In contrast, the QT group had significantly greater knee flexor strength symmetry at both time points compared to HT at 60 deg/s (p < 0.01) and 180 deg/s (p = 0.01), but knee flexor strength limb symmetry did not significantly improve over time in either group., Conclusion: Recovery of knee function following either QT or HT ACL reconstruction continues between 6 and 12 months after surgery. However, knee extensor strength deficits in the QT group and knee flexor strength deficits in the HT persisted at 12 months. This may have implications for decisions regarding return to sport., Level of Evidence: III., (© 2021. European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA).)

Purpose: The psychological response to an Anterior Cruciate Ligament (ACL) injury is significant and can negatively impact return to sports outcomes. This study aimed to quantify the association between factors associated with return to sport using network analysis., Methods: 441 participants who underwent primary ACL reconstruction. The 12-item ACL Return to Sport after Injury (ACL-RSI) scale was administered to all participants 12 months after surgery. Three network analyses were used to quantify the adjusted correlations between the 12 items of the ACL-RSI scale, and to determine the centrality indices of each item (i.e., the degree of connection with other items in the network). Further subgroup network analyses were conducted for those who had (n = 115) and had not returned (n = 326) to their pre-injury level of sport., Results: The greatest adjusted correlation was between Q7 and Q9 (fear of re-injury and afraid of accidentally injuring knee) of the ACL-RSI (group 0.48 (95%CI [0.40 to 0.57])) across all three networks. The most important item in the network was Q12 (relaxed about sport) across all three networks. Individuals who did return to sport had greater Strength centrality for Q8 (confidence in knee, P = 0.014) compared to those who did not return to sport., Conclusion: Fear of re-injury and being relaxed about playing sport were the two most important nodes in the network models that describe the return to sport readiness. The importance of knee confidence at influencing psychological readiness was greater in athletes who did return to sport compared to those who did not. Our findings provide candidate therapeutic targets that could inform future interventions designed to optimize return to sport rates in athletes post ACL reconstruction., Competing Interests: The authors have declared that no competing interests exist.

Objectives: To investigate differences in lower extremity kinematics at initial ground contact between successful and unsuccessful single limb landings following anterior cruciate ligament (ACL) reconstruction., Design: Observational study., Setting: Controlled laboratory environment., Participants: 22 male participants (aged 17-40 years) who had undergone unilateral ACL reconstruction attended a single test session., Main Outcome Measures: Within-subjects comparisons was performed for pelvis, hip, knee and ankle kinematics using paired t-tests., Results: When unsuccessful at landing on the ACL reconstructed limb, participants had significantly increased knee flexion (P = 0.04) and reduced ankle plantarflexion (P = 0.03) compared to their successful landings. In contrast, when unsuccessful at landing on the unaffected limb, participants had significantly increased pelvic contralateral hitch (P < 0.01) and increased hip abduction (P < 0.01) compared to successful landings., Conclusion: Body position at the time of initial contact was different for landings that were successful compared to landings that were unsuccessful. These differences were limb-specific: altered position in sagittal plane preceded unsuccessful landings on the reconstructed limb whereas altered position in the coronal plane body position that preceded unsuccessful landings on the unaffected limb. These findings suggest that limb specific landing strategies may be required to improve athletes' performance following ACL reconstruction., Level of Evidence: IV., Competing Interests: Declaration of competing interest The authors listed on this manuscript certify that there are no conflicts of interest., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Purpose: Restoration of knee muscle strength is associated with better outcomes following anterior cruciate ligament (ACL) reconstruction, but little is known about the outcome of strength following quadriceps tendon autograft (QT) ACL reconstruction in relation to other graft types. The aim of this review was to evaluate strength outcomes of the knee extensors and knee flexors following QT ACL reconstruction compared to (1) the non-reconstructed contralateral limb and (2) alternative ACL graft types., Methods: Four electronic databases were searched up until 21st February 2020. Summary meta-analyses were performed comparing knee strength outcomes following QT ACL reconstruction to the contralateral limb by way of limb symmetry index (LSI). Comparative meta-analyses were performed comparing QT ACL reconstruction to alternative ACL grafts for the two most frequently reported strength outcome measures which were peak knee extensor torque LSI, and peak knee flexor torque LSI at the following post-operative periods: 3, 5-8, 9-15, 24, 36-60 months., Results: In total, 18 studies met the inclusion criteria. Knee strength outcomes of 952 QT ACL reconstructions were included and compared to either the contralateral limb or 1 of 4 alternative ACL graft types; 245 hamstring tendon autograft (HT), 143 patellar tendon autograft (PT), 45 quadriceps tendon allograft, and 21 tibialis anterior allograft. Knee extensor strength LSI following QT ACL reconstruction did not reach 90% even at 24 months post-operatively. Conversely, knee flexor strength LSI following QT ACL reconstruction exceeded 90% at the 9-15 months post-operative period. Knee extensor strength at 5-8 months following QT ACL reconstruction appears similar to PT but weaker than HT ACL reconstruction. In addition, peak knee flexor LSI was significantly greater at 5-8 months in QT ACL reconstruction patients compared to HT patients., Conclusion: The decision to utilize a QT graft for ACL reconstruction should include consideration of strength outcomes. Knee extensor strength recovery following QT ACL reconstruction appears not to be restored before 24 months., Level of Evidence: Level IV., (© 2020. European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA).)

Objective: Abnormal movement patterns have been shown during landing in patients who have undergone anterior cruciate ligament (ACL) reconstruction surgery. The purpose of this study was to investigate landing biomechanics over time in this patient group to determine whether asymmetry between limbs reduced with time and after a return to physical activity., Design: Prospective longitudinal study., Setting: Biomechanics laboratory., Participants: Fourteen patients who had undergone ACL reconstruction surgery., Main Outcome Measure: Single limb landing assessments were made at two time points; within the first year (mean of 10 months) and at 3 years (after patients had returned to sport) following ACL reconstruction. Three-dimensional motion analysis was used to record kinematic and kinetic variables, which were compared across time and limb using ANOVA models., Results: Most biomechanical variables showed little change over time except for the external knee adduction moment at the operated knee, which increased (effect size d = 0.5), but remained less than the contralateral side. In the sagittal plane, asymmetrical landing patterns were seen at both assessments. Patients landed with reduced knee flexion angles (effect size range 0.76-0.9) and moments (effect size range 0.56-0.9) compared to the uninjured limb and made compensations for this by increasing the hip flexion moment (effect size range d = 0.6-0.75)., Conclusions: Asymmetrical landing biomechanics persisted at three years after ACL reconstruction in athletes who returned to sporting activity. Long term implications of controlling the landing by increasing the hip moment are unknown and require further investigation., Competing Interests: Declaration of competing interest None., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Biomechanical studies have suggested that the Kaplan fibers (KFs) of the iliotibial band play a role in controlling anterolateral rotation of the knee. There is a paucity of clinical information on whether injury to the KF in the setting of anterior cruciate ligament (ACL) rupture contributes to increased rotatory laxity of the knee., Purpose/hypothesis: The purpose was to evaluate the association among radiological evidence of KF injury, intraoperative arthroscopic findings, and grade of pivot shift at the time of ACL reconstruction (ACLR). It was hypothesized that KF injury would be associated with increased injury to the lateral compartment of the knee and a higher grade of pivot shift., Study Design: Cohort study; Level of evidence, 3., Methods: A retrospective magnetic resonance imaging (MRI) analysis was conducted on 267 patients with ACL-injured knees who underwent primary ACLR. Patients who had MRI and surgery within 60 days of injury were included (mean age, 23.6 years); there were 158 (59.2%) male patients. MRI was performed using standard knee protocols, and diagnostic criteria were applied to identify KF injury. Associations were made among MRI findings, intraoperative findings, and grade of pivot shift with the patient examined under anesthesia at the time of ACLR. A comparison was made between patients with and without radiological evidence of KF injury., Results: The prevalence of KF injury was 17.6% (47/267 patients). Arthroscopic evidence of lateral meniscal injury was associated with KF injury (KF intact, 31%; KF injured, 55%; P = .010). The majority of patients in the intact and injured KF groups had a grade 2 pivot shift (75% and 70%, respectively). A minority had grade 3 pivot shift: 5% in the intact group versus 6.4% in the injured group. There was no association between radiological evidence of KF injury and pivot-shift grade ( P = .600)., Conclusion: In acute ACL injury, KF injuries were not very common (17.6%), and the rate of grade 3 pivot shift was low (5.2%). When present, KF injuries were not associated with a higher-grade pivot shift. However, there was an association between KF injury and lateral meniscal tears identified at the time of ACLR. The role of KFS in controlling anterolateral rotatory laxity in the acute ACL injury in the clinical setting may be less evident when compared with the biomechanical setting.

Objective: To determine if anterior cruciate ligament (ACL) reconstruction with a quadriceps tendon (QT) could achieve faster postoperative recovery compared with hamstring tendon (HT) ACL reconstruction., Methods: Thirty-seven QT patients were matched for gender, age and preinjury activity level with 74 HT patients. A 6-month postoperative assessment included standardised reported outcome measures: patient-reported outcome measures (PROMs) (International Knee Documentation Committee-subjective knee evaluation form, Knee injury and Osteoarthritis Outcome Score-knee related quality of life subscale, ACL-Return to Sport after Injury scale, Marx activity scale, anterior knee pain), range of motion (active, standing and passive), anterior knee laxity testing, hop tests (single and triple crossover hop for distance) and isokinetic strength testing of the knee extensors and flexors. T-tests or Mann Whitney U tests were used to compare data between groups., Results: There were no significant differences between the two groups for any of the PROMs. The HT group had reduced active and standing knee flexion range compared with the QT group (p<0.001). Isokinetic strength testing showed significant deficits in limb symmetry indices for both concentric hamstring peak torque at 60°/s (p<0.001) and 180°/s (p=0.01) in the HT group. There were significantly greater deficits in limb symmetry indices for concentric quadriceps peak torque at 60°/s (p<0.001) and 180°/s (p=0.001) in the QT group., Conclusion: The QT graft does not appear to offer a more rapid recovery in terms of knee symptoms or function which could have allowed for faster progression to the dynamic phases of rehabilitation., Level of Evidence: Level III., Competing Interests: Competing interests: None declared., (© International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine 2021. Re-use permitted under CC BY-NC. No commercial re-use. Published by BMJ.)

Background: Performance in strength and functional testing is important when considering return to sport after anterior cruciate ligament (ACL) reconstruction. Both knee extensor strength and the single-leg squat (SLS) have been used in this context., Purpose: To evaluate the relationship between knee extensor strength and SLS performance after primary ACL reconstruction., Study Design: Cohort study (Diagnosis); Level of evidence, 3., Methods: A prospective cohort of 100 patients was assessed 6 and 12 months after primary ACL reconstruction with a hamstring tendon autograft. Knee extensor peak torque was measured. Three sequential SLSs were performed, and the maximum flexion angle identified from frame-by-frame video analysis was used as the measure of squat performance. A limb symmetry index (LSI) was calculated and satisfactory performance defined as ≥90%., Results: Extensor mechanism strength deficits were seen in 75% of patients at 6 months and 57% at 12 months postoperatively. Mean extensor mechanism strength showed a large improvement between 6 and 12 months (123.6 vs 147.8 N·m, respectively; P < .001; Cohen d = 1.10), and while there was also a statistically significant improvement in the mean maximum flexion angle, the change was small (66.1° vs 68.1°, respectively; P = .011; Cohen d = 0.26). There was a weak positive correlation between knee extensor strength and the SLS maximum flexion angle at 6 months ( r = 0.342; P < .001) and 12 months ( r = 0.245; P = .014). An SLS LSI <90% was 80% specific and 35% sensitive for extensor mechanism weakness at 6 months and 79% specific and 18% sensitive at 12 months., Conclusion: Extensor mechanism strength deficits are common after ACL reconstruction but reduce between 6 and 12 months. The SLS maximum flexion angle has a weak linear relationship to knee extensor strength. SLS performance has high specificity but low sensitivity in identifying extensor mechanism strength deficits. The SLS maximum flexion angle is therefore a suboptimal surrogate test to identify extensor mechanism strength deficits as diagnosed by isokinetic dynamometric testing. However, unsatisfactory SLS performance indicates a very high chance of underlying extensor mechanism weakness.

Barfod, KW, Feller, JA, Clark, R, Hartwig, T, Devitt, BM, and Webster, KE. Strength testing after anterior cruciate ligament reconstruction: A prospective cohort study investigating overlap of tests. J Strength Cond Res 33(11): 3145-3150, 2019-The purpose of the present study was to determine whether overlap (redundancy) exists between individual tests in a comprehensive strength testing protocol used after anterior cruciate ligament reconstruction (ACLR). If overlap is present, one or more components of the protocol could potentially be omitted to make the testing protocol more efficient, but without compromising the usefulness of the testing. Sixty-nine patients (46 male and 23 female patients; mean age 28 years) were strength tested at 6 and 12 months after ACLR as part of a prospective cohort study. The following knee flexor and extensor strength tests were performed: isokinetic concentric strength at 60 and 180°·s, isokinetic eccentric strength at 60°·s, and isometric knee flexor strength at 60° flexion. Peak and average torque values were extracted, and the ratio between the operated and non-operated limb was calculated as a limb symmetry index. Overlap of strength tests was investigated by fitting a linear regression model to the data with an R threshold of 0.56 used as an indication of overlap. Overlap between peak and mean torque was present for extensor and flexor concentric and eccentric measurements at 12 months and for concentric measurements at 6 months. Peak torque measurements were therefore used for subsequent analysis. Concentric extensor peak torque at 60 and 180°·s showed overlap at 6 months (R = 0.73) but not at 12 months (R = 0.37). No other overlap was identified. In conclusion, there is little room for omission of individual strength testing protocol components because of the lack of overlap between tests. Isometric, eccentric, and concentric tests may all provide unique information and all, therefore, should be considered for inclusion.

Background: Many studies have investigated factors that predict a return to sport participation after anterior cruciate ligament (ACL) reconstruction, but it is unclear whether the same factors are associated with a return to preinjury level of sport performance., Purpose: To identify factors that contribute to an athlete's return to preinjury level of performance after ACL reconstruction., Study Design: Cohort study; Level of evidence, 2., Methods: A cohort of 222 patients (132 male, 90 female) who had ACL reconstruction surgery and completed a 12-month postoperative assessment were followed out to a mean 3 years (range, 2-4 years) to determine whether they had returned to their self-reported preinjury levels of sport performance. Rates of return to preinjury performance were calculated. Measures that had been recorded at the 12-month postoperative review-demographic (age, sex), sport activity level (Marx Activity Rating Scale, return to competition sport), knee laxity, limb symmetry (single and triple crossover hop), subjective function/symptoms (International Knee Documentation Committee subjective), and psychological readiness (Anterior Cruciate Ligament Return to Sport After Injury scale)-were compared between patients who returned to their preinjury levels of performance and those who did not. Univariate and multivariate logistic regression models were also used to prospectively determine the association between these measures and return to preinjury level of sport performance., Results: A total of 135 (61%) patients reported that they had returned to their preinjury levels of performance, with return rates similar between males (59%) and females (63%) and between those who had returned to competition at 12 months (62%) and those who had not (60%). There was no significant age difference between patients who returned to their preinjury levels of sport performance and those who did not; however, higher psychological readiness ( P < .0001), greater limb symmetry ( P < .05), higher subjective knee scores ( P = .01), and a higher activity level ( P < .04) were all associated with a return to performance. In the multivariate model, psychological readiness was the only variable that remained a significant predictor (odds ratio = 1.03; 95% CI, 1.01-1.04; P < .0001)., Conclusion: A majority of athletes who returned to sport after ACL reconstruction reported that their performance was comparable with preinjury. Having a greater psychological readiness to return during rehabilitation was the most significant predictor of a subsequent return to comparable performance.

Background: People who have had anterior cruciate ligament reconstruction (ACLR) are at a high risk of developing tibiofemoral joint (TFJ) osteoarthritis (OA), with concomitant meniscal injury elevating this risk. This study aimed to investigate OA-related morphological change over 2 years in the TFJ among individuals who have undergone ACLR with or without concomitant meniscal pathology and in healthy controls. A secondary aim was to examine associations of baseline TFJ cartilage defects and bone marrow lesions (BML) scores with tibial cartilage volume change in ACLR groups., Methods: Fifty seven ACLR participants aged 18-40 years (32 isolated ACLR, 25 combined meniscal pathology) underwent knee magnetic resonance imaging (MRI) 2.5 and 4.5 years post-surgery. Nine healthy controls underwent knee MRI at the ~ 2-year intervals. Tibial cartilage volume, TFJ cartilage defects and BMLs were assessed from MRI., Results: For both ACLR groups, medial and lateral tibial cartilage volume increased over 2 years (P <  0.05). Isolated ACLR group had greater annual percentage increase in lateral tibial cartilage volume compared with controls and with the combined group (P = 0.03). Cartilage defects remained unchanged across groups. Both ACLR groups showed more lateral tibia BML regression compared with controls (P = 0.04). Baseline cartilage defects score was positively associated with cartilage volume increase at lateral tibia (P = 0.002) while baseline BMLs score was inversely related to medial tibia cartilage volume increase (P = 0.001) in the pooled ACLR group., Conclusions: Tibial cartilage hypertrophy was apparent in ACLR knees from 2.5 to 4.5 years post-surgery and was partly dependent upon meniscal status together with the nature and location of the underlying pathology at baseline. Magnitude and direction of change in joint pathologies (i.e., cartilage defects, BMLs) were less predictable and either remained stable or improved over follow-up.

Background: Achieving preinjury levels of athletic performance has been challenging for elite athletes after anterior cruciate ligament (ACL) reconstruction. Although a recent study found that 77% of Australian Football League (AFL) players who underwent ACL reconstruction from 1999 to 2013 returned to play at the highest level, the study did not indicate how consistently or well they were able to play., Purpose: To identify the number of AFL players who returned to play consistently over 2 seasons after ACL reconstruction, compare their playing performance in these seasons with preinjury performance, and evaluate factors associated with returning to preinjury levels of performance., Study Design: Case series; Level of evidence, 4., Methods: Analysis included 104 AFL players who underwent ACL reconstruction between 1999 and 2013. All had played at least 10 AFL matches in 1 season before ACL injury. Ranking points, as devised by AFL statisticians, were used to measure individual playing performance., Results: Of the 104 players who played at least 10 matches in 1 season before ACL injury, 53 (51%) returned to play at least 10 matches in 2 seasons after surgery. Of these 53 players, 36 (68%) returned to their preinjury levels of performance. The 17 remaining players who did not return to their preinjury performance still performed comparably to the AFL average level after surgery. Players <25 years old (odds ratio = 2.9, P = .01) or <90 kg (odds ratio = 2.7, P = .03) had greater odds of returning to their preinjury levels of performance., Conclusion: Returning to play on a consistent basis was a substantial challenge for AFL players after ACL reconstruction. However, among players who did return to play consistently over 2 seasons, their postsurgery average performance was comparable with the AFL average level of performance, and two-thirds returned to their preinjury levels of performance. Younger and lighter players were more likely to return to their preinjury levels of performance, possibly given the nature of AFL club playing list management decisions.

Background: Lower psychological readiness to return to sport has been reported for younger patients (≤20 years) who go on to a second anterior cruciate ligament (ACL) injury. However, changes in psychological readiness and specific psychological responses associated with second injury have not been identified., Purpose/hypothesis: To identify changes in psychological readiness over time associated with a second ACL injury. It was hypothesized that younger patients who suffered a second injury would have smaller changes in psychological readiness to return to sport when compared with those who did not have a second injury., Study Design: Case-control study; Level of evidence, 2., Methods: Patients ≤20 years old at the time of surgery who had a primary ACL reconstruction procedure between June 2014 and June 2016 were recruited for this study. The short version of the Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI) scale was completed by patients before their ACL reconstruction and repeated at 12 months after surgery to assess psychological readiness to return to sport. The primary outcome of interest was the relationship between the change in psychological readiness and second ACL injuries., Results: Among 115 young patients who returned to sport after ACL reconstruction, 21 (18%) experienced a second ACL injury. Injured patients did not show improvement in their ACL-RSI score between the preoperative assessment and 12-month time point (58.5 vs 60.8 points, P = .60) and had a significantly smaller change when compared with noninjured patients (9.2 vs 24.9 points, P = .01). When compared with the noninjured group, the injured group reported they were more nervous about playing sport, less confident in playing sport without concern for the knee, more frustrated with having to consider the knee with respect to sport, and more fearful of reinjuring the knee by playing sport ( P≤ .05)., Conclusion: Injured patients exhibited less improvement in psychological readiness at a group level and reported different psychological characteristics with regard to return to sport at 12 months after ACL reconstruction as monitored by the ACL-RSI scale.

Purpose: External loading of osteoarthritic and healthy knees correlates with current and future osteochondral tissue state. These relationships have not been examined following anterior cruciate ligament reconstruction. We hypothesised greater magnitude tibiofemoral contact forces were related to increased prevalence of osteochondral pathologies, and these relationships were exacerbated by concomitant meniscal injury., Methods: This was a cross-sectional study of 100 individuals (29.7 ± 6.5 years, 78.1 ± 14.4 kg) examined 2-3 years following hamstring tendon anterior cruciate ligament reconstruction. Thirty-eight participants had concurrent meniscal pathology (30.6 ± 6.6 years, 83.3 ± 14.3 kg), which included treated and untreated meniscal injury, and 62 participants (29.8 ± 6.4 years, 74.9 ± 13.3 kg) were free of meniscal pathology. Magnetic resonance imaging of reconstructed knees was used to assess prevalence of tibiofemoral osteochondral pathologies (i.e., cartilage defects and bone marrow lesions). A calibrated electromyogram-driven neuromusculoskeletal model was used to predict medial and lateral tibiofemoral compartment contact forces from gait analysis data. Relationships between contact forces and osteochondral pathology prevalence were assessed using logistic regression models., Results: In patients with reconstructed knees free from meniscal pathology, greater medial contact forces were related to reduced prevalence of medial cartilage defects (odds ratio (OR) = 0.7, Wald χ 2 (2) = 7.9, 95% confidence interval (CI) = 0.50-95, p = 0.02) and medial bone marrow lesions (OR = 0.8, Wald χ 2 (2) = 4.2, 95% CI = 0.7-0.99, p = 0.04). No significant relationships were found in lateral compartments. In reconstructed knees with concurrent meniscal pathology, no relationships were found between contact forces and osteochondral pathologies., Conclusions: In patients with reconstructed knees free from meniscal pathology, increased contact forces were associated with fewer cartilage defects and bone marrow lesions in medial, but not, lateral tibiofemoral compartments. No significant relationships were found between contact forces and osteochondral pathologies in reconstructed knees with meniscal pathology for any tibiofemoral compartment. Future studies should focus on determining longitudinal effects of contact forces and changes in osteochondral pathologies., Level of Evidence: IV.

Background: Psychological responses after anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) have been identified as predictors of return to sport but have not been investigated in relation to further injury., Purpose/hypothesis: To determine whether psychological readiness to return to sport is associated with second ACL injury. It was hypothesized a priori that at both preoperative and 12-month postoperative time points, patients who sustained a second ACL injury would have lower psychological readiness than patients who did not have a second injury., Study Design: Cohort study; Level of evidence, 2., Methods: Patients who had a primary ACLR procedure between June 2014 and June 2016 completed the ACL-Return to Sport after Injury (ACL-RSI) (short version) scale before their ACLR and repeated the scale at 12 months after surgery to assess psychological readiness to return to sport. Patients were followed for a minimum of 2 years (range, 2-4 years) after surgery to determine further injury. The primary outcome was the relationship between ACL-RSI scores and the incidence of second ACL injury., Results: In 329 patients who returned to sport after ACLR, 52 (16%) sustained a second ACL injury. No difference in psychological readiness was observed at the preoperative time point, but patients who sustained a second injury trended toward lower psychological readiness at 12 months compared with noninjured patients (60.9 vs 67.2 points; P = .11). Younger (≤20 years) patients with injury had significantly lower psychological readiness to return to sport than young noninjured patients (60.8 vs 71.5 points; P = .02), but no difference was found in older patients (60.9 vs 64.6 points; P = .58). In younger patients, receiver operating characteristic curve analysis revealed a cutoff score of 76.7 points with 90% sensitivity to identify younger patients who sustained a second ACL injury., Conclusion: Younger patients with lower psychological readiness are at higher risk for a second ACL injury after return to sport.

Background: There is limited information about patient expectations regarding return to sport after anterior cruciate ligament reconstruction (ACLR). While it has generally been assumed that patients expect to return, it has also been acknowledged that expectations may change after surgery., Purpose: To investigate return-to-sport expectations before and after ACLR and determine factors associated with changed expectations., Study Design: Cohort study; Level of evidence, 2., Methods: The study sample consisted of 675 eligible patients (437 male, 238 female). Return-to-sport expectations were recorded preoperatively. Primary ACLR was performed in 595 patients (of whom 81 had a prior contralateral ACLR) and revision ACLR in 80 patients. At 12 months after surgery, the return to preinjury sport status was assessed along with patients' current sport expectations. The proportion of patients who expected to return to their preinjury level of sport was determined along with actual return rates. Logistic regression was performed to determine the factors associated with the decision to cease sport participation in patients who had expected to be able to return to their preinjury level of sport., Results: Overall, 84% of patients expected to be able to return to their preinjury level of sport. Expectations were higher for patients about to undergo their first ACLR, with 88% expecting to return, than for those about to undergo revision surgery or second primary ACLR (63% and 80% expected to return, respectively; P < .001 and P = .08, respectively). At 12 months after surgery, 24% of patients who expected to return to their preinjury level of sport had actually returned, and 15% of all patients had already decided to give up sport. In the regression models, being female ( P = .02) and having undergone previous ACLR ( P < .0001) were factors significantly associated with the decision to give up sport participation., Conclusion: Patients had high expectations for returning to their preinjury level of sport at the time of undergoing initial ACLR. Expectations were lower for those who had undergone previous ACLR. Female patients and patients who had undergone previous ACLR were more likely to change their expectations and cease sport participation. These data can be used to provide patients with realistic return-to-sport expectations in the first postoperative year and highlight the challenge for patients who aim to return from multiple ACL injuries.

Background: Patients with bilateral anterior cruciate ligament (ACL) injuries tend to report worse results in terms of knee function and quality of life as compared with those with unilateral injury. There are limited data regarding return to preinjury sport in this group., Purpose: To report return-to-sport rates for patients who had bilateral ACL reconstruction and to compare outcomes according to age and sex., Study Design: Case series; Level of evidence, 4., Methods: A total of 107 patients (62 male, 45 female) who underwent primary ACL reconstruction surgery to both knees completed a detailed sports activity survey at a mean 5-year follow-up (range, 2.5-10 years). Follow-up also included the International Knee Documentation Committee subjective form, Marx Activity Scale, and Knee injury and Osteoarthritis Outcome Score-Quality of Life subscale. Rates of return to preinjury levels of sport were calculated for the whole cohort, and for further analysis, the group was divided according to age (<25 vs ≥25 years), sex, and time between the reconstruction procedures (<3 vs ≥3 years)., Results: The rate of return to preinjury sport after bilateral ACL reconstruction was 40% (95% CI, 31%-50%), as compared with an 83% (95% CI, 74%-88%) return rate after the first reconstruction procedure. Although not statistically significant, return rates were higher for male versus female patients (47% vs 31%) and older versus younger patients (45% vs 31%). Of those who returned to their preinjury levels of sport after the second reconstruction, 72% thought that they could perform as well as before their ACL injuries. In contrast, only 20% thought that they could perform as well if they returned to a lower level. Fear of reinjury was the most common reason cited for failure to return to sport after the second reconstruction. Patient-reported outcome scores were higher for those who returned to their preinjury levels of sport but did not differ for sex and age., Conclusion: Return-to-sport rates drop markedly after a second (contralateral) ACL reconstruction, with less than half of the investigated cohort returning to its preinjury level of sport. Return-to-sport outcomes are less than ideal for patients who have ACL reconstruction surgery to both knees.

Most athletes who undergo anterior cruciate ligament (ACL) reconstruction surgery plan to return to some level of sporting activity. However, rates of return to pre-injury sport are often less than might be expected and many factors influence whether individuals return to sport after this surgery. They include surgical and rehabilitation factors as well as social, psychological and demographic characteristics. The fate of the younger athlete who sustains an ACL injury is a topic that has received recent attention due to accumulating evidence that younger athletes are at considerable risk for not only one, but multiple ACL injuries. Little is known about how to determine when it is safe to return to sport following ACL reconstruction or how to predict whether an athlete will be able to successfully return. The notion that a set of return to sport criteria can be applied to reduce the risk of further injury has become popular with many different criteria proposed. Another risk of returning to sport following ACL reconstruction is that of sustaining injury to the menisci or articular surfaces, which may in turn increase the risk of developing osteoarthritis. Although there is some evidence that ACL reconstruction reduces the risk of osteoarthritis there is stronger evidence that it does little to protect the knee from long term degeneration. Therefore, it should be recognized that return to sport following ACL reconstruction is associated with a risk of further injury and potential development of osteoarthritis.Level of evidence: V.

Background: Knee extensor strength and single limb hop for distance have been suggested as useful measures to evaluate readiness to return to sport after anterior cruciate ligament (ACL) reconstruction. The aim of the study was to examine the association between knee extensor strength and single leg hop for distance following ACL reconstruction and to determine the proportion of patients with knee extensor strength symmetry deficits at six and 12 months., Methods: From December 2013 to December 2015 69 patients aged 14 to 45 undergoing primary ACL reconstruction were recruited. Isokinetic concentric knee extensor strength testing and single limb hop for distance were performed six and 12 months postoperatively. Satisfactory knee extensor strength was defined as a leg symmetry index (LSI) ≥85%., Results: At six months 27.5% (19/69) of patients had recovered satisfactory knee extensor strength in the injured leg, improving to 46.4% (32/69) at 12 months. Recovery of satisfactory strength was associated with hopping distance. Hop symmetry was achieved considerably faster than knee extensor symmetry, with 66.7% (46/69) of patients demonstrating satisfactory hopping symmetry at six months, 89.9% (62/69) at 12 months. Recovery of hopping distance was not associated with knee extensor strength., Conclusions: Single leg hop test cannot be used as a surrogate measure for knee extensor strength as no association was found between hop tests and knee extensor strength. Less than one in three patients at six months and one in two at 12 months had recovered satisfactory knee extensor strength., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Anterior cruciate ligament (ACL) injury has been a major cause of missed game time among Australian Football League (AFL) players. Return to play after ACL reconstruction is not always achieved, even among elite athletes. The rate of subsequent ACL injury in the AFL from 1990 to 2000 was high as compared with that of other elite sports., Purpose: To determine the rates of return to play and subsequent ACL injury after ACL reconstruction among AFL players from 1999 to 2013 and to explore factors associated with differing rates of return to play and subsequent ACL injury., Study Design: Case series; Level of evidence, 4., Methods: A total of 158 AFL players who underwent ACL reconstruction were identified from a prospectively maintained registry of AFL player injuries. Further data were gathered from official playing statistics, surgical records, and structured phone interviews., Results: The rate of return to play after an initial ACL injury was 77% (121 of 158 players). Greater preinjury playing experience and earlier selection in the AFL draft were associated with higher rates of return to play. The rate of subsequent ACL injury to either knee was 30% (48 of 158 players) and was especially high among players aged <21 years (23 of 46 players, 50%). After subsequent ACL injury, 34 of 48 players (71%) returned to play. In primary ACL reconstruction, the use of Ligament Augmentation and Reconstruction System grafts resulted in a faster return to play ( P = .001) but had a higher risk of subsequent revision reconstruction (risk ratio = 2.8, P = .048). Family history of ACL injury was associated with an increased risk of subsequent contralateral ACL injury (risk ratio = 3.8, P = .002)., Conclusion: Most AFL players who underwent ACL reconstruction returned to play at least 1 AFL match. The high rate of subsequent ACL injury among AFL players demonstrates the highly demanding nature of Australian football, particularly at the elite level. The risk factors for subsequent ACL injury should be considered carefully when treatment and rehabilitation decisions are made for these high-demand athletes.

Background: Anterior cruciate ligament (ACL) injury has a significant psychological effect, and a negative psychological state is a commonly cited reason for a reduction or cessation of sports participation after ACL reconstruction (ACLR) surgery., Purpose: To identify factors that contribute to an athlete's psychological readiness to return to sport (RTS) after ACLR., Study Design: Cross-sectional study; Level of evidence, 3., Methods: A cohort of 635 athletes (389 male, 246 female) who underwent ACLR and had been cleared to RTS completed the Anterior Cruciate Ligament-Return to Sport After Injury (ACL-RSI) scale at an average 12 months (range, 11-24 months) after surgery. Demographics (age, sex), sporting outcomes (preinjury frequency), surgical timing (injury to surgery interval), clinical factors (laxity), functional measures (single-limb hop symmetry), and symptoms of pain and function (International Knee Documentation Committee subjective) were also taken, and univariate and multiple regression models were used to determine the association between these and the psychological readiness of the athlete to RTS (ACL-RSI scores). Data for the entire cohort were initially analyzed; then, patients were grouped according to whether they had returned to competitive sport, and the analysis repeated for each group (return/nonreturn)., Results: Univariate analysis for the entire group showed that all of the following had a positive effect on psychological readiness: male sex (β = 5.8; 95% CI, 2-10), younger age (β = -0.2; 95% CI, -0.4 to 0.01), a shorter interval between injury and surgery (β = -0.1; 95% CI, -0.1 to -0.02), a higher frequency of preinjury sport participation (β = 5.4; 95% CI, 2-9), greater limb symmetry (β = 0.5; 95% CI, 0.3-0.6), and higher subjective knee scores (β = 1.3; 95% CI, 1.1-1.4). In the multivariate model, subjective knee scores and age significantly accounted for 37% of the variance in psychological readiness ( r 2 = 0.37, P < .0001). The only difference between the groups who had and had not returned to sport was that female sex was a significant contributor for the nonreturn group., Conclusion: Self-reported symptoms and function were most associated with psychological readiness to RTS after ACLR surgery. Male patients who participated frequently in sport before ACL injury had higher psychological readiness. Conversely, female patients had a more negative outlook and may therefore benefit more from interventions designed to facilitate a smooth transition back to sport.

Background: There are limited data evaluating the outcomes of revision anterior cruciate ligament (ACL) reconstruction surgery in younger patients despite recent reports that the rates of graft rupture are higher in young cohorts., Purpose: To explore the outcomes of revision ACL reconstruction surgery in younger patients with the specific aims of determining the rates of third ACL injury and whether knee pathology at the time of revision surgery and return to sport were associated with further injury., Study Design: Case-control study; Level of evidence, 3., Methods: The study cohort consisted of 151 consecutive patients who were aged 25 years or younger at the time of their first revision ACL reconstruction. The number of subsequent ACL injuries (graft rerupture or contralateral injury to the native ACL) was determined at a mean follow-up time of 4.5 years (range, 2-9 years). Surgical details were recorded, along with a range of sport participation outcomes. Contingency tables were used to assess the associations between subsequent ACL injury and return to sport, knee pathology, and the drilling of new femoral or tibial tunnels at revision surgery., Results: The follow-up rate was 85% (128/151). Graft reruptures occurred in 20 patients (16%) at a mean time of 2 years after revision surgery. Contralateral ACL injuries occurred in 15 patients (12%) at a mean time of 3.9 years. The total number of patients who had a third ACL injury was 35 (27%). There was a significant association between having medial meniscal pathology and sustaining a graft rerupture ( P = .03), but there was no association between graft rerupture and using the same tunnels from the primary procedure at revision surgery. After revision reconstruction, 68% of patients (95% CI, 55%-71%) returned to their preinjury level of sport, compared with 83% (95% CI, 69%-84%) after primary reconstruction in the same patients. Those who had a third ACL injury had a significantly higher rate of return to preinjury sport (83%) after the revision procedure than did the group that did not have further ACL injuries (62%, P = .02)., Conclusion: Younger patients are at significant risk of having multiple ACL injuries. The high rate of third ACL injuries presents a significant issue for future knee health in these young athletes. Medial meniscal pathology and returning to high-risk sport are factors that are significantly associated with the high multiple ACL injury rate in the young.

Objectives: The primary objective was to calculate the rate of return to sport (RTS) following anterior cruciate ligament (ACL) reconstruction in elite athletes. Secondary objectives were to estimate the time taken to RTS, calculate rates of ACL graft rupture, evaluate postsurgical athletic performance and identify determinants of RTS., Design: Pooled RTS and graft rupture rates were calculated using random effects proportion meta-analysis. Time to RTS, performance data and determinants of RTS were synthesised descriptively., Data Sources: MEDLINE, EMBASE, AMED, CINAHL, AMI, PEDro, SPORTDiscus and The Cochrane Library were searched from inception to 19 January 2016. Hand searching of 10 sports medicine journals and reference checking were also performed., Eligibility Criteria for Selecting Studies: Studies were included if they reported the ratio of elite athletes who returned to their preinjury level of sport following ACL reconstruction. Twenty-four studies were included., Results: The pooled RTS rate was 83% (95% CI 77% to 88%). The mean time to RTS ranged from 6 to 13 months. The pooled graft rupture rate was 5.2% (95% CI 2.8% to 8.3%). Six out of nine studies that included a noninjured control group found no significant deterioration in athletic performance following ACL reconstruction. Indicators of greater athletic skill or value to the team were associated with RTS., Summary and Conclusions: Eighty-three per cent of elite athletes returned to sport following ACL reconstruction, while 5.2% sustained a graft rupture. Most athletes who returned to sport performed comparably with matched, uninjured controls. This information may assist in guiding expectations of athletes and clinicians following ACL reconstruction., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: There is some evidence that functional performance and validated outcome scores differ according to the gender, age, and sport participation status of a patient after anterior cruciate ligament (ACL) reconstruction. However, the impact of these three factors, and interaction among them, has not been studied across a large relatively homogeneous group of patients to better elucidate their impact., Questions/purposes: We reviewed a large cohort of patients who had undergone ACL reconstruction to determine if ROM, knee laxity, objective performance measures, and validated outcome scores differed according to (1) gender; (2) age; and (3) sport participation status., Methods: This was a retrospective analysis of prospectively collected data. Between 2007 and 2016, we performed 3452 single-bundle ACL reconstructions in patients who participated in sport before ACL injury. Of those, complete followup (including preoperative scores and scores at 1 year after surgery; mean, 14 months; range, 12-20 months) was available on 2672 (77%) of patients. Those lost to followup and those accounted for were not different in terms of age, gender, and sports participation at baseline. The study group consisted of 1726 (65%) men and 946 (35%) women with a mean ± SD age of 28 ± 10 years. For these patients, the following measures were obtained: knee ROM (flexion and extension deficit), instrumented knee laxity, single and triple hop for distance limb symmetry index (LSI), International Knee Documentation Committee (IKDC) subjective evaluation, and Single Assessment Numeric Evaluation score. Mean scores and measures of variability were calculated for each outcome measure. Comparisons were made among gender, age, and sport status., Results: Men had less knee laxity after reconstruction (men 1.1 ± 2.2 mm, women 1.3 ± 2.4 mm; mean difference 0.2 mm [0.1-0.4], p < 0.001), greater limb symmetry (single limb hop men: 94% ± 12%, women 91% ± 13%, mean difference 3% [2%-4%], p < 0.001), and higher IKDC scores than did women (men 84 ± 12, women 82 ± 12, mean difference 2 [1-3], p < 0.001). With the exception of instrumented laxity, all outcome measures showed reduced deficits and higher scores in younger patients. This was most marked for LSI scores between the youngest and oldest aged patient groups (crossover hop: < 16 years 99% ± 10%, > 45 years 90% ± 16%, mean difference: 9 [5-11], p < 0.001). Patients who had returned to their preinjury sport also scored higher and had smaller deficits for all outcomes except ROM compared with patients who had not returned to sport at the time of followup (IKDC subjective: returned 90 ± 9, no sport 79 ± 12, mean difference 11 points [9-12], p < 0.001; single limb hop: returned 97 ± 10, no sport 91 ± 14, mean difference 6% [5%-7%], p < 0.001)., Conclusions: This study showed that some of the most commonly used functional performance and validated clinical scores for ACL reconstruction are superior for patients who are younger, male, and have returned to preinjury sport. Reference to these data allows clinicians to more effectively evaluate a patient based on their age, gender, and sport status when making return to sport and rehabilitation decisions., Level of Evidence: Level III, therapeutic study.

Purpose: Rupture of the anterior cruciate ligament (ACL) is a common and debilitating injury that impacts significantly on knee function and risks the development of degenerative arthritis. The outcome of ACL surgery is not monitored in Australia. The optimal treatment is unknown. Consequently, the identification of best practice in treating ACL is crucial to the development of improved outcomes. The Australian Knee Society (AKS) asked the Australian Orthopaedic Association (AOA) to consider establishing a national ACL registry. As a first step, a pilot study was undertaken by the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) to test the hypothesis that collecting the required information in the Australian setting was possible., Methods: Surgeons completed an operative form which provided comprehensive information on the surgery undertaken. Patients provided pre- and post-operative questionnaires including the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Marx Activity Scale (MA Scale). The number of ACL procedures undertaken at each hospital during the recruitment period was compared against State Government Health Department separation data., Results: A total of 802 patients were recruited from October 2011 to January 2013. The overall capture rate for surgeon-derived data was 99%, and the capture rate for the pre-operative patient questionnaire was 97.9%. At 6 months, patient-reported outcomes were obtained from 55% of patients, and 58.5% of patients at 12 months. When checked against State Government Health Department separation data, 31.3% of procedures undertaken at each study hospital were captured in the study., Conclusion: It is possible to collect surgeon-derived and pre-operative patient-reported data, following ACL reconstruction in Australia. The need to gain patient consent was a limiting factor to participation. When patients did consent to participate in the study, we were able to capture nearly 100% of surgical procedures. Patient consent would not be an issue in for a national registry where inclusion is automatic unless the patient wishes to opt out. The collection of post-operative patient-reported outcome measures (PROMs) is more problematic, due to an insufficient proportion of individuals providing patient-reported outcomes. Alternative outcome measures are required for an ACL registry in Australia to be successfully implemented., Level of Evidence: Diagnostic, Level III.

Purpose: The role of lateral extra-articular tenodesis (LEAT) as an augment to primary anterior cruciate ligament reconstruction (ACLR) remains controversial. However, concerns exist regarding the risk of development of osteoarthritis due to over constraint of the knee. To systematically review the literature to analyse the long-term incidence of osteoarthritis in patients who had an LEAT performed in isolation or in combination with intra-articular ACLR for the treatment of ACL deficiency., Methods: Two reviewers independently searched five databases for randomized controlled trials (RCTs), non-randomized comparative, and retrospective cohort studies (CS) with long-term radiological follow-up of patients with ACL deficiency treated with ACLR combined with LEAT or LEAT in isolation. Risk of bias was performed using a modified Downs & Black's checklist. The primary outcome was the development of osteoarthritis. The studies were divided into those with moderate/severe osteoarthritis at between 5 to 10 years and >10-year follow-up. The rate of meniscal pathology at the time of the index surgery was recorded. A best evidence synthesis was performed., Results: Eight studies reported on 421 patients in which an LEAT procedure was carried out. There were two high-quality RCTs and six low-quality CS. The follow-up was between 5- and 10-years in 5 studies and >10-years in 3. The presence of moderate/severe osteoarthritis was not detected in three studies and was found in 4/44 (9%) and 13/70 (18.6%) patients in the other two. At 11 year follow-up, one study demonstrated no osteoarthritis, while the other two studies reported rates of 54/100 (54%) and 17/24 (71%) respectively at >24 years. In the latter two cases, the rate of meniscal pathology was >50%. A best evidence synthesis revealed that there was insufficient evidence that the addition of a LEAT to an ACLR resulted in an increased rate of osteoarthritis., Conclusion: The best available evidence would suggest that the addition of a LEAT to ACLR does not result in an increase rate of osteoarthritis of the knee. In knees that have undergone a combined ACLR and LEAT, the incidence of osteoarthritis was low up to 11 years but increased thereafter. The presence of meniscal injury at the index surgery was reported to be greater predictor of the development of osteoarthritis., Level of Evidence: IV.

Purpose: To examine differences in cartilage morphology between young adults 2-3 years post-anterior cruciate ligament reconstruction (ACLR), with or without meniscal pathology, and control participants., Methods: Knee MRI was performed on 130 participants aged 18-40 years (62 with isolated ACLR, 38 with combined ACLR and meniscal pathology, and 30 healthy controls). Cartilage defects, cartilage volume and bone marrow lesions (BMLs) were assessed from MRI using validated methods., Results: Cartilage defects were more prevalent in the isolated ACLR (69 %) and combined group (84 %) than in controls (10 %, P < 0.001). Furthermore, the combined group showed higher prevalence of cartilage defects on medial femoral condyle (OR 4.7, 95 % CI 1.3-16.6) and patella (OR 7.8, 95 % CI 1.5-40.7) than the isolated ACLR group. Cartilage volume was lower in both ACLR groups compared with controls (medial tibia, lateral tibia and patella, P < 0.05), whilst prevalence of BMLs was higher on lateral tibia (P < 0.001), with no significant differences between the two ACLR groups for either measure., Conclusions: Cartilage morphology was worse in ACLR patients compared with healthy controls. ACLR patients with associated meniscal pathology have a higher prevalence of cartilage defects than ACLR patients without meniscal pathology. The findings suggest that concomitant meniscal pathology may lead to a greater risk of future OA than isolated ACLR., Level of Evidence: III.

Background: Static standing balance can be safely assessed early following anterior cruciate ligament reconstruction (ACLR), and deficits may have important implications for long-term outcomes. This study includes a large cohort of people post-ACLR and has the primary aim of establishing whether inter-limb and sex differences exist, with a secondary aim of assessing the association between static balance variables and other outcome measures., Methods: A total of 414 patients with a primary ACLR performed a 30-s static single leg balance test. Centre of pressure (COP) path length, antero-posterior (AP) and medio-lateral (ML) sway range and slow and fast speed COP path-length were examined. Additional measures included single and triple hop distance and symmetry, knee flexion range of motion, ligament laxity and the International Knee Documentation Committee (IKDC) subjective knee evaluation form., Results: No significant inter-limb balance differences were present in females. Significant, yet small to negligible effect size (ES) differences were present in males for ML range (ES=0.19), and AP and ML axis slow speed path length (ES=0.11 and 0.23 respectively). Significant, negligible to moderate effect size (ES range=<0.01 to 0.60) sex differences were observed, with females showing reduced sway compared to males. No balance variables had associations with any other variable that were greater than weak., Discussion: Our findings provide evidence that primary ACLR does not appear to negatively impact single leg standing balance on the operated limb more than the non-operated side. The lack of association with other outcome measures warrants further longitudinal examination into the utility of static standing balance assessment., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Purpose: To investigate differences in anterior cruciate ligament-reconstructed (ACLR) and healthy individuals in terms of the magnitude of the tibiofemoral contact forces, as well as the relative muscle and external load contributions to those contact forces, during walking, running, and sidestepping gait tasks., Methods: A computational EMG-driven neuromusculoskeletal model was used to estimate the muscle and tibiofemoral contact forces in those with single-bundle combined semitendinosus and gracilis tendon autograft ACLR (n = 104, 29.7 ± 6.5 yr, 78.1 ± 14.4 kg) and healthy controls (n = 60, 27.5 ± 5.4 yr, 67.8 ± 14.0 kg) during walking (1.4 ± 0.2 m·s), running (4.5 ± 0.5 m·s) and sidestepping (3.7 ± 0.6 m·s). Within the computational model, the semitendinosus of ACLR participants was adjusted to account for literature reported strength deficits and morphological changes subsequent to autograft harvesting., Results: ACLR had smaller maximum total and medial tibiofemoral contact forces (~80% of control values, scaled to bodyweight) during the different gait tasks. Compared with controls, ACLR were found to have a smaller maximum knee flexion moment, which explained the smaller tibiofemoral contact forces. Similarly, compared with controls, ACLR had both a smaller maximum knee flexion angle and knee flexion excursion during running and sidestepping, which may have concentrated the articular contact forces to smaller areas within the tibiofemoral joint. Mean relative muscle and external load contributions to the tibiofemoral contact forces were not significantly different between ACLR and controls., Conclusions: ACLR had lower bodyweight-scaled tibiofemoral contact forces during walking, running, and sidestepping, likely due to lower knee flexion moments and straighter knee during the different gait tasks. The relative contributions of muscles and external loads to the contact forces were equivalent between groups.

Background: Younger age is being increasingly recognized as a risk factor for anterior cruciate ligament (ACL) graft rupture and contralateral ACL injury after ACL reconstruction. Recent reports estimate second ACL injury rates to be in the range of 20% to 40%, which is a significant concern and requires further exploration., Purpose: The primary purpose was to determine the rates of graft rupture and injury to the contralateral native ACL in younger athletes. We also sought to explore the influence of sex and age groupings (<18 years vs 18-19 years at the time of surgery) on the risk of subsequent ACL injury., Study Design: Cohort study; Level of evidence, 3., Methods: The study cohort consisted of 354 consecutive patients who were younger than 20 years when they underwent their first primary hamstring tendon autograft ACL reconstruction. The number of subsequent ACL injuries (graft rupture or a contralateral injury to the native ACL) was determined at a mean follow-up of 5 years (range, 3-10 years). Subgroup analysis included sex and age (<18 years vs 18-19 years at the time of surgery) comparisons. Descriptive statistics were calculated for the timing of ACL graft rupture and contralateral ACL injury., Results: The overall follow-up rate was 89% (316/354). Graft ruptures occurred in 57 patients (18%) at an average time of 1.8 years after surgery. Almost half (47%) occurred within the first postoperative year, and 74% occurred within the first 2 years. The highest graft rupture rate of 28.3% was in the youngest males (<18 years), and this was significantly higher than in females of the same age (12.9%), as well as in male patients older than 18 years (13.8%). Contralateral ACL injuries occurred in 56 patients (17.7%) at an average time of 3.7 years after surgery. There were no significant age- or sex-based differences for contralateral ACL injuries. The total number of patients who had at least 1 further ACL injury subsequent to the primary surgery was 110 (35%)., Conclusion: The high rate of subsequent ACL injury in younger patients was confirmed. Early graft ruptures were more prevalent in patients who underwent surgery when they were younger than 18 years versus those in the 18- to 19-year age group. Males had higher rates of graft rupture than did females, with the youngest males (<18 years) at the highest risk in the investigated cohort., (© 2016 The Author(s).)

Background: There are limited and inconsistent data regarding return-to-sport outcomes after revision anterior cruciate ligament reconstruction (ACLR)., Hypothesis: Return-to-sport rates will be lower after revision ACLR when compared with primary ACLR., Study Design: Case series; Level of evidence, 4., Methods: The study cohort consisted of 136 eligible patients who had undergone their first revision ACLR between March 2006 and March 2010. Of these, 109 patients (80%) completed a sports activity survey at a mean 5-year follow-up (range, 3-7 years). Follow-up also included the International Knee Documentation Committee (IKDC) subjective form, Marx Activity Scale, and Knee injury and Osteoarthritis Outcome Score-quality of life (KOOS-QOL) form. Operative details were obtained from the clinical record., Results: After revision ACLR, 46% (95% CI, 37%-55%) of patients returned to their preinjury level of sport, compared with 50% (95% CI, 41%-59%) after the primary reconstruction in the same patients. Of the patients who were not able to return to their preinjury level of sport after primary reconstruction, 33% improved to the point that they were able to do so after revision. Younger patients were more likely to have returned to their same level of sport (58% vs 38%, P < .05), while the rate of return was the same between male and female patients. Those who returned to their preinjury level of sport scored higher Marx (P < .01), KOOS-QOL (P < .001), and IKDC scores (P < .01) than those who did not. Patients with <50% thickness articular cartilage lesions at revision surgery were more likely to have returned to their preinjury level (52% vs 31%, P < .05) and had significantly better Marx (P < .01), KOOS-QOL (P < .01), and IKDC scores (P < .01) at follow-up. The status of the menisci at the time of revision surgery was not associated with rates of return to sport, but patients with an intact medial meniscus had significantly higher KOOS-QOL (P < .05) scores at follow-up., Conclusion: Return-to-sport rates of patients after revision ACLR were similar to those after their primary surgery but were still lower than the reported rates of ACLR patients who did not need revision surgery. Greater chondral pathologic abnormalities at revision surgery were associated with reduced function at follow-up., (© 2015 The Author(s).)

Background: Numerous studies have compared patellar tendon (PT) and hamstring tendon (HS) anterior cruciate ligament (ACL) reconstructions in the short to midterm, but fewer long-term results have been published., Hypothesis: There will be no difference in functional outcome between ACL reconstruction performed with PT and HS grafts, but PT grafts will have more donor site morbidity., Study Design: Randomized controlled trial; Level of evidence, 1., Methods: Sixty-five patients undergoing ACL reconstruction were randomized to receive either a PT graft or a 4-strand HS graft. Early results were reported at 4, 8, 12, 24, and 36 months. Forty-seven patients (22 of 31 PT and 25 of 34 HS) were reviewed at a mean of 15.3 years., Results: Four graft ruptures (1 PT, 3 HS) and 6 contralateral ACL injuries (4 PT, 2 HS) occurred in the group that was reviewed. There was no statistically significant difference between the groups for any of the variables measured. There was a similar incidence of anterior knee pain and kneeling pain in both groups. The previously observed increased extension deficit in the PT group at 3 years was not present at 15 years, and there was no significant between-group difference in knee laxity. A higher proportion of patients in the PT group were participating in sport on a weekly basis (73% PT, 48% HS; P = .05). There was no difference in the degree of osteoarthritis between the groups., Conclusion: This randomized controlled trial showed that HS and PT ACL reconstructions have comparable results at an average 15-year follow-up. Contrary to the study hypothesis, some of the graft differences seen at earlier review were not present at 15 years, and patients with PT grafts were more active in sport participation. Overall, both graft types provided good long-term subjective and objective outcomes., (© 2015 The Author(s).)

Purpose: To evaluate weight-bearing and joint symmetry during the double-leg squat exercise at baseline and after fatigue in patients who have undergone anterior cruciate ligament reconstruction (ACLR) compared to uninjured controls., Methods: Ten males who had returned to sport after primary ACLR participated along with ten uninjured male controls. Lower limb kinematic, kinetic and ground reaction force (GRF) data were collected during double-leg squats at baseline and after a generalised fatigue protocol. Symmetry indices were calculated for hip and knee external flexion moments and the vertical GRF (weight-bearing symmetry) at maximum squat depth. These were compared between ACLR and control groups before and after fatigue using ANOVA models., Results: The ACL group preferentially unloaded the reconstructed limb at baseline, but changed to a more symmetrical load distribution to perform the squat exercise in the fatigue condition. This same loading pattern was seen at both the knee and hip joints. The control group did not show any effect of fatigue. For both groups, symmetry indices were closer to zero (which indicated perfect symmetry) in the fatigue condition., Conclusions: When prescribing squat exercises, it should be recognised that initially, patients with ACLR tend to unload the affected knee. More symmetrical loading patterns may be achieved by inducing bilateral fatigue. When fatigued, loading symmetry was similar between this patient group and controls. This is relevant information for those who implement rehabilitation training programmes., Level of Evidence: III.

Background: A return to their preinjury level of sport is frequently expected within 1 year after anterior cruciate ligament (ACL) reconstruction, yet up to two-thirds of athletes may not have achieved this milestone. The subsequent sports participation outcomes of athletes who have not returned to their preinjury level sport by 1 year after surgery have not previously been investigated., Purpose: To investigate return-to-sport rates at 2 years after surgery in athletes who had not returned to their preinjury level sport at 1 year after ACL reconstruction., Study Design: Case series; Level of evidence, 4., Methods: A consecutive cohort of competitive- and recreational-level athletes was recruited prospectively before undergoing ACL reconstruction at a private orthopaedic clinic. Participants were followed up at 1 and 2 years after surgery with a sports activity questionnaire that collected information regarding returning to sport, sports participation, and psychological responses. An independent physical therapist evaluated physical function at 1 year using hop tests and the International Knee Documentation Committee knee examination form and subjective knee evaluation., Results: A group of 122 competitive- and recreational-level athletes who had not returned to their preinjury level sport at 1 year after ACL reconstruction participated. Ninety-one percent of the athletes returned to some form of sport after surgery. At 2 years after surgery, 66% were playing sport, with 41% playing their preinjury level of sport and 25% playing a lower level of sport. Having a previous ACL reconstruction to either knee, poorer hop-test symmetry and subjective knee function, and more negative psychological responses were associated with not playing the preinjury level sport at 2 years., Conclusion: Most athletes who were not playing sport at 1 year had returned to some form of sport within 2 years after ACL reconstruction, which may suggest that athletes can take longer than the clinically expected time of 1 year to return to sport. However, only 2 of every 5 athletes were playing their preinjury level of sport at 2 years after surgery. When the results of the current study were combined with the results of athletes who had returned to sport at 1 year, the overall rate of return to the preinjury level sport at 2 years was 60%. Demographics, physical function, and psychological factors were related to playing the preinjury level sport at 2 years after surgery, supporting the notion that returning to sport after surgery is multifactorial., (© 2015 The Author(s).)

Background: The aim of this study was to update our original systematic review of return to sport rates following anterior cruciate ligament (ACL) reconstruction surgery., Method: Electronic databases were searched from April 2010 to November 2013 for articles reporting the number of patients returning to sport following ACL reconstruction surgery. Return to sport rates, physical functioning and contextual data were extracted and combined using random-effects meta-analyses. Data from the original review (articles published up to April 2010) were combined with data from the updated search., Results: Sixty-nine articles, reporting on 7556 participants, were reviewed. On average, 81% of people returned to any sport, 65% returned to their preinjury level of sport and 55% returned to competitive level sport after surgery. Symmetrical hopping performance (d=0.3) and the contextual factors of younger age (d=-0.3), male gender (OR=1.4), playing elite sport (OR=2.5) and having a positive psychological response (d=0.3) favoured returning to the preinjury level sport. Receiving a hamstring tendon autograft favoured returning to competitive level sport (OR=2.4), whereas receiving a patellar tendon autograft favoured returning to the preinjury level sport (OR=1.2)., Conclusions: Returning to sport varied according to different physical functioning and contextual factors, which could warrant additional emphasis in postoperative rehabilitation programmes to maximise participation., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Purpose: The purpose of the study was to report SF-36 data from a large cohort with anterior cruciate ligament (ACL) reconstruction surgery and compare between the SF-36 and SF-12., Methods: 1,500 patients completed the SF-36 at a minimum 12 months following ACL reconstruction surgery. The items which make up the SF-12 were selected and subscale scores were calculated and compared with the SF-36. The physical and mental component summary scores were calculated for both versions and correlated with disease-specific outcomes and were compared between different patient groups. In addition, the percentage of patients with below average, average, or above average general health was tabulated., Results: Over 90% of the cohort scored in the average or above average range for both physical and mental health component summary scores. Correlations between SF-36 and SF-12 scores were above 0.8 for all subscales except general health. Mean differences between the two versions were small except for the bodily pain subscale for which the SF-12 was 8.17 points higher than the SF-36 (0-100 scoring). For both versions, disease-specific measures were more highly correlated with the physical component score than the mental component score. Both versions were able to similarly distinguish between primary and revision procedures and groups that were and were not participating in sports., Conclusions: Following ACL reconstruction, patients generally have excellent health. The SF-12 provides a simple health outcome assessment following ACL reconstruction surgery and is an adequate alternative for the SF-36 for measures made at a single time point. The bodily pain subscale for the SF-12 may lack sensitivity, and disease-specific measures of pain should therefore also be included., Level of Evidence: I.

Background: Graft rupture of the same knee or injury to the anterior cruciate ligament (ACL) in the contralateral knee is a devastating outcome after ACL reconstruction surgery. While a number of factors have been identified as potentially increasing the risk of subsequent ACL injury, the literature is far from definitive., Purpose: To determine the rates of graft rupture and contralateral ACL injury in a large cohort and to investigate patient characteristics that may be associated with these., Study Design: Case-control study; Level of evidence, 3., Methods: A consecutive cohort of 750 patients who had undergone primary ACL reconstruction surgery with a minimum 3-year follow-up were questioned about the incidence of ACL graft rupture, contralateral ACL injury, family history of ACL injury, and current activity level. Patient databases provided details for age, sex, original injury mechanism, meniscus or articular surface injury, and graft diameter., Results: Responses were received from 561 patients (75%) at a mean ± SD follow-up time of 4.8 ± 1.1 years. Anterior cruciate ligament graft ruptures occurred in 25 patients (4.5%), and contralateral ACL injuries occurred in 42 patients (7.5%). The highest incidence of further ACL injury occurred in patients younger than 20 years at the time of surgery. In this group, 29% sustained a subsequent ACL injury to either knee. The odds for sustaining an ACL graft rupture or contralateral injury increased 6- and 3-fold, respectively, for patients younger than 20 years. Returning to cutting/pivoting sports increased the odds of graft rupture by a factor of 3.9 and contralateral rupture by a factor of 5. A positive family history doubled the odds for both graft rupture and contralateral ACL injury., Conclusion: Patients younger than 20 years who undergo ACL reconstruction are at significantly increased risk for both graft rupture and contralateral ACL injury. Whether age per se is a risk factor or age represents a proxy for other factors remains to be determined.

Purpose: To determine whether coronal graft orientation and tunnel placement for single-bundle anterior cruciate ligament (ACL) reconstruction is associated with tibial rotation excursion during functional activities., Methods: Eighty-four patients who had undergone ACL reconstruction over a ten-year time span had tibial rotation measured during level walking, using a three-dimensional motion analysis system. Fifty-two patients also had measures taken during the more dynamic task of single-limb landing. During the 10-year period, the position of the graft was deliberately changed from a vertical to more horizontal orientation in the coronal plane. Post-operative radiographs were analysed for the coronal graft orientation and femoral and tibial tunnel positions. Radiographic measurements of graft orientation and tunnel position were then correlated with the amount of tibial rotational excursion recorded during the walking and landing tasks., Results: For the single-limb landing task, a significant positive correlation was observed between the coronal graft angle and rotational excursion (R = 0.35, R (2)  = 0.12, p = 0.01). This indicated greater rotational excursion was associated with vertical graft orientation, but only explained 12 % of the variance. No correlations were found between coronal graft angle and tibial rotation during level walking., Conclusions: These findings support the notion that ACL graft orientation may play a role in rotational kinematics of the ACL-reconstructed knee, particularly during higher impact activities., Level of Evidence: IV.

Background: Up to two-thirds of athletes may not return to their preinjury level of sport by 12 months after anterior cruciate ligament (ACL) reconstruction surgery, despite being physically recovered. This has led to questions about what other factors may influence return to sport., Purpose: To determine whether psychological factors predicted return to preinjury level of sport by 12 months after ACL reconstruction surgery., Study Design: Case control study; Level of evidence, 3., Methods: Recreational and competitive-level athletes seen at a private orthopaedic clinic with an ACL injury were consecutively recruited. The primary outcome was return to the preinjury level of sports participation. The psychological factors evaluated were psychological readiness to return to sport, fear of reinjury, mood, emotions, sport locus of control, and recovery expectations. Participants were followed up preoperatively and at 4 and 12 months postoperatively., Results: In total, 187 athletes participated. At 12 months, 56 athletes (31%) had returned to their preinjury level of sports participation. Significant independent contributions to returning to the preinjury level by 12 months after surgery were made by psychological readiness to return to sport, fear of reinjury, sport locus of control, and the athlete's estimate of the number of months it would take to return to sport, as measured preoperatively (χ(2) 2 = 18.3, P < .001, classification accuracy = 70%) and at 4 months postoperatively (χ(2) 4 = 38.7, P < .001, classification accuracy = 86%)., Conclusion: Psychological responses before surgery and in early recovery were associated with returning to preinjury level of sport at 12 months, suggesting that attention to psychological recovery in addition to physical recovery after ACL injury and reconstruction surgery may be warranted. Clinical screening for maladaptive psychological responses in athletes before and soon after surgery may help clinicians identify athletes at risk of not returning to their preinjury level of sport by 12 months.

Objectives: To examine fear of re-injury in athletes who had returned to regular sports participation following anterior cruciate ligament reconstruction surgery., Design: Cross-sectional case series., Methods: A self-report questionnaire was used to collect data 2-7 years following surgery. Key inclusion criteria were regular participation in sport prior to injury and participation in sport at the time of the study., Results: A sample of 209 (88 females, 121 males) at a mean of 39.6 ± 13.8 months post surgery participated. Overall, participants did not express fear of re-injury, scoring >6/10 (where 10 was the most positive response) on all questions. In terms of the total score and for six out of eight questions, participants who returned to their pre-injury sports level had significantly less fear of re-injury than those who had not returned to their pre-injury level. Females had significantly more concern than males about the environmental conditions experienced while playing (mean 6.1 compared to 7.5). On three out of eight questions, individuals who had surgery more than 3 months after injury had a greater fear of re-injury than those who had their surgery closer to the time of injury., Conclusions: Athletes participating in sport 2-7 years following their anterior cruciate ligament reconstruction generally appear to do so without fear of re-injury. However, gender, the timing of surgery following injury and the level of sport the athletes returned to may be associated with fear of re-injury following surgery., (Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

Purpose: The external knee adduction moment during gait has previously been associated with knee osteoarthritis, and although it has been shown to be greater following anterior cruciate ligament (ACL) reconstruction surgery compared to a control group, it has not been compared between different graft types. Given that the incidence of radiographic knee osteoarthritis appears to be greater following patellar tendon compared to hamstring tendon ACL reconstruction, this study tested the hypothesis that the knee adduction moment would also be increased following patellar tendon ACL reconstruction., Methods: In 48 male participants (16 patellar tendon graft, 16 hamstring graft and 16 controls), the external knee adduction moment was measured during level walking in a gait laboratory at mean of 10 months after surgery., Results: There was no difference in the knee adduction moment between the hamstring and patellar tendon groups, and both patient groups had a significantly reduced knee adduction moment compared to the control group. In the hamstring group, the smaller adduction moment was associated with the patients walking with less knee varus whereas in the patellar tendon group, the smaller moment was associated with the patients walking with a decreased vertical ground reaction force., Conclusions: These results indicate that in male patients during the early stages of recovery from ACL reconstruction, the knee adduction moment is not greater than controls for either hamstring or patellar tendon graft types. Although the knee adduction moment was similar between the two graft types, the overall magnitude of the moment was influenced by different biomechanical factors., Level of Evidence: III.

Following anterior cruciate ligament reconstruction (ACL) patients have altered movement patterns in the reconstructed knee during walking. There is limited information about these alterations over an extended period of time. This study was designed to present a longitudinal analysis of gait patterns following ACL reconstruction surgery. Assessments of level walking were undertaken in 16 participants at a mean 10 months (initial assessment) and again at 3 years (follow-up assessment) after ACL reconstruction surgery. Kinematic and kinetic variables were analysed using a two factor (time, limb) repeated measures ANOVA. Kinematic data showed that patients were able to achieve greater extension about the reconstructed knee at follow-up than at initial assessment. The reconstructed knee was significantly less internally rotated than the contralateral knee at the initial assessment but not at follow-up. Kinetic data showed a significant increase in the external knee extension moment for the reconstructed limb over time. There were also significant increases in the external knee adduction moment for both limbs at the follow-up assessment. The external knee adduction moment was however smaller in the reconstructed knee than the contralateral knee at both assessments. The results indicate that gait variables do change over time and that measurement at a single time point may not reflect the long term outcome of ACL reconstruction surgery. The changes were however small and may not be clinically relevant. However, the consistently reduced external knee adduction moment seen about the reconstructed knee in this study may suggest that factors other than joint moments influence degenerative change over time., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Purpose: The purpose of this study was to determine the effects of fatigue on lower limb biomechanics during landing in patients who had undergone anterior cruciate ligament (ACL) reconstruction surgery., Methods: Fifteen male participants who had undergone primary ACL reconstruction 15-19 months previously and 11 uninjured male control subjects had three-dimensional lower limb kinematics and kinetics quantified during single-limb landings, both before and during progression to fatigue. The single-limb landings were a vertical drop from a 30-cm platform, and subjects performed repetitive bilateral squats to induce fatigue., Results: Fatigue led to reduced flexion in the lower limb, increased hip and knee abduction, increased knee rotation, and reduced knee joint moments. The response to fatigue was similar between the ACL-reconstructed limb and the control group as well as the reconstructed limb and the contralateral limb. The only kinematic variable to show a between-group or between-limb difference was hip flexion at initial contact, whereby flexion was greater for the reconstructed side. Although knee flexion and adduction moments were smaller for the reconstructed knee compared with the contralateral knee, they were not different from the control group., Conclusions: The results show that having an ACL reconstruction does not necessarily mean greater vulnerability to the effect of fatigue during single-limb landing. Nonetheless, some of the landing positions that were observed with fatigue potentially compromise the knee and integrity of the ACL graft.