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The anticipated timeline for muscle strength as well as return to running and sports are some of the most common inquiries by patients undergoing anterior cruciate ligament reconstruction. Despite the popularity of this procedure, the answers to these inquiries are not well described in the literature. The purpose of this study was to evaluate the range of quadriceps strength percentage and function benchmarks at various points after anterior cruciate ligament reconstruction surgery based on sex, age, and graft. Design Observational Cohort Study Methods Patients who underwent anterior cruciate ligament reconstruction (ACLR) were evaluated at various points after their surgery with handheld dynamometer assessments. Additional hop and balance testing was performed and patients were evaluated for clearance for running and sport via a physical therapist directed functional movement assessment (FMA). The progression of quadriceps symmetry throughout the postoperative period was examined with multi-level models, estimates of time to reach 70%, 80%, and 90% quadriceps symmetry were obtained from the fitted model. Results A total of 164 patients were evaluated. Patients either received bone-tendon-bone (BTB) autograft (n=118) or BTB allograft (n=46) for their ACL graft. Average age was 31.1 years-of-age (SD: 13.6). Males undergoing ACLR using BTB autograft (n=53) were able to achieve 80% quadriceps symmetry earlier than females (n=65) (5.7 months vs 7.1 months), were cleared to return to run sooner (5.6 months vs 6.8 months) and passed an FMA exam earlier (8.5 months vs 10 months). Males undergoing ACLR with allograft (n=13) were able to achieve 80% quadriceps symmetry earlier than females (n=33) (3.9 months vs 5.4 months) and were cleared to run sooner (4.5 months vs 5.8 months). Conclusion Patients undergoing BTB autograft obtain 80% quadriceps symmetry at an average of 5.7 months for males and 7.1 months for females. Individuals under the age of 25 obtain their quadriceps symmetry faster and are cleared to return to running faster than individuals over 25. Male sex is associated with decreased amount of time to obtain clearance for running and for full activity. Male sex is associated with decreased amount of time to regain quadriceps symmetry however this was not significant. [ABSTRACT FROM AUTHOR]

Objectives: Anterior cruciate ligament (ACL) reconstruction is a commonly performed orthopaedic procedure, with mixed long-term outcomes in terms of reinjury and return to sports. The aim of this study was to investigate factors associated with clinically meaningful long term outcomes after ACL reconstruction, as measured by the Patient Acceptable Symptom State (PASS). Additionally, the study aimed to evaluate for differences in factors between male and female patients undergoing ACL reconstruction. Methods: Patients above the age of 14 years who underwent ACL reconstruction at a single institution were identified retrospectively. Data on demographics, operative notes, and medical history were recorded from the electronic medical records. These patients were contacted to obtain information about subsequent diagnoses and surgeries since their surgery, as well as the current state of their knee via the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation form. PASS was defined an IKDC score of 75.9 or higher based on the threshold identified by Muller et al. Univariate logistic regression was performed to identify predictors of achieving PASS, and variables were selected for inclusion in a multivariable logistic regression model based on univariate analysis, prior literature, and clinical relevance. Multivariate regression was stratified by sex. Results: A total of 479 patients (age 38 ± 13, 57% female) were included in the study with a mean follow up of 10 ± 5 years. Mean IKDC was 80.50 (16.3) (80.54 in males vs 80.45 in females, p > 0.9). PASS was achieved by 68% of patients (69% in males vs 67% in females, p = 0.6). Nine patients (1.9%) reported undergoing subsequent revision surgery (4 (2.0%) in males vs 5 (1.8%) in females, p > 0.9). Upon univariate analysis, age, body mass index (BMI), meniscectomy, revisions and skiing were identified as potential predictors for the multivariable model. Multivariable analysis found that higher BMI (odds ratio 0.95[0.91, 0.99], p = 0.019) and revisions (odds ratio 0.2 [0.04, 0.78], p = 0.025) had independent, negative associations with achievement of PASS. Participation in skiing (odds ratio 1.81 [1.12,2.99], p = 0.018) was found to be positively and independently associated with achieving PASS. Among males, higher BMI (0.9 [0.83, 0.99], p = 0.023) was negatively associated with PASS and participation in skiing (3.52 [1.63, 8.38], p =.002) was positively associated with PASS. Among females, revisions (OR 0.09 [0.00,0.63], p = 0.034) were negatively associated with achievement of PASS. Conclusions: At 10 years after ACL reconstruction, most patients reported an acceptable symptom state. Sex differences were observed in factors associated with achieving PASS after ACL reconstruction. Among males, BMI and skiing were found to be associated with PASS, while among females, revision surgery was a significant predictor. These results highlight the need for further investigation of sex-specific factors in ACL reconstruction outcomes. [ABSTRACT FROM AUTHOR]

Background: Coronal and sagittal malalignment of the knee are well-recognized risk factors for failure after anterior cruciate ligament (ACL) reconstruction (ACLR). However, the effect of axial malalignment on graft survival after ACLR is yet to be determined. Purpose: To evaluate whether increased tibiofemoral rotational malalignment, namely, tibiofemoral rotation angle (TFA) and tibial tubercle–trochlear groove (TT-TG) distance, is associated with graft failure after ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: In this retrospective matched control study of a single center's database, 151 patients who underwent revision ACLR because of graft failure (ACLR failure group, defined as symptomatic patients with anterior knee instability and an ACL graft tear appreciated on magnetic resonance imaging [MRI] and confirmed during arthroscopic surgery) were compared with a matched control group of 151 patients who underwent primary ACLR with no evidence of failure after ≥2-year follow-up (intact ACLR group). Patients were matched by sex, age, and meniscal injury during primary ACLR. Axial malalignment was assessed on preoperative MRI through the TFA and the TT-TG distance. Sagittal alignment was measured through the posterior tibial slope on MRI. The optimal TFA cutoff associated with graft failure was identified by a receiver operating characteristic curve. The Kaplan-Meier curve with log-rank analysis was performed to evaluate the influence of the TFA on ACLR longevity. Results: The mean age was 25.7 ± 10.4 years for the ACLR failure group and 25.9 ± 10.0 years for the intact ACLR group. Among all the included patients, 174 (57.6%) were male. In the ACLR failure group, the mean TFA was 5.8°± 4.5° (range, −5° to 16°), while it was 3.0°± 3.3° (range, −3° to 15°) in the intact ACLR group (P <.001). Neither the TT-TG distance nor the posterior tibial slope presented statistical differences between the groups. The receiver operating characteristic curve suggested an optimal TFA cutoff of 4.5° for graft failure (area under the curve = 0.71; P <.001; sensitivity, 68.2%; specificity, 75.5%). Considering this a threshold, patients who had a TFA ≥4.5° had 6.6 times higher odds of graft failure compared with patients with a TFA <4.5° (P <.001). Survival analysis demonstrated a 5-year survival rate of 81% in patients with a TFA <4.5°, while it was 44% in those with a TFA ≥4.5° (P <.001). Conclusion: An increased TFA was associated with increased odds of ACLR failure when the TFA was ≥4.5°. Measuring the TFA in patients with ACL tears undergoing reconstruction may inform the surgeon about additional factors that may require consideration before ACLR for a successful outcome. [ABSTRACT FROM AUTHOR]

Objectives: Coronal and sagittal malalignment of the knee are well-recognized risk factors for failure after anterior cruciate ligament reconstruction (ACLR). However, the effect of axial malalignment on ACLR graft survival is yet to be determined. This study aimed to evaluate whether increased tibiofemoral rotational malalignment, namely tibiofemoral rotation angle (TFA) and tibial tubercle-trochlear groove (TT-TG) distance, is associated with ACLR graft failure. Methods: In this matched-control study, 151 patients who underwent revision ACLR due to graft failure (failure ACLR group) were compared to a matched-control group of 151 patients who underwent primary ACLR with no evidence of failure after at least 2-years follow-up (intact ACLR group). Patients were matched by sex, age, and meniscal injury during primary ACLR. Axial malalignment was assessed on preoperative magnetic resonance imaging (MRI) through the TFA and the TT-TG distance. Sagittal alignment was measured through posterior tibial slope (PTS) on MRI. Optimal TFA cutoff associated with graft failure was identified by a receiver operating characteristic (ROC) curve. Kaplan-Meier curve with log-rank analysis was performed to evaluate the influence of TFA on ACLR longevity. Results: In the failure ACLR group, mean TFA was 5.8 ± 4.5 (range, -5 to 16) degrees while this mean was 3.0 ± 3.3 (range, -3 to 15) degrees in the intact ACLR group (p<0.001). Neither TT-TG distance nor PTS presented statistical differences between the groups. ROC curve suggested an optimal TFA cutoff of 4.5 degrees for ACLR graft failure. Considering this as a threshold, patients who presented TFA ≥ 4.5 degrees had 6.6-times higher likelihood of graft failure compared to patients with TFA < 4.5 degrees (p<0.001). Survival analysis demonstrated a 5-years survival of 81% in patients with TFA < 4.5 degrees, while it was 44% when TFA ≥ 4.5 degrees (p<0.001). Conclusions: Increased TFA was associated with increased odds of ACLR failure when the TFA was > 4.5 degrees. Measuring the TFA in patients with ACL tears undergoing reconstruction may inform the surgeon about additional factors that may require consideration prior to ACL reconstruction for a successful outcome. [ABSTRACT FROM AUTHOR]

Several anatomical anterior cruciate ligament (ACL) reconstruction techniques have been proposed to restore normal joint kinematics. However, the relative superiorities of these techniques with one another and traditional single-bundle reconstructions are unclear. Kinematic responses of five previously reported reconstruction techniques (single-bundle reconstruction using a bone-patellar tendon-bone graft [SBR-BPTB], single-bundle reconstruction using a hamstring tendon graft [SBR-HST], single-tunnel double-bundle reconstruction using a hamstring tendon graft [STDBR-HST], anatomical single-tunnel reconstruction using a hamstring tendon graft [ASTR-HST], and a double-tunnel double-bundle reconstruction using a hamstring tendon graft [DBR-HST]) were systematically analyzed. The knee kinematics were determined under anterior tibial load (134 N) and simulated quadriceps load (400 N) at 0°, 15°, 30°, 60°, and 90° of flexion using a robotic testing system. Anterior joint stability under anterior tibial load was qualified as normal for ASTR-HST and DBR-HST and nearly normal for SBR-BPTB, SBR-HST, and STDBR-HST as per the International Knee Documentation Committee knee examination form categorization. The analysis of this study also demonstrated that SBR-BPTB, STDBR-HST, ASTR-HST, and DBR-HST restored the anterior joint stability to normal condition while the SBR-HST resulted in a nearly normal anterior joint stability under the action of simulated quadriceps load. The medial-lateral translations were restored to normal level by all the reconstructions. The internal tibial rotations under the simulated muscle load were over-constrained by all the reconstruction techniques, and more so by the DBRHST. All five ACL reconstruction techniques could provide either normal or nearly normal anterior joint stability; however, the techniques over-constrained internal tibial rotation under the simulated quadriceps load. [ABSTRACT FROM AUTHOR]

This study was to investigate the in vivo tibiofemoral cartilage contact locations before and after anterior cruciate ligament (ACL) reconstruction at 6 and 36 months. Ten patients with unilateral ACL injury were included. A step-up motion was analyzed using a combined magnetic resonance modeling and dual fluoroscopic imaging techniques. The preoperative (i.e. ACL deficient and healthy contralateral) and postoperative cartilage contact locations at 6 and 36 months were analyzed. Similar patterns of the cartilage contact locations during the step-up motion were found for the preoperative and postoperative knee states as compared to the preoperative healthy contralateral side. At the end of step-up motion, the medial contact locations at postoperative 36 months were more anterior when compared to the preoperative healthy contralateral ( p =0.02) and 6 months postoperative knee states ( p =0.01). The changes of the cartilage contact locations at 36 months after ACL reconstruction compared to the healthy contralateral side were strongly correlated with the changes at 6 months postoperatively. This study showed that the tibiofemoral cartilage contact locations of the knee changes with time after ACL reconstruction, implying an ongoing recovery process within the 36 months after the surgery. There could be an association between the short-term (6 months) and longer-term (36 months) contact kinematics after ACL reconstruction. Future studies need to investigate the intrinsic relationship between knee kinematics at different times after ACL reconstruction. [ABSTRACT FROM AUTHOR]

Background Clinical outcome studies showed a high incidence of knee osteoarthritis after anterior cruciate ligament reconstruction. Abnormal joint kinematics and loading conditions were assumed as risking factors. However, little is known on cartilage contact forces after the surgery. Methods A validated computational model was used to simulate anatomic and transtibial single-bundle anterior cruciate ligament reconstructions. Two graft fixation angles (0° and 30°) were simulated for each reconstruction. Biomechanics of the knee was investigated in intact, anterior cruciate ligament deficient and reconstructed conditions when the knee was subjected to 134 N anterior load and 400 N quadriceps load at 0°, 30°, 60° and 90° of flexion. The tibial translation and rotation, graft forces, medial and lateral contact forces were calculated. Findings When the graft was fixed at 0°, the anatomic reconstruction resulted in slightly larger lateral contact force at 0° compared to the intact knee while the transtibial technique led to higher contact force at both 0° and 30° under the muscle load. When graft was fixed at 30°, the anatomic reconstruction overstrained the knee at 0° with larger contact forces, while the transtibial technique resulted in slightly larger contact forces at 30°. Interpretation This study suggests that neither the anatomic nor the transtibial reconstruction can consistently restore normal knee biomechanics at different flexion angles. The anatomic reconstruction may better restore anteroposterior stability and contact force with the graft fixed at 0°. The transtibial technique may better restore knee anteroposterior stability and articular contact force with the graft fixed at 30° of flexion. [ABSTRACT FROM AUTHOR]