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Background: Anterolateral knee laxity (ALLx) has been linked to tears of the lateral meniscus (LM) and anterior cruciate ligament (ACL) injury. Purpose: To investigate the longitudinal relationship between the signal intensity (SI) of the repaired LM on magnetic resonance imaging (MRI) and residual ALLx after ACL reconstruction (ACLR). Study Design: Cohort study; Level of evidence, 3. Methods: Included were 87 patients who underwent double-bundle ACLR and lateral meniscal repair (mean age, 23.5 years; body mass index, 23.7 kg/m2; 56 women) at a single institution between 2010 and 2019. Proton density-weighted (PDW) and T2-weighted (T2W) MRI was performed at 3, 6, and 12 months postoperatively, and the SI ratio (SIR) was calculated as (SI of the repaired LM)/(SI of the posterior cruciate ligament). At the 12-month follow-up, ALLx was evaluated using the pivot-shift test; an International Knee Documentation Committee grade ≥1 indicated residual ALLx. Results: Overall, 12 patients (13.8%) exhibited ALLx at 12 months postoperatively. At 3 months postoperatively, the SIR on PDW images (SIR-PDW) was significantly higher in patients with ALLx versus those without ALLx (1.98 ± 0.77 vs 1.49 ± 0.52, respectively; P = .007); there was no difference in the SIR on T2W images between the groups. SIR-PDW at 3 months postoperatively was correlated negatively with patient age (r = -0.308, P = .004). When patients were stratified into a younger (≤22 years; n = 53; ALLx = 7 [13.2%]) and an older (>22 years; n = 34; ALLx = 5 [14.7%]) group, the area under the receiver operating characteristic curves (AUCs) for SIR-PDW in the younger group were statistically significant for predicting the prevalence of ALLx at all follow-up times (AUCs, 0.733-0.788) with optimal cutoff values of 2.00 at 3 months, 1.50 at 6 months, and 1.50 at 12 months. Logistic regression analysis revealed that if younger patients consistently had higher SIR-PDW values than the cutoff values, they were more likely to have residual ALLx (odds ratios, 10.24-23.57). Conclusion: For younger patients who underwent both ACLR and lateral meniscal repair, higher MRI SI of the repaired LM was associated with a higher prevalence of residual ALLx. [ABSTRACT FROM AUTHOR]

Background: The bone–patellar tendon–bone (BTB) autograft is associated with difficulty with kneeling after anterior cruciate ligament (ACL) reconstruction; however, it is unclear whether it results in a more painful or symptomatic knee compared with the hamstring tendon autograft. Purpose: To identify the rate and risk factors for knee pain and difficulty with kneeling after ACL reconstruction. Study Design: Cohort study; Level of evidence, 3. Methods: Primary ACL reconstruction procedures prospectively recorded in the New Zealand ACL Registry from April 2014 to May 2021 were analyzed. The Knee injury and Osteoarthritis Outcome Score (KOOS) was used to identify patients reporting consequential knee pain (CKP), defined as a KOOS Pain subscore of ≤72 points, and severe kneeling difficulty (SKD), defined as a self-report of "severe" or "extreme" difficulty with kneeling. Absolute values of the KOOS Pain and Symptoms subscales were also compared. Results: A total of 10,999 patients were analyzed. At 2-year follow-up, 9.3% (420/4492) reported CKP, and 12.0% (537/4471) reported SKD. The most important predictor of CKP at 2-year follow-up was having significant pain before surgery (adjusted odds ratio, 4.10; P <.001). The most important predictor of SKD at 2-year follow-up was the use of a BTB autograft rather than a hamstring tendon autograft (21.3% vs 9.4%, respectively; adjusted odds ratio, 3.12; P <.001). There was no difference between the BTB and hamstring tendon grafts in terms of CKP (9.9% vs 9.2%, respectively; P =.494) or in absolute values of the KOOS Pain (mean, 88.7 vs 89.0, respectively; P =.37) and KOOS Symptoms (mean, 82.5 vs 82.1, respectively; P =.49) subscales. Conclusion: At 2-year follow-up after primary ACL reconstruction, 9.3% of patients reported CKP, and 12.0% reported SKD. The BTB autograft was associated with difficulty with kneeling, but it did not result in a more painful or symptomatic knee compared with the hamstring tendon autograft. [ABSTRACT FROM AUTHOR]

Background: Delayed anterior cruciate ligament (ACL) reconstruction has been associated with an increased risk of meniscal tears. However, studies comparing early versus delayed ACL reconstruction have not clearly demonstrated that meniscal tears diagnosed arthroscopically are new injuries as opposed to concomitant injuries sustained during ACL rupture. Purpose: To determine whether and how delay of ACL reconstruction is associated with risk of "new" meniscal tears (defined as those visualized arthroscopically that had not been detected on magnetic resonance imaging [MRI]) in adult and pediatric patients. Study Design: Cohort study; Level of evidence, 3. Methods: We retrospectively identified patients who underwent primary ACL reconstruction between 2013 and 2022 at our institution. To ensure that MRI reflected initial intra-articular pathology, we included only patients who had an MRI scan within 3 weeks after injury (173 pediatric and 369 adult patients). Multivariate Poisson regression was performed to calculate the adjusted relative risk (ARR) of new meniscal tears after delayed (≥8 weeks from injury) operative treatment. Results: The mean (± SD) time from injury to MRI was 1.0 ± 0.8 weeks for pediatric patients and 1.1 ± 0.7 weeks for adults. Less than half of the meniscal tears observed arthroscopically had been absent on initial MRI. New medial meniscal tears occurred in 15% of pediatric patients and 16% of adults. New lateral meniscal tears occurred in 48% of pediatric patients and 34% of adults. Among pediatric patients, delayed ACL reconstruction was associated with higher risk of new medial tears (ARR, 3.9; 95% CI, 1.5-10) but not lateral tears (ARR, 0.8; 95% CI, 0.4-1.5). In contrast, adults had no significant increase in risk of meniscal tears associated with operative delay. Conclusion: Delayed ACL reconstruction may be acceptable in adults, who may be less active and less injury-prone than children and adolescents. [ABSTRACT FROM AUTHOR]

Background: Peripheral tears of the posterior horn of the medial meniscus, known as "ramp lesions," are commonly found in anterior cruciate ligament (ACL)–deficient knees but are frequently missed on routine evaluation. Purpose: To predict the presence of ramp lesions in ACL-deficient knees using machine learning methods with associated risk factors. Study Design: Cohort study (Diagnosis); Level of evidence, 2. Methods: This study included 362 patients who underwent ACL reconstruction between June 2010 and March 2019. The exclusion criteria were combined fractures and multiple ligament injuries, except for medial collateral ligament injuries. Patients were grouped according to the presence of ramp lesions on arthroscopic surgery. Binary logistic regression was used to analyze risk factors including age, sex, body mass index, time from injury to surgery (≥3 or <3 months), mechanism of injury (contact or noncontact), side-to-side laxity, pivot-shift grade, medial and lateral tibial/meniscal slope, location of bone contusion, mechanical axis angle, and lateral femoral condyle (LFC) ratio. The receiver operating characteristic curve and area under the curve were also evaluated. Results: Ramp lesions were identified in 112 patients (30.9%). The risk for ramp lesions increased with steeper medial tibial and meniscal slopes, higher knee laxity, and an increased LFC ratio. Comparing the final performance of all models, the random forest model yielded the best performance (area under the curve: 0.944), although there were no significant differences among the models (P >.05). The cut-off values for the presence of ramp lesions on receiver operating characteristic analysis were as follows: medial tibial slope >5.5° (P <.001), medial meniscal slope >5.0° (P <.001), and LFC ratio >71.3% (P =.033). Conclusion: Steep medial tibial and meniscal slopes, an increased LFC ratio, and higher knee rotatory laxity were observed risk factors for ramp lesions in patients with an ACL injury. The prediction model of this study could be used as a supplementary diagnostic tool for ramp lesions in ACL-injured knees. In general, care should be taken in patients with ramp lesions and its risk factors during ACL reconstruction. [ABSTRACT FROM AUTHOR]

Background: Although several factors are associated with anterior cruciate ligament (ACL) rerupture, the effect of anatomic factors associated with ACL rupture on ACL rerupture development has not been evaluated. Purpose: To determine individual anatomic parameters independently associated with ACL rerupture and the diagnostic values of these parameters. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 91 male patients with ACL rerupture and 182 age-, sex-, body mass index–, and side dominance–matched patients without rerupture who underwent ACL reconstruction with a 5-year follow-up were included. In all, 35 parameters that were previously defined as risk factors for primary ACL rupture were compared between the 2 groups. Uni- and multivariate logistic regression models were created to evaluate independently associated factors. Receiver operating characteristic curve analysis was performed for independently associated parameters to predict sensitivity, specificity, and cutoff values. Results: The mean ± standard deviation age of patients at the time of index surgery was 26.5 ± 6.7 years. Notch shape index (P =.014), tibial proximal anteroposterior (AP) distance (TPAPD) (P <.001), lateral femoral condylar AP distance (LCAPD)/TPAPD ratio (P <.001), medial meniscal cartilage bone height (P <.001), and lateral meniscal bone angle (P =.004) were found to be significantly different between the 2 groups. Only the LCAPD/TPAPD ratio (odds ratio, 2.713; 95% CI, 1.998-5.480; P <.001) was found to be independently associated with ACL rerupture development. The LCAPD/TPAPD ratio revealed 78.9% sensitivity and 75.5% specificity (area under the curve, 0.815; 95% CI, 0.760-0.870) for values above 1.52. Conclusion: The LCAPD/TPAPD ratio can be used to distinguish patients who are at risk of developing ACL rerupture from patients who are not. In the clinical practice, findings of this study may help to develop surgical and nonsurgical preventive strategies in ACL rerupture development. [ABSTRACT FROM AUTHOR]

Background: Interest in the role of lateral extra-articular tenodesis (LET) in preventing rotatory instability and the pivot-shift phenomenon after anterior cruciate ligament reconstruction (ACLR) has been recently renewed. Nevertheless, there is still concern about overconstraint of the lateral compartment of the knee and the risk of subsequent osteoarthritis (OA). Purpose: The purpose of this retrospective study was to compare long-term subjective and objective outcomes and the rate of OA development between patients undergoing isolated ACLR (iACLR) with a hamstring tendon autograft and those with a combined Arnold-Coker modification of the McIntosh extra-articular procedure. Risk factors for long-term OA were evaluated. Study Design: Cohort study; Level of evidence, 3. Methods: The study included 165 consecutive patients treated at a single center by ACLR. A total of 86 patients underwent iACLR (iACLR group) and 79 received combined intra- and extra-articular reconstruction (ACLR+LET). The International Knee Documentation Committee (IKDC), Lysholm, and Tegner activity scores were administered. Knee stability was tested through the Lachman test, the pivot-shift test, and the KT-1000 knee arthrometer test. A positive pivot-shift test (++/+++), laxity on the KT-1000, and referred giving-way episodes or revision ACLR were considered failures. Radiographic results were assessed according to the Fairbank, IKDC, and Kellgren-Lawrence scales. Radiographic evaluation included both the overall tibiofemoral joint and the medial and lateral compartment separately. A univariate and a multivariate logistic regression with penalized maximum likelihood was used to identify risks factors associated with long-term OA. Results: The mean follow-up was 15.7 years. There were no statistically significant differences in subjective scores between the 2 groups. A side-to-side difference >5 mm on the KT-1000 arthrometer evaluation was found in 8 patients in the iACLR group and in 1 patient in the ACLR+LET group (P =.01). Nine cases of failure were found in the iACLR group and only 1 case was found in the ACLR+LET group (P =.0093). Patients in the iACLR group had a significantly higher OA grades than those in the ACLR+LET group for the overall tibiofemoral joint and the lateral compartment of the knee. No differences were found in the medial compartment. A higher level of lateral compartment OA was found in patients who received partial lateral meniscectomy in the iACLR group compared with those in the ACLR+LET group. Univariate and multivariate analysis results demonstrated that meniscectomy was the most significant factor for long-term OA development. Conclusion: A significantly higher risk of long-term OA was found with iACLR than with ACLR combined with the Arnold-Coker modification of the McIntosh extra-articular procedure. Knees with combined ACLR also had a significantly lower OA grade after partial lateral meniscectomy. Additionally, those undergoing combined ACLR had better knee stability and lower graft rupture rates at the long-term follow-up. Partial meniscectomy was the main risk factor negatively associated with OA changes. [ABSTRACT FROM AUTHOR]

Background: The incidence of meniscocapsular junction tears of the medial meniscus posterior horn, known as ramp lesions, is reported to be 9.3% to 23.9%. However, these lesions are not consistently diagnosed with routine arthroscopic exploration and magnetic resonance imaging (MRI). Purpose: To determine risk factors associated with ramp lesions in anterior cruciate ligament–injured knees. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 275 patients undergoing anterior cruciate ligament reconstruction between June 2011 and March 2019 were included in this study. Exclusion criteria were revisions, fracture histories, and multiple-ligament injuries other than medial collateral ligament injury. Patients were divided into 2 groups, those with and without ramp lesions according to arthroscopic diagnosis. Binary logistic regression was used to analyze risk factors: age, sex, body mass index, time from injury to surgery (<3 or ≥3 months), mechanism of injury (contact/noncontact), Segond fracture, side-to-side laxity, location of bone contusion, medial and lateral tibial/meniscal slope, and mechanical axis angle. Receiver operating characteristic curves and area under the curve were evaluated. A prediction model was developed by multivariable regression with generalized estimating equations. Results: Overall, 95 patients (34.5%) were confirmed as having a ramp lesion. The sensitivity of MRI for ramp lesions was 85.3%, and specificity was 78.3%. Significant risk factors for ramp lesion were as follows: posterior medial tibial plateau bone contusion on MRI (odds ratio [OR], 4.201; 95% CI, 2.081-8.482; P <.001), ≥3 months from injury (OR, 4.818; 95% CI, 2.158-10.757; P <.001), varus knee >3° (OR, 2.339; 95% CI, 1.048-5.217; P =.038), steeper medial tibial slope (OR, 1.289; 95% CI, 1.002-1.66; P =.049) and meniscal slope (OR, 1.464; 95% CI, 1.137-1.884; P =.003), and gradual lateral tibial slope (OR, 0.775; 95% CI, 0.657-0.914; P =.002). The area under the curve for the prediction model developed by logistic regression was 0.779 (sensitivity, 75.8%; specificity, 71.7%; P <.001) for ramp lesions. Conclusion: Care should be taken with patients who have significant risk factors for ramp lesions, including bone contusion at the posterior medial tibial plateau, chronic injury, steeper medial tibial and meniscal slope, gradual lateral tibial slope, and varus knee >3°. [ABSTRACT FROM AUTHOR]

Background: The lateral meniscus posterior root (LMPR) lesion further decreases dynamic knee stability after anterior cruciate ligament (ACL) injury owing to the loss of the "wedge effect" maintained by the posterior horn of the lateral meniscus. However, the effect of LMPR lesions on the static tibiofemoral relationship in extension after ACL injuries is not determined. Purpose: To (1) determine the effect of LMPR lesions on anterior tibial subluxation of the lateral compartment (ATSLC) in extension in patients with ACL injuries and to (2) identify the LMPR-related factors associated with excessive ATSLC in extension. Study Design: Cohort study; Level of evidence, 3. Methods: Between January 2015 and December 2017, 405 consecutive patients with diagnosed ACL injuries who underwent primary ACL reconstructions were retrospectively reviewed. Among them, 45 patients with combined ACL injuries and LMPR lesions (ACL+LMPR group) and 51 patients with isolated ACL injuries (ACL group) were identified. Values of ATSLC in extension were measured on preoperative supine magnetic resonance imaging and classified into high grade (≥6 mm) and low grade (<6 mm). The mean ATSLC in extension and the proportion of patients with high-grade ATSLC in extension were compared between the groups by univariate analysis. In the ACL+LMPR group, predictors of high-grade ATSLC in extension—including age, sex, body mass index, affected side, cause of injury, period from injury (<12 or ≥12 weeks), LMPR lesion pattern (radial tear or root avulsion), and meniscofemoral ligament integrity (intact or impaired)—were assessed by univariate analysis and multivariate logistic regression analysis. Results: The mean ATSLC in extension in the ACL+LMPR group was significantly greater than that in the ACL group (5.6 mm vs 3.1 mm; P =.001). The proportion of patients with high-grade ATSLC in extension in the ACL+LMPR group was also significantly larger than that in the ACL group (44.4% vs 15.7%; P =.002). In addition, the root avulsion (instead of radial tear) (odds ratio, 28.750; 95% CI, 2.344-352.549; P =.009) and the period from injury ≥12 weeks (odds ratio, 17.095; 95% CI, 1.207-242.101; P =.036) were determined to be the 2 independent predictors of high-grade ATSLC in extension. However, age, sex, body mass index, affected side, cause of injury, and meniscofemoral ligament integrity were not. Conclusion: After ACL injuries, concomitant LMPR lesion further increased ATSLC in extension. Chronic LMPR avulsion was associated with high-grade ATSLC in extension. [ABSTRACT FROM AUTHOR]

Background: The patellar tendon is often considered the "gold standard" graft for reducing the risk of graft rupture after anterior cruciate ligament (ACL) reconstruction. However, its use may also be associated with an increased risk of injury to the contralateral ACL. Purpose: To clarify the association between graft choice and the risk of revision and contralateral ACL reconstruction. Study Design: Cohort study; Level of evidence, 2. Methods: Prospective data captured by the New Zealand ACL Registry between April 2014 and December 2018 were reviewed. All primary ACL reconstructions performed using either a hamstring tendon or patellar tendon autograft were included. Cox regression survival analysis adjusting for patient factors was performed to compare the risk of revision and contralateral ACL reconstruction between the hamstring tendon graft and the patellar tendon graft. Results: A total of 7155 primary ACL reconstructions were reviewed, of which 5563 (77.7%) were performed using a hamstring tendon graft and 1592 (22.3%) were performed using a patellar tendon graft. Patients with a hamstring tendon graft had a revision rate of 2.7% compared with 1.3% in patients with a patellar tendon graft (adjusted hazard ratio [HR], 2.51; 95% CI, 1.55-4.06; P <.001). The patellar tendon graft was associated with an increased risk of contralateral ACL reconstruction compared with the hamstring tendon graft (adjusted HR, 1.91; 95% CI, 1.15-3.16; P =.012). The number needed to treat (NNT) with a patellar tendon graft to prevent 1 revision was 73.6. However, the NNT with a hamstring tendon graft to prevent 1 contralateral reconstruction was 116.3. Conclusion: Use of a patellar tendon graft reduced the risk of graft rupture but was associated with an increased risk of injury to the contralateral ACL. Adequate rehabilitation and informed decision making on return to activity and injury prevention measures may be important in preventing subsequent injury to the healthy knee. [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) tears are associated with the development of knee osteoarthritis despite ACL reconstruction surgery. However, little evidence is available to determine which patients will develop symptomatic knee osteoarthritis. Purpose: To determine if preoperative outcome measures—KOOS (Knee injury and Osteoarthritis Outcome Score) and SF-36 (36-item Short Form Health Survey)—were associated with the development of a symptomatic knee 7 years after ACL reconstruction. A secondary goal was to examine the relationship between imaging evidence of knee osteoarthritis and development of knee pain. Study Design: Case-control study; Level of evidence, 3. Methods: Prospectively collected data from 72 patients were reviewed with 7-year follow-up after unilateral ACL reconstruction. Patients were divided into symptomatic and asymptomatic groups based on the previously defined KOOS pain ≤72. Demographic variables and preoperative KOOS and SF-36 scores were compared between groups. Radiographic and magnetic resonance imaging data were used to evaluate differences in joint space width, Osteoarthritis Research Society International radiographic score, and the Whole-Organ Magnetic Resonance Imaging Score between groups. Univariate and multivariate analyses were performed to identify potential predictors of pain at 7-year follow-up. Wilcoxon sum rank and t tests were used to compare imaging findings between the symptomatic and asymptomatic patients at 7 years. Results: According to KOOS pain, 7 of the 72 patients available at 7-year follow-up formed the symptomatic group. No differences were found between groups in regard to demographic variables or intraoperative findings. In multivariate analysis, lower preoperative scores for KOOS sports/recreation (P = .005) and SF-36 mental health (P = .025) were associated with a painful knee at 7 years, with increased odds of 82% and 68% per 10-unit decrease, respectively. The Whole-Organ Magnetic Resonance Imaging Score at 7 years showed evidence of osteoarthritic changes in the symptomatic group as compared with the asymptomatic group (P = .047). However, there were no significant differences in the Osteoarthritis Research Society International radiographic score (P = .051) or joint space width (P = .488) between groups. Conclusion: Lower preoperative KOOS and SF-36 scores were associated with those patients who developed symptomatic knee osteoarthritis 7 years after ACL reconstruction. [ABSTRACT FROM AUTHOR]