Association Between Anteromedial Portal Versus Tibial Tunnel Drilling and Meniscal Reoperation Risk Following Anterior Cruciate Ligament Reconstruction: A Cohort Study.

BACKGROUND: Anterior cruciate ligament reconstruction (ACLR) provides functional stability to an injured knee. While multiple techniques can be used to drill the femoral tunnel during ACLR, a single technique has yet to be proven as clinically superior. One marker of postoperative functional stability is subsequent meniscal tears; a lower risk of subsequent meniscal surgery could be expected with improved knee stability. PURPOSE: To determine if there is a meniscal protective effect when using an anteromedial portal (AMP) femoral tunnel drilling technique versus transtibial (TT) drilling. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Data from Kaiser Permanente's ACLR registry were used to identify patients who had a primary isolated ACLR between 2009 and 2018; those with previous surgery in the index knee and meniscal pathology at the time of ACLR were excluded. The exposure of interest was TT (n = 2711) versus AMP (n = 5172) drilling. Multivariable Cox proportional hazard regression was used to evaluate the risk of a subsequent ipsilateral meniscal reoperation with adjustment for age, sex, femoral fixation, and graft choice. We observed a shift in surgeon practice from the TT to AMP over the study time frame; therefore, the relationship between technique and surgeon experience on meniscal reoperation was evaluated using an interaction term in the model. RESULTS: At the 9-year follow-up, the crude cumulative meniscal reoperation probability for AMP procedures was 7.76%, while for TT it was 5.88%. After adjustment for covariates, we observed a higher risk for meniscal reoperation with AMP compared with TT (hazard ratio [HR], 1.53; 95% CI, 1.05-2.23). When stratifying by surgeon experience, this adverse association was observed for patients who had their procedure performed by surgeons with less AMP experience (no previous AMP ACLR: HR, 1.26; 95% CI, 0.84-1.91) while a protective association was observed for patients who had their procedure with more experienced surgeons (40 previous AMP ACLRs: HR, 0.34; 95% CI, 0.13-0.92). CONCLUSION: Drilling the femoral tunnel via the AMP was associated with a higher risk of subsequent meniscal surgery compared with TT drilling. However, when AMP drilling was used by surgeons experienced with the technique, a meniscal protective effect was observed.

The Incidence of Subsequent Meniscal Surgery Is Higher in the Anterior Cruciate Ligament-Reconstructed Knee Than in the Contralateral Knee.

BACKGROUND: A goal of anterior cruciate ligament (ACL) reconstruction is to provide a meniscal protective effect for the knee. PURPOSE: (1) To evaluate whether there was a different likelihood of subsequent meniscal surgery in the ACL-reconstructed knee or in the normal contralateral knee and (2) to compare the risk factors associated with subsequent meniscal surgery in the ACL-reconstructed knee and contralateral knee. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Using an integrated health care system's ACL reconstruction registry, patients undergoing primary ACL reconstruction, with no meniscal injury at the time of index surgery and a normal contralateral knee, were evaluated. Subsequent meniscal tears associated with ACL graft revision were excluded. Subsequent meniscal surgery in either knee was the outcome of interest. Sex, age, and graft type were assessed as potential risk factors. Survival analysis was used to compare meniscal surgery-free survival rates and to assess risk factors of subsequent meniscal surgery. RESULTS: Of 4087 patients, there were 32 (0.78%) patients who underwent subsequent meniscal surgery in the index knee and 9 (0.22%) in the contralateral knee. The meniscal surgery-free survival rate at 4 years was 99.08% (95% CI, 98.64%-99.37%) in the index knee and 99.65% (95% CI, 99.31%-99.82%) in the contralateral knee. There was a 3.73 (95% CI, 1.73-8.04; P < .001) higher risk of subsequent meniscal surgery in the index knee compared with the contralateral knee, or a 0.57% absolute risk difference. After adjustments, allografts (hazard ratio [HR], 5.06; 95% CI, 1.80-14.23; P = .002) and hamstring autografts (HR, 3.11; 95% CI, 1.06-9.10; P = .038) were risk factors for subsequent meniscal surgery in the index knee compared with bone-patellar tendon-bone (BPTB) autografts. CONCLUSION: After ACL reconstruction, the overall risk of subsequent meniscal surgery was low. However, the relative risk of subsequent meniscal surgery in the ACL-reconstructed knee was higher compared with the contralateral knee. Only graft type was found to be a risk factor for subsequent meniscal surgery in the ACL-reconstructed knee, with a higher risk for allografts and hamstring autografts compared with BPTB autografts.

A comparison of revision and rerupture rates of ACL reconstruction between autografts and allografts in the skeletally immature.

PURPOSE: Anterior cruciate ligament reconstructions (ACLRs) in skeletally immature patients are increasing. The purpose of this study is to describe the demographics, graft usage, revision, and re-operation rates in skeletally immature ACLRs in the Kaiser Permanente healthcare system. METHODS: Skeletally immature patients (<17.0 years old with open physes) were identified using the Kaiser Permanente ACLR registry. Multi-ligament reconstructions and physeal-sparing ACLRs were excluded. Aseptic revision and same-knee re-operation were the outcomes of interest. Exposure of interest was graft type; bone-patellar-tendon-bone (BPTB) autograft, hamstring autograft, and any type of allograft. Age, gender, body mass index (BMI), and race were evaluated as confounders. Cox proportional hazard models stratified by surgeon were used to analyse the risk of revision and re-operation. RESULTS: A total of 534 primary ACLR cases were evaluated with a mean follow-up of 2.9 years. The majority were hamstring autografts (n = 388, 72.7%), male (n = 339, 63.9%), and White (n = 232, 43.4%). Median age was 14.9 years, and median BMI was 21.9 kg/m(2). There were 44 (8.2%) aseptic revisions and 48 (9.0%) same-knee re-operations. The incidence rate for revision was BPTB autograft 5.5%, hamstring autograft 7.5%, and allograft 13.2%. After adjusting for confounders and surgeon clustering effect, the risk of aseptic revision and revision between allograft and hamstring autograft did not reach statistical significance. CONCLUSION: Graft selection differs in skeletally immature patients with a preponderance of surgeries being performed with hamstring tendon autografts. High revision rates were identified for all graft types used, though differences in revision rates across different graft types did not reach statistical significance. Surgeons should be aware of high rates of revision in this skeletally immature young population, although type of graft used did not appear to make a difference. LEVEL OF EVIDENCE: III.

Are meniscus and cartilage injuries related to time to anterior cruciate ligament reconstruction?

BACKGROUND: Functional instability after anterior cruciate ligament injury can be successfully treated with ligament reconstruction. However, the associated meniscus and cartilage lesions often cannot be repaired and may have long-term detrimental effects on knee function. PURPOSE: The authors used the large database within the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry to evaluate time to surgery, age, and gender as risk factors for meniscus and cartilage injury and associations with meniscus repair rates in patients. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A retrospective review of the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry was performed. The associations between time to surgery, age, and gender with meniscus and cartilage lesions and meniscus repair were analyzed using binary logistic regression modeling to calculate odds ratios (ORs) while adjusting for potential confounding variables. RESULTS: A total of 1252 patients met the inclusion criteria. The risk of medial meniscus injury increased only with time to surgery (6-12 months: OR = 1.81, 95% confidence internal [CI] 1.29-2.54, P = .001; and >12 months: OR = 2.19, 95% CI 1.58-3.02, P < .001). The risk of lateral meniscus injury decreased only with female gender (OR = 0.65, 95% CI 0.51-0.83, P = .001). The risk of cartilage injury increased with age (OR = 1.05 per year, 95% CI 1.04-1.07, P < .001) and time to surgery >12 months (OR = 1.57, 95% CI 1.12-2.20, P = .009), but decreased with female gender (OR = 0.71, 95% CI 0.54-0.92, P = .009). Medial meniscus repairs relative to medial meniscus injury decreased with increasing time to surgery (3-6 months: OR = 0.61, 95% CI 0.37-1.00, P = .050; and >12 months: OR = 0.41, 95% CI 0.25-0.67, P < .001) and increasing age (OR = 0.96 per year, 95% CI 0.94-0.98, P < .001). CONCLUSION: Increased risk of medial meniscus injury and decreased repair rate were strongly associated with increasing time to surgery. Increased risk of cartilage injury was associated with increasing age, increasing time to surgery, and male gender.

The effects of thermal capsulorrhaphy of medial parapatellar capsule on patellar lateral displacement.

BACKGROUND: The effectiveness of thermal shrinkage on the medial parapatellar capsule for treating recurrent patellar dislocation is controversial. One of reasons why it is still controversial is that the effectiveness is still qualitatively measured. The purpose of this study was to quantitatively determine the immediate effectiveness of the medial parapatellar capsule shrinkage as in clinical setting. METHODS: Nine cadaveric knees were used to collect lateral displacement data before and after medial shrinkage or open surgery. The force and displacement were recorded while a physician pressed the patella from the medial side to mimic the physical exam used in clinic. Ten healthy subjects were used to test the feasibility of the technique on patients and establish normal range of lateral displacement of the patella under a medial force. The force applied, the resulting displacement and the ratio of force over displacement were compared among four data groups (normal knees, cadaveric knees before medial shrinkage, after shrinkage and after open surgery). RESULTS: Displacements of the cadaveric knees both before and after thermal modification were similar to normal subjects, and the applied forces were significantly higher. No significant differences were found between before and after thermal modification groups. After open surgery, displacements were reduced significantly while applied forces were significantly higher. CONCLUSION: No immediate difference was found after thermal shrinkage of the medial parapatellar capsule. Open surgery immediately improved of the lateral stiffness of the knee capsule.