Background Revision anterior cruciate ligament (ACL) reconstruction has worse outcomes than primary reconstructions. Predictors for these worse outcomes are not known. The Multicenter ACL Revision Study (MARS) Group was developed to perform a multisurgeon, multicenter prospective longitudinal study to obtain sufficient subjects to allow multivariable analysis to determine predictors of clinical outcome. Purpose To describe the formation of MARS and provide descriptive analysis of patient demographics and clinical features for the initial 460 enrolled patients to date in this prospective cohort. Study Design Cross-sectional study; Level of evidence, 2. Methods After training and institutional review board approval, surgeons began enrolling patients undergoing revision ACL reconstruction, recording patient demographics, previous ACL reconstruction methods, intra-articular injuries, and current revision techniques. Enrolled subjects completed a questionnaire consisting of validated patient-based outcome measures. Results As of April 1, 2009, 87 surgeons have enrolled a total of 460 patients (57% men; median age, 26 years). For 89%, the reconstruction was the first revision. Mode of failure as deemed by the revising surgeon was traumatic (32%), technical (24%), biologic (7%), combination (37%), infection (<1%), and no response (<1%). Previous graft present at the time of injury was 70% autograft, 27% allograft, 2% combination, and 1% unknown. Sixty-two percent were more than 2 years removed from their last reconstruction. Graft choice for revision ACL reconstruction was 45% autograft, 54% allograft, and more than 1% both allograft and autograft. Meniscus and/or chondral damage was found in 90% of patients. Conclusion The MARS Group has been able to quickly accumulate the largest revision ACL reconstruction cohort reported to date. Traumatic reinjury is deemed by surgeons to be the most common single mode of failure, but a combination of factors represents the most common mode of failure. Allograft graft choice is more common in the revision setting than autograft. Concomitant knee injury is extremely common in this population.

Background Knees undergoing revision ACL reconstruction (rACLR) have a high prevalence of articular cartilage lesions. Hypothesis The purpose of this study was to test the hypothesis that the prevalence of chondrosis at the time of rACLR is associated with meniscus status and lower extremity alignment. Study design Cross sectional study. Methods Data from the prospective Multicenter ACL Revision Study (MARS) cohort was reviewed to identify patients with pre-operative lower extremity alignment films. Lower extremity alignment was defined by the weight bearing line (WBL) as a percentage of the tibial plateau width, while the chondral and meniscal status of each weight bearing compartment was recorded at the time of surgery. Multivariable proportional odds models were constructed and adjusted for relevant factors in order to examine which risk factors were independently associated with the degree of medial and lateral compartment chondrosis. Results The cohort included 246 patients with lower extremity alignment films at the time of rACLR. Average (SD) patient age was 26.9 (9.5) years with a BMI of 26.4 (4.6). The medial compartment had more chondrosis (Grade 2/3: 42%, Grade 4: 6.5%) than the lateral compartment (Grade 2/3: 26%, Grade 4: 6.5%). Disruption of the meniscus was noted in 35% of patients on the medial side and 16% in the lateral side. The average (SD) WBL was measured to be 0.43 (0.13). Medial compartment chondrosis was associated with BMI (p=0.025), alignment (p=0.002), and medial meniscus status (p=0.001). None of the knees with the WBL lateral to 0.625 had Grade 4 chondrosis in the medial compartment. Lateral compartment chondrosis was significantly associated with age (p=0.013) and lateral meniscus status (p<0.001). Subjects with ‘intact’ menisci were found to decrease their odds of having chondrosis by 64–84%. Conclusions The status of articular cartilage in the tibiofemoral compartments at the time of rACLR is related to meniscal status. Lower extremity alignment and BMI are associated with medial compartment chondrosis. Clinical relevance Providers and patients should be aware of the association of meniscal integrity, alignment and BMI with chondrosis at the time of rACLR. Further research into the potential benefits of interventions to optimize these parameters is warranted.

Background Meniscal allograft transplantation (MAT) is considered a viable surgical treatment option in the symptomatic, postmeniscectomy knee and as a concomitant procedure with ACL revision and articular cartilage repair. Although promising outcomes have recently been reported in active and athletic populations, MAT has not been well-studied in the high-demand military population. Questions/purposes (1) What proportion of active-duty military patients who underwent MAT returned to full, unrestricted duty? (2) What demographic and surgical variables, if any, correlated with return to full, unrestricted duty? Methods Between 2005 and 2015, three fellowship-trained sports surgeons (TMD, SJS, BDO) performed 110 MAT procedures in active-duty military patients, of which 95% (104 patients) were available for follow-up at a minimum 2 years (mean 2.8 ± SD 1.1 year). During the study period, indications for MAT generally included unicompartmental pain and swelling in a postmeniscectomized knee and as a concomitant procedure when a meniscal-deficient compartment was associated with either an ACL revision reconstruction or cartilage repair. Demographic and surgical variables were collected and analyzed. The primary endpoints were the decision for permanent profile activity restrictions and military duty termination by a medical board. The term “medical board” implies termination of military service because of medical reasons. We elected to set statistical significance at p < 0.001 to reduce the potential for spurious statistical findings in the setting of a relatively small sample size. Results Forty-six percent (48 of 104) of eligible patients had permanent profile activity restrictions and 50% (52 of 104) eventually had their military duty terminated by a military board. Only 20% (21 of 104) had neither permanent profile activity restrictions nor medical-board termination and were subsequently able to return to full duty, and only 13% (13 of 104) continued unrestricted military service beyond 2 years after surgery. Age, gender, tobacco use, and BMI did not correlate with return to full duty. Combat arms soldiers were less likely to have permanent profile activity restrictions (odds ratio 4.76 [95% confidence interval 1.93 to 11.8]; p = 0.001) and were more likely to return to full duty than soldiers in support roles (OR 0.24 [95% CI 0.09 to 0.65]; p = 0.005), although these findings did not reach statistical significance. Officers were more likely to return to full duty than enlisted soldiers at more than 2 years after surgery (OR 17.44 [95% CI 4.56 to 66.65]; p < 0.001). No surgical variables correlated with return-to-duty endpoints. Conclusions Surgeons should be aware of the low likelihood of return to military duty at more than 2 years after MAT and counsel patients accordingly. Based on this study, MAT does not appear to be compatible with continued unrestricted military duty for most patients. Level of Evidence IV, therapeutic study.