Poster 349: Outcomes Following ACL Reconstruction with Concomitant Meniscus Allograft Transplantation Versus Isolated ACL Reconstruction

Objectives: Meniscus allograft transplantation (MAT) is used in the setting of ACL reconstruction to restore proper arthrokinematics and load distribution for the meniscus deficient knee. Objective outcomes following ACL reconstruction with concomitant MAT in athletic populations are scarcely reported and highly variable. Thus, the purpose of this study was to compare patient outcomes using an objective functional performance battery, self-reported outcomes, and return to activity rates between individuals undergoing an ACL reconstruction with concomitant MAT and the outcomes of patients undergoing isolated ACL reconstruction. We hypothesized that patients in the ACL reconstruction with MAT group would exhibit lower performance on objective functional tests, delayed time to release to activity, and lower return to activity rates when compared to those undergoing isolated ACL reconstruction. Methods: A single surgeon ACL database (n = 1,431) was utilized to identify patients undergoing ACL reconstruction with concomitant MAT from 2014-2019. A comparison group undergoing an isolated ACL reconstruction were identified to serve as a known control. Baseline patient and surgical demographics data were collected. Patients completed an objective functional performance battery at the time of return to activity which included range of motion (ROM), single leg squat performance, single leg hop test performance, subjective function (International Knee Documentation Committee score (IKDC)), and psychological readiness (ACL Return to Sports After Injury scale (ACL-RSI). Between limb comparisons were assessed using limb symmetry indices (LSI). Injury surveillance was conducted for two-years and included the Single Assessment Numeric Evaluation (SANE), re-injury rates, complications, and current level of sports participation. Between group comparisons at time of return to activity and two years were analyzed using generalized linear models utilizing an a-priori alpha level of .05. Results: Forty-four patients were included in the ACL reconstruction with concomitant MAT group along with 45 in the isolated ACL reconstruction group (Figure 1). Baseline demographic differences existed between groups with the MAT group being significantly older ( P=.001), having a higher BMI ( P=.001), and a lower MARX score (p=.001) (Table 1). The MAT group had a significantly delayed release to activity timeline (10.8 ±3.2mo vs 7.8 ±1.8mo, P = .001) and reported significantly lower IKDC scores (82.4 ±13.8 vs 93.7 ±10.1, P = .001) and ACL-RSI scores (62.8 ±21.3 vs 80.3 ±9.7, P = .001) at time of release to activity (Table 2). Likewise, the MAT group had significantly greater flexion ROM deficits (6.4 ±5.6 deg. vs 3.0 ±2.6 deg., P = .011) and lower single-leg hop symmetry (90.2 ±12.3% vs 97.1 ±5.3%, P = .001). At two- year follow-up the MAT group also demonstrated a significantly lower return to activity rate (69.7% vs 95%, P=.001), lower rate of participation in Level 1 sports (9.1% vs 63.3%, P=.001), and lower SANE scores (80.9 ±16.1 vs 92.5 ±8.3, P = .001) (Table 3). No significant differences existed between groups for ACL graft re-injury rates. Conclusions: The majority of patients undergoing ACL reconstruction with concomitant MAT are able to return to at least level 3 sports at two years post-surgery with low risk of graft re-injury. Patients receiving a concomitant MAT exhibit lower return to sport rates, delayed time to release to activity, and lower subjective function compared to those undergoing an isolated ACL reconstruction. Clinicians should consider patient expectations, surgical demographics, functional outcomes, extended rehabilitation timelines, and lower return to activity rates when counseling patients return to activity following ACL reconstruction with MAT. [Table: see text][Table: see text][Table: see text]