Primary ACL Repair and Reconstruction in Isolated ACL Ruptures: Forgotten Joint Scores and the Association Between Residual Laxity and Joint Awareness

Background: Primary anterior cruciate ligament (ACL) repair has recently reemerged as a treatment option for carefully selected proximal ACL tears. However, evidence regarding patient-reported joint awareness and the relationship between postoperative laxity and joint awareness remains limited. Purpose: To compare joint awareness, clinical outcomes, and postoperative laxity between primary ACL repair and hamstring tendon autograft reconstruction in carefully selected patients with isolated ACL rupture, and to explore the association between residual laxity and postoperative joint awareness. Study Design: Cohort study; Level of evidence, 3. Methods: This retrospective cohort study included 85 patients with isolated ACL rupture treated with either primary ACL repair (n = 26) or hamstring autograft reconstruction (n = 59), with a minimum follow-up of 24 months. Clinical outcomes, including visual analog scale score, Lysholm score, International Knee Documentation Committee (IKDC) score, Tegner activity scale score, postoperative knee laxity, return to sport, and rerupture rates, were evaluated. The authors also used the Forgotten Joint Score-12 (FJS-12), a measure of joint awareness, to evaluate patients. A higher score reflects lower joint awareness, suggesting function more similar to a native knee. Multivariable regression analyses were performed to evaluate variables associated with postoperative FJS-12 values. Results: No differences were observed between groups in postoperative Lysholm, IKDC, and Tegner activity scale scores; Lachman- and pivot-shift–assessed postoperative laxity; and return-to-sport rates. However, postoperative FJS-12 values were significantly higher in the repair group compared with the reconstruction group (87.0 ± 15.0 vs 77.5 ± 14.2; mean difference, 9.5 points [95% CI, 2.8-16.3]; P = .006), corresponding to a moderate effect size (Cohen d = 0.66). Secondary exploratory regression analyses demonstrated that residual postoperative laxity was associated with lower postoperative FJS-12 values in both Lachman- and pivot-shift–based models ( R 2 = 0.649 and 0.680, respectively; P < .001 for both). Conclusion: In carefully selected patients with proximal ACL tears and adequate tissue quality, no significant between-group differences were detected in conventional clinical outcomes, postoperative laxity, return-to-sport rates, or rerupture rates between primary ACL repair and reconstruction. Primary ACL repair was associated with higher postoperative FJS-12 values at short- to midterm follow-up, suggesting function more similar to that of a native knee. Residual postoperative laxity was associated with lower FJS-12 values in secondary exploratory analyses.