Patient-Reported Knee Function and Return-to-Sport Rates After Nonsurgical and Surgical Treatment of an Acute Anterior Cruciate Ligament Injury: Results From the NACOX Prospective Cohort Study.

BACKGROUND: The best treatment for acute anterior cruciate ligament (ACL) injuries (surgical or nonsurgical) remains uncertain, particularly regarding return to sport (RTS) and knee function.

PURPOSE: To compare patient-reported knee function (International Knee Documentation Committee Subjective Knee Form [IKDC-SKF]) and RTS between non-ACL reconstruction (ACLR) and ACLR treatment strategies 24 months after ACL injury or reconstruction and identify predictors of these outcomes.

METHODS: From the NACOX multicenter cohort, 272 patients (mean age, 25.5 years; 95% CI, 24.6-26.3 years; 52% females) with acute ACL injuries were followed for 24 months after ACL injury or ACLR. Treatment (non-ACLR vs ACLR) was determined via shared decision-making in routine practice. IKDC-SKF scores were collected at 3, 6, 12, and 24 months and analyzed using a linear mixed-effects model adjusted for age, sex, preinjury activity level, and new serious knee injury. RTS was defined as return to preinjury Tegner level or higher. Risk factors for not returning to sport were evaluated using log-binomial regression.

RESULTS: The ACLR group had higher preinjury Tegner levels (8 vs 6.5; P < .001) and was younger (24.2 vs 27.6 years; P < .001). No differences in IKDC-SKF scores were observed between non-ACLR and ACLR groups. IKDC-SKF scores improved over time for both groups (P < .001) but were negatively affected by new serious knee injury (P < .001), older age (P = .003), and female sex (P = .004). Overall, 75% of patients achieved RTS within 24 months (mean, 6.3 months; 95% CI, 5.6-7.0 months), with no difference between groups (72% non-ACLR vs 77% ACLR; P = .286). Patients without ACLR returned to sport earlier (3.5 months [95% CI, 2.8-4.2 months] vs 8.1 months [95% CI, 7.2-9.0 months]; P < .001). In patients aged 26 to 40 years, ACLR was associated with a 3.15-fold higher risk of not returning to sport at 24 months compared to the non-ACLR group (P = .015).

CONCLUSION: In this cohort of patients with ACL injury, both nonsurgical management and ACLR, determined through shared decision-making, resulted in comparable patient-reported knee function and RTS rates at 24 months, although the ACLR group was younger and had higher activity level. Non-ACLR treatment may therefore be a viable option for selected patients, particularly those who are older or have lower activity demands, to achieve satisfactory RTS outcomes. Older age (26-40 years) was associated with a higher risk of not returning to sport after ACLR, highlighting the importance of individualized treatment decisions.

STUDY DESIGN: Cohort study; Level of evidence, 2.