Rehabilitation alone after ACL injury yields greater limb symmetry but lower knee related self-efficacy without limiting return to preinjury activity level.

Purpose: To compare patients treated with rehabilitation alone to those undergoing anterior cruciate ligament (ACL) reconstruction and rehabilitation with regard to recovery of muscle strength, return to knee-strenuous sport and patient-reported outcomes during the first 12 months of treatment.

Methods: This study is a prospective cohort study, based on data from a rehabilitation registry, Project ACL, Gothenburg, Sweden. Included patients were ≥15 years with a primary ACL injury and had completed four follow-ups under first year of treatment. Patients were divided into two groups, depending on treatment choice (1) rehabilitation alone (rehabilitation group), or (2) rehabilitation with ACL reconstruction (ACLR group). Absolute and symmetrical isokinetic muscle strength and patient reported outcomes were assessed using a predefined schedule. Analyses were adjusted for age at time of injury. Subanalyses were performed separately on muscle strength for female and male patients. Clinical relevance was assessed with Cohen's d.

Results: In total, 31 patients in the rehabilitation group and 359 patients in the ACLR group were included. The rehabilitation group reported significantly greater symmetrical strength at every follow-up, except 12-month follow-up for knee flexion, and better quality of life at 8 months. Female patients in the rehabilitation group were stronger in their injured limbs knee extension at 10-week, 4-month and 8-month follow-up as well as for the knee flexion at 10 weeks although no clinically relevant results. The ACLR group demonstrated significantly larger changes in limb symmetry from the 2- to 12-month follow-up, greater future knee self-efficacy at 10 weeks, 4- and 8-month follow-up, and higher level of physical activity compared with the rehabilitation group, both preinjury, and at the 8- and 12-month follow-ups.

Conclusion: Patients treated with rehabilitation alone recovered greater limb symmetry, while patients treated with ACLR had greater change in limb symmetry between 2 and 12 months after treatment. Patients in the ACLR group had higher future knee-related self-efficacy and were active at a higher level of physical activity at 8 and 12 months after treatment.

Level of evidence: Level II.