Partial Controlled Early Postoperative Weightbearing Versus Nonweightbearing After Reconstruction of the Fibular (Lateral) Collateral Ligament: A Randomized Controlled Trial and Equivalence Analysis.

Background: While early weightbearing protocols have been advocated after anterior cruciate ligament (ACL) reconstruction, early weightbearing after fibular (lateral) collateral ligament reconstruction has not been well defined.

Purpose: (1) To determine if early partial controlled weightbearing after fibular collateral ligament (FCL) reconstruction resulted in an objective difference in laxity on varus stress radiographs at postoperative 6 months as compared with nonweightbearing, and (2) to determine if there was a difference in pain, edema, range of motion, and subjective patient-reported outcomes between these groups at 3 time points.

Study Design: Randomized controlled trial; Level of evidence, 1.

Methods: Patients were prospectively enrolled from January 2014 to April 2017. Patients who underwent isolated FCL reconstruction or combined ACL and FCL reconstructions were included in this study. Patients were randomly assigned to either a control group (nonweightbearing for 6 weeks) or a treatment group (partial controlled weightbearing at 40% body weight with crutches for 6 weeks). Patient-related data, including knee pain, edema, and range of motion, were collected for all patients at postoperative day 1, 6 weeks, and 6 months. Subjective outcomes were collected preoperatively and at 6 months postoperatively. The primary objective endpoint was varus stability, evaluated by bilateral varus stress radiographs obtained preoperatively and at 6 months postoperatively.

Results: Thirty-nine patients were enrolled in the study, with 6-month follow-up obtained for 36 (92%). There was a significant improvement between the preoperative side-to-side difference (SSD) (2.4 ± 1.0) and postoperative SSD (0.2 ± 1.0) for lateral compartment laxity on varus stress radiographs among all patients ( P < .001). Clinical and statistical equivalence was found between groups in terms of SSD on varus stress radiographs ( P < .001). The SSD in knee edema was significantly lower in the partial early weightbearing group (beta = -0.6 cm, P = .001), but there were no significant group differences in knee pain, flexion, or extension. All patients demonstrated significant improvements in subjective outcome scores between the preoperative and 6-month postoperative conditions ( P < .001 for every score measured).

Conclusion: Clinical and statistical equivalence was found at postoperative 6 months between the early partial weightbearing and nonweightbearing groups among patients undergoing either an isolated FCL reconstruction or a combined ACL and FCL reconstruction. There were no significant differences observed between the groups regarding knee stability, pain, swelling, range of motion, or subjective outcomes. Given these findings, the authors recommend early partial weightbearing after isolated FCL reconstruction or combined ACL and FCL reconstruction.