Initial external fixation after knee dislocation is associated with inferior outcomes following delayed multiligament reconstruction: a retrospective single-surgeon cohort study.

Abstract

Optimal initial immobilization after knee dislocation (KD) remains controversial, particularly whether knee-spanning external fixation (KSEF) contributes to long-term stiffness following multiligament knee reconstruction (MLKR). No prior study has directly compared outcomes based on initial immobilization method. This retrospective single-surgeon cohort study evaluated whether initial KSEF versus hinged knee bracing (HKB) was associated with differences in functional outcomes after delayed (>6 weeks) MLKR. We retrospectively reviewed skeletally mature patients with radiographically confirmed KD treated at a Level 1 trauma center from 2015 to 2023 who subsequently underwent delayed MLKR. Patients were categorized by initial immobilization method (KSEF vs HKB). Demographics, injury characteristics, and associated injuries were collected. The primary outcomes were the International Knee Documentation Committee (IKDC) score and included the modified Tegner-Lysholm Knee Score (MTLKS) and final knee flexion. A subgroup analysis excluding vascular injuries was performed to explore the influence of injury severity. Twenty knees in 19 patients met inclusion criteria (mean follow-up, 3.2 ± 2.1 years). Compared with patients treated initially with HKB (n = 12), those treated with KSEF (n = 8) demonstrated lower IKDC scores (mean difference -16.1; 95% CI -32.0 to -1.8), lower MTLKS (mean difference -20.5; 95% CI -35.4 to -5.4), and reduced knee flexion (mean difference -18.9°; 95% CI -32.1° to -6.2°). Similar associations persisted in the subgroup analysis excluding vascular injuries. Initial external fixation was associated with lower functional scores and decreased knee flexion after delayed MLKR. These findings are hypothesis-generating given the small sample size and confounding by injury severity.