Clinical and Functional Results of 119 Patients With Knee Dislocations

Abstract

Objectives: To describe clinical results and functional outcomes of knee dislocations treated with a consistent strategy within our institution.

Design: Retrospective case series.

Setting: Level 1 trauma center.

Patients: One hundred nineteen patients were treated at one institution between 2000 and 2014 for knee dislocation.

Main outcome measurements: Knee range of motion, functional instability, and complications were recorded. Musculoskeletal Function Assessment (MFA) and Lysholm scores were obtained after minimum of 1 year.

Results: Sixty-three early complications were noted in 36 patients (32%), with an overall amputation rate of 9.2% (8 early and 3 late amputations). Of the patients who retained their limb, 4.5% reported instability. Open knee dislocations were associated with amputation (26% vs. 1.3%, P < 0.001). Popliteal arterial injuries were associated with more amputation (31% vs. 3.2%, P = 0 < 0.001), infection (37% vs. 8%, P = 0.002), and deep venous thrombosis (32% vs. 8.8%, P = 0.014). Patients with wound infection were more likely to develop heterotopic ossification (36% vs. 9.4%, P = 0.017) and less knee motion (77.5 vs. 117 degrees P = 0.049). Knee motion improved over time for all patients with a mean arc of 86 degrees at 3 months, 109 degrees at 6 months, and 115 degrees at 12 months. An Injury Severity Score of ≥20 was associated with less knee motion (97 vs. 121 degrees P = 0.029). Mean Lysholm score was 86.7, and mean MFA score was 35.7 after mean follow-up of 90 months and 82 months, respectively.

Conclusions: Few patients (4.5%) experienced functional instability. However, early complications occurred frequently (32%) as expected, particularly in patients with open injuries and/or arterial injury. Limitations in knee motion were associated with high Injury Severity Score, infection, and heterotopic ossification. Mean knee scores were good, consistent with reasonable knee function, although MFA scores suggest a lower level of generalized function.

Level of evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.