Obese Patients Demonstrate Higher Failure Rates, Infection Rates, and Inferior Patient-Reported Outcomes Compared With Nonobese Patients Following Multiligamentous Knee Surgery

Abstract

Purpose

To examine outcomes following surgically treated multiligamentous knee injuries (MLKIs) in obese versus nonobese patients.

Methods

Patients who were surgically treated for MLKIs between 2008 and 2021 were included in this study. Patients were divided into 2 groups and classified as obese (body mass index ≥30) or nonobese. The following patient-reported outcome measures were collected: the visual analog scale for pain, the International Knee Documentation Committee subjective score, and the Lysholm knee scoring scale. Complications such as revision ligamentous reconstruction, conversion to total knee arthroplasty (TKA), infection, and arthrofibrosis were also documented.

Results

A total of 88 patients (88 knees; 43 obese, 45 nonobese) were included in the final analysis. The mean overall age was 34.3 ± 12.7 years (10-61 years), and there were 30 women and 58 men included in this study cohort. The mean follow-up for the patients who did not receive a revision or TKA was 9.2 years (range, 3.4-15.3 years). There were no differences seen between groups for age, sex, mechanism of injury, neurovascular status, concomitant injuries, frank knee dislocations, surgical staging, or external fixator application. However, the mean follow-up in the nonobese group was higher than in the obese group (9.7 vs 8.3 years, P = .003). The nonobese cohort had significantly more open injuries compared to the obese cohort (11.1% vs 2.3%, P = .05). Although there were no differences seen in conversion to TKA or arthrofibrosis, the obese cohort had a higher rate of ligament failure (30.2% vs 8.9%, P = .02) and infection (14% vs 2.2%, P = .05). Additionally, the obese cohort had worse visual analog scale for pain scores (4.4 vs 2.2, P = .002), lower International Knee Documentation Committee scores (50.3 vs 74.6, P < .001), and lower Lysholm scores (59.9 vs 80.6, P = .004) at final follow-up compared to the nonobese cohort.

Conclusions

Obese patients had significantly higher rates of ligament failure and infection rates, higher pain scores, and worse patient-reported outcomes than nonobese patients following surgically treated MLKIs.

Level of Evidence

Level III, retrospective cohort study.