Trimming the Fat: Does GLP-1 Receptor Agonist Therapy Impact Clinical and Functional Results After Tibial Plateau Fracture Fixation?

Abstract

Abstract: This study evaluated the impact of prolonged glucagon-like peptide-1 (GLP-1) receptor agonist use on postoperative outcomes, including radiographic posttraumatic osteoarthritis (PTOA), fracture nonunion, and final knee range of motion (ROM)-following operative management of tibial plateau fractures across multiple body mass index (BMI) strata. A retrospective cohort study was conducted at an urban academic institution, including patients who underwent surgical fixation for tibial plateau fractures between 2016 and 2024, with a ≥ 6 months follow-up. The GLP-1 cohort consisted of patients with documented long-term GLP-1 use pre- and postoperatively. GLP-1 users (Group A, n = 24) were compared with three non-GLP-1 cohorts stratified by BMI: Group B (BMI: 18.5-25, n = 150), Group C (BMI: 25-30, n = 150), and Group D (BMI ≥ 30, n = 100). Outcomes included Kellgren-Lawrence osteoarthritis grade, postreduction fracture angulation, articular step-off, Charlson Comorbidity Index (CCI), fracture complications (infection, nonunion, PTOA, revision surgery), and final knee flexion ROM. Statistical analyses used SPSS Statistics version 29.0 (IBM Corp., Armonk, New York, United States) with analysis of variance and chi-square tests. Mean follow-up was 28.83 months. Baseline age, CCI, fracture angulation, and step-off were comparable between groups. Preinjury osteoarthritis severity was higher in Group A (0.96 ± 0.88) than in Groups B (0.68 ± 0.86), C (0.54 ± 0.75), and D (0.78 ± 0.74; p < 0.001). Radiographic PTOA incidence was highest in Group D (32%, p < 0.01), while Group A rates were comparable to Groups B and C (p is approximately 0.62). Final knee flexion ROM differed significantly (p < 0.01), with Group D showing the lowest mobility (119.08 ± 16.47 degrees). Nonunion rates were significantly higher in Group A (p < 0.01). Among obese patients, GLP-1 receptor agonist use was associated with a lower incidence of PTOA and preserved knee ROM compared with untreated obese individuals, with outcomes similar to nonobese patients. However, GLP-1 use was also linked to increased nonunion rates. These findings suggest that while GLP-1 therapy may mitigate obesity-related joint degeneration, it may also challenge fracture healing.