Neutrophil-to-lymphocyte ratio in prediction of post-traumatic osteoarthritis following surgery of intra-articular ankle fracture.

PURPOSE: To investigate the prognostic value of neutrophil-to-lymphocyte ratio (NLR) in predicting post-traumatic osteoarthritis (PTOA) following surgical fixation of intra-articular ankle fractures.

METHODS

This retrospective cohort study included patients who underwent surgery for closed, intra-articular ankle fractures in a tertiary care center between January 2019 and December 2021, with a minimum follow-up of 3 years. NLR was calculated from routine blood tests within 24 hours post-injury. PTOA was diagnosed radiographically based on the Kellgren-Lawrence grading system. Multivariable logistic regression was employed to assess the independent predictive role of NLR after adjusting for covariates.

RESULTS

A total of 764 patients were included, including 455 (59.6%) males and 309 (40.4%) females, with a mean age of 43.9 ± 14.6 years. The restricted cubic spline (RCS) model demonstrated a nonlinear relationship between NLR and PTOA, with risk sharply rising above the 6.5 threshold. High-NLR patients (n = 159) also exhibited higher surgical complexity, increased bleeding, and more frequent emergency interventions, as compared with low-NLR group (n = 605). The risk of PTOA was 37.7% (60/159) and 19.5% (118/605) in both groups, respectively (P < 0.001). An NLR ≥ 6.5 was associated with a significantly increased risk of PTOA (adjusted OR = 2.299, 95% CI: 1.517-3.483, P < 0.001).

CONCLUSIONS

These findings suggest that elevated early post-injury NLR may be associated with the development of PTOA following ankle fracture surgery; however, given the single time-point assessment, further prospective studies with serial measurements are needed to clarify its role.