Evaluating polymethylmethacrylate (PMMA) augmentation in cephalomedullary nail fixation of hip fractures: a step towards evidence-based patient selection criteria.

INTRODUCTION

Intertrochanteric (IT) hip fractures are increasingly common among older adults and are associated with significant morbidity and mortality. Cephalomedullary nailing is widely adopted for the treatment of intertrochanteric (IT) fractures; however, implant cut-out or cut-through (COCT) continues to be a significant complication. Polymethylmethacrylate (PMMA) augmentation has been introduced to mitigate this risk, though its use is associated with potential drawbacks including thermal necrosis and cement leakage into the joint or fracture site. Therefore, the aim of this study was to determine which patients are most likely to benefit from PMMA augmentation.

METHODS

We conducted a retrospective cohort study of patients who underwent short TFNA™ fixation for fragility IT hip fractures between January 2019 and December 2022 at a tertiary hospital in Singapore. Demographic, biochemical, radiological, and surgical data were collected. The primary outcome was implant COCT. Multivariate analysis was used to identify independent predictors of COCT.

RESULTS

Among 286 patients (median follow-up 12 months), implant COCT occurred in 16 (5.6%). Firth's regression showed higher neck-shaft angle increased COCT risk (aOR 1.09, p = 0.028), while PMMA augmentation (aOR 0.27, p = 0.054) and male sex (aOR 0.22, p = 0.085) were protective. Anterior cortical support and tip-apex distance were not significant on multivariate analysis. Median time to COCT was longer with cemented fixation (345 vs. 84 days, p = 0.011).

CONCLUSION

PMMA augmentation reduces the risk and delays the onset of implant COCT in TFNA™ fixation of fragility IT fractures. However, potential complications with PMMA highlight the need for selective use. Further research involving larger cohorts is needed to develop an evidence-based criteria for guiding PMMA augmentation in clinical practice.