Lag Screw Exchange for Impinging Lateral Hardware Following Intramedullary Nailing of Intertrochanteric Hip Fractures - A Case Series Demonstrating Efficacy.

Background: This study aimed to demonstrate the feasibility of lag screw exchange for painful lateral soft tissue impingement in patients initially treated with cephalomedullary nailing (CMN) for an intertrochanteric hip fracture.

Methods: Ten patients initially treated with CMN for unstable intertrochanteric fractures presenting with persistent pain and radiographic evidence of lag screw lateral migration were treated with exchange of original screw with shorter lag screw buried in the lateral cortex to prevent impingement. Patients were evaluated for resolution of pain and achievement of pre-fracture ambulatory status at 6 months post-operatively.

Results: Average age was 71.5 years (range: 62-88). Average length of follow-up was 24.9 months. All patients were female, with an average Charlson Comorbidity Index of 1.0 (0-3) and average Body Mass Index of 22.2 (16.0-31.1). Five of ten patients (50.0%) were treated with a cortisone injection in the trochanteric bursa prior to screw exchange with temporary pain relief. Five (50.0%) patients presented with limited range of hip motion. Five (50.0%) had history of prior or current bisphosphonate use. Average lag screw prominence was noted to be 12.2mm (7.9-17.6mm) on radiographic evaluation. Screw exchange was performed at an average of 18.6 months (5.4-44.9 months) following the index procedure. Average operating time of the screw exchange procedure was 45.3 minutes (34-69 minutes) and blood loss was <50mL in all cases. Replacement lag screws were an average of 16.0mm (10-25mm) shorter than the initial screw. All patients achieved complete or significant resolution of lateral thigh pain, and nine (90%) returned to pre-fracture ambulatory status by eight weeks after screw exchange. All patients remained pain free at six months after screw exchange.

Conclusion: Lag screw exchange is a efficacious method to address the mechanical irritation of laterally protruding lag screws following IT hip fracture, while also prophylaxing against subsequent femoral neck fractures. Level of Evidence: IV.