Laterally protruded cephalomedullary nail lag screws are a source of consistent thigh pain after pertrochanteric fracture.

OBJECTIVES: To assess the correlation between the amount of proximal screw lateralization and clinical symptoms in patients treated with a cephalomedullary nail after a pertrochanteric fracture.

DESIGN: Retrospective study.

SETTING: Level 1 trauma center.

PATIENT SELECTION CRITERIA: Patients operated for a pertrochanteric fracture (OTA/AO A1, A2, A3) between 2019 and 2022 and treated with a cephalomedullary nail were included.

OUTCOME MEASURES AND COMPARISONS: Three measurements were evaluated: D1- distance between the most laterally prominent point of the lag screw and the line tangent to the greater trochanter, D2- distance between the lateral femoral cortex and the most laterally prominent point of the lag screw and D3-distance between the point where the lag screw emerges at the lateral edge of the femur shaft and the skin's surface. Clinical scores and information regarding lateral thigh pain were obtained and a correlation analysis was performed.

RESULTS: Mean age of the study cohort (n=134) was 77.9 ± 12.3 years. Patients with categorical protrusion (considered present in cases where the distance between the lateral tip of the lag screw and the lateral border of the greater trochanter was ≥ 0.2mm) had significantly higher rates of lateral thigh pain (p=0.007) and discomfort while lying on the side (p=0.032) compared to those without protrusion. Correlation analyses showed a positive correlation between measurements D1 and D2 and lateral thigh pain (r=0.324 and r=0.334 respectively, p<0.001) and a negative correlation between D3 and lateral thigh pain (r=-0.286, p=0.001). Regression analysis showed that higher D1 and D2 distances and shorter D3 distances are risk factors for lateral thigh pain (p=0.001, 0.001 and 0.002 respectively).

CONCLUSIONS: Increasing lateral protrusion of the lag screw leads to significantly greater clinical complaints and lateral hip pain in patients treated with a cephalomedullary nail. Patients with lower distance between the lateral femoral wall and the skin are at higher risk of lateral pain.

LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.