Femoral offset loss and internal arch restoration defect are correlated with intramedullary nail cut-out complications after pertrochanteric fractures: a case-control study.

BACKGROUND AND PURPOSE: In a previous study, we investigated the link between the femoral offset (FO) loss by trochanteric impaction (TI) and cut-out complication occurrence after pertrochanteric fractures. Three major factors are likely to drive to failure after intramedullary nailing (IN): fracture stability, reduction quality and osteosynthesis quality. We wanted to investigate the quality of the fracture reduction through the TI and the neck-shaft angle (NSA) measurement and correlate these parameters with the risk of mechanical failure occurrence.

MATERIALS AND

METHODS

It was a retrospective multicentric one case-one control match design study with age and gender randomization. The cases presented a mechanical failure of nailing: [Formula: see text] in percentage. Femoral rotation was taken into account, and all TI were rotation-corrected (TIcorrected). Rotation-corrected neck-shaft angles (NSAcorrected) were calculated. The neck-shaft angle gap between the fractured and the healthy sides (NSAgap) was a ratio: [Formula: see text] in percentage. The tip-apex distance (TAD) was measured. Absolute values of TIcorrected and NSAgap were analyzed.

RESULTS

Twenty-one cases and 21 controls were examined. The average TIcorrected rate was 30% for the cases and 11% for the controls (p = 0.007). A 13% TIcorrected threshold had maximum specificity and sensitivity, equal to 71%. The average TAD was 27 mm for cases and 19 mm for controls (p = 0.004). The average NSAgap rate was 7% for the case group and 4% for the control group (p = 0.009). The areas under the ROC curves for TIcorrected, TAD and NSAgap were 0.73, 0.73 and 0.66, respectively.

INTERPRETATION: Closed reduction and exclusive implantation of IN do not seem optimal in case of FO or NSA restoration failure after pertrochanteric fractures.

LEVEL OF EVIDENCE: Level III, case-control study.