Complications of cement-augmented dynamic hip screws in unstable type intertrochanteric fractures--a case series study.

BACKGROUND: Polymethylmethacrylate (PMMA) cement-augmented dynamic hip screws (DHS) have been used as a solution in unstable intertrochanteric fractures (ITF). Our aim was to investigate the complications in PMMA cement-augmented DHS.

METHODS: All patients who had received DHS plate osteosynthesis with or without PMMA cement augmentation from August 2005 to July 2009 in one medical center were retrospectively reviewed. The fractures were classified as unstable (31-A2.2, 31-A2.3 and 31-A3) on the basis of the Arbeitsgemeinschaft für Osteosynthesefragen classification. Inclusion criteria were patients older than 75 years, unstable ITF treated with cement-augmented DHS, and a minimum of 12 months of follow-up. Exclusion criteria were stable ITFs, incomplete chart records and imaging studies, loss to follow-up or death before bone union.

RESULTS: Three hundred twenty-one patients received DHS during the study period. Sixty-seven patients were included in the study (25 men and 42 women; mean age, 81.2 years). The mean follow-up time was 40.2 months, and the mean union time was 18.5 weeks (12-40 weeks). No patient had a lag screw cut-out. Six patients had delayed union or nonunion with side plate failures, including side plate breakage in 1 patient, screw breakage in 3, screw pullout in 1, and recurrent side plate breakage and screw breakage in 1. Deep infection occurred in 1 patient, and 1 had osteonecrosis at the femoral head. The procedure-related complication rate was 8.9%.

CONCLUSIONS: Cement-augmented DHS have a different failure mode than screw cutout in conventional DHS. Failures tended to be more related to delayed union, nonunion and resultant side plate construct failure.