Stable and unstable pertrochanteric femoral fractures. Differentiated indications for the dynamic hip screw

The aim of all surgical procedures in the treatment of trochanteric fractures in elderly and even geriatric patients is achievement of initial stability. We examined in a clinical trial whether primary stability was achieved in all types of trochanteric fractures following osteosynthesis with the Dynamic Hip Screw (DHS). From 1994 to 1996, 122 patients with trochanteric fractures had osteosynthesis by dynamic hip screw. Patient records were evaluated and all data got registered with a standardized protocol;clinical radiological outcome was analysed after an average period of 1.9 years after injury according to the Traumatic Hip Rating Score. 22% of all patients died meantimes, 51.6% of the remaining 95 patients could get examined. The average age was 75.5 years, the patient population showed an increased preoperative morbidity (2.5 points) according to ASA-Score. 81% showed progressive osteoporosis. According to the AO-classification 47% stable fractures (type A-1) and 53% instable trochanteric fractures (type A-2 and A-3) occurred. Surgery lasted 77 minutes average in osteosynthesis of stable fractures. The duration of 108 minutes in instable fractures was significantly higher, as well as the blood loss was 43% increased in these complex fractures. Complications closely associated to the osteosynthesis appeared only in instable fractures (7%). Also common complications (24.6%) predominated with 15.6% in type A-2 and A-3 fractures versus 9% in type A-1 fractures; mortality was also different with 5.7% versus 1.6%. Assessment of the functional outcome according to THRS showed a significant deterioration of 20 points in 71% of all patients compared with the preoperative score. The results show that dynamic hip screw osteosynthesis in instable trochanteric fractures is associated to a higher incidence of complications. While the dynamic hip screw still represents the standard implant in stable fractures of the trochanteric region, being aware of improved intramedullary implants regarding biomechanical features and surgical technique, the results justify to critical consider the use of DHS for osteosynthesis in instable fractures of the trochanteric region.