Radiological and functional outcome in unstable, osteoporotic trochanteric fractures stabilized with dynamic helical hip system

A dynamic hip screw (DHS) remains the implant of choice for stabilization of trochanteric fractures because of its favourable results and low rate of non-union or hardware failure, but complication rates of the DHS are higher in unstable and osteoporotic trochanteric fractures. The proponents of the dynamic helical hip system (DHHS) report that it has the potential to decrease the cut-out rates in such fractures as helical blade allows compaction in osteoporotic femoral head which in itself improves anchorage. The purpose of the present study was to evaluate the radiological and functional outcome of DHHS in unstable and osteoporotic trochanteric fractures. This was a prospective observational study. The mean age of the 51 patients (24 men and 27 women) was 72.8 years. Fractures were type AO31A2.2 in 28 patients and AO31A2.3 in 23 patients. According to DEXA scans, 41 patients had osteoporosis and 10 patients had osteopenia. Osteoporosis was grade 3 in 36 patients and grade 2 in 15 patients according to Singh's index. The mean follow-up was 1.84 years. The average sliding of the lag screw was 3.6 mm (range 2-10 mm). The mean operative time was 54.74 (range 48-65) min. The average tip-apex distance was 20.24 mm (range 12-28 mm). All but one fractures united. The average time to union was 13.14 (range 11-24) weeks. There were four mechanical complications namely late helical blade migration (n = 1), late medialization of shaft (n = 2) and varus collapse with cut through (n = 1). No patient was noted to have a plate pull-out. The average Harris hip score was 92.87 (range 76-97). The use of a DHHS for stabilization of unstable(AO31A2), osteoporotic trochanteric fractures in the elderly patients was associated with reliable rates of union and functional outcome and a decreased incidence of screw cut-out and side plate pull-out.