Outcomes of osteoporotic trochanteric fractures treated with cement-augmented dynamic hip screw

Dynamic hip screw (DHS) has been the standard treatment for stable trochanteric fracture patterns, but complications of lag screw cut out from a superior aspect, due to inadequate bone anchorage, occur frequently in elderly osteoporotic patients. Polymethylmethacrylate (PMMA) has been used as an augmentation tool to facilitate fixation stability in cadaveric femora for biomechanical studies and in pathological fractures. However, there are very few reports on the utilization of PMMA cement to prevent these complications in fresh intertrochanteric fractures. A prospective study was conducted to evaluate the outcome and efficacy of PMMA augmented DHS in elderly osteoporotic patients with intertrochanteric fractures.

The study included 64 patients (AO type31-A2.1 in eight, A2.2 in 29, A2.3 in 17 patients, and 31-A3.1 in five, A3.2 in three, and A3.3 in two patients) with an average age of 72 years (60 - 94 years) of which 60 were available for final followup. PMMA augmentation of DHS was performed in all cases by injecting PMMA cement into the femoral head with a custommade gun designed by the authors. The clinical outcome was rated as per the Salvati and Wilson scoring system at the time of final followup of one year. Results were graded as excellent (score > 31), good (score 24 - 31), fair (score 16 - 23), and poor (score < 16).

Fracture united in all patients and the average time to union was 13.8 weeks (range 12 - 16 weeks). At an average followup of 18 months (range 12 - 24 months), no incidence of varus collapse or superior screw cut out was observed in any of the patients in spite of weightbearing ambulation from the early postoperative period. There was no incidence of avascular necrosis (AVN) or cement penetration into the joint in our series. Most of the patients were able to regain their prefracture mobility status with a mean hip pain score of 8.6.

Cement augmentation of DHS appears to be an effective method of preventing osteoporosis related complications of fracture fixation in the trochanteric fractures. The technique used for cement augmentation in the present study is less likely to cause possible complications of cement augmentation like thermal necrosis, cement penetration into the joint, and AVN hip.