Session V - Geriatrics

Reverse Obliquity Fractures of the Proximal Femur

George J. Haidukewych, MD; T. Andrew Israel, MD; Daniel J. Berry, MD, Mayo Clinic and Mayo Foundation, Rochester, MN

Introduction: The reverse obliquity fracture of the proximal femur is a recognized distinct fracture pattern mechanically different from most intertrochanteric fractures. There are no published reports specifically investigating the treatment of these fractures. The purpose of this paper is to determine the incidence and the results and complications of treating these fractures.

Materials and Methods: Between 1/1/1988 and 12/31/1998, 2,472 consecutive patients with hip fractures were treated at our level one trauma center; 1,035 of these were classified as intertrochanteric or subtrochanteric. Clinical and radiographic material was retrospectively reviewed and 55 fractures were identified with reverse obliquity. Fifty-three patients were treated with ORIF and 2 with primary prosthetic replacement. Three patients died in the first 30 days and 3 were lost to follow up. The remaining 49 were followed until union, revision to a prosthesis or at least one year. The mean clinical follow up was 17.8 months (2-67months) and the mean radiographic follow up was 14 months (2-60 months). Fractures were classified by number and displacement of fragments Results were analyzed by fracture pattern, implant type used, quality of reduction and implant position. Function was assessed by pain, living situation, need for gait aids and ambulatory capacity.

Results: For the group as a whole the rate of failure of fixation or fracture union was 31.9%. The failure rate for the sliding hip screw was 9/16 (56%), for the blade plate 2/15 (13%), for the dynamic condylar screw 3/10, for the cephalomedullary nails 1/3, and for the intramedullary hip screws 0/3. The blade plate proved superior to the sliding hip screw (p=0.023). Twenty-three fractures were anatomically reduced, of these 17% failed. Twenty-four were non-anatomic and of these 46% failed (p=0.060). Of 42 fractures with ideally placed implants, 11 (26%) failed; of 5 non-ideally placed implants 4 (80%) failed (p=0.023). Of the fifteen fractures that failed ORIF five were treated with revision to a calcar replacement prosthesis, 8 with revision ORIF with bone grafting and two refused surgery due to limited functional demands. All fractures that underwent revision ORIF united. At last review 98% of patients had no pain and 2% had moderate pain.

Conclusions: The reverse obliquity fracture makes up 2.2% of all hip fractures and 5.3% of all intertrochanteric and subtrochanteric fractures. The overall failure rate of internal fixation is higher than that for standard intertrochanteric fractures. The blade plate performed significantly better than the sliding hip screw, which had an unacceptable rate of failure. Results were influenced by implant type, quality of reduction and implant position. Failures of fixation without articular surface damage were successfully treated with revision ORIF and bone grafting, while failures with articular surface damage were successfully treated with prosthetic replacement.