Femoral shortening after surgical treatment of trochanteric fractures in nongeriatric patients

Background: Femoral shortening is a well-known clinical finding after surgical treatment of per- and intertrochanteric fractures. Particularly, in geriatric patients with poor bone quality and unstable fracture types, secondary compression of these fractures often leads to length inequality of the lower limbs. In younger patients with good bone quality and mobilization with delayed weight bearing, limb length shortening is expected to be a rare complication. The purpose of this study was to analyze incidence and degree of femoral shortening in patients younger than 60 years of age after fixation of different types of per- and intertrochanteric fractures. In addition, we compared the results of two different implants, which were used for operative treatment. Methods: Ninety-five patients, younger than 60 years of age, were evaluated for femoral shortening after surgical treatment of per- and intertrochanteric fractures between 1997 and 2002. Follow-up examinations took place at an average of 3.2 years (2-5 years) after trauma. Fractures were classified by the AO/OTA system and divided into sub-types 31 A1, 31 A2, and 31 A3. Two different implants (dynamic hip screw and cephalomedullary nail) were used for operative treatment, mainly depending on type and stability of the fracture. Femoral shortening was analyzed by standardized lower extremity radiographs measuring the distance from the top of the femoral head to the center of a line drawn between the most distal part of the medial and lateral femoral condyles. Results: Fifty-seven patients were treated by a cephalomedullary nail, 38 by dynamic hip screw. Femoral shortening was seen in 46 patients (48%) with a mean value of 11 mm. Twenty-two patients had a femoral inequality of less than 10 rum, 17 patients an inequality between 10 mm and 20 rum, and 7 patients a shortening of more than 20 mm. Statistical analysis revealed that fracture type and implant had a significant influence on the shortening: In patients with fracture types 31 A2 and A3 femoral shortening was found to be more severe than in patients with fracture type 31 A1. Additionally, in unstable fracture types (31 A2 and A3) femoral shortening was significantly larger, if patients were treated by dynamic hip screw than by a cephalomedullary nail. Conclusion: Femoral shortening after operative treatment of per- and intertrochanteric fractures was found to be a common clinical finding in nongeriatric patients. Nearly half of them showed a lower limb length inequality after fracture fixation. The degree of the shortening was rather low and depended mainly on the fracture type. Comparing the two different implants used for operative treatment, a cephalomedullary nail was more successful in preventing limb length discrepancy in unstable fracture types than dynamic hip screw.