Osteosynthesis of ununited femoral neck fracture by internal fixation combined with iliac crest bone chips and muscle pedicle bone grafting

Abstract

BACKGROUND Ununited femoral neck fracture is seen commonly in developing countries due to delayed presentation or failure of primary internal fixation. Such fractures, commonly present with partial or total absorption of femoral neck, osteonecrosis of femoral head in 8-30% cases with upward migration of trochanter posing problem for osteosynthesis, especially in younger individuals. Several techniques for treatment of such conditions are described like osteotomies or nonvascularied cortical or cancellous bone grafting provided varying degrees of success in terms of fracture union but unsatisfactory long term results occurred due to varying incidence of avascular necrosis (AVN) of femoral head. Moreover, in presence of AVN of femoral head neither free fibular graft nor cancellous bone graft is satisfactory. The vascularied bone grafting by deep circumflex iliac artery based on iliac crest bone grafting, free vascularied fibular grafting and muscle pedicle periosteal grafting showed high incidence of success rate. Osteosynthesis is the preferred treatment of choice in ununited femoral neck fracture in younger individuals. MATERIALS AND METHODS Of the 293 patients operated during the period from June 1977 to June 2009, 42 were lost to followup. Seven patients with gluteus medius muscle pedicle bone grafting (MPBG) were excluded. Thus, out of 244 patients, 208 (85.3%) untreated nonunion and 36 (14.7%) following failure of primary internal fixation were available for studies. Time interval between the date of injury and operation in untreated nonunion cases was mean 6.5 months and in failed internal fixation cases was mean 11.2 months. Ages of the patients varied from 16 to 55 years. Seventy patients had partial and 174 had subtotal absorption of the femoral neck. Evidence of avascular necrosis (AVN) femoral head was found histologically in 135 (54.3%) and radiologically in 48 (19.7%) patients. The patients were operated by open reduction of fracture, cannulated hip screw fixation, iliac crest bone chips and quadratus femoris MPBG. RESULTS The mean followup is 12.5 years (range 3-35). The union of fractures occurred in 202 (82.8%), delayed union in 18 (7.3%), and established nonunion in 24 (9.8%) patients. Full weight bearing was permitted at 16-22 weeks after union of fractures. Mean Harris hip score at the longest followup was 85.5. Among the complications, superficial wound infection occurred in 20 (8.2%), deep infection in seven (2.9%), and coxa vara in 39 (16%) patients. Preoperative radiodensity of femoral head disappeared mostly after the union of fracture whereas fresh radiodensity of femoral head appeared in 20 (8%) patients; nine (45%) of them developed segmental collapse. CONCLUSION Ununited femoral neck fractureis characterized by absorption of femoral neck, posterior cortical defect, smoothening and overriding of fracture surfaces with intervening fibrous tissues associated with or without AVN of femoral head. The above method of osteosynthesis rectified the above pathology and provided satisfactory results with union of fractures in 90.1% patients at long term followup.

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