Purpose: There has only been one reported series of 30 cases of greater trochanter fracture during total hip arthroplasty and 26 of these were postoperative discoveries. We evaluated the frequency of this event and its postoperative consequences.
Material and methods: Among our series of 1171 total hip arthroplasties performed between 1985 and 2000, 38 patients (3.2%) with greater trochanter fracture were identified (mean age 63 years). Osteosynthesis was performed in all cases. Thirty-one fractures were observed during primary arthroplasty and seven during revision procedures.
Results: Eighteen patients had a favouring condition: corti-costeroid therapy,alcoholism,osteoporosis,diabetes,Paget, ablation of trochanteric material, periprosthetic osteolysis. The anterolateral approach was used in 22 and the posterolateral approach in 16. The fracture occurred along the access route in four (material removal or prefracture situtation), at removal of a previously implanted stem in two, and during implantation in 32. Twelve different stems were involved but a screwed stem was involved in 18 cases, i.e. 10% of all implanted screwed stems, while this complication only occurred in 1.2% of other implanted stems. Immediate weight bearing was authorised in 27 patients and deferred three weeks to three months in eleven. There were two deaths, so follow-up data was available for 36 hips: we observed anatomic bone healing in 22, deformed calluses in five and nonunion in nine, including two cases with infection (three revision procedures were required). Pain persisted at two months for eleven hips and limping persisted for ten (eight nonunions).
Discussion: Prostheses with a large metaphyseal component were involved in the majority of the fractures. The surgical approach was not incriminated. When well stabilised, trochanter fractures healed well. Nonunion, often announced by persistent pain, is an important risk in patients with osteoporosis and a poorly stabilised fracture. Although all cases of nonunion were observed in patients with deferred weight bearing, this criterion is simply the expression of the surgeon’s apprehension in case of less than satisfactory fixation.
Conclusion: Because of the deficient bone stock, which explains the higher rate of nonunion, fracture of the greater trochanter cannot be considered in the same light as a planned osteotomy. Prevention requires choosing a less cumbersome metaphyseal component in patients with favouring conditions. Osteosynthesis must be performed with particular care in order to obtain rapid healing and good functional outcome.
