Calcar resorption after total hip arthroplasty.

Calcar resorption is a significant complication after total hip arthroplasty and may result in technical problems at revision of failed hip arthroplasties. Radiographs and patient data from a series of 129 consecutive primary total hip arthroplasties were evaluated 5 years after surgery to study factors associated with calcar resorption. The incidence of calcar resorption was 21%. Primary positive calcar-collar contact reduced the incidence of calcar resorption. Sufficient cementation of the medullary canal significantly reduced the incidence of calcar resorption, as did neutral and valgus positioning of the femoral component. Loosening of the acetabular component occurred more often in the group with calcar resorption. Middle-aged patients and men were more prone to develop resorption of the calcar. Calcar resorption may be influenced by surgical technique. Alteration of the operative technique is recommended, with emphasis on correct valgus or neutral position of the femoral component, a positive calcar-collar contact, and improved cementation.