Cementless total hip arthroplasty in patients with severely dysplastic hips and a previous Schanz osteotomy of the femur: techniques, pitfalls, and long-term outcome

Abstract

Background and purpose: Historically, a Schanz osteotomy of the femur has been used to reduce limp in patients with severely dysplastic hips. In such hips, total hip arthroplasty is a technically demanding operation. We report the long-term results of cementless total hip arthroplasty in a group of patients who had all undergone a Schanz osteotomy earlier.

Patients and methods: From 1988 through 1995, 68 total hip replacements were performed in 59 consecutive patients previously treated with a Schanz osteotomy. With the cup placed at the level of the true acetabulum, a shortening osteotomy of the proximal part of the femur and distal advancement of the greater trochanter were performed in 56 hips. At a mean of 13 (9-18) years postoperatively, we evaluated these patients clinically and radiographically.

Results: The mean Harris hip score had increased from 51 points preoperatively to 93 points. Trendelenburg sign was negative and there was good or slightly reduced abduction strength in 23 of 25 hips that had not been revised. There were 12 perioperative complications. Only 1 cementless press-fit porous-coated cup was revised for aseptic loosening. However, the 12-year survival rate of these cups was only 64%, as 18 cups underwent revision for excessive wear of the polyethylene liner and/or osteolysis. 6 CDH femoral components had to be revised due to technical errors.

Interpretation: Our results suggest that cementless total hip arthroplasty combined with a shortening osteotomy of the femur and distal advancement of the greater trochanter can be recommended for most patients with a previous Schanz osteotomy of the femur. Because of the high incidence of liner wear and osteolysis of modular cementless cups in this series, nowadays we use hard-on-hard articulations in these patients.

Figure 1.

A 54-year-old woman who had high congenital dislocation of both hips. At the age of 17, she had undergone a bilateral high-seated Schanz osteotomy to reduce limp. A. Preoperatively. B. 9 years after a cementless total hip arthroplasty of the left hip and 8 years after a similar procedure on the left hip. Both hips underwent femoral shortening and advancement of the greater trochanter. The leg-length discrepancy was 1 cm (the left side being shorter). There were no radiographic signs of loosening of the components and no signs of polyethylene wear.

Figure 2.

Osteotomies used for various deformities of the femur. The femoral shaft is usually transected distal to the lesser trochanter, as shown by the transverse solid line in (A). A dotted line demonstrates the most distal possible level of the osteotomy. A. Proximal shortening osteotomy with distal advancement of the greater trochanter (vertical solid line) in hips with a previous proximal Schanz osteotomy. B. Segmental shortening with angular correction for hips with a previous, more distal Schanz osteotomy. Copyright for the illustrations in this figure is owned by The Journal of Bone and Joint Surgery, Inc. (published in Eskelinen et al. Cementless total hip arthroplasty in patients with high congenital hip dislocation, J Bone Joint Surg Am. 2006; 88: 80-91). Reproduced with permission.

Figure 3.

Kaplan-Meier survival curve for the press-fit porous-coated Figure 4. Kaplan-Meier survival curve for the CDH femoral compo-acetabular components, with cup revision because of aseptic loosennents, with stem revision for any reason as the endpoint. CI: confi-ing and cup revision for any reason as the endpoints. CI: confidence dence interval. interval.

Figure 4.

Kaplan-Meier survival curve for the CDH femoral components, with stem revision for any reason as the endpoint. CI: confi-dence interval.