Two-stage treatment of acetabular bone defect in tuberculosis of the hip by intended ankylosis followed by total hip arthroplasty: a case report

INTRODUCTION In case of severe post-tuberculosis osteoarthritis of the hip, arthrodesis, excision arthroplasty, or total hip arthroplasty may be considered. The latter can be challenging, because destruction of the joint, and most importantly the acetabulum, is frequently seen. To fill up acetabular bone stock loss during total hip arthroplasty, there is the possibility to use bone auto-grafts and allografts. Complications are graft rejection, mechanical failure of implants and gradual migration of the cup into the graft. Other options for creating a stable acetabular component in total hip replacement are screw fixation of the acetabular component or using a stemmed acetabular component. An alternative is the use of an anti-protrusion cage, for which the risk of loosening however is known. In young patients especially, such solution are not always appealing. Therefore, we created an intended ankylosis of the hip joint to fill up the acetabular bone loss with the patients own femoral head. To our knowledge this treatment strategy has not been described before. CASE PRESENTATION We present a 33-year-old Caucasian woman with an acetabular bone defect caused by tuberculous arthritis of the left hip joint. Instead of performing a resection arthroplasty followed by total hip arthroplasty in a second stage, we decided to intentionally ankylose the hip joint in order to fill up the acetabular defect with the patient's own femoral head. Two years after the start of a one year course of tuberculostatic chemotherapy, we took down the ankylosed hip and placed an uncemented total hip prosthesis. The technical and functional outcome of this procedure appeared to be very favourable, the acetabular defect was filled up and the bone remodeled completely. CONCLUSION In order to resolve the problem of acetabular osseous defects in tuberculous arthritis of the hip, intended spontaneous fusion of the femoral head with the acetabular can be a favorable treatment strategy. Subsequently this situation was used as a solid base for the acetabular component of the total hip prosthesis. It resulted in a optimal acetabular bone stock during acetabular component implantation with a very good technical and clinical outcome at 40-months follow up It is understood that this method may not be applicable to all resembling patients. However, this solution may be considered worthwhile in individual cases.