Review article: Polyethylene wear and osteolysis in total hip arthroplasty

Journal of Orthopaedic Surgery, Jun 2001 by Zhu, Y H, Chiu, K Y, Tang, W M

The major indications for surgical intervention include pain and radiographic evidence of progressive bone resorption that compromises future reconstruction. However, surgical intervention may also be necessary in some patients who have definite evidence of polyethylene wear and osteolysis without any symptoms18. Such active intervention seems to be of great value since polyethylene wear alone is an impending failure and thus may lead to revision when symptoms develop. Therefore, the natural history of osteolytic lesions and relevant follow-up will be important in deciding the suitable time for surgery.".

For many of the special problems outlined, there are no current management guidelines. Intraoperative assessment may be the only means to determine what is appropriate for the particular situation. If the femoral stem is still stable though osteolysis can be found, debridement of granulation tissues and articulation changing may help in addition to postoperative observation (Fig. 2). Surgical debridement is the key method of stabilizing defects regardless of the ultimate fixation mode since it removes the enzymatic and particulate debris responsible for osteolysis17. If the femoral component is loose and bone loss is not too severe, it may be replaced with a long stem cemented prosthesis. The recurrence of lysis still remains low if a femoral component is cemented into a hip that has developed osteolysis before revision.27 Alternatively, cementless prosthesis can also be used (Fig. 4d). When a severe bone defect appears, structure bone grafting may be needed before implanting a new prosthesis. As for pelvic osteolysis, if a metal-backed acetabular component is solidly fixed, it is not necessary to remove it and revision may require exchange of a modular polyethylene liner and a femoral head of suitable size (Fig. 3). The periarticular inflammatory tissue in osteolytic lesions should be completely debrided and allograft bone chips are packed into the defect if necessary (Fig. 4).23,28 To deal with a large bone defect in the acetabulum, structural grafting is usually necessary. Total revision of the acetabular component is needed only when the shell is unstable. An anti-- protrusio ring is indicated for severe acetabular bone loss when a cementless hemispherical cup has little stability or poor contact with the host bone. The bony defect will be packed with a morselized allograft. An acetabular cup is then cemented into the ring.

When polyethylene wear and osteolysis occurs, it seems that a surgeon has no other choice in the end except revision total hip arthroplasty. As described at the beginning, polyethylene wear and osteolysis still remain a serious potential problem for all patients who have had a total hip arthroplasty. Despite a large amount of work having been done, there are still many questions to be answered and many problems to be solved. Whether such a difficult problem can be dealt with will determine the development and the future of joint replacement surgery.