Good 10-year results with press-fit cementless cup fixation

No radiolucencies seen at five years postop had progressed and no new radiolucencies had appeared at 10 years follow-up.

Total hip replacement performed using a porous-coated titanium acetabular component implanted with a press-fit technique yields good stability at 10 years postop, a new retrospective study shows.

Garth P. Grobler, MD, and colleagues at the Princess Alice Orthopaedic Unit, Groote Schuur Hospital in Cape Town, South Africa, reviewed 10-year results for 73 hips in 67 patients. In all cases surgeons implanted a Duraloc 300 prosthesis (DePuy), which has a three-pegged, porous-coated titanium acetabular component and a ring-locking mechanism that secures its polyethylene liner, according to the study.

“Our study has shown that a porous, cementless, three-pegged cup inserted with a press-fit technique provides satisfactory results. No cups were revised for loosening and none showed radiological signs of loosening,” the authors said.

“Cementless fixation provides dynamic, biological security, which is continuously renewed over time. It may be expected that the durability of fixation will extend well beyond 10 years, although rates of wear will need careful monitoring. The major challenge facing today’s arthroplasty surgeons remains wear at the bearing surface,” they added.

The study initially included 100 consecutive procedures among 93 patients with mean age of 54 years. Diagnoses included osteoarthritis in 60 hips, avascular necrosis in 10, rheumatoid arthritis in 10, dysplasia in nine, post-traumatic arthritis in three, Gaucher’s disease and arthrodesis in one each, and various diagnoses in six.

Four patients could not be contacted for the 10-year follow-up. Twenty-two patients (23 hips) had died at a mean six years postop, but had not undergone revision. Radiographs taken at a mean 1.3 years before death showed satisfactory fixation in all these cases, the authors said.

Radiographs at 10 years showed no radiolucencies and good acetabular component fixation in 64 of the remaining 73 hips, according to the study.

Initial postoperative radiographs showed radiolucencies present in 27 hips, with nine hips still having evidence of radiolucencies at five years. However, none of these had progressed at 10 years follow-up and no new radiolucencies had appeared, the authors said.

“No lucency seen at 10 years was more than 1 mm wide and no acetabular component showed evidence of migration,” they noted.

Prostheses had a mean linear wear rate of 0.12 mm per year, according to the study. However there was no correlation between wear and abduction, polyethylene thickness, patient age or preoperative diagnosis, the authors said.

No components had been revised for aseptic loosening, although three patients did develop periacetabular osteolysis. These patients underwent revision at another institution, the authors said.

For more information:
Grobler GP, Learmonth ID, Bernstein BP, Dower BJ. Ten-year results of a press-fit, porous-coated acetabular component. J Bone Joint Surg Br. 2005;87-B:786-789.