Oxidized zirconium versus cobalt-chrome femoral heads in total hip arthroplasty: a multicentre prospective randomized controlled trial with ten years’ follow-up

Abstract

Aims This study reports the ten-year wear rates, incidence of osteolysis, clinical outcomes, and complications of a multicentre randomized controlled trial comparing oxidized zirconium (OxZr) versus cobalt-chrome (CoCr) femoral heads with ultra-high molecular weight polyethylene (UHMWPE) and highly cross-linked polyethylene (XLPE) liners in total hip arthroplasty (THA). Methods Patients undergoing primary THA were recruited from four institutions and prospectively allocated to the following treatment groups: Group A, CoCr femoral head with XLPE liner; Group B, OxZr femoral head with XLPE liner; and Group C, OxZr femoral head with UHMWPE liner. All study patients and assessors recording outcomes were blinded to the treatment groups. The outcomes of 262 study patients were analyzed at ten years’ follow-up. Results Patients in Group C were associated with increased mean liner wear rates compared to patients in Group A (0.133 mm/yr (SD 0.21) vs 0.031 mm/yr (SD 0.07), respectively; p < 0.001) and Group B (0.133 mm/yr (SD 0.21) vs 0.022 mm/yr (SD 0.05), respectively; p < 0.001) at ten years’ follow-up. Patients in Group C were also associated with increased risk of osteolysis and aseptic loosening requiring revision surgery, compared with patients in Group A (7/133 vs 0/133, respectively; p = 0.007) and Group B (7/133 vs 0/135, respectively; p = 0.007). There was a non-statistically significant trend towards increased mean liner wear rates in Group A compared with Group B (0.031 mm/yr (SD 0.07) vs 0.022 mm/yr (SD 0.05), respectively; p = 0.128). All three groups were statistically comparable preoperatively and at ten years’ follow-up when measuring normalized Western Ontario and McMaster Universities Osteoarthritis Index (p = 0.410), 36-Item Short Form Health Survey (p = 0.465 mental, p = 0.713 physical), and pain scale scores (p = 0.451). Conclusion The use of UHMWPE was associated with progressively increased annual liner wear rates after THA compared to XLPE. At ten years’ follow-up, the group receiving UHMWPE demonstrated an increased incidence of osteolysis and aseptic loosening requiring revision surgery compared to XLPE. Femoral heads composed of OxZr were associated with trend towards reduced wear rates compared to CoCr, but this did not reach statistical significance and did not translate to any differences in osteolysis, functional outcomes, or revision surgery between the two femoral head components. Cite this article: Bone Joint J 2022;104-B(7):833–843.

Comparison between ceramic-on-polyethylene versus metal-on-polyethylene prostheses in Total Hip Arthroplasties: a systematic review and meta-analysis

“…In addition, long-term survival is higher in femoral heads of 32 mm, especially when associated with the tribological pair of metal XLPE. In linear wear data in subgroups of femoral stem heads with different measures (22,26,28, and 32 mm) in hip arthroplasty, there is no evidence of difference between ceramic XLPE and metal XLPE.…”

“…The literature suggests that osteolysis is infrequent when the wear rate is less than 0.1 mm/year and almost absent when the wear rate is less than 0.05 mm/year 29 . Jassim et al 18 found that the linear wear difference was 0.005 mm/year, while Kaiany et al 28 found it to be 0.009 mm/year, favorable to ceramic XLPE components.…”

“…Kayani et al 28 This was a multicenter study including 401 patients aged over 18 years with degenerative/erosive disease due to hip OA, avascular necrosis, or rheumatoid arthritis undergoing THA. Prostheses with a 32-mm head, composed of metal-on-polyethylene versus ceramic-on-polyethylene, were compared.…”

“…Bjorgul, et al16 Ise, et al17 Jassim, et al18 Jonsson, et al19 Kadar, et al20 Kawate, et al21 Kim22 Kraay, et al23 Morison, et al24 Nakahara, et al25 Zaoui, et al26 Bergvinsson, et al27 Kayani, et al28 ITT: Intention to treat.Absence of biasPresence of bias Absence of information Rev Assoc Med Bras…”