A Randomized Controlled Trial Comparing Oxinium and Cobalt-Chrome on Standard and Cross-Linked Polyethylene

Background Patients 50 years or younger are at high risk for wear-related complications of their total hip arthroplasty (THA) because of their generally higher levels of activity. Highly crosslinked polyethylene (HXLPE) is believed to be more durable for this population than conventional polyethylene because of its improved wear; however, limited information is available on the wear of HXLPE in this population, particularly the wear of HXLPE when it articulates with alternative bearings like Oxinium (Smith & Nephew, Memphis, TN, USA).Questions/purposes The purpose of this study was to evaluate two questions relative to this population of patients undergoing THA. First, what was the linear and volumetric wear rate of HXLPE in patients 50 years or younger at a minimum followup of 9 years and was osteolysis observed in any of these hips? Given the potential for damage to the Oxinium femoral head surface, was the wear of HXLPE in the patients with this material similar to the other bearings or was there accelerated or runaway wear that was visible in any of the patients? Methods From November 1999 to April 2005, 105 THAs were performed in 95 patients 50 years of age or younger (mean, 42 years; range, 20-50 years). The mean body mass index was 30 kg/m 2 (range, 17-51 kg/m 2 ).The mean followup was 12 years (range, 9-14 years). Two patients died, five patients (one bilateral) were lost to followup, and one hip was revised elsewhere for pain. The patients' information was not included in the study, which left 87 patients with 96 hips for analysis. Highly crosslinked polyethylene was the acetabular bearing for all of the hips. We analyzed the linear and volumetric wear of all of the hips using the Martell method. Eighty hips had the same diameter head (28 mm) allowing us to more accurately compare the different bearing materials. The type of femoral head used was related to our sequential use of materials beginning with cobalt chrome (14), ceramic (23) followed by Oxinium (43) in the hips with 28-mm heads. Although cobalt-chrome was used early in this study, our previous experience with ceramic on polyethylene encouraged us to use it as an alternative bearing. The Oxinium was used consecutively for the remaining hips. Results The mean wear of the HXLPE after 1 year of bedding-in (true linear wear)was 0.022 mm/year (95% confidence interval [CI], 0.015-0.030 mm/year). The mean volumetric wear of HXLPE after 1 year of bedding-in (true volumetric wear) was 9 mm 3 /year (95% CI, 4-14 mm 3

Section: Discussionsupporting

confidence: 82%

Section: Methodsmentioning

confidence: 99%

Low Wear Rates Seen in THAs With Highly Crosslinked Polyethylene at 9 to 14 Years in Patients Younger Than Age 50 Years

Garvin

White

Dusad

et al. 2015

“…Oxidized zirconium femoral heads on XLPE are associated with considerably less wear on hip wear simulators compared with cobaltchrome femoral heads articulating to either CPE or XLPE liners even when damaged [5,17]. Long-term clinical data related to oxidized zirconium on XLPE coupling are lacking with only a few studies showing satisfactory performance in early and midterm stages [13,15,29]. To the best of our knowledge, there are no studies comparing oxidized zirconium head couplings with ceramic head couplings.…”

Section: Discussionmentioning

confidence: 94%

“…In addition, oxidized zirconium femoral heads have been developed; the design rationale of this surface was the combination of ceramic wear characteristics and the mechanical properties of the metallic substrate [1,5,16,17]. In clinical terms, XLPE has been combined with cobalt-chrome, ceramic, and oxidized zirconium femoral heads [12,29,[33][34][35]. However, the in vivo midterm wear performance of the two existing sizes [3,7] of oxidized zirconium femoral heads has not been compared with that of ceramic heads.…”

Section: Discussionmentioning

confidence: 99%

Oxidized Zirconium Head on Crosslinked Polyethylene Liner in Total Hip Arthroplasty: A 7- to 12-year In Vivo Comparative Wear Study

Karidakis

Karachalios

2015

Background Osteolysis resulting from wear debris production from the bearing surfaces is a major factor limiting long-term survival of hip implants. Oxidized zirconium head on crosslinked polyethylene (XLPE) is a modern bearing coupling. However, midterm in vivo wear data of this coupling are not known. Questions/purposes The purpose of this study was to investigate in vivo whether the combination of an oxidized zirconium femoral head on XLPE produces less wear than a ceramic head on XLPE or a ceramic head on conventional polyethylene (CPE) couplings and whether any of these bearing combinations results in higher hip scores. Methods Between 2003 and 2007, we performed 356 total hip arthroplasties in 288 patients; of those, 199 (69.1%) patients (199 hips) were enrolled in what began as a randomized trial. Unfortunately, after the 57 th patient, the randomization process was halted because of patients' preference for the oxidized zirconium bearing instead of the ceramic after (as they were informed by the consent form), and after that, alternate allocation to the study groups was performed. Hips were allocated into four groups: in Group A, a 28-mm ceramic head on CPE was used; in Group B, a 28-mm ceramic head on XLPE; in Group C, a 28-mm Oxinium head on XLPE; and in Group D, a 32-mm Oxinium head on XLPE. The authors prospectively collected in vivo wear data (linear wear, linear wear rate, volumetric wear, and volumetric wear rate) using PolyWare software. Preoperative and postoperative clinical data, including Harris and Oxford hip scores, were also collected at regular intervals. Of those patients enrolled, 188 (95%) were available for final followup at a minimum of 7 years (mean, 9 years; range, 7-12 years). Results All bearing surfaces showed a varying high bedding-in effect (plastic deformation of the liner) up to the second postoperative year. At 5 years both oxidized zirconium on XLPE groups showed lower (p \ 0.01) volumetric wear (mean ± SD mm 3 ) and volumetric wear rates (mean ± SD mm 3 /year) ( Res (2015) 473:3836-3845 DOI 10.1007 Clinical Orthopaedics and Related Research ® A Publication of The Association of Bone and Joint Surgeons® (Group C: 356 ± 64 to 215 ± 54 mm 3 /year, Group D: 354 ± 50 to 210 ± 64 mm 3 /year) when compared with ceramic on CPE (Group A: 895 ± 131 to 380 ± 80 mm 3 /year) and ceramic on XLPE (Group B: 1625 ± 253 to 480 ± 101 mm 3 /year) groups. When wear rates of both oxidized zirconium groups were compared, no differences were found at any time interval with the numbers available. Two hips (one from Group A and one from Group B) are scheduled for revision as a result of wear and osteolysis. There were no differences in hip scores among the groups with the numbers available. Conclusions In this study, in vivo wear parameters were lower when the combination of an oxidized zirconium head on XLPE liner was used at an average of 9 years (range, 7-12 years) followup. Further larger-scale clinical studies should confirm these findings and evaluate osteolysis and revision rates...

“…Oxidized zirconium (Oxinium; Smith & Nephew, Memphis, TN, USA) was introduced in 1997 based on favorable in vitro data [2,8]. We are aware of only three in vivo studies, including two randomized trials, that have assessed its actual clinical benefits in terms of reduced wear when compared with metal in primary THAs [5,12,21]. Also, these studies have been limited by their minimum followup of only 2 years, and none evaluated Charnley-type low-friction torque arthroplasty, which we define as a 22.25-mm femoral head articulating with an all-cemented polyethylene socket.…”

Section: Introductionmentioning

confidence: 99%

Do Oxidized Zirconium Femoral Heads Reduce Polyethylene Wear in Cemented THAs? A Blinded Randomized Clinical Trial

Zaoui

Hage

Langlois

et al. 2015

Background Charnley low-friction torque total hip arthroplasty (THA) remains the gold standard in THA. The main cause for failure is wear of the socket. Highly crosslinked polyethylene (HXLPE) has been associated with reduced wear rates. Also, oxidized zirconium has shown in vitro reduced wear rates. However, to our knowledge, there are no data comparing oxidized zirconium femoral heads with metal heads against HXLPE or ultrahigh-molecular-weight polyethylene (UHMWPE) when 22.25-mm bearings were used, which was the same size that performed so well in Charnley-type THAs. Questions/purposes We hypothesized that after a minimal 4-year followup (1) use of HXLPE would result in lower radiographic wear than UHMWPE when articulating with a stainless steel head or with an oxidized zirconium head; (2) use of oxidized zirconium would result in lower radiographic wear than stainless steel when articulating with UHMWPE and HXLPE; and (3) there would be no difference in terms of Merle d'Aubigné scores between the bearing couple combinations. Methods One hundred patients were randomized to receive cemented THA with either oxidized zirconium or a stainless steel femoral head. UHMWPE was used in the first 50 patients, whereas HXLPE was used in the next 50 patients. There were 25 patients in each of the four bearing couple combinations. All other parameters were identical in both groups. Complete followup was available in 86 of these patients. Femoral head penetration was measured using a validated computer-assisted method dedicated to all-polyethylene sockets. Clinical results were compared between the groups using the Merle d'Aubigné score. Results In the UHMWPE series, the median steady-state penetration rate from 1 year onward was 0.03 mm/year (range, 0.003-0.25 mm/year) in the oxidized zirconium group versus 0.11 mm/year (range, 0.03-0.29 mm/year) in the metal group (difference of medians 0.08, p\0.001). In the HXLPE series, the median steady-state penetration rate from 1 year onward was 0.02 mm/year (range, À0.32 to 0.07 mm/year) in the oxidized zirconium group versus 0.05 mm/year (range, À0.39 to 0.11 mm/year) in the metal group (difference of medians 0.03, p \ 0.001). The Merle d'Aubigné scores were no different between the groups with a median of 18 in each of the groups (range, 16-18). Conclusions This study demonstrated femoral head penetration was reduced by oxidized zirconium when compared with metal on both UHMWPE and HXLPE. However, apart the metal-UHMWE group, all other groups had a steady-state penetration rate well below the osteolysis threshold with a low difference between groups that