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  • Alternative bearings in total knee arthroplasty: risk of early revision compared to traditional bearings: an analysis of 62,177 primary cases.

Alternative bearings in total knee arthroplasty: risk of early revision compared to traditional bearings: an analysis of 62,177 primary cases.

Acta orthopaedica (2013-03-15)
Maria C S Inacio, Guy Cafri, Elizabeth W Paxton, Steven M Kurtz, Robert S Namba
ABSTRACT

There is no substantial clinical evidence for the superiority of alternative bearings in total knee arthroplasty (TKA). We compared the short-term revision risk in alternative surface bearing knees (oxidized zirconium (OZ) femoral implants or highly crosslinked polyethylene (HXLPE) inserts) with that for traditional bearings (cobalt-chromium (CoCR) on conventional polyethelene (CPE)). The risk of revision with commercially available HXLPE inserts was also evaluated. All 62,177 primary TKA cases registered in a Total Joint Replacement Registry between April 2001 and December 2010 were retrospectively analyzed. The endpoints for the analysis were all-cause revisions, septic revisions, or aseptic revisions. Bearing surfaces were categorized as OZ-CPE, CoCr-HXLPE, or CoCr-CPE. HXLPE inserts were stratified according to brand name. Confounding was addressed using propensity score weights. Marginal Cox-regression models adjusting for surgeon clustering were used. The proportion of females was 62%. Average age was 68 (SD 9.3) years, and median follow-up time was 2.8 (IQR 1.2-4.9) years. After adjustments, the risks of all-cause, aseptic, and septic revision with CoCr-HXLPE and OZ-CPE bearings were not statistically significantly higher than with traditional CoCr-CPE bearings. No specific brand of HXLPE insert was associated with a higher risk of all-cause, aseptic, or septic revision compared to CoCr-CPE. At least in the short term, none of the alternative knee bearings evaluated (CoCr-HXLPE or OZ-CPE) had a greater risk of all-cause, aseptic, and septic revision than traditional CoCr-CPE bearings.

MATERIALS
Product Number
Brand
Product Description

Supelco
Polyethylene, analytical standard, for GPC, 2,000
Sigma-Aldrich
Polyethylene, Ultra-high molecular weight, average Mw 3,000,000-6,000,000
Sigma-Aldrich
Polyethylene, High density, melt index 12 g/10 min (190 °C/2.16kg)
Sigma-Aldrich
Polyethylene, Linear low density, melt index 1.0 g/10 min (190°C/2.16kg)
Sigma-Aldrich
Polyethylene, low density, melt index 25 g/10 min (190°C/2.16kg)
Sigma-Aldrich
Polyethylene, Ultra-high molecular weight, surface-modified, powder, 125 μm avg. part. size
Sigma-Aldrich
Polyethylene, Medium density
Sigma-Aldrich
Polyethylene, High density, melt index 2.2 g/10 min (190 °C/2.16kg)
Sigma-Aldrich
Polyethylene, Ultra-high molecular weight, surface-modified, powder, 34-50 μm particle size
Sigma-Aldrich
Polyethylene, average Mw ~4,000 by GPC, average Mn ~1,700 by GPC
Polyethylene (LDPE), ERM®, certified reference material