2019 ISAKOS Biennial Congress ePoster #971
An Optimum Prosthesis Combination of Low Risk TKR Options in All Five Primary Categories of Design Results in a 60% Reduction in Revision Risk
Christopher J. Vertullo, MBBS, PhD, FRACS(Orth), Gold Coast, QLD AUSTRALIA
Stephen E. Graves, MBBS, DPhil, FRACS, FAOrthA, Adelaide, SA AUSTRALIA
Yi Peng, MMed(Epi&Stats), Adelaide, SA AUSTRALIA
Peter L. Lewis, MBBS, FRACS(Orth), FAOrthA, Adelaide, SA AUSTRALIA
Australian Orthopaedic Association National Joint Replacement Registry, Adelaide, SA, AUSTRALIA
FDA Status Cleared
Summary
The lowest risk TKR design combination or Optimum Prosthesis Combination was a fixed bearing, minimally stabilized, hybrid or cemented TKR, using XLPE, with patella resurfacing. Patients who received an Alternative Prosthesis Combination, with one or more options that were not low-risk, had a 151% increased risk of revision at greater than 3 years for all causes and a 148% higher risk of revision
Abstract
Purpose
Decades of innovations in total knee replacement (TKR) design have led to large number of possible prosthesis combinations in regards fixation, posterior stability, bearing mobility, bearing surface, and patella resurfacing, each of which can alter the revision risk. The accumulative effect when the lowest risk combination in each design category, or “Optimum Prosthesis Combination” (OPC) is utilized remains unknown. The purpose of this analysis was to firstly, identify the OPC and to secondly, compare the revision risk of a cohort who received the OPC to a cohort who received an Alternative Prosthesis Combination (APC).
Methods
National registry revision risk data for primary TKR for osteoarthritis were obtained from September 1999 to December 2015 for two patient cohorts, those receiving an OPC and those receiving an APC. OPC was defined as TKR with the lowest revision risk option for five primary TKR design categories; fixation, posterior stability, bearing mobility, bearing surface, and patella resurfacing, while APC had one or more higher-risk options.
Results
Of the 482,373 included TKR, 42,008 (8.7%) were in the OPC cohort, who received a minimally stabilized, fixed bearing TKR with cross-linked polyethylene with patella resurfacing. Both cohorts had similar demographics. At 10-years, the OPC cohort had a Cumulative Percent Revision of 2.4% (95% CI 2.1, 2.8) compared to 5.5% (95% CI 5.4, 5.6) for the APC cohort. For all patients, revision risk of the APC cohort was higher at all times (151% greater at =3 years (p<0.001)). Loosening/lysis was the most common cause of revision in the APC cohort (1.1%), while it was the second-most common cause in the OPC cohort (0.3%). The increased risk was apparent in all age and gender subgroups, with the highest risk increase seen in males =65 years.
Conclusions
Patients receiving the lowest risk prosthesis design combination or Optimum Prosthesis Combination TKR had a 60% lower revision risk, with similar demographics to the Alternative Prosthesis Combination TKR