Quality of life and functional outcome after single-radius and multi-radius total knee arthroplasty.

PURPOSE: The main objective of this study was to compare quality of life and functional outcome in patients who have undergone a single-radius (SR) or multi-radius (MR) total knee arthroplasty (TKA). The secondary objective was to observe changes in knee range of movement (ROM) and standardized knee scores (KSCs) in these patients. The hypothesis was that there would be no statistically significant difference between the two patient groups in quality of life and functional outcome.

METHODS: One hundred three SR TKAs were performed by a single surgeon between August 2008 and December 2012. A propensity score matching algorithm was used to select 103 MR TKAs performed during the same period. Preoperative and postoperative variables such as standardized knee and quality of life scores were captured prospectively and then analyzed via both the Student's t-test and paired t-test to look for statistically significant differences between the SR and MR patient groups.

RESULTS: At 2 years postoperatively, there was no statistically significant difference between the SR and MR patient populations in knee extension, Oxford Knee Score, Knee Society Clinical Rating Scores, and the Physical Component Summary of the Short Form 36 Health Survey (SF-36). There was a statistically significant difference between the two patient groups in postoperative knee flexion in favor of the MR design ( p = 0.011).

CONCLUSION: While an SR femoral implant design has several theoretical biomechanical advantages, postoperative standardized KSCs and quality of life scores in this single-surgeon series do not show a clear advantage of one design over the other.

LEVEL OF EVIDENCE: III.