Outcome of revision in comparison with primary total knee arthroplasty in Iran

In the recent decade, many primary total knee arthroplasties have been carried out in Iran and the number of revision cases is expected to rise with the aging population. The aim of this study was to report the outcome of revision surgery in the country and make a comparison between the outcome of revision and that of the primary arthroplasty. Retrospectively, each case of 19 consecutive revision total knee arthroplasties was matched individually with two cases of primary total knee arthroplasty based on gender and age (within 5 years) in order to compare the outcome in the two groups of revision and primary arthroplasties. Detailed demographic data, underlying diagnosis, patient-reported pain severity, and Knee Society score were recorded pre-operatively and in the third month after the surgery for each patient in the two groups. Using chi-square, fisher''s exact, one-way ANOVA, independent, and paired t-tests, we compared the outcomes in two groups as well as in each group before and after the arthroplasty. Knee pain was significantly decreased after the surgery in the two groups of revision (p = 0.031) and the primary (p < 0.001) arthroplasty. There was no statistically notable difference of post-operative pain between the two groups of revision and primary TKA. The Knee Society score remarkably increased in both groups after the surgery (both ps < 0.001). The differences of Knee Society scores before and after the surgery were calculated separately in each group and compared to show that the primary group had a better outcome (p < 0.001) rather than the revision arthroplasty group. Satisfactory outcomes were obtained in our revision total knee arthroplasties; however, the primary arthroplasties had better results. The results of surgery appear to be closely related to the technical demands placed on surgeon. Because we have to deal with more cases of revision total knee arthroplasty in near future, more comprehensive risk factor assessment studies with large sample size are required for gaining better results.