Postoperative clinical outcome between lateral retraction and eversion of patella following simultaneous bilateral total knee arthroplasty

Abstract Aims and objective Among the various exposure technique used in total knee arthroplasty (TKA); the midline medial parapatellar knee approach is most commonly performed; which require mobilisation of patella for adequate surgical exposure. In this study, we compare the effect of patellar eversion with lateral retraction in simultaneous bilateral TKA to find out difference in postoperative clinical outcome between the two patellar mobilisation techniques. Methods We enrolled 41 patients who underwent bilateral simultaneous TKR (82 knees) from Nov 2016 to Dec 2018. During surgery patellar eversion was done in one knee and lateral retraction was done in other knee selecting them randomly to reduce the bias. During the follow up period achieving unassisted active straight leg raise (SLR), 90 flexion and complications were recorded. Measurement of Oxford knee society score (OKSS), American knee society score (AKSS), Visual Analogue Scale (VAS) score, and quadriceps strength (measured by handheld dynamometer) was done daily up to one week, 1 month, 3 months, 6 months, and 1 year postoperatively. Results The time of achieving active SLR and 90∗ flexion postoperatively was quicker in the lateral retraction group with a statistically significant difference. VAS pain score at 1 week and 1 month along with quadriceps strength in 1-month had statistically significant favourable outcomes in the lateral retraction group. Throughout the follow up lateral retraction group had better Oxford and American knee score but the difference being statistically insignificant. No significant difference was found on the complication rate. Conclusion In comparison to lateral retraction, patellar eversion has an adverse effect in early knee functional recovery after TKA; it delays achieving active SLR, 90∗ flexion and has unfavourable outcome in functional scores, quadriceps strength, and postoperative pain relief. However it has minimal effects on long term functional outcomes.