Post-operative Patellar Tilt Affects Knee Society Score After Total Knee Arthroplasty at 2 Years Follow up

Abstract Introduction The effect of post-operative patella tracking on functional outcomes after total knee arthroplasty (TKA) remains unclear. Our study aimed to analyze the relationship of post-operative patellar tilt with functional outcome scores at 2 years after total knee arthroplasty. Methods Patient's data were retrieved from our institutions prospectively maintained TKA registry. 303 patients who underwent unilateral TKA from Jan 2012 to March 2017 were included in the study. After excluding patients with incomplete data and lost to follow up data for 231 patients were analyzed. Information was collected from pre-operative as well as post-operative skyline views and three functional outcome scores including SF-36, KSS, and WOMAC at pre-op, post-op 1 year, and post-op 2 years. Patella tilt (PT), patella displacement was calculated from radiology software in PACS. Patients were divided according to PT into 3 subgroups (PT < = 5 degrees, 5.1–10, > 10 degrees). Statistical analysis was done to identify the relationship of patella tilt and 3 functional. Results There was a significant improvement in post-operative patella tilt as compared to pre-operative patella tilt (3.35+-3.91vs5.65+-4.41, p-value = 0.0000). There was no significant difference in patella displacement in the postoperative period as compared to the pre-operative period. KSS functional score was significantly poor at 1 year and KSS objective score at 2 years in patients with PT more than 10 degrees. SF-36 and WOMAC were not significantly different in three subgroups based on PT. Conclusion Poor functional after TKA can be associated with an increase in patella tilt at 2 years follow up. Level of evidence: II