Clinical Results Associated with Changes of Posterior Tibial Slope in Total Knee Arthroplasty

PURPOSE The purpose of this retrospective study is to investigate the effect of posterior tibial slope (PTS) on clinical results in total knee replacement arthroplasty (TKA). MATERIALS AND METHODS We analyzed 801 knees in 768 patients who underwent TKA using a cruciate-retaining prosthesis for osteoarthritis from July 2003 to July 2009. PTS was measured on simple X-ray films and patients were divided into 5 groups, according to the change in PTS that was calculated by subtracting the preoperative from the postoperative PTS: group 1, >3°; group 2, 3° to 1°; group 3, 1° to -1°; group 4, -1° to -3°; and group 5, <-3°. We analyzed the correlations between the change in PTS and clinical results, such as Knee Society knee score, Knee Society functional score, Feller patella score, Kujala score, visual analog scale score, range of motion, and complications. RESULTS There was no statistically significant intergroup difference; however, Feller patella score and Kujala score were significantly different in groups 2 and 3. There were no complications, such as progressive loosening of implants, fractures of polyethylene inserts and wears. CONCLUSIONS Clinically meaningful improvement was observed in all patients after TKA. Groups 2 and 3 (3° to -1°) showed significant improvement compared to the other groups.