Intraoperative medial joint laxity in flexion decreases patient satisfaction after total knee arthroplasty.
Academic Article
Overview
abstract
INTRODUCTION: The relationship between postoperative tibiofemoral ligament balance and patient satisfaction in total knee arthroplasty (TKA) has been explored previously. However, the optimal intraoperative medial-lateral ligament balance during knee flexion in terms of postoperative patient satisfaction remains unknown. We evaluated the effect of intraoperative flexion instability on patient satisfaction after TKA. MATERIALS AND METHODS: This study consisted of 46 knees with varus osteoarthritis undergoing TKA. Medial-lateral component gaps at 0° knee extension and 90° flexion were measured intraoperatively using a knee balancer. Differences in postoperative patient outcomes at 3 weeks and 1 year were compared between medially tight knees in 90° flexion with a medial component gap of < 4 mm and medially loose knees in 90° flexion with a gap of ≥ 4 mm. Outcomes were measured using the 2011 Knee Society Scoring System (2011 KS). RESULTS: The median total 2011 KS score at 1 year postoperatively in the medially loose knees [median 97; interquartile range (IQR) 75-117] was significantly lower than that in the medially tight knees (median 128; IQR 104-139, P < 0.01), while preoperative and 3-week postoperative scores were similar. In addition, medial flexion gaps were not significantly associated with total 2011 KS scores before surgery or at 3 weeks postoperatively. However, at 1 year after surgery, medial component flexion gaps were negatively associated with the total 2011 KS score (R = - 0.42; P < 0.01) and the 2011 KS satisfaction subscale score (R = - 0.36; P = 0.01). CONCLUSIONS: Excessive intraoperative medial joint laxity of ≥ 4 mm at 90° flexion progressively decreased patient satisfaction for 1 year. Since intraoperative medial laxity in flexion is likely to interfere with functional recovery after TKA, medial stabilization during TKA is important throughout knee flexion. LEVEL OF EVIDENCE: Therapeutic study, Level III.
