Promising Results of Total Knee Arthroplasty in Patients with Severe Varus Deformity with High Constrained Prosthesis: A Prospective Study

Objectives: The existing literature does not provide a clear definition of the outcomes of total knee arthroplasty (TKA) and prosthesis constraint in patients with severe varus deformity. In this study, for the first time, we evaluated the outcomes of TKA and the relationship between prosthesis constraint and these outcomes in patients with severe varus deformity (>۳۰ degrees). Methods: This prospective cohort study was conducted on ۴۱ patients (۵۴ knees) with varus deformity greater than ۳۰ degrees who underwent TKA between April ۲۰۱۳ and April ۲۰۱۹. The patients were divided into two groups based on the type of prosthesis (high constraint and low constraint). Surgical outcomes were evaluated using the Knee Society Score (KSS), Oxford Knee Score (OKS), range of motion (ROM), and postoperative complications. Results: High-constrained prostheses (HCP) and low-constrained prostheses (LCP) were used in ۴۴ and ۱۰ knees, respectively. The mean follow-up duration was ۷۷.۱۱ ± ۶.۵۵ months. The mean KSS, KSS function, OKS, and ROM significantly improved after surgery compared to preoperative values (P<۰.۰۵). The mean improvement in the KSS function score after surgery was significantly higher in patients with HCP compared to those with LCP (p = ۰.۰۲۱). No significant differences were observed for the other variables. No cases required revision. Conclusion: This prospective non-randomized study, conducted on ۴۱ patients (۵۴ knees) with severe varus deformity (>۳۰º) who underwent total knee arthroplasty (TKA), demonstrated that the mean improvement in the Knee Society Score (KSS) function score after surgery was greater for high-constrained prostheses (HCP, N = ۴۴) compared to low-constrained prostheses (LCP, N = ۱۰). The HCP group included ۴۰ Legacy Constrained Condylar Knees (LCCK) and four hinged knee prostheses, while the LCP group included posterior-stabilizing (PS) prostheses. The mean follow-up duration was ۶.۵ years. Given the small sample size, randomized clinical trials are needed to validate our preliminary findings.         Level of evidence: III

کلیدواژه ها:

Constrained prosthesis ، Functional score ، Knee Osteoarthritis ، Severe Varus ، Total knee arthroplasty