Minimally invasive unicompartmental knee replacement: Midterm clinical outcome.

Shaoqi Tian,Chengzhi Ha,Wanqing Yuan,Lun Liu,Qicai Li,Kang Sun,Xu Yang,Jiangjun Liu,Yuanhe Wang,Gayle E Woloschak

doi:10.1371/journal.pone.0176082

Abstract

ObjectiveThe purpose of this study was to explore the midterm clinical outcomes of unicompartmental knee replacement (UKR) for medial knee arthropathy through a minimally invasive approach (MIA).MethodsFrom January 2006 to June 2010, 442 consecutive patients (485 knees) were included in the study. All patients underwent MIA-UKR with the mobile bearing Oxford phrase III prosthesis. The incision was made starting 1 cm medial to the medial pole of the patella and extending distally to the tibial tubercle. Radiographic evaluations include femorotibial angle (FTA) from coronal x-rays and rectified varus deformity angle, while clinical evaluations included Knee Society Score (KSS, clinical score and function score), the Western Ontario and McMaster Universities Arthritis Index (WOMAC) osteoarthritis index and visual analog scale (VAS) for pain. Patients followed-up at 1, 3, 6, 12 months after surgery and each year thereafter.ResultsFour hundreds and two patients completed the entire follow-up, 40 patients (45 knees) were lost to follow-up. The average follow-up time was 73.0 ± 1.9 months. The mean length of the incisions was 5.0 ± 0.2 cm. The average FTA decreased from 183.6° ± 5.1° preoperatively to 174.3° ± 4.2° postoperatively, and the mean rectified varus deformity angle was 9.3° ± 1.2°. The KSS clinical score improved from 42.4 ± 2.9 to 92.9 ± 3.8, and the function score improved from 53.5 ± 3.8 to 93.5 ± 4.0. The WOMAC score improved from 47.5 ± 3.1 preoperatively to 12.3 ± 1.5 at the last evaluation. The VAS dropped from 7.8 ± 1.9 preoperatively to 1.6 ± 0.2 postoperatively. All clinical evaluations (KSS, WOMAC, VAS) were significantly different (p < 0.05) from pre and post-operative evaluations. The survival rate was 99.1% at 73 months, and the revision rate was 0.9%.ConclusionThe midterm clinical outcomes of MIA-UKR are satisfactory in a Chinese patient population, which is a good surgical option for patients with medial arthropathy of the knee. However, longer-term follow-up studies should be performed in these patients.

Highlights

In 1973, the first study using unicompartmental knee replacement (UKR) for the treatment of knee osteoarthritis (OA) was reported by Marmor
The average femorotibial angle (FTA) decreased from 183.6 ̊ ± 5.1 ̊ preoperatively to 174.3 ̊ ± 4.2 ̊ postoperatively, and the mean rectified varus deformity angle was 9.3 ̊ ± 1.2 ̊
The Knee Society Score (KSS) clinical score improved from 42.4 ± 2.9 to 92.9 ± 3.8, and the function score improved from 53.5 ± 3.8 to 93.5 ± 4.0

Summary

Introduction

In 1973, the first study using unicompartmental knee replacement (UKR) for the treatment of knee osteoarthritis (OA) was reported by Marmor. There is still controversy regarding the role of UKR in the treatment of OA for more than four decades [1,2]. UKR were performed with traditional incisions used during total knee arthroplasty. Invasive approaches (MIA) have been more recently utilized and are differentiated by traditional approaches. While other studies have compared traditional to MIA [3,4,5], those studies have not report on the outcomes of MIA-UKR in Chinese patients. The purpose of this clinical study was to report the midterm clinical outcomes of MIA-UKR for Chinese patients with medial arthropathy of the knee

Methods

Results

Conclusion