Early results of total knee arthroplasty performed through the midvastus approach

The aim of this study was to evaluate the early results of total knee arthroplasty (TKA) performed through the midvastus approach.

This retrospective study included 48 knees of 42 patients (29 females, 13 males; mean age 69 years; range 54 to 82 years) who underwent TKA for grade 4 knee osteoarthritis. All TKA operations were performed by the same orthopedic surgeon through the midvastus approach. Preoperatively, 40 patients (95.2%) had primary osteoarthritis, and two patients (4.8%) had rheumatoid arthritis. In all cases, a posterior stabilized cemented prosthesis with a fixed insert was used. Patellar resurfacing was performed in seven knees (14.6%). All the knees were rated according to the Knee Society knee and function scores before surgery and at the final follow-up. Postoperative radiographic evaluations were performed on anteroposterior and lateral radiographs according to the Knee Society TKA Roentgenographic Evaluation and Scoring System. The mean follow-up period was 26 months (range 12 to 49 months).

The mean knee score significantly improved from 49.0+/-9.3 preoperatively to 87.5+/-9.9 postoperatively (p=0.000). The corresponding increase in the knee function score was from 48.8+/-9.9 to 79.6+/-14.0 (p=0.000). The mean increases in the knee and function scores were 38.5 and 30.8 points, respectively. The knee and function scores were excellent or good in 46 knees (95.8%) and 42 knees (87.5%), respectively. The mean knee flexion significantly increased by 28.6 degrees , from 84.3+/-14.7 degrees preoperatively to 112.9+/-11.9 degrees postoperatively (p=0.000). Among patients with bilateral osteoarthritis, the knee function scores were significantly higher in patients who had undergone bilateral versus unilateral TKA (90.0+/-11.5 and 78.8+/-10.8, respectively; p=0.007). None of the patients had patellar tracking abnormality intraoperatively; thus, there was no need for lateral retinacular release. Postoperative clinical and radiographic assessments showed no signs of instability or loosing. Clinical and radiographic loosening of the patella and osteolysis were not observed in patients who had undergone patellar replacement. No changes were observed in the tracking and position of the protheses. Neurovascular injury did not occur. One patient who developed early infection of the knee that required a two-stage revision was assessed as failure.

In our study, lateral retinacular release was not needed due to achievement of proper patellar tracking in TKA operations with the midvastus approach, and satisfactory clinical and radiographic results were obtained.