Correction of severe varus deformity in total knee arthroplasty with the technique of tibial plateau reduction

Background

The optimal soft tissue release technique for severe varus total knee arthroplasty (TKA) remains controversial. The technique of tibial plateau reduction was suggested for severe varus deformity during TKA. The purpose of this study was to evaluate the clinical and radiological outcomes of the technique of tibial plateau reduction.

Methods

Fifty-one knees (39 patients) with a mechanical femoro-tibial angle (MFTA) greater than 15° treated with TKA was presented. The clinical and radiographic data were gathered prospectively. The patients were divided into two groups according to the preoperative angle: Group A comprised patients with a preoperative MFTA less than or equal to 20°, while Group B included patients with a preoperative MFTA greater than 20°.

Results

Among the 51 knees, 46 knees (90.2%) had femoro-tibial component size mismatch. The KSS-KS improved from preoperative 39.9 ± 11.3 points (range:18–68 points) to 92.3 ± 5.2 points (range: 83–100 points) at the final follow up (t = 30.141, P < 0.001); the KSS-FS improved from preoperative 48.0 ± 11.5 points (range: 31–71 points) to 87.2 ± 8.7 points (range: 63–100 points) at the final follow up (t = 19.413, P < 0.001). The mean MFTA was corrected from 21.0 ± 4.7° preoperatively to 2.9 ± 1.8° at the latest follow up (P < 0.001). The preoperative MFTA was less than or equal to 20° in 27 knees (Group A), and greater than 20° in 24 knees (Group B). The mean postoperative MFTA was 1.9 ± 0.9° in Group A, and 4.1 ± 1.7° in Group B (P < 0.001). The neutral limb alignment was reached in 26 knees (96.3%) in group A, which was significantly higher than that in group B (29.7%) (P = 0.019).

Conclusions

The technique of tibial plateau reduction provided satisfactory clinical and radiological outcomes without instability for severe varus TKA. However, surgeons should remain aware that the greater the preoperative varus deformity, the greater the postoperative residual varus deformity, and that there is a high incidence of femoro-tibial component size mismatch using the technique.