Abstract
A prospective study of 276 TKA's performed in patients with valgus knee deformity ≥ 10° using a Modified Surgical Technique.
MATERIALS AND METHODS
Bone cuts were used to balance the valgus knee and soft tissue release was confined to the postero-lateral capsule in severe deformity. The aim was to restore a “functional mechanical axis” as opposed to a “neutral” mechanical axis. All surgeries were performed between Jan2003 and Apr2007, under the care of a single surgeon using an LCS rotating platform. All patients had full length radiographs and outcome scores collected prospectively.
RESULTS
The mean coronal alignment of the lower limb was corrected from 15.9°(10-45°) to 3.8°. 94% patients had their coronal alignment restored to = 7°. Sixteen knees with postoperative valgus ≥8° were analysed as a separate group. The mechanical axis deviation was corrected from 52.3mm to 8.8mm. The distal femoral cut was made at 5° valgus in 131 knees(47.5%), 6° in 111 knees(40.2%) and 7° in 24 knees(8.7%).78 knees(28%) were balanced only with bone cuts. 198 knees(72%) had release of posterolateral capsule. 16 knees(5.8%) also had release of IT band. Lateral patellar release was performed in 39 knees (14%) and 23 knees had patella contouring. 93%knees had central patello-femoral alignment postoperatively. One spinout was managed by closed reduction and a second patient had revision of tibial tray for collapse. Patellar subluxation occurred in two patients. The oxford knee score and the American Knee Society clinical score improved from 48.5 to 26 and 21.04 to 86.03 respectively.
CONCLUSION
Adequate correction of valgus knee deformity was successfully achieved using our modified technique with satisfactory short term outcome. It is our opinion that the extensive release of soft tissues is not only unnecessary but also fraught with the potential for instability.
