Total knee arthroplasty and extra-articular deformity: Deformity correction with intra-articular bone resections. 10 years follow up

Abstract

BackgroundThis study aimed to evaluate the feasibility and clinical results of one stage total knee arthroplasty for patients with knee osteoarthritis with extra-articular femoral or tibial deformity, treated with intra-articular bone resections and soft tissue balance for deformity correction. Methods28 patients (29 knees) with osteoarthritis of the knee associated with extra-articular deformity >10° underwent one-stage total knee arthroplasty from 1997 to 2017. The deformity was corrected in all the patients by mean off the intra-articular bone resections and soft tissue release during the knee arthroplasty. 14 of them had tibial deformities, 15 had femoral deformities, and the etiology was post traumatic in 14 cases and post osteotomy in 15. The Knee Society Score was used to evaluate the patient outcome. ResultsOne-stage total knee arthroplasty with intra-articular correction of the limbs extra-articular deformity and soft tissue releases to balance the knee in flexion and extension was performed in all the patients.The average follow up was of 10.3 years. The average Knee Society Score was of 24.3 points preoperatively and 86 points at one year after surgery. The range of motion improved from 83.7° preoperatively to 107.1° (86°–125°) postoperatively. The average mechanical axis deviation was restored from 11.8° preoperatively to 0.9° postoperatively, and the postoperative average anatomical axis was 6.3°. Two prosthesis were revised, one due to deep infection and one because knee instability. ConclusionThe correction of the extra-articular deformity by intra-articular bone resections performed at the time of a total knee arthroplasty is indicated if the resections do not affect the femoral or tibial insertions of the collateral ligaments of the knee, and is the treatment option to avoid performing an osteotomy to correct de limb axis. This method can be applied to angular deformities up to 20° in the femur and up to 30° in the tibia. Through this technique we have achieved good results, after more than 10 years of follow up, in 27 of the 29 patients treated.This is a retrospective level 2 study.