[Clinical effect of one-stage total knee arthroplasty for knee osteoarthritis with femoral extra-articular deformity]

Objective: To investigate the application and efficacy of the one-stage total knee arthroplasty (TKA) of intra-articular compensation osteotomy in knee osteoarthritis(KOA) patients with extra-articular deformity (EAD). Methods: A retrospective study of 9 patients with end-stage KOA and EAD undergoing one-stage TKA from January 2014 to December 2017 in the First Affiliated Hospital of Zhejiang Chinese Medical University was performed. There were 3 males and 6 females with an average age of 56 years(range, 19-77 years);5 cases of simple coronal deformity (varus 10°-27°, mean 18.2°), 3 cases of sagittal deformity (recurvatum15°-35°, mean 22.6°), 1 case combined with coronal and sagittal deformity (varus 16°, recurvatum 31°); hemophilia dysplasia in 1 case, fracture malformation in 8 cases. Main outcome measures included the mechanical axis, range of motion (ROM) and Hospital for Special Surgery Knee Score (HSS). Results: The mean follow-up period was 33.2 months (range, 25-47 months). The mechanical axis angle was restored from 12.4°±4.1°to 1.4°±0.9°(t=7.954, P<0.01). The HSS was improved from 28±14 preoperatively to 87±7 postoperatively (t=-11.174, P=0.013). The ROM increased from 56°±22°to 99°±8° (t=-5.480, P=0.010). There was no complications such as joint instability, infection, fracture, common peroneal nerve injury and early prosthesis loosening. Conclusions: For KOA patients with femoral EAD, one-stage TKA with intra-articular compensatory osteotomy can effectively restore the mechanical axis and obtain satisfying joint function. Through a series of measures such as preoperative measurement, soft tissue evaluation and 3D printing, the accuracy of surgery can be improved and the difficulty of surgery can be reduced.