Can osteoarthritic patients with mild varus deformity be indicated for high tibial osteotomy?

Background: Whether osteoarthritic patients with mild varus deformity can be indicated for high tibial osteotomy (HTO) is not established. We examined the preoperative characteristics and postoperative outcomes of HTO in patients with mild genu varum compared to patients with greater varus deformity. Methods: Seventy-one patients who underwent HTO were included in this retrospective study. Patients were divided into either mild varus (MV, mechanical femorotibial angle (mFTA) n = 31 (44%)) and greater varus (GV, mFTA >4 degrees, n = 40 (56%)) groups. Preoperative characteristics on single photon emission computed tomography-computed tomography (SPECT-CT), magnetic resonance image and radiograph were evaluated. Alignment parameters and functional outcomes were compared pre- and postoperatively between the groups. Results: Preoperative characteristics were similar between the two groups, except the severity of arthritis and coronal alignment. There was no difference in the proportion of hot uptake in the medial compartment; medial meniscus posterior horn root tear, complex or radial tear; bone marrow edema. Full-thickness cartilage defect of medial compartment was more frequent and arthritis grade was also more severe in GV group. Coronal alignment of the MV group was corrected into more valgus than the GV group (4.5 degrees vs. 2.8 degrees in mFTA, P = 0.012). Pre- and postoperative Knee Society knee and function scores were also comparable in the two groups. Conclusions: Mild varus patients are similar to greater varus patients regarding preoperative features and achieve the comparable functional outcome. A selected subset of osteoarthritic patients with mild varus deformity might be indicated for HTO. Level of evidence: Ill (Retrospective comparative study). (C) 2018 Elsevier B.V. All rights reserved.