Focal dome condylar osteotomy: Early results of alignment of a combined intra- and extra-articular high tibial osteotomy

Abstract

Background and Aims: Extra-articular high tibial osteotomies reliably treat varus deformities seen in medial compartment osteoarthritis of knee (MCOA). Recently, attention has turned to the detection and treatment of intra-articular knee deformity to treat MCOA. Tibial condylar valgus osteotomy (TCVO) is an intra-articular osteotomy (IAO) that corrects the varus by elevating the medial tibial condyle and is fixed with a plate. TCVO improves joint line convergence angle (JLCA), spine edge angle (SEA), and spine vertical distance (SVD), which measure intra-articular deformity. It may undercorrect the mechanical axis to <50%. Focal dome condylar osteotomy (FDCO) is recently described and claims to correct both the intra- and extra-articular deformities in MCOA. We aimed to study the immediate results of FDCO and compare its efficacy with TCVO. Patients and Methods: We performed ten FDCO procedures on ten patients over the last year. The mean age was 57 years. We compared the results with a similar retrospective cohort of ten TCVO patients. Results: The mean preoperative (bo) mechanical axis deviation (MAD) in FDCO was −13.8% and improved to 51.6%. TCVO group had a similar mean postoperative (po) MAD of 43.5% (P = 0.38). Although 6 of 10 FDCOs had MAD >50%, only two of TCVOs crossed the midline. The mean bo medial proximal tibial angle in FDCO was 85.9° and improved significantly po to 93°. Hip knee ankle angle, ankle joint line orientation, and knee joint line orientation improved significantly as did JLCA, SEA, and SVD. Condylar plateau angle did not change. Conclusion: FDCO is an IAO with a vertical limb that passes through the lateral tibial spine and a medial curved limb. This single osteotomy can correct the intra-articular and extra-articular varus deformity. Although there was no significant difference in the correction of intra- and extra-articular deformity parameters between FDCO and TCVO, we feel that it was part of our learning curve. FDCO has the potential for better correction of the mechanical axis along with intra-articular deformities.