Open Wedge High Tibial Osteotomy with Distal Tubercle Osteotomy Lessens Change in Patellar Position

The purpose of this study was to investigate the change in patellar position after open wedge high tibial osteotomy (OWHTO) with distal tubercle osteotomy (DTO), comparing outcomes of conventional OWHTO in young adults with proximal tibia varus deformity but no arthritic manifestations. Thirty-three patients (mean age, 31.8 years) subjected to OWHTO/DTO were matched with 30 patients (mean age, 33.5 years) undergoing conventional OWHTO. Patellar position, as measured in pre- and postoperative standing lateral radiographs, was compared. Patellar height was assessed via Insall-Salvati ratio, modified Insall-Salvati ratio, Blackburne-Peel (BP) index, Caton-Deschamps (CD) index, and modified Miura-Kawamura index. Computed tomography was used to measure lateral patellar tilt and shift. In the OWHTO group, all patellar height indices decreased significantly following surgery. Although mean values of BP and CD indices decreased significantly in the OWHTO/DTO group, other determinants of patellar height showed no significant postoperative differences. Significant postoperative declines in average lateral patellar tilt were also evident in both groups, but pre- and postoperative lateral patellar shift did not differ significantly. OWHTO/DTO can be performed without significant changes in patellar height. The results obtained support that OWHTO/DTO is suitable for relatively young patients with proximal tibia vara but no arthritic change.