Salvage lateral open-wedge high tibial osteotomy for a multiplanar deformity after failed high tibial osteotomy for cosmesis : a case report and literature review

Background Most failed high tibial osteotomy (HTO) ultimately proceed to conversion to total knee arthroplasty; therefore, revision HTO is rarely performed, and revision lateral open-wedge HTO (LOWHTO) is even rarer. We report a rare and technically demanding case of revision LOWHTO for a complex multiplanar deformity following failed HTO for cosmesis, achieving deliberate triplanar correction including coronal varization, posterior tibial slope reduction, and tibial internal derotation. This case also introduces posterolateral menisco-tibial subsidence (PLMTS) as a previously undescribed pathomechanism. Case presentation A 40-year-old woman presented with worsening right knee pain and an externally rotated gait with subtle foot drag during the terminal stance phase, 20 years after undergoing lateral closed-wedge HTO for cosmesis. Preoperative evaluation revealed excessive valgus deformity (8.2° valgus and MPTA 95.0°), increased PTS (19.6°), excessive tibial external rotation (35.8°), reduced tibiofibular height difference and proximal tibiofibular osteosynthesis. MRI showed intact articular cartilage and meniscus in the knee joint. Diagnostic arthroscopy revealed substantial PLMTS. Revision LOWHTO with triplanar correction (varization, slope reduction, and internal derotation) was performed. Postoperative arthroscopy demonstrated marked restoration of the previously abnormally widened posterolateral gap. Postoperative radiographs showed improvements in coronal alignment (MPTA (87.7°), PTS (12.0°), and tibial external rotation (26.1°). At the 1-year follow-up, the patient demonstrated significant functional improvement with a notable reduction in pain and gait abnormalities. Conclusions This case demonstrates that salvage LOWHTO is a valuable joint-preserving solution for complex multiplanar deformities after failed HTO. When multiple technical maneuvers are appropriately integrated, simultaneous and intentional control of coronal, sagittal, and axial alignment becomes feasible, even in challenging scenarios. Furthermore, this case identifies a previously undescribed pathomechanism, PLMTS, resulting from unipolar correction of the proximal tibia relative to the fibula, providing additional insight into the biomechanical sequelae of failed lateral closed-wedge HTO.