Robotic-Assisted Medial Epicondylar Osteotomy and Dual Fixation Technique During Total Knee Arthroplasty for Severe Varus Deformity.

We report a robotic-assisted sliding medial epicondylar osteotomy along with a transosseous dual-fixation technique to balance severe varus deformities that are not amenable to medial release during total knee arthroplasty. A 60-year-old woman with bilateral knee osteoarthritis and a varus deformity of about 50° (hip-knee-ankle angle: Right 133°, left 127°) underwent staggered, bilateral robotic-assisted total knee arthroplasty. Despite excising osteophytes, performing a complete medial release, a reduction osteotomy, and reconstructing the medial tibial defect with a 10 mm modular metal augment, a significant imbalance with 9.5° of varus deformity remained uncorrected. Therefore, a medial epicondylar osteotomy was performed. The osteotomy fragment was displaced distally and posteriorly under real-time robotic control to achieve equal flexion and extension gaps. Robotic workflow is also used to monitor alignment and gaps during component cementation and osteotomy fixation. A dual-fixation technique is described using 2 interfragmentary cannulated screws and 2 transosseous nonabsorbable sutures to counter the deforming forces. The osteotomies healed bilaterally at 8 weeks. After 9 months of follow-up, the patient reports no pain, walks independently, has a range of motion of 0° to 115° bilaterally, and has a hip-knee-ankle angle of 178° on the right and 179° on the left.