Intraoperative robot-guided femoral osteotomy during robot-assisted total knee arthroplasty for knee osteoarthritis with extra-articular deformity: a case report.

OBJECTIVE

To describe the short-term feasibility of using a CT-based robotic total knee arthroplasty (TKA) platform to plan and guide an intraoperative corrective femoral osteotomy when trial implantation revealed mechanical impingement in a patient with severe extra-articular femoral deformity.

DESIGN

A 60-year-old woman with end-stage knee osteoarthritis, 42° anterior femoral bowing, and a local 17° coronal valgus deformity underwent robot-assisted TKA. Corrective osteotomy was not included in the preoperative plan. After trial implantation produced a 20° extension deficit because of impingement between the polyethylene insert and the anterior femoral flange, the procedure was modified intraoperatively. The same TiRobot Recon-II platform (TINAVI, Beijing, China) was used to plan and guide a 20° anterior closing-wedge osteotomy at the deformity apex, followed by dual-plate fixation and definitive implantation of a posterior-stabilized resurfacing prosthesis.

RESULTS

The operation lasted 142 min, with an estimated blood loss of 200 mL. Full weight-bearing began on postoperative day 3. Knee range of motion was 0°-130° at 1 month and 0°-135° at 5 months. Postoperative full-length radiographs showed an HKA of 178.7°, corresponding to 1.3° of residual varus, and a MAD of 2.5 mm medial to the knee center. At 5 months, radiographs demonstrated osteotomy union, stable fixation, and maintained correction of limb alignment. The Knee Society Score improved from 29 to 91, and the Knee injury and Osteoarthritis Outcome Score pain subscale improved from 38 to 89. No wound, neurovascular, or implant-related complications were observed during the short follow-up period.

CONCLUSIONS

In this single case, intraoperative conversion to robot-guided femoral osteotomy during robot-assisted TKA was technically feasible and was associated with favorable early clinical and radiographic outcomes. These findings support short-term feasibility only and do not establish superiority over planned simultaneous or staged strategies. Larger studies and longer follow-up are required.