Abstract
Robotic-assisted devices help provide precise component positioning in conversion
of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA). A few
studies offer surgical techniques for computed tomography (CT) based robotic-assisted
conversion of UKA to TKA; however, no studies to date detail this procedure utilizing
a non-CT-based robotic-assisted device. This article introduces a novel technique
employing a non-CT-based robotic-assisted device (ROSA Knee System, Zimmer Biomet,
Warsaw, IN) for converting UKA to TKA with a focus on its efficacy in gap balancing.
We present three patients (ages 46–66 years) who were evaluated for conversion of
UKA to TKA for aseptic loosening, stress fracture, and progressive osteoarthritis.
Each patient underwent robotic-assisted conversion to TKA. Postoperative assessments
at 6 months revealed improved pain, function, and radiographic stability. Preoperative
planning included biplanar long leg radiographs to determine the anatomic and mechanical
axis of the leg. After arthrotomy with a standard medial parapatellar approach, infrared
reflectors were pinned into the femur and tibia, followed by topographical mapping
of the knee with the UKA in situ. The intraoperative software was utilized to evaluate
flexion and extension balancing and plan bony resections. Then, the robotic arm guided
placement of the femoral and tibial guide pins and the UKA components were removed.
After bony resection of the distal femur and proximal tibia, the intraoperative software
was used to reassess the extension gap, and plan posterior condylar resection to have
the flexion gap match the extension gap. The use of a non-CT-based robotic-assisted
device in conversion of UKA to TKA is a novel technique and a good option for surgeons
familiar with robotic-assisted arthroplasty, resulting in excellent outcomes at 6
months.
Keywords conversion total knee arthroplasty - unicompartmental knee arthroplasty - robotic-assisted
surgery
