Management of failed UKA to TKA: conventional versus robotic-assisted conversion technique

Abstract

Background: Failure of unicompartmental knee arthroplasty (UKA) is a distressing and technically challenging complication. Conventional conversion techniques (CCT) with rods and jigs have produced varying results. A robotic-assisted conversion technique (RCT) is an unexplored, though possibly advantageous, alternative. We compare our reconstructive outcomes between conventional and robotic methods in the management of failed UKA. Methods: Thirty-four patients with a failed UKA were retrospectively reviewed. Patients underwent conversion total knee arthroplasty (TKA) with either a CCT or RCT. Seventeen patients were included in each group. All procedures were done by a single surgeon at a single institution, with a mean time to follow-up of 3.6 years (range, 1 to 12). The primary outcome measures were the need for augments and polyethylene thickness. Secondary outcome measures were complications, need for revision, estimated blood loss (EBL), length of stay, and operative time. Results: The mean polyethylene thickness was 12 mm (range, 9 to 15) in the CCT group and 10 mm (range, 9 to 14) in the RCT groups, with no statistical difference between the two groups (P = 0.07). A statistically significant difference, however, was present in the use of augments. In the CCT group, five out of 17 knees required augments, whereas none of the 17 knees in the RCT group required augments (P = 0.04). Procedurally, roboticassisted surgery progressed uneventfully, even with metal artifact noted on the preoperative computerized tomography (CT) scans. Computer mapping of the residual bone surface after implant removal was a helpful guide in minimizing resection depth. No further revisions or reoperations were performed in either group. Conclusions: Robotic-assisted conversion TKA is technically feasible and potentially advantageous. In the absence of normal anatomic landmarks to guide conventional methods, the preoperative CT scans were unexpectedly helpful in establishing mechanical alignment and resection depth. In this limited series, RCT does not seem to be inferior to CCT. Further investigation of outcomes is warranted.

Utilization of Robotic Arm Assistance for Revision of Primary Total Knee Arthroplasty: A Case Report

“…The use of robotic assistance in revision knee arthroplasty is not yet licensed or approved by the FDA. The success of this case report, as well as previous studies describing robotics in revision knee arthroplasty [ 7 , 8 ] questions if this will happen. With frequent advances in robotic technology and software capabilities, the potential for better operative outcomes and broader indications with robotic assistance appears to be increasing.…”

“…Also in 2020, Yun et al presented the first case series of 34 failed UKAs, half of which were converted robotically to TKA, and half converted manually [ 8 ]. No revision components were used in either group.…”

“…There is a paucity of literature on robotic-assisted rTKA including just one case report [ 7 ] and one retrospective review [ 8 ]. All previous studies demonstrated the use of robotics in conversion of failed UKA to TKA.…”

Imageless robotic-assisted revision arthroplasty from UKA to TKA

“…Additionally, the robotic-assisted approach enables the intraoperative control of soft tissue balance, which might support the use of standard primary implants and minimum size PE onlays instead of constrained implants and onlays. In this context, image-based robotic-assisted UKA revision also showed comparable and a tendency towards lower PE thickness compared to manual UKA revision in a recently published study [ 30 ]. Alignment parameters were not analyzed in that study.…”

Revision Total Knee Arthroplasty Using Robotic Arm Technology

“…A small series by Yun et al. in 2020 has demonstrated that using computed tomography (CT)-based robotic-assisted surgery for conversion of UKA to TKA did not result in inferior outcomes [ 14 ].…”