Bicompartmental osteoarthritis involving the medial tibiofemoral and the patellofemoral compartments is often treated with total knee replacement. Improved implants and surgical techniques have led to renewed interest in bicompartmental arthroplasty. This study evaluates the radiographic and early clinical results of bicompartmental arthroplasty with separate unlinked components implanted with the assistance of a robotic surgical arm. In addition, we examine the amount of bone resected using unlinked bicompartmental components compared to total knee replacement. Finally, a retrospective review of total knee cases examines the applicability of this early intervention procedure. 97 patients received simultaneous but geometrically separate medial tibiofemoral and patellofemoral arthroplasties with implants specifically designed to take advantage of a new bone and tissue sparing implantation technique using haptic robotics. These patients came from four surgeons at four different hospitals. The average follow-up was 9 months. Pre- and post-operative radiographs were taken. ROM, KSS and WOMAC scores were recorded. The patients had an average age of 67 yrs (range: 45-95), BMI of 29 ± 4kg/m2. 47% of the patients were male. We retrospectively reviewed pre and post operative notes from 406 consecutive TKA patients from a single surgeon. Intraoperative data included the integrity of the three compartments and the ACL.Introduction
Methods
Unicompartmental knee arthroplasty is realizing a resurgence due to factors such as improved alignment and sizing of components during surgery. This study compares the early results of two implantation techniques – robotic-assisted and standard manual alignment guides – to evaluate how a new technology developed to improve accuracy affects early patient outcomes. For this study, we chose a prospective consecutive series of 20 patients in each group to receive a medial unicompartmental knee arthroplasty. The patients were evaluated clinically using standard outcomes measures (Knee Society, WOMAC and Oxford scores) as well as for modes of failure. Average follow-up for the manual onlay technique was 12 months and for the robotic-assisted inlay technique was and 10 months. Patients were not statistically different in terms of BMI, age, or diagnosis (p>
0.05). Knee society score (p=0.65), total WOMAC score (p=0.75) and Oxford knee score (p=0.88) were not statistically different between the three groups. Five patients in the robotic-assisted inlay group complained of persistent tibial pain that resolved in four patients. There were no revisions for the manual onlay implant group and there was one revision for persistent tibial pain in the robotic-assisted inlay group, consisting of a conversion to a standard manual onlay UKA tibial component. Patient outcomes were similar with inlay robotic-assisted unicompartmental knee arthroplasty compared with conventional manual onlay implant techniques. Roboticassisted inlay components resulted in slightly increased complaints of tibial pain and had one revision for tibial pain, however the revision was to a standard onlay UKA tibial component.
