Abstract
Background
The combination of patient-specific “just-in-time” implant manufacture and robotic technology has not yet been reported. The robot enables accurate placement of anatomically-matched implants. It should be cost-effective, simplify the procedure, and reduce instrumentation. The aims of this study were to determine whether the procedure was safe, radiographically accurate, and comparable in time and cost to conventional arthroplasty.
Methods
All patients over 3 months post-op were included. Component position, orientation and size were determined from CT scans by the surgeon prior to manufacture. The implants were inserted using the Sculptor robot, which is supplied free of cost (Savile Row, Stanmore Implants, UK). Following registration, bone was milled away using a high-speed burr under haptic control of the robot. The implants were cemented and a mobile bearing inserted. Patients were followed up clinically and radiographically. Oxford and EQ-5D scores were obtained. Costs of the implant, instruments, and consumables were calculated and compared to published data for conventional UKA and TKA.
Results
17 patients (7M:10F) have reached 3 months follow-up. Mean age was 67 (range 49–84). Mean “robotic surgical time” was 25 minutes (range 14–39) contributing to a mean tourniquet time of 79 minutes (range 57–105). Median length of stay was 3 days (range 1–8). Post-op radiographs showed satisfactory component position. At a median follow-op of 4 months (range 3–6), mean Oxford score was 32 (range 23–41), and mean EQ-5DVAS was 70 (range 40–90). There were no serious complications. Total cost was £1665 per patient compared with £1334 for conventional UKA and £2620 for TKA.
Conclusions
Patient-specific UKA can be made and placed safely, with radiographical accuracy, using a “no-cost” haptic robot. The time taken is comparable to other knee arthroplasty procedures, uses less instrumentation, and costs £1000 less than a typical TKA.
