Robot assistance simplifies placing patient-specific UKA prostheses in pilot study
MANCHESTER — A new robotic device led to placement of unicompartmental knee arthroplasty implants matched to the patient’s anatomy that exceeded the accuracy of placements involving traditional procedures and components, according to results of a pilot study presented at the British Orthopaedic Association Congress 2012, here.
Barry L. Andrews, FRCS (Tr & Orth), presented findings of a research project he worked on with colleagues at Imperial University MSK Lab in London.
“Our ‘uni’ is time efficient. It is cost-effective. Our functional results are promising and our accuracy has been confirmed by CT analysis,” Andrews said.
Barry L. Andrews
He and colleagues studied 29 patients at Charing Cross Hospital with 3-months minimum follow-up that received a patient-specific unicompartmental knee arthroplasty (UKA) prosthesis implanted with assistance from the new Sculptor Robotic Guidance Arm (Stanmore Implants; Elstree, United Kingdom). They have performed 40 such cases to date, and thus far 21 patients have reached 6 months follow-up, according to the abstract.
Preoperatively surgeons made operative plans for all these cases using input from CT scans that guided component position, orientation and selection of component size. Intraoperatively the surgeon holds the burr used to remove bone, but the robot provides haptic and visual feedback, Andrews said.
“Our postoperative radiographs showed satisfactory component position and limb alignment,” he said.
The average duration of surgery per case was 70 minutes, which Andrews said was 10 minutes faster than surgical times for 3,000 cases recorded in the New Zealand Joint Registry.
“Our 10 minutes difference was significant,” he said.
The robotic “surgical” time per case was about 32 minutes.
The robotic arm and related software was provided cost-free from the manufacturer, he said. The median hospital length of stay was 3 days, which ranged from 1 day to 8 days. Two complications occurred in the robot-assisted patient-matched UKA cases, one each on the femoral and tibial sides. The femoral-side complication, which was an aseptic loosening, resulted in a revision.
Andrews BL, Aqil A, Manning V, Cobb J. Robot-assisted, patient-specific, unicompartmental knee arthroplasty: a pilot study. Paper #71. Presented at the British Orthopaedic Association Congress 2012. Sept. 11-14. Manchester.
Disclosure: Andrews received support for his research from Stanmore Implants.