The International Society for Technology in Arthroplasty (ISTA) held its 29th annual meeting in Boston this weekend. There was a general sense of optimism regarding the forecast of soon-to-be released fully robotically controlled total knee arthroplasties (joint replacements).
In contrast to the high success rate of hip replacement surgery, replacement of the knee joint with an internal metal and plastic prosthetic component suffers from a good, but not great, reputation. Multiple publications known as meta-analyses, which pool multiple independent studies on the same topic, have concluded that up to 20 percent of patients who undergo knee replacement surgery are dissatisfied. This has prompted surgeons and engineers to develop better instruments to perform the surgery. As might occur in any other mechanical industry, attention has turned to the use of robots and sensors to improve performance.
For over 10 years, surgeons have used computer-assisted navigation or GPS technology during implantation to improve their orientation during the course of the procedure. The improved technology assists them in inserting the implant onto the bone surfaces from which the damaged cartilage has been trimmed. Recent large series reports, known as registry results, indicate that such technology reduces the chance of failure and the need for repeat surgery, especially in younger, more active patients.
Developments in robotic surgery have made possible an unprecedented level of precision in bone cuts and have proven successful in hip and partial knee replacements for several years. Two major manufacturers have launched their preclinical trials, indicating that full robotic surgery of the knee will be clinically available within a year.
Quality verification is the other attribute of precise automated work. This is where sensors come into play. For the last several years load sensors or pressure sensors have been inserted into knee implant trial components to be used at the time of surgery. These sensors can detect abnormalities in the magnitude or distribution of the forces across the knee, guiding the surgeon to correct any imbalance through selective maneuvers.
The potential combination of robots and sensors is appealing and exciting. It would allow the surgeon to quickly adjust any imbalance due to the soft tissues after performing the best possible bone cuts. Several clinical and benchtop studies are underway to prove the clinical merit of the concept.