While joint replacement procedures are one of the most common elective surgeries in the United States, with total knee replacements expected to increase by 189% by 2030 and total hip replacement (TKR) by 171%, there is still room for improvement in how these surgeries are performed.
Studies show that up to 20% of patients are left unsatisfied after total knee replacement, begging the question, would robotic-assisted joint replacement offer patients better outcomes?
Many studies have weighed in on this question and while there are benefits to robotic-assisted total joint replacement, the jury is still out on whether the benefits are enough to justify the costs which is upwards of $1 million dollars. This is a big investment considering the pressure in today’s healthcare systems to reduce costs.
Researchers involved in one such study, “Comparison of conventional versus robotic-assisted total hip arthroplasty using the Mako system: An Italian retrospective study,” published March 2018 in the Journal of Health & Social Sciences, found the Stryker’s Mako Robotic Arm Assisted Technology did significantly decrease a patient’s hospital stay but did not find any significant differences in patient-reported outcome measures. Therefore, they recommended further long-term studies to justify additional costs.
Douglas E. Padgett, M.D., chief, Adult Reconstruction and Joint Replacement at the Hospital for Special Surgery in New York City, however, has found in his own research that despite cost concerns robotic-assisted total joint replacement does improve outcomes and that robotic technology is here to stay.
According to Padgett, in joint replacement there are still three main issues: bearing wear and failure, instability (largely in hip replacement) and patient satisfaction (largely in knee replacement).
Better Control Over Surgical Variables
Using a unicompartmental knee replacement (UKR) case study, he discussed how a robotic tool could improve how much control surgeons have over these issues.
“UKR is somewhat controversial. It has been said, ‘Only a doctor with half a brain would put in half a knee replacement,’” he said. “But if you look at UKR there are a lot of advantages.”
Some of the advantages include preserving the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL), low complication rates, a rapid return to work and possible cost savings. Researchers have also documented a high return to sport with more than 95% of patients returning to preoperative level of sports.
There are however durability concerns and the need for revision.. Variables that influence the outcome of UKR, according to Padgett, include: patient selection, implant positioning, fixation, lower limb alignment, proper sizing, implant design, whether inlay, onlay or mobile bearing and soft tissue balance
UKR failure, Padgett said, is often associated with technical error, with surgical technique having a dominant effect on outcome especially when it comes to avoiding over and under correction of lower limb alignment, attempting to reduce the varus angulation of tibial slope, and avoiding a posterior slope of implant greater than 7 degrees.
He pointed to an analysis of wear patterns on retrieved implants from non-robotic-assisted UKRs in “Unicondylar Knee Retrieval Analysis” published in the Journal of Arthroplasty on June 14, 2010. The wide variation of alignment found in the wear patterns on these implants suggests there is room for improvement.
