Total knee replacements -- or total knee arthroplasties (TKA) have become one of the most performed orthopedic surgeries in the world. According to the Agency for Healthcare Research and Quality, in 2017, more than 754,000 knee replacements were performed in the United States. In the PT clinic I treat as many patients after total knee replacements as any other orthopedic surgery. In orthopedic healthcare, total knee replacements are widely regarded as one of the most successful surgeries. The AAOS notes that over 90 percent of replacement knees are still functioning after 15 years.
Knee replacements are most often done when a person’s knee joint develops severe arthritis. This is when the cartilage in the knee joint -- at the bottom of the femur (“thigh bone”) and the top of the tibia (“shin bone”) -- degrades and the joint becomes painful and usually inflamed. Cartilage acts as padding in the knee joint and to decrease friction as the knee moves. When a person loses most of the cartilage in the knee this can be described as “bone on bone” arthritis and can require a TKA. Most of the time this loss of cartilage is due to wear and tear and is described as osteoarthritis. In some cases this can be caused by an inflammatory condition called rheumatoid arthritis or trauma like a motor vehicle accident.
Knee replacement surgery was first performed in 1968. Since then, improvements in surgical materials and techniques have greatly increased its effectiveness. Recently more and more surgeons are utilizing robotic guided surgical techniques and generally with excellent outcomes.
In a traditional TKA the surgeon uses preoperative x-rays, intraoperative anatomical landmarks, and manually positioned alignment jigs to guide bone cutting and implant positioning. These handheld techniques can lead to less reliable alignment-guide positioning, inadvertent sawblade injury to the knee muscles and ligaments, and limited ability to fine-tune the implant positioning. Suboptimal implant positioning may lead to poor functional recovery and reduced implant survivorship. (At this point I should note that I work with many surgeons who have done hundreds or thousands of these traditional TKAs with great clinical outcomes.)
Robotic TKA uses computer software to convert anatomical information into a virtual patient-specific 3D reconstruction of the knee joint. The surgeon uses this virtual model to plan optimal bone cutting and implant positioning based on the patient’s unique anatomy. An intraoperative robotic device helps to execute this preoperative patient-specific plan with a high level of accuracy. The action of the sawblade is confined to the preoperative surgical plan which limits soft-tissue injury and bone trauma.
A 2019 systematic review about robotic total knee replacement found the following:
If you are considering getting a TKA there is clearly a lot of evidence that robotic TKA are effective and in some ways superior to a traditional TKA. That being said, there are many other factors to consider when looking for a surgeon to do your TKA including:
Once you've made your decision don't forget the importance of rehab! All of our physical therapists are experts in both pre and post op knee replacement rehab. For more information about what to do once you've made this big decision, check out this informational page and reach out to one of our clinics to set up an appointment!
Eric Hanyak, PT, DPT
Bob Cranny, PT