Knees can fail for all sorts of reasons, from sports injuries to the creep of age. Modern medical technology is ready to help replace damaged joints with arthroplasty, a surgical specialty that restores joint function by resurfacing the bones or replacing a bad knee joint with an artificial one.
Patients may opt to have knee surgery when diagnosed with osteoarthritis, the degenerative joint disease. Damaged cartilage can no longer cushion and protect the knee bones. When bones rub on bone, the pain is excruciating and mobility is difficult to impossible.
Inflammatory arthritis, rheumatoid arthritis, general arthritis, obesity, and gout are all disabling and often painful conditions requiring a surgical remedy when non-operative treatments (such as activity modification, anti-inflammatory medications, or knee joint injections) fail to relieve the symptoms of arthritis.
The worst cases of degeneration may be resolved by a complete knee replacement, known as TKA: Total Knee Arthroplasty. In this invasive procedure, the surgeon makes a roughly 8-inch incision over the knee and implants the replacement joint. The patient needs inpatient hospital care for 3-5 days post-operatively. In some cases, additional time in an inpatient rehabilitation setting is needed before the patient can go home.
It can take up to another one to three months before a TKA patient can stop using a walker or cane. Knee replacement is a pain in the…knee.
Despite its cost and inconvenience, TKA is one of the most successful and common elective inpatient orthopedic procedures in terms of patient outcome (recovery, physical effectiveness of the procedure, and patient satisfaction). An artificial knee often lasts a good 15 to 20 years before it, too, breaks down and needs another replacement.
TKA procedures are estimated to total just shy of 3.5 MILLION by 2030 as baby boomers continue to age. Naturally, medical research and development are keeping pace with the increasing demand from people whose quality of life has slipped.
One innovation is a mobile-bearing TKA which “allows unimpeded freedom of the polyethylene inserted between the femur and tibia to rotate around a central post on a highly polished, cobalt-chrome tibial surface.” What this means, in plain English, is that a knee is not hinged like a fence. It does a lot more than swing back and forth. It can perform the “sagittal and rotational plane kinematic motions” of a human knee. Again, in plain English, this knee rotates and bends to imitate its human counterpart.
A new surgical option for TKA patients is minimally-invasive quadriceps-sparing (MIS) total knee replacement. The quadriceps are the most important muscle group surrounding the knee joints. To avoid traumatizing them with an 8-inch surgical cut, this technique uses an incision half that size, from 3-4 inches.
Not surprisingly, with reduced muscle trauma comes faster healing and a shorter recovery time requiring the assistance of a cane or walker – as little as two weeks after surgery or even less in some cases.
The new procedure appears to restore muscle strength and control sooner than those who had a traditional TKA. The smaller incision resulted in reduced post-op pain without sacrificing reliability of the implants.
There is a learning curve to MIS TKAs. The physician must operate through a smaller surgical window and this can take some getting used to.
One significant problem identified by arthroplastic experts was that one in five TKA patients reports an unsatisfactory outcome. Instead of having a bionic knee with superpowers, they experienced stiffness, loss in range of motion, and unstable knee joints. Over 55,000 revision surgeries are performed in the U.S. each year.
Improper soft-tissue balance and mal-alignment of the replacement joint caused about 40 percent of premature TKA implant failures, necessitating high-cost and inconvenient revision surgery.
To address ligament balancing technique to improve TKA outcomes, a company called Verasense, with corporate headquarters in Dania Beach, Florida, developed a disposable, intelligent Orthosensor Sensor-Assisted TKA which aims to improve surgical outcomes and patient satisfaction by providing “soft tissue balance and implant position through sensor-assisted technology used in primary and revision total knee replacement.”
This digital device slips between the knee joint during a TKA procedure. Its onboard sensors relay information wirelessly to an intra-operative monitor in real-time so the surgeon can target the best positions for the replacement knee. The system concept is much like that of balancing and aligning a car tire so it wears evenly.
Here’s how the Verasense Orthosensor works, according to Boone County Hospital in Iowa where surgeons have adopted the innovative orthopedic device:
“During surgery, the surgeon temporarily inserts VERASENSE between the components of the knee implant. As the knee is taken through a full range of motion, the sensor wirelessly sends data to a monitor in the operating room. This data helps the surgeon to make adjustments that affect soft tissue balance and implant position – two factors that contribute to a successful TKR. Once the implant position is stabilized, the sensor is removed and replaced with a permanent implant.”
If you’d like to get down on your knees to pray for better knees but can’t – because you need new knees – take heart and talk to your doctors about what’s new in orthopedic surgery.