North Alabama Surgeons Use Custom Fitting Knee Replacements
Knees—large and small, knock-kneed and bowed--are as different as the people who stand on them. In fact, one study looking into knee anatomy found that 98% of its subjects had least some degree of variation from what is generally considered the norm.
Every year, American surgeons work to fit replacement joints into over 500,000 of those not-so-standard knees. This can be a time-consuming process, requiring on-the-spot adjustments and decision-making, as well as an operating room equipped for a broad range of possibilities.
In the past two years, however, several Alabama surgeons have been using a process that allows them to do much of the surgical planning, decision-making and fitting in advance with great precision using the OtisKnee® technique from OtisMed Corporation.
"With this approach, we start with an MRI image of the patient's knee and send it to OtisMed, where their software generates a computerized 3-D virtual model of the corrected knee," said Kenneth Bramlett, MD of Orthopaedic Sports Medicine Clinic of Alabama. "Then the computer matches a 3-D image of the implant to the virtual knee. From this, they create a custom cutting guide based on the patient's specific anatomy. Surgeons then use the guide to assist in making very accurate bone cuts and placing the implant to give the patient the best results."
Bramlett, who helped to proof out the system during its development, now uses Otisknee in about a third of the total knee replacements he performs at Brookwood Medical Center.
"It requires more up-front preparation, more office visits, and more coordination, but it saves time in the operating room," Bramlett said. "Patients spend less time under anesthesia, and they usually feel more stable right away, particularly side-to-side stability. If one leg is bowed, we can decide whether to match the bowed alignment or go straight, depending on whether we're doing one leg or both, to restore the best functional symmetry and make sure the legs are equal in length. There's not as much dissection exposure, so, depending on the patient's other issues, recovery time can be faster. We usually have patients up and taking their first steps within two to three hours the same day.
"I can usually do the Otisknee procedure in less than an hour versus an hour and a half with a traditional knee replacement. It's like the difference between setting up tables and place settings for a banquet and cleaning up after versus using paper plates. With less prep and cleanup time, the OR is available for more procedures per day. Not having to setup and resterilize so many extra trays also saves on costs."
Across the state in Huntsville, Kendall Black, MD of SportsMED Orthopaedic Surgery and Spine Center is using the Otisknee approach in most of his total knee replacements.
"We usually do the MRI three weeks in advance," Black said. "That image is used with computer design to create a cutting guide that helps us select more accurate cuts in the bone, and helps us get better alignment for that specific patient's unique anatomy. I try to use it on all my total knee replacements in patients who can tolerate an MRI.
Black is happy, thus far, with the results patients have experienced. "The post-op pain levels seem to be lower and shorter in duration, and the rehab tends to go faster," he said. "There are variations in patients, of course, but most seem to get a quicker return to function. With the Otis-Knee, we can incorporate the prosthesis in a way that is cruciate-sparing and less invasive. That's probably one reason there is better initial stability and less pain. This approach has been so successful that quite a few other companies are now working on a similar technique."
Bramlett added that although the OtisKnee technology is currently available only for total knee replacement, extended applications are now in development. "OtisMed is also working on a similar approach to use in hip and shoulder procedures," he said. "The shoulder procedure is now in the final stages of research, and the hip is in clinical trials."
In a UAB study evaluating the OtisKnee Custom Fit Knee™ Replacement System, lead investigator Herrick Siegel, MD, who performed the first procedure using the system in Alabama at UAB Highlands in the summer of 2007, reported that the technique may have a positive impact on length of hospital stay, range of motion, pain level and patient satisfaction immediately following total knee replacement surgery. The study found that the average length of hospital stay for OtisKnee patients was 2.2 days for a single knee replacement, and 3.5 days for bilateral surgery. At two weeks, 17 of 19 patients were walking with only a cane, and 16 of 19 reported that they only needed prescription pain medication for 10 to 14 days after surgery.
Now that the OtisKnee technique has been used in more than 10,000 total knee replacements nationwide, the response from both surgeons and patients has been generally positive. The less invasive approach preserves more of the patient's own bones and ligaments and reduces blood loss and scarring. It also fits in with a growing trend toward minimum incision surgeries that return patients more quickly to their normal activities.
Another concept Bramlett is using to speed recovery in his orthopaedic surgery patients is a concept he calls "pre-habilitation."
"If you were running a 10K race, you wouldn't just go out there and start running," Bramlett said. "You'd train by pre-racing. We like to get our patients up to speed mentally and physically by working with them six to eight weeks before surgery. Aggressive pre-op preparation and post-op rehabilitation helps us get better outcomes.
With total knee replacements expected to increase to 3.4 million per year by 2030, techniques that result in better outcomes and more efficient surgeries will meet a growing need in years to come.