Dorothy Frost was in her 50s when arthritis attacked both her knees, making it a painful chore to walk even the shortest distance.

Her symptoms didn’t respond to anti-inflammatory medications and other non-surgical therapies, but the damage to her knees wasn’t extensive enough to warrant a total knee replacement.

Like other patients whose arthritis is confined to one compartment of the knee, Frost and her orthopedic surgeon, Terry Clyburn, M.D., director of total joint research at The University of Texas Medical School at Houston, decided that a uni-compartmental device was the best option for relieving her pain. That was more than 10 years ago.

The uni-compartmental device is designed to restore limb alignment, relieve pain, improve knee function and prevent or delay the need for a total knee replacement. The ideal candidate is someone who is between the ages of 50 and 60 who is healthy and expected to live 20 to 25 more years.

“This technique fills a much-needed gap,” says Michael Mann, M.D., assistant professor in the Department of Orthopaedic Surgery at the medical school.

Attractive Surgical Option

If a person didn’t respond to anti-inflammatories, activity modification, physical therapy, bracing or joint injections, there wasn’t much left to do. “The only options we really had to offer in the past were arthroscopy for mechanical symptoms, osteotomy [removing a section of bone in the leg to change the load on the knee] or total knee replacement.

“This minimally-invasive surgical approach offers the advantage of restoring range of motion and reducing knee pain without interfering with possible future total joint replacement,” Mann said.

Clyburn, assistant professor of orthopedics at the university, said the uni-compartmental device may serve as a stopgap to total joint replacement.

The Young and the Restless

“The perfect candidate for this device is someone who is relatively young and has arthritis in only one compartment of their knee,” Clyburn said. “You can straighten the leg out, correct the deformity and stop the pain that the patient is having from bone rubbing on bone in that compartment.”

The surgery can be done as an outpatient or short-stay procedure. First, surgeons perform a knee arthroscopy, and then insert the device through an extended three-inch incision and fix it with bone cement.

Patients are encouraged to walk within two to three hours after surgery.

The recovery time is minimal, Mann said. Generally, patients do not need formal rehabilitation and can return to their normal activities within six weeks. Many are driving within two weeks. Running and jumping activities are discouraged, but participation in other sports is allowed.

Clyburn added that because only a third of the knee is replaced, patients generally report that it feels more natural.

The relief from the uni-compartment device, which is considered temporary, may last 10 to 12 years before arthritis spreads to other areas of the knee or the plastic in the device wears thin.

Uni-Knee “Life Altering”

Frost, now 69, had uni-compartmental devices in both knees more than a decade ago. “For me, it was life-altering. For about 10 years after the surgery, I really had no problems.”

Eventually, the osteoarthritis progressed in her right knee, and Clyburn had to do a total knee replacement. The left uni-knee is still doing well.

“The key here is to delay total knee replacement,” Clyburn said. “With a total knee replacement, the patient is in the hospital five or six days. They spend another 2-3 weeks on crutches, and it is 6-8 weeks before they are able to get around real well.”

He added that it’s easier on both patient and surgeon to replace a uni-compartmental device with a total knee than it is to do a total knee revision, which is a much more invasive procedure.

Repicci II, the uni-compartmental device used by Mann and Clyburn, has a good track record. In a recent study, 86 percent of patients had excellent to good results eight years after the surgery.

Last Updated: 6-16-2003