Today's News

Wednesday, March 15, 2000

Multiple techniques to alleviate osteoarthritis

There are multiple nonoperative techniques a surgeon can use to alleviate the pain of an osteoarthritic joint, including oral medications, physical therapy, injections and off-loading knee braces. Scientific exhibit 16 presents a study to analyze subjects under in vivo dynamic conditions, using fluoroscopy to determine if off-loading knee braces actually separate the femoral condyle from the tibial plateau during the mid-stance and heel-strike phases of gait.

The study demonstrates in vivo that articular separation of degenerative knee compartments can be achieved with offloading braces with subsequent subjective relief of knee pain. However, the researchers said these braces may have limited effectiveness in obese patients.

Forty subjects with substantial unicompartmental osteoarthritis were studied under fluoroscopic surveillance in the frontal plane while performing normal gait on a treadmill. The subjects were patients of one surgeon and were all clinically diagnosed to have marked unicompartimental degenerative joint space narrowing. Initially, each subject was asked to perform normal gait on a treadmill under fluoroscopic surveillance in the frontal plane. An offloading osteoarthritic knee brace was then fixated on the osteoarthritic knee joint. The subjects were then asked to walk on level ground while wearing the brace to rate the effectiveness of the brace in alleviating pain. The subjects were then asked to perform normal gait on a treadmill while wearing the brace. Successive fluoroscopic images of each patient at mid-stance and heel-strike (with and without a brace) were downloaded to a work station computer. The captured fluoroscopic images were then analyzed using digitization.

Thirty-four of 40 subjects (85 percent) judged the osteoarthritic knee brace effective in reducing knee pain. Six of the subjects (15 percent) were not able to detect a change in knee pain. All of these subjects were overweight, resulting in suboptimal brace fixation. Thirty-one of 40 subjects (78 percent) demonstrated articular separation of the degenerative knee compartment at heel-strike and 28 of 40 subjects (70 percent) at mid-stance. Thirty-one of 40 subjects (78 percent) experienced an angular change at heel-strike, while 37 of 40 subjects experienced an angular change at mid-stance. The average amount of change in condylar separation was 1.7 mm (0.06.4) at heel-strike and 1.9 mm (0.0 - 7.9) at mid-stance. The average amount of change in angle 0, was 2.0 degrees (0.0 - 4.8 degrees) at heel-strike and 1.6 degrees (0.0 - 5.1) at mid-stance.

The researchers, from the Rocky Mountain Musculoskeletal Research Laboratory, Golden, Colo., are Richard D. Komistek, PhD, president and executive director; Douglas A. Dennis, MD, chairman and medical director; and Eric J. Northcut, MS, manager, engineering. Also, Jorge A. Ochoa, PhD, Johnson & Johnson; and Curt D. Hammill, graduate student, Colorado School of Mines, Golden, Colo.

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Last modified 22/February/2000 by IS