Effectiveness and cost-effectivness of physical therapy for knee osteoarthritis

Osteoarthritis, sometimes called degenerative joint disease, is a slowly progressive disease in which joint cartilage breaks down. Normally, cartilage on the ends of bones allows smooth, pain-free joint movements. In OA, cartilage becomes thin and irregular, resulting in symptoms of joint pain and stiffness. Grinding or cracking sensations may occur. Joints that are under high stress due to repeated activity or weight bearing are most susceptible to OA. The hips, knees, hands and spine are commonly affected. OA becomes more common with aging.

Common pharmacologic treatments for OA include nonsteroidal anti-inflammatory drugs (called NSAIDs) and analgesics (e.g., acetaminophen and ibuprofen), and exercise is considered an excellent first line, conservative, treatment for the disease. Researchers recently compared the cost-effectiveness of four different physical therapy strategies among 300 people with knee OA participating in a two-year study across several different institutions.

Strategy one included 12 visits of exercise therapy alone over a nine-week period; strategy two included eight initial visits of exercise therapy within a nine-week period plus four booster sessions at 3 time points (two boosters at month five and one at months eight and 11) spaced across a 12-month period; strategy three included 12 visits of exercise therapy plus manual therapy; and strategy four included eight initial visits of exercise therapy plus manual therapy and four booster sessions. Total health care costs were estimated using patient-reported outcomes as well as data from the Healthcare Utilization Project and the Medicare physician fee schedule.

"We believed there was a need to improve both the magnitude and sustainability of treatment effects of exercise therapy for improving pain and function in people with knee OA," explains G. Kelley Fitzgerald, PT, PhD, FAPTA; professor and associate dean of graduate studies, University of Pittsburgh School of Health and Rehabilitation Sciences and the principal investigator in the study.

"Previous research indicated that using manual therapy might be a way of improving the magnitude of treatment effects, and booster sessions might be a way of ensuring sustainability of treatment effects. We also believed it would be important to determine the impact on health care costs to inform best-practice approaches with regard to using manual therapy and/or booster sessions, should they prove to be clinically effective."

The researchers noted that the booster strategies (strategies two and four) significantly lowered health care costs and showed greater effectiveness in the treatment of knee OA. Between those two strategies, strategy two cost $1,061 more, but gained .082 more quality-adjusted life years, which looks at the burden of the disease in comparison with the quality and quantity of life.

Overall, the study showed that, while exercise therapy remains effective in treating people with knee OA, it might be more effective to supplement exercise with manual therapy and space physical therapy visits over a longer period of time to maximize long-term benefits.

"These results indicate that supplementing exercise with manual therapy and spacing physical therapy sessions across a longer period of time may provide greater benefit to individuals with knee osteoarthritis, while simultaneously reducing downstream health care utilization," explains lead investigator in the study, Allyn Bove, PT, DPT; assistant professor, Department of Physical Therapy, University of Pittsburgh School of Health and Rehabilitation Sciences.

Based on these findings, Dr. Bove believes patients should consider consulting a physical therapist to treat the pain and disability caused by knee OA and notes they should be willing to potentially commit to re-visiting their physical therapist every few months to reinforce the benefits. Additionally, Dr. Bove says these findings may encourage physical therapists to add more manual therapy techniques, as well as booster sessions to their plans of care for these patients.