Less Pain, Better Function Achieved with PT for Knee OA vs Steroid Injection

Aching knees from osteoarthritis are a common complaint that is often treated with steroid injections, but a new randomized study from researchers at Brook Army Medical Center in San Antonio suggests that physical therapy may be a better option than glucocorticoid injections.

Patients who underwent physical therapy had a greater improvement in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores at 1 year, Gail D. Deyle, D.Sc., and colleagues reported in The New England Journal of Medicine.

The trial enrolled 156 patients —48% of whom were women, mean age 56— and evenly randomized them to PT or glucocorticoid injection. All patients were treated in primary care clinics in the U.S. Military Health System, although glucocorticoid injections were given by orthopedists or rheumatologists. “Patients received an injection in one or both knees of 1 ml of triamcinolone acetonide (40 mg per milliliter) and 7 ml of 1% lidocaine with the use of sterile technique,” Deyle and colleagues explained.

Patients were examined at 4 months and 9 months, and the patients received a mean of 2.6 injections over the 1 year trial.

PT included instructions and images to guide exercises and joint mobilizations. “During a typical clinical session, the physical therapist would implement hands-on, manual techniques immediately before the patient performed reinforcing exercises to help the patient perform the movements with little or no pain,” they wrote. “For example, if a patient could not fully extend or flex the knee, or those movements were painful, the physical therapist would use a hands-on, passive mobilizing technique to repeatedly move the knee to reduce stiffness while altering the mechanics of the technique to avoid pain. The patient would then perform repeated active knee movements in the same direction.”

Patients in the PT group attended a mean of 11.8 treatment sessions.

At baseline, the mean WOMAC scores were 108.8±47.1 in the glucocorticoid injection group and 107.1±42.4 in the PT arm.

“At 1 year, the mean scores were 55.8±53.8 and 37.0±30.7, respectively (mean between-group difference, 18.8 points; 95% confidence interval, 5.0-32.6), a finding favoring physical therapy,” they wrote. “In a prespecified analysis, 8 patients (10.3%) in the physical therapy group, as compared with 20 (25.6%) in the glucocorticoid injection group, did not have an improvement from baseline of at least 12% (the minimal clinically important difference) in the WOMAC score at 1 year.”

Seven patients in the PT arm also received a glucocorticoid injection and 14 patients in the injection group also had PT. Four patients in the glucocorticoid arm had surgery — three knee replacements and one arthroscopy.

In an editorial that accompanied the study, a pair of Australian researchers pointed out persons assigned to PT had a great deal more face time with clinicians than those who received injections, and that familiarity may have accentuated the placebo effect.

Kim L. Bennell, PhD, of the Centre for Health, Exercise, and Sports Medicine, Department of Physiotherapy, University of Melbourne, Melbourne, and David L. Hunter, PhD, of the Institute of Bone and Joint Research, Kolling Institute, University of Sydney, and the Rheumatology Department, Royal North Shore Hospital, Sydney also suggested that the trial was too brief to truly assess the benefit of injections.

“It could be argued that joint injections are used for their rapid, short-term effects before or contemporaneously with physical therapy because benefits with injections in the short term (6 weeks) have been shown to be greater than those with placebo. However, there was no evidence in the current trial to suggest that injections were more beneficial than physical therapy at 4 or 8 weeks. Another controlled trial also showed that a glucocorticoid injection administered 2 weeks before a course of exercise therapy provided no benefit with respect to reducing pain. If the population in the current trial had been restricted to patients with severe pain, the benefits with injection may have been greater, as was shown in a meta-analysis of individual patient data,” Bennell and Hunter wrote.

They noted that there were “fewer knee replacements in the physical therapy group than in the glucocorticoid injection group, although the total number was small — a finding that warrants further investigation. Finally, because the trial was conducted in a U.S. military population, the generalizability of the conclusions may be limited.”

1. In this small, randomized trial, physical therapy achieved greater improvement as measured by WOMAC score over the course of 1 year than glucocorticoid injections.

2. Be aware that the patients in the PT arm had more direct clinical contact with the provider, which may have accentuated a placebo effect.

Peggy Peck, Editor-in-Chief, BreakingMED™

Cat ID: 438

Topic ID: 437,438,438,737,192,48,158,68,925