More recent literature: Abbott and colleagues concluded that manual therapy alone provided clinically and statistically significant benefits in pain and physical function over one year compared with usual care in participants with hip and/or knee OA.13 However, these authors found an antagonistic interaction between exercise and manual therapy—the combination of manual therapy and exercise therapy resulted in a smaller treatment effect than either manual therapy or exercise therapy alone.13 In a later study with a sample of individuals with knee OA, Abbott noted clinically important improvement in pain and function across one year when adding manual therapy with 12 sessions of supervised exercise therapy over nine weeks compared with the exercise therapy program alone.14
Fitzgerald and colleagues employed an intervention strategy very similar to the 2015 study by Abbott in a larger group of individuals with knee OA.15 They found a statistically significant benefit to manual therapy after nine weeks of exercise and manual therapy compared to exercise alone, but this benefit was no longer significant at one-year follow-up.15
A recent laboratory study investigated the effects of knee joint mobilization on deep-tissue hyperalgesia, vibration perception threshold and resting pain levels among individuals with knee OA.16 They found that knee joint mobilization resulted in increased pressure pain threshold along the medial joint line, improved vibration perception and reduced resting pain.16 However, these effects were measured only immediately following the application of manual therapy and do not provide information regarding the physiological pain-modulating effects of manual therapy over longer periods of time.
Overall, it appears that manual therapy provides at least short-term benefits in pain and physical function for individuals with knee OA. Although these effects may not be maintained over one year, manual therapy is likely a useful supplement to exercise therapy because it may provide the increased range of motion, accessory mobility, and pain relief necessary for a patient to properly perform the prescribed exercise program.
Sustaining Treatment Effects
Evidence supports the use of exercise therapy and perhaps the use of manual therapy to improve pain, function, and quality of life for individuals with knee OA. However, it appears that these benefits diminish over time.2,17 Strategies to sustain these positive effects are necessary to promote long-term maintenance of clinical improvements. Recent literature has focused on two ways to promote maintenance of benefits—periodically reinforcing exercise principles through face-to-face visits, and promoting independent management through physical activity promotion and lifestyle changes.
Booster sessions: The current delivery system for rehabilitation services may not adequately promote the maintenance of treatment benefits. Typically, supervised rehabilitation is provided over a short period of time (usually four to eight weeks), and then the patient is discharged to an independent home exercise program with no planned follow-up care with the rehabilitation provider. Booster sessions—periodic follow-up appointments occurring several weeks or months following the initial course of supervised therapy—have been suggested as a way to sustain treatment effects.7,17,18
