According to the Clinical Guidelines for Hip Osteoarthritis (OA) published in 2009, the prevalence of hip OA is between 0.4% and 27%. The most common complaint of individuals diagnosed with this debilitating disorder is hip and/or groin pain. Additionally, there is a concomitant decrease in the availability of ROM at the involved hip, which is typically in a capsular pattern (IR > ABD > Flexion). Knowing this information, what can we, as therapists, do for these patients?
The Clinical Guidelines determined that the use of manual therapy has ‘B’ Level Evidence to support its efficacy, which was actually the same level of support that flexibility, strength, and endurance exercises received. In 2005, Hoeksma et al performed a single-blind, RCT comparing the effect of manual therapy versus exercise in patients who were diagnosed with osteoarthritis of the hip based on the American College of Rheumatology’s clinical criteria. The manual therapy group received aggressive manual stretching of muscles determined to be tight, long-axis distraction of the involved hip, and traction manipulation in each limited position. Whereas the exercise group received a treatment protocol addressing diminished muscular strength, limited ROM, pain, walking ability, and were provided a HEP. At five weeks, the success rate of the manual therapy group was 81% for the primary outcome measure (6-point Likert scale ranging from “much worse” to “complete recovery”), while the exercise group only achieved a success rate of 50%. Additionally, change in the Harris Hip Score, walking speed, pain at rest, pain walking, mean a complaint, flexion-extension ROM, ER-IR ROM all favored the manual therapy group. Please take into consideration that the manual therapy group received NO exercise therapy and there were still substantial gains achieved, gains that exceeded those of the exercise group. Also, the effects of the manual therapy treatment lasted for 6 months, which shows the potential long-term benefit of these interventions.
In clinical practice, it almost always makes sense to combine these manual therapy techniques with therapeutic exercise interventions. Smith et al completed a case series looking at the outcomes of a combined manual therapy/exercise treatment approach to patients with OA of the hip. The primary author and his colleagues employed both thrust and non-thrust mobilizations of the hip depending on the findings of the evaluation and the degree of capsular restriction. All mobilizations/manipulations were performed in the direction of restriction followed by immediate reassessment of PROM and joint mobility to determine changes occurring after administration of the interventions. In addition to the manual techniques, individualized exercise programs were completed by the patients, which included a HEP. At the conclusion of treatment, all 7 patients included in the case series demonstrated substantial improvements and could no longer be classified as having osteoarthritis per the ACR’s clinical classification. The median improvement in total hip ROM was 82° (range, 70°-86°), the median improvement in pain on the Numeric Pain Rating Scale was 5 points (range, 2-7 points), and the median improvement in disability on the Harris Hip Score was 25 points (range, 15-38 points). Unfortunately, there was not a formal follow-up, thus long-term effects could not be determined. However, the primary author was able to contact 5 of the 7 patients who gave their subjective report of their symptoms. Patient 1 reported no change in symptoms since D/C, patients 5-7 reported not needing further treatment at 6 months, and patient 4 continued to seek intermittent treatment. So, this does bode well for the long-term effectiveness of the combination of manual therapy and exercise in the treatment of hip OA.
These techniques have been shown to be effective, but what do they actually do? According to a cadaveric study performed by Harding et al, accessory glide of the femoral head on the acetabulum in the anterior-posterior direction does occur and is dependent on force production. Increased force leads to a subsequent increase in the excursion of the femoral head. They found a mean displacement of 0.57 mm at 89N of force and 1.52 mm at 356N of force. An earlier study published by Arvidsson et al determined that it was necessary to apply a force of at least 400N in order to impart joint separation (0.8-3.0 mm) during the long-axis distraction technique. For comparison, 400N is equal to roughly 90 lbs or 41 kg of pressure. These studies show the ability of a physical therapist to provide forces significant enough to potentially stretch the tissues at and surrounding the hip joint, which should, in turn, cause a decrease in capsular restriction and an increase in ROM. An additional benefit of providing this manual care is the increase in force production demonstrated by studies published by Makofsky et al and Yerys et al. Both studies performed grade IV mobilizations which resulted in significant increases in peak torque of the hip abductors and gluteus maximus, respectively. The authors of these studies suggest that grade IV mobilization decreases the inhibitory input on the hip musculature. However, at this point, the mechanism behind these findings are purely speculative or theoretical.