There are substantial clinical implications in this proposed alteration of the osteoarthritis model (
Figure). In this revised model, osteoarthritis is not an inevitable disease of aging but the result of a definable history in the individual. Age-related changes do not lead to osteoarthritis by themselves. Rather, there must be some additional stress or insult to cause the condition. The greatest risk factor for osteoarthritis is not age but duration and intensity of stressing. Obviously, family members will have similar pain-related biochemical characteristics, similar susceptibilities to mechanical and histologic breakdown, and similar inflammatory and immunologic responses. Nevertheless, osteoarthritis—first and foremost—depends on the individual's own history.
Another implication is that joint restriction is causal rather than symptomatic, with restriction around the joint associated with early changes in the joint rather than late-stage degeneration.
Furthermore, the altered model implies a reversible arthrosis phase before the irreversible arthritis phase. The traditional model maintains that osteoarthritis cannot be prevented or arrested, let alone reversed. Yet recent in vivo research using hydropolymers as scaffolding for chondrocyte seeding and cartilage regeneration shows that, given some relief from compression and shear, chondrocyte activity may be recoverable.
41 This finding bodes well for joint rehabilitation in the absence of subchondral exposure, as well as for manual therapy aimed at improving capsular freedom.
Treatment intervention points are earlier. Preserving joint mobility offers the possibility of arresting further degradation, especially in earlier phases of osteoarthritis. Therefore, intervention points and goals of physical therapy are altered dramatically. As soon as maintenance pain relief is required in joint-related presentations, physical therapy should be introduced, combined with a program of effective stretching. Post-trauma and postsurgery rehabilitation needs to be immediate, comprehensive, and aimed at restoring articular freedom as well as limb function.
Finally, some therapeutic interventions used for patients with osteoarthritis need to be reconsidered. Many resistance and weight-loaded exercises (including outdoor walking, treadmill sessions, and exercycles) involve short-arc repetitive
motion, which tends to decrease joint mobility for the same reasons involved in repetitive occupational
42 and sporting activities.
43 Physical therapy has traditionally concentrated on countering muscle strength imbalance in the agonist muscles around an affected joint system
44 by strengthening weak muscles and lengthening strong muscles. However, there is evidence that such muscular imbalance can originate from disturbance of joint proprioception,
45 and it is likely that short-arc exercise programs cause shortening of muscle action and place further stress on the joint capsule and joint surfaces.
Although exercise of this type may improve congruency, such exercise is contraindicated in many cases, especially those cases involving joints that do not bear weight, such as the shoulder joint. Sustained static stretching of strong muscles, which also improves congruency, together with range-of-motion exercises are the preferred remedial choices for patients in these situations. Low-resistance loaded exercise would be the treatment of choice in early-stage hypermobile situations. For weight-bearing joints, low-resistance exercises such as aquaerobics, aquajogging, and swimming have a supportive role for patients who are obese, who have comorbid conditions, or who are elderly with sarcopenia.
46
Although there has been recent criticism of primary care physicians for neglecting weight-reduction and exercise programs
47 in managing osteoarthritis, most current exercise regimens tend to produce varied results for the previously mentioned reasons. In my experience, managing osteoarthritis in patients with comorbid obesity is a major clinical challenge that requires a carefully planned and multifaceted approach, even in early stages. While aerobic exercise is vital, the factors discussed in the present article need to be taken into account, often making tailoring of specific exercises necessary. The case for preventive management is therefore strong.
Strapping may palliate pain simply by restricting movement, but it does not alleviate contact pressure, and it introduces novel congruency patterns.
8 Lack of movement also promotes cartilage atrophy.
11 Strapping may retain a niche treatment role in hypermobile presentations, but its drawbacks limit its usefulness. In hypermobile presentations of osteoarthritis, as indicated by the Johnston County Osteoarthritis Project
22 and the Italian study by Stea et al,
24 contralateral transfer of stress must be considered, and bilateral evaluation should be routine. Restriction in 1 joint system, such as the hip, transfers stress to other joint systems that are functionally linked and more mobile, such as the knee, as noted in the Johnston County study.
22 The shoulder is similarly linked to grip, wrist, and forearm function. In addition, walking aids transfer stresses to other joint systems as the user assumes a flexed stance, producing additional problems in long-term use.
In the arthrosis phase of osteoarthritis, manual therapy should target joint range, congruency, and periarticular muscle coordination to reduce contact (ie, capsular) pressure and surface friction. After the arthritis phase has been reached, manual therapy becomes palliative at best. Although it is difficult to determine the cut-off point for effectiveness of conservative manual therapy in remedying the problem, a useful clinical measure is that improvements in range of motion do not last between treatment sessions, and overall improvement reaches a plateau. From that point on, delaying surgery produces higher ancillary costs and worse outcomes.
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