Exercise for Patients with Osteoarthritis: A Phased Approach to Plannng

Nearly half of persons aged 65 and older have some form of arthritis. Osteoarthritis (OA)-the most prevalent form-is characterized by pain, stiffness, and loss of mobility that result from progressive deterioration of the articular cartilage that lines the joints. Although the cause is often unknown, OA has been associated with chronic joint instability, trauma, and overuse. There is no cure, but early diagnosis and treatment can minimize symptoms and help patients maintain active lives.

Initially, OA can make joint movement painful, and the patient's response may be to decrease joint motion. However, avoidance of activity can lead to increased disability that involves other joints and organ systems.

Keeping joints moving is an effective way to stabilize, if not slow, the degenerative process. This can be achieved through several forms of exercise, which numerous studies support as beneficial for patients with arthritis. In this article, we outline the points to consider when determining whether exercise is appropriate for your older patients with arthritis, the factors involved in implementing an exercise program, and a step-by-step plan for achieving success.

CONSEQUENCES OF DECREASED ACTIVITY

Articular cartilage serves 2 functions:

• It distributes joint loads over a wide area, thereby decreasing the stresses sustained by the contact surfaces.
• It allows opposing joint surfaces to move with minimal friction and wear.

The main cartilage cell, the chondrocyte, is surrounded by a matrix of collagen and a proteoglycan solution. Collagen gives cartilage high tensile stiffness and strength; the proteoglycan solution provides resistance to compressive forces.

Variation in total joint load during activities causes repetitive deformation of the cartilage matrix and exudation of the tissue's interstitial fluid. These processes, in turn, precipitate a sequence of events that disrupt the collagen-proteoglycan matrix and result in escape of proteoglycans from the cartilage. The loss of cartilage proteoglycans accelerates joint degradation and leads to arthritis. However, nutritional treatments (such as glucosamine and chondroitin sulfate) and exercise may be able to reverse this process.

Mature articular cartilage has no blood vessels and thus depends on diffusion for gas exchange and nourishment. Diffusion requires joint loading to force nutrient-rich synovial fluid through the cartilage matrix. Loaded healthy cartilage also appears to synthesize new proteoglycans; this enhances durability and protection.¹

To decrease joint motion in response to arthritis pain can diminish cartilage nutrition and protection and can also have harmful secondary effects. Although patients with OA often have comorbid conditions, such as diabetes and hypertension, the functional decline related to OA may itself result in additional disabilities. Decreased activity can lead to muscle atrophy, poor lipid profiles, compromised cardiovascular function and, consequently, increased susceptibility to disease and injury. Ultimately, patients may be unable to adequately perform activities of daily living and thus may become physically and psychologically dependent on others.

CONTRIBUTING FACTORS TO DYSFUNCTION AND IMPAIRMENT

In older persons, muscle dysfunction, proprioceptive deficits, and associated mobility impairment increase the risk of falls, fractures, and functional dependency. Several physiologic factors that are associated with aging can contribute to these problems:

• An increase in total body fat that usually results in increased body weight and decreased lean body mass.
• Reduced bulk, strength, and endurance of type 2 (fast-twitch) muscle fibers.²
• Decreased muscle contractility and increased susceptibility to fatigue.³

Joint instability is common in older persons with OA. Several studies have demonstrated an association between joint pain and periarticular muscle weakness.⁴ These both appear to be part of a cyclic process that, in an overly simplified model, begins with articular damage. This damage results in pain and effusion, which diminish with rest. However, the muscle weakness that can follow decreased activity compromises neuromuscular protective mechanisms. This may lead to excessive joint movement, instability, traumatic loading of the joint, and further damage-which results in more pain and thus perpetuates the cycle.

The relationship between muscle weakness, joint damage, and disability is complex. There is little correlation between radiographic signs of joint damage and the pain and disability experienced by patients with OA.⁵ Muscle weakness, on the other hand, is an early symptom frequently reported by patients⁶ and is a better determinant of pain and disability than radiographic changes.

In addition to motor deficits, patients with joint damage also have deficits in the sensory function of muscle. Because proprioceptive acuity decreases with age,⁷ joint damage,⁸ and muscle fatigue, arthritis may be propagated-if not initiated-by muscle dysfunction.

IMPROVING MUSCLE FUNCTION

Physical activity can reverse to some degree the atrophy caused by periods of inactivity. The extent of progress is determined primarily by the degree of the patient's motivation to initiate and maintain the activity. Muscle function can be improved even in very old persons.⁹

Proprioception can also be enhanced in arthritic joints. In a study of the effects of exercise training during 30 days of bed rest, proprioception improved in patients who exercised and remained unchanged in those who did not.¹⁰

Temporary or permanent use of orthoses can also enhance proprioceptive accuracy. One study demonstrated that use of a knee brace was associated with an 11% improvement in tracking ability.¹¹ Use of an elastic bandage also appears to improve proprioception in osteoarthritic knees. It is theorized that the movement of the bandage stimulates the superficial skin receptors, nerve endings, hair end organs, and tactile menisci; this additional neural input is most likely combined with information from muscle receptors to aid the patient in coordinating movements.

EFFECTS OF EXERCISE ON PREEXISTING OA

The connection between exercise and OA is controversial. Several studies of former athletes have even implicated their sport as the cause of their arthritis. A 2- to 4-fold increased risk of OA at the hip and knee has been described in former elite athletes.¹² Other studies have found the incidence of degenerative joint changes in athletes to be similar to that seen in the general population.¹³

In spite of the radiographic changes, older athletes in most studies appeared to have fewer symptoms and disabilities than sedentary persons. However, it is difficult to conclude that lifelong athletic activities do not cause increased wear on joints. Many sports (eg, soccer, football, running, tennis) involve a great amount of high-impact stress. The demands of training and actual competition increase the likelihood of trauma and ensuing arthritis.

The critical question is whether mild to moderate exercise exacerbates preexisting arthritic conditions. The literature on this issue is sparse. Active persons with arthritic conditions often select exercises that have a low impact on their affected joints and moderate the duration of their workouts to maximize gains and minimize discomfort. This approach results in routines that accomplish targeted goals and do not cause reinjury.

If activity or motion of any kind aggravates joint pain, an external brace or joint replacement may be warranted. Following or preceding either intervention, some form of rehabilitative exercise is often advisable to optimize results.

HOW TO BEGIN

To successfully implement an exercise program for a patient with OA, select convenient, safe, and enjoyable activities and set achievable goals. Implement the plan in phases, and progress gradually from one phase to the next; this will help both you and your patient anticipate difficulties and gauge progress.

It is not practical to try to develop a program that fits all patients. Numerous physical, financial, and motivational parameters influence each patient's ability to set goals and maintain them. Although some patients need only initial guidance from a therapist, others require constant supervision. For financial or social reasons, a group approach may be best for some patients.

The following program is designed for older persons with OA who have comorbid conditions or a sedentary lifestyle. However, because everyone can benefit from exercise, this information may be useful for other persons who have symptoms of OA or who are interested in a preventive routine. The following is a step-by-step approach to tailoring the plan to individual needs.

Phase 1: The initial evaluation. The first step, the initial evaluation, is often the most difficult. Given the scope and depth of the history taking and physical examination that are required, it is advisable to make your initial evaluation the focus of an entire office visit, rather than try to incorporate it into a routine health evaluation. The objectives of the initial evaluation are to gather objective and subjective baseline data, decide which area of the body to focus on first, and identify potential contraindications to activities.

Gathering baseline data. Include most of the routine aspects of the physical examination (such as height, weight, and vital signs), but focus on functional muscle strength, such as the ability to rise from a chair or climb stairs. Also examine joint angles and such neurologic faculties as proprioception and balance. The information gleaned may serve more than one purpose; it may lead to the discovery of a previously undiagnosed condition. It also provides a baseline that can be used to show patients they are making progress, thus enhancing compliance.

Targeting an area. Often, the patient can clearly identify the most painful or disabling joint, which is the best one to begin with. In your physical examination, also evaluate joints distal and proximal to the target joint. (So that the patient knows you are not ignoring his or her responses, be sure to explain that you are doing this because few joints function independently.) While working on muscles to improve knee function, for example, it is often useful to include hip exercises. Similarly, a patient with OA of the hip may benefit from upper extremity exercises that help him use his arms to get out of a chair.

Also examine the other joints. A patient with painful OA often compensates by using the contralateral joint or unusual biomechanics. This can result in accelerated degeneration in a previously asymptomatic area.

Identifying contraindications. Very few conditions absolutely preclude any form of exercise. Activities can be modified to minimize cardiovascular burdens or avoid unnecessary joint stress. When identifying potential contraindications, consider carefully the patient's mental and physical health.

Obtain an initial radiograph of the target joint to rule out other potential joint and bone pathology and to confirm the diagnosis of OA. Examine the patient for signs of neurologic impairment that can result from chronic disease, such as diabetes; from vitamin deficiency; or from thyroid disorders. A patient who has avoided the physician's office for years and then presents with worsening joint pain may have an underlying systemic condition that prevents him from exercising.

Special circumstances. For an obese patient, focus the exercise program on functional activities and avoid unnecessarily high impact on joints. In addition, encourage the patient to adopt some form of dietary modification. Overweight patients-and also persons who have severe mental disorders-may benefit from group activities, especially if these include their peers and involve dietary counseling.

Follow-up. Because symptoms may develop that are not directly attributable to physical activity, follow-up to an exercise program is crucial. Tell patients that delayed-onset muscle soreness following unaccustomed or vigorous exercise is common. It is especially marked following the initiation or resumption of exercise after a period without training. Typically, delayed-onset muscle soreness begins a number of hours after exercise and is quite prominent on the first 2 days after activity. This pain should be distinguished from discomfort that occurs during exercise; the latter type of discomfort is often associated with muscle fatigue or joint damage.

A physical therapist or certified athletic trainer can monitor a patient's progress against an initial baseline musculoskeletal assessment. However, seeing a physical therapist or athletic trainer may not be practical or possible; independent activity may have to suffice. Exercise can be performed without extensive supervision. Often, combining exercise with pleasurable activities or hobbies is an excellent way to improve the function of arthritic joints.

Positive reinforcement is essential; bimonthly visits are recommended if the patient is not seeing a physical therapist. The focus of these visits is to assess symptom improvement or exacerbation.

Phase 2: Range of motion exercises. Because many patients who have OA have moved the affected joint only minimally (because of pain), any exercise program should begin with stretching (Figure 1). Stretching improves range of motion. Have the patient perform the exercises slowly and cautiously. Although an activity may be awkward for the patient initially, it should be painless.¹⁴

Heat helps relax muscles and decrease the pain of stretching activities. Suggest that patients apply moist heat to their target area for 10 to 15 minutes before stretching.

Advise patients to report symptoms of dizziness, lightheadedness, numbness or tingling, or persistent discomfort. If any of these occur, the exercises that produce the side effect may be modified or excluded from the routine. Have patients who are not working with a therapist recruit an exercise partner or supervisor to ensure that they do not incur injury during their workouts. This person can be a nurse, spouse, relative, or friend.

To get the patient into the habit of stretching, have him do stretches daily for approximately 1 week before he adds other activities to the exercise program. If a therapist is involved, light exercises may follow these stretches. Allow patients who are exercising independently to add a strengthening component to the exercise program only after they have done stretches for 1 week. This ensures that the patient will not become overwhelmed and enables you to get feedback on how he is doing. Address any problems that developed during stretching before the patient progresses to the next phase.

Phase 3: Isometric strengthening exercises. Muscles that have been ignored for a long time need strengthening (Figure 2). Warn patients to expect some mild achiness; however, signs of joint swelling and stiffness are red flags that mandate discontinuation or modification of the exercise.

The first strengthening exercises-isometric exercises-are associated with the least amount of stress to joints and do not cause joint or muscle inflammation.¹⁵ Isometric contractions do not cause muscle fibers to lengthen or shorten, and they do not put joints through ranges of motion. Encourage patients to do these strengthening exercises every other day initially. Have them continue to perform stretching exercises daily.

Phase 4: Isotonic strengthening exercises. After 1 to 2 weeks of isometric exercises, patients are ready for isotonic exercises. Although these exercises may replace the previous isometrics, the stretching routine should continue throughout the program.

When a muscle undergoes an isotonic contraction, the muscle fibers either lengthen (eccentric contraction) or shorten (concentric contraction). The adjacent joint is put through the full range of motion.

If a patient is motivated to work out more frequently than every other day, encourage him to do so, but with caution, because excessive activity can cause overuse injuries. To avoid such injuries, insist that the patient set aside at least 2 days every week for rest and recuperation. Performing the exercises in water provides both good resistance and buoyancy that can minimize joint stresses. Have the patient continue to do stretches as often as possible.

Phase 5: Recreational or functional exercises. When the patient can stretch and do isotonic exercises with relative ease, he is ready for functional or recreational exercises. As he moves into this phase of the program, encourage him to continue his stretching and strength training. The beneficial effects of strength training decline over time and disappear if they are not maintained.¹⁶

Appropriate activities include swimming, walking, table tennis, low-impact aerobics, dancing, and bicycle riding. Advise patients to avoid high-impact activities, such as running, high-impact aerobics, and contact sports.

A former athlete may insist on participating in an activity that could be stressful to his joints. Discuss the deleterious consequences of too frequent participation and, if necessary, fit the patient with a protective brace.

Use of exercise equipment has the advantage of providing both a measurable performance baseline and objective feedback on progress. If appropriate guidance and supervision are not available, however, use of equipment can do more harm than good. The exercise program proposed here is simple and safe enough that it can be performed independently without equipment.

FOR MORE INFORMATION:

Daly MP, Berman BM. Rehabilitation of theelderly patient with arthritis. Clin Geriatr Med. 1993;9:783-801. This article includes a discussion ofrheumatoid arthritis and osteoarthritis. Joint injections,modalities, and complementary medicineare mentioned.

Deyle GD, Henderson NE, Matekel RL, et al.Effectiveness of manual physical therapy and exercisein osteoarthritis of the knee. Ann Intern Med.2000;132:173-181. This article focuses on the effectivenessof exercise.

Hurley MV. The role of muscle weakness inthe pathogenesis of osteoarthritis. Rheum Dis ClinNorth Am. 1999;25:283-298. This excellent articlesummarizes many of the previous studies andfindings.

References:

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