Weight loss—The AAOS recommends self-management, exercise, and integrated health care programs for patients with knee OA.
9 Examples of these types of programs are listed in
Figure 1. Of these, a trial of weight loss with diet and exercise received the highest possible AAOS recommendation for nonoperative management of knee OA.
9
The Framingham knee osteoarthritis study
10 showed a greater than 50% reduction in primary knee OA with a decrease in body mass index of 2 or more. To put this into perspective, the force on each knee per step is equivalent to approximately 2 to 3 times a person's body weight. Therefore, an additional 33 lb of body weight could add up to 100 lb of force on each knee per step. Assuming the average person takes roughly 2000 steps per day, this additional force could equal up to 100 extra tons of force on each knee per day. Thus, 33 lb of weight loss can have a dramatic effect on the amount of load bearing to the knee.
Aerobic exercise—According to a meta-analysis by Brosseau et al,
11 randomized controlled trials have shown that aerobic exercise contributes to better long-term function in active patients with primary knee OA. Home exercise programs and supervised exercise classes can substantially decrease pain and improve function in patients with knee OA.
11 Strengthening specific muscles such as the tensor fascia lata improves knee biomechanics. However, many patients have a tough time dedicating themselves to home exercise programs. In addition, if aerobic exercise and muscle strengthening regimens are not maintained, the benefits can be lost after 6 months.
12 Physicians should encourage exercise and weight loss during the initial office visit with patients who have early knee OA.
Orthotics—Because of a lack of concrete evidence, many physicians question the use of bracing and other orthotics for symptomatic relief and treatment of knee OA.
9 However, a clinical trial by Brouwer et al
13 has shown some benefit with the use of knee bracing to unload the diseased knee compartment affected by OA. Many patients with OA may have only 1 affected compartment of the knee, including patients with a history of trauma, patients who used to be athletes, and patients who have had a partial or complete meniscectomy. Knee braces can be designed to off-load the affected compartment in patients with monarthritis of the knee, especially those who wish to delay undergoing a surgical procedure. Indication includes a passively correctable, unicompartmental varus or valgus disease in which the angle of the deformity is less than 10°.
12 According to a review by Krohn,
14 clinical and gait laboratory analyses also suggest that lateral wedge orthoses can play a role in the treatment of persons with medial compartment knee OA. Functional improvement with lateral wedges is thought to reduce the external varus thrust and thus medial compartment load during ambulation.
14 The prescription and use of these treatments should be specific to the patient and tailored to the patient's individual needs.
Osteopathic manipulative treatment—Osteopathic manipulative treatment and physical therapy can be an essential component of nonoperative care. A full appreciation of the somatic, sympathetic, and lymphatic systems and their integrated parts is essential for understanding the etiologic process and management of knee pain and inflammation. Part of the pathophysiology of the arthritic knee is related to changes in the autonomic nervous system, blood and lymph flow, fascial tension, limitations in range of motion, and relationships of the length and tension of the muscles around the knee.
15,16 Oftentimes, a combination of these factors is contributing to the pain, inflammation, and impaired function of the knee. Therefore, to effectively manage arthritic knee pain, one must perform a thorough evaluation of the surrounding muscle strength, flexibility, tone, skin topography, range of motion, and soft tissues.
Restrictions in soft tissues and motion about the knee can have important consequences on the functioning of the joint.
15,16 Nutrition is brought to the cartilage via diffusion of synovial fluid.
17 Appropriate diffusion is related to unrestricted blood and lymph flow and maintenance of motion and slight compression through the joint.
18 Unfortunately, as motion decreases, the integrity of the cartilage also decreases because of impairment of nutrients entering and metabolites exiting the joint.
16,18 As a consequence, attention must be placed on maintaining joint mobility and addressing imbalances in the quadriceps, hamstrings, and gastroc-soleus muscles. Other imbalances in the somatic system can include myofascial somatic dysfunction, which can impede motion, functions, and lymphatic flow around the knee joint.
16,18 In this instance, attention should be focused on normalizing myofascial and lymphatic restrictions through techniques such as counterstrain positioning, lymphatic pump, trigger point injections, soft-tissue massage, and myofascial release.
15,17,19
Maintaining an ideal body weight, body mass index, and posture significantly decreases the joint reaction forces across the joint.
11,19 Impaired posture and malalignment of lumbar spine and lower extremity can change the body's overall mechanical alignment and contribute to knee pain. In addition, changes in the alignment of the lower extremity can place excess stress in a particular compartment of the knee and exacerbate cartilage damage.
3 These abnormal changes in posture and alignment also facilitate increased sympathetic flow to the limb.
15,17,19 Increases in sympathetic activity can further irritate pain receptors, thus increasing one's sensitivity to pain. Treatment can be focused on normalizing the sympathetic system with techniques such as rib-raising and soft tissue massage.
17,19
In summary, addressing particular somatic and sympathetic dysfunctions; maintaining ideal body weight; correcting posture, muscle, and alignment imbalances; improving myofascial tone; and normalizing blood and lymph flow should be goals in the treatment of patients with arthritic knee pain.