Symptomatic knee involvement is estimated to affect as much as 10% of the population older than the age of 65 years. Obesity is a major risk factor. OA of the knee produces pain that is localized to the medial and/or lateral joint line and worsened by prolonged weight bearing and stair climbing. In later stages, crepitus is often marked and range of motion reduced. A very small effusion may be noted. The joint appears to be enlarged and feels bony. Patellofemoral joint involvement produces anterior knee pain that is exacerbated by going down stairs. On occasion, very few physical findings may be noted, although pain and radiographic changes are prominent. A skyline view of the flexed knee can reveal patellofemoral disease.

Degenerative hip disease arises in young patients with congenital dislocations or slipped femoral capital epiphyses. In the elderly, it results from wear and tear. A unilateral or asymmetric distribution is typical. The patient may describe pain that is deep in the hip and radiates into the anterior medial thigh, groin, buttock, or medial knee. The site of radiation (e.g., groin or buttock) may be the only area of reported pain. At first, pain occurs only on prolonged standing or walking, but as OA progresses, discomfort may become continuous and especially unbearable at night. The ability to engage in sexual intercourse is sometimes compromised. Loss of internal rotation during flexion is the earliest change and is as reliable as radiographic findings for diagnosis. The result of Trendelenburg test (see Chapter 151) is positive.

Characteristic sites include the DIP joints and base of the thumb (first carpometacarpal joint); sometimes, proximal interphalangeal (PIP) joint involvement is noted. Hand disease is most common in middle-aged and elderly women, many of whom have a strongly positive family history. In some, a low-grade inflammatory response may accompany early, rapid, mucinous degenerative changes, so that the joints take on a tender, cystic inflammatory appearance. Later, osteophytes form, giving rise to characteristic bony protuberances in the DIP joints (Heberden nodes) and occasionally PIP deformities (Bouchard nodes) that superficially resemble those of rheumatoid disease. Eventually, all inflammatory activity resolves, and the joints are left nontender with some limitation of motion.

The base of the thumb, a site of much physical stress, is vulnerable to degenerative change. Pain develops in the region of the thenar eminence and particularly over the carpometacarpal joint. Because the thumb is so important to manual dexterity, the development of arthritis at this site may be disabling. Grip becomes impaired, and fine movements of apposition are restricted. Osteophytes are palpable and, in rare instances, may encroach on the flexor tendon sheath, causing tenosynovitis.

Degenerative changes commonly involve the posterior diarthrodial joints of the lower cervical spine (see Chapter 148). Although radiographic changes are frequent, most persons are asymptomatic. Moreover, the correlation between symptoms and radiographic findings is often poor. The patient may have pain and stiffness in the neck, but sometimes, pain is reported only in the occiput, shoulder, arm, or hand. In a few instances, scapular or upper anterior chest pain is produced. Osteophytes can protrude into the foramina and impinge on nerve roots (most often C6 and C7), causing radicular pain that radiates to the shoulder, upper arms, hands, or fingers (see Chapter 167). At night, the patient may awaken with paresthesias and numbness in the arms that can be alleviated by getting up and shaking the arms. On examination, neck motion is restricted to some extent in all directions, especially lateral flexion and extension; movement reproduces or aggravates symptoms. Reactive muscle spasm and tenderness are often present, and decreased sensation, weakness, and diminished reflexes occur when root compression is marked. However, even when symptoms of root compression are reported, neurologic findings may be scant, and their absence does not rule out the complication.

Degenerative changes in the lumbosacral spine involve the intervertebral disks and the apophyseal joints. With aging, the disk nucleus becomes brittle and less elastic. Herniation posteriorly or laterally through a defect in the disk annulus may occur. Intervertebral spaces narrow, and marginal osteophytes form. The apophyseal joints show typical secondary degenerative changes. Disk or osteophyte encroachment on the foramina can lead to nerve root compression. The L4, L5, and S1 roots are most commonly affected. The patient reports pain across the lower back with radiation into the buttock and posterior thigh or down into the lower leg if root compression has occurred. Forward flexion and extension are reduced, but lateral flexion is painless. Focal areas of tenderness are common and often caused by spasm of the paraspinous musculature. Disk or osteophyte encroachment into the spinal canal can lead to spinal stenosis, which affects the cauda equina and exiting nerve roots. Compression of nerve roots produces pseudoclaudication (pain in the buttocks or thighs during prolonged standing or walking that is relieved by sitting or bending). On examination, thigh symptoms may be brought on by 30 seconds of lumbar extension and then relieved by having the patient bend forward. In addition, the patient may have a wide-based gait and neurologic deficits in the lower extremities.

OA may involve the great toe at the metatarsophalangeal joint to cause bony enlargement and a valgus deformity. Crepitus and pain in the temporomandibular joint are sometimes seen secondary to bruxism (grinding of the teeth because of anxiety or anger). Pain is reproduced by opening the mouth widely. Because OA is not a systemic disease, no extra-articular manifestations and no serum abnormalities occur; the sedimentation rate is normal, as is the synovial fluid in early disease. Radiographic findings are limited to the joints and include irregular narrowing of the joint space, sclerosis of subchondral bone, bony cysts, marginal osteophytes, and buttressing of adjacent bone.

Pain relief is a top priority for most patients. Analgesics remain the predominant pharmacologic approach in the absence of disease-modifying therapy for OA. The basic approach to analgesic use in OA follows the standard paradigm of best practice for chronic nonmalignant pain (see Chapter 236). Because an individual patient’s response to analgesics is unpredictable, it may require some degree of a trial-and-error approach. Intermittent use of analgesics sometimes suffices, but continuous therapy is often needed in the absence of more definitive treatment. Whether to use a pure analgesic agent or a nonsteroidal anti-inflammatory drug (NSAID) with analgesic properties is a subject of debate. Of interest, there are few long-term study data on the efficacy of analgesic therapy, even though these drugs are often taken chronically. Chronic use has raised concerns about adverse effects, both for pure analgesics and for nonsteroidals taken for OA.

OA patients with unrecognized and untreated depression benefit from disease-specific treatment, be it pharmacologic and/or interpersonal. Pain control improves, as does functional state and overall quality of life. Starting a generic formulation of a selective serotonin reuptake inhibitor (SSRI) antidepressant (e.g., fluoxetine; see Chapter 227) to supplement the analgesic program can be particularly helpful in depressed OA patients, although it may take several weeks for benefits to be fully realized. Use of selective norepinephrine/serotonin reuptake inhibitors (SNRIs) (e.g., duloxetine) is under study.

Of the nonpharmacologic therapies, exercise/physical therapy and weight reduction show the most consistently beneficial results for patients with OA, especially in those who are overweight or obese and have disease of the major weight-bearing joints.