Neuropathies augment the clinical problems of degenerative disease of the spine. Spurs growing from vertebral margins adjacent to degenerated discs and from facet borders may narrow the foramina through which the spinal nerves exit. Pressure on and irritation of the nerve roots causes neuralgia, paresthesias, or paresis. Neuralgic pain in the occipital region and about the shoulders and arms may result from spurs in the cervical region; sciatic pain is caused by nerve root pressure from a protruding degenerated disc or spurs in the lumbar region. In the cervical spine, compression of the spinal cord from large osteophytes or from displaced degenerated discs may lead to serious neurologic complications manifested by upper motor neuron or long tract signs. The same type of spinal cord compression may result in spinal stenosis in the lumbar spine, leading to claudication and lower limb weakness.

LABORATORY STUDIES

Hematocrits, blood cell counts, ESR, and results of serum protein electrophoresis, blood chemistry studies, urinalysis, and other laboratory tests are usually normal unless other diseases exist. If severe degenerative changes cause a secondary (traumatic) synovitis, the ESR may be slightly elevated. Serum rheumatoid factor may be positive, not as a result of osteoarthritis but due to elevations observed with aging or other disease states that may coexist with osteoarthritis. Synovial fluid analysis of involved peripheral joints reveals limited abnormalities with a slight increase in synovial fluid white blood cell count, usually less than 2000/µL. Radiographs reveal characteristic diagnostic findings: cartilage thinning, osteophytes (spurs and bony bridging), and bone cysts.

DIAGNOSIS

Diagnosing osteoarthritis and differentiating it from rheumatoid arthritis are usually not difficult. The localization of pathology to one or a few weight-bearing joints of the lower limbs, the spine, the distal and proximal interphalangeal finger joints, and/or first carpometacarpal joints in otherwise healthy older persons, together with normal results of laboratory studies and characteristic radiographs, confirms the diagnosis. However, the abnormalities seen in radiographs of the spine often do not parallel the clinical findings: extensive and severe pathologic changes may be seen in radiographs when the patient has only mild pain and disability. On the other hand, only minor osteophytic or degenerative changes seen in conventional radiographs of the spine may be accompanied by severe arthritic symptoms if the abnormalities are in a critical area. MRI is extremely helpful in delineating details of vertebral and disc alterations occurring in patients with spine involvement and allowing correlations with clinical symptomology. Similarly, MRI is helpful in delineating osteoarthritic changes related to osteoarthritis of the knee or hip joints (see Plates 5-24 and 5-26).