OSTEOARTHRITIS OF THE TRAPEZIAL JOINT Trapeziometacarpal (TM) joint with osteoarthritis (OA) has a specific classification based on radiographic findings. These findings are as follows: Stage I: painful synovitis (inflammation of the synovial membrane) with effusion and hypermobility. Stage II: radiographs show classical OA changes of joint space narrowing, osteophytes or joint debris less than 2 mm in diameter. Often there is less mobility and only minimal crepitus. Stage III: advanced OA with marked crepitus but without scaphotrapezial (ST) joint disease. Stage IV: advanced OA of the TM joint with radiographic OA changes in the ST joint. OA most commonly affects the two distal joints of the fingers and thumb CMC joints. The thumb CMC joints tend to be the most symptomatic. However, osteophytes can occur at the MP joint where they can cause triggering of the flexor tendons. Osteophytes can also be found at the wrist and intercarpal joints which can limit motion and cause pain. Men and women have the same distribution of osteoarthritis, however women have more severe symptoms. One contributing factor to a painful thumb joint is generalized ligamentous laxity with consequential joint hypermobility. Recent studies document hypermobility, especially in the thumb CMC joint, which may result in a variety of overuse lesions and osteoarthritis. In the patient with moderate symptoms of osteoarthritis, asking them to point where they are having pain will often reveal them pointing to the base of the thumb. In addition, upon visual inspection of the CMC joint, a squaring (or a shoulder) can be observed at the base of the thumb. If this is noted, a further physical examination is usually not indicated secondary to prolonged pain and swelling. If no visual anomaly is noted, a grind test of the CMC joint can be performed. This test is done by palpation over the CMC joint while compressing and rotating the 1st metacarpal in the CMC joint. Distraction of the joint at the end of the grind test is also performed to demonstrate capsular tenderness. In addition, a Finkelstein’s test is also indicated for localizing the pain in the first dorsal tendon compartment and for identifying de Quervain’s tenosynovitis. The first line of treatment, once a diagnosis of trapeziometacarpal OA is confirmed, is the utilization of a custom fabricated thumb spica splint. Depending of the severity of symptoms, the splint may consist of a thumb MCP/CMC stabilization or a CMC stabilization only. However, it is important to be aware that the MCP joint is subject to greater forces when not splinted, secondary to the restriction at the CMC joint. Consequently, non stabilization of the MCP joint requires a healthy MCP joint. Many thumbs that exhibit CMC OA also have MCP issues such as hyperextension. Effective splinting for CMC arthritis may reduce the need for surgery. However, for active adults who wear a stabilization splint, nonadherence to splint usage is evident. This is secondary to the splint being too restricted, especially for writing, knitting and sports. It should also be noted that many individuals with CMC osteoarthritis have poor thumb mechanics and muscle imbalance which put this joint in a poor position and can www.eorthopod.com/…/hand_cmc_anat02.jpg www.eorthopod.com/ public/patient_education/65 www.drruns.com
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