Thumb carpometacarpal joint is the most common upper extremity arthritis requiring surgical reconstruction. Varying clinical pictures from occasional pain to disabling instability make identifying and treating this disease both challenging and gratifying. Nonoperative interventions such as activity modifications, occupational therapy, and splinting can be effective but surgical treatment remains the standard for end stage arthritis. Various surgical options such as arthroscopy, osteotomy, fusion, and arthroplasty are all discussed in this chapter.
EPIDEMIOLOGYThumb carpometacarpal (CMC) joint is the most common upper extremity arthritis requiring surgical reconstruction. 1 Overall prevalence of radiographic CMC arthritis is 25% in men and 40% in women in those older than age 75. 2
SYMPTOMSPatients present with complaints of diffuse pain around the thenar musculature and dorsum of the thumb base. Symptoms can vary from occasional ache to severe pain and weakness that limit activities of daily living. Physical examination reveals tenderness to palpation over the dorsal or dorsoradial aspect of the CMC joint. Warmth or local edema may accompany the pain. The grind test produces crepitus and pain with axial compression and rotation of the thumb. Long standing CMC arthritis can lead to secondary deformity of the thumb metacarpophalangeal (MCP) joint. As the thumb becomes stiff and adducted over time, the MCP joint hyperextends to compensate for the proximal loss of motion.
DIFFERENTIAL DIAGNOSISPain around the base of thumb can be also due to de Quervain tenosynovitis of the first dorsal compartment, flexor carpi radialis (FCR)tendonitis, carpal tunnel syndrome, stenosing tenosynovitis of the flexor pollicis longus, and scaphoid pathology. Differential injections of lidocaine and/or cortisone into the suspected areas can be used to better localize the patient's source of pain.
ANATOMYThumb CMC joint is a saddle joint allowing a complex set of thumb motions: flexion, extension, adduction, abduction, and opposition. 3 This joint is stabilized by several key ligamentous structures. 4 The palmar oblique ligament, originating from the trapezium and inserting on the articular margin of the metacarpal base, provides static restraint to resist abduction, extension, and pronation forces. The dorsoradial ligament is the thickest CMC ligament and prevents dorsoradial translation or dislocation. The intermetacarpal ligament, originating from the base of radial base of the second metacarpal to the ulnar base of the first metacarpal, prevents radial translation.
PATHOPHYSIOLOGYThe exact etiology of thumb CMC arthritis remains unclear. Several intrinsic and extrinsic causes have been postulated with ongoing research efforts focused on further defining and therefore preventing basal thumb arthritis.Intrinsic causes include hypermobility, ligament laxity, and sex differences in anatomy, and/or hormonal differences. Women have higher incidence of thumb CMC arthritis, possibly related to the propensity for hypermobility secondary to hor...