Trapeziometacarpal Arthritis

Published on 11/03/2015 by admin

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CHAPTER 31 Trapeziometacarpal Arthritis

Trapeziometacarpal arthritis is a common condition seen in hand surgery practice. The typical patient is a middle-aged woman who describes the gradual onset of thumb basilar joint discomfort, pain with gripping or pinching, difficulty opening jars, and diminished strength. Treatment options depend on the symptoms, the radiographic stage, and the preferences of the surgeon and patient.

ANATOMY

The anatomy of the thumb basilar joint is complex. This biconcave-convex saddle-shaped joint has minimal bony constraints, permitting a wide arc of mobility and facilitating prehension. The ligamentous structures about the elbow promote stability, and the muscular forces about the thumb confer large forces on the thumb in pinch and grasp.¹ Basilar joint arthritis at the thumb is related to a variety of factors, including age and use, genetics, and hormonal effects. Bettinger and colleagues described the complex ligamentous structure about the trapeziometacarpal joint and 16 ligaments that stabilize the joint.² The important anterior oblique (beak) ligament is considered the primary stabilizer of the trapeziometacarpal joint.³ Bettinger and coworkers described superficial and deep components of the beak ligament.² The superficial and deep anterior oblique ligament, the dorsoradial ligament, the posterior oblique ligament, the ulnar collateral ligament, the intermetacarpal ligament, and the dorsal intermetacarpal ligament stabilize the thumb carpometacarpal (CMC) joint; the other nine ligaments stabilize the trapezium.² The degree of anterior oblique ligament degeneration corresponded with the extent of arthritis⁴ in a cadaveric study. Laxity of the beak ligament may alter the contact pressures and congruity of the joint, leading to joint subluxation and arthritic changes.⁵

PATIENT EVALUATION

History and Physical Examination

The history should include information regarding age, gender, and handedness. Attention should be paid to duration of symptoms, exacerbating and relieving factors, and the nature and location of discomfort. Occupations and avocations should be explored, particularly in relation to symptoms. The patient’s prior treatments and response to these should be explored.

Examination may elicit the shoulder sign, in which the CMC joint is subluxated and the metacarpus adducted. The CMC grind test is performed by axial loading and circumduction of the metacarpal on the trapezium. Concomitant or alternative diagnoses should be ruled out; patients may have carpal tunnel syndrome (estimated to coexist in 43% of cases), deQuervain’s tendonitis, or hypermobility of the CMC joint.³^,⁶ The status of the scaphotrapeziotrapeziod (STT) joint and arthritis in this joint should be assessed. Range of motion at the wrist and thumb should be documented, including thumb abduction and opposition (i.e., ability touch the base of the small finger) and metacarpophalangeal (MCP) motion. The MCP joint must be examined in hyperextension, which exacerbates metacarpal adduction. If MCP hyperextension is not addressed during ligament reconstruction, the stresses on the reconstruction may lead to failure. If hyperextension is greater than 30 degrees, the MCP joint should be treated with fusion, capsulodesis, or sesmoidectomy.⁷ If hyperextension is less than 30 degrees, the surgeon can consider pinning the MCP joint with a Kirschner wire for 4 to 6 weeks.

Diagnostic Imaging

Radiographs that should be obtained include posteroanterior, lateral, and Bett’s views. From plain film radiographs, the extent of disease may be staged according to the system described by Eaton.⁸ However, it is important to consider the patient’s radiographic stage and symptoms together. Radiographs often demonstrate severe arthritis in a patient with only minimal symptoms; conversely, some patients have minimal changes on radiographs but are quite symptomatic.

TREATMENT

Indications and Contraindications

Painful first CMC joint arthritis that interferes with activities and has failed nonoperative management is an indication for surgery. Contraindications include active infection.

TREATMENT

Many patients respond to a nonoperative approach. Consideration should be given to activity modification, thumb spica splinting, use of nonsteroidal anti-inflammatory medications, and intra-articular corticosteroid injections. These forms of management are often most helpful in the early stages of the disease.

Eaton divided thumb CMC joint arthritis into stages, which are useful for deciding on treatment options.⁸ The stage I joint is essentially radiographically normal but may have slight widening caused by synovitis or effusion. It may be treated by conservative means, such as nonsteroidal anti-inflammatory drugs and immobilization, but some authorities advocate ligament reconstruction, arthroscopy, or metacarpal osteotomy for stage I disease. Stage II disease is characterized by further joint space narrowing, changes with osteophyte formation (<2 mm), and mild to moderate joint subluxation. Stage III disease is characterized by moderate joint subluxation and prominent osteophyte formation (>2 mm), and stage IV is pantrapezial arthritis. Stages II through IV may be treated by arthroscopic or by open partial or complete trapeziectomy, with or without ligament reconstruction and interposition, fusion, or arthroplasty.

Patients with Eaton stage I, II, or III disease may be candidates for arthroscopy to determine the true extent of joint changes. In the early stages, in which the articular cartilage is intact but synovitic changes or ligamentous laxity is present, the pathology may be addressed by débridement and capsular shrinkage of the ligaments. Patients with more apparent changes, such as attenuation of the anterior oblique ligament and partial volar cartilage loss, may be candidates for extension osteotomy or arthroscopic débridement and interposition arthroplasty, whereas those with widespread cartilage loss may do best with arthroscopic débridement and interposition arthroplasty or conversion to an open procedure.⁹^,¹⁰

Arthroscopic Technique

The technique for arthroscopy of the CMC joint has previously been described.¹¹^,¹² The thumb is suspended in traction (Fig. 31-1), and surface landmarks are marked (Fig. 31-2). The joint is penetrated with a needle; fluoroscopy can help to confirm correct entry into the trapeziometacarpal joint rather than the STT joint. After the needle position is confirmed, the joint is insufflated with saline.

FIGURE 31-1 Arthroscopic setup.

FIGURE 31-2 Surface landmarks are marked.

The 1-R (radial) and the 1-U (ulnar) portals are used (Fig. 31-3). The 1-R portal is made between the abductor pollicis longus and flexor carpi radialis tendons at the CMC joint level. The 1-R portal is useful to examine the dorsal radial, palmar oblique, and ulnar collateral ligaments, and it provides a view of the radial aspect of the joint. It also allows visualization of the intermetacarpal ligament and the distal insertions of the anterior oblique ligament into the first metacarpal (Fig. 31-4).