Arthritis of the MCP or PIP joints may be idiopathic, posttraumatic, or inflammatory (RA).

Idiopathic osteoarthritis involves the distal interphalangeal joint most commonly, but the PIP joint is also affected; the MCP joint is less commonly involved.

The PIP joint is the most frequently traumatized finger joint and, thus, has the highest incidence of posttraumatic arthritis. Given the shortcomings of the salvage procedures for PIP joint arthritis, an anatomic joint reduction and aggressive restoration of the normal anatomy after trauma is critical to reduce the risk of arthritis.

The bony congruity of the PIP joint makes it poorly tolerant of any loss of cartilage; deformity and loss of motion may progress quickly.

Inflammatory arthritis (RA) most commonly affects the MCP joint but may also involve the PIP joint. In RA, a proliferative synovitis compromises the soft tissue support of the affected joint and may lead to the characteristic deformities at the MCP joint, including volar subluxation (and a flexed posture) and ulnar deviation. The PIP joint is less predictable because attenuation of the volar supporting structures may lead to joint hyperextension, whereas compromise of the central slip insertion will lead to a joint flexion deformity.

The efficacy of the disease-modifying antirheumatic drugs has dramatically decreased the need for joint arthroplasty in these patients.

The natural history of osteoarthritis or posttraumatic arthritis of the PIP joint is progression with loss of motion, pain, and, in some patients, deformity. The MCP joint is less commonly affected and is also more tolerant of arthritis, given its increased mobility in all planes.

In the patient with severe RA not controllable by disease-modifying antirheumatic drugs, joint inflammation will lead to progression of the arthritis.

The functional effect of the arthritis depends on the degree of involvement, the specific joint, and the involvement of the adjacent joints.

It is vital that the surgeon understand how the arthritis specifically affects the function of a particular patient. This depends on many factors, including adjacent joint involvement, specific patient activities, and the degree of pain experienced.

Posteroanterior and lateral plain radiographs provide sufficient diagnostic information. Occasionally, oblique radiographs are helpful (FIG 1).

Magnetic resonance imaging (MRI) and computed tomography (CT) are of limited use in the evaluation of the MCP and PIP joints.

Anti-inflammatory medications

Steroid injections

Hand therapy to address contractures, including splinting

Surgery is considered if nonoperative management fails. Given the limitations of silicone implant arthroplasty as noted in the following text, the decision for surgical intervention should be patient driven.

The best outcome is expected in patients with joint-based pain and a well-preserved arc of motion and minimal deformity. Patients without pain and presenting with deformity or a lack of motion are not ideal candidates for arthroplasty, especially if the adjacent joints are functioning well. Joint arthroplasty, of any variety, does not reliably increase motion at long-term follow-up.

In RA, an ulnar drift and volar subluxation of the MCP joints with a flexion posture of the joints may lead to weakness and a loss of the ability to grasp larger objects. These deformities are also unsightly. Surgical intervention in these patients can be expected to improve the appearance and function of the hand.