What is the diagnosis and treatment for chronic joint deformities, such as ulnar deviation and swan neck deformities, with minimal tenderness in metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints?

Diagnosis: Rheumatoid Arthritis with Chronic Deformities

Based on the chronic nature of ulnar deviation and swan neck deformities with minimal joint tenderness, this presentation is most consistent with long-standing rheumatoid arthritis that has progressed to structural joint damage. The absence of significant tenderness suggests the inflammatory phase is either well-controlled or has "burned out," leaving behind fixed mechanical deformities 1, 2.

Key Diagnostic Features

Joint Distribution Pattern:

• Ulnar deviation primarily affects the MCP joints and represents a classic rheumatoid arthritis deformity pattern 1, 2
• Swan neck deformities (PIP hyperextension with DIP flexion) in RA typically originate from MCP joint pathology, with secondary effects on the PIP joints 3, 4
• The combination of MCP and PIP involvement with minimal tenderness indicates advanced structural disease rather than active synovitis 1

Distinguishing from Other Conditions:

• Hand osteoarthritis targets DIP joints (Heberden nodes), PIP joints (Bouchard nodes), and thumb base, but does NOT typically cause ulnar deviation or swan neck deformities 5
• Psoriatic arthritis can affect DIP joints and may show asymmetric involvement with dactylitis, which differs from the symmetric pattern described 5, 1
• The minimal tenderness argues against active inflammatory arthritis from other causes 5

Staging the Deformities

Critical Assessment for Treatment Planning:

The flexibility of the deformities determines surgical approach 2, 4:

• Stage 1 (Flexible): Deformities can be passively corrected to neutral position - soft tissue procedures alone may suffice 2, 4
• Stage 2 (Partially Fixed): Limited passive correction possible - may require combined soft tissue and joint procedures 4
• Stage 3 (Fixed): No passive correction possible - requires arthroplasty or arthrodesis 2, 4

Test each affected joint by attempting passive correction to neutral position to determine stage 4.

Treatment Algorithm

For Flexible Deformities (Passively Correctable)

Soft tissue reconstruction is the preferred approach when joint structures remain relatively intact 2, 6:

• Swan neck deformity: PIP joint tenodesis using half of the flexor digitorum superficialis tendon sutured to the A2 pulley provides reliable long-term correction, with mean PIP flexion gains of 26° and hyperextension correction of 33° 6
• Ulnar deviation: Soft tissue-only procedures (extensor tendon centralization, intrinsic muscle release, collateral ligament reconstruction) are as effective as implant arthroplasty when joints are not destroyed 2
• Postoperative splinting in 20° PIP flexion for 4 weeks is required 6

For Fixed Deformities (Not Passively Correctable)

Implant arthroplasty becomes necessary when joint destruction prevents manual reduction 2, 4:

• Silicone or pyrocarbon MCP joint arthroplasty for ulnar deviation with destroyed joints 2
• PIP joint arthroplasty or arthrodesis for fixed swan neck deformities with articular cartilage destruction 4
• Arthrodesis is preferred over arthroplasty when severe joint destruction exists 2

Medical Optimization

Ensure rheumatoid arthritis is medically controlled before surgery 2:

• Disease-modifying antirheumatic drugs (DMARDs) with methotrexate as anchor drug should be optimized 7
• Biologic agents may be needed for difficult-to-control disease 2
• Surgery timing should occur during periods of good disease control 2

Critical Pitfalls to Avoid

Do not perform soft tissue procedures alone on fixed deformities - this leads to recurrence and poor outcomes 4. The stage of deformity (flexible vs. fixed) must be accurately assessed before choosing the surgical approach 4.

Address wrist deformities before or concurrent with finger procedures - wrist pathology contributes to ulnar deviation and must be corrected for lasting results 2.

Consider cervical spine status and overall medical condition - rheumatoid patients may have atlantoaxial instability requiring evaluation before anesthesia 4.

Evaluate for corticosteroid use - chronic steroid therapy affects wound healing and surgical planning 4.

Expected Outcomes

For flexible deformities treated with soft tissue procedures: 19 of 23 fingers (83%) achieve good to excellent results at 5-year follow-up 6. Functional improvement occurs in all patients when appropriate staging and technique are used 6.

For advanced disease requiring implant arthroplasty: outcomes depend on proper patient selection and addressing all contributing deformities (wrist, MCP, PIP) in a coordinated fashion 2.