Clinical Guide: The Sauvé-Kapandji Procedure (DRUJ Arthroplasty)

1. Comprehensive Introduction & Overview

The Distal Radioulnar Joint (DRUJ) is a complex pivot joint essential for the rotation of the forearm (pronation and supination). When this joint suffers from chronic instability, degenerative arthritis, or post-traumatic malunion, the resulting pain and functional limitation can be debilitating.

The Sauvé-Kapandji procedure, first described in 1936, remains a gold-standard "salvage" operation for complex DRUJ pathology. It is a combined procedure involving two distinct components:
1. Arthrodesis: The fusion of the distal radius to the distal ulna.
2. Pseudarthrosis: The creation of a stable, functional gap (resection) in the distal ulna shaft to restore forearm rotation.

By sacrificing the articulation of the DRUJ and converting it into a fused segment, while creating a new, proximal "hinge" of sorts via the ulnar resection, the surgeon eliminates the grinding pain of the arthritic joint while preserving (and often restoring) the mechanical ability to rotate the forearm.

2. Technical Specifications & Biomechanics

The Mechanism of Action

In a healthy wrist, the ulnar head rotates within the sigmoid notch of the radius. In cases of severe osteoarthritis or rheumatoid destruction, this movement becomes painful. The Sauvé-Kapandji procedure essentially reconfigures the distal forearm anatomy:

• The Fusion (Arthrodesis): By fusing the distal radius and ulna, the surgeon eliminates the articular surface that is causing pain. This typically requires decortication of the sigmoid notch and the corresponding ulnar head, followed by fixation (usually with screws or plates).
• The Pseudarthrosis (Resection): A segment of the ulna (approximately 1–2 cm) is removed proximal to the fusion site. This allows the proximal ulnar stump to rotate independently of the fixed distal ulnar remnant. The soft tissues surrounding this gap are carefully managed to prevent unwanted bony regrowth (synostosis).

Comparative Biomechanics

3. Clinical Indications & Usage

Indications for Surgery

The Sauvé-Kapandji procedure is indicated for patients who have failed conservative management (physical therapy, splinting, NSAIDs, or corticosteroid injections).

1. Post-traumatic Arthritis: Following distal radius fractures where the DRUJ was involved and has malunited.
2. Rheumatoid Arthritis: Destruction of the DRUJ is common in RA; this procedure provides significant pain relief.
3. Chronic DRUJ Instability: When ligamentous reconstruction has failed or is not anatomically viable.
4. Essex-Lopresti Lesions: Late-stage sequelae involving proximal migration of the radius.
5. Kienböck’s Disease: Specifically when secondary DRUJ arthrosis is present.

Patient Selection Criteria

• Failure of conservative treatment: Minimum 3–6 months.
• Symptomatic DRUJ: Pain must be localized to the distal ulnar aspect.
• Adequate Bone Stock: Necessary for the fusion component.
• Patient Expectations: Realistic understanding that while pain is reduced, the procedure is a salvage operation, not a restoration of "perfect" anatomy.

4. Pre-Operative Preparation

Preparation is critical to ensure successful fusion and recovery:
* Imaging: Standard AP/Lateral radiographs, CT scans (to evaluate the sigmoid notch), and occasionally MRI to assess the Triangular Fibrocartilage Complex (TFCC) if clinical exams are ambiguous.
* Physical Exam: Assess the "Piano Key" sign (dorsal instability) and specifically test the range of motion (ROM) in pronation and supination.
* Medical Optimization: Smoking cessation is mandatory; nicotine significantly increases the risk of non-union at the fusion site.

5. The Procedure: Step-by-Step

Phase I: Exposure

A longitudinal incision is made over the dorsal distal ulna. The extensor retinaculum is identified and lifted (usually the 5th and 6th compartments).

Phase II: The Arthrodesis

1. The distal radioulnar joint is exposed.
2. The articular cartilage is removed from both the sigmoid notch of the radius and the ulnar head.
3. The bones are held in a neutral position (or slight supination, depending on surgeon preference).
4. Fixation: Compression screws or a low-profile locking plate are used to achieve rigid fixation between the radius and ulna.

Phase III: The Pseudarthrosis

1. A segment of the ulna (1.5 cm) is resected proximal to the fusion site.
2. The ends of the remaining ulnar bone are rounded off to prevent impingement.
3. Interposition: Soft tissue (fascia or muscle) is often interposed between the cut ends of the bone to minimize the risk of the bone ends fusing back together (cross-union).

Phase IV: Closure

The extensor retinaculum is repaired, and the skin is closed in layers. A bulky dressing is applied, often with a volar splint.

6. Post-Operative Recovery Protocol

The recovery timeline is structured to protect the fusion while encouraging early mobilization.

• Weeks 0–2: Immobilization in a splint. Focus on elevation and edema control.
• Weeks 2–6: Transition to a removable orthosis. Gentle active range of motion (AROM) of the fingers and thumb.
• Weeks 6–12: Radiographic assessment of fusion. If fusion is solid, initiate active supination/pronation exercises.
• Months 3–6: Strengthening exercises. Return to light activity. Heavy lifting (typically >10 lbs) is discouraged until the 6-month mark.

7. Potential Complications

While highly effective, the procedure is not without risks:

1. Non-union: The fusion between the radius and ulna fails to consolidate.
2. Synostosis: The pseudarthrosis gap closes, and the ulna re-fuses to the radius, effectively locking the forearm in one position.
3. Ulnar Stump Instability: The proximal ulnar stump becomes painful or clicks against the radius.
4. Infection: Standard surgical site infection risks.
5. Complex Regional Pain Syndrome (CRPS): A rare but serious complication involving chronic neuropathic pain.

8. Alternative Treatments

• Darrach Procedure: Resection of the distal ulnar head. (Risk: ulnar carpal instability/impingement).
• Hemiresection Interposition Arthroplasty (HIA): Resection of the ulnar head and stabilization with a tendon graft.
• Total DRUJ Replacement: A newer, prosthetic-based solution for younger, lower-demand patients.

9. FAQ: Frequently Asked Questions

Q1: Is the Sauvé-Kapandji procedure painful?
A: Post-operative pain is managed with multimodal analgesia. Once the fusion is solid, most patients report a significant reduction or complete elimination of their pre-operative "grinding" pain.

Q2: How long does the fusion take?
A: Bony union typically takes 8 to 12 weeks. Smoking significantly delays this process.

Q3: Will I lose strength in my wrist?
A: You may experience a slight reduction in grip strength compared to a healthy, uninjured wrist, but you will likely be stronger than you were with a painful, arthritic joint.

Q4: Can I play sports after this surgery?
A: Once fully recovered (usually 6 months), most patients return to recreational sports. High-impact contact sports are generally discouraged.

Q5: What is the risk of the bone growing back together?
A: Synostosis (the gap filling with bone) occurs in 5–10% of cases. Surgeons mitigate this by interposing soft tissue and ensuring a sufficient resection gap.

Q6: Is this surgery reversible?
A: It is considered a salvage procedure. Reversing it is extremely difficult and rarely indicated.

Q7: Will I need a plate in my wrist forever?
A: Typically, yes. Unless the hardware causes irritation, it is left in place to maintain the structural integrity of the fusion.

Q8: How does this differ from a Darrach procedure?
A: The Darrach procedure leaves the distal ulna "floating," which can lead to instability. The Sauvé-Kapandji provides a more stable distal construct by fusing the radius to the ulna.

Q9: Who is the ideal candidate?
A: A patient with chronic, localized DRUJ pain who has exhausted all non-surgical options and desires a stable, pain-free wrist for daily activities.

Q10: What happens if the fusion fails?
A: If the fusion fails (non-union), the surgeon may need to perform a revision bone graft procedure to achieve stability.

10. Clinical Summary Table: Expected Outcomes

Disclaimer: This guide is for educational purposes for healthcare professionals and patients and does not constitute formal medical advice. Always consult with a board-certified orthopedic surgeon specializing in hand and upper extremity surgery for individual clinical management.