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Incidence and Risk Factors

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DRUJ arthritis is degenerative or post-traumatic arthritis of the distal radioulnar joint, most commonly following distal radius malunion (60-70% of cases). It presents with ulnar-sided wrist pain, crepitus, and restricted forearm pronation/supination. The piano key sign (dorsally prominent ulna) and DRUJ grind test are key examination findings. Treatment options include activity modification and NSAIDs for mild disease, progressing to surgery for refractory cases: Darrach procedure (ulnar head resection) for low-demand elderly patients, Sauvé-Kapandji (DRUJ fusion with proximal ulna pseudarthrosis) for younger active patients, or DRUJ arthroplasty in select cases.

Distal radius malunion alters DRUJ biomechanics through several mechanisms including dorsal angulation increasing load on dorsal sigmoid notch, radial shortening creating positive ulnar variance and increased DRUJ pressure, and articular step-off creating point loading and accelerated cartilage wear. Chronic DRUJ instability from TFCC insufficiency leads to abnormal kinematics with repetitive subluxation, synovitis, and progressive cartilage degeneration.

History

Patients typically present with ulnar-sided wrist pain that is activity-related and worse with forearm rotation, gripping, and loading. Specific aggravating activities include turning doorknobs, using screwdrivers, wringing towels, push-ups, and keyboard use. Pain may radiate proximally into the forearm or distally into the ulnar digits. Mechanical symptoms including clicking, catching, or popping with rotation suggest instability or loose bodies.

History of antecedent trauma (particularly distal radius fracture) should be elicited, including mechanism, treatment received (operative versus non-operative), and healing complications. P

atients may report progressive worsening over months to years since the initial injury. In inflammatory arthropathy cases, systemic symptoms and involvement of other joints should be documented.

Physical Examination

The DRUJ grind test is performed by stabilizing the distal radius with one hand while grasping the ulnar head with the other, applying axial compression and rotating through pronation and supination. Crepitus and reproduction of pain indicate DRUJ arthritis. The piano key sign assesses DRUJ stability by applying dorsal and volar directed forces to the ulnar head while stabilizing the radius, looking for excessive translation and reproduction of symptoms.

Functional Impact

Functional deficits vary with severity but commonly include difficulty with activities requiring forearm rotation (turning keys, opening jars, using screwdrivers), reduced grip strength due to pain inhibition (20-40% reduction typical), inability to bear weight on extended wrist (push-ups, yoga), and difficulty with keyboard and mouse use. Patients may develop compensatory strategies such as rotating the entire arm from the shoulder rather than forearm rotation.

Radiographic Evaluation

Standard wrist radiographs (PA, lateral, oblique) form the initial imaging assessment. PA view demonstrates joint space narrowing at the DRUJ, subchondral sclerosis, ulnar head deformity or flattening, and cystic changes in advanced cases. Assessment of ulnar variance is critical, as positive ulnar variance (ulnar head extends beyond radial articular surface) increases DRUJ loading and accelerates arthritis. Comparison with the contralateral uninjured wrist is valuable.

Advanced Imaging

Computed tomography (CT) is the gold standard for detailed assessment of DRUJ arthritis. CT clearly demonstrates sigmoid notch morphology and articular surface irregularity, ulnar head shape and arthrosis, degree of subluxation or dislocation, presence of loose bodies or osteophytes, and quality of bone stock for surgical planning. Bilateral CT with forearm in pronation, neutral, and supination allows assessment of dynamic stability and subluxation patterns.

Magnetic resonance imaging (MRI) evaluates soft tissue structures including TFCC integrity (central perforation, peripheral detachment), extensor carpi ulnaris (ECU) tendon pathology, interosseous membrane injury, and bone marrow edema indicating active arthritic process. MRI is particularly valuable when concomitant soft tissue pathology is suspected or when evaluating younger patients where TFCC repair might be considered.

Diagnostic Injection

Fluoroscopically guided DRUJ corticosteroid injection serves diagnostic and therapeutic purposes. Temporary complete pain relief confirms DRUJ arthritis as the primary pain generator, which is valuable when multiple potential sources exist (ulnar impaction syndrome, TFCC tears, ECU tendinopathy). The injection typically uses corticosteroid (triamcinolone 40mg) with local anesthetic (lidocaine or bupivacaine), injected into the DRUJ space under fluoroscopic guidance.

Staging by Etiology

DRUJ arthritis is staged by etiology to guide treatment. Post-traumatic arthritis (most common) results from distal radius malunion, intra-articular fracture, chronic DRUJ instability, or Essex-Lopresti injury. Inflammatory arthritis includes rheumatoid arthritis (often bilateral with synovitis and bone erosion), psoriatic arthritis, and crystalline arthropathy. Primary osteoarthritis occurs without clear antecedent trauma and is less common. Neuromuscular causes include cerebral palsy and other spasticity disorders with chronic abnormal forces.

Severity Grading

Non-Operative Treatment

Non-steroidal anti-inflammatory drugs (NSAIDs) provide symptomatic relief. Topical NSAIDs may be preferred for patients with GI concerns. Splinting in neutral forearm rotation with a long arm splint or Muenster-type orthosis reduces symptoms by limiting rotation, worn during aggravating activities or at night. Custom thermoplastic splints can be fabricated by hand therapists.

Corticosteroid injection into the DRUJ provides temporary relief in 60-70% of patients, lasting weeks to months. Repeat injections may be performed but are generally limited to 2-3 per year. Physical therapy focuses on maintaining range of motion and strengthening forearm and wrist muscles to provide dynamic stability.

Indications for Surgery

Surgery is considered when conservative management fails to control symptoms after 3-6 months, pain significantly limits function or quality of life, progressive instability develops, or patients have high functional demands incompatible with conservative restrictions. Relative contraindications include active infection, severe osteoporosis (compromises fixation for Sauvé-Kapandji), unrealistic expectations, and significant medical comorbidities precluding surgery.

Surgical Options Overview

Darrach Procedure

The Darrach procedure involves excision of the distal ulna (typically 1.5-2.5cm of ulnar head and neck). The technique uses a dorsal or ulnar approach to the DRUJ, subperiosteal dissection to protect the TFCC remnant and ECU tendon, and transection of the ulna at an appropriate level (preserving adequate ulna for forearm function). Soft tissue stabilization with ECU tendon or TFCC remnant coverage of the ulnar stump reduces instability.

Indications for Darrach include elderly low-demand patients (age greater than 60 years), severe DRUJ arthritis with ulnar head destruction, rheumatoid arthritis with bone erosion, and revision of failed other procedures. Advantages include technical simplicity, reliable pain relief, and no implant-related complications. Disadvantages include ulnar stump instability (painful prominence of ulna with gripping), reduced grip strength (10-20% reduction), and cosmetic concerns (visible depression at DRUJ).

Postoperative management involves short arm splint for 2 weeks followed by progressive range of motion. Full activity is typically allowed at 6-8 weeks. Outcomes include good pain relief in 75-85% but with variable grip strength recovery and potential ulnar stump instability requiring subsequent soft tissue stabilization.

Sauvé-Kapandji Procedure

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The Sauvé-Kapandji procedure creates a radioulnar fusion at the DRUJ level combined with an ulnar pseudarthrosis proximal to the fusion site. The technique involves exposure of the DRUJ, preparation of articular surfaces (radius sigmoid notch and ulnar head), fusion of radius to ulna in neutral rotation using K-wires or compression screw, and creation of a 1-1.5cm segment of ulna resection proximal to the fusion (allowing forearm rotation through the pseudarthrosis).

Postoperative management includes long arm cast or splint for 4-6 weeks until fusion is evident, followed by protected motion for 2-4 additional weeks. Full unrestricted activity is allowed at 3-4 months. Outcomes are generally excellent with 85-90% patient satisfaction, good pain relief, and maintained rotation (80-90% of contralateral side).

Hemiresection-Interposition Arthroplasty (Bowers)

The Bowers procedure involves resection of the ulnar head articular surface (removing approximately 50% of the head) with soft tissue interposition (typically palmaris longus autograft or allograft). The technique preserves the ulnar styloid and TFCC attachments while removing the arthritic ulnar head dome. Interposition material is secured between the remaining ulna and radius to prevent bone-on-bone contact and provide cushioning.

Indications include intermediate-age patients (45-65 years), moderate DRUJ arthritis with preserved ulnar styloid and TFCC, and patients desiring stability without fusion. Advantages include preservation of TFCC attachment providing stability, less extensive than Darrach (preserves more ulna), and maintained forearm rotation. Disadvantages include technically demanding, potential for inadequate resection with recurrent pain, and interposition material attenuation over time with symptom recurrence.

Outcomes are good to excellent in 70-80% of patients at short to intermediate term (2-5 years), with some reports of declining results at longer follow-up. The procedure serves as an intermediate option between conservative management and more extensive salvage procedures.

DRUJ Prosthetic Arthroplasty

DRUJ prosthetic replacement uses implants that reconstruct the ulnar head with a metal stem and articular component. Several designs exist including constrained (linked radius and ulna components) and unconstrained (ulnar head replacement only) systems. The procedure involves DRUJ exposure, excision of arthritic ulnar head, preparation of ulnar canal for stem, and implantation of the prosthesis with secure fixation.

Indications include younger patients with isolated DRUJ arthritis and intact TFCC, failed prior DRUJ procedures requiring revision, and high functional demands requiring maximal function preservation. Advantages include maintained DRUJ anatomy and stability, good forearm rotation, and potential for improved outcomes over ulnar head excision. Disadvantages include implant cost, risk of loosening or failure (10-15% at 5-10 years), polyethylene wear, and technical challenges with revision if needed.

Long-term outcome data is limited compared to established procedures like Darrach and Sauvé-Kapandji. The procedure is reserved for carefully selected patients in centers with expertise in DRUJ arthroplasty.

Surgical Complications

Early complications include wound healing problems (infection, dehiscence, hematoma), nerve injury (dorsal sensory branch of ulnar nerve most common), and early instability. Late complications include ulnar stump instability after Darrach (30-40% incidence, higher in younger active patients), nonunion after Sauvé-Kapandji fusion (5-10%), persistent or recurrent pain (10-20% across all procedures), prosthesis loosening or wear (10-15% at 5-10 years for DRUJ arthroplasty), and complex regional pain syndrome (rare, less than 5%).

Outcomes and Prognosis

Patient satisfaction and functional outcomes vary by procedure and patient selection. Darrach procedure achieves good pain relief in 75-85% but with variable grip strength (typically 80-90% of contralateral) and risk of ulnar stump instability especially in younger patients. Sauvé-Kapandji achieves excellent outcomes in 85-90% with good pain relief, maintained rotation (80-90%), and stable DRUJ, making it preferred for younger active patients.

Hemiresection-interposition achieves good to excellent outcomes in 70-80% at intermediate follow-up but may deteriorate over longer term. DRUJ prosthetic arthroplasty has promising early results but limited long-term data; preliminary reports suggest 80-85% satisfaction at 5 years with 10-15% revision rate.

Factors predicting better outcomes include appropriate procedure selection for patient age and activity level, absence of inflammatory arthropathy, good bone stock, and realistic patient expectations. Poor prognostic factors include workers' compensation or litigation, unrealistic expectations, severe osteoporosis, and active smoking (affects healing).

Australian Specific Considerations

DRUJ arthritis is managed by hand and wrist surgeons in both metropolitan and regional centres across Australia. Public hospital hand services provide comprehensive assessment and treatment, with surgical procedures performed at major teaching hospitals. Private hand surgery practices offer alternative pathways with variable out-of-pocket costs depending on insurance coverage.

Imaging is readily available through public and private radiology services. CT scanning is essential for surgical planning and is accessible with appropriate referral. Medicare rebates apply for consultations, imaging, and surgical procedures (item 46441 for Darrach, 46438 for Sauvé-Kapandji, 46444 for hemiresection arthroplasty).

Hand therapy is critical for both conservative and postoperative management, provided by certified hand therapists in public hospital clinics and private practices. Customized splinting, strengthening programs, and functional retraining optimize outcomes. Medicare rebates apply for hand therapy with appropriate referral.

Workers' compensation considerations are important for occupational injuries or conditions exacerbated by work duties. Independent medical examinations, detailed causation assessment, and liaison with rehabilitation coordinators may be required. Return-to-work planning with graduated duties and ergonomic modifications facilitates successful outcomes.

This topic provides comprehensive coverage of DRUJ arthritis aligned with FRACS examination requirements, emphasizing etiology recognition, patient-specific surgical selection, and evidence-based management of this common yet challenging wrist condition.