RA- DRUJ

Question 1

2 main DRUJ deformities in RA

Answer 1

1. Caput ulna = dorsal prominence of ulna head
   - can be relative (volar subluxation of carpus) or absolute (disruption of radioulnar ligaments and TFCC)
2. Positive ulnar variance = causes ulnocarpal abutment

Question 2

5 surgical options for DRUJ pathology in RA

Answer 2

5 joint sacrificing options:

1. Wafer procedure
   - involves arthroscopically removing 2-4mm of articular cartilage and bone under TFCC
2. Darrach procedure = ulnar head resection
3. Sauve-Kapandji procedure = DRUJ arthrodesis and distal ulna resection (creates a proximal pseudoarthrosis to allow forearm rotation)
4. Ulnar hemiresection arthroplasty
   - involves removing the radial 1/2 of the ulnar head
   - requires an intact/ functioning TFCC
5. Ulnar head replacement
   - severe ulnocarpal arthritis
   - salvage option with a failed Darrach procedure
   - Wafer and hemiresection arthroplasty probably not ideal given TFCC involvement in RA
   - Darrach and Sauve-Kapandji are main ones in RA

Question 3

Darrach procedure for DRUJ pathology in RA:
Advantages
Disadvantages
Indications
Contraindications
Technique

Answer 3

1. Advantages
   - technically easier
   - faster recovery = shorter immobilisation
2. Disadvantages = 4 main complications are
   - stump instability
   - radioulnar convergence
   - ulnocarpal translocation
   - weakness
3. Indications
   - elderly low-demand patients
   - ulnocarpal and DRUJ arthritis
   - RA patients without ulnocarpal translocation
4. Disadvantages = see complications above
5. Technique
   - Subperiosteal exposure of the ulnar head
   - Ulnar osteotomy proximal to sigmoid notch (max 2cm)
   - Preservation of ulnar styloid and its attachments
   - Bevel end of stump to smooth bullet shape to prevent tendon attrition
   - Interposition of PQ between radius and stump to prevent radioulnar convergence
   - Volar capsulodesis to dorsal ulna to stabilise stump

Question 4

Sauve-Kapandji procedure from DRUJ pathology in RA:
Advantages
Disadvantages
Indications
Contraindications
Technique

Answer 4

1. Advantages
   - less stump instability
   - no radioulnar convergence
   - no ulnocarpal translocation
   - less weakness
2. Disadvantages
   - technically harder
   - slower recovery = 6wks immobilisation
   - complications = stump instability, nonunion
3. Indications
   - active high-demand patients
   - ulnocarpal and DRUJ arthritis
   - RA patients with ulnocarpal translocation
4. Contraindications = risk factors for nonunion
5. Technique
   - Dorsal approach through 5th extensor compartment
   - L-shaped capsulotomy to expose DRUJ
   - Pass 2x K-wires into ulnar head
   - Prepare DRUJ surfaces
   - Centre ulnar head in sigmoid notch
   - Advance wires across sigmoid notch into radius
   - Pass 2x cannulated screws over wires
   - Resect 10mm of ulna proximal to DRUJ