DRUJ & TFCC Pathology

Problems involving the DRUJ may include

• Instability alone
• Arthrosis alone
• Instability and arthrosis

Anatomy - Stabilisers of the DRUJ

Intrinsic Stabilisers

• TFCC superficial and deep fibres (esp. ligamentum subcruentum)
  • Transmits 20% load in neutral ulna variance
  • 5% if negative and 40% if positive
• Ulna collateral ligament
• Dorsal and Volar Radio-Ulnar ligaments
• Joint capsule
• Congruency of DRUJ
  • Poor due to different radii of curvature
  • Many people have a very shallow sigmoid notch

Extrinsic Stabilisers

• ECU subsheath
• Pronator Quadratus
• Long flexors and extensors (dynamic stability)

Examination of the DRUJ

• Examine stability and associated structures → TFCC, ECU, etc.
• Examine stability by translation → arm in neutral, supination, and pronation
• Assess for proximal pain → Essex Lopresti lesion
• Press test → is there ulna pain when pushing up from a seated position?

Acute Injuries

Isolated DRUJ Dislocation

• Uncommon and virtually always dorsal
• Occurs with hyper-pronation
• May be irreducible due to ECU or TFC interposition

Injury with Associated Fracture

• More common
• Distal Radius, Essex Lopresti lesion, Galeazzi, or Ulna Styloid base fracture
• Distal Radius - Shortening causes ulna-sided impaction and pain
• Loss of volar tilt >20° causes rotational problems
• Styloid base fractures can represent TFCC avulsion fractures

Treatment Principles – Acute Instability

• Reduce any isolated dislocations closed
• If stable → plaster in supination
• If unstable → 2 x K-wires
• Anatomically reduce any distal radius fracture
  • Ensure length and volar tilt corrected
  • Re-test stability
  • If still unstable and no ulna styloid fracture
    • K-wires to hold reduction
    • TFCC likely avulsed
    • Explore TFCC arthroscopically or open for stabilisation
    • If stable → above elbow plaster for 4 weeks
  • If associated large styloid fracture and unstable despite distal radius fixation
    • Consider ORIF of ulna styloid with small screw or TBW

Treatment Principles - Chronic Instability

Patient Symptoms

• Clunking
• Ulna-sided pain (not always)
• Reduced rotation, especially supination

Address Distal Radius Malunion

• Consider extra-articular or intra-articular osteotomy as needed and plating
• Ring et al. showed this reliably stabilised DRUJ and restored supination
• If malunion is not a factor, consider:

Ulna Shortening Osteotomy

• Does not address the cause
• May provide pain relief and tighten capsule around DRUJ

Reconstruction of DRUJ

• Chronic TFCC tears are not repairable
• Use tendon graft with drill holes in radius and fovea to replicate TFCC

Deepen Sigmoid Notch (Sigmoid Osteoplasty)

• Useful if shallow notch (common in many people)
• Better for functional rather than frank instability

Management of Instability - Salvage Options

• If all else fails and patient remains symptomatic:

Ulna Head Replacement

• Good option but lacks long-term data

Ulna Head Deletion – Darrach or Suave-Kapandji

• Last resort procedures for low-demand patients
• Do not restore good function and may cause chronic pain
• Darrach Procedure
  • More complications but easier to perform
  • Better for elderly, low-demand patients

Distal Radio-Ulnar Fusion

• Extreme procedure – reserved for select cases
• Creates a one-bone forearm

Management of DRUJ Arthrosis (With or Without Instability)

• Rotation is limited and painful
• DRUJ may be prominent with osteophytes
• May be a Vaughn-Jackson lesion → attrition of EDM or EDC

Treatment Options

• Soft tissue procedures fail due to arthrosis
• Similar options to instability, except soft tissue procedures
  • Osteophyte excision
  • Darrach or Suave-Kapandji procedures
  • Ulna head replacement
  • DRUJ replacement (very new and unproven)

TFCC Anatomy

Main Components of TFCC

1. Dorsal & Volar Radio-Ulnar Ligaments
2. Ligamentum Subcruentum
3. Articular Disk
4. Meniscal Homologue
5. ECU Subsheath
6. UCL (Ulnar Collateral Ligament) of the Wrist
7. Ulno-Lunate and Luno-Triquetral Ligaments

Vascularity

• Periphery is vascular
• Central part is avascular

Palmar Classification of TFCC Tears

Type 1 – Traumatic

• Associated with distal radius fractures

Subtypes

• 1a: Central perforation → Debride and leave 2mm stable rim
• 1b: Ulna detachment → Fix to ulna styloid
• 1c: Distal detachment → Fix to triquetrum (rare)
• 1d: Radial detachment → Fix to radius (often with distal radius fracture)
  • May do well with Distal Radius ORIF only

Type 2 – Degenerative

• Associated with positive ulna variance and ulna impaction

Subtypes

• 2a: TFCC thinning
• 2b – 2e: Varying degrees of arthrosis affecting lunate, triquetrum, and DRUJ

Management

• Relieve the impaction → Ulna shortening osteotomy
• Debride TFCC arthroscopically
• Treat arthrosis with salvage procedures
  • Darrach Procedure
  • Suave-Kapanji Procedure