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
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