May 30, 2024

Keinbock’s disease is avascular necrosis of lunate/ lunatomalacia which is one of the causes of wrist pain.

Keinbock’s disease

Etiology of Keinbock’s disease

Unclear

Pathogenesis

Reduction of blood supply to lunate is a cause of Avascular necrosis of lunate which can be caused by

  • Post-traumatic
  • Secondary to Systemic disease
    • SLE
    • Scleroderma
    • Sickle cell disease
    • Steroid intake
    • Microtrauma due to vibrating tools use
  • Ulna Variance (-) will provide more stress on lunate
  • Decrease radial slope
  • Higher interosseous pressure in lunate (in extension) compared to other bone leads

Clinical Features

Young males with pain in wrist on activity

Tenderness in the dorsum of lunate

Central synovitis may be visible

Reduction in joint range of motion

When there is the collapse of lunate, subsidence of 3rd metacarpal is seen in making a fist

Percussion of 3rd metacarpal head produces tenderness (FINSTERER’S SIGN)

Reduced grip strength

Radiological Classifications

Lichtman’s Classification

StagesRadiological features
INormal X-ray/ Linear fractures
IIEarly collapse on the radial side, one or more fractures, Sclerosis
IIILunate collapse is seen with
IIIANormal carpal alignment and height
IIIBScaphoid rotation (ring sign), Carpal height decrease, Capitate migrate proximally
IVSevere lunate collapse, Intraarticular degeneration at mid-carpal and radiocarpal joint
Lichtman’s classification

Other investigations

Bone Scan: Reduce uptake in lunate

MRI: Main stay of diagnosis (Detects in stage I)

Diagnostic arthroscopy: Articular changes appear

Treatment Options for Keinbock’s disease

Treatment is based on Lichtman’s staging;

Stage I

  • Immobilization for 3 months

Stage II/ Stage IIIA

(Neutral variance/ (-) ulna variance)

  • Radial shortening osteotomy
  • Capitate shortening
  • Ulna lengthening

Stage II/ Stage IIIA

((+) Ulna variance)

  • Revascularization(Core decompression or transplantation of arterio-venous pedicle in normal avascular bone) and scapho-capitate pinning or External fixation
  • Radial wedge osteotomy
  • Capitate shortening
  • Joint leveling procedures

Stage IIIB

  • STT fusion (Scapulocapitate fusion) + excision of lunate and tendon anchovy

Stage IV

  • Total wrist fusion
  • Proximal row carpectomy
  • Wrist denervation procedure

Joint leveling procedure for Keinbock’s disease

Radial shortening + Ulna lengthening will reduce force across the radio-lunate joint by 45%

But shortening of > 4 mm, affects DRUJ so, maximum shortening up to 3 mm is done

Healing potential is better with radial shortening than the ulna

Vascularized Bone Graft

Pronator quadratus pedicle graft

Vascularized pisiform, metacarpal artery based bone graft etc

Limited Wrist Fusion

  • Scaphoid trapezial trapezoid (STT)
  • Scapho-capitate fusion
  • Proximal Row carpectomy
  • Total wrist fusion (TWF)
  • Metaphyseal core decompression of radius and ulna
  • Prosthetic lunate replacement