Kienbock’s disease

Courtesy: Prof Abhijeet Wahegaonkar, Sancehti Hospital, Pune, India

Introduction
• Robert Kienbock- radiologist. Described xray changes associated with lunatomalacia.
• an isolated disorder of the carpal lunate arising out of vascular compromise
• multifactorial pathogenesis- influenced by genetic, anatomic, mechanical and metabolic factors.

Historical perspectives

• first described by Peste in 1843 who noted a collapsed lunate in cadaver dissection
• Robert Kienbock- radiologist. Described Xray changes associated with
  Kienböck’s disease

Etiology

• etiology is still undefined so various factors have been proposed
• aberrant blood supply to lunate: problems with arteries[single dominant nutrient arterial supply for lunate (20%patients)
• poorly organized intraosseous circulation —“i”pattern of anastomosis
• ulnar variance (radioulnar index) = distance between distal point of ulna on radial side and the distal point of radius on ulnar side. Normal is ±2, -2 means ulna is 2 mm shorter than radius.
• lunate geometry
• mechanical injury

Diagnosis:

• symptoms can vary depending upon the stage at initial presentation.
• pain localised to the radiolunate facet pain is classically insidious in onset
• pain and stiffness in the dominant wrist
• decreased grip strength
  hyperextension injury

Radiographs

X-ray imaging during stage 1 of the disease will show an apparently normal lunate bone, later sclerosis, fracture, fragmentation and collapse are seen.

Bone scan
o nonspecific
o does not rule out early AVN

Trispiral tomography
more accurate staging than x-ray alone
• does not rule out early AVN

CT scan
• provides useful detail of fracture fragments

Mri
• sensitive, specific

• magnetic resonance imaging can help to assess the blood supply to the lunate.
• The gadolinium-infused mri has been used to find the vascular patterns
  abnormal signal in 50% of lunate

Staging

• Lichtman modification of Stähl’s classification
  • stage 1-4
  • modified by Amadio
• stage 1- no visible changes on radiograph; changes seen on mri.
• stage 2- sclerosis of lunate
• stage 3a- fragmentation of lunate
• stage 3b- fixed rotation of scaphoid
• stage 4- degeneration of adjacent intercarpal joints

Treatment

• based on the stage at presentation
• unload the lunate
• revascularise the lunate
• treat carpal instability and collapse with salvage procedure

Stage 1
• conservative treatment with 3 months immobilisation is typically recommended for stage 1 disease

• the patient should continue to be monitored and if symptoms or radiographs progress consider surgical management.

Stage II or III with negative ulnar variance

• goal in this stage is generally centered towards unloading of lunate is an attempt to reduce
  intracarpal stress and allow revascularization.

Joint levelling procedures-
• radial shortening osteotomies
• ulnar lengthening procedures

Radial osteotomy is preferred over ulnar due to less complication

Stage II and 3a ulnar neutral or positive variance

• revascularisation
• osteotomies
• core decompression

Stage 3b
o goal in this stage
o stabilization of carpus
o prevent further collapse

Decrease the load across radiolunate joint

• proximal row carpectomy
  • scaphotrapeziotrapezoid arthrodesis
  • scaphocapitate arthrodesis
  • grafting ,arthroplasty and interposition

Stage iv
• salvage procedures performed.
• wrist arthrodesis
• wrist arthroplasty
• wrist denervation.

Summary

• Kienbock disease is defined by AVN of lunate, with a predictable pattern of lunate collapse .carpal changes, and degeneration resulting from an apparent combination of vascular, anatomical and traumatic insults