Kienbock's disease Flashcards
Kienbock’s disease
first described 1843 by Peste - than later on Robert Kienböck a radiologist described the x-ray changes
children - non-surgical treatment
natural histoy is unknown
AVN of other carpal bones is rare
etiology
no consensus about is
lunate fractures who had failed may lead to AVN (avascular necrosis) of the lunate
most likely it is multifactorial
primary circulary problems, traumatic interference, poor circulation, ligament injury with collapse, fractures with secondary vascular impairment
associated with:
scleroderma, sickle cell anemia, SLE, corticosteroid use
many patient are ulnar-negative - but no statiscally results for this opinion
ulnar-negative patients - type I lunate with a proximal crest or apex
ulnar-normal patients - type II or III lunate with a rectangle or square form
trabecular pattern of type I lunate is the most weakest - unequal distribution of axial load because of the bony form - more pressure to the lunate with dorsal radiocarpal extension
- distal radial form maybe responsible for AVN - lower radial inclination - radial slope AP has effect to the force transmitted to the lunate
Viegas lunate type
Viegas type 1 lunate occurs in 35% has no distal medial facet
flexion through the midcarpal joint, coronal fractures are more common - type 1 lunates predictable for Kienbock
Viegas type 2 lunate occurs in 65% distal medial facet to the hamate
flexion through the radiocarpal joint, protection against DISI position and protection for scaphoid flexion
compartment syndrome of bone
great pressure and repetitive loading leads to an insult of the bone - leads to a compartment syndrome with ischemia and bone necrosis and phagozytosis of necrotic tissue
vascular factors
most comes from the palmar aspect, 5 named vessels from dorsal and volar supply the lunate - the subchondral subarticular venous plexus can easily be damaged with leads to ischemia and bone necrosis
at-risk patient
at-risk lunate
at-risk patient:
young, active male, manual laborer
at-risk lunate:
morphological structures susceptibility for Kienböck
Viegas type I (more radiocarpal motion with loading)
Zapico type I (lunate loads on the radial aspect)
flattened radius - more radial loading
negative ulnar variance - increases radiolunate contact forces
capitate often affects like a nutcracker in the coronal plane
if the lunate is off loaded process can be reversible - if it progresses comminution occurs
two types of Kienböck -
global or generalized ischemia occurs from a single arterial supply - better prognosis
localized obstruction can cause stress fractures and localized hypertension - this lead to comminution, medullary bone abrasion and further lunate collapse
affect to the wrist
- central column deformation, collapse and proximal row instability
- degenerative changes at the radiocarpal joint
- degenerative changes at the midcarpal joint and Kienböck’s disease advanced collapse (KDAC)
clinic and radiographics
dull pain over the dorsal lunate mostly young male - maybe with some hyperextension injuries in history - pain aggraved with activity - decreased grip strength - pain, weakness, instability and stiffness - duration of symptoms before diagnosis is about 1 to 2 years - patient normally between 20 and 40y
standard radiographics:
increased bone density - early sign of AVN
MRI most sensitive - the entire lunate must show signal loss - not only the ulnar border - ulnar impaction of the lunate!!!
4 pathoanatomical phases of the lunate
- edema of lunate due to ischemia - T2 up, T1 down
- cellular necrosis - T2 down, T1 down
- repair phase - further signal reduction in T1 and T2
- bone remodelling - Osteoblasts and Osteoclasts predominate - further signal reduction T1 and T2
better ceMRI with gadolinium (Schmitt classification
- a - normal - homogenous enhancement
- b - ischemic - homogenous enhancement of the entire proximal zone - maintained perfusion
- c - partially necrotic - inhomogeneous contrast with 3 different perfusion zones - enhancement of middle zone as hypervascular “reperative” zone
- d - necrotic (viability lost) - generalized signal loss
SPECT maybe helpful
arthroscopic classification - BAIN and BEGG classification
0 - normal surface
1 - nonfunctional surface - proximal lunate
2a - nonfunctional surface - proximal lunate - lunate fossa
2b - nonfuntional surface - proximal and distal lunate
3 - nonfunctional surface - proximal and distal lunate, fossa lunate
4 - nonfuntional surface - proximal and distal lunate, fossa lunate and capitate surface
lunate sclerosis
progressive loss of lunate height
fragmentation of the lunate
progressive loss of carpal height - capitate migrates proximally
degenerative changes of the scaphoid or carpal collapse
Staging:
by Lichtman
I - radiographics generally normal - maybe a linear fracture - MRI demonstrates diffuse T1 signal decrease in lunate - bone scan is positive
II - sclerosis of lunate - multiple fracture lines - no collapse of the lunate
IIIA - lunate collapses - carpal height have been maintained - radioscaphoide angle - <60°
IIIB - lunate collapses - capitate migrated proximally - radioscaphoide angle - >60°
IIIC - lunate collapses - coronal fracture - chronic disease
IV - as IIIB with carpal osteoarthritis
Carpal height ratio -
height of the carpus (CH - carpal height) divided through the height of the 3rd metacarpal (MH) - normal is 0,51 to 0,57
IIIB - best predictor - in literature - a radioscaphoid angle greater than 60°
treatment
stadium I, II and IIIA with ulnar-negative configuration
three main groups of treatment
procedures…
- to unload the lunate
- to promote revascularization
- as salvage procedures in stadium IV
non-operatively patients get decreased motion, grip strength, bad DASH score (study by Keith)
Stage I, II and IIIA with ulnar-negative variance
symptomatic patient with no instability or arthritis - than joint-leveling procedure
- radial shortening osteotomy - goal ulnar-neutral or minimal ulnar-positive (this should not be done with patients who are ulnar-positive or neutral) maybe development of an ulnar-impaction syndrome -
study showed that 90% of lunate strain reduction comes from a shortening from 2mm - 3mm or more give disadvantages for the DRUG and no more less load
87% decreased pain - 32% better wrist motion
ulnar lengthening possible (Linscheid study), but with the risk of an ulno-carpal impingement
vascularized bone grafting
for stage I, II or IIIA disease - many vessels on the dorsal of the hand - dorsum of the carpal arch, dorsal radiocarpal arch, dorsal supraretinacular arch
these are the 1,2 and 2,3 intercompartment supraretinacular arteries (1,2 ICSRA and 2,3 ICSRA)
1,2 ICSRA orignates from the radial artery 5cm proximal to the radiocarpal joint - short pedicle and a short arc of rotation - maybe used for the scaphoid non union procedure
2,3 ICSRA proximal origin of the anterior interosseus artery - lister’s tubercule - anastomoses with the dorsal intercarpal arch - it is easily to harvest and has a good arc of rotation
most useful vessels are the arteries of the 4. and 5. extensor compartment - best is the 5. extensor compartement artery - lays radial in the compartement - harvest a bone graft 11mm proximal to the radius ridge - mobilize the 5. artery and than look for the interosseus ant. artery - this is divided proximal with Y-vessel for 4. and 5. artery - so the pedicle is long with a good arc of rotation
other procedures:
2,3 ICSAR artery - or the dorsal second intermittent carpal artery is put into the bone without bone graft (described by Hori)
treatment II
stage I, II and IIIA with ulnar-neutral or positive
capitate shortening with capitate-hamate fusion - over dorsal approach - decompress the lunate from the capitate - this can be done in total or partial - in the same time a arthrodesis with the hamate is done - hold with k-wires or with headless screws
maybe done - radial osteotomy which is technically demanding - wedge osteotomy on the volar radius with the base radially to decrease the radial inclination
treatment III
stage IIIB and IV
only salvage procedures - various intercarpal fusions has been described - including STT and scaphocapitate arthrodesis - scaphocapitate arthrodesis easier to perform
other authors use proximal row carpectomy and show less pain in ther patients group - although without statiscally significance - they prefer the proximal row carpectomy over STT-Arthrodesis
pylocarbon prosthesis is possible especially with younger patients
stage IV
maybe proximal row carpectomy, if the lunate fossa is preserved - instead than wrist fusion - normally the funcition and the motion is limited in this stadium
treatment IV
based on the Lichtman, Schmitt and Bain and Begg classification
A - patient’s age
A1 < 15y - non-operatively
A2 - 16-20y - non-operative first - consider unloading procedure
A3 - >70y - non-operative first - consider synovectomy
B - stage of lunate
B1 - lunate intact (Lichtman 0,1,2 - Schmitt A - Bain 0)
protect and unload the lunate
orthosis or cast first (2-3month)
radial shortening (ulnar negative) - capitate shortening (ulnar positive) - radial epiphysiodesis
alternatives (lunate compression, vascularized bone graft, lunate forage)
B2 - lunate compromised (Lichtman IIIA, Schmitt B, Bain 1)
lunate reconstruction - MFT (osteochondral flap of the medial femur trochlea), PRC (RSL-Fusion), SC or STT fusion
B3 - lunate not reconstructable (Lichtman IIIB,C, Schmitt C, Bain 2b)
Lunate replacement, capitate lengthening, PRC, SC fusion
C - state of the wrist
C1 - carpal instability with intact articulations - stabilize
typical scaphoid flexion with RSA >60° (Lichtman IIIB) - stabilize radial column (SC fusion)
C2 - localized carpal degeneration - recontruct
C2a - radiolunate articulation compromised (Lichtman IIIA, Bain 2a)
Bypass - SC-fusion, reconstruct MFT, replacement, fuse RSL fusion
C2b - radioscaphoid articulation compromised
PCR - if lunate fossa intact, RSL fusion if lunate fossa degenerative
C3 - KDAC - salvage - advanced wrist disease (Lichtman IV, Bain 4)
wrist fusion or arthroplasty
equilibrium of loading
- radial shortening osteotomy
- radial wedge osteotomy (greater surface of lunate and radius)
- capitate shortening (decreased load to lunate)
- STT and scaphocapitate fusion lead to radial column loading bypassing the diseased, fragmented lunate
