Kienbock disease

Kienbock diseaseDr. Harpreet Singh DMCH, Ludhiana

INDRODUCTIONKIENBOCK DISEAS is an isolated disorder of lunate resulting from vascular compromise to the boneAvascular necrosis/osteomalacia of lunateDr Robert Kienbock 1910He described step wise progression disease from isolated proximal lunate involvement ,to fragmentation and collapse of lunate evolving to radiocarpal involvement with degenerative changes

AETIOLOGY Exact aetiology ?But it is likely multifactorial 1. Anatomical factors 2. Interrupted vascularity 3. Traumatic insults to lunate -repeated microtrauma

Anatomical 1.Ulnar negative varience2. Three types of lunte morphalogies type 1 lunate has proximal apex type 2 and 3 more rectagular Type 1 seen in wrist with negative ulnar varience Type 1 higher rate3.Lower radial inclination All this anatomical factors seems to be results in un equal load distribution through the radiocarpal joint.

Normal ulnar variance 80% of load goes to the radius Positive ulnar variance in +2.5mm of ulnar variance 60% of load goes to radius while 40% goes though ulna leads to ulnar sided wrist pain from increased impact stress on the lunate and triquetrum associated conditions include ulnar impaction syndrome SLD TFCC tears lunotriquetral ligament tears Negative ulnar variance in -2.5mm of ulnar variance, 95% of load goes through radius and 5% of load goes through ulna associated with Kienbock's disease

Interrupted vascularityVascularity to lunate is variable3 major patterns of vascularity describedY patternI patternX pattern In I pattern there is a single vessel supplying the lunate ,which may increase risk of ostenecrosis.

In addition AVN of lunate has been linked to vascular insult caused by fracture,ligamentous collapse,primary circulatory collapse,systemic diseases and venous congestion.

Although there is no single definitive cause of kienbock disease ,a complex interplay of vascular and anatomic variation ,combined with varying degrees of microtrauma and insults contribute to its development.

CLINICAL PRESENTATIONCommonly affect men 20 to 40 yearsSymptoms can vary depending upon the stage at initial presentationPain localised to the radiolunate facet- pain is classically insidious in onsetDecreased wrist motionSwelling and decreased grip strength

Tenderness over the dorsal lunate and radiolunate facetAn effussion or bogginess overlying the radiocarpal joinMovements especially dorsiflexion is limitedAverage grip strength may decrease upto 50% of contralateral sideIn extreme case clenching of hand fails to show the normal prominence of 3rd metacarpalFINSTERSS SIGNPercussion over head of 3rd mc -tenderness

RADIOGRAPHIC IMAGINGX Ray wrist PA and lateral view Negative in early in disease processProgressively shows increased lunate density Fragmentation Collapse Proximal migration of capitate widening of proximal carpal raw scaphoid rotation degeneratine changes in radio carpal bone

MRI

MRI SCANMRI SCAN can detect early stages of disease with increased signal uptake.In patients with perilunate dislocation or ulnar impaction syndrome changes within the lunate may appears similar to the AVN ,however these changes are often focal and non progresive

CT scan CT scan characterise the lunate necrosis and trabecular destruction once collapse has occurred.

Staging

Lichtmans classification

Stage 1 Normal Xray,MRI/Bone scan+ve Stage 2 Abnormal density Stage 3a lunate collapse Stage 3b carpal collapse Stage 4 osteoarthritis

Stage INon specific intermittent wrist pain and synovitis ,which may mimic a wrist sprain.Plain x ray films are either normal or shows small linear compression fracture through lunate.There is no collapse ,sclerosis or increased radiodensity of the lunateMri shows decreased signal uptake

Stage IICharacterised by increased swelling ,varying degree of stiffness and progressive painX ray shows lunate sclerosis with or without compression fracture linesNo evidence of collapse , lunate height is maintained The remainder of the carpus remains without degenerative changes

Stage IIIAIs defined by continued sclerosis and collapse of lunateCarpal height and intercarpal alignment is preserved No scaphoid rotationXray -lunate appears widened in AP view as a result of the coronal plane collapse Scapholunate angle is preserved at -10 to 10degree

Stage IIIBCollapse of lunate and charecteristic changes of serrounding capitate and scaphoidCapitate migrate proximally and carpal height become diminishedScaphoid flexes ,rotates resulting in DISI pattern of instability

STAGE IVProgressive carpal collapse leading to radiocarpal and midcarpal degenerative changesXray joint space narrowing ,subchondral sclerosis ,degenerative cysts and osteophyte formationSymptoms have typically progressed to stiffness ,constant pain and swelling

Classification Based on MRI pattern

Schmitt and Lanz

N- Normal signal A- Marrow edema with viable and intact bony trabeculae B- Early marrow necrosis with fibro-vascular reparative tissue C- Necrotic bone marrow with collapse

TREATMENTBased on the stage at presentationUnload the lunateRevascularise the lunate Treat carpal instability and collapse with salvage procedure

Stage IConservative treatment with 3 months immobilisation is typically recommended for stage 1 deseaseThe patient should continue to be monitored and if symptoms or radiographs progress consider surgical management

Stage II or III with negative ulnar varienceGoal in this stage is generally centered towards unloading of lunte in an attempt to reduce intracarpal stress and allow revascularisationJoint leveling procedures Radial shortening osteotomies Ulnar lengthening proceduresRadial osteotomy is prefered over ulnar due to less complication

Stage II AND IIIA Ulnar neutral or positive VarianceRevascularisationOsteotomiesCor decompression

RevascularisationPrinciple Transplantation of an arteriovenous pedicle into normal and avascular bone results in new bone formationDirect revascularisation allows the potential for salvage of the lunate and possible reversal of destruction of lunate through neoangiogenesis

Sources distal radius pedicle graft with pronater teresVascularised pisiform graftFourth and fifth extensor compartment artery graftI,II or III dorasal metacarpal artery ransfer

OsteotomiesGoal of this procedure to unload the lunate in an attempt to decrease stress across radiolunate joint to allow revascularisation and prevention of disease progressionCapitate shortening osteotomies with or without capitohamate fusionRadial closed wedge osteotomyshift pressure from lunate by decreasing radioulnar inclination

Cor decompressionMetaphyseal decompression of radius and ulnaDecompression involve curettage of distal radius /ulna through small cortical windowHealing is due to local vascular response

Stage IIIBGoal in this stage Stabilisation of carpus Prevent further collapse Decrease the load across radiolunate jointProximal row carpectomyScaphotrapeziotrapezoid arthrodesisScaphocapitate arthrodesisGrafting ,arthroplasty and interposition

PRCIs procedure that excises the scaphoid ,lunate and triquetrium transfering load from the capitate directly to the lunate facet of the distal radius

STT and SC arthrodesisIs to correct fixed and rotated scaphoid and stabilise midcarpal joint ,prevent further collapse

Controversial Lunate exctionSilicon lunate prosthetic replaicement

Stage IVSalvage procedures performed

PRC If mild degenerationWRIST ARTHRODESISWRIST ARTHROPLASTYWRIST DENERVATION

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

Goal of treatment is pain relief,motion preservation ,strength maintenance and functionThere is no one procedure that consistently and reliably achieves this outcome

Goal of treatment is pain relief,motion preservation ,strength maintenance and functionThere is no one procedure that consistently and reliably achieves this outcome

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