Kienbock disease ( an overall View ) Mohamad Othman , MD 4-10 - 2012

Definition & history - KD ( or lunatomalacia ) is an idioopathic AVN of carpal lunate which may lead to collapse of the bone and arthritis in the advanced stage - first described in 1843 by Peste in cadaver dissections. - Robert Kienbock ( 1910) , a radiologist, described the x-ray changes associated w KD.

Epidemiology Natural history of KD remains unclear & un-predictable 15 and 40 years dominant wrist of men engaged in manual labor Natural history of KD remains unclear & un-predictable

Aetiology : Fault plate hypothesis: - unknown ; theories : Intrinsic ( lunate) & extrinsic factors ----- elastic deformation of trabeculae 2ry to loading ----- fault plates ---- wall off & interfere w capillary bl. Flow ----- AVN - repetitive microtrauma in the lunate at risk ( predisposed lunate ) ;

Extrinsic factors: - ulnar variance : capitate - lunate loading ulnar-negative variant wrist is common association ( Hulten, 1928). ulnar-positive variant - load type - instability

Intrinsic factors: - shape of lunate - trabecular pattern - cortical load - lunate vascular anatomy

Staging ( Modified Lichtman Classification ) Stage I: Radiographically normal lunate or with small fracture lines Stage II: Sclerosis of lunate Stage III A: Collapse or fragmentation of lunate Stage IIIB: Lunate collapse with carpal malalignment ie; proximal migration of capitate (carpal height ratio <0.54 ± 0.03) and fixed hyperflexed rotation of scaphoid( DISI)[radioscaphoid angle > 60] Stage IV: Generalized wrist arthrosis

Stage-I Stage-II Stage-III Stage-IV

Clinical picture Investigations - Complaint may precede XR changes - Varies according to stage - Pain. Tenderness ,swelling, clunk w deviation, dec ROM , weak grip Investigations - Plain XR : views….. Measurements…. Staging. - CT - Scintigraphy - MRI : earliest diagnosis : uniform low signal in T1

XR

Stahl index: Normally;B/A= 50% Carpal height ratio

CT scanning:

MRI

Differential diagnosis: - ulnar impaction synd. ( MRI) - DRUJ arthritis - Lunate Fx , intraoss ganglion, enchondroma.

Treatment Methods: Objectives : (a) precollapse (b) postcollapse Established methods: Direct vascularization Indirect vascularization ( unloading procedures): joint-levelling procedures limited carpal fusions Salvage procedures: PRC wrist arthrodesis Optional & controversial methods: - conservative Lunate excision ± replacement ( PL tendon ball , silicon, titanium) - Core decompression of distal metaphysis of R & U - Temporary ST pinning ; 3-6 mo . Stage III - External fixation - RSO in stage IIIB - RO + VBG in stage III - Wrist denervation; stage IV - Arthroscopic debridement

Treatment Algorithm Stage I: Controversial ; not completely-unload lunate. Choice in transient ischemia. After 3 mo, aggressive management as stage II Stage I, II, or IIIA with Ulnar-Negative Variance : (1) Lunate unloading by joint-leveling procedures ( RS > UL) or (2) Lunate revascularization by VBG Stage I, II, or IIIA with Ulnar-Positive or Ulnar-Neutral Variance : (1) unloading by Capitate shortening ± capitate-hamate fusion or radius ost. (2) VBG ( ± STT-pinning)

Treatment Algorithm ( cont.) Stage IIIB : -intercarpal fusions (STT and SC ) - Proximal row carpectomy ( PRC) -RSO -Lunate excision Stage IV : - conservative - Proximal row carpectomy - wrist fusion-

Radial shortening osteotomy Approach ; volar > dorsal 2-3mm ( not > 4mm ; UC impaction ) Meaphyseal / meta-diaphyseal Not decrease ROM Not in ulna positive wrist

Ulnar lengthening osteotomy Disadvantages;

Distal radius wedge osteotomy - Stage II or III w ulna-neutral or positive wrist - Lateral closing wedge osteotomy : decrease RU-inclination thus shifting press from lunate - Medial closing osteotomy or lat opening wedge o - Step- cut osteotomy

Capitate shortening osteotomy CSO + capito-hamate fusion

VBG Sources: + unloading procedure: - Base of 2nd or 3rd metacarpal Neck of 2nd meatacarpal 1,2 ICSRA - 2,3 ICSRA - 4th or 5th CA - Hori technique - Pisiform PQ + unloading procedure: - external fixator or - temporary STT-pinning or - radius osteotomy

2,3 ICSRA VBG 1,2 ICSRA VBG

4th CA VBG : retrograde flow through 5th CA from dorsal itercarpal arch

Limited carpal fusion - Objective : redistribute stresses away from lunate - Correct scaphoid malrotation 1st - SC / STT Decreases ROM Excise lunate; only if fragmented w marked synovitis

Temporary STT-pinning Triscaphe (STT) fusion SC- fusion

Prox raw carpectomy Total wrist fusion

Incisions for wrist denervation Core decompression of distal metaphysis of R & U

والسلام عليكم ورحمة الله وبركاته وشكرا THANK YOU والسلام عليكم ورحمة الله وبركاته