Avascular Necrosis of Lunate | Progressive Wrist Arthritis | Ulnar Variance Key
Lichtman Staging (Modified)
Critical Must-Knows
- Negative Ulnar Variance: Present in 78% - ulna shorter than radius increases lunate loading
- Lichtman Stage IIIB: Scaphoid rotation = critical prognostic divider - salvage surgery required
- MRI Gold Standard: Detects Stage I disease before X-ray changes appear
- Joint Leveling: Radial shortening or ulnar lengthening for Stage II-IIIA with negative variance
- PRC: Proximal row carpectomy - motion-preserving salvage for Stage IIIB-IV without arthritis
Clinical Pearls
- "Negative ulnar variance = lunate takes excessive load
- "Stage IIIB (scaphoid rotation) = point of no return
- "MRI shows bone marrow edema before X-ray changes
- "Radial shortening decreases lunate loading by 45%
Clinical Imaging
Imaging Gallery
Critical Kienböck's Disease Exam Points
Staging is Treatment
Lichtman Stage IIIB is the critical divider. Scaphoid rotation indicates lunate collapse severe enough to destabilize the carpus. Stages I-IIIA may benefit from joint leveling; IIIB-IV require salvage procedures.
Ulnar Variance Matters
Negative ulnar variance in 78% of cases. Ulna 2-4mm shorter than radius increases lunate loading. Radial shortening osteotomy decreases lunate force by 45%.
MRI for Early Diagnosis
Stage I disease is MRI-only. Bone marrow edema and low T1 signal precede X-ray sclerosis by months. Early detection may allow non-operative treatment.
Salvage Options
PRC vs Fusion trade-offs. Proximal row carpectomy preserves 50% motion but requires intact capitolunate articulation. Fusion eliminates motion but relieves pain reliably.
Quick Decision Guide
| Stage | X-ray Findings | Treatment | Key Pearl |
|---|---|---|---|
| I | Normal X-ray, MRI positive | Immobilization 3-6 months | May arrest progression if caught early |
| II | Sclerosis, no collapse | Radial shortening or revascularization | Joint leveling decreases lunate loading |
| IIIA | Collapse, NO scaphoid rotation | Consider joint leveling if lunate viable | Last chance for joint-preserving surgery |
| IIIB | Collapse WITH scaphoid rotation | PRC or limited fusion | Scaphoid rotation = carpal instability |
| IV | Generalized arthritis | Total wrist fusion or arthroplasty | End-stage disease |
I See Carpal ArthritisLichtman Staging Progression
| I | Intact Normal X-ray, MRI shows AVN |
| S | Sclerosis Stage II - density increased on X-ray |
| C | Collapse Stage IIIA/B - lunate height loss |
| A | Arthritis Stage IV - degenerative changes throughout wrist |
| I | Intact Normal X-ray, MRI shows AVN | C | Collapse Stage IIIA/B - lunate height loss |
| S | Sclerosis Stage II - density increased on X-ray | A | Arthritis Stage IV - degenerative changes throughout wrist |
Hook:I See Carpal Arthritis = the natural progression of untreated Kienböck's disease from invisible to end-stage!
LUNATERisk Factors for Kienböck's Disease
| L | Loading (repetitive) Repetitive wrist use, manual labor |
| U | Ulnar variance (negative) Short ulna = excess lunate load |
| N | Necrosis risk anatomy Single vessel supply to lunate |
| A | Autoimmune/steroids Corticosteroids, SLE, vasculitis |
| T | Trauma history Prior wrist fracture or injury |
| E | Endocrine disorders Hypothyroidism, diabetes |
| L | Loading (repetitive) Repetitive wrist use, manual labor | N | Necrosis risk anatomy Single vessel supply to lunate | T | Trauma history Prior wrist fracture or injury |
| U | Ulnar variance (negative) Short ulna = excess lunate load | A | Autoimmune/steroids Corticosteroids, SLE, vasculitis | E | Endocrine disorders Hypothyroidism, diabetes |
Hook:LUNATE = the bone that dies! Remember the risk factors that predispose to AVN.
PRC-FSalvage Surgery Options
| P | Proximal row carpectomy Remove scaphoid-lunate-triquetrum, preserve motion |
| R | Radiolunate fusion Fuse radius to lunate, preserve some motion |
| C | Capitolunate fusion Fuse capitate to lunate |
| F | Four-corner fusion Fuse capitate-hamate-lunate-triquetrum, excise scaphoid |
| P | Proximal row carpectomy Remove scaphoid-lunate-triquetrum, preserve motion | C | Capitolunate fusion Fuse capitate to lunate |
| R | Radiolunate fusion Fuse radius to lunate, preserve some motion | F | Four-corner fusion Fuse capitate-hamate-lunate-triquetrum, excise scaphoid |
Hook:PRC-F = Proximal Row and Carpal Fusions - the salvage spectrum from motion-preserving to stable fusion!
Overview and Epidemiology
Why Kienböck's Matters
Kienböck's disease is a rare but disabling condition affecting young, active patients. Understanding staging and treatment algorithms is essential for hand surgery exams and clinical practice.
Kienböck's Disease is avascular necrosis (AVN) of the lunate bone, leading to progressive collapse, carpal instability, and wrist arthritis.
Demographics
- Age: 20-40 years (peak incidence)
- Gender: Male predominance 2:1
- Occupation: Manual laborers, athletes
- Bilateral: Rare (less than 5%)
Typically affects dominant hand of young workers.
Natural History
- Early (I-II): May stabilize with treatment
- Mid (IIIA): Progressive collapse likely
- Advanced (IIIB-IV): Irreversible arthritis
- Timeline: Years to decades of progression
Early diagnosis is critical to prevent collapse.
Pathophysiology and Etiology
Lunate Vascular Anatomy
The lunate has tenuous blood supply with two main patterns: Type I (Y-pattern from radial and ulnar arteries, 80%) and Type II (single vessel, 20%). Interruption leads to AVN, particularly in Type II anatomy.
Etiology is multifactorial:
Risk Factors
-
Negative Ulnar Variance (78% of cases)
- Ulna 2-4mm shorter than radius
- Increases lunate loading by transmitting more force
- Present in normal population at only 23%
-
Repetitive Microtrauma
- Manual labor, jackhammer use
- Gymnastics, racquet sports
- Cumulative stress to lunate
-
Vascular Anatomy
- Single vessel supply (Type II) at higher risk
- Intraosseous anastomoses limited
- Watershed areas vulnerable
-
Systemic Associations
- Corticosteroid use
- Systemic lupus erythematosus
- Gout, sickle cell disease
- Hypothyroidism
Pathophysiology Cascade:
- Vascular insult or repetitive trauma
- Ischemia and bone marrow edema
- Osteocyte death and sclerosis
- Structural collapse of lunate
- Scaphoid rotation and carpal instability
- Progressive radiocarpal and midcarpal arthritis
Biomechanics of Negative Variance
Negative ulnar variance increases lunate loading. In a neutral wrist, 60% of axial load transmits through radius and 40% through ulna. With 2mm negative variance, lunate bears 95% of radiocarpal load.
Radial shortening osteotomy redistributes load to ulna.
Collapse Mechanism
AVN weakens subchondral bone. Repeated loading causes microfractures, progressive height loss, and eventual fragmentation. Once collapse begins (Stage III), progression is difficult to arrest.
Early intervention aims to prevent collapse.
Classification Systems
Lichtman Classification (Modified 2010)
The gold standard staging system, based on radiographic appearance and treatment implications.
| Stage | Radiographic Findings | Lunate Status | Treatment Approach |
|---|---|---|---|
| I | Normal X-ray; MRI shows AVN | Structurally intact | Immobilization, observation |
| II | Sclerosis on X-ray | Intact, no collapse | Joint leveling, revascularization |
| IIIA | Collapse, no scaphoid rotation | Collapsed, some viability | Joint leveling if viable, or PRC |
| IIIB | Collapse WITH scaphoid rotation | Collapsed, carpal instability | PRC, partial fusion |
| IV | Generalized carpal arthritis | Fragmented, arthritic | Total wrist fusion or arthroplasty |
Stage IIIB is the critical prognostic divider: scaphoid rotation indicates fixed carpal collapse beyond salvage with joint-preserving techniques.
Staging determines treatment strategy and prognosis.
Clinical Assessment
History
- Pain: Dorsal wrist pain, worse with activity
- Weakness: Grip strength reduced 30-50%
- Stiffness: Progressive loss of motion
- Occupation: Manual labor, repetitive wrist use
- Trauma: History of wrist injury in 30%
- Dominant hand: Usually affected
Insidious onset over months is typical.
Examination
- Inspection: Dorsal swelling over lunate
- Palpation: Tenderness over lunate fossa
- ROM: Decreased flexion and extension (50% of normal)
- Strength: Grip weakness (30-50% reduction)
- Provocative: Pain with axial loading of 3rd metacarpal
- Watson test: May be positive (scaphoid instability)
Physical findings are non-specific; imaging confirms diagnosis.
Clinical Findings by Stage
| Stage | Pain | Motion Loss | Grip Strength |
|---|---|---|---|
| I-II | Mild, activity-related | Minimal (10-20%) | Near normal |
| IIIA | Moderate, constant | Moderate (30-50%) | Reduced 30-40% |
| IIIB-IV | Severe, rest pain | Severe (over 50%) | Reduced over 50% |
Differential Diagnosis
Dorsal/central wrist pain in a young adult has several mimics. MRI is the single best discriminator: AVN of the lunate shows diffuse low T1 marrow signal, whereas the alternatives below have characteristic alternative patterns.
Differential Diagnosis of Central Wrist Pain
| Condition | Typical features | Key imaging discriminator | Distinguishing point from Kienböck's |
|---|---|---|---|
| Kienböck's disease | Insidious dorsal pain, young manual worker, grip loss | Diffuse low T1 signal throughout lunate; later collapse | AVN is global to the lunate, not focal |
| Scapholunate ligament injury | Trauma history, dorsal SL tenderness, positive Watson | SL gap (Terry-Thomas sign), DISI; lunate marrow normal | Lunate signal is normal; instability is ligamentous |
| TFCC tear / ulnocarpal impaction | Ulnar-sided pain, positive ulnar variance, click | Ulnar-positive variance, ulnar lunate/triquetral cysts | Pain is ulnar-sided; usually ulnar-POSITIVE variance |
| Ulnar impaction syndrome | Ulnar pain on loading/grip | Subchondral cysts at ulnar lunate, positive variance | Opposite ulnar variance to classic Kienböck's |
| Occult/lunate fracture | Acute trauma, focal tenderness | Discrete fracture line; focal not diffuse marrow change | Single fracture line rather than diffuse AVN |
| Ulnar-sided ganglion / carpal boss | Localised swelling, dorsal lump | Cyst or osteophyte; lunate normal | Structural lesion, normal lunate marrow |
Controversies and Areas of Uncertainty
Unresolved Questions Examiners Probe
Kienböck's disease has no Level I evidence and no consensus guideline. A strong candidate acknowledges the uncertainty rather than overstating any single procedure.
Does any procedure alter natural history?
The Shin et al systematic review (JBJS Am 2018) found radial osteotomy did not slow Lichtman-stage progression versus nonoperative care, despite better pain and motion. Whether we are modifying disease or only managing symptoms remains genuinely unsettled.
Etiology: cause or association?
Negative ulnar variance, single-vessel supply and repetitive load are predisposing factors, not proven causes. Modern reviews reframe historic "causal" factors as markers of a pre-existing vulnerable lunate.
Stage I management
No reliable way to predict which MRI-only cases progress. Choice between immobilization with surveillance and early unloading/revascularization is shared decision-making, not protocol.
Non-negative ulnar variance
When variance is neutral or positive, radial shortening is biomechanically wrong. Capitate shortening osteotomy is the rational alternative (Motaghi et al 2025), but evidence is Level IV only.
PRC vs four-corner fusion
Long-term outcomes are comparable (Chim & Moran). PRC is technically simpler with no nonunion risk; four-corner fusion may suit very heavy demand. No randomised comparison exists.
Role of free vascularized grafts
Medial femoral condyle free flap can reconstruct a compromised but salvageable lunate, but is confined to microsurgical units and lacks comparative trials against simpler unloading.
Investigations
Investigation Protocol
PA, lateral, and clenched-fist views. Look for: lunate sclerosis (Stage II), collapse with decreased height (Stage III), scaphoid rotation on lateral (IIIB), carpal arthritis (IV). Measure ulnar variance on neutral rotation PA view.
T1 and T2 sequences. T1 shows low signal (bone marrow replacement), T2 shows variable signal depending on stage. Detects Stage I disease before X-ray changes. Also assesses lunate viability and cartilage integrity.
For surgical planning. Defines extent of collapse, fracture lines, and articular involvement. Useful before salvage procedures to assess capitate head (for PRC) or plan fusion surfaces.
Rarely used. Increased uptake in lunate. Less specific than MRI. Historical interest; MRI has replaced it.
Key Radiographic Measurements
| Measurement | Technique | Normal Value | Kienböck's Finding |
|---|---|---|---|
| Ulnar variance | PA view, neutral rotation, difference in radial-ulnar heights | 0 to +2mm | Negative variance in 78% |
| Carpal height ratio | Lateral view, capitate to radius distance / lunate to 3rd MC length | 0.54 ± 0.03 | Decreased in Stage III+ |
| Scapholunate angle | Lateral view, angle between scaphoid and lunate | 30-60 degrees | Over 60° in Stage IIIB (DISI) |
Radiographic Stages
Stage I: Normal X-ray (diagnosis requires MRI)
Stage II: Increased density (sclerosis) of lunate, normal shape and height
Stage IIIA: Lunate collapse with height loss, scapholunate angle normal (less than 60°)
Stage IIIB: Lunate collapse PLUS scaphoid rotation - scapholunate angle over 60° (DISI pattern)
Stage IV: Generalized carpal arthritis - radiocarpal, midcarpal, or both
Management Algorithm
Conservative Management
Indications: Stage I disease, patient refuses surgery, medical comorbidities
Conservative Treatment Steps
Short-arm cast or splint for 3-6 months. Aim is to unload lunate and allow revascularization. Success rate 30-50% in Stage I. Monitor with serial MRI every 3-4 months.
Avoid heavy manual work. Reduce impact loading. Ergonomic assessment. Consider job modification or retraining.
Bisphosphonates (experimental). Limited evidence. Iloprost (prostacyclin analog) may improve vascularity. NSAIDs for pain control.
Outcomes: Conservative treatment rarely effective beyond Stage I. Progression common without surgical intervention.
Conservative management is temporizing in most cases.
Treatment Algorithm by Lichtman Stage
| Stage | Preferred Treatment | Alternative | Outcomes |
|---|---|---|---|
| I | Immobilization 3-6 months | Observation | 50% arrest progression |
| II | Radial shortening (if -UV) | Revascularization | 60-80% pain relief |
| IIIA | Joint leveling or revascularization | Consider PRC | Variable, 40-70% success |
| IIIB | PRC or four-corner fusion | STT fusion | 80% pain relief, limited motion |
| IV | Total wrist fusion | Wrist arthroplasty (selected) | Excellent pain relief, no motion |
Surgical Technique
Radial Shortening Osteotomy
Surgical Steps
Supine, arm table, tourniquet. Volar approach to distal radius: longitudinal incision between FCR and radial artery. Protect superficial radial nerve branches.
Retract FCR ulnarly, radial artery radially. Expose pronator quadratus and incise longitudinally. Subperiosteal elevation of distal radius.
Mark osteotomy 2-3cm proximal to radial articular surface. Perform transverse osteotomy with oscillating saw. Remove 2-4mm bone wedge (based on pre-op ulnar variance measurement). Shorten radius.
Compress osteotomy and apply dorsal locking plate. Ensure stable fixation. Check DRUJ stability and rotation.
Repair pronator quadratus (protects plate). Skin closure, splint in neutral.
Technical Pearls:
- Pre-op planning: measure exact ulnar variance and plan shortening amount
- Avoid excessive shortening (over 4mm) - causes DRUJ symptoms
- Compress osteotomy fully to minimize nonunion risk
- Use locking plate for secure fixation in osteopenic bone
Pitfalls:
- Inadequate shortening - fails to unload lunate
- Excessive shortening - DRUJ pain and stiffness
- Nonunion if inadequate fixation or bone contact
Radial shortening decreases lunate loading biomechanically.
Complications
Complications by Treatment
| Treatment | Early Complications | Late Complications | Management |
|---|---|---|---|
| Radial shortening | Infection, CRPS | Nonunion (5%), DRUJ pain | Bone graft, revision fixation |
| Revascularization | Pedicle injury, hematoma | Graft failure, lunate collapse | Consider salvage procedure |
| PRC | Stiffness, CRPS | Capitate-radius arthritis (20% at 10 years) | Convert to fusion |
| Four-corner fusion | Nonunion (5-10%), hardware irritation | Adjacent joint arthritis | Hardware removal, convert to total fusion |
General Complications
Progression of Disease (untreated):
- Stage I to IV over 3-10 years
- Inevitable without intervention in most cases
- Collapse and arthritis are endpoint
Complex Regional Pain Syndrome (CRPS):
- Occurs after 2-5% of wrist surgeries
- Risk factors: female, prolonged immobilization
- Prevention: early motion, vitamin C supplementation
- Management: multidisciplinary pain team
Stiffness:
- Common after any wrist surgery
- Worse with prolonged immobilization
- Prevention: early therapy, limit casting to 6 weeks max
Postoperative Care
Postoperative Protocol by Procedure
Short-arm splint. Finger and elbow ROM immediately. X-ray at 2, 6 weeks to assess union.
Wean splint, begin wrist ROM. Therapy for strengthening. Full activities at 12 weeks if healed.
Short-arm cast. Strict immobilization to allow graft incorporation. No motion.
Removable splint, begin ROM. Protected strengthening. Full activities 12-16 weeks.
Bulky dressing. Finger ROM immediately. Wound check, transition to removable splint at 2 weeks.
Removable splint, begin wrist ROM at week 3. Early motion prevents stiffness. Strengthen grip.
Wean splint, progressive strengthening. Return to normal activities by 3 months.
Return to Work:
- Desk work: 2-4 weeks (depending on procedure)
- Light manual work: 8-12 weeks
- Heavy manual labor: 12-16 weeks or job modification
Long-term Monitoring:
- Annual X-rays for first 3 years to detect progression
- MRI if symptoms worsen or new pain
- Salvage planning if joint-preserving procedure fails
Outcomes and Prognosis
Outcomes by Treatment
| Treatment | Pain Relief | Motion Preservation | Durability |
|---|---|---|---|
| Conservative (Stage I) | 50% improvement | Maintained if stable | Variable, monitoring needed |
| Radial shortening (Stage II) | 60-80% good outcome | Maintained | Good 5-10 years |
| Revascularization (Stage II-IIIA) | 40-70% improvement | Maintained if successful | Variable, graft-dependent |
| PRC (Stage IIIB) | 80% good pain relief | 50% motion vs normal | Durable 10+ years |
| Four-corner fusion (Stage IIIB-IV) | 85% pain relief | 40-50% motion | Good 5-10 years |
| Total fusion (Stage IV) | 95% pain relief | 0% motion | Excellent long-term |
Prognostic Factors:
| Factor | Better Outcome | Worse Outcome |
|---|---|---|
| Stage at diagnosis | I-II | IIIB-IV |
| Age | Under 30 | Over 50 |
| Occupation | Sedentary | Heavy manual labor |
| Ulnar variance | Negative (correctable) | Neutral/positive |
Natural History (Untreated):
- Stage I: 50% progress to Stage II within 2 years
- Stage II: 80% progress to Stage III within 3-5 years
- Stage IIIB: 100% progress to Stage IV without treatment
- Timeline: Variable, 3-15 years from onset to end-stage
Early diagnosis and intervention improve outcomes substantially.
Evidence Base
- Reviews the four-stage radiographic Lichtman classification and its treatment algorithm
- Stage IIIB (fixed scaphoid rotation) marks the transition from joint-preserving to salvage surgery
- Emphasises that a reproducible staging system underpins surgical decision-making
- Anticipates perfusion- and cartilage-based classifications as adjuncts to plain radiographs
- Arthroscopic classification grading the number of non-functional lunate and adjacent articular surfaces
- Disease typically begins at the proximal lunate surface before involving the radial lunate facet
- Procedure is matched to grade: synovectomy/radial shortening, PRC, radioscapholunate fusion, or wrist fusion
- Adds intra-articular cartilage assessment that plain radiographs cannot provide
- Integrates the Lichtman (osseous), Schmitt (perfusion/viability) and Bain (cartilage) classifications into one algorithm
- Frames management around 'intact', 'compromised lunate', 'compromised wrist' and unreconstructable end-stage
- Compromised lunate may be reconstructed with medial femoral condyle graft or proximal row carpectomy
- Stresses that patient factors (age, demand, comorbidity) and surgeon factors modify the final decision
- 17 long-term studies (mean follow-up at least 10 years): 12 radial osteotomy, 5 nonoperative
- Radial osteotomy did NOT slow Lichtman-stage progression compared with nonoperative care
- More-than-moderate pain at final follow-up: 5.7% after radial osteotomy vs 23.2% nonoperative
- Total wrist arc was greater after radial osteotomy (107° vs 89°)
- 144 consecutive proximal row carpectomies, mean follow-up 13.4 years
- Good pain relief with preservation (not improvement) of motion; 12% required revision
- A preoperative diagnosis of Kienböck's disease was associated with improved pain, function and survival
- Radiocapitate arthrosis developed in 45% but did not correlate with clinical outcome or revision
- Six studies, 147 patients with at least 10-year follow-up after proximal row carpectomy
- No significant change between pre- and long-term postoperative motion; mean grip 68.4% of contralateral
- Outcomes comparable to four-corner arthrodesis; 14.3% failure rate requiring re-operation
- Heavy manual labourers fare worse; trauma and early-stage Kienböck's fare better
- 13 studies, 293 patients with neutral or positive ulnar variance (radial shortening biomechanically inappropriate)
- Isolated capitate shortening osteotomy (125 patients) gave reliable relief: persistent pain 10.4%, revision 5.6%
- Combined decompression plus revascularization appeared most useful in Stage IIIA disease
- Evidence is predominantly Level IV case series with marked heterogeneity
Exam Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Scenario 1: Early Kienböck's Disease
"A 32-year-old male manual laborer presents with 6 months of wrist pain. X-rays show lunate sclerosis with no collapse. MRI confirms AVN with intact lunate architecture. Ulnar variance is negative 3mm."
Scenario 2: Advanced Kienböck's with Scaphoid Rotation
"A 45-year-old presents with chronic wrist pain and stiffness. X-rays show lunate collapse with scapholunate angle of 70 degrees. CT shows intact capitate head cartilage. What is your assessment and management?"
Scenario 3: Stage I Kienböck's - Management Debate
"A 28-year-old woman has wrist pain for 3 months. X-rays are normal but MRI shows low T1 signal in the lunate with bone marrow edema. Ulnar variance is neutral. How do you manage this Stage I disease, and what does the evidence say about early intervention?"
MCQ Practice Points
Most Important Prognostic Factor
Q: What Lichtman stage represents the critical prognostic divider in Kienböck's disease? A: Stage IIIB - scaphoid rotation (scapholunate angle over 60°) indicates fixed carpal collapse and instability. Joint-preserving surgery (leveling, revascularization) is ineffective beyond this point; salvage procedures required.
Ulnar Variance Significance
Q: What percentage of Kienböck's disease patients have negative ulnar variance? A: 78% - compared to 23% in the general population. Negative variance increases lunate loading by shifting axial load away from the ulnocarpal joint.
Gold Standard Investigation
Q: What is the investigation of choice for detecting Stage I Kienböck's disease? A: MRI - detects bone marrow edema and low T1 signal before radiographic changes appear. X-rays are normal in Stage I.
Radial Shortening Biomechanics
Q: By what percentage does radial shortening osteotomy decrease lunate loading? A: 45% - shortening the radius 2-4mm redistributes axial load from radiocarpal (lunate) to ulnocarpal articulation, unloading the lunate.
PRC Requirements
Q: What are the key requirements for successful proximal row carpectomy in Kienböck's disease? A: Intact capitate head cartilage AND intact lunate fossa (radiocarpal) cartilage. Any arthritis at these articulation sites is a contraindication; fusion would be preferred.
Most Common Salvage Procedure
Q: What is the most common motion-preserving salvage procedure for Stage IIIB Kienböck's disease? A: Proximal row carpectomy (PRC) - provides 80% pain relief and preserves 50% wrist motion. Durable for 10+ years if cartilage is intact.
Guidelines, Registries & Global Practice
Global epidemiology. Kienböck's disease is rare worldwide; most hand surgeons see only a handful of cases per year. It clusters in men aged 20-40, frequently in manual or vibration-exposed occupations (construction, drilling, mining). Negative ulnar variance is over-represented compared with the general population, though it is a predisposing rather than causal factor. There is no high-quality population incidence figure, and there is no implant registry for Kienböck's surgery because most procedures are osteotomies, fusions or carpectomies rather than arthroplasty.
No single global guideline — practice is built on cohort evidence and consensus. No society publishes a formal Kienböck's treatment guideline equivalent to a fracture protocol. Practice converges on staging-driven algorithms.
How Practice Differs by Setting and School of Thought
| Source / setting | Staging emphasis | Early disease (Stage I-II) | Advanced (IIIB-IV) |
|---|---|---|---|
| North American (AAOS-aligned, ASSH teaching) | Lichtman radiographic + arthroscopic cartilage grading | Unloading osteotomy or vascularized graft; MFC free flap in selected young patients | PRC favoured if capitate/lunate fossa intact |
| UK / European (BSSH, FESSH, AO teaching) | Lichtman plus Schmitt MRI perfusion grade | Radial shortening for negative variance; conservative trial common in Stage I | PRC or four-corner fusion per surgeon preference |
| Asian high-volume centres | Strong interest in capitate shortening and combined revascularization | Capitate shortening when variance is non-negative; vascularized pedicled graft | Limited carpal fusion; arthroplasty in low-demand only |
| Limited-resource settings | Plain radiographs only (MRI often unavailable) | Immobilization, activity modification; osteotomy where fixation available | Wrist fusion as reliable, low-cost salvage |
Registry and high- vs limited-resource practice. Where MRI is freely available, Stage I disease is detected early and unloading or revascularization is offered before collapse. Where MRI is scarce, diagnosis is later and total wrist fusion becomes the dependable salvage because it needs no specialist implant and reliably abolishes pain. Vascularized bone grafting and medial femoral condyle free flaps are concentrated in microsurgical referral units. Documenting the neutral-rotation ulnar variance on every wrist radiograph remains a universal, resource-independent standard because it determines whether radial shortening or capitate shortening is the appropriate unloading procedure.
Consent essentials (universal). For salvage surgery, counsel explicitly on the motion-versus-pain-relief trade-off (PRC preserves roughly half of wrist motion; total fusion removes motion but most reliably relieves pain), and on progression risk if early-stage disease is managed non-operatively.
KIENBĂ–CK'S DISEASE
Clinical summary
Key Anatomy
- •Lunate = keystone of proximal carpal row
- •Vascular supply: Y-pattern (80%) or single vessel (20%)
- •Type II anatomy (single vessel) = higher AVN risk
- •Ulnar variance: negative in 78% vs 23% normal population
Lichtman Staging (Modified)
- •Stage I: Normal X-ray, MRI shows AVN
- •Stage II: Sclerosis, no collapse
- •Stage IIIA: Collapse, scaphoid angle less than 60°
- •Stage IIIB: Collapse + scaphoid rotation over 60° (CRITICAL)
- •Stage IV: Generalized carpal arthritis
Investigations
- •MRI: Gold standard, detects Stage I before X-ray
- •X-ray: Measure ulnar variance on neutral PA view
- •CT: Surgical planning, assess capitate head for PRC
- •Scapholunate angle: over 60° = Stage IIIB (DISI)
Treatment Algorithm
- •Stage I: Immobilization 3-6 months, serial MRI
- •Stage II: Radial shortening if negative UV (60-80% success)
- •Stage IIIA: Joint leveling or consider PRC
- •Stage IIIB: PRC (if intact cartilage) or four-corner fusion
- •Stage IV: Total wrist fusion (gold standard for pain)
Surgical Pearls
- •Radial shortening: Decrease lunate loading 45%
- •4+5 ECA graft: Vascularized from distal radius
- •PRC: Requires intact capitate and radiocarpal cartilage
- •PRC outcomes: 80% pain relief, 50% motion, durable 10+ years