KIENBÖCK'S DISEASE
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
Examiner's 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
Memory Hook:I See Carpal Arthritis = the natural progression of untreated Kienböck's disease from invisible to end-stage!
LUNATERisk Factors for Kienböck's Disease
Memory Hook:LUNATE = the bone that dies! Remember the risk factors that predispose to AVN.
PRC-FSalvage Surgery Options
Memory 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
Consider: Scapholunate ligament injury, triangular fibrocartilage complex (TFCC) tear, ulnocarpal impaction, carpal boss, occult fracture. MRI differentiates AVN from ligamentous pathology.
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
- Review of radial shortening for Kienböck's disease
- 60-80% good outcomes in Stage II-IIIA
- Best results with negative ulnar variance
- Decreases lunate loading by 45%
- PRC for Stage IIIB-IV Kienböck's disease
- 80% pain relief, 50% motion preservation
- Good 10-year durability
- Capitate-radius arthritis in 20% at 10 years
- MRI classification of Kienböck's disease
- Detects AVN before X-ray changes (Stage I)
- Bone marrow edema precedes sclerosis
- Guides early intervention
- Modified Lichtman classification (4 stages)
- Stage IIIB (scaphoid rotation) = critical divider
- Guides treatment algorithm
- Widely accepted staging system
- 4+5 ECA vascularized bone graft for Kienböck's
- Variable outcomes: 40-80% success
- Best results in Stage II with viable lunate on MRI
- Technically demanding procedure
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
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.
Australian Context
Epidemiology in Australia: Kienböck's disease is uncommon in Australia with most hand surgeons encountering fewer than 5 cases per year. The condition is more frequently seen in males aged 20-40 engaged in manual labor, particularly in industries involving vibration exposure such as construction and mining. Referral to specialist hand surgery units is recommended for surgical management given the rarity and complexity of treatment options.
Management Considerations: Australian hand surgeons typically follow the Lichtman staging system for treatment decisions. MRI is readily accessible and recommended by RACS for early diagnosis in suspected AVN. Joint leveling procedures (radial shortening) are performed for Stage II disease with negative ulnar variance, while PRC remains the preferred salvage option for Stage IIIB in appropriately selected patients. WorkCover claims may be relevant for patients in high-vibration occupations (jackhammer operators, power tool users), requiring documentation of occupational history.
Medicolegal Considerations: Informed consent for salvage procedures should address the trade-off between motion preservation and pain relief, particularly for PRC versus fusion decisions. Counseling about progression risk is essential if conservative management is chosen for early-stage disease. Documentation of ulnar variance measurement on all wrist radiographs is recommended. Consider seeking second opinion for young patients before proceeding to irreversible total wrist fusion.
KIENBÖCK'S DISEASE
High-Yield Exam 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