Co-authors: Milford H. Marchant Jr., M.D., Allston Stubbs, M.D., Carl J. Basamania, M.D.
March 15, 2005
- Background:
- Definition: In situ death of bone within the humeral head due to disruption of blood supply
- Other Names: Avascular Necrosis or Aseptic Necrosis
- Initially described in the Humeral Head in 1960 by Heimann and Freiberger (NEJM)
- 2nd Most common site of Osteonecrosis (Femoral Head = 1st)
- Knowledge based largely on extrapolated data from the Femoral Head
- Similar Etiology - Different Disease
- Non-Weight Bearing Joint
- Greater Vascular Watershed
- Functional capacity of shoulder is more forgiving
- Glenohumeral Joint is Less Constrained
- Progressive Osteoarthritis of Glenohumeral Joint (5%)
- Etiology / Associated Diseases:
- Primary
- Posttraumatic (Fracture / Dislocation)
- Corticosteroid therapy
- Hemoglobinopathies - Sickle Cell Disease
- Alcohol Abuse / Smoking
- Dysbarism (Decompression Sickness)
- Gaucher Disease
- Other
- Septic Osteonecrosis - Connective Tissue Disorders
- Hypercoagulable Disease - Chemotherapy
- Peripheral Vascular Disease - Chronic Dialysis
- Hyperlipidemia - SLE
- Cushing's Syndrome - Pregnancy
- Hyperuricemia - Myxedema
- Radiation Therapy - Pancreatitis
- Anatomy / Blood Supply:
- Humeral Head is directly supplied by the Anterior & Posterior Humeral Circumflex arteries
- Several Anastomotic contributions
- Suprascapular a.
- Thoracoacromial a.
- Subscapular a.
- Primary = Anterolateral branch of the Anterior Humeral Circumflex Artery
- Course:
- Branch off Axillary Artery
- Joins Surgical Neck of Humerus at the inferior border of Subscapularis Tendon
- Anterolateral Branch travels proximal and lateral to Intertubercular groove
- Enters Head at transition from Intertubercular groove to Greater Tuberosity
- Arcuate Artery of Laing = artery within the humeral head
- Microvasculature
- Subchondral bone is especially vulnerable
- Arterioles become sinusoids which make 180 degree turns to return to the
intraosseous circulation
- Vulnerable to thrombotic/embolic events
- Pathogenesis:
- Humeral Head Blood Supply Compromised
- Etiology of Compromise (Mankin, et al. (1992))
1. Mechanical Disruption of Blood Vessels
2. Arterial Obstruction = Thrombosis / Embolism
3. Injury or Compression of Arterial Walls
4. Venous Outflow Obstruction (Chandler's Disease)
- Nontraumatic necrosis of bone (osteonecrosis).
- Site of Compromise (Hungerford (1981))
1. Intraosseous - Extravascular (Intraosseous Pressure)
2. Intraosseous - Arterial
3. Extraosseous - Arterial
4. Venous
- Pathogenetic considerations in ischemic necrosis of bone.
- Trauma
- Fracture / Dislocation / Shoulder Surgery can physically disrupt blood supply
- Greatest risk: 4-part fractures
- Fractures involving the Anatomic Neck
- Incidence variable = 15% - 30% of 4-part fractures (Lee and Hansen (1981))
- Low compared to similar injuries in the hip
- Creeping Substitution: New bone is deposited on dead trabecular scaffold
- Rich Vascular supply in Soft Tissues surrounding the joint
- Post-traumatic avascular necrosis of the humeral head in displaced proximal humeral fractures.
- Corticosteroids
- Most Common reported cause of non-traumatic Osteonecrosis
- Occurs most commonly with high-dose administration or long-term use
- Several Case reports of varying duration of use, dose, and route of administration
- Impossible to predict:
- Occurrence
- Timing (6 - 18 months)
- Joint involvement
- Confounding variable in certain diseases
- Mechanism is still obscure
- Vasculitis
- Stress Fractures
- Hypercoagulopthy
- Alterations in fat metabolism: Enhanced Lipid Production
- Theories
- Intraosseous - Extravascular
- Increased Intraosseous Adipocyte Size
- Leads to increased intraosseous pressure and ischemia
- Intraosseous - Arterial
- Fatty changes in liver & Increased serum lipids
- Fat Embolism and Coagulation Abnormalities
- Cadaveric & Biopsy Studies demonstrated fat emboli in subchondral vessels
- Animal Model (Motomura, et al. (2004)
- Rabbits given High Dose Methylprednisolone
- Treatment with Warfarin and Probucol
- Pathology: Statistically significant reduction in size of Adipose Cells in Bone Marrow
- Results: Statistically significant ecrease incidence of Osteonecrosis
- Combined effects of an anticoagulant and a lipid-lowering agent on the prevention of steroid-induced osteonecrosis in rabbits.
- Hemoglobinopathy
- The most common cause of Osteonecrosis World-Wide (Milner, et al. (1993))
- Sickle Cell Disease is most prevalent
- Sickle Cell Disease & alpha-thalesemia have highest incidence of Osteonecrosis
- Higher baseline HCT
- Proposed Mechanisms
1. Emboli cause microinfarcts in subchondral bone
2. Chronic Hemolytic Anemia causes Bone Marrow Hyperplasia
- Results in increased marrow pressure and ischemia
- Sickle Cell Disease (Milner et al. (1993) & David, et al. (1993))
- 2524 pts with Sickle Cell Disease
- Prevalence of Humeral Head Osteonecrosis = 5% - 28%
- 2.9 cases per 100 patient years
- 67% developed Bilateral Disease
- Osteonecrosis of the humeral head in sickle cell disease.
- The shoulder in sickle-cell disease.
- Dysbarism
- Nitrogen gas bubbles
- Air embolism - Arterial congestion and Ischemia
- Damage to adipose tissue & Release of Vasoactive substances
- Promotion of Thrombosis
- Gaucher Disease
- Lipid Lysosomal Storage Disease - Autosomal Recessive
- Defect in Beta-glucosidase
- Accumulation of Glycolipid "Glucosylceramide" in liver, spleen, and bone marrow
- Excess Glycolipid within Marrow Cells (Gaucher Cells)
- Leads to increase in intraosseous pressure and vascular occlusion
- Damaged macrophages release substances which cause vasospasm
- Alcohol Abuse / Smoking
- Proposed Mechanism is similar to corticosteroids
- Alcohol use leads to fatty changes in liver
- Compounded - Alcohol increases systemic cortisol
- Smoking causes vasoconstriction which further increases risk for developing osteonecrosis
Biomechanics:
- Lesion Location: Superior Central Portion of Humeral Head is most common
- Corresponds to Glenohumeral contact region:
- 60 degrees of Humeral Elevation
- 90 degrees of Forward Flexion / Abduction
- Zone of Injury - Disease Progression
- Ischemic Bone Injury
- Vascular ingrowth at the periphery of the lesion
- Focal Osteopenia
- Migration of Mesenchymal stem cells into necrotic cancellous bone
- Macrophages resorb dead tissue and osteoblasts lay down new bone
- Interspersed Thickened Trabeculae surround lesion
- Resorption occurs faster than Restoration
- Weakened Subchondral bone
- Microfractures (18 - 24 months)
- Collapse of articular surface under normal stresses of joint motion = Flattening
- Articular Cartilage Degeneration
Classification / Radiology:
- Cruess Classification System (Cruess (1978))
- Modified from Ficat & Arlet Classification of Femoral Head osteonecrosis
- No clinical or functional parameters - based solely on bony change on Plain Radiographs
Stage I
- Changes not yet visible on Plain Radiographs
- Can be detected on MRI
- Clinical Signs and Symptoms are diffuse
Stage II
- Sclerosis: Wedge Shaped, Mottled,Diffuse
- Area of Osteopenia
- Sphericity Maintained
Stage III
- "Crescent Sign" = Subchondral Fracture
- Minimal Depression of Articular Surface
Stage IV
- "Flattening" = Collapse of Joint Surface and Subchondral bone
- Fragmentation
- Loose Bodies
- Secondary Arthritis
Stage V
- Degenerative Disease Extends to Involve Glenoid
- The current status of avascular necrosis of the femoral head.
- MRI
- Useful for identifying and quantifying pre-collapse disease (Radiographic Stage I & II)
- Provides No Advantage once diagnosis has been made
- Exception - May identify disease in symptomatic contralateral shoulder with normal x-rays
Clinical Evaluation / Natural History:
- Presentation
- Patients are younger than most arthritis patients
- Insidious onset of Shoulder Pain - Prevents normal ADL
- Night Pain / Difficulty Sleeping
- Painful Click / Crepitus
- Physical Examination
- Active / Passive ROM often preserved until late stage disease
- Discomfort greatest at 90 degrees of elevation / abduction
- Evaluation
- H&P
- Risk Factor Assessment
- Labs to rule out infection +/- serology testing
- Shoulder X-rays
- Evaluate for Additional Site Disease
- Additional Site Disease (L'Insalata, et al. (1995))
- Reviewed 42 patients / 65 shoulders with Humeral Head Osteonecrosis
- Women > Men / Avg. Age at Diagnosis = 46y
- 55% had Bilateral Humeral Disease
- 76% had osteonecrosis at other sites
- 69% Hip
- 29% Femoral Condyle
- 9% Talus
- Humeral head osteonecrosis: clinical course and radiographic predictors of outcome.
- Natural History
- Variable - appears to be slow
- Many patients present with late stage disease
- Non-weight bearing joint with soft tissue constraints
- Etiology dictates progression
- Sickle Cell Patients have most benign course symptomatically
- Low requirement for surgery even with advanced disease
- Corticosteroid users have variable course
- Dependent on stage of presentation
- Post-Traumatic patients often require surgical intervention
Treatment
- Goals
- Preserve Shoulder Function
- Strength
- ROM
- ADL's
- Halt progression of disease
- Decrease symptoms
- Decision for Surgical Intervention based on Radiographic Stage & Clinical Symptoms
- Conservative Treatment = Stage I & II Disease
- Patient Education
- Reduction of Risk Factors
- Stop Alcohol / Tobacco use
- Judicious use of corticosteroids
- Physical therapy
- Preserve Shoulder Motion
- Activity Modification
- Avoiding Overhead Activities
- NSAIDs may provide some symptom relief
- Surgical Treatment
- Indications:
- Failure of Non-op tx: Core Decompression vs. Arthroplasty
- Traumatic Osteonecrosis(Basamania, et al. Abstract 64th AAOS Meeting. 1997)
- Treatment of post-traumatic versus non-traumatic osteonecrosis of the shoulder
- Non-operative treatment of post-traumatic osteonecrosis was unsuccessful
- 41% of non-traumatic pts were treated successfully with Therapy & activity modification
- Core Decompression
- Goal: Reduce intraosseous - extravascular pressure to reestablish blood flow
- Adapted from use in the Femoral Head
- Best used in treatment for non-traumatic early stage disease (Stage I, II, III)
- Varying success rates (40% - 90%)
- Success may be similar to Natural History of disease
- Original Technique (Mont, et al.):
- 2cm to 3cm Incision Axillary Fold
- Deltopectoral Approach to humeral metaphysis
- Guide Wire advanced to within 1cm of subchondral surface
- Position checked under Fluoroscopy
- 5mm coring device lateral to bicipital sulcus
- 1 to 3 biopsies performed depending on lesion size
- Post-op Sling 3 - 5 days - activity advanced gradually
- Results
- Mont, et al. (1993) Retrospective Review
- 30 decompressions - 20 pts atraumatic osteonecrosis
- Patients failed conservative tx after avg. 9.6 months
- Varying stages of disease
- Over-all 73% Good-Excellent Results Post-op UCLA Shoulder Scores
- Stages I & II : 14/14 shoulders G-E
- Stage III : 7/10 shoulders G-E
- Stage IV : 1/6 shoulders G-E
- Avascular necrosis of the humeral head treated by core decompression. A retrospective review.
- L'Insalata et al. (1996)
- 5 Stage III patients
- Pre-op: 0 - 1 mm of articular incongruity
- All had clinical progression of disease
- 4/5 required arthroplasty within 3 years
- Humeral head osteonecrosis: clinical course and radiographic predictors of outcome.
- LaPorte, et al (1998)
- Assessed Long-term outcome of Core Decompression
- 43 patients / 63 shoulders with mean f/u 10 years
- Avg. Age: 36 (22 - 76)
- Atraumatic Osteonecrosis
Stage I : 94% (15/16) successful
Stage II : 88% (15/17) successful
Stage III : 70% (16/23) successful
Stage IV : 14% (1/7) successful
- Average Time to Failure = 24 months
- Osteonecrosis of the humeral head treated by core decompression.
- Arthroplasty
- Prosthetic replacement of damaged articular surface
- Useful when treating later stage disease (III, IV, V) - especially post-collapse disease
- Osteonecrosis represents approximately 5% of patients requiring arthroplasty
- Reliable means of restoring range of motion and providing pain relief
- 90% to 100% Pain relief reported in literature for osteonecrosis
- Good results for ROM in non-traumatic diseasae
- Hemi-arthroplasty vs. Total Shoulder Arthroplasty remains controversial
- Most Agree to Press Fit Humeral Component
- Glenoid resurfacing in Stage V disease with intact or reparable Rotator Cuff