Legg Calve Perthes Disease

Other Names

• Coxa plana
• Legg-Perthes
• Legg Calve
• Perthes disease
• Idiopathic osteonecrosis of the capital femoral epiphysis of the femoral head
• Idiopathic avascular necrosis of the capital femoral epiphysis of the femoral head
• Osteochondrosis of the femoral head

Pathophysiology

• General
• Interruption of vascular supply theory
  • Unclear whether it is an arterial infarction? or venous congestion
  • Systemic? coagulopathy? may play a role
• Trauma?
  • Acute? Trauma to the immature hip may ben an accessory etiologic factor
  • Repetitive mechanical stress may also be implicated
• Proposed four-phase model
  • 1) Necrosis
    • Disruption of the blood supply causing infarction, bone softening and death of the femoral capital epiphysis
  • 2) Fragmentation
    • Resorption of infarcted bone.
  • 3) Reossification
    • Osteoblastic activity and reforms the femoral epiphysis
  • 4) Remodeling
    • New femoral head reshapes during growth and response to conservative treatment? will usually show healing in 2-4 years 

• Coagulation disturbance
  • Increased coagulability including inherited? coagulopathies (ie, Factor V Leiden), thrombophilias, and hypofibrinolysis
  • 2012 meta-analysis: found factor V leiden, Prothrombin II increased risk, but not MTHFR polymorphism
• Inflammatory markers
  • Increased interleukin-6 (IL-6) polymorphism (G-174C/G-597A)
• Genetics
  • Collagen type II gene COL2A1 mutation
  • Proapoptotic factor Bcl-2-associated X protein (Bax)
  • Twin-twin studies have identified a genetic? relationship
• HIV (Up to 5% of HIV patients have avascular necrosis of the hip)
• Secondhand smoke exposure
  • Maternal smoking
• Low socioeconomic status (SES)
  • Generally low SES
  • In rural areas
• Microsomia
  • Birth weight? < 2.5 kg in boys
• Anthropometrics
  • Short stature
  • Obesity
• Caucasian and Asian ethnicity 
• Psychiatric
  • Attention Deficit Hyperactivity Disorder (ADHD)
• Mechanical stress
• Developmental
  • Delay in endochondral ossification in the proximal capital femoral epiphysis
• Other
  • Increased Vascular endothelial growth factor (VEGF) and hypoxia?-inducible factor (HIF-1) in rat models
  • Altered Insulin? growth factor 1 (IGF-1) expression in rat models

Differential Diagnosis?

• Fractures And Dislocations
  • Pelvic Fracture?
  • Hip Fracture
  • Acetabular Fracture
  • Femoral Neck Stress Fracture
  • Pelvic Stress Fracture
  • Hip Dislocation?

• Arthropathies
  • Osteitis Pubis
  • Avascular Necrosis of the Hip
  • Hip Osteoarthritis?
  • Femoroacetabular Impingement
  • Transient Osteoporosis? of the Hip

• Muscle and Tendon? Injuries
  • Hip Flexor Tendonitis?
  • Piriformis Syndrome
  • Hamstring Strain?
  • Proximal Hamstring Tendinopathy?
  • Adductor Strain
  • Greater Trochanteric Pain Syndrome

• Bursopathies
  • Iliopsoas Bursitis
  • Ischial Bursitis

• Ligament Injuries
  • Acetabular Labrum Tear

• Neuropathies
  • Meralgia Paresthetica

• Other
  • Snapping Hip Syndrome
  • Septic Arthritis
  • Gout
  • Leg Length Discrepancy
• Pediatric Pathology
  • Transient Synovitis of the Hip
  • Developmental Dysplasia of the Hip (DDH)
  • Legg-Calve-Perthes Disease
  • Slipped Capital Femoral Epiphysis (SCFE)
  • Avulsion Fractures of the Ilium (Iliac Crest, ASIS, AIIS)
  • Ischial Tuberostiy Avulsion Fracture
  • Avulsion Fractures of the Trochanters (Greater, Lesser)
  • Apophysitis of the Ilium (Iliac Crest, ASIS, AIIS)

Diagnosis

• History
  • Limp of acute or insidious onset from between 1 to 3 months
  • If present, pain localized to the hip with or without referred pain to the knee, thigh, or abdomen
    • May worsen with activity
  • No systemic symptoms (ie, fever, chills, weight loss, migratory joint pains) should be found
• Physical Exam Physical Exam Hip
  • Decreased internal rotation and abduction of the hip
  • Pain on rotation referred to the anteromedial thigh and/or knee
  • Atrophy of thigh & buttock muscles
• Special Tests
  • Trendelenburg Gait or antalgic gait may be present depending on the chronicity ^[24]

Radiographs

• Standard Radiographs Hip
  • AP Pelvis, Frog leg views
• Early Findings
  • Widening of joint space (epiphyseal cartilage hypertrophy)
  • Changes in the epiphysis (smaller, appears denser)
• Late Findings
  • Flattening of the femoral head, fragmentation, healing (sclerosis)

MRI

• Bone Scan and MRI may be used if X-ray are unequivocal
  • Bone scans show decreased perfusion to the femoral head
  • MRI may show marrow changes ^[26]

Classification

Lateral Pillar or Herring Classification

• Clinical utility: Prognostication
  • Wiig et al found: 70% of lateral pillar A hips, 51% of lateral pillar B hips, and 30% of C hips had Stulberg I or II outcomes^[27]
• Group A: lateral pillar is at full height with no density changes
  • Consistently good prognosis.
• Group B: lateral pillar maintains greater than 50% height
  • Poor outcome if the bone age is greater than 6.
• Group C: Less than 50% of the lateral pillar height is maintained
  • All patients will experience a poor outcome. ^[28]

Stulberg classification

• The gold standard for rating residual femoral head deformity and joint congruence on the radiograph
  • Recent studies show poor interobserver and intraobserver reliability
• I: Normal, congruent Hip
  • Arthritis does not develop
• II: Spherical head, concentric in acetabulum on AP, frog-leg lateral
  • Shortened femoral neck, abnormally steep acetabulum
• III: Ovoid, mushroom or umbrella-shaped femoral head; not flat
  • Mild-to-moderate arthritis in adulthood
• IV: Flathead and acetabulum, congruent joint
• V: Flat femoral head, normal femoral neck, and acetabulum with incongruent joint
  • Severe arthritis before 50 years of age

Treatment

• Goal: maintain the sphericity of the femoral head and the congruency of the femur-acetabulum relationship
  • Prevent the development of secondary Hip Osteoarthritis

Prognosis

• Wiig et al found younger patients have better outcomes^[27]
  • 57% of patients <6 years were found to be Stulberg I or II
  • Only 38% of patients >6 years were found to be Stulberg I or II
• Lateral Pillar Classification (degree of femoral head involvement: A [least] to C [most])
  • >8 years old and patients in lateral pillar group B or B/C have better outcomes with surgery
  • <8 years old and patients in group B do well regardless of treatment choice
  • Patients in lateral pillar C group do poorly regardless of age or treatment method
  • Group C patients experience poor outcomes regardless of treatment choice
• Recovery
  • 50% of patients almost fully recover with no long-term sequelae (need citation)
• Pain and Disability
  • 50% of patients develop pain, disability, degenerative joint disease and in their 40-50s leading to hip replacement in 60s-70s.
• Gender
  • Female patients have worse outcomes if onset occurs >8 years of age ^[26]

Nonoperative

• Indications
  • Children with bone age less than 6 or lateral pillar A involvement
• Activity restriction and protective weight-bearing until ossification is complete
• NSAIDs can be prescribed for comfort
• Treatment Options: Bracing, No treatment, Range of Motion
  • Herring et al found no difference between these three treatment choices ^[29]

Operative

• Femoral or Pelvic Osteotomy
  • Indications: children older than 8 years
  • Lateral pillars B and B/C have improved outcomes with surgery compared to A and C
  • Studies suggest early surgery before femoral head deformity develops
• Valgus or Shelf Osteotomies
  • Indications: children with hinge abduction
  • Improves abductor mechanism
• Hip Arthroscopy
  • It May be used for treating mechanical symptoms and impingement