خبصة

• Bone tumors


  Classified into: Primary bone tumors (Benign, Malignant), Secondary bone tumors (Metastasis)

  
• Prognosis of bone cancer

  • Depends on: overall stage of disease, presence of metastasis, skip (discontinuous) lesions within the same bone, histologic grade, tumor size

  
• MSTS (Enneking) Staging System

  Most popular and useful for orthopaedic surgeons, defines malignant lesions using Roman numerals (I, II, III) and benign lesions using Arabic numbers (1, 2, 3)
• Tumor Grade


  Tumors are graded based on the percentage of cellular atypia, low grade tumors have low metastatic potential, high grade tumors have greater metastatic potential

  
• Primary Bone Tumors


  • Bone-forming tumors
  • Cartilage-forming tumors
  • Miscellaneous tumors
  • Hematopoietic tumors
  • Fibrous tumors

  
• Bone-Forming Tumors


  • Osteoid osteoma and osteoblastoma (Benign), Osteosarcoma (Malignant)

  
• Osteoid osteoma


  A small, discrete, painful, benign bone lesion
• Osteoid osteoma has a 3:1 male to female ratio and most commonly occurs in persons aged 5-25 years
• Osteoid osteoma


  • Most common locations: lower extremity (>50%), spine (10-15%), hand (5-10%), foot (<5%)
• Irritable hip


  A common childhood condition affecting up to 1 in 1000 children

  
• Possible aetiologies of irritable hip

  • Systemic infection, viral or bacterial
  • Trauma causing irritation of the hip capsule or bony contusion

  
• Osteoid osteoma symptoms


  Constant and progressive pain, worse at night and with drinking alcohol, relieved by NSAIDs, may mimic arthritis
• Transient synovitis


  Non-pyogenic inflammation and hypertrophy of the synovial membrane
• Osteoid osteoma imaging


  • Radiographs, CT, Bone scan, MRI
• Irritable hip


  • Usually occurs in children between 3 and 9 years of age
  • Twice as common in boys as in girls
  • Left and right hips affected roughly equally, but bilateral disease is rare
  • Up to 10% of children will have a recurrent episode

  
• Osteosarcoma


  The most common primary sarcoma of bone, usually occurs in children and young adults, most common site is the distal femur and proximal tibia

  
• Osteosarcoma


  • Most commonly diagnosed as Stage IIB (high grade, extra-compartmental, no metastases), 10-20% of patients present with pulmonary metastases
• Osteosarcoma imaging


  • Radiographs, MRI, Bone scan, CT

  
• Slipped capital femoral epiphysis (SCFE)


  Displacement of the capital femoral epiphysis from the femoral neck through the physeal plate, the most common hip condition among adolescents from age 10 to 15 with an incidence of 1 per 10000 worldwide

  
• Cartilage-Forming Tumors


  Osteochondroma (Benign), Chondroma (Benign), Chondrosarcoma (Malignant)
• Developmental dysplasia of hip (DDH)

  A disorder of abnormal development resulting in dysplasia and possible subluxation or dislocation of the hip secondary to capsular laxity and mechanical factors

  
• Pathophysiology of SCFE


  • Mechanical overloading leads to displacement through the proximal femoral physis
  • Slipping of the epiphysis typically occurs through the hypertrophic zone of the physis
  • Anatomically the hypertrophic zone often contains an anastomosis of the metaphyseal epiphyseal blood supplies
  • During adolescence, the periosteum begins to thin and the force required for displacement to occur is reduced
  • Internally, the physis is stabilized primarily by mammillary processes
  • Physeal widening up to 12 mm (normal width is 2–6 mm) in hips that undergo SCFE
• Osteochondroma


  • Mushroom shaped, range in size from 1 to 20 cm, outer layer is benign hyaline cartilage, inner portion is newly formed bone

  
• Biomechanical factors predisposing to SCFE

  • Changes in the shape of the proximal femur during growth leading to increased varus and a more vertically oriented physis
  • Larger body habitus and additional weight further increase shear forces
• Endocrine disorders associated with SCFE

  Hypothyroidism, osteodystrophy of chronic renal failure, and excessive growth hormone
• DDH encompasses a spectrum of disease

  • Dysplasia: a shallow or underdeveloped acetabulum
  • Subluxation: displacement of articular surface with some contact
  • Dislocation: displacement of articular surface with no contact
  • Teratologic hip: dislocated in utero and irreducible on neonatal exam
  • Late (adolescent) dysplasia: mechanically stable and reduced but dysplastic
• DDH


  • Most common orthopaedic disorder in newborns
  • Dysplasia incidence is 1:100
  • Dislocation incidence is 1:1000
• Risk factors for DDH

  • First born
  • Female (6:1 over males)
  • Family history
  • Oligohydramnios
  • Breech presentation
  • Twin pregnancy
• Pathophysiology of DDH


  1. Initial instability thought to be caused by fetal laxity, genetic laxity, and intrauterine and postnatal malpositioning

  2. Initial instability leads to dysplasia, dysplasia leads to gradual subluxation, then dislocation
• Chondrosarcomas comprise a variety of tumors sharing the ability to produce neoplastic cartilage
• Physical exam findings (< 3 months)

  • Palpable hip subluxation/dislocation on exam
  • Barlow: dislocates a dislocatable hip by adduction and depression of the flexed femur
  • Ortolani: reduces a dislocated hip by elevation and abduction of the flexed femur
  • Galeazzi (Allis): apparent limb length discrepancy due to a unilateral dislocated hip with hip and knee flexed, femur appears shortened on dislocated side

  
• Legg-Calve-Perthes Disease


  Idiopathic avascular necrosis of the proximal femoral epiphysis in children

  
• Barlow and Ortolani rarely positive after 3 months of age because of soft-tissue contractures
• Osteochondroma


  Bony excrescences with a cartilaginous cap; may be solitary or multiple and hereditary
• Physical exam findings (> 3 months)

  • Limitations in hip abduction, most sensitive test once contractures have began to occur
  • Decreased symmetrically in bilateral dislocations
  • Leg length discrepancy predominate (Galeazzi)

  
• Physical exam findings (> 1 year - walking child)

  • Pelvic obliquity
  • Waddling gait and lumbar lordosis, in response to hip contractures resulting from bilateral dislocations
  • Toe walking: compensate for relative shortening of affected side

  
• Pathophysiology of Legg-Calve-Perthes Disease

  Osteonecrosis occurs secondary to disruption of blood supply to femoral head, followed by revascularization with subsequent resorption and later collapse

  
• Radiographic findings


  • Hilgenreiner's line: horizontal line through right and left triradiate cartilage, femoral head ossification should be inferior to this line
  • Perkin's line: line perpendicular to Hilgenreiner's through a point at lateral margin of acetabulum, femoral head ossification should be medial to this line
  • Shenton's line: arc along inferior border of femoral neck and superior margin of obturator foramen, arc line should be continuous
  • Delayed ossification of the femoral head is seen in cases of dislocation
  • Acetabular index (AI): angle formed by a line drawn from point on the lateral triradiate cartilage to point on lateral margin of acetabulum and Hilgenreiner's line, should be less than 25° in patients older than 6 months

  
• Ultrasound


  • Evaluates for acetabular dysplasia and/or the presence of a hip dislocation, useful before femoral head ossification (<4-6 months)
  • Alpha angle: angle created by lines along the bony acetabulum and the ilium, normal is greater than 60°
  • Beta angle: angle created by lines along the labrum and the ilium, normal is less than 55°

  
• Degenerative spine disease


  Condition where the spine degenerates over time