Fracture Hodgepodge

Question 1

What are the 4 A’s of radiographic evaluation when reviewing post-op or recheck radiographs of a fracture repair?

Answer 1

• Apposition
• Alignment - MOST IMPORTANT FOR JOINTS
• Apparatus
• Activity

Question 2

Other than obvious implant migration, what is a radiographic change that would be indicative of implant loosening?

Answer 2

Loose around screw head

Question 3

What radiographic changes are consistent with osteomyelitis?

Question 4

Know the 2 types of non-union. What is the recommended treatment for non-union fractures?

Answer 4

• Visible
  
  • Biologically active fracture with cartilage and fibrous tissue between fracture ends
• Non-visible
  
  • Fracture ends are sclerotic with rounded bone edges and visible fracture gap

Additonal treatment is required to promote bone healing

Question 5

What is the pathogenesis of quadriceps contracture?

Answer 5

 Muscle fibers are replaced by fibrous tissue

 Adhesions form between muscle and bone

 Changes result in severe decrease in limb mobility

 Periarticular fibrosis/joint ankylosis/DJD further inhibits limb function

 Often irreversible

Question 6

What are the risk factors for quadriceps conjecture?

Answer 6

 Distal femoral fractures

 Young patients (< 6 months)

 Prolonged immobilization

 Extensive muscle/ST trauma

Question 7

What treatment options are available for quadriceps conjecture?

What is the prognosis for this condition?

Answer 7

Prevention is IMPERATIVE

 Internal or External Fixation

 Rehabilitation to prevent muscle atrophy and scar tissue

 PROM

 NSAIDs
 Treatment is rarely successful

 Prognosis with treatment
 Poor for full function
 Guarded for partial function

Question 8

What other morbidity is associated with overly rigid fixation and limb immobilization for treatment of a fracture?

Answer 8

Disuse Osteoporosis

Decreased in stress application to the bone results in increased osteoclast activity

 Wolff’s law!

 Can occur with casts and with excessively strong implants/fixators

Muscle Atrophy

Secondary to disuse or immobilization

 Reversible

 Can take significant time to return to normal depending on patient

Question 9

What radiographic changes are expected for an aggressive, neoplastic, bone lesion? What differential diagnoses should be considered when these changes are observed?

Answer 9

Radiographic Changes:

Cortical lysis

 Periosteal reaction

 +/- Mineralization of

surrounding soft tissues

 Loss of trabecular pattern

 Lack of distinct border between normal and abnormal bone

DDx:

Osteomyelitis

 Fungal or bacterial  CSA, FSA, HAS
 Lymphoma
 Bone Cyst

Question 10

What osteosarcoma treatment option is associated with the longest median survival time?

Answer 10

Amputation + Chemotherapy

Question 11

What is the purpose of amputation of the affected limb if there is no effect

on survival time?

Answer 11

Amputation alone does not improve median survival time

 MST ~3-4 months

 Resection of primary tumor

(local control)

 Removes source of pain (esp. in cases of pathologic fracture)

Question 12

What are the most common sites for metastatic lesions of Osteosarcoma?

What staging should be recommended?

Answer 12

Common sites:

Proximal humerus

 Distal radius or ulna
 Distal femur
 Proximal tibia
 Away from the elbow, towards the knee

Micrometastases are present in most patients at time of initial diagnosis

 Lungs
 Other bones  LNs

 Staging should include
 3 view thoracic radiographs or thoracic CT

 CT is superior to radiographs for diagnosis of pulmonary metastasis

 Aspiration of any enlarged LNs  CBC/Chemistry/UA

 Increase in ALKP associated with poorer prognosis

Question 13

What is the gold standard for obtaining a diagnosis of a bone lesion?

Answer 13

 Biopsy

 Gold standard for diagnosing OSA (or other neoplasias)

 Provides confidence that surgical recommendation (amputation or limb spare) is appropriate.

Question 14

What bone tumor locations are amenable to treatment by limb sparing?

Answer 14

Distal radial lesions have best outcome

Question 15

Other than osteosarcoma, what primary bone tumors are diagnosed in our small animal population?

Answer 15

 Primary
 Osteosarcoma (OSA)
 Chondrosarcoma (CSA)
 Fibrosarcoma (FSA)
 Hemangiosarcoma (HAS)

Question 16

What tumor types are specific to the digits?

Answer 16

Dogs: SCC and Melanoma

 Cats: SCC, FSA, AdCa, OSA, HSA