Fixation evaluation, fracture disease, and fracture healing Flashcards Preview

Small animal surgery I > Fixation evaluation, fracture disease, and fracture healing > Flashcards

Flashcards in Fixation evaluation, fracture disease, and fracture healing Deck (25)
1

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

Apposition

Alignment

Apparatus

Activity

2

What are you looking for when assessing apposition on post-op or re-check radiographs?

  • Are the fracture edges touching?
  • Only very important in articular fractures
    • Not important in biological osteosynthesis 

3

What are you looking for when assessing the activity level in post-op or re-check rads?

  • Is there evidence of:
    • Bone healing--callus spanning across fracture
    • Infection--more lucency, too much periosteal activity
    • Osteopenia
    • Malunion

4

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

Radiolucency around screw heads 

ALWAYS compare to original radiographs!

5

What radiographic changes are consistent with osteomyelitis?

Proliferative/lytic appearance

6

What are the 2 types of non-union?

  • Viable = biologically active fracture with cartilage and fibrous tissue between fracture ends
  • Non-viable = fracture ends are sclerotic with rounded bone edges and visible fracture gap

7

What is the recommended treatment for non-union fractures?

Appropriate stabilization and cancellous bone autographs

Partial mandibulectomy is an option for treatment of chronic non-union of the mandible

8

What is the pathogenesis of quadriceps contracture?

  • Muscle fibers are replaced by fibrous tissue
  • Adhesions form between muscle and bone
  • Changes result in severe decrease in limb motility
  • Periarticular fibrosis/joint ankylosis/DJD further inhibits limb function
  • Often irreversible

9

What are the risk factors associated with quadriceps contracture?

  • Distal femoral fractures
  • Young patients (< 6mo)
  • Prolonged immobilization
  • Extensive muscle/ST trauma

10

What treatment options are available for quadriceps contracture?

Rehabilitation (ROM exercises + NSAIDs) to prevent muscle atrophy and scar tissue

Treatment is rarely successful

11

T/F: The prognosis for quadriceps contracture (with treatment) is poor for full function and guarded for partial function

TRUE

12

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

Disuse osteoporosis

Muscle atrophy

Ligamentous laxity

Also: cartilage atrophy, digital flexor contracture, and fracture-associated sarcoma

13

What is the difference between disuse osteoporosis and muscle atrophy?

  • Disuse osteoporosis
    • Decrease in stress application to the bone --> increased osteoclast activity
    • Can occur with casts and excessively strong implants/fixators
  • Muscle atrophy
    • Secondary to disuse or immobilization
    • Reversible
      • Can take significant time to return to normal

14

What is ligamentous laxity?

  • Associated with muscle atrophy from disuse or immobilization
  • Loose ligaments result in joint instability
  • Should resolve with improved muscle tone

15

What radiographic changes are expected for an aggressive, neoplastic bone lesion?

  • Cortical lysis
  • Periosteal reaction
  • +/- mineralization of surrounding soft tissues
  • Loss of trabecular pattern
  • Lack of distinct border between normal and abnormal bone

16

What are some differential diagnoses to keep in mind when observing radiographic changes due to an aggressive, neoplastic bone lesion?

  • Osteomyelitis
  • Osteosarcoma
  • Bacterial, fungal infections
  • CSA, FSA, HSA
  • Lymphoma
  • Bone cyst

17

Which osteosarcoma treatment option is associated with the longest MST?

Limb-sparing surgery--local removal of tumor with wide margins and the bone is replaced with graft, prosthesis or regenerated via bone transport osteogensis

18

What is the purpose of amputation of a limb affected with osteosarcoma if there is no change in MST?

Removes the source of pain, especially in cases of pathological fracture

19

What are the most common sites for metastasis of osteosarcomas?

Lungs, local LN, other bones

(Usually located towards the elbow and away from the knee)

20

What staging is recommended with osteosarcomas?

  • 3 view thoracic rads or thoracic CT
    • CT >>> rads when diagnosing pulmonary metastasis
  • Aspiration of any enlarged LN
  • CBC/chemistry/UA
    • Increased ALKP is assoc. w/ poorer prognosis

21

T/F: Micrometastases are present in most patients at time of initial diagnosis

TRUE

22

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

Biopsy

23

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

Distal radial lesions have the best outcome

24

Other than osteosarcomas, what primary bone tumors are diagnosed in small animal patients?

Chondrosarcoma, fibrosarcoma, hemangiosarcoma

25

What tumor types are specific to the digits?

  • Dogs
    • Squamous cell carcinoma and melanoma
  • Cats
    • Squamous cell carcinoma, fibrosarcoma, adenocarcinoma, osteosarcoma, hemangiosarcoma