A7: Complications Flashcards
What is a non-union / pseudarthrosis?
Fracture that fails to unite in the expected time and show no further progression
What is a delayed union?
Takes longer than normal to heal, but still shows progression
What are the two outcomes of delayed union?
Union or non-union
What are some factors that affect rate of fracture union?
Stability, vascularity, bone grafting, soft tissue trauma, defects, cortical or cancellous bone
What are the three types of viable non-unions?
Hypertrophic (elephant foot callus), slightly hypertrophic, oligotrophic
What are the four types of non-viable non-unions?
Dystrophic, necrotic, defect, atrophic
What is a more simple way to classify non-unions?
Hypertrophic (viable) or atrophic (non-viable)
Which factors result in an atrophic non-union?
Absence of callus, large gap, round ends, closed medullary cavity, disuse osteoporosis
What are some causes of non-union?
Inadequate stabilisation, excessive fixation, loss of blood supply, large gap, necrosis from severe comminution, osteomyelitis
Where is a risk factor for non-union in toy breed dogs?
Distal radius
Where is a risk factor for non-union in cats?
Tibia with ESF
What is “the unhappy triad” of osteomyelitis?
Infection, bone resorption, implant loosening and fracture instability
Are flexible or rigid plates better for fracture healing?
Flexible
What are some possible reasons excessive rigidity inhibits fracture healing?
Stress protection? Bone atrophy? Lack of micromotion? Damaged blood supply?
What is Key’s hypothesis?
That there is a critical size defect - over 1.25x bone diameter, you get atrophic non-union
Where is a high risk for non-union in cats and small breed dogs?
Distal radius
What happens at the distal radius in non-union in cats?
Slightly hypertrophic
What happens at the distal radius in non-union in small breed dogs?
Atrophic
Where else is possibly a high-risk site for non-union in cats?
Tibia
How can you diagnose non-union?
Pain, atrophy, joint stiffness, palpable instability, limb deformity, radiographic signs
What are some possible ways to treat a non-union?
Surgery, resect fibrous tissue and bone ends, take a culture, remove the callus, open medullary cavities, stabilise, bone graft, remove loose implants
What are some problems with surgically exposure of a non-union?
Anatomic approach, haemorrhage, scar tissue, neurovascular bundles
What do you resect in an atrophic non-union?
Scar tissue
What is one way to stabilise a non-union?
Use a DCP on the tension side with a tensioning device and 3-5 screws in each fragment
What is “wave plate” stabilisation?
Put a graft over the callus, and a plate over that
What is a disadvantage of “wave plate” stabilisation?
Increased fatigue life of plate
What do you use to open the medullary cavity?
1.5mm drill
What can you do in hypertrophy?
Remove the callus
Where can you collect a cancellous bone graft?
Proximal humerus, pelvis
What can you use to open the cortex?
Drill, pin, trephine
Which kind of graft is the most osteogenic?
Autogenous cancellous
What are the three Os of graft action?
Osteogenesis, osteoinduction, osteoconduction
What can aftercare of repeat surgery include?
Restrict activity, physiotherapy for contracture and stiff joints, radiographic monitoring, monitor stability, repeat bone graft
What is a Jonas pin?
A spring-loaded IM pin
