Check-up after a compression plate: why is there no callus?
4-year-old Beagle with a transverse radial fracture repaired with anatomical reduction and a compression plate. At the 8-week check it bears weight well and without pain. Radiographs show the fracture line fading, no visible periosteal callus and secure implants.
How do you interpret this progress?
chevron_right Show answer and explanation
A. It is an atrophic non-union, since there should be callus by 8 weeks
In a non-union the fracture line persists or widens, with rounded ends, and lameness is usual. Here the line is fading and the dog is doing well.
B. The plate is too rigid and prevents healing: it must be removed now
Removing the plate before healing risks refracture. The rigidity of the compression plate is precisely what allows this type of healing.
C. It is delayed union and a cancellous bone graft should be added
There is no evidence of delay: clinical and radiographic progress is favourable. Grafting is reserved for fractures with poor biology or defects.
D. This is the expected course: with anatomical reduction and absolute stability bone heals by primary healing, without callus
Correct. In primary (direct) healing, osteons cross the fracture and the line gradually disappears without callus formation. Activity restriction continues and the dog is rechecked until healing is complete.
lightbulb Key takeaway
Absolute stability (compression) → primary healing without callus; relative stability (pin, fixator, bridging plate) → secondary healing with callus. Abundant callus under a compression plate indicates movement at the fracture and calls for checking the fixation.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.