Friday 26th Jul, 2019
With Marley the priority was to perform X-rays in flexion to assess the stability of the patella fracture under tension.
The flexed image showed the fracture to be relatively stable, and non-distractible, suggesting this fracture did not require surgical intervention. Marley was strictly rested and NSAIDs given for the first 2 weeks.
Follow up X-rays performed after 4 weeks also showed the fracture gap to be closing suggesting the fracture was stable and healing, albeit slowly. The swelling which had been present on the front of the knee had decreased significantly. There was no lameness present at the time of recheck.
The patella is a sesamoid bone located between the quadriceps muscle and the patellar tendon that withstands large amounts of force during flexion and extension of the knee.
Patellar fractures are rare in small animals and are a consequence of direct trauma to the patella in most cases. In cats, patellar stress fractures are well known specifically in association with KaTS (Knees and Teeth Syndrome). Further info on Kats available here.
While bipartite patella is recognised to occur in humans and cats, it is poorly described in dogs, yet it is likely it can occur in some individual dogs, where there may be several secondary ossification centres and hence bipartite patella can occur. Perhaps this was a bipartite patella?
In Marley’s case however most likely the fracture was caused by trauma, and the fibrous tissue around the patella retained the patella within its ‘sleeve’.
The good news was that Marley made a full recovery, with strict rest and no need for any surgery or intervention – good stuff!