Cat Maine Coon Male castrated 10 years of age. Presented for bilateral plantigrade posture, The clinician was looking for signs of possible trauma, neurological or metabolic problem. Radiographs of the tarsal regions were taken. Radiographic findings and diagnosis Craniocaudal and mediolateral view centred on the right tarsus. Radiographic findings and diagnosis
- There is a solid and smooth defined new bone proliferation with elongation of the tuber calcanei extending proximally and cranially (arrows).
- The soft tissue swelling along the caudal border of the tibia have an irregular border with a marked identation (arrowhead) at the level of the distal third of the tibia.
- The described soft tissue have a heterogenous radioopacity with visibility of the fat tissue corresponding to the fascial plane. The fascial plane, distally, is deviated cranially and is in contact to the proximal margin of the new bone proliferation (small arrows).
- The same radiographic changes were present with similar degree on the contralateral limb.
Radiographic findings and diagnosis
- The radiographic diagnosis was bilateral chronic enthesiophytosis of the dorsoproximal tuber calcanei.
- Soft tissue findings are compatible with tendinopathy of the calcaneal tendon, as well most likely chronic.
- Differential diagnosis includes old avulsion fractures of the calcaneal tendon insertion on the tuber calcanei.
Comments
- To assess the appearance of the calcaneal tendon an ultrasound examination was performed (the conjoint tendon had heterogenous appearance, all in all of decreased echogenicity). A focal fluid collection was visible, compatible with edema or hemorrhage/hematoma formation.
- The common calcaneal tendon (Achille‘s tendon) is the convergence of 3 musculotendinous units at the calcaneus: the gastrocnemius tendon, the superficial digital flexor tendon and the common tendons (conjoined )of the biceps femoris, gracilis and semitendinous muscle.
- Injury with avulsion of origin of one or more head of the gastrocnemius may be radiographically visible as displacement of the fabella/e.
- The most common area for tendon rupture along the lenght in small animales is within 2 to 6cm of the calcaneal insertion. This is also the area of tendon with the poorest blood supply and then the least likely to heal primarily.
- Bilateral ruptures may occur in cases of severe trauma or as a result of degenerative tendon pathology.
- Chronic calcaneal tendonitis may be visible on radiographs with roughening or mineralised opacities at the proximal border of the calcaneus., representing small avulsion fragments or dystrophic mineralisations of the soft tissues.
- A surgical approach was elected and the cat underwent to surgery, with fixation as shown in the post operative radiographs.
Post operative cranio caudal and mediolateral radiographs of the right tarsus. Similar implant was applied on the left limb.
