LC22_1 - Hanging of the patella
Synonyms
Dorsal dislocation of the patella
Name of the disease in English
Patellar dislocation
The disease in brief
During walking, the kneecap slides over the femoral trochlea, allowing flexion and then extension of the limb. The patella can get stuck on the top of the trochlea; the limb is blocked by the hyperextension of the stifle joint. The problem at the beginning is only a stiffness of the limb, then the hooking appears intermittently; finally it becomes permanent.
We see it appearing on adult cattle, old dairy women; it would also occur on young working cattle in India.
Clinic & diagnosis
When a pelvic limb stiffens intermittently while walking through the hyperextension of the stifle, one can suspect a hanging of the kneecap; palpation of the stifle then shows hypertensive tibio-patellar ligaments and a patella blocked at the top of the trochlea, most often in the medial region.
Typical sign of the disease
No description
Pictures
See below
Diagnostic formulas
No description
Differential diagnosis
- Spastic paresis of the gastrocnemius N260
- Spastic paresis of the femoral quadriceps N259
Confirm a suspicion?
No confirmatory method other than palpation of the tibio-patellar ligaments strained to the extreme, as well as the immediate result of the treatment
Prognosis and treatment
If hooking occurs on young, resting in pasture may lead to healing.
In adult cattle, a medial patellar desmotomy involves cutting the median tibio-patellar ligament near the tibia. The operation is performed standing up, after light sedation. By pulling the skin of the stifle outwards, the surgical site is shaved and disinfected.
Prevention
No specific prevention for adult cattle
References
Cattle Lameness Greenough PR Mac Callum F.J. Weaver AD ED The Veterinary Point-1983 p 282
