Sprains and Ligament Injuries in Dogs
The stifle joint is stabilized by a number of ligaments. The two large
ligaments that cross in the middle of the joint are the cranial and caudal
cruciates. The ligaments that stabilize the sides of the joints are the medial
and lateral collaterals. The meniscus is a cushion of cartilage between the
femur and the tibia and fibula.
Rupture of the cranial cruciate is a common and serious injury of the
stifle. It occurs in all breeds at all ages, but is more likely to occur in
younger, active dogs. There may be a congenital or developmental predisposition
in some dogs (see Osteochondrosis). If one tears, unless it is repaired, the
ligament in the other knee also eventually tears.
The sudden onset of rear leg lameness suggests a rupture. The lameness may
disappear with rest, then recur with exercise. In some cases the presenting
sign is persistent lameness in one or both hind legs. The diagnosis is
confirmed by palpating the stifle joint. In many cases the medial collateral
ligament is also damaged.
Rupture of the medial or lateral collateral ligament usually is caused by a
severe blow to the side of the joint or a twisting motion, especially at speed.
The affected ligament may be stretched, partially torn, or completely severed.
Diagnosis is made by manipulating the joint and looking for a degree of
looseness. Severe blows to the stifle may also cause joint fractures. Dogs may
need to be anesthetized for a thorough evaluation of the stifle.
Injuries to the meniscus are associated with injuries to the cruciates. If a
cruciate injury goes untreated, secondary damage to the meniscus occurs in the
weeks and months that follow. The end result is degenerative arthritis and
permanent lameness. Isolated meniscus injuries are rare in dogs.
Treatment: The treatment of choice for ruptured cruciate ligaments is
surgical repair. If this is not done, the joint becomes unstable and is subject
to further damage. Following surgical repair, physical therapy and restricted
exercise are important for successful recovery. The complete rehabilitation
program may take months for dogs to return to near full athletic performance
Collateral ligaments that have been stretched but not torn usually heal
satisfactorily with rest and restricted activity.