THE BASICS:
Rupture of the cruciate ligament is the most common rear limb
injury of dogs.
There are 2 cruciate ligaments; the CRANIAL (or Anterior) and CAUDLE
(or Posterior).
The cranial cruciate ligament (CCL or ACL) is the most susceptible
to tearing.
There are also two small cushions in the knee joint called
menisci. Occasionally these may tear also. A meniscal tear is
very painful.
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CLINICAL
SIGNS:
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| In an acute injury, most dogs will be leg carrying lame.
They may toe touch, but usually will not use the leg. |
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| Sometimes the ligament will only be torn partially.
These dogs will have less obvious signs. It in not uncommon
for partial tears to not be noticed until they completely tear at a
later date. |
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There may be cases where the initial tear occurred during a
period that the dog was not observed. If the injury is not
noticed immediately there will be time for some healing to occur and
the injury may be seen as a persistent limp.
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DIAGNOSIS:
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Diagnosis is made based on orthopedic examination and
radiographs.
Orthopedic examination will usually show instability of the
joint, exhibited by cranial motion of the tibia in relation to the
femur. This called a positive "Cranial Drawer Sign"
or "Tibial Compression Test".
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| Radiographs are performed to evaluate for signs of
CCL, such
as the "fat pat sign" seen because of joint
effusion. The joint is also evaluated for evidence of
degenerative joint disease (DJD) or arthritis. There may be
DJD because the tear began as a partial that was not recognized, or
if there is concurrent disease in the joint such as a patella
luxation. |
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In humans, an MRI is performed to
evaluate the cruciate ligaments.
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| TREATMENT:
Surgical correction if the best option in most cases.
There are several different procedures developed that may be used in
the repair. This is evidence to the fact there is not one
ideal solution at this time.
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Most surgeons choose a combination of implant and soft tissue
reconstruction. With the main goal of cleaning debris from the
torn ligament, evaluating and repairing and damaged menisci, and stabilization of the joint to allow healing to
occur. Recently a newer procedure called a TPLO is showing
promise for the larger breeds of dogs.
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| Drugs such as Rimadyl®
can be given to decrease inflammation. These drugs are often
included in the rehabilitation of the knee after surgery as
well. If there has been damage to the cartilage, menisci, or
there is already DJD, chondroprotective agents such as Cosequin®
may be prescribed |
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