Cruciate Ligament Repair

D E F I N I T I O N

Cruciate ligament repair may be required if the cranial, caudal or both cruciate ligaments are damaged.

These ligaments are tough, fibrous bands of tissue connecting the Femur and Tibia. They prevent the Stifle (knee) joint over-extending or rotating, and stop the Tibia moving forward relative to the Femur (Fitzpatrick Referrals, 2023).

Depending on the severity of injury, the joint may become unstable and require repair. There are four grades of cruciate ligament injury:

• Grade 1 – A minimal sprain or tear
• Grade 2 – A partial tear
• Grade 3 – Complete rupture
• Grade 4 – Rupture with small pieces of bone being taken

Grade 1-2 sprains can improve with rest, which must be taken seriously as grade 1 can easily become grade 2 with another twist.

Grade 3-4 requires surgery (Canine Massage Therapy Centre, 2023). This is more common for dogs weighing more than 15kg as they are less likely to heal well using non-surgical management.

Those weighing less than 15kg have a better chance, however repair takes a long time and is often not completely successful. Surgical repair replaces the ligament or alters how the knee works so that the ligament is not required.

In these surgeries, the Tibia is cut and fixed into a new position (Fitzpatrick Referrals, 2023). In TPLO (Tibial Plateau Levelling Osteotomy) surgery, the abnormal slope of the Tibia is reduced while in TTA (Tibial Tuberosity Advancement) surgery, the angle of the Patella tendon is changed to reduce tibial thrust when weight-bearing on the affected joint (Pet Health Hospital, 2023).

C A U S E S

Damage to the ligaments can occur due to weakening over time, or sudden injury such as a fall or twist causing complete rupture (PDSA, 2023).

For dogs, rupture of a ligament is more likely due to long-term degeneration which can be likened to that of a rope fraying over time; or changes to the bones of the Stifle (knee) joint due to osteoarthritis.

Factors affecting degeneration include environmental and genetic. Certain breeds have a genetic predisposition to cruciate injury and although the reasons for this are not certain, many will require cruciate ligament repair on both knees while still relatively young.

Genetically predisposed breeds include Newfoundlands, Boxers, Labradors, Rottweilers and West Highland White Terriers (Fitzpatrick Referrals, 2023).

Other factors influencing cruciate ligament stability are activities that involve landing, braking and twisting such as ball chasers and frisbee, slippery floors, landing incorrectly from a jump, hormonal imbalance, obesity and trauma (Canine Massage Therapy Centre, 2023).

S Y M P T O M S

Symptoms of injury to the cruciate ligament can vary from a slight limp to being completely unable to weight bear. There may also be other noticeable symptoms that often appear suddenly including:

• Pain in the back legs
• Swelling in one or both knees
• Stiffness when getting up or laying down
• Walking with an unusual gait