Cruciate Ligament Injury in Dogs: Signs, Surgery and Recovery

The cranial cruciate ligament sits inside the stifle — the dog’s knee — and stops the shin bone sliding forward relative to the thigh bone. When it fails, the joint becomes unstable, and every step grinds surfaces that were never meant to move that way.

It is the single most common orthopaedic problem vets see in dogs, and the single most common reason for orthopaedic surgery.

It usually is not a sporting injury

In people, the equivalent ligament tears suddenly during sport. In dogs, that pattern is the exception.

Most canine cruciate disease is degenerative. The ligament weakens gradually over months or years, fraying under load, until a partial tear becomes a complete one. The dramatic moment when the dog yelps chasing a ball is often the final failure of a ligament that was already seventy per cent gone.

This matters for two reasons. First, it explains why dogs frequently do the other side within a year or two — the process was never limited to one leg. Second, it means the underlying risk factors are worth taking seriously.

Risk factors:

• Being overweight. The strongest modifiable factor by a distance.
• Breed. Labradors, Rottweilers, Newfoundlands, Staffordshire Bull Terriers and West Highland White Terriers are over-represented.
• Conformation, particularly a steep angle to the top of the shin bone.
• Early neutering in some large breeds, where it alters growth and joint angles.
• Weekend-warrior exercise: sedentary all week, flat out on Saturday.

Signs

Sudden complete rupture: the dog cries out, stops, and holds the leg up entirely. It may start toe-touching within a few days, which owners often read as improvement.

Partial or degenerative tear: intermittent hind-leg lameness that comes and goes, stiffness after rest, sitting with the leg out to one side instead of tucked, reluctance to jump into the car, and a gradual loss of muscle on the affected thigh.

Diagnosis

Your vet will feel for instability in the joint — the cranial drawer test and tibial compression test — often under sedation, because a tense dog can mask movement. X-rays show joint swelling, arthritis and the bone angles needed for surgical planning, though they do not show the ligament itself.

Surgical options

Several techniques exist and vets genuinely disagree about which is best for which dog. In broad terms:

TPLO (tibial plateau levelling osteotomy). The top of the shin bone is cut and rotated to change the joint’s mechanics so the ligament is no longer needed for stability. Widely used in medium and large dogs, with good long-term function and a substantial body of evidence behind it.

TTA (tibial tuberosity advancement). A different geometric solution to the same problem, moving the attachment point of the patellar tendon forward.

Extracapsular repair (lateral suture). A strong suture outside the joint mimics the ligament while scar tissue stabilises the knee. Less invasive and cheaper; generally reserved for smaller or less active dogs, where results are good.

Conservative management. Rest, weight loss, pain relief and physiotherapy without surgery. It can work for small dogs and for those where anaesthesia is too risky, but larger dogs managed conservatively usually end up with worse function and more arthritis.

Your surgeon’s recommendation will weigh your dog’s size, age, activity, conformation and the state of the joint. Ask what they do most and why — surgeon experience with a particular technique matters as much as the technique.

The recovery is the hard part

This is what owners underestimate. Regardless of technique, recovery means eight to twelve weeks of strictly controlled activity.

Typical stages:

1. Weeks 1–2. Crate or pen rest. Lead-only toilet breaks, a few minutes at a time. Pain relief. Incision checks.
2. Weeks 3–6. Short controlled lead walks, building gradually. Gentle physiotherapy exercises if prescribed.
3. Weeks 6–10. Longer lead walks, adding gentle slopes. Follow-up X-rays for bone-cutting procedures.
4. Weeks 10–16. Gradual return to off-lead activity, if cleared.

No stairs, no jumping, no sofas, no slippery floors, no running, and no free access to the garden. This is the part that determines the result.

Keeping a confined dog sane

Mental work substitutes for physical work surprisingly well.

• Scatter part of the meal on a towel for nose work
• Lick mats and stuffed toys
• Short, calm training: chin rests, hand touches, nose targets — all done from a lying position
• Puzzle feeders on the floor, not requiring the dog to stand

Non-slip flooring

Slipping is how post-operative dogs re-injure themselves. Lay runners or yoga mats on every hard floor the dog crosses, including the route to the door.

The other leg

Studies suggest somewhere between forty and sixty per cent of dogs rupture the opposite cruciate within a couple of years. Weight control and sensible, consistent exercise are the main things you can do about it. If the second leg goes, the good news is you will already know exactly what recovery involves.

Long term

Most dogs return to full or near-full function after surgery. Arthritis in the joint is essentially inevitable, so long-term management typically includes weight control, regular moderate exercise, omega-3 supplementation and sometimes joint supplements or long-term pain relief.

This article is general information and not a substitute for the advice of the vet or surgeon who has examined your dog.