Health & Medical

He came round the corner into the kitchen at speed, hit the tiles, and one back leg went out sideways. He yelped once and then he was up again, three-legged, holding the foot off the ground and looking at me like I had done something.

That was a torn cruciate ligament, and it happened in less than a second on a floor he had crossed ten thousand times.

The cruciate ligaments sit inside the knee, crossing over each other, and they stop the joint sliding back and forth. In dogs it is nearly always the cranial one that fails. In people this is the sports injury you hear about on the news, a violent twist in a footballer. In dogs it is usually not violent at all. The ligament has often been quietly degenerating for months, fibres fraying, until an ordinary movement finishes it off. That is why it happens on kitchen floors and getting out of cars rather than during dramatic chases.

Certain dogs are set up for it. Labradors, rottweilers, staffies, and any dog carrying extra weight. Steep-angled back legs are a factor. And once one side has gone, the other side has a meaningful chance of following within a couple of years, because whatever weakened the first ligament is usually present in both.

What it looks like from the outside

Sudden lameness on a back leg with no obvious wound is the classic. Some dogs are non-weight-bearing at first and then start using the leg again within days, which is where owners relax and where the damage continues. A partial tear presents as an on-and-off limp, worse after exercise, better after rest, and it can drag on for weeks while everyone assumes he pulled something.

The other sign is sitting oddly. A dog with a bad knee sits with that leg stuck out to the side rather than folded under, because folding it hurts. I noticed this in photographs afterwards, months before the tear, and did nothing about it.

The vet diagnoses it by feel. There is a specific test where the two halves of the joint are pushed against each other to see whether they slide, called the drawer test, and a positive result is close to conclusive. Many dogs need sedation for it because a painful knee tenses up. X-rays do not show ligaments but they show arthritis and rule out other things, and some vets go on to arthroscopy.

Then there is the decision, and it is a real one.

Surgery is the standard recommendation for medium and large dogs. The commonest operations change the geometry of the top of the tibia so the joint no longer needs the ligament, and they work well, with most dogs back to good function in a few months. It is not cheap. In the UK you are looking at a four-figure sum per knee, more at a referral practice, which is the single best argument for insurance I know of. Get quotes and ask specifically which technique your surgeon uses and how many they do a year.

Conservative management is a genuine option for small dogs, under about fifteen kilos, and for dogs who cannot have anaesthetic. It means strict rest for six to eight weeks, lead walks only, weight loss if there is any spare, pain relief, and physiotherapy. Scar tissue stabilises the joint over time. It is slower, the outcome is less predictable, and arthritis is more likely, but plenty of small dogs do well and it is not a cop-out.

What is not an option is carrying on as normal. An unstable knee grinds, the cartilage wears, the meniscus tears, and arthritis sets in permanently within months. A dog limping intermittently for a year has a joint that will never be right again regardless of what you do afterwards.

The recovery is where owners underestimate the commitment. Ours was eight weeks of lead-only toilet trips in the garden, no stairs, no jumping in the car, no other dogs, no games. He was a two-year-old collie cross. It was the longest two months of my life and I resorted to scent games on the kitchen floor and a great deal of frozen food in a rubber toy to keep him sane. Rushing this is how people end up back in surgery.

Physio genuinely helps. A qualified canine physiotherapist gave us five exercises that took ten minutes a day, and the difference in how he loaded that leg by week six was obvious even to me. Hydrotherapy afterwards built the muscle back. That is a cost on top of the surgery and it is the part I would least want to skip.

Afterwards, weight is the whole game. Every extra kilo goes through both knees, and a slim dog with one repaired cruciate can live a completely ordinary life. He is six now, runs, swims, and the other knee has held so far. I have put down rubber runners along the kitchen and the hall, which look terrible and cost eleven pounds, and I do not care.