Carpal hyperextension in dogs

Carpal hyperextension is when a dog's wrist (the carpus) bends too far backwards because the tough supporting tissue on the back of the joint has torn or worn out. Instead of standing up on their toes, an affected dog's wrist sinks towards the ground, so the lower front leg looks flattened when they put weight on it. It is usually caused by a fall or jump in active dogs, or by gradual wear in older dogs.

It is not the same as a simple sprain. Once the supporting tissue has failed, it does not tighten back up on its own, so most cases need veterinary treatment to keep the wrist stable and comfortable. The good news is that with the right treatment, many dogs return to an active life.

Supporting Your Dog's Joints: How the Options Compare

Carpal hyperextension needs veterinary treatment, but the rest of your dog's joints matter too, because they take extra strain while one wrist is injured or healing.

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Understanding the Carpus

The carpus is the joint between the forearm and the front paw, the equivalent of your wrist. Animal Surgical Center describes it as seven small bones forming three joints, held together by strong ligaments and a tough pad of tissue on the palm side called the palmar fibrocartilage. This structure acts like a sling, stopping the wrist from bending too far back each time the front feet hit the ground.

Dogs carry more of their weight on their front legs than their back legs, and the wrists absorb a great deal of force when landing from a jump. When the palmar fibrocartilage and ligaments tear, that sling fails and the wrist collapses under load. WikiVet describes carpal hyperextension as a third degree (the most severe) sprain of the carpus.

Other Wrist Problems

Carpal hyperextension is different from carpal laxity in puppies, where young dogs' wrists are temporarily weak or over-bent while they grow, and from carpal valgus, where the paw turns outwards. Our guides to carpal laxity in puppies and carpal valgus in dogs cover those conditions.

What Causes Carpal Hyperextension

Fitzpatrick Referrals describes three forms of the condition:

• Traumatic. The most common form. WikiVet notes it is most often seen in large, young dogs after trauma such as jumping from a height. VCA Hospitals explains that when a dog falls and lands mainly on their front legs, the force can bend the wrist further than normal and tear the stabilising ligaments. Animal Surgical Center adds that it can follow a single fall or repeated jumps, for example out of vehicles or off decking.
• Degenerative. In older dogs, the supporting tissues can gradually weaken and stretch until the wrist sinks, often in both front legs. Fitzpatrick Referrals notes this is especially common in Collie breeds, and VCA Hospitals describes the degenerative form as most common in large breed dogs.
• Developmental. Some puppies have weak supporting ligaments as they grow, occasionally after prolonged bandaging. Many of these cases improve with time and correct nutrition, as our puppy carpal laxity guide explains.

Large, active dogs are most at risk of the traumatic form, but Fitzpatrick Referrals notes that small breeds can be affected too.

Recognising the Signs

After an injury, the signs are often obvious. With the degenerative form, they creep in so slowly that owners may not notice until the wrists have dropped a long way.

• Lameness on a front leg, which Animal Surgical Center notes tends to get worse with activity
• Swelling or thickening around the wrist
• The wrist sinking towards the ground when your dog stands or walks, so the lower leg looks flat
• A changed gait, with the front feet slapping or paddling
• Reluctance to jump, play or go on longer walks
• Sore or thickened skin on the back of the wrist, as VCA Hospitals notes pressure sores can develop where the carpus touches the ground

Some dogs with mild degenerative changes carry on fairly normally with an altered gait, while others are clearly uncomfortable. If you are unsure whether a front leg problem is a sprain or something more, our guide to sprains in dogs explains the difference.

How Vets Diagnose It

Your vet will watch your dog stand and walk, feel the wrist for swelling, pain and instability, and compare it with the other side. The key test is X-rays, including what are called stressed views. Fitzpatrick Referrals explains that this means X-raying the wrist in the position that truly reflects the extent of the hyperextension, and WikiVet notes these can often be taken with the dog standing and putting weight on the leg. Stressed views show exactly which of the three joint levels is unstable, which guides treatment. VCA Hospitals notes CT or MRI may sometimes be recommended.

Treatment Options

Splints, Bandages and Supports

Fitzpatrick Referrals lists supportive splints or bandages, physiotherapy and customised carpal supports as conservative options, and VCA Hospitals suggests splints and physical therapy may suit mild cases. For complete tears of the palmar fibrocartilage, though, Animal Surgical Center reports that splinting or casting is consistently ineffective in nearly all cases, because the torn tissue does not regain its strength. A custom-made support may still help some older dogs with the degenerative form, or dogs who are not suitable for surgery, and your vet or a canine physiotherapist can advise.

Carpal Arthrodesis (Surgical Fusion)

WikiVet describes pancarpal arthrodesis as the treatment of choice. The surgeon removes the cartilage from the wrist joints, packs them with bone graft and fixes them with a plate and screws, so the wrist heals into one solid, stable unit. If only the lower joints are unstable, a partial carpal arthrodesis can fuse just those levels, although WikiVet notes this is less successful and associated with later degenerative joint disease. Our article on dog joint surgery explains what to expect around an operation.

Dogs walk well on a fused wrist because the carpus mainly moves in one direction anyway. Animal Surgical Center reports that about 90 to 95% of patients respond well to surgery, though a fully fused wrist may give a noticeable change in gait. In a small UK study of working dogs by Higgins and Hayes (2024), 9 of 10 owners were satisfied or very satisfied with the result of pancarpal arthrodesis, and 9 of 10 dogs went back to all or most of their normal duties.

Recovery and Rehabilitation

Rest is the hardest part for most owners. Keep your dog in a small, safe area, use non-slip mats on hard floors, keep the splint clean and dry, and never let them jump on or off furniture or out of the car. Once your vet gives the go-ahead, a structured rehabilitation plan helps rebuild muscle in the injured leg. Our guide to canine physiotherapy explains what sessions involve.

Supporting the Other Joints

While one front leg is splinted or sore, your dog shifts weight onto the opposite front leg, the back legs and the spine. That extra load can make existing arthritis in those joints flare up, and the degenerative form often affects both wrists anyway. Keeping your dog lean is the single biggest help, since every extra kilo is carried mostly on the front end.

A daily joint supplement can add nutritional support for the joints doing the extra work. MedPaw Hip & Joint Chews Max is a soft chew complementary feed containing glucosamine, chondroitin, MSM, green-lipped mussel, hyaluronic acid and Boswellia serrata, with omega-3 from green-lipped mussel and flax seed, plus vitamins C and E and zinc. Give 1 chew a day up to 4kg, 2 for 5 to 17kg, and 2 to 3 for 18kg and over, doubled for the first three weeks, and allow 2 to 3 months for optimal results. It supports joints alongside your vet's treatment but does not repair a torn ligament, so check with your vet first if your dog is having surgery or is on any medication.

Can It Be Prevented?

You cannot prevent every accident, but you can reduce the risk of the traumatic form:

• Use a ramp or lift larger dogs in and out of the car and vans rather than letting them jump down.
• Discourage leaping off decking, walls and high furniture.
• Build fitness gradually before strenuous activity, especially for working and sporting dogs.
• Keep your dog at a healthy weight to reduce load on the front legs.
• Check older dogs' front feet and wrists regularly, especially Collie breeds, so gradual sinking is spotted early.

When to See Your Vet

• The same day: if your dog is lame on a front leg after a fall or jump, or the wrist looks swollen or is sinking
• Within a few days: if you notice one or both wrists gradually dropping, or a change in how your dog's front feet land
• Promptly during recovery: if a splint slips, gets wet, smells, or your dog chews at it or seems more lame
• Urgently: if your dog will not put any weight on a leg or seems to be in a lot of pain