Osteochondrosis in dogs – symptoms and treatment

Overview

Osteochondrosis is a developmental joint disease particularly affecting medium-sized and large, rapidly growing dogs.

The shoulder is the most common site of osteochondrosis in dogs.

It also occurs in the elbow, knee and hock.

Less commonly, changes may also affect the vertebral endplates in the spine.

More than one joint may be affected in the same dog.

Not all osteochondrosis changes cause visible symptoms.

The outlook for the shoulder is generally better than for the knee or hock, so the location affects treatment goals.

Early detection and treatment may slow the development of osteoarthritis.

OCD with a cartilage flap is particularly associated with pain and impaired joint function.

Causes

Cartilage in a growing bone normally turns into bone, but in osteochondrosis this development is incomplete in a localised area.

The cartilage layer becomes abnormally thick, and its deepest cells may not receive enough nutrients.

As cells die, a weak area forms at the boundary between cartilage and bone.

Even ordinary daily activity can then cause a crack in the cartilage.

The crack may extend towards the joint and form a mobile cartilage flap.

A detached fragment may remain at the back of the joint, inside the joint capsule.

A calcifying fragment may enlarge into a loose body, sometimes called a joint mouse, visible on an X-ray.

Loose fragments and an uneven cartilage surface irritate the joint's inner lining.

This can lead to ongoing cartilage breakdown and progressive osteoarthritis.

Some loose fragments may attach to the joint capsule or gradually disappear through resorption.

No single precise cause is known; several factors contribute to the disease.

In the shoulder, the lesion is usually on the back surface of the humeral head.

In the knee, it may affect a femoral condyle.

In the hock, a common site is a ridge of the talus, one of the joint's bones.

Risk factors

Osteochondrosis has a polygenic inherited basis, involving several genes.

Rapid growth and overfeeding may promote the development of clinical disease.

Excess weight also plays a role in the development of symptomatic disease.

Excessive intake of energy or minerals is among the suspected predisposing factors.

Disrupted blood supply and hormonal factors are considered possible contributors.

Males are affected more often than females.

The disease is more common in certain breeds and family lines.

Heritability estimates of 0.25–0.40 have been reported.

This figure describes the genetic contribution to differences between dogs, rather than meaning that this proportion of all dogs will become affected.

Osteochondrosis can occur alongside elbow or hip dysplasia in the same dog.

However, environmental factors alone do not cause osteochondrosis without other susceptibility to the disease.

Typical symptoms

Shoulder symptoms often begin at 4–8 months of age.

OCD also typically occurs at 6–9 months of age.

Lameness from shoulder osteochondrosis is also seen across the wider age range of 3–9 months.

• A front or back leg is lame, depending on which joint is affected.

• Lameness improves with rest but worsens after exercise.

• Your dog holds the leg in an unusual position to avoid loading it.

• The joint swells or feels warm.

• The joint's normal range of movement decreases.

• In a severe case, your dog avoids putting weight on the painful leg.

Lameness may initially be mild and intermittent.

Pain may only become apparent when the joint is examined, even if there is little lameness at home.

Complications and consequences

Untreated OCD can cause large calcified loose bodies and osteoarthritis.

The outlook after treatment for shoulder osteochondrosis is generally excellent.

For the knee, the outlook varies and may be guarded.

For the elbow, the outlook is generally guarded.

Hock lesions have the poorest outlook of the affected joints.

Existing osteoarthritis and other joint diseases reduce the prospects for recovery.

Hock instability is another factor that worsens the outlook.

Shoulder symptoms beginning very early, at 4–5 months of age, are associated with a poorer outcome.

A large lesion and a large dog may also worsen the shoulder's outlook.

In severe cases, shoulder osteochondrosis may be associated with inflammation of the biceps tendon.

Possible surgical complications include wound infection and a collection of tissue fluid, called a seroma, at the operation site.

Osteoarthritis may develop in the shoulder even after successful treatment, but it does not always cause clinical signs.

Diagnosis at the vet

Clinical examination and imaging

The vet examines the lameness and painful joint before choosing suitable imaging.

When joints other than the shoulder are affected, conditions such as kneecap dislocation and hip or elbow dysplasia must be distinguished.

X-rays may show flattening of the joint surface and an area of reduced bone density beneath the cartilage.

They may also show bone spurs, increased joint fluid or loose fragments.

Both shoulders are imaged even if only one front leg appears to be affected.

An adequate assessment usually needs several images from different directions.

Sedation or a brief general anaesthetic makes correct positioning easier.

Open growth plates in a puppy under 6–7 months old can make X-ray interpretation more difficult.

CT shows the size and location of the bone defect beneath the cartilage, particularly in a joint that is difficult to assess with X-rays.

Arthroscopy allows direct assessment of cartilage from inside the joint.

Contrast imaging of the joint may help show the boundaries of a detached cartilage flap.

Joint ultrasound is sometimes also needed to help confirm the diagnosis.

Shoulder screening schemes

Some breed-club shoulder screening schemes have a minimum age of 12 months.

Shoulder X-rays taken before 12 months of age may be submitted as additional images for such an assessment.

In these schemes, 'OC not detected' indicates a rounded, even back edge of the humeral head.

'OC detected' indicates flattening or an area of reduced X-ray density on the back surface of the humeral head.

'OC inconclusive' indicates very mild or atypical changes in the humeral head or the shoulder blade's joint socket.

The overall official result is determined by the worse shoulder.

Some schemes accept CT performed at an approved imaging centre for an official assessment.

Under some scheme rules, CT supplementing the first X-ray assessment must be performed within three months of the X-rays.

An inconclusive screening assessment may lead to requests for additional images in different positions or repeat imaging later.

Treatment

Rest and surgery

The vet chooses treatment according to the extent of the lesion and the dog's symptoms.

A small cartilage fissure or very small flap in a dog under six months old may sometimes heal with strict rest.

In this situation, outings are limited to short lead walks and other activity is restricted.

The vet prescribes any medication needed for pain and inflammation.

Surgery is usually needed if lameness does not improve, the fragment is large or it becomes trapped between the joint surfaces.

Surgery removes the damaged cartilage flap or free fragment.

Treatment of the bone beneath the cartilage aims to initiate formation of repair fibrocartilage.

The procedure can be performed arthroscopically or by opening the joint.

Arthroscopy uses small openings, a camera and instruments inserted into the joint.

For a large or poorly healing cartilage defect, an osteochondral graft or an implant replacing the joint surface may be considered.

Rehabilitation and persistent pain management

During the first 2–3 weeks after surgery, outings may be restricted to short lead walks.

After about three weeks, controlled exercise may be increased according to the treatment plan.

At about six weeks, some dogs may progress to gentle jogging that remains controlled.

Guided passive movement exercises help maintain joint mobility.

Osteoarthritis care combines weight management, suitable exercise and pain relief as complementary measures.

Physiotherapy may include individual exercises and hydrotherapy.

Omega-3 fatty acids may help as supportive care for osteoarthritis.

Research findings on stem cell treatments are conflicting.

Regenerative treatments may offer little benefit in a very severely damaged joint.

Osteochondral grafts in selected cases

An osteochondral graft from a donor aims to replace the damaged area with a functioning joint surface.

A clinical study conducted in the United States and Canada treated various cartilage and bone defects.

For OCD lesions of the knee's medial femoral condyle, all ten treated joints achieved acceptable or full function.

The average follow-up period for these knees was 25.4 months.

For lateral femoral condyle lesions, seven of nine treated joints achieved acceptable or full function.

The average follow-up period for the lateral lesions was 16.8 months.

A small follow-up study of this kind does not establish that grafts are superior to other treatments.

In the osteochondral graft study, recovering dogs were restricted to lead exercise for eight weeks.

The poor outcomes in lateral condyle lesions involved damage to graft cartilage in both knees of the same dog.

Prevention

Keep a puppy lean, because excess weight influences the development of clinical osteochondrosis.

Excessive calcium or phosphorus intake is among the suspected predisposing factors.

However, balanced feeding does not remove inherited susceptibility.

Even a dog without symptoms can pass genes predisposing to osteochondrosis to their offspring.

Breeding is not recommended for a dog with diagnosed osteochondrosis in any joint.

Some breed-club rules permanently exclude dogs operated on for shoulder osteochondrosis from breeding.

Under these rules, the same exclusion applies to a shoulder screening result in which OC is detected.

Important for dog owners

Lameness in only one leg does not rule out changes in the opposite joint.

Healing of the surgical wound requires restricted activity as instructed by the vet.

Full activity is resumed gradually.

Mention even mild lameness if it recurs after exercise in a growing large dog.

Some official screening schemes require previous surgery affecting the shoulder to be reported to the vet performing the imaging.

In such schemes, an operated shoulder is marked as operated in the official assessment.

Record when lameness began, the effect of rest and any medication your dog receives. Ask for practical instruction in home exercises and agree when activity should increase during your own dog's recovery.

Under some screening rules, routine repeat official imaging is only permitted 12 months after the previous screening examination.

Some schemes do not issue a further X-ray assessment of the same shoulder examination after a CT assessment.

Frequently asked questions

Are OC and OCD the same condition?

OC means a developmental disorder of cartilage turning into bone. OCD is the form in which a separating flap develops in the damaged cartilage. Not all osteochondrosis changes cause visible symptoms, even if several joints are affected. OCD with a cartilage flap is particularly associated with pain and impaired function.

Can osteochondrosis heal with rest?

A small cartilage fissure or very small flap in a dog under six months old may heal with strict activity restriction. Persistent lameness or a large lesion often requires surgery. The vet assesses this according to the examination findings.

Is the outlook the same for shoulder and hock OCD?

No. The outlook for the shoulder is usually excellent, while the hock has the poorest outlook of the affected joints. Existing osteoarthritis and hock instability worsen recovery. The same expectations therefore do not apply to different joints. Early surgery generally improves the outlook.

Can a growing puppy be examined before the official shoulder screening age?

Yes. Clinical signs often begin at just 4–8 months of age. Some official screening schemes have a minimum age of 12 months. Earlier shoulder images may be submitted later as additional images for such an assessment. Young puppies' growth plates can complicate X-ray interpretation.

Can a dog that has had osteochondrosis be used for breeding?

Breeding is not recommended for a dog with diagnosed osteochondrosis, regardless of the affected joint. Some breed-club rules permanently exclude a dog with a positive shoulder screening result or previous osteochondrosis surgery from breeding. Even a dog without symptoms can pass on susceptibility. In such screening schemes, a shoulder operated on for osteochondrosis is marked as operated in the official assessment.