CONDITION

Legg-Calvé-Perthes Disease

Legg-Calvé-Perthes disease is a condition affecting small breed dogs where the blood supply to the femoral head (the ball of the hip joint) is disrupted, causing bone death and subsequent collapse, leading to pain, lameness, and hip dysfunction.

Why this matters now

Legg-Calvé-Perthes typically develops in young toy and small breed dogs between four and twelve months of age. Yorkshire Terriers, Miniature Poodles, Chihuahuas, West Highland White Terriers, and similar breeds face increased risk. The condition usually affects one hip, though bilateral cases occasionally occur.

The disease begins silently as blood supply to the femoral head becomes inadequate. Over weeks to months, bone cells die and the femoral head weakens and deforms. As the structural integrity fails, the bone collapses and the normal round shape of the hip joint is lost. This mechanical damage causes progressive pain and limb dysfunction.

Signals & patterns

Early signals

Subtle hind leg lameness

Slight favouring of one back leg that may initially be intermittent or easily missed.

Reduced activity levels

Decreased enthusiasm for play or exercise compared to typical puppy energy.

Licking at the hip area

Attention to the affected hip region may indicate developing discomfort.

Difficulty rising

Reluctance or hesitation when getting up from rest, particularly noticeable first thing in the morning.

Later signals

Obvious limping

Pronounced lameness with minimal weight-bearing on the affected leg during walking.

Leg carried or held up

Dogs may avoid using the leg entirely, carrying it off the ground.

Muscle wasting of the thigh

Visible reduction in muscle mass around the hip and thigh compared to the other leg.

Pain on hip manipulation

Vocalisation, flinching, or resistance when the hip joint is moved during examination.

Click to read about the biological mechanisms

How this is usually investigated

Assessment focuses on confirming the characteristic changes in the femoral head through imaging, while ruling out other causes of hip pain in young dogs.

Physical examination

Purpose: Identifies pain on hip extension and reduced range of motion
Considerations: Muscle wasting and leg length comparison provide additional information; may require sedation for thorough evaluation.

Hip radiography

Purpose: Reveals characteristic changes including bone death, collapse, and deformation
Considerations: Highly diagnostic in most cases; both hips imaged for comparison; serial radiographs show progression.

CT scan

Purpose: Provides detailed assessment of bone changes and joint congruity
Considerations: Requires anaesthesia; helpful for surgical planning; shows extent of damage precisely.

Blood tests

Purpose: Rules out systemic illness and assesses overall health before any procedures
Considerations: Results typically normal; helps ensure no concurrent conditions affecting treatment decisions.

Options & trade-offs

Management typically requires surgical intervention to address the painful, deformed joint, with different procedures offering various approaches to restoring comfortable mobility.

Femoral head and neck excision

Surgical removal of the damaged femoral head, allowing a false joint to form from scar tissue

Trade-offs: Most commonly performed; eliminates bone-on-bone pain; functional recovery usually excellent in small dogs; less predictable in larger patients.

Total hip replacement

Replacing the damaged joint with artificial components

Trade-offs: Restores more normal mechanics; requires specialist facilities; higher cost; excellent outcomes when successful; size limitations in very small dogs.

Conservative management

Pain relief, weight management, and physical therapy without surgery

Trade-offs: Rarely sufficient for complete lesions; may be considered for partial or early cases; ongoing discomfort likely with significant bone damage.

Physiotherapy and rehabilitation

Structured exercise programmes to maintain or restore muscle mass and joint function

Trade-offs: Essential adjunct to surgical treatment; supports recovery; requires commitment; professional guidance beneficial.

Pain management

Anti-inflammatory and analgesic medications to maintain comfort

Trade-offs: Provides relief during diagnosis and pre-surgical period; long-term medical management alone rarely adequate.

Common misconceptions

Misconception:

"Legg-Calvé-Perthes is the same as hip dysplasia"

Reality:

While both affect the hip, they are distinct conditions with different causes. Legg-Calvé-Perthes results from loss of blood supply, while hip dysplasia involves abnormal joint development and laxity.

Misconception:

"Small dogs can manage with the condition without treatment"

Reality:

The pain from a collapsed, deformed femoral head typically requires surgical intervention for comfortable mobility, even in small dogs.

Misconception:

"Removal of the femoral head leaves dogs unable to walk properly"

Reality:

Small dogs typically adapt remarkably well after femoral head excision, developing functional false joints that allow normal activities with minimal or no observable lameness.

Owners of young small breed dogs developing hind leg lameness may recognise the possibility of Legg-Calvé-Perthes disease, particularly in predisposed breeds. Understanding that early diagnosis and appropriate intervention typically lead to good functional outcomes can help frame discussions about assessment and management.

Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS