Hip Dysplasia with the Shih Tzu Breed

Hip dysplasia is a condition that Shih Tzu owners should be aware of. It is a complex condition affecting a dog's hip joint and socket, involving various anatomical components crucial for mobility. The condition arises from abnormalities in the structure and function of the hip joint, which includes the following aspects:

1. Abnormal Joint Structure: In a healthy dog, the head of the femur (thigh bone) fits snugly into the hip socket (acetabulum). However, in hip dysplasia, this fit is compromised. This could be due to the femoral head not sitting properly in the socket, the presence of bone spurs that hinder correct positioning, or a mismatch in size between the femur head and the socket.
2. Weakened Support Structures: The stability of the hip joint is maintained by connective tissues, muscles, and ligaments surrounding it. Hip dysplasia often involves a weakening of these support structures, leading to joint instability. This weakening can contribute to or exacerbate the joint misalignment.
3. Subluxation: A key feature of hip dysplasia is subluxation, where there is partial dislocation in the hip joint. This occurs when the two bones that form the joint—the femur and the pelvis—do not maintain their proper alignment, often leading to pain and mobility issues.

It's important to note that hip dysplasia can affect one or both hips in a Shih Tzu. In many cases, even if symptoms are initially apparent in only one hip, the Shih Tzu’s other hip may also be affected to some degree, either at the same time or later. 

The severity of the condition can vary, and the progression of symptoms can be influenced by factors such as a Shih Tzu’s size, weight, age, and overall health. Early detection and intervention can play a critical role in managing the condition and maintaining a Shih Tzu’s quality of life.

Occurrence Rate of Hip dysplasia with Shih Tzu Dogs 

Ranking: You may be wondering how common it is for a Shih Tzu to have hip dysplasia or what are the chances of it developing. The Orthopedic Foundation of Animals (OFA), which tracks the indecent rates of several diseases and conditions, analyzed the incident rate of hip dysplasia in 209 different dog breeds. Of those 209 distinct breeds, the Shih Tzu ranks at #41. 

Overall (since OFA has kept track of this), 1141 Shih Tzu dogs were evaluated, 21.9% were found to have some level of hip dysplasia, while 75.5% did not. This said, their most recent evaluations, involved 24 Shih Tzu dogs. Of those 24, 16.7% were found to be dysplastic. 

A #41 ranking suggests a moderate level of risk for hip dysplasia with the Shih Tzu breed. It's substantial enough to warrant attention but not so high as to be a predominant concern as in some larger breeds.

• Implications for Breeders and Owners: For breeders, this ranking underscores the importance of selective breeding practices and health screenings. 
• Considerations for Prospective Owners: People considering adopting a Shih Tzu should be aware of this risk. While it's not a guarantee that a Shih Tzu will develop hip dysplasia, it's a significant enough probability to consider in their pet's long-term health planning.
• Considerations for Owners: For pet parents, it means being proactive in monitoring for symptoms and engaging in preventive care, such as maintaining an appropriate weight and providing joint-supportive nutrition.
  

Age of Onset

Most Shih Tzu dogs are diagnosed with hip dysplasia between 6 months old to 1 year old. Though it has been seen occasionally with puppies as young 4 months old and adults 2+ years old.

Causes of Hip Dysplasia in Shih Tzu Dogs

Hip dysplasia in the Shih Tzu breed is primarily a genetic condition, but its onset and severity can be influenced by environmental factors. These include trauma to the hip area, excessive or improper exercise, and obesity, which places extra strain on the joints. Additionally, rapid growth during puppyhood and malnutrition can also contribute to the development of this condition.

Symptoms of Hip Dysplasia in Shih Tzu Dogs

• Lameness in Hind Legs: A Shih Tzu may show reluctance or inability to use one or both of their hind legs normally.
• Altered Gait: The affected Shih Tzu may limp or exhibit a ‘bunny hop’ gait.
• Discomfort: Signs of pain or unease, especially when the hips are touched or moved.
• Narrow Stance: The dog may hold its rear legs unusually close together.
• Muscle Loss: A noticeable decrease in muscle tone around the hip area.
• Mobility Challenges: Difficulty in rising, climbing stairs, or jumping.
  

Diagnosing Hip Dysplasia in Shih Tzu Dogs

OFA: Diagnosing hip dysplasia typically involves a physical exam and x-rays, with the Orthopedic Foundation for Animals (OFA) providing a standardized assessment recognized by the AKC. X-rays, taken under specific guidelines by a licensed veterinarian, are submitted to the OFA for evaluation.

Diagnosis is more challenging in dogs under 2 years old, hence OFA does not evaluate puppies, though preliminary assessments are done. Females in heat are not tested; it's scheduled around their heat cycle.

To ensure accurate x-ray evaluation, dogs are usually given anesthesia or muscle-relaxing medication for stillness. The x-rays are reviewed by three radiologists, and a consensus score is given based on hip conformation compared to similar breeds and age groups. Hips are classified as normal (excellent, good, fair), borderline dysplastic, or dysplastic (mild, moderate, severe). Dogs with borderline or dysplastic scores are not cleared for breeding.

The process, from submission to results, takes about two weeks. Dogs passing the test receive an OFA certificate, indicating they are free from this genetic condition. When considering buying a Shih Tzu puppy, you'll want to ensure both parents have OFA certification.

PennHIP Method: The University of Pennsylvania Hip Improvement Program (PennHIP) employs a different diagnostic approach using distraction/compression x-ray views to measure joint laxity. But with this, sedation is mandatory for the dog to ensure accurate x-ray imaging. The process involves two x-ray views with the hind limbs in a neutral position, maximizing joint laxity visibility. Joint laxity is measured on a scale from 0 to 1, where 0 signifies a very tight joint and 1 indicates complete luxation with minimal femoral head coverage. The cost for the PennHIP test ranges from $200 to $400.

Comparing Tests: The OFA method does not require anesthesia and provides accurate evaluations with fewer x-ray views (one view as opposed to three in PennHIP). Additionally, it is recognized by the AKC and is less expensive. These factors make OFA the preferred choice for many, despite the different diagnostic focuses of the two tests.

Hip Screening and OFA Grade Classifications

• Excellent: Superior hip conformation with a deeply seated femoral head in a well-formed acetabulum and minimal joint space.
• Good: Slightly less than excellent, but showing a well-formed, congruent hip joint with the femoral head fitting well into the socket.
• Fair: Some irregularities present; wider hip joint with minor slipping of the femoral head out of the acetabulum, which may appear slightly shallow.
• Borderline: Ambiguous results, showing more incongruity than fair-rated hips but lacking definitive arthritic changes for a dysplasia diagnosis.
• Mild Dysplasia: Noticeable subluxation with the femoral head partially out of a shallow acetabulum, leading to increased joint space.
• Moderate Dysplasia: Minimal seating of the femoral head in a shallow socket, with arthritic changes like femoral and acetabular remodeling, osteophytes, and trabecular bone changes.
• Severe Dysplasia: Pronounced dysplasia signs with the femoral head partly or completely out of a shallow socket and significant arthritic alterations.

Understanding these aspects of hip dysplasia in Shih Tzu dogs is crucial for early detection, appropriate care, and management of this condition, helping to ensure the well-being and quality of life for these dogs.

Non-Surgical Treatment Options

Managing hip dysplasia in Shih Tzu dogs involves a combination of lifestyle modifications, medical management, and potentially surgical interventions, depending on the severity of the condition.

1. Weight Management: Maintaining an optimal weight is crucial. Excess weight can exacerbate hip dysplasia symptoms by increasing stress on the joints.
2. Exercise Regulation: Gentle, low-impact exercises like swimming or short walks can help maintain muscle strength without putting too much strain on the hips.
3. Physical Therapy: Physical therapy, including specific exercises and massage, can improve joint mobility and strengthen the muscles around the hip.
4. Joint Supplements: Supplements such as glucosamine and chondroitin can be beneficial. They help maintain cartilage health and joint fluidity.
5. Anti-Inflammatory Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) may be prescribed to reduce pain and inflammation. Always use medications as directed by a veterinarian, as certain drugs can have side effects.
6. Orthopedic Beds: Using an orthopedic dog bed can provide better support for a Shih Tzu with hip dysplasia, helping to alleviate pain during rest.
7. Environmental Modifications: Making adjustments at home, like providing ramps to avoid stairs or steps, can help a Shih Tzu with hip dysplasia move around more comfortably.
   

Surgical Treatment Options

The majority of cases of hip dysplasia can be improved with non-surgical treatment. Surgical intervention may be considered in cases where non-surgical treatments are not sufficiently effective in managing pain and improving a dog's quality of life. There are three main options:

1. Triple Pelvic Osteotomy (TPO): Suitable for younger dogs, this surgery involves cutting and repositioning the bones to achieve a better fit of the femoral head in the acetabulum.
2. Femoral Head Ostectomy (FHO): This procedure involves removing the femoral head to alleviate pain. It is often considered for smaller breeds like Shih Tzus, where the resulting scar tissue can create a pseudo-joint.
3. Total Hip Replacement (THR): This is the most comprehensive surgical option, where the entire hip joint is replaced with prosthetics. It is usually reserved for severe cases and can significantly improve the quality of life.