Mild, Moderate, Severe: The Hip Dysplasia Grades

The grade on your dog’s hip X-ray is not a sentence — it’s a starting point for understanding what’s happening in those joints and what to do about it.

What Is the OFA Grading System?

The Orthopedic Foundation for Animals evaluates hip X-rays submitted by veterinarians and assigns a standardized grade based on joint conformation, laxity (looseness), and any visible signs of degenerative joint disease like bone remodeling or arthritis. Three board-certified radiologists independently score each submission, and the final grade reflects the consensus of all three.

The OFA system uses seven classifications:

For breeding purposes, only dogs rated excellent, good, or fair receive OFA clearance. But for pet owners, the grades that matter most are the ones in the dysplastic range — mild, moderate, and severe — because those are the ones that shape your dog’s day-to-day care.

What Does Each Dysplastic Grade Look Like on X-Ray?

Each grade reflects a different degree of structural change inside the hip joint. Understanding what your vet is actually seeing helps you ask better questions.

Mild Hip Dysplasia

A mild grade means the femoral head (the ball) fits into the acetabulum (the socket) with only minor incongruency. There may be slight subluxation, meaning the ball is beginning to shift away from where it should sit, and early remodeling of the bone edges may be visible. Many dogs at this grade show no obvious symptoms, especially when young. That said, mild dysplasia is still dysplasia — without management, it can progress to moderate or severe over time.

Moderate Hip Dysplasia

A moderate grade shows more significant joint laxity. The femoral head has shifted noticeably, and there is usually visible evidence of secondary osteoarthritis developing — bone spurs, flattening of the femoral head, or a shallower socket. Dogs at this grade are more likely to show clinical signs: difficulty rising after rest, a shorter stride, reluctance to jump or climb stairs. You can learn more about recognizing those day-to-day changes in mild hip dysplasia: what it changes day to day and signs of hip dysplasia in adult dogs.

Severe Hip Dysplasia

Severe is the most significant grade. The femoral head may be largely outside the acetabulum, and extensive bone remodeling, flattening, and arthritic change are common. Muscle mass around the hip often deteriorates over time. Dogs with severe grades may walk with a pronounced sway, bunny-hop at the trot, or struggle significantly to rise. But here’s the thing owners are often surprised by: some dogs with severe grades have adapted remarkably well, while some with mild grades are clearly uncomfortable. The grade is structural — not a direct measure of pain.

How Does the Grade Influence Treatment?

Treatment decisions aren’t made by grade alone — your vet will weigh the grade alongside your dog’s age, body weight, activity level, and clinical signs. That said, the grade gives an important framework.

Mild grade dogs are usually managed conservatively, at least initially. Weight management, joint supplements, controlled low-impact exercise, and anti-inflammatory medications are the typical starting point. Many mild-grade dogs do well for years without surgery. Hip dysplasia management strategies covers the full range of conservative options.

Moderate grade dogs often need a more proactive approach. NSAIDs (non-steroidal anti-inflammatory drugs) are commonly prescribed, physical therapy and hydrotherapy are strongly recommended, and surgical options become a more active conversation — especially in younger dogs whose joints haven’t yet developed significant arthritis.

Severe grade dogs frequently benefit from surgical evaluation, particularly if they’re young and otherwise healthy. The three main surgical options are Triple Pelvic Osteotomy (TPO, best in young dogs before significant arthritis), Femoral Head and Neck Ostectomy (FHO), and Total Hip Replacement (THR). You can read through the tradeoffs in hip dysplasia surgery options: TPO, FHO and THR compared.

Does the Grade Change Over Time?

Yes — and this is important. Hip dysplasia is a progressive condition. A dog graded mild at age two may shift to moderate by age six or seven, as the secondary arthritis that develops in response to joint instability continues to advance. This is one reason why weight management is not optional — every extra pound increases the mechanical stress on joints that are already compromised.

The OFA issues preliminary grades for dogs as young as four months old, but the official registry evaluation requires the dog to be at least 24 months old. Preliminary grades are useful for early warning, but they can change. Many breeders and owners are surprised to find a puppy’s preliminary borderline grade resolve to fair at the official two-year evaluation — or the reverse.

Is the Grade the Same as a Prognosis?

No. The grade tells you what the joint looks like structurally right now. It doesn’t predict exactly how much pain your dog will be in, how quickly the condition will progress, or how well they’ll respond to treatment. From what I’ve seen talking to other hip dysplasia caregivers, the dogs who do best long-term are the ones whose owners took an active role early — staying on top of weight, getting into a good exercise routine, and working with a vet or rehab therapist rather than waiting until the dog was in crisis.

If you’re still sorting out whether hip symptoms are coming from the hips or something else entirely, hips or spine? telling rear-end problems apart is worth a read before your next vet appointment.

Related Reading

• Hip X-Rays for Dogs: What the Vet Looks For
• Hip Dysplasia Management: Meds, Supplements & Lifestyle
• Signs of Hip Dysplasia in Adult Dogs

Frequently Asked Questions

What do the hip dysplasia grades actually mean?

Hip dysplasia grades — excellent, good, fair, borderline, mild, moderate, and severe — describe how well the hip joint fits together on X-ray. The OFA assigns these grades after evaluating the degree of joint laxity, bone remodeling, and arthritis present. Grades of excellent through fair are considered normal; borderline through severe indicate increasing degrees of dysplasia.

Can a dog with a severe hip dysplasia grade live a good life?

Many dogs with severe hip dysplasia do live comfortable, happy lives with the right combination of pain management, weight control, low-impact exercise, and sometimes surgery. The grade describes the joint structure, not your dog’s quality of life — that depends heavily on how the condition is managed. Working closely with your vet or a rehab specialist makes a significant difference.

Does a mild hip dysplasia grade mean my dog won’t need treatment?

Not necessarily. Some dogs with mild grades show noticeable pain and stiffness, while others with more severe grades seem relatively comfortable. The grade is one important piece of information, but clinical signs — how your dog moves, where they hurt, and how they respond to activity — guide treatment decisions just as much as the X-ray findings.

At what age is a dog graded for hip dysplasia by the OFA?

The OFA issues preliminary grades for dogs as young as four months old, but official, registry-eligible evaluations require the dog to be at least 24 months old. Evaluations done before two years of age are considered preliminary and may change as the dog matures.

Hip dysplasia grades are a tool, not a verdict. Whatever number came back on your dog’s X-ray, there’s real, actionable help available — and the fact that you’re researching this means you’re already ahead of the game.

This guide is based on real experience and should be used alongside professional veterinary care. Always consult your veterinarian before starting any new treatment or making changes to your dog’s care plan.