Recognizing Early Lamellar Structural Failure in Performance Horses

Performance horses with body condition scores of 6 or higher are at increased risk of insulin dysregulation (ID) and metabolic-associated laminitis. When one of these horses presents with a subtle lameness or change in performance, however, we’re often quick to attribute it to joint or soft tissue pain. As a result, many equine athletes with subclinical laminitis or lamellar structural failure (LSF) go undiagnosed until the condition becomes more severe.  

During a presentation at the 2025 Equine Sports Medicine Symposium, Sammy L. Pittman, DVM, CF, founder of Innovative Equine Podiatry and Veterinary Services in Collinsville, Texas, described how veterinarians can identify early signs of metabolic-associated laminitis and take appropriate steps to intervene before it’s too late. 

Metabolic-Associated Laminitis 

Pittman describes acute laminitis as inflammation of the lamina that hasn’t yet progressed to structural failure. He said this form of laminitis is likely secondary to systemic inflammatory events, such as grain overload, dystocia, or colitis, that lead to lamellar bond damage and failure. An early radiographic sign might be a 1-2-millimeter increase in the lamellar zone without major coffin bone displacement. Lamellar structural failure secondary to metabolic issues, however, is often more insidious and obscure. The signs are subtle and might include: 

• Any combination of unilateral, bilateral, or quadrilateral lameness that might improve with abaxial sesamoid nerve blocks. 

• Stretched or widened white lines or bruising at the toe. 

• Lameness ranging from the typical founder stance with the hind feet camped under to mild unilateral lameness.  

• Positive hoof tester response. 

• Heat and digital pulse. 

• History of a systemic insult. 

Early recognition and appropriate medical and mechanical therapy are paramount to success, said Pittman. 

Once the lamellar structure itself starts to fail, he classifies it as chronic laminitis. “We’re past the inflammatory stage and now into the failure stage of the lamina.” 

Physiology and Biomechanics 

In Pittman’s experience, most metabolic cases already have radiographic bony displacement by the time they start showing signs of pain.  

“My thought on this is that hyperinsulinemia is causing low-level increased elasticity of the lamellar bond, and over time the laminae are getting more and more elastic,” he explained. “At some point they don’t necessarily have laminitis; they have more of a solar coriumitis because the lamellar bond isn’t efficient enough to support the structure of the foot. So now your coffin bone is sitting heavily in your solar corium. I think that’s where most of the pain is coming from in these types of cases.” 

Consider the two main components when dealing with loads in the horse’s foot: The suspension (e.g., deep digital flexor tendon, lamellar bond, hoof wall, collateral ligaments) and the support (frog, sole and digital cushion). The support components’ health is directly related to the suspension components. 

“Consider that if you were to lose lamellar attachment, that bone displaces and load is transferred into the solar corium, and that’s where your most significant pain originates,” Pittman reiterated. 

The Value of Venograms 

Digital venograms can help you more specifically diagnose the degree of damage to the lamina by identifying load-induced compression lesions and anatomical deviations that occur when lamina fail. This allows the practitioner to provide the most appropriate mechanical therapy relative to the identified lamellar failure.  

“It’s one of the most impactful diagnostics that I’ve been able to include in my practice since 2004 to understand and guide mechanical therapy,” said Pittman. 

Radiographic parameters he said he finds particularly important for laminitis cases include: 

• Coronary band to extensor process distance, which is very important as a serial measurement. 

• Horn-lamellar zone and lamellar zone separate to the horn zone. “You can measure all together, but really focusing on the lamellar zone will help you a lot in these early subclinical cases,” he said. 

• Sole depth is important to monitor with regard to health and recovery, throughout which you should see an increase in sole depth in well-managed cases. 

• Bone angle helps understand the innate biomechanics. 

• Palmar angle is going to tell you about mechanical changes with regard to DDFT tension. 

• Tendon surface angle. 

• Lucent lamellar circumflex juncture (LLCJ).  

You may or may not have significant radiographic changes—many of these cases don’t, said Pittman.  

Managing Metabolic-Associated Laminitis 

In the acute phase of laminitis, Pittman said his goal is to manage the inflammation, primarily through icing and anti-inflammatories. Once he identifies the degree of structural failure of the lamina, mechanical therapy is an important aspect for a successful outcome.  

“Early mechanical intervention has been the biggest factor in improving the outcomes of my laminitis cases,” he explained. “We need some form of mechanical shoeing to help shift the load away from the diseased lamina in order to give them proper blood supply and ability to heal,” he explained. 

These horses require mechanical support until the lamellar interface can function normally and withstand the load of the horse. 

Because obesity is the most common thread in all his cases, Pittman urges practitioners to help manage their patients’ weight by providing low-starch/low-sugar feeds and forages, ration balancers, and 1.2% body weight daily in forage if weight loss is needed. He also recommended hoof supplements to add biotin. 

Horses with insulin dysregulation might benefit from insulin-reducing medications such as compounded ertugliflozin or bexagliflozin. Test triglyceride levels before and during administration—especially in ponies and donkeys—he advised. 

Take-Home Message 

“Lamellar structural failure should always be on the rule-out list for these performance horses that look like every other coffin joint or navicular problem you’ve seen that day,” said Pittman. “You don’t want to get that call two weeks later from the owner saying, ‘Hey, my horse is coming out of the stall rocked back.’” 

He advised practitioners to test insulin levels before administering steroids to overweight horses and to pay attention to minor hoof growth abnormalities and terminal lamina irregularities. 

Related Reading

• What to Do if a Horse’s Foot MRI Has No Abnormalities
• Researchers Assess Prevalence of ID and Subclinical Laminitis in Sport Horses
• How Endocrine Disorders Impact Equine Athletes

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