My work on this topic began with translating Hoofing Marvellous’ open letter on tenotomy from English into German. That translation marked the starting point for a 50-page exchange with ChatGPT, during which I examined the plausibility of the claims, reviewed additional studies, and explored how “success” is defined in veterinary literature. The full original English letter – which includes all references to the studies cited – is attached below.
Let’s start with a very condensed summary of that letter:
Hoofing Marvellous calls for an end to the practice of cutting the deep digital flexor tendon (DDFT-tenotomy) in cases of P3 rotation. HM makes it clear that the underlying theory is biomechanically flawed and has been disproven in scientific studies. Several research papers show that a tenotomy neither reverses rotation nor realigns P3.
The letter highlights the lack of long-term studies and describes the continuation of tenotomy despite the absence of evidence as unethical. Instead, it calls for long-term, correct, functional hoof rehabilitation through skilled barefoot trimming, rather than invasive surgery.
I strongly recommend to read the attached full text!
After spending considerable time with the material, I can say without hesitation that I fully endorse this open letter.
For further perspectives on the topic I’d like to add a few thoughts, arguments, and observations of my own:
A tenotomy is an irreversible, non-healing, palliative measure
A horse that has undergone this surgery will never again move truly functionally. It becomes a pasture ornament, may still be used for breeding (which I consider unacceptable from an animal welfare standpoint), and its owners may be relieved it’s still alive. In reality, it is systemically and irreversibly suffering from Progressive Structural Breakdown – the progressive loss of structural integrity and vitality that prevents the musculoskeletal system from functioning efficiently.
Which brings us to how “success” is defined in the studies by Morrison and Eastman the letter refers to:
In their work, “success” simply means the horse is “pasture sound” – able to walk around more or less pain-free on a pasture for a while. According to Eastman, that’s why 73% of owners said they were “satisfied” with the outcome. In Morrison’s largest study (245 horses), only 13% were classed as “suitable for light work,” meaning walking or light leisure riding. Even that limited outcome (as well as the pasture ornament version) was only possible with specialised shoeing and other interventions.
From a biotensegral perspective:
The idea that cutting the tendon could derotate P3 within the hoof capsule is questionable even from a lever-based biomechanical view, because it ignores gravity and ground reaction forces – both of which oppose the DDFT. In a biotensegral movement system organised through adaptive tensile balance, severing the strongest tendon in the limb is equivalent to a structural breakdown. A horse’s health – including its musculoskeletal system, metabolism, respiration, and mental state – depends on movement. Always. Cutting that tendon sets in motion an irreversible Progressive Structural Breakdown, locking the horse into a state from which recovery is no longer possible.
A paradigm shift is needed:
Real change begins with a new understanding of movement. Yet veterinary schools – and the farriery schools often attached to them – still teach outdated models. This has to change. Even the best therapies are of limited use if there’s no shared understanding of how a healthy riding horse moves efficiently. The baseline data used to define “normal,” which underpin many footfall theories and other academic models, come either from unmanaged wild horses or from sport and leisure horses trained in pathological movement patterns.
Measures such as tenotomy, shortening the functional toe, moving the breakover point back, striving for higher heels, or continually reducing the weight-bearing surface all point to a fundamental lack of understanding about equine movement.
Given how slowly institutions change, and how structurally resistant they are to fundamental shifts, the best hope lies in more veterinarians, hoof care professionals from all backgrounds, and trainers embracing the necessary – and, for the horses, life-saving – paradigm shift.
An expanded call:
Finally, I’d like to build on Lindsay Setchell’s call by urging everyone who considers the measures above effective to re-examine the assumptions behind them, rather than repeating inherited dogma. The aim should be to enable genuine healing, not to design ever more elaborate crutches or amass more knowledge about making them.
Let us not settle for carrying on outdated methods simply out of habit. Every intervention, every trim, and every training choice has a systemic impact on the horse’s body – for better or for worse. A true paradigm shift means continually questioning what we know, integrating new insights, and consciously taking responsibility for the horse’s well-being. Those willing to look closely will understand: healing is not a matter of chance, but the result of understanding, patience, and consistent, deliberate action.
Open Letter from Hoofing Marvellous
