Fiberglass casts led to soft-tissue injuries in 63% of cases – hallmark research confirms what many veterinarians already knew

Meeson et al. (2011) provided quantifiable proof that casts cause many complications. In this text, Dr. Saku (MD, PhD) comments on the key findings of this influential study and discusses why an alternative to fiberglass casts is necessary – and how a wood-based, heat-mouldable alternative he is currently researching may fit the bill.

The study titled “Soft-tissue injuries associated with cast application for distal limb orthopaedic conditions: A retrospective study of sixty dogs and cats” found that soft-tissue complications are very common and can occur at any time during the casting period1.  

The study looked at 60 animals that were treated with a polyurethane fiberglass. In most of the cases, the cast was applied after surgery. The most common cast associated soft-tissue injuries (CASTI) found were:

• Pressure sores (43 %)

• Rubs or erythema as sole injury (10 %)

• Erythema associated with other injuries (7 %)

• Swelling concurrent with other lesions (7 %)

“It proves in black and white that cast treatment does not work as it should: over half of patients get complications. A safer way to cast would mean less need for surgery, and this would help decrease complications”, Dr. Saku says.  

Less complications would lead to faster healing times, less follow-up visits, and lower treatment costs for pet owners. Dr. Saku believes the study by Meeson et al. gives indications on how this could be achieved.  

Cast application requires substantial skill, even if it is something many veterinary professionals do almost daily.

Incorrect cast application is a common culprit to complications

Casts are part of the everyday of veterinary professionals, and it is easy to forget the substantial skill their application requires. The authors of the Meeson 2011 study note a difficulty with replicating the original fit of the first cast when changing the cast.

It is no surprise then, that incorrect cast application is one of the three main causes behind complications found in the study – the other two being incorrect case selection and postoperative management2.

“The risk of complications is higher with more re-applications, because the more casts you apply, the more opportunities there are to mess up”, Dr. Saku comments.  

He is currently researching a possible solution to the issue: A ready-made but mouldable splint that lends itself to precise adjustments with little effort as swelling goes down.

“With UPETS you can use the same cast – so you will already have the general shape of the patient’s leg moulded into it, and you can easily adjust using a heat gun if needed. This should help prevent complications and makes follow-up visits faster”, Dr. Saku explains.

Plastic waste is an issue many in the healthcare industry are trying to solve. Biodegradable materials are a key to finding more sustainable solutions.

A non-toxic alternative to fiberglass is safer for both the patients and planet

Fiberglass and other synthetic materials seem to have excellent mechanical properties and are fast and clean to apply. On the other hand, they are harder to mould as precisely as plaster of Paris, for example. These materials also often have sharp edges, which can attribute to skin damage.

Some of the synthetic materials are also toxic. Fiberglass casts, for example, contain toxic isocyanates and require protective gear when applied and removed. Isocyanates have been linked to, amongst others, asthma in humans. For pets, they can pose potential risk if the animal tries to chew on their cast, for example.

“Human patients rarely chew on their casts, but dogs and other animals might. This is one of the reasons I’m excited about the new wood-based and non-toxic alternative. UPETS is totally safe for animal patients. It’s safe even for humans to eat the Woodcast material, although it doesn’t taste very good", Dr. Saku says. The re-usable material also helps cut down material waste,

“If you have a fiberglass cast that you remove with a saw, that cast is not reusable – you must make another one. With UPETS, you just remove and re-apply it and adjust it if necessary. Once the patient is healed, you can dispose of the splint with bio waste as it’s fully biodegradable”, Dr. Saku says.

Casts can hinder early detection of complications

In the Meeson study, owners were often the first ones to notice complications. However, early signs like swelling and odour are easy to miss as animals can hide symptoms. Traditional external coaptation methods, like fiberglass, do not support early detection at home.

“It can happen that after two weeks of having the cast the owner takes the pet for a check-up appointment, and a serious issue is detected”, Dr. Saku describes.

Wounds that are caught early require less invasive treatment. But the Meeson research shows that in most cases the complications had time to develop unnoticed, and often required surgical debridement and intravenous antibiotics, for example3. This is costly for the pet owner and requires time and resources from the clinic.

Circumferential casting is one of the oldest, most rigid immobilization methods. However, it is also the most prone to complications.4 Fiberglass as a casting material was first introduced to use in the 1970’s. An update to both method and material seems long overdue.

Luckily, such an update is underway – read about the science and research behind UPETS


[1] Meeson, R.L, Davidson, C., Arthurs G. I., 2011, “Soft-tissue injuries associated with cast application for distal limb orthopaedic conditions: A retrospective study of sixty dogs and cats”

[2] Meeson, 2011.

[3] Meeson, 2011

[4] Saku, S., 2022, ”Splints and braces – A Literature Review”. Internal document, available upon request.