Vanessa: It is great to be here for part two. I hope everyone else is having a good morning as well.
American Society of Hand Therapists (ASHT) Definitions
These definitions came from ASHT. We want to differentiate between splint and orthosis. I myself am still learning, so you might catch me saying splint when I really mean orthosis. When we say orthosis, that is the singular noun for probably what we often referred to as splint before. The plural form would be orthoses. They are designated into three different categories by ASHT.
First we have pre-fabricated. An example of pre-fabricated would be something that you take out of a box and give to a patient, maybe like a wrist cock-up for carpal tunnel syndrome. Custom fitted would be a neoprene thumb spica that has a thermoplast stay inside. There is a small feature that is part of the orthosis that can be custom fitted to the patient's thumb, so it is partly custom. Thirdly we have custom fabricated. Those will be the ones that we are going over this morning, a hand-based thumb spica and an ulnar gutter intrinsic plus.
According to ASHT, a splint refers to casting used for fractures or dislocations. An orthosis in contrast is either rigid or semi-rigid and supports weak or deformed body parts or restricts motion. ASHT recommends that we do not use the word splint when referring to orthoses. They specifically say the term splinting should not be used by therapists who are fabricating or issuing orthoses. Splinting is used by physician offices applying a cast. An example would be in Figure 1.
Figure 1. Example of a splint.
Yes, this is me wearing a splint after an enchondroma repair in 2013.
Orthosis Location
When you receive a referral from a physician for an orthosis, it is very important that the locations are designated.
- Digit based
- Hand based
- Forearm based
- Long arm
- Radial
- Ulnar
- Volar
- Dorsal
There are a lot of different options as noted above.
An example of a digit-based orthosis might be used for trigger finger orthosis or perhaps a mallet finger, when you are just splinting the distal end of the digit. A hand-based example is a thumb spica that I am going to cover today. You can have a hand-based or a forearm-based thumb spica, and that does make a big difference. Some physicians prefer to have the entire forearm included. The one that we are going to do today is forearm-based, that would include the digits, the wrist, and then the rest of the forearm. Some physicians prefer only to splint the hand. It would just be the affected digit and then the rest of the hand, but it would stop at the wrist. A long arm orthosis would include the whole bicep, the elbow, the forearm, and the wrist, so that is a really long orthosis. It depends on what the diagnosis is, but again you will want to double-check with the physician when you get a referral.
Thumb Spica
Radial versus ulnar are other concepts to consider. Today we are doing the ulnar side of the hand. This example would be for a boxer's fracture. A radial type might be used for De Quervain's tenosynovitis, where you would include just the thumb portion and then the radial side of the forearm. Sometimes depending on the surgery, they might specifically request volar versus dorsal as well.
Poll #1
Who has made a custom fabricated, hand-based thumb spica before?
The majority say they have not.
Poll #2
For those of you that have made the custom thumb spica, what did you find the most difficult about this particular orthosis?
Answers include: wrapping around the thumb, clearing the web space for a comfortable fit, avoiding pressure areas for ADLs, the splinting material itself, and then clearing the MP joint. That gives me good information.
Common Indications
For the thumb spica, we are restricting the CMC joint and also the MP, but typically the wrist and the IP joint are mobile or relatively mobile. Common indications would be osteoarthritis or perhaps a UCL injury (Radomski 2008). Sillem et al from 2011 looked at the difference between using a prefab and a custom molded CMC orthosis (Figure 2).
Figure 2. Sillem et al. study.
A prefabricated orthosis usually comes from a box. You can also use a custom molded. A great example for this would be for CMC osteoarthritis. You can modify a neoprene thumb spica. It has a piece inside that is made of thermoplast. You put the whole thing in the splint pan, it heats up the thermoplast, and then you can mold it to the patient's thumb. This has an extra support that is molded to the patient's thumb. This is different than a custom fabricated where you have a piece of thermoplast, make a pattern, cut it out, and fabricate it.
In the Sillem et al. study, they are assessing the difference using the two types of orthoses on hand function, pain, and hand strength in adults with CMC osteoarthritis. They had 56 people in the group. They were randomly assigned for either the prefab or the custom molded orthoses. The treatment was a two-phase, four-week crossover trial. The hand function outcome measure that they used for this was the Australian Canadian Hand Osteoarthritis Hand Index. I am not personally familiar with that, but I will go over a different outcome measure in a few minutes that I prefer to use here in our clinic. In the end, they were looking at the differences between the two orthoses. They found that there was not a statistically significant difference for effect on hand function, grip, or pinch strength. Both orthoses demonstrated an improvement in hand function but there was not a big difference between the two. With the custom molded orthoses, people rated less pain, but they actually preferred the prefab neoprene version.
