More Study Needed to Compare Effectiveness of Different Splints for Acute Mallet Finger
Acute mallet finger is a condition where the finger joint closest to the finger tip cannot straighten out. This is caused by damage to the extensor tendon, the tendon that allows you to straighten that part of the finger. It is often referred to as a baseball finger or dropped finger. It is most often caused by something - often a ball - hitting the tip of the finger or thumb. The authors of this article discuss Doyle I mallet injuries, which may include the tendon coming away from the bone.

As early as 1930, surgeon M.L. Mason advocated immediate surgery to treat mallet fingers. However, because surgery is avoided whenever possible, the usual nonsurgical treatment for mallet finger is to use a splint. The type of splint used is controversial with each splint having its advantages and disadvantages. Some studies have shown the malleable aluminum splint to be effective, but it also may cause complications with the finger's soft tissue because of pressure. A volar (beneath the finger, palm side) padded aluminum splint, not customized for the patient, helps prevent pressure on the dorsal or top side of the finger, but it doesn't appear to control the correction of the deformity, as the padded dorsal aluminum splint does. As well, patients often don't like the splints because having their finger tip covered prevents them from touching things. The doctors who feel that the custom splint is superior feel that it works better because of the better fit on the finger. However, these dorsal splints also put pressure where the tendon rupture occurred, increasing the risk of complications.

There have been studies that looked at different types of splints (plaster of paris, Stack, wire, aluminum, and thermoplastic), but more research needs to be done in order to identify the best type of splint.

For the study, researchers recruited 87 patients with Doyle I mallet fingers. Seventy seven were available for follow-up at the end of the study. The patients were randomized to be treated with one of three splints:

1- Volar aluminum splint (30 patients)
2- Dorsal aluminum splint (29 patients)
3- Custom thermoplastic splint (28 patients)

Four patients dropped out of the dorsal group, two out of the volar group and four out of the custom group.

The splints were applied by an occupational therapist who taught the patients about the importance of the splinting. If the patients had any concerns or the splints needed readjusting, the patients could call the therapists for help. Treatment went on for six weeks, with the affected finger fully extended. After the six week period was over, if the angle of the bend was still more than 20 degrees or the patient was unhappy with the bend, another four weeks of splinting was done. This happened to nine patients. The patients were assessed at weeks 7, 12, and 24.

The doctors compared the x-rays from before treatment to those taken at follow-up. They also assessed the angle of the finger's bend, the results of the Michigan Hand Outcome Questionnaire, and any complications. Between the three groups, the researchers found there was no lag difference 12 weeks after splinting, but there was a slight superiority with the custom thermoplastic splint. The dorsal padded aluminum splint showed a difference of -16.2 degrees, the volar padded aluminum splint showed a -13.6 degrees and -9.0 degrees was seen with the thermoplastic splint. There were also no differences between the groups in the questionnaire or complications.

The authors note that their study had several limitations. For example, despite the randomization process, there were more smokers in the dorsal group than in the others. This may have influenced the outcomes. As well, the follow-up period was shortened so the researchers could decrease the chances of patients dropping out of the study. The researchers were also not able to determine how compliant the patients were with their splinting, nor did they determine if there were any other problems, such as difficulty with motion in the joint, stiffness, or deformity.

In conclusion, the authors wrote that further study is needed to determine any splint superiority.
Jeffrey Pike, MD, et al. Blinded, Prospective, Randomized Clinical trial Comparing Volar, Dorsal, and Custom Thermoplastic Splinting in Treatment of Acute Mallet Finger. In Journal of Hand Surgery. April 2010. Vol. 35. No. 4. Pp. 580-588.