New Type of Fixation Allows Regular Limb Hygiene and Stay in Water

Introduction

Fixation systems have evolved since the beginnings of human civilization. The first mentions of primitive wooden splints come from ancient Egypt. A major revolution was the discovery of so-called Paris plaster in the 18th century, which is a direct predecessor of current plaster fixations.

The fixation systems available so far share several negative aspects, such as the impossibility of daily limb hygiene, skin irritation under the fixation with the risk of developing dermatitis, or unpleasant sensations like foul-smelling limbs and skin itching. In this regard, another breakthrough occurred only in 2017, when a unique fixation system was developed for medical purposes.

Basic Properties of the Fixation

The fixation system is supplied in the form of two-dimensional templates with a mesh structure. The fixation consists of 3 different parts with distinct properties: the core, the cover, and the pad. The core of the fixation is made of thermoplastic with the addition of carbon fibers, which shows high strength under normal conditions but softens at temperatures exceeding 80 °C. The cover, on the other hand, is made of a soft elastomer from polycaprolactone, and the pad intended for contact with the skin is made of soft polyolefin foam, which is otherwise used, for example, in the production of functional clothing. Both the cover and the pad exhibit a high melting point and maintain the structure of the fixation when the core softens.

The fixation system is heated during application in a special oven to a temperature at which the core softens, allowing the fixation to be shaped to the limb. The core cools down relatively quickly, reaching the required strength to immobilize the limb within a few minutes.

The main advantages of the fixation include its very low weight, the ability to perform daily limb hygiene, and even stay in water. The unique structure of the fixation ensures sufficient breathability, allowing daily skin care and reducing the risk of skin irritation, skin atrophy, or post-fixation hypertrichosis.

During therapy, due to the possibility of regular hygiene, a lower incidence of skin pruritus and unpleasant odor is observed. A positive psychological aspect is the possibility of continuous visual contact with the limb and greater comfort during removal, which is done simply by cutting the plastic clips with scissors.

Study Findings

The effectiveness and safety of the fixation system have currently been verified by a limited number of clinical studies. Min et al. published a study comparing the new type of fixation with polyurethane resin fixation. The analysis included 22 patients with ankle sprains who underwent therapy with both types of fixation during the healing process. The study focused only on subjective treatment parameters such as function, adverse effects, or quality of life. Significant improvements in most subjective parameters were observed with the new type of fixation, especially in terms of unpleasant sensations and the ability to perform regular limb hygiene during treatment.

Sang focused in his study on comparing the efficiency and safety of the fixation in the treatment of upper limb fractures in pediatric patients compared to conventional synthetic fixation. A total of 69 patients were included in the final analysis, with fractures healing without complications in both groups. Mixed results were observed in questionnaire systems, with some parameters favoring the new type of fixation. An interesting finding was the recording of several cases of hypersensitivity reaction to the new type of fixation, which resolved spontaneously by padding.

Future Development

Currently, templates are available for fixing injuries and non-traumatic diseases of the upper limb from the elbow area distally. In the near future, templates for ankle fixation will also be available. There are also efforts to improve the material to be stronger, with a lower risk of mechanical complications. In the longer term, there should be templates developed in the form of a corset, neck collar, or plaster spike intended for the treatment of developmental hip dysplasia.

Conclusion

Based on current experiences, it seems that the new fixation system could represent a real revolution in the conservative treatment of injuries and non-traumatic diseases of the musculoskeletal system. Mainly because it is the first to be fully compatible with the water environment, allowing regular hygiene, but also stay in water. Although synthetic fixations also allow for water stay, they are not suitable for regular hygiene due to the nature of circular fixation and padding with wettable materials.

The main disadvantages of the new fixation apparatus include lower mechanical resistance compared to conventional types of fixation, but also the economic burden for the patient, as it is not currently covered by public health insurance.

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Sources:
1. Szostakowski B., Smitham P., Khan W. S. Plaster of Paris-short history of casting and injured limb immobilization. Open Orthop J 2017; 11: 291–296, doi: 10.2174/1874325001711010291.
2. Min B. C., Yoon J. S., Chung C.Y. et al. Patients' perspectives on the conventional synthetic cast vs a newly developed open cast for ankle sprains. World J Orthop 2020; 11 (11): 492–498, doi: 10.5312/wjo.v11.i11.492.
3. Sang S. N. Comparison of the equivalence between OPENCAST^® and conventional polyester cast in pediatric upper extremity fractures. School of Medicine (의과대학) Keimyung University 2020. Available at: http://kumel.medlib.dsmc.or.kr/bitstream/2015.oak/43387/2/THESIS-2020-017.pdf
4. OPENCAST is a next generation, shower-friendly cast. Available at: www.openm.com