Plastics In Lower-Limb Orthotics
Warren A. Carlow, Jr., C.O. *
Manuel J. Almeida, O. *
This article is not designed to introduce any new orthotic devices into the field, but rather to show variations of some previously described orthoses and to demonstrate the unlimited possibilities of plastics in orthotics.
It is our intent to encourage orthotists to consider application for plastics to a greater range of patients, and to exchange ideas and techniques with the hope that more such devices will be prescribed by physicians and clinic teams throughout the country.
Details of fabrication will not be covered since each orthotics facility has its own equipment and techniques.
In fabricating thermoplastic orthoses the orthotist must first evaluate each patient very carefully and plan exactly what is to be done. He can then proceed to measure and cast the patient, modify the cast accordingly, and fabricate an orthosis with a minimum of error, and expense. It is recommended that each orthosis be trimmed as little as possible until the initial fitting, when it is cut down just enough to facilitate donning. The shoe is fitted, the patient walks, and further trimming and adjustments are made to fit each individual patient's requirements.
Follow-up is the most important part in the orthotic management of these patients. Depending on the patient, we usually follow
them from three weeks to six months. Some are followed for years as their needs change as they grow older or their condition changes. During this period more alterations are made, such as straps, SACH heel and other shoe modifications, more trimming, padding, etc. to correct and/or support a deformity and eliminate any unnecessary gait deviations. The accompanying photographs show just a few variations of knee-ankle-foot orthoses, ankle-foot orthoses, and plastic insert orthoses.
Valgus of the ankle has always been a problem to control. By using an AFO with a valgus correction strap (Fig. 1 ) in older patients, especially C.V.A., this system provides a very comfortable and effective means of control. The strap is 2-in.-wide Velcro attached to the inside medial wall at or above the malleolus and extending to the outside lateral wall around the posterior aspect of the orthosis. For static control the medial wall is trimmed more anteriorly and is padded. This system of rigid ankle AFO's and KAFO's is used quite frequently in our area for younger patients with Multiple Sclerosis, Muscular Dystrophy, Cerebral Palsy, and Spina Bifida.
There are so many versions of AFO's that it would take a book to show them all. Again we would like to emphasize individualization of each orthosis, and the need for an extensive evaluation of each patient to determine the characteristics of the orthosis that will best meet his needs.
Fig. 2 shows a 23-year-old veteran who had a spinal-cord injury L2 and L3 and who also suffered the loss of the great toe bilaterally. Attempts with conventional bracing were unsuccessful and the devices were discarded by the patient. He was fitted with bilateral AFO's with a rigid ankle which supported his ankles and knees quite well. A full steel shank was applied to the shoes to eliminate toe break which caused irritation to his toes and amputation sites. This patient walks with one forearm crutch and is completely self sufficient.
Fig. 3 A and B show a similar case, but with a different diagnosis. This Muscular Dystrophy patient's needs were just the opposite of those of the patient shown in Fig. 2. Rather than a knee flexion problem he had
hyperextension of the knee and a very spastic dropfoot. He was also fitted with bilateral AFO's with a rigid ankle. Neither patient could stand or walk for any length of time. The MD patient was content to use a wheelchair most of the time because it took too much effort to walk. He now uses Canadian crutches and ambulates quite well. This method of rigid ankle AFO's in these type of cases are in reality KAFO's because they are supporting the knee as well as the ankle foot complex.
Fig. 4 A-C show KAFO's with hinged anterior section. This type of orthosis is used when anterior and posterior control are needed as in a Multiple Sclerosis or Muscular Dystrophy patient. Note high posterior wall and rigid ankle. The angle of the foot and heel height are very critical as these patients are very unstable and can only control about a 5 deg. zone before the knee buckles either forward or back.
Fig. 5 shows a young Spina Bifida patient wearing bilateral KAFO's with semirigid ankles. The medial wall is trimmed more anteriorly to support a valgus condition of the ankles while the lateral wall is trimmed more anteriorly to support a valgus condition of the ankles while the lateral wall is trimmed more posteriorly to let the ankle correct itself. These types of orthoses are also used on Cerebral Palsy and Muscular Dystrophy patients and patients with various below-knee deformities. This particular patient had bilateral knee flexion contractures also.
Fig. 6 shows a polypropylene Patella-Tendon-Bearing AFO for use in below-knee fractures or severe foot or ankle deformities or burns where little or no weight can be put on the foot. When using this orthosis with fractures we recommend starting with a rigid ankle and grinding away material to provide more flexibility as the healing takes place. By hinging the anterior section we can leave the posterior aspect more proximal to the knee, thus providing more support and elimination of the need for any straps, as in Fig. 7.
Fig. 8 shows just one of the many different types of orthoses for the patient who requires an above-knee orthosis. This particular device combines the AFO concept with a quadrilateral socket, below-knee prosthetic knee joints, and an elastic knee extension assist.
Fig. 9 shows a conventional above-knee orthosis, with a quadrilateral socket, that we use when a locked knee is required for ambulation, as in above-knee fractures.
Fig. 10 represents five years of orthotic treatment of a unilateral postpolio patient. He was first seen with a conventional "long leg brace." He is an exceptional patient, and was determined to walk with as normal an appearance as possible. Because his affected side was the right, he wanted ankle motion so he could drive an automobile, and he was provided with an above-knee laminated orthosis with a 90 deg. anterior stop at the ankle and a 180 deg. stop at the knee using below-knee prosthetic side joints and the AFO concept (Fig. 10, left). He wore this for approximately two years, after which it was decided he could do without the proximal portion of the orthosis. A below-knee orthosis was made of similar design which he wore for another two years (Fig. 11 ). He still wanted something better and a polypropylene AFO with SACH heel was made (Fig. 10 , center). We decided to use an anterior hinged high back AFO (Fig. 10 , right), because he didn't like the slapping at the knee of his previous orthosis and could not tolerate a posterior strap. The patient walks very well with this orthosis, but we are still working on an orthosis which combines the advantages of the rigid ankle and the movable ankle KAFO.
The KAFO and AFO concept is a very effective means of treating patients with leg-length discrepancies, especially those as a result of polio.
Fig. 12 shows a 10-year-old boy with a congenital absence of the femur that resulted in a 10 1/2 in. leg-length discrepancy. This orthosis can be considered a HAFO since the proximal anterior portion contains the hip, which is dislocated. Fig. 12 shows the orthosis ready for fitting anterior and lateral views with a foam filler, alignment jig, ankle block, and prosthetic foot. A dynamic walking alignment was achieved with the initial fitting (Fig. 12 ) and the orthosis was completed in the same manner as a conventional below-knee prosthesis. This is the second orthosis of this type for this patient. His first one lasted more than two years before he outgrew it. The only thing he cannot seem to do is ride a bicycle. We will try to overcome this problem with a knee unit in his next orthosis since his right heel should be level with the left knee at that time.
Summary
We have found that as thermoplastics have become more popular in orthotics, especially since the introduction of polypropylene, we have been able to use plastics in an estimated 65 percent of our patients who would normally require a "long leg" or an "above-knee double upright brace." About 80 percent of these patients have been converted to a below-knee plastic orthosis. It is our hope that some new orthotic devices will be developed as a result of this and future articles of this nature. Also it is hoped that orthotists will be encouraged to customize each orthosis to meet each patient's particular needs, rather than provide them with a "standard" model.
|
