Orthosis as Medical Device in case of Peripheral Arterial Disease (PAD)
General Information on PAD
What is PAD?
In Germany, around 4.5 million people (as of 2023) suffer from peripheral arterial disease (PAD), also known as intermittent claudication, which increases in frequency with age. This chronic circulatory disorder usually occurs in the lower extremities and is a secondary disease of arteriosclerosis in about 95% of cases. The disease cannot be cured, but its progression can be delayed.
How does PAD Manifest Itself?
PAD usually progresses gradually, depending on how quickly and severely the vessels become constricted and the blood flow is restricted. The type and severity of PAD is categorised into 4 stages using the Fontaine classification.
Stage I: The patient is considered asymptomatic. Initial symptoms, such as cold feet or skin changes, pale skin or poorly healing wounds, are not recognised as signs, so the diagnosis is usually made by chance.
Stage II: Those affected become aware of PAD. Due to the lack of oxygen supply, the muscles underneath the constriction hurt cramp-like during exertion, for example when walking. A temporary limp (intermittent claudication) may occur. The pain subsides again at rest. In addition, functional gait restrictions can occur due to weakness of the foot lifter and calf muscles. Depending on the painless walking distance (>/< 200 m), this stage is divided into a and b.
Stage III: The blood circulation is so severely impaired that the typical pain also occurs at rest, when lying down and at night.
Stage IV: In the most severe stage of PAD, the tissue is severely damaged. Poorly healing ulcers develop and life-threatening infections can occur. In the case of complete occlusion, the tissue dies completely, resulting in a necrosis.
Due to the increasing, painful strain, those affected move less and consequently suffer from weakened muscles. The symptoms usually start in the feet in the form of muscle atrophy. Paralyses of the foot and lower leg muscles can also occur. In stage II, the typical weakness of the calf muscles (plantar flexors) and the foot lifting muscles (dorsiflexors) often leads to functional restrictions in gait, such as a drop foot, and causes great instability when standing and walking as the disease progresses. A lack of pressure relief also promotes the development of chronic wounds and often leads to Partial Foot Amputations.
How Can PAD Be Treated?
While a full recovery is impossible, therapies can help to improve circulation, alleviate symptoms and slow the course of the disease, prolonging life and improving quality of life for those affected.
As arteriosclerosis is the main cause of PAD, an unfavourable lifestyle significantly contributes to its development. Risk factors such as a lack of exercise, smoking and an unhealthy diet should therefore be avoided. Preexisting conditions such as high blood pressure and diabetes should be controlled with medication. Depending on the degree of severity, medication, e.g. blood-thinning or vasoactive agents, or surgery, e.g. the widening of narrowed vessels with catheters and the insertion of stents, or even amputations can be used. In the updated S3 guideline of the German Society for Angiology (DGA), which will be published in 2024, minimally invasive procedures and amputations will become less common. Instead, a conservative therapy with medication and exercise in the form of structured gait training is recommended as part of the standard treatment.
Why an Orthosis with NEURO SWING System Ankle Joint Helps
Previous Options and Typical Errors in the Orthotic Treatment for Patients with PAD
Unfortunately, the production of a custom-made foot orthotic without a custom-made orthosis is still considered the gold standard for patients with PAD. The disadvantage of such treatments is that although pressure peaks are reduced, the overall pressure exerted on the foot by the body weight is not. The pressure is merely redistributed and thus inevitably increases to other areas of the foot. However, a sufficient reduction of the overall pressure or pressure relief of the entire foot is necessary to reduce the risk of a partial foot amputation and to ensure long-term aspects such as the patient's mobility and quality of life.
Many patients with PAD develop a weakness of the foot lifting muscles as the disease progresses, which is usually treated with a simple dorsiflexion assist orthosis. The resulting weakness of the calf muscles is typical, but often goes unrecognised. Dorsiflexion assist orthoses compensate for the weakness of the dorsiflexors, but they have no effect on the weakness of the plantar flexors, which cause a deactivation of the forefoot lever. Insecurities when standing and walking are insufficiently treated with a simple dorsiflexion assist orthosis. Therefore, a thorough physical examination and a modern approach to orthotic treatment options are important.
Modern Orthotic Treatment Options for Patients with PAD
In order to strengthen the affected muscle groups, ensure the ability to walk and improve balance when standing and walking, orthoses with the appropriate orthotic functions should be used for patients with stage II at the latest. A custom-made orthosis with a front shell and rigid foot piece, the dynamics of which are realised via a system ankle joint with precompressed spring units, transfers part of the overall pressure exerted on the foot via the orthosis directly into the ground. This results in a reduction in the pressure exerted on the foot. The rigid foot piece also allows the already reduced pressure to be distributed even further over the entire foot area. The treatment is completed by a custom-made foot orthotic which can be integrated into the foot piece.
In addition to redistributing and reducing pressure, a dynamic orthotic treatment counteracts muscle fatigue in the foot lifting and calf muscles.It is of great advantage to use a system joint from the NEURO SWING range for the production of an orthosis, as the precompressed spring units mounted in the system joint not only compensate for the impaired dorsiflexion assist, but also activate the forefoot lever. The spring units are strong enough to counteract the body weight. This helps to bring the body into a stable balance and restore the supportive area. This allows for upright, straight and therefore safe standing. The gait significantly improves and the orthosis ensures lower energy consumption when walking. This becomes visible when the heel is lifted during heel-to-toe movement. The required resistance in both directions of movement (dorsiflexion and plantar flexion) can be adjusted to the individual muscle weakness of both muscle groups separately using the exchangeable precompressed spring units.
You can find an overview of the different system joints at knee and ankle height here. The most important functions of each system joint are explained in the corresponding product description.
You can get to know patients who have already been treated with an orthosis in our User Stories and Patient Videos.