Chronic venous insufficiency is a common and expensive problem in the United States and around the world. Although prevalence rates for varicose veins and chronic venous insufficiency are inconsistent when comparing studies, even the most conservatives estimates of 1% would equate to roughly three million people being affected in the United States.1 In certain cases, surgical interventions may be necessary to address the problem, but a conservative approach is often all that is required for the effective management of the disease process. Conservative management of active venous leg ulcers typically consists of pneumatic compression therapy, compression wraps and dressings to manage the wound environment. When the wound closes, interventions transition to compression garments and skin care to control the edema and skin changes associated with venous insufficiency. An important component that is often given a cursory mention, or left out altogether, is gait training. Teaching a proper gait pattern as well as exercises to strengthen the muscles of the lower extremities is particularly important in this population because people with venous ulcers have been shown to be at a higher risk for falls compared to similar groups without ulcers.2 In addition to reducing the risk of falling, a thorough gait assessment can identify impairments that contribute to the development of venous dysfunction. Once impairments are identified, a targeted gait training program and exercise prescription should be incorporated into the treatment plan for patients with disorders of the venous system in order to facilitate the calf muscle pump while walking. This article will review the normal gait cycle and briefly discuss interventions that can be useful in assisting the patient with venous dysfunction.
The normal adult gait pattern is a complex balance between mobility and stability that preserves momentum as body weight is shifted from one leg to the other thousands of times a day, usually without any adverse events. By utilizing a combination of active muscle contractions and passive tension in ligaments and joint capsules, people are able to maintain skeletal alignment that allows for progression within a narrow base of support without much concentration. When stability is challenged, whether it is due to weakness, limited joint range of motion, or unsteady surfaces, mobility is usually sacrificed to avoid a loss of balance. Common compensations that people make when stability is threatened are taking shorter steps, walking with a wider base of support and developing a shuffling gait pattern. As the degree of compensation required increases, the effort to maintain mobility increases as well which frequently results in less activity. For a patient with venous disease, a reduced activity level is particularly problematic as the calf muscle pump will not be activated to assist with venous return from the lower legs. To review how gait abnormalities will affect venous function, it is necessary to discuss the normal gait cycle. In order to evaluate what is happening during gait, the actions during an entire stride must be assessed. A stride, which is synonymous with a gait cycle, is the equivalent of two steps, one right and one left.
Due to the fact that it is the easiest point to see, the gait cycle usually starts when the foot first hits the ground and ends when the same foot hits the ground again. (Figure 1)
The gait cycle can be broken down into eight phases; five stance phases in which the foot is in contact with the ground, and three swing phases when the foot is not (fig 2-9 on following page). The first of these phases, called initial contact, is the point in time when the leading foot hits the ground. This is followed immediately by the loading response. During this phase of gait, the goal is to absorb the shock and transfer the weight of the body onto the foot. In normal gait, initial contact occurs with the hip flexed, the knee extended and the ankle at a 90° angle. This creates a contact point at the heel which serves as a fulcrum that the body then rolls over during the loading response. This causes the ankle to move from neutral to a position with the toes slightly pointed, which is referred to as plantarflexion. Because this activity is occurring with the foot in contact with the ground, this motion will affect the knee as well and will cause the knee to flex. An example of this coupling mechanism is seen when someone is standing in high heels or walking down a steep ramp which cause the ankles to plantarflex and the knees to bend in response. The controlled lowering of the ankle from neutral to a plantarflexed position so that the forefoot comes in contact with the ground is controlled by eccentric contractions of the extensor muscles on the anterior portion of the leg, primarily the anterior tibialis. If the extensor muscles of the ankle are weak, the forefoot falls to the floor uncontrolled and is referred to as a foot slap gait due to the sound the foot makes when it hits the ground. If the muscles are not strong enough to lift the foot or there is inadequate range of motion to achieve 90° for initial contact, the initial contact may occur with the entire foot flat on the ground, or at the forefoot. When this occurs, the ankle does not move through the same range of motion during the gait cycle, which can adversely affect the ability of the calf muscle pump to assist with venous return.
With the limb positioned in front of the body, as it is in initial contact and loading response, a flexion moment exists at the hip and the knee as well. If the gluteus maximus and other hip extensors are not contracting with enough force to counteract the flexion moment, the hips will jackknife into an excessive amount of flexion. Likewise, if the quadriceps do not contract to control the amount of knee flexion, the knee will buckle as the limb is loaded. In both instances, the force required to stabilize the joint increases as the step length increases. Weakness in any of these muscles will result in compensations to avoid putting the limb in a position of instability. Usually, this means taking a short step, or developing a shuffling gait pattern. From a venous standpoint, these compensations result in the same problem as were encountered at the ankle – a limitation of the effectiveness of the calf muscle pump.
The next task of the gait cycle involves moving the center of mass of the body from behind the foot, where it is at the end of loading response, to in front of the foot. This task can be broken in half into mid-stance and terminal stance phases. During mid-stance, the ankle dorsiflexes as the tibia moves forward on the ankle. The gastrocnemius and soleus muscles in the calf are active during this phase to control the progression of the tibia. At the same time, the quadriceps are firing concentrically to move the knee from slight flexion toward full extension. The activity of the quadriceps is assisted by momentum caused by the opposite leg swinging forward. Contraction of the quadriceps will continue until the ground reaction force shifts anterior to the knee joint, at which point, active muscle contraction is no longer needed to maintain stability of the knee. At the hip the gluteus maximus and hamstrings must work hard to prevent the hip from flexing. Activity of these muscle groups will continue until the ground reaction force is posterior to the hip joint axis. During terminal stance, the calf muscles continue to contract while they allow the ankle to move into its maximum degree of dorsiflexion without excessive collapse as the body weight moves over the forefoot. Muscles moving the limb in the sagittal plane at the hip and knee, specifically the gluteus maximus and quadriceps, remain relatively inactive as the position of the ground reaction force promotes stability at both joints. While the reference limb is in the mid-stance and terminal stance phases, the opposite limb is swinging forward, meaning the person is balancing on one foot. Balance problems due to hip abductor weakness, impaired proprioception, or any other factor will severely alter this phase. Once the cause of the balance deficiency is identified, it is important to address it since it will likely cause the person to place the swinging limb back on the ground sooner, resulting in a shorter step, and ultimately a shorter time that the calf muscle pump is working.
The final stance phase is called pre-swing, and takes place while the opposite foot is going through initial contact and loading response. Stability is restored in this phase as both feet are on the ground. As the body weight continues to shift anteriorly onto the opposite limb, the tibia moves forward which pulls the heel up off the ground as the forefoot remains stationary. This causes the ankle to move into plantarflexion and allows the knee to unlock and the hip to flex slightly. Although little muscle activity is needed in this phase, it is the point in the gait cycle where the ankle achieves the maximal range of plantarflexion. This is significant because both the maximal degree of dorsiflexion and plantarflexion occur when the limb is in a trailing posture during terminal stance and pre-swing, respectively. In other words, any limitation that is causing a patient to shorten her step length is adversely affecting the ankle motion necessary for the calf muscle pump to be effective and should be incorporated into the care of a patient with venous complications.
The remaining three phases are initial swing, mid-swing, and terminal swing. The purpose of these phases is to advance the limb while the body is supported by on the other leg and prepare the limb to accept weight for the next gait cycle. These phases comprise the part of the gait cycle from the time the toe leaves the ground at the end of pre-swing until the instant before the heel contacts the ground at initial contact to start the next cycle. Since the limb is not in contact with the ground, there is no calf muscle pump activity occurring, but impairments in this phase may result in poor positioning for weight acceptance to start the next cycle.
When the information gathered from a gait assessment is combined with other objective measures such as strength and range of motion, an individualized treatment plan can be developed. As mentioned previously, the ankle moves through its maximal range of motion while the stance limb is in a trailing posture, so a good starting point to assess is whether or not the person ever achieves this position in the gait cycle. If abnormalities are identified, then the cause should be investigated further. Physical therapists, who are experts in movement dysfunction, can be instrumental in identifying these problems and developing treatment plans to address deficiencies noted. Some of the common factors that lead to gait abnormalities are listed in Table 1, although this is not designed to be an all-inclusive list.
Although the exercise prescription needs to be tailored to the patient’s needs, certain recommendations can be applied to all patients with venous disease that do not have other conditions precluding exercise participation. First, exercises should be performed with compression garments or wraps in place. This helps to facilitate venous return by giving the calf muscle something to pump against. With compression in place, the patient should be fit with comfortable, wellfitting shoes that will allow for a heel to toe gait pattern. The simplest way to help a patient adopt this gait pattern is to have them practice taking the largest steps they can safely take. This tends to be much easier to understand than trying to focus on what each joint is doing during each phase of the gait cycle. As mentioned previously, mobility tends to be sacrificed in order to maintain stability, so the long term goal of ambulating with a heel to toe gait pattern often starts with ensuring the patient has the strength, range, and balance to maintain single limb stance. Whether the intervention needed involves balance activities, progressive resistance exercises to promote strength, or flexibility activities to increase range of motion will be dependent upon each patient’s condition. Regardless of the impairment, it is crucial that a person is using proper form while performing exercises and walking so poor habits are not reinforced. Along those same lines, if a patient has to adopt abnormal gait patterns to walk without an assistive device, then they are not ready to be transitioned off of that device. Once a proper heel to toe gait pattern is adopted, it is important that walking is performed enough to maximize its benefit. Although there are no recommendations specific to quantity of exercise for venous disease, it is recommended that a minimum of 30 minutes of moderate intensity aerobic exercise should be performed on most, if not all days of the week for overall health.