The gait pattern in patients with severe myelopathy, specifically cervical myelopathy, is characterized by several distinct features. These features include hyperextension of the knee in the stance phase without plantar flexion of the ankle in the swing phase. Additionally, patients with cervical myelopathy experience significant reductions in walking speed and step length, prolonged stance phase duration, decreased single-stance phase duration, and increased variability in gait parameters.
One of the prominent aspects of the gait pattern in cervical myelopathy is the hyperextension of the knee during the stance phase. This means that the knee joint is excessively straightened, resulting in a backward position of the leg during walking. This hyperextension is often compensatory in nature, as patients with cervical myelopathy may have weakness or impaired control of the muscles responsible for knee flexion. As a result, they rely on knee hyperextension to maintain stability and prevent buckling of the knee joint.
Another characteristic feature is the absence of ankle plantar flexion during the swing phase of the gait cycle. Normally, during swing phase, the ankle joint undergoes plantar flexion, which allows for clearance of the foot and prepares it for the subsequent heel strike. However, in patients with cervical myelopathy, the impaired coordination and weakness of the ankle muscles lead to a lack of ankle plantar flexion. This can result in a dragging or shuffling of the feet during walking, affecting the overall efficiency and smoothness of the gait pattern.
Patients with cervical myelopathy also exhibit reduced walking speed and step length. The combination of knee hyperextension and lack of ankle plantar flexion contributes to a slower and more cautious gait. The reduced step length can be attributed to the decreased range of motion at the knee and ankle joints, as well as the overall weakness and impaired muscle coordination in the lower extremities. These factors collectively limit the ability of patients to take long strides and cover significant distances while walking.
Furthermore, the stance phase duration is prolonged in patients with severe myelopathy. This means that the duration of time spent with the foot in contact with the ground is increased compared to individuals without myelopathy. The prolonged stance phase is likely a compensatory mechanism to maintain stability and balance during walking, as patients with myelopathy often experience weakness and impaired proprioception. This prolonged stance phase allows for better weight-bearing and stability, albeit at the cost of reduced efficiency and speed.
Conversely, the duration of the single-stance phase is decreased in patients with cervical myelopathy. The single-stance phase refers to the period of time when only one foot is in contact with the ground during walking. In normal gait, this phase allows for propulsion and forward progression. However, in patients with myelopathy, the decreased single-stance phase duration indicates a reduced ability to generate adequate push-off force and propel the body forward. This further contributes to the slower walking speed and reduced step length observed in these patients.
In addition to these gait abnormalities, patients with cervical myelopathy may also exhibit increased variability in their gait parameters. This variability can manifest as inconsistent step lengths, uneven weight distribution, or irregular timing of gait events. The increased variability is likely a consequence of the underlying spinal cord dysfunction, which affects the coordination and control of the muscles involved in walking.
The gait pattern in patients with severe cervical myelopathy is characterized by distinct features including knee hyperextension, lack of ankle plantar flexion, reduced walking speed and step length, prolonged stance phase duration, decreased single-stance phase duration, and increased variability in gait parameters. These abnormalities are a result of the underlying spinal cord dysfunction and can significantly impact the mobility and functional abilities of individuals with cervical myelopathy.