Recent advancements in above knee technology have had a major focus on microprocessor designs. These designs have many unique features and functions that make them exciting to work with as a prosthetist. These knees can allow the right patient to aggressively pursue daily living activities while still providing functionality, safety, and stability. These microprocessor designs are yet another tool in a prosthetist’s arsenal.
To truly realize the benefit of these microprocessor knee units however, a patient must first and foremost be fitted and provided with a comfortable socket. If a patient cannot tolerate wearing a limb, the benefits of any knee unit are lost. A strong yet flexible socket designed to each patient’s specific needs is fundamental to the success of any above knee amputee. This need is even more profound when a heavy microprocessor knee unit is added to the limb. The problems raised by an ill fitting socket design are only compounded when additional weight is added.
In my personal experience, socket comfort is achieved in three major areas: (1) the casting process; (2) the modification of the cast; and (3) the fabrication of the socket. The key step in the casting process is taking a hand cast of the patients residual limb. By taking an accurate hand cast, we are able to most accurately capture the patient’s size and shape. In the modification process, we relieve pressure intolerant areas, maximizing patient comfort and fit. Finally, with the use of thermoplastics, we fabricate a strong, lightweight, yet flexible socket. Thermoplastics provide us with the unique ability to minimize weight, maximize strength, while at the same time uniquely maintaining flexibility. This flexibility helps distract negative impact and pains commonly associated with more rigid socket designs.