In my 15 years of clinical experience I have found that no matter how sophisticated the technology of a prosthetic device, if the socket doesn’t fit, the patient won’t wear it. Our practitioner’s guideline is to fit the socket to the patient, rather than the patient to the socket. If there isn’t proper union between the prosthesis and the human body, then the patient will not get the full advantage of the prosthesis, even if the componentry is technologically advanced. We advise amputees to visit their practitioner at least once every 6 months, and every 3 months for some, to see if they could benefit from an alignment recheck, inner socket remake or new supplies.
Once a good fit is established and the prosthesis is finalized, regular checkups with the patient’s prosthetic practitioner are encouraged. If the prosthesis doesn’t fit as well as it did when it was new, the patient will not get the benefit of the technology and will lose the efficiency of the device. A patient’s ill-fitting socket can be attributed to two main sources: a volume change in the patient, or overlong use of the prosthesis. Generally, when a prosthesis is built, the socket fits well and is aligned properly when the patient leave the facility. Over time, the body settles into the prosthesis, causing changes in the proportions of the socket. If there is any volume change at all, downsizing or upsizing more than 2 percent, it will cause the original fitting and alignment of the socket to no longer be sufficient. The fact is, if the inner diameter of the socket doesn’t always match the outer diameter of the leg in form, function, definition and size, then the residual limb will wiggle and the prosthesis will lose stability. The alignment will change by one or two degrees, and it will vastly change where the foot is in relationship to the floor. In turn, the patient will lose control of the prosthesis and will no longer get the full benefit of the technology.
Supplies are also a very important part of a good-fitting prosthesis. For a below-knee amputee, a liner is worn as the interface between the socket and the residual limb. When the liner wears out, it’s like driving a car on worn-out, wobbly tires. You might get where you want to go, but the “tires” won’t feel secure, and they will not keep the socket secure to the limb. With new liners, the patient will feel like the prosthesis fits better, even though there was no change in the prosthesis at all. Making sure there is a uniform layer of cushion between the patient and the prosthesis is a crucial element in keeping the prosthesis solid against the patient’s leg. Therefore, we recommend that liners be replaced every 6 months. The best way to get the full benefit of the technology in the prosthetic device is to be aware of any volumetric changes, to see a prosthetist at least every 3 to 6 months for an alignment and fitting checkup, and to keep supplies updated. This helps ensure that patients will get the maximum benefit from their prosthesis and its technology.
About the Author
Scott Sabolich, CP, LP, is owner and clinical director of Scott Sabolich Prosthetics and Research.