Removable Transfemoral Socket
|
I recently had the opportunity to spend some time with David Falk CPO and his staff in the Fort Lauderdale area. One of the most enjoyable aspects of my travels is the chance to see first hand how other clinicians solve patient problems, and this trip was no exception.
I saw several transfemoral amputees, generally geriatric individuals, who were readily able to don their prostheses from a seated position, even though they had roll-on sleeve suspension. Despite the usual arthritic fingers and less than stellar balance that are commonplace in this population, each of these folks could put on the prosthesis correctly and independently.
When I asked about this flexible socket variant, I learned from Jeffrey Price CPO that he had originated the idea to make donning simpler for elderly patients when he practiced in Philadelphia, and had found it equally useful when he moved to Florida and joined this practice. Over time, he has developed a very straightforward fabrication method that adds no additional weight, cost, or material thickness compared to any other flexible socket-rigid frame prosthesis.
As the following photos illustrate, the inner socket and roll-on sleeve suspension are one functional unit. The shuttle lock is thermoformed directly into the base of the flexible inner socket. This has several advantages. Because the shuttle alignment is then independent of the socket alignment, the lock can be placed on the mid-sagittal and mid-coronal axes of the residual limb. This makes it much easier for the pin to "hit the bulls-eye" on the first try, particularly when there is a hip flexion contracture - which is all too common among the elderly.
|
To make engaging the pin even easier, Jeff routinely makes a fenestration in the anterior distal socket near the shuttle lock. This "porthole" permits the patient see directly if the pin is centered over the lock, and such visual feedback helps them learn to don the roll-on sleeve correctly. If the pin doesn't engage perfectly on the first try, the patient inserts one finger through the porthole to guide the tip of the pin until it clicks right in place.
Once the pin is safely engaged one or two clicks, the amputee then stands carefully and body weight engages the lock fully. Well fitting proximal socket contours guide the residual limb into place and provide rotational control. Fastening a single lateral hook and loop closure that anchors the socket to the frame, and they are ready to ambulate.
|
Like every good idea, it is not suitable for all cases. Jeff does not recommend this method when the patient can don the liner effortlessly from a standing position, or when a direct suction socket is feasible. As a practical matter, he generally reserves this technique for functional level 1 & 2 patients and for selected level 3 individuals.
It is particularly valuable for bilateral cases, whether transtibial/transfemoral or bilateral transfemoral. It works well with fleshy residual limbs, and even better with tapered limbs. Many patients prefer to wear the socket all day and simply release the hook and loop strap to temporarily remove the rest of the prosthesis. If they have a secondary waterproof prosthesis [not uncommon in Florida and other coastal regions], they can use the same socket for both artificial limbs.
|
Fabrication of the inner socket is straightforward, with bubble-forming preferred to insure that the distal socket is thick enough to provide structural rigidity for mounting the shuttle lock. The proximal socket can be as thin and flexible as is desired. It is important to use a very strong D-ring [ideally a welded one] in the lateral suspensor, since this is all that holds the prosthesis and the socket together. This approach is probably contraindicated for high impact activities, but presumably amputees who are that active will prefer a direct suction socket or be able to don the sleeve from a standing position.
For additional information, feel free to contact Jeff at 561-495-5040.
