For various reasons, from time to time, we encounter transtibial amputations with limited knee range of motion. If there are soft tissue limitations, then stretching and manipulation under anesthesia may help. These attempts may not gain back a functional ROM, especially if the contracture is capsular. In these cases, surgical revision may be the best option. However, the patient may choose not to undergo another amputation and we are confronted with designing a standard transtibial prosthesis as best we can to accommodate the flexion angle and compensate for the lack of knee flexion if the knee is immobile. This results in compensatory gait patterns such as vaulting, hip hiking, circumduction, etc.
I’ve found that a springy foot helps with forward progression and that using a pin locking liner at least allows the person to take his or her leg out of the socket and rest it on the top during sitting. However, the gait pattern still looks inefficient and unsymmetrical. Has anyone found a good alternative design for this problem, perhaps including external joints and thigh lacer? Are orthotic stance control knee joints strong enough and/or necessary with this design? What about mounting a hip joint to the back of the socket?
Thanks to all who reply,
Zach Harvey, CPO
