INITIAL PATIENT POSITION
Using the tap-step pattern (“up with the good,” also known as the step-to-step pattern), the patient climbs two or three steps then turns around to prepare for descent training. With the primary therapist guarding from below and assisting practitioner positioned above/behind, the patient steps forward into the initial position. The initial position places the midfoot of the prosthetic foot at the step's leading edge (Figure 5). This minimizes the risk of toe loading, which is necessary to trigger the prosthetic knee's swing phase release. This foot placement permits the prosthetic knee's stance control to manage knee stability, minimizing the risk of knee collapse during step descent.
Once initially positioned, the primary therapist provides a visual cue (hand target) for the patient to contact with the toes (or limb end point)12 of the sound limb (Figure 6). The hand target must be positioned far enough in front of the patient to permit the sound side heel to adequately clear the step. Similarly, the hand target must be in the correct vertical position, such that the toe can contact it without the patient having to flex a joint to reach it comfortably. Contacting the sound-side toe to the therapist's hand target is important to establish kinesthetic memory of all joints12,13 relative to the body's orientation when performing stair-descent. In addition, reaching out the sound foot to touch the hand target while standing on the prosthetic limb at the step's edge promotes increased weightbearing in the socket and balance on the prosthetic side in preparation for descent. It should be noted that this position is considered precarious by many patients and may require multiple repetitions or multiple practice sessions to accomplish because of the need for coaching, practice, and reassurance. When the patient is confidently able to step out and reach the hand target with precision, they are ready to proceed to step descent practice.
STEPPING DOWN LEADING WITH SOUND LIMB
Using the instructions above in “Initial Practice,” the patient places his sound foot out in preparation for stepping (or step descent practice). Once the sound foot contacts the hand target, the therapist lightly grips the lateral aspects of the sound forefoot and shows the patient visually that the heel need only descend approximately 6 to 8 inches (15.2–20.3 cm). The therapist informs the patient that to place the sound heel on the lower step, the prosthetic knee must be slowly flexed. Allow the patient to return the sound foot to the step while the therapist explains that the patient is quite likely contracting the hip extensors of the residual limb to maintain prosthetic knee extension as he stands on the stairs at rest. In other words, the patient is pulling his residual limb into hip extension against the posterior wall of the prosthetic socket. The therapist can tap on the anterior socket wall and explain that either 1) force must be applied to the anterior socket wall or 2) the force being applied on the posterior socket wall must be decreased to flex the prosthetic knee for stair descent.
With this explanation completed, provide the hand target once again, for the sound side foot. Once the foot contacts the target, instruct the patient to push on the anterior socket wall (or release force on the posterior wall) to step down. Once this has been accomplished successfully and if repetition is desired, have the patient reset his sound foot on the step and repeat as necessary until mastered.
STEPPING DOWN LEADING WITH PROSTHETIC LIMB
Once the patient is able to descend leading with the sound limb and the sound limb is bearing the patient's weight, the next component is to descend leading with the prosthetic limb. This is the most common stair descent technique for patients and fits with the very typical “down with the bad” instruction. Although not likely needed, the same hand target practice can be used for this portion as well.
RECIPROCAL, STEP-OVER-STEP DESCENT—PUTTING IT ALL TOGETHER
At this point, the patient has mastered descent with both limbs individually and is ready to practice the reciprocating, step-over-step pattern descent. Start the patient three to five steps up from the floor in the initial position. The first time the patient attempts this whole skill pattern, it is recommended that the two therapist method of guarding be utilized. With the guarding and safety considerations in place, begin with the hand target for the sound side, so the patient descends leading with the sound limb first. Once the patient steps down leading with the sound limb, he should immediately be instructed to step down over the step the sound limb is on with the prosthetic limb and repeat this reciprocal, step-over-step pattern. Practice and cue as necessary.
Once reciprocal stair descent is mastered on a smaller therapy set of stairs, other factors should be considered and introduced given each patient's unique functional needs. A metronome14 can be utilized, for example, to alter or solidify the stepping rate. Depending on the patient's stability needs, guarding can potentially be progressively decreased from two to one therapist and eventually to decreasing levels of assistance. The staircases practiced on should be altered to introduce variance in terms of step size, environmental distraction, hand railing availability, lighting, and climate conditions.
The purpose of this technical note is to introduce a technique to train stance yielding prosthetic knee users how to walk reciprocally down stairs. As a part of a clinical trial, utilizing this technique, we trained 19 transfemoral amputees to descend stairs reciprocally. We measured their stair descent ability and confirmed that after training, all were able to demonstrate reciprocal stair descent.2 We also indicated that this may not be appropriate for everyone to practice on a daily basis as a part of their routine ambulatory activities.
The knee moment reported (normalized to height and weight: N/kg) for reciprocal stair descent in transfemoral amputees using stance yielding knees is higher than that reported for stumble recovery, sitting down from standing, and knee flexion in the loading response of gait.1,15 – 17 (Table 1) We suggest that it is important to consider training all transfemoral amputees using stance yielding knees in reciprocal stair descent as it potentially has functional carry over and motor learning in other functional activities. Other such activities that rely on stance control include stumble recovery, sitting down from standing, and knee flexion in the loading response of gait. In addition, these tasks are included in the initial set up and adjustment of a C-Leg.18,19 For instance, at the initial C-Leg fitting and setup, one of the first tasks is to have a patient sit in a chair repeatedly until patient and prosthetist are satisfied with sitting resistance. The user should be satisfied and confident with the resistance, such that they are willing and able to apply as much load into the prosthesis as possible, thereby unloading the uninvolved side and maximizing kinetic symmetry while transitioning from stand to sit.16
With emphases on patient outcomes becoming the norm and the functional capabilities of prosthetic componentry expanding, the role of physical rehabilitation to assure mastery of device function is increasing. The presence of detailed rehabilitation techniques in the literature is limited. This technical note presents a strategy for training the transfemoral amputee how to utilize the reciprocal stair descent capability of stance yielding knees and offers considerations to expand for individualized functional needs. The technique is associated with positive clinical outcomes data, but the task of reciprocal stair descent is probably not appropriate for all transfemoral amputees utilizing stance yielding prosthetic knee mechanisms. Whether or not a patient ever utilizes the technique in daily life, training such patients with a comparable technique, at least therapeutically, may have functional significance in other daily activities such as stumble recovery during a missed step, in moving from stand to sit, and during the loading response of gait.
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Keywords:© 2012 American Academy of Orthotists & Prosthetists
C-Leg; Mauch SNS; microprocessor knee; physical therapy; reciprocal gait; rehabilitation; transfemoral amputee