rotation may also help maintain hip abduction. If this is not adequate to limit adduction, a medial knee support or block is often used (Figure 41). It should be noted that some providers and caregivers have used medial knee blocks inappropriately in an attempt to keep the pelvis back in the seating system. However, the purpose of this seating component is to keep the hips in slight abduction to keep the head of the femur in contact with the acetabulum, maintain pelvic alignment, and provide a stable seated position. The medial knee block is to limit excessive adduction only. Note in Figure 41 that the medial knee block is past the edge of the seating surface, as this block is placed medial to the knees or preferably at the distal thighs to avoid pressure on the medial condyles. Placing a knee block more proximally in an attempt to keep the client back creates pressure against the groin. Instead, strategies to limit forward migration of the pelvis should be used, as discussed previously in the section on posterior pelvic tilt. It is important to address excessive hip adduction, as this could lead to further range-of-motion losses and affect ADL such as dressing, toileting, and hygiene. Limiting excessive hip adduction often reduces overall extension as well as hip internal rotation. Figure 41: Medial Knee Support
The goals are to achieve anatomical alignment, if possible, and to prevent pressure of the lateral lower leg against the footrest hangers as well as to maintain ankle alignment by preventing ankle varus and forefoot supination (keeping the feet positioned flat on the footplates). These pads should ideally be placed on the distal thighs proximal to the lateral condyles to prevent pressure injuries and nerve damage. Windswept posture A windswept posture results when one leg is adducted and often internally rotated and the other leg is abducted and often externally rotated (Figure 43), giving the legs the appearance of being “swept” to one side. Figure 43: Windswept Posture to the Left
This posture is caused by range limitations, pelvic rotation, and sleep positions. Many clients sleep on their backs yet lack full extension of the hips and/or knees. As a result, the legs tend to fall to one side, leading to loss of range and this particular posture. Interventions are those used to address hip adduction and abduction. For example, if the client is windswept to his or her right, a medial knee support may be required at the left leg and a lateral knee support at the right. It may be possible to move the legs into alignment; however, this may pull the pelvis into rotation. Ensure that the pelvis is neutral and then correct the windswept posture as much as possible while maintaining a neutral pelvis (Sparacio, 2018). Goals of the intervention are the same as those for pelvic rotation. In addition, 24- hour positioning should be discussed and nighttime posture corrected. Knee flexion The client may position his or her knees in a flexed position, even past 90°; this posture is almost always due to tight hamstrings. The hamstrings cross two joints: the hips and the knees. To relieve the pull on the hamstrings, open the seat- to-back angle and/or decrease the knee angle. The challenge with decreasing the knee angle (particularly in adults, who have longer legs than children) is caster interference. The footplate will hit the front casters and interfere with turning the wheelchair if the footrest hanger is at 90° on most wheelchair frames. Using footrest hangers at 60° may not be possible for someone with tight hamstrings, however. Various hanger angles are available, and the footplates themselves can be moved rearward to flex the knee farther. Specialty footrest hangers are available to accommodate significant limitations (Figure 44). Many power wheelchairs offer a center-mount footrest hanger to minimize caster interference. Front- and mid-wheel drive power wheelchairs allow 90° footrest hangers without interference. Some ultralightweight rigid manual wheelchairs incorporate a 90° footrest that fits within the front casters, eliminating interference.
Note . From Stealth Products, n.d., retrieved from http://www. StealthProducts.com. © Stealth Products. Reprinted with permission. Hip abduction Hip abduction results in the knees moving away from midline and may be caused by range-of-motion losses, low tone, or even surgeries. Hip abduction is common in people with Duchenne muscular dystrophy (Kinali, Main, Mercuri, & Muntoni 2007). Many off-the-shelf cushions include a generic contour to prevent excessive hip abduction. If this is not adequate, lateral thigh or knee supports are used (Figure 42). Figure 42: Lateral Knee Support
Note . From Stealth Products, n.d., retrieved from http://www. StealthProducts.com. © Stealth Products. Reprinted with permission.
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Book Code: PTNC1023
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