Custom Walker with Rotational Hip Support

Designers: Clark O’Niell, Graeme Waitzkin
Client Coordinators: Eliza Bankert
Supervising Professor: Dr. Larry N. Bohs

Our client was a six year old girl with athetoid cerebral palsy who used a walker for ambulation. She had outgrown her walker, and no commercial walkers fit her specialized needs. The goal of our project was to provide a custom walker that the client could use for both gait training and quotidian ambulation.  We developed a custom walker with a rotational hip support, sling seat, and armrests that could accommodate her narrow shoulders.  The walker facilitates increased mobility and independence.

How this project helped
The custom walker has been well accepted by the client.  The large tires allow her to traverse terrains that she was unable to navigate before, thus enabling her to attend activities such as her brother’s soccer games.  The rotational hip support, suggested by her therapist, appears to improve her gait while walking. The client’s mother commented, “[She] has never had a walker that suits her like this one.  I took her to Target recently and she took off in her walker, all by herself, and went over to the toys section with her brother.  Do you know what it means to go where you want to instead of where your mother chooses to push you in your chair?”

Figure 1 shows the custom walker. The walker is based on an adapted commercial frame, Busy Bee (Ottobock), which has been tested for safety and reliability.  Custom armrests, a sling seat, and rotational hip support are added to a steel top bar that attaches to the commercial frame. The armrests are adjusted to a relatively narrow lateral position to accommodate the client’s torso. The hip support is mounted on the rear of the top bar.  For structural testing, the total dead load was assumed to be 60 lbs, the estimated maximum weight of the client. Modeling indicated that at this load the steel would not yield and the deformations would be infinitesimally small.

The hip support, which is constructed from the hip belt of a backpacking frame pack, opens in the front and is closed with a plastic clip.  A heat-molded polyethylene panel inside the belt provides rigidity and flexibility. The belt attaches to a slotted back plate (see Figure 2) to allow vertical adjustment.  The rear end of the back plate has a threaded coupling that attaches to a boat rail antenna mount, which provides simple rotational adjustment using a single knob.  The antenna mount can be adjusted horizontally on the top bar to re-center the client after the hip rotation angle is changed.  The walker also has an easily removable sling seat, which is shown in front of the client in Figure 3.

Custom armrests are constructed from bicycle handgrips, metal, foam, molded polyethylene and neoprene because the armrests on the original frame were too large.  The couplings that attach the arm support to the frame clamp to the top bar, so they can be adjusted in angular and fore-aft position.

The cost of parts for the custom walker was $335, not including the Busy Bee frame.

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