The Q-check KAFO/AFO

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By Micah Alford, MSPO

One difficult patient presentation many O&P practitioners have encountered is severe genu recurvatum of 15-30 degrees with a lateral rotational thrust or corkscrew moment. A heavy-duty, stainless-steel sidebar KAFO is often the only device option for a patient with this condition. However, these orthoses have poor patient compliance. Unfortunately, an individual may prefer to walk without such an orthosis until his or her knee joint deteriorates, which results in either the need for a total knee replacement or a lifetime using a wheelchair for mobility.

These patient challenges, combined with hemiparesis, also present a challenge for the orthotist: What is the best way to control the knee and ankle motion to reduce unwanted motion without adding substantial weight to the orthosis that would then make it too difficult to don and doff, especially for a patient who may have limited hand function or no use of one hand?

Figure 1

The Q-check orthosis is a good solution for this problem. This design combines the function of an AFO with the control of a Swedish knee cage.

The Q-check orthosis is based on an adjustable, three-point pressure system in the sagittal plane to adjust knee extension resistance. Patients with knee weakness will often compensate by going into full knee extension, locking the knee to prevent it from buckling. This repetition causes damage to ligamentous structures, eventually leading to recurvatum. The Q-check strap allows the practitioner to fine-tune that extension moment quickly and easily by adjusting a single Velcro® strap.

The AFO portion has an adjustable floating calf strap, the Q-check strap, built into the AFO to limit knee hyperextension. With this unique design, the clinician can easily adjust for the exact amount of extension the knee can experience during midstance without having to contour metal sidebars or add or subtract padding. Additionally, with this design there is no need for a conventional thigh section as on a KAFO, which reduces the weight of the device. The lighter weight makes it easier for the user to don and doff and advance the orthosis, often without assistance. A C-fold strap is used in place of the conventional thigh section to anchor the sidebars onto the thigh segment. A lateral T-strap or lateral plastic wedge can be added if needed to help control an equinovarus moment at the ankle.

Figure 2

The posterior floating calf strap can also be used with an AFO. This provides fine-tuning of knee extension and flexion, used with solid ankle or plantarflexion-stop plastic AFOs, without the addition of the weight and height of a KAFO, providing additional knee stability without crossing the knee joint. This variation on a theme is also easy to fabricate.

Fabrication

Cast Modification

Modify the AFO normally with a three-sixteenth inch thick buildup on the proximal-posterior calf (Figure 1 and 2).

Pull the plastic using dummies for easy slot fabrication (Figure 3).

Bend sidebars to 30-45 degrees of flexion just proximal to the knee center (Figure 4).

Figures 3 and 4

Q-check Strap Fabrication

Sew a one-inch C-fold strap to the posterior side of the LDPE with a D-ring on one side and the hook on the other, facing anterior. Attach two pieces of the hook to the anterior side of the LDPE. Sew neoprene material to the anterior section, rounding it over the edges (Figure 5 and 6). Rivet a two-inch in length loop to the posterior calf and fold over the LDPE (Figure 7 and 8). Feed the straps through the slots and secure it with Velcro (Figure 9 and 10). End here if you are only making an AFO.

Figures 5 and 6
Figures 7 and 8
Figures 9 and 10

Fabricate the covers for the metal uprights. Rivet the proximal strap around the anterior thigh and distal thigh strap posteriorly using one- and two-inch Dacron-backed Velcro. (Figure 11-13).

Finish the KAFO (Figure 14-16).

Figures 11 and 12
Figures 13 and 14
Figures 15 and 16

The Q-check KAFO/AFO was designed and created by John Quigley, CO, Hanger Clinic, Westchester, Illinois. Special thanks to Greg Karavites, COA, CTO, for his help throughout this process.

Micah Alford, MSPO, completed his orthotics residency with Hanger Clinic, Westchester, Illinois, where he is currently completing his prosthetics residency. He can be reached at or at 708.447.9860.