When designing a thermoplastic KAFO for a patient with severe genurecavatum, which modification could help control knee hyperextension?

To address knee hyperextension in a patient with severe genurecavatum using a thermoplastic Knee-Ankle-Foot Orthosis (KAFO), extending the distal posterior thigh more distally is an effective modification. This adjustment increases the overall length of the thigh section of the KAFO, which can enhance knee stability and provide better control over knee positioning.

When the posterior thigh section is lengthened, it allows for greater posterior support. As the individual moves, this modification can help prevent excessive extension of the knee, effectively managing the hyperextension associated with genurecavatum. The additional height of the orthosis provides more leverage and resistance to the forces that lead to knee hyperextension during weight-bearing and gait.

The other modifications, while they may contribute to the overall function of the KAFO, do not specifically target the prevention of hyperextension as effectively. For instance, decreasing the depth of the thigh portion or the calf section might not provide the necessary structural support needed to counteract the forces leading to hyperextension. Extending the proximal/posterior calf trimline could potentially restrict motion but does not directly address the knee's position in relation to hyperextension. Therefore, extending the distal aspect of the thigh section is the most appropriate modification to help