The U.C.B.L. orthosis was developed in 1967 at the University of California Biomechanics Laboratory which is obviously where its common name. The primary forces used in attempt to “correct” a “flatfoot” were: 1. The deep, molded, heel cup holds the calcaneus in a correct (“correct or corrected or neutral” typically being vertical to the ground) position. 2. the medial contoured arch of the rigid UCBL is supposed to “support” or directly lift the long medial arch vertical at the midfoot and 3. The lateral wall intended to “control” the outside border of the foot.
Overall, a poor design showing a poor, albeit anecdotal understanding of the joints of the lower ankle and midtarsal joints and total disregard for human gait. In many cases the thermoplastic trim-lines extend to the end of the toes or at best proximally to the sulcus. In either case the unintended blocking and trapping of the lower leg forward rotation during late stance phase of walking results. Proximal, undesired compensations at the knee and hip result.
Further, there was no possible way the shape and depth of the thermoplastic heel cup could control the calcaneus enveloped within a large soft tissue envelope. Grab and squeeze the calcaneal fat pad tighter from side to side? It was not going to control the axial rotation and shifting of the lower limb above regardless; unless of course a bolt or screw was placed through the heel bone to “lock” it in place.
The lateral wall may be vertical, tall, and flattened while the plantar-lateral aspect of the UCBL remained without shape or contour. Most often the lateral-plantar portion of the UCBL did not represent the child’s foot, the corrected foot or for that matter did not appear to be representative of the osseoarticular arrangement and structure of a human child’s foot.