Cath Lab Digest

Preserving Motion: Understanding A Key Benefit Of The CBWO
One of the less touted but more obvious advantages to this basilar osteotomy is that it allows for continued natural ROM throughout the rest of the joints in the foot. Tensegrity is a system based on the naturally occurring, self-generating truss. It is an optimized, low-energy omnidirectional hierarchical construct. There is a cabling effect, an example of which is demonstrated by the cable cranes one would see in high-rise building construction projects. Changing one part affects the rest. Forces tend to return to their original state.
With biotensegrity, the foot becomes part of an integrated truss system. As in all truss constructs, there are only tension and compression elements. There are no levers or bending moments nor is there any torque at the joints.³³ This makes for a mechanically efficient system that stores and returns energy with smooth motion in an efficient gait pattern. Muscles develop tension on the fascia, providing protection, energy return and smooth motion.
Arthrodesis leads to “disintegration of gait” with increased energy consumption, decreased gait speed and increased pressure on other joints. One would see a good example of this with ankle arthrodesis.³⁴ Although fusion of the first metatarsal cuneiform joint will not have as dramatic effect as fusion of the ankle joint, is there any doubt that there will be some gait disintegration and new stresses placed on other joints?
Arthrodesing procedures create circumstances that are consistent with the aging process. Decreasing tension with loss of flexibility and mobility increases stiffness. There is decreased energy efficiency and increased demands on other joints.³⁵ Recently, Lakin, et. al., reported the quantitative significance of contact mechanics across the Lisfranc complex.³⁶ They eloquently demonstrated how each metatarsal cuneiform joint is significantly involved in regulating pressures and redirecting forces in response to leg bone axial compressive loads.
Dananberg has lectured extensively on the relationship of back-connected pathology related to decreased motion of the first metatarsophalangeal motion, and decreased motion of the first ray.³⁷ First ray plantarflexion is necessary for normal gliding motion of the first metatarsophalangeal joint. Mobility of the first ray allows increase range of motion of the first metatarsophalangeal joint.³⁸ Therefore, one should exercise caution when contemplating use of the Lapidus procedure.

Final Notes
Both the oblique CBWO and the Lapidus procedures are effective in correcting large IM angles. Both are moderately difficult to perform. Lapidus is the procedure of choice when there is metatarsocuneiform joint arthritis, painful motion or dislocation. The closing base wedge osteotomy is preferred in other instances because there is less shortening of the first metatarsal, better healing and less postoperative disability.
However, the most important advantage of the CBWO is preservation of motion across the first ray. One should be cautious in regard to the Lapidus procedure. It’s important to remember that arthrodesing procedures create circumstances consistent with the aging process and stiffness. Some gait disintegration and abnormal mechanotransduction to surrounding joints can lead to new joint pathologies and inefficiency in gait.

Dr. Green is the Director of Podiatric Surgical Residency at the Scripps Mercy Medical Center in San Diego. He is a Clinical Professor at the California School of Podiatric Medicine at Samuel Merritt College and is a Fellow of the American College of Foot and Ankle Surgeons. Dr. Green is also on the faculty of the Podiatry Institute and has a private practice in San Diego.

Dr. Kim is a recent graduate of the Temple University School of Podiatric Medicine and is a first-year PSR-36 resident at the Scripps Mercy Medical Center in San Diego.

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