SLR - April 2022 - Lant Abernathy
Reference: Malakoutikhah, H, Madenci, E, Latt, LD. The Contribution of the Ligaments in Progressive Collapsing Foot Deformity: A Comprehensive Computational Study. J Orthop Res. 2022; 1- 13. doi:10.1002/jor.25244Level of Evidence: 3
Scientific Literature Review
Reviewed By: Lant Abernathy, DPM
Residency Program: Inova Fairfax Medical Campus – Falls Church, VA
Podiatric Relevance: Progressive collapsing foot deformity (PCFD), once known as adult acquired flat foot deformity is a multi-planar, developing abnormality of the foot and ankle that can lead to gait abnormality, pain with ambulation, and a decrease in quality of life. Multiple studies have examined what soft tissue anatomic structures can progress this abnormality in vivo, ex vivo, and in imaging. Finite element analysis (FEA) is a computational program and simulation that can analyze any parameter. Using this technology, the purpose of this article was to analyze each contribution of the ligaments of the foot for the sequential progression and predication of PCFD in computer models.
Methods: Using a CT of a neutrally aligned cadaveric specimen, the composition and material property of different tissues of the foot were composed to create a PCDF and normal foot. These were then put through biomechanically simulated conditions for a stance phase of gait. To simulate elongation of the ligaments, they were either pre stretched based on previous references, or removed in total. Each ligament evaluated was sequentially removed, and measurement of reported angles to determine planal deformity. Measurements of progressive strain were calculated to quantify the amount of attenuation it would take in each ligament to produce a PCFD as well as restoration of the normal foot.
Results: It was found that removal of an isolated ligament in the foot shown no acute deformity. Loss of plantar fascia, superficial deltoid, and spring ligaments in combination with any of the plantar ligaments demonstrated collapse in sagittal, frontal, and transverse plane respectively. The ability of any individual ligament to restore foot alignment was found in sagittal plane with the plantar fascia, coronally with the deltoid, and transversely with the spring ligament. The highest progressive strain outcome of these ligaments was the spring ligament, while the lowest was that of the plantar fascia, long plantar ligament, and short plantar ligament.
Conclusions: In summary, seclusion of failure of one ligament did not lead to deformity, and that various combinations of failure of ligaments shown severe deformity. Although, this article is limited in that it is a computational software program, it does demonstrate information about the perplexing progression of PCFD. According to this model, multiple ligaments are responsible for failure of normal foot structure. This may add treatment ideas in addressing the soft tissue component of PCDF in combination with the bony architecture. Therefore, as experts in the area of PCFD, it is important to understand the etiology of the soft tissue attenuation for surgical planning as well as conservative care.