Post-Traumatic Hindfoot Arthritis.

The hindfoot is functionally defined as the articulations between the talus, calcaneus, navicular, and cuboid. It is a biomechanically important peritalar unit for shock absorption and propulsion with the subtalar and talonavicular joint essential to its function. The primary cause of hindfoot arthritis is post-traumatic. Other causes include long-term misalignment such as adult-acquired flatfoot, cavus foot, and inflammatory arthritis. Prevention of post-traumatic hindfoot arthritis is the primary objective. Anatomical reduction and fixation of articular hindfoot fractures is the preferred pathway. This article discusses the principles of treatment of hindfoot arthritis. When post-traumatic changes cannot be managed by nonsurgical means, an anatomical well-aligned arthrodesis is indicated. This article addresses the principles of managing this condition, which have been championed by Professor Sigvard T. Hansen. New approaches and techniques are discussed that achieve the goals of a stable, functional plantigrade foot.

Finite element model-based evaluation of tissue stress variations to fabricate corrective orthosis in feet with neutral subtalar joint.

BACKGROUND: The subtalar joint position during static stance is a crucial determinant of the peak plantar pressures and forms ideal reference point for any intervention in foot-related problems for leprosy-affected patients. OBJECTIVES: The study pursued the hypothesis through a three-dimensional model that stress will be minimal in the distal joints of the foot when the subtalar joint is in neutral static stance position. STUDY DESIGN: Finite element model. METHODS: The computed tomography images of the feet for five patients suffering from Hansen's disease having no muscle weakness and joint restriction were acquired. The gray intensities corresponding to the bones of the foot from the computed tomography images were three-dimensionally reconstructed. The three-dimensional model of the human foot, incorporating the realistic geometry, and the material properties of the hard tissues were then analyzed using a finite element solver for the stress distribution on bones of the foot. RESULTS: The results demonstrate that the position of the calcaneum in the static stance position does contribute to the varying stress in the foot. CONCLUSION: The stresses in the bones of the foot are minimal while the subtalar is in neutral position; this position will be suitable for foot orthotic fabrication. Clinical relevance The clinicians, therapists, and podiatrists having less engineering skills can quickly assess the patient and get optimal results on the stress associated with the joints of the foot.