Proof of Concept and Evaluation of a Novel Implant Device for Plantar Plate Repair

Abstract

The plantar plate is a fibrocartilaginous tissue beneath the metatarsophalangeal joint (MTPJ). Plantar plate function centers around maintaining the static stability of the MTPJ, and its integrity facilitates the dynamic stabilizing functions of surrounding soft tissue structures. Injury to the plantar plate can cause significant forefoot discomfort focused around the MTPJ, swelling, and altered forefoot biomechanics from toe instability. Significant injury like either partial or complete tear of the plantar plate commonly requires surgical intervention to repair the tissue. As fibrocartilage, the plantar plate lacks an intrinsic capacity for robust healing, thus requiring a surgical repair aiming to restore proper function. Existing plantar plate repair techniques afford different perspectives for restoring plantar plate biomechanical function, though room for improvement exists for an enhanced repair. Our senior design team developed a novel approach for plantar plate repair using a two-piece snap fitting permanent implant. This novel technique was reduced to practice and required further experimental analysis of its functional capacity to inform future development. Two methodologies were used to evaluate the novel implant device designed for plantar plate repair. An implant isolated mechanical testing protocol was developed to evaluate the implant and suture construct of the repair in anatomically relevant orientations. A human cadaver tissue model protocol was employed to evaluate the integrity of the native plantar plate tissue, a simulated conventional repair, and our novel implant fixation repair. These methodologies used uniaxial tensile testing with custom test configurations to evaluate the structural integrity and properties of the implant-suture construct and simulated tissue only or tissue-repair constructs, respectively. Our results provided encouraging support for the use of mechanical testing and the continued development of this novel implant device for plantar plate repair. Additionally, qualitative outcomes from this testing revealed additional avenues to improve the novel implant device in support of further advancing the product for future use in the field of podiatric medicine.