Objectification of indications for surgical restoration of the plantar plate in the treatment of multiplanar static foot deformities accompanied by hammertoe deformity of the lesser toes using ultrasound

Introduction Progressive multiplanar static deformity of the forefoot can result in hallux valgus, metatarsus primus varus, transverse flat foot and associated overload of the metatarsophalangeal joints (MTPJ) with plantar plate degeneration and rupture of MPT joints of the lesser toes leading to hammertoe deformity. Diagnostic ultrasound in the identification of plantar plate tears is easy to use at any medical center of the Russian Federation with orthopaedic services and provide a relatively inexpensive option compared with other advanced imaging modalities. The goal was to present ultrasound technology for accurate evaluation of the severity of plantar plate injury which may provide guidance for surgical treatment of hammertoe deformity of the lesser toes in patients with multiplanar static forefoot deformity. Material and methods The study recruited 88 participants with multiplanar static deformity of the forefoot, who underwent ultrasound evaluation according to the original method (RF Patent No. 2699383 "Method for determining the type of degenerative rupture of the plantar plate of the metatarsophalangeal joint due to overload metatarsalgia”) to objectify the results of a physical examination with the Hamilton-Thompson test performed for identifying the degree of instability of the MTPJ, and nonparametric analysis was produced with Pearson's Chi-square test. Results Evaluation of the severity of plantar plate injury in the study group of patients (n = 88) with the Hamilton-Thompson test and ultrasound imaging showed diagnostic error in 22.8 % of cases with the use of clinical methods that allowed reasonable reduction of surgical intervention in 2.3 % and substantial correction of the treatment approaches in 20.5 % preventing a complete plantar plate tear. Discussion The ultrasound scanning introduced in the algorithm for diagnosing the degree of plantar plate rupture facilitated an objective approach to the choice of the most appropriate treatment strategy for complicated multiplanar forefoot deformities accompanied by a non-rigid hammertoe deformity of lesser toes. Conclusion Preoperative ultrasound imaging of the plantar surface of the foot for detecting the severity of plantar plate injury should be included in the diagnostic algorithm for patients with complicated multiplanar forefoot deformities accompanied by a non-rigid hammertoe deformity of lesser toes.