Is metatarsus primus elevatus truly observed in hallux rigidus? Radiographic study using mapping methods

• Published in: Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association 2019-03, Vol.24 (2), p.312-319
• Main Authors: Ohara, Kuniji, Tanaka, Yasuhito, Taniguchi, Akira, Kurokawa, Hiroaki, Kumai, Tsukasa, Yamada, Harumoto
• Format: Article
• Language: English
• ISSN: 0949-2658; 1436-2023
• DOI: 10.1016/j.jos.2018.09.005

Hallux rigidus and metatarsus primus elevatus (MPE) are associated, but their causal relationship remains unknown. Several surgical approaches for treating hallux rigidus are available. We evaluated morphological characteristics of hallux rigidus with different grades to determine the optimal surgical approach. The amount of degenerative change in the metatarsophalangeal joint on the preoperative roentgenograms was graded on a scale of 1–3. We analyzed the morphology of hallux rigidus using X-ray image mapping developed by our team. This study involved weight-bearing, dorsoplantar, and lateral foot X-rays of 36 feet from 26 patients underwent surgery for hallux rigidus (Group R) at our institution, and 26 normal feet (Group N). A two-dimensional coordinate system was used to analyze the sharps of these feet by converting each dot on the radiographs into X and Y coordinates. Diagrams of the feet from each group were drawn for comparison. Feet with grades 2 (Group R2) and 3 (Group R3) hallux rigidus and normal feet were compared by Kruskal–Wallis test. Mapping revealed that the tip of distal phalanges of the second, and third toes in Group R medially shifted (P