Abstract
Purpose: Plantar pressure sores can lead to metatarsalgia depending on the patient’s activity level and age and on the status of the muscle-tendon system and the morphology of the forefoot. In 1995, Tanaka and Maestro attempted to quantify the relative lengths of the metatarsals. The purpose of this work was to check the results reported by Maestro and to try to define a morphotype classification of the metatarsals.
Material and methods: We analysed two series of normal feet: no apparent deformation, no callosity, no pain, no history of trauma or surgery. Fifty “normal” feet were selected among the personnel of the orthopaedics unit. Mean age of the 25 subjects was 30.3 ± 9.6 years, 44% were women. This series was compared with 34 “normal” feet reported by Maestro (age 55.2 ± 17.2 years, 62% women) used to define criteria for geometric progression (1995). A standing dorso-plantar radiograph was obtained with the same protocol for all patients. All radiographs were digitalized with a Vidar VXR-12 plus, then analysed by two observers with the semi-automatic FootLog measurements. The following measurements were recorded: SM4-M4 (distance between the line passing through the centre of the lateral sesmoid and perpendicular to the foot axis and the centre of the M4 head), M1 = d1 – d2 (length of the M1/SM4 head – length of the M2/SM4 head), Maestro criteria 1 = d2 – d3, Maestro 2 = d3 – d4, and Maestro 3 = d4 – d5.
Results: An SM4 line passing through the mid third of the M4 head (+2mm proximally / centre M4 head / −4 mm distally) as normal. The notion of row 2 geometric progression was conserved by tolerating 20% variation (Maestro 1 ± 1 mm, Maestro 2 ± 1mm, Maestro 3 ± 2 mm). Feet were classed in four metatarsal morphology types with subgroups: normal feet (line SM4 passing through the mid third of the M4 head – geometric progression) – long M23 (SM4 line centred on the mid third of M4 – but alteration of the geometric progression) with four subgroups (long M2, long M3, long M2-3, long M23 long 2) – M4M5 hypoplasia (distal SM4 line / at mid third of M4) with four subgroups (by geometric progression: long M2, long M23, long M23 long M2) – others (long M1: M1 > 3.3 mm causing distalization of SM4).
Discussion, conclusion: FootLog enables rapid radiographic measurements with excellent precision and intraobserver (variations from 0.1 to 0.2 mm and 0.1 to 0.5°) and interobserver (variations from 0.1 to 0.5 mm and 0.1 to 1°) reproducibility. In the two series of clinically “normal” feet, the measured parameters were strictly comparable. Radiologically, 31% were “normal”, and the others (30% long M23 – 37% M4M5 hypoplasia – 2% others) could be considered as predisposed to potential forefoot disorders. Finally only 48% of the subjects had the same morphotype for both feet. This study adds further precision to earlier qualitative evaluations of the forefoot architecture.
The abstracts were prepared by Pr. Jean-Pierre Courpied (General Secretary). Correspondence should be addressed to him at SOFCOT, 56 rue Boissonade, 75014 Paris, France
