Axial rotation of the first metatarsal head in a normal population and hallux valgus patients.

HYPOTHESIS: Does metatarsal pronation exist and, if so, what is its impact? INTRODUCTION: Hallux valgus is a deformity associating angulation and a rotational component. The present study sought to investigate the nature and origin of the coronal plane displacement. MATERIALS AND METHODS: A prospective single-center radiological and anatomic study was conducted on 100 feet operated on for hallux valgus. Baseline X-ray determined the preoperative position of the 1st metatarsal head in the coronal plane. The range of motion (ROM) of the cuneometatarsal joint in pronation-supination was measured peroperatively. An anatomic study investigated possible diaphyseal torsion. RESULTS: Mean radiologic pronation in hallux valgus was 12.7° (range, 0°-40°). Cuneometatarsal rotational ROM was determined by adding peroperative ROM in pronation (mean, 9.3°; range, 0°-30°) and in supination (mean, 8.7°; range, 0°-20°). Intermetatarsal divergence showed no correlation with radiologic pronation or ROM in pronation. Radiologic pronation showed no correlation with peroperative ROM in pronation. Pronation of the metatarsal head was never observed without associated sesamoid pronation; the latter, however, was in some cases observed without the former. Twenty randomly selected metatarsal cadaver specimens from the anatomy laboratory of the University of Nice (France) showed diaphyseal torsion in 80% of cases, with the metatarsal head in neutral position or in supination with respect to the base. DISCUSSION: In hallux valgus, 1st ray pronation appears to be systematic, in contrast to the typical supination found in the general population. Metatarsal rotation is always associated with sesamoid rotation, whereas the converse is not the case: displacement of the sesamoids appears to displace the metatarsal head via the metatarsosesamoid ligaments. This "drive-belt" effect, however, varies in its mechanical properties and the transmission is imperfect and likely subject to progressive ligament stretching, so that head rotation does not exactly follow and may even become independent of the sesamoid displacement. Radiologic and clinical rotation thus do not match any longer. The anatomic study showed that, while diaphyseal torsion cannot be ruled out, the metatarsal pronation mainly derives from cuneometatarsal joint rotational instability, the evolution of which does not parallel lateral instability, no correlation being found between degree of varus and rotational instability. CONCLUSION: The present study found metatarsal pronation to be associated with hallux valgus, making a preoperative AP view useful; the underlying mechanism was generally cuneometatarsal instability. Although difficult to specify exactly without correlation between radiological and clinical data, any such pronation raises the question of whether replacing the metatarsal head on its sesamoid supports is sufficient to achieve stability in all planes, or whether on the contrary derotation should be associated to metatarsal valgization osteotomy to restore horizontal support. LEVEL OF EVIDENCE: Level IV.

[Chronic internal metacarpophalangeal sprains of the thumb. Anatomo-clinical classification and therapeutic consequences]. / Entorses invétérées métacarpo-phalangiennes internes du pouce. Classification anatomo-clinique et conséquences thérapeutiques.

In the light of a physiopathological study of severe medial strain of the metacarpophalangeal joint of the thumb in 20 cadaver hands, the authors propose a correlation between anatomical and clinical findings and a classification derived from it: Stage I: rupture of one fascicle of the collateral ligament. Passive valgus mobility of less than 15 degrees. The ruptured ends of the ligament remain in contact. Stage II: rupture of both fascicles of the ligament. Passive valgus and supination mobility of the metacarpophalangeal joint of 20 to 40 degrees. Interposition of the dorsal digital expansion between the ruptured ends of the ligament. Abnormal movements can be corrected by applying tension to the dorsal digital expansion. Stage III: rupture of both fascicles of the collateral ligament and the dorsal digital expansion. Tension from the thenar muscles causes abnormal movement and produces a fixed flexion of the metacarpophalangeal joint with hyperextension of the interphalangeal joint (Z-shaped thumb). From this the authors determine the operative indications and suggest a palliative ligamentoplasty to restore the anatomy as much as possible.

[Carpal tunnel syndrome. Electrophysiologic aspects of the natural course and after treatment]. / Syndrome du canal carpien. Aspects électrophysiologiques de l'évolution naturelle et après traitement.

Fifty-eight cases of carpal tunnel syndrome confirmed by electromyography by combined studies of motor and sensory conduction of the median nerve at the wrist have been the subject of electrical studies to assess spontaneous changes and progress after treatment. Spontaneous progress in 9 cases showed an absence of changes in electromyographic findings in general and the possibility of definite improvement or rapid spontaneous worsening. Progress after local corticosteroid injections showed a statistically significant improvement after 1 to 2 months but they also showed an overall progressive return to the previous values in 6 to 12 months. Again, progress may be either clearly favourable or unfavourable. The injection seemed to alter the natural progress only very slightly. Only after operative treatment in 17 cases was there a very obvious and often rapid statistically significant improvement. This improvement was lasting and continued for at least up to a year.

[Horizontal cubito-radial pinning in fractures of the distal radius including a postero-internal fragment]. / Brochage horizontal cubito-radial dans les fractures de l'extrémité inférieure du radius comportant un fragment postéro-interne.

The authors describe 68 articular fractures of the lower end of the radius in which a postero-medial accessory fragment was displaced. They have made a study of the anatomy and fibrous connections of the fragment and conclude that this fragment is best maintained reduced by a transverse pin passed from the ulna towards the radius. They attach great importance in such fractures to injury to the triangular radio-ulnar ligament and to inferior radio-ulnar dislocation.

[Scapholunate synostoses within the framework of congenital carpal synostoses]. / Synostoses radio-scapho-lunaires dans le cadre des synostoses carpiennes congénitales.

Modality of appearance in fetal life. Racial (certain) and congenital (probable) predisposing factors. X-ray discovery of radioscapholunate fusion after minor sprain of the wrist in a young 22 year old woman otherwise without past history. Functional study of the wrist. Analysis of six similar observations reported to date.

The importance of the posteromedial fragment and its specific pinning in fractures of the distal radius.

In fractures of the lower end of the radius, the presence of a posteromedial fragment should be recognized if present. This fragment with two articular surfaces, if not reduced, will damage the radiocarpal and inferior radioulnar articulations. The diagnosis needs to be made on 3/4 X-ray views, as the fracture is often mistaken for a Colles' fracture. The author advises reduction and fixation by a method of double pinning. By comparing two sets of statistics, the overall results are shown to be improved without more complications.