CONTRIBUTION OF THE REDUCTION VIEW, THE MODIFIED GUNTZ VIEW, AND A PEROPERATIVE TEST TO SURGICAL STRATEGY FOR HALLUX VALGUS

Abstract

Purpose: All displacements can be described with x, y, z coordinates. We propose an anterior view of the first metatarsal associated with a peroperative test to determine the precise position in the frontal plane, both statically and dynamically. Lateral release is an important step in surgical treatment of hallux valgus. Both the extent of release and the potential benefit of no release must be carefully evaluated. We propose a view allowing an assessment of the metatarsophalangeal reducibility.

Material and method: Peroperative test. This test explores cuneometatarsal laxity. We conducted a prospective study in 100 cases. A 12/100 pin was used to immobilise the first cuneiform and a 20/100 pin was placed in the base of the first metatarsal. A third distal pin in the neck was used to pivot the bone on its axis. A small protractor was used to measure the angle by projection with ±2.5° precision.

Modified Guntz view. This is a weight-bearing anterior view of the first metatarsal. The cassette is positioned posteriorly. The patient stands with the heal raised 40 mm on a 20mmx20mm plexiglass bar. The metatarsal diaphysis must appear perfectly vertical. An isosceles triangle is constructed on the articular facets; the base of the triangle is perfectly horizontal and defines the pronation-supination angle. We made 100 measurements and checked correlation with the peroperative test.

Reduction view. A Zimmer brace was used to reduce the varus metatarsus and adduct the toe. The metatarsophalangeal angle and the position of the sesamoids were used to assess reducibility.

Results: Pronation and/or pronation instability was = 10° in 96% of the patients. The reduction view enabled classifiation by three grades of reducibility.

Discussion: Our contribution is determining for correction of displacements taking into account the frontal plane. No other study has shown so clearly the existence of metatarsal pronation. We also confirmed the presence of a large proportion of cuneometatarsal instability. The extent of lateral release or the potential benefit of no release can now be assessed.

Conclusion: A certain number of failures have undoubtedly been related to neglect of the parameters studied here. It is indispensable to explore the frontal plane and the dynamic parameters before establishing indications for new flat-oblique metatarsal osteotomies using conventional or minimally invasive techniques.