CHANGE IN INTERMATATARSAL ANGLE OF HALLUX VALGUS FOLLOWING FIRST METATARSOPHALANGEAL ARTHRODESIS

Abstract

Background: First Metatarsophalangeal joint (MTP) arthrodesis is commonly performed for hallux valgus with an arthritic joint, however previous studies have recommended that this should be combined with another procedure to correct the hallux valgus when the intermetatarsal angle is enlarged. We propose that an arthrodesis of the first MTP joint with a soft tissue release produces a significant correction of the intermetatarsal angle in such a group of patients avoiding the need for a concomitant procedure to change the intermetatatarsal angle.

Patients and Methods: The charts and radiographs of 20 patients who had an arthrodesis of the first MTP joint were retrospectively reviewed. All 20 patients were female with a mean age of 54.2 years (range 42–78 years). The intermetatarsal (IMT) angles were measured by two individuals independently. These were measured on a weight-bearing pre-operative film and a weight-bearing 6-week post-operative film. Fusions were performed using either the Hallu-S® plate or two crossed screws. A Student “t” test was performed on the change of the IMT angle and also on the inter-observer variations for the same.

Results: The mean pre-operative IMT angle was 16.85° (range 12–30°). The mean post-operative IMT angle was 10.6° (range 6–20°). The mean change in the IMT angle was 6.25° (range 2–12°). This change of the IMT angle was statistically significant – p< 0.0001 – Student “t” test. There was no significance in the inter-observer difference (p> 0.5) note in 6 radiographs with a mean of 1.3° (range 1–2°).

Conclusion: This is the first study to show that performing an arthrodesis of the first MTP joint with soft tissue release in patients with hallux valgus and degenerate first MTP joint will significantly correct the IM angle. Therefore, this alleviates the need for performing another procedure on these patients.