Reduction of intermetatarsal angle after first metatarsophalangeal joint arthrodesis in patients with hallux valgus.

We present a radiographic review of 94 patients who underwent first metatarsophalangeal joint arthrodesis. The main focus of our review was to assess the change in the intermetatarsal angle (IMA). The change in the IMA was measured for the entire group and for 2 subgroups (IMA 11° to 15° and IMA >15°). The results of the angular measurements for the total data set were as follows: mean preoperative first IMA, 15.32° (range 11° to 24°), mean postoperative IMA, 9.88° (range 3° to 18°), and mean change in IMA of 5.44° (range -2° to 13°; p < .001). Group 1, with an IMA of 11° to 15°, included 52 patients, with a mean change in the IMA of 4.21° (range -2° to 9°; p < .001). Group 2, with an IMA greater than 15° (range 16° to 24°), included 42 patients, with a mean change in the IMA of 6.83° (range 2° to 13°; p < .001). The change in the preoperative to postoperative IMA in group 1 compared with that in group 2 was statistically significant (p < .001). The results of the present study have confirmed the observations of previous investigators that arthrodesis of the first metatarsophalangeal joint for hallux abducto valgus deformity results in a reduction of the IMA and that a proportionately larger reduction can be expected when the IMA is larger.