Abstract
Research Type:
Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies
Introduction/Purpose:
The modified Lapidus procedure, or 1st -TMT arthrodesis, is an effective method to correct the triplanar deformity associated with hallux valgus deformity. Multiple fixation methods have been proposed to accomplish arthrodesis; however, recent literature highlights rotational instability at the forefoot/midfoot junction which may lead to recurrence of deformity. Internal fixation bridging the 1st metatarsal-intermediate cuneiform (1MC-IC) has been proposed to decrease this recurrence. This study sought to document the magnitude of hallux valgus deformity correction and to document any associated complications and to quantify any angular recurrence of the modified Lapidus procedure with the addition of a 1MT-IC screw fixation.
Methods:
The multicenter investigation retrospectively reviewed 67 cases of 1st TMT arthrodesis with 1MT-IC fixation at two separate institutions. Radiographic assessment of the intermetatarsal angle (IMA) and hallux valgus angle (HVA) were compared on pre- and final postoperative radiographs to evaluate magnitude of deformity correction and 1st weightbearing post- and final postoperative radiographs to compare and quantify in angular recurrence over time.
Results:
Analysis demonstrated significant improvement in the median pre- to final postoperative radiographic IMA (15.5 degrees; IQR 13.4-17.7, to 5.7 degrees; IQR 4.1-7.6) (P <.001) and HVA (35.8 degrees; IQR 28.9-42.0, to 9.4 degrees; IQR 4.9-16.8) (P <.001). No radiographic recurrence of hallux valgus deformity required revision with only a slight increase in the median 1st post- to final postoperative radiographic IMA (4.9 degrees; IQR 3.7-6.8, to 5.7 degrees; IQR 4.1-7.6) (P=.006) and an insignificant improvement in the HVA (11.1 degrees; IQR 6.9-14.5 to 9.4 degrees; IQR 4.9-16.8) (P=.64). No hardware complications or removals were associated with the 1MT-IC screw.
Conclusion:
Early radiographic outcomes after triplanar 1st TMT arthrodesis demonstrated promising results in the magnitude of deformity correction. Arthrodesis supplementation with 1MT-IC fixation may diminish recurrence rates and safely enhance the reliability of hallux valgus deformity correction without the concerns of hardware related complications.
Figure 1 - Case Example
(A, Top) Preoperative weightbearing AP radiographs of the bilateral feet demonstrate significant hallux valgus deformities bilaterally with significant elevation of the IMA, HVA, and lateral translation of the sesamoids indicative of an associated pronation deformity. (B, Bottom) Postoperative (Left, 15 months; Right, 22 months) weightbearing AP radiographs of the bilateral feet demonstrate significant postoperative improvement of the IMA, HVA, and sesamoid position and robust bone consolidation after 1st TMT arthrodesis with additional 1MT-IC screw fixation. Additional Akin osteotomies were performed and demonstrate interval healing and remodeling with staple fixation.