Effect of the First Tarsometatarsal (Modified Lapidus) Arthrodesis on Hindfoot Alignment

Addressing Medial Column Instability in Flatfoot Deformity

A stable medial column is important to the normal function of the foot and ankle. Medial column instability and forefoot varus can result in compensatory hindfoot motion leading to stress along the medial soft-tissue structures. Medial column stabilization should therefore be considered when (1) forefoot varus deformity is identified following hindfoot realignment; (2) pronounced medial column instability is present, even in the absence of forefoot varus; and (3) when degenerative changes are present within the medial column articulations. Common surgical procedures include arthrodesis of the talonavicular joint, naviculocuneiform joint, and first tarsometatarsal joint, as well as osteotomy of the medial cuneiform (Cotton osteotomy).

Definitions and Measurements of Hindfoot Alignment and Their Biomechanical and Clinical Implications

This article presents a critical review of the past and the current state of the art in defining and measuring hindfoot, ankle, and subtalar alignment. It describes the transition occurring at present from two-dimensional to three-dimensional (3D) alignment measurements, which accompany the emergence of new, functional, high-resolution imaging modalities such as the weight-bearing cone-beam computerized tomography (CT) imaging. To ease and enhance the transition and acceptability of 3D alignment measurements, new acceptable standards for different clinical application are highly desirable.

First Tarsometatarsal Joint Arthrodesis for Hallux Valgus With and Without Intermetatarsal Screw Fixation: A Comparison of Correction and Maintenance of Correction

Tarsometatarsal joint arthrodesis is a commonly accepted procedure for hallux valgus associated with severe deformity and first ray hypermobility or medial column instability. This study evaluates the correction of hallux valgus deformity and the maintenance of correction with and without the use of a stabilization screw between the first and second metatarsal bases. Through retrospective review of first tarsometatarsal joint arthrodesis within our institution we evaluated 63 patients. Twenty-seven patients did not have a first to second metatarsal base screw and were placed into the no screw cohort. Thirty-six patients did have a first to second metatarsal base screw and were placed into the screw cohort. This study population had an osseous union rate of 95%. Clinical and radiographic recurrence occurred in 5 of 63 patients (8%). At 1-y postop the measurements demonstrated that the screw cohort had an average intermetatarsal angle correction of 11.6 degrees while the no screw cohort had an average correction of 7.8 degrees. Additionally, at 1-y postop the screw cohort had greater maintenance of the intermetatarsal angle correction with an average change of 0.5 degrees compared to 2.3 degrees in the no screw cohort. We conclude that the addition of the stabilization screw improves the first tarsometatarsal joint arthrodesis construct resulting in a greater degree of realignment and maintenance of correction.

Impact of Asymptomatic Flatfoot on Clinical and Radiographic Outcomes of the Modified Lapidus Procedure in Patients With Hallux Valgus

Background

Patients with hallux valgus commonly present with concomitant flatfoot deformity. First-ray hypermobility, among other biomechanical factors, has been suggested as a potential link between these deformities. However, not all hallux valgus patients exhibit symptoms associated with flatfoot deformity, and the necessity of correcting the asymptomatic flatfoot at the time of hallux valgus correction is unclear. We aimed to investigate the relationship between asymptomatic flatfoot and patient-reported and radiographic outcomes after the Lapidus procedure.

Methods

This study included 142 patients who underwent the Lapidus procedure for hallux valgus at a single institution. Sixty-one patients met radiographic criteria for flatfoot. No patients exhibited symptoms related to flatfoot deformity on review of clinical notes. Preoperative, minimum 1-year postoperative, and change in Patient-Reported Outcomes Measurement Information System (PROMIS) scores between asymptomatic flatfoot and control groups were compared. Radiographic outcomes including hallux valgus angle (HVA), intermetatarsal angle (IMA), Meary angle, talonavicular coverage angle (TNCA), and calcaneal pitch (CP) were compared.

Results

Preoperatively, the flatfoot group had higher BMI 22.6 vs 24.6 (P < .01) and IMA 15.32 vs 14.0 degrees (P < .05). Both groups demonstrated preoperative to postoperative improvement in PROMIS physical function (P < .01), pain interference (P < .001), pain intensity (P < .001), and global physical health (P < .001). There were no preoperative or postoperative differences in PROMIS scores between groups. Postoperatively, there were no differences in HVA or IMA between groups; however, the flatfoot group exhibited greater deformity in Meary angle, TNCA, and CP (all P < .001).

Conclusion

There were no significant postoperative differences in patient-reported outcomes of the Lapidus procedure between patients with and without asymptomatic flatfoot, and both groups achieved similar radiographic correction of their hallux valgus deformity. The Lapidus procedure appears to be a reasonable surgical option for hallux valgus correction in patients with asymptomatic flatfoot deformity.Level of Evidence: Level III, retrospective cohort study.