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

Correlation of Clinical Outcomes and Relative Position of the First Metatarsal After the Modified Lapidus Procedure

BACKGROUND

Hallux valgus is a complex 3-dimensional deformity, and the modified Lapidus is a commonly used procedure to correct moderate to severe cases. Shortening and elevation of the first ray can occur with this procedure, which may result in increased pressure on the lesser metatarsal heads. However, there is currently no consensus regarding an accepted length and elevation of the first ray following the modified Lapidus. Therefore, the purpose of this study is to evaluate the impact of the position of the first ray on patient-reported outcome measures.

METHODS

This retrospective study identified 68 patients (72 feet) who underwent the modified Lapidus bunionectomy over a 4-year period at a single institution with a median follow-up of 24 months (range, 11-35.6 months). Patients were included if they were over 18 years of age, had pre- and postoperative weightbearing computed tomography (WBCT) scans, and preoperative and minimum 1-year postoperative Patient-Reported Outcome Measurement Information System (PROMIS) scores. PROMIS scores from 6 domains including physical function, pain interference, pain intensity, global physical health, global mental health, and depression were evaluated and compared pre- and postoperatively. Radiographic parameters were measured and compared before and after surgery. Paired t tests were used to evaluate the significance of pre- to postoperative changes. Differences between cohorts were compared using Mann-Whitney U test for continuous variables or Fisher exact test for categorical variables. Correlation between radiographic measurements and patient-reported outcomes were assessed using the Spearman rank rho estimate and visualized with scatterplots with a linear regression.

RESULTS

PROMIS physical function, pain interference, pain intensity, and global physical health improved significantly following the modified Lapidus (all P < .001); however, scores did not show any significant correlation with shortening of the first ray up to a maximum shortening of 4.8 mm. The length of the first metatarsal relative to the second decreased by an average of 2.7 mm following the procedure when measured on WBCT (P < .001), and 2.6 mm when measured on plain radiographs (P < .001). No significant elevation of the first ray was observed postoperatively.

CONCLUSION

This study revealed that the Lapidus bunionectomy resulted in significantly improved pain and physical function at short-term follow-up. The amount of first ray shortening and elevation that occurred in this cohort did not adversely affect patient-reported outcomes.

Does the Presence of Asymptomatic Flatfoot Deformity Impact the Clinical and Radiographic Outcomes of the Minimally Invasive Chevron and Akin Bunionectomy?

BACKGROUND

Flatfoot deformity is believed to play a role in hallux valgus development and recurrence. While symptomatic flatfoot deformity can be treated with separate procedures at the time of hallux valgus correction, the question remains whether the patient undergoing correction of a symptomatic hallux valgus deformity should have their asymptomatic flatfoot concurrently addressed. We aimed to investigate whether the presence of asymptomatic flatfoot influences patient-reported and radiographic outcomes of the minimally invasive chevron and Akin bunionectomy.

METHODS

A total of 104 patients were included in this study. Forty-two asymptomatic patients met the radiographic criteria for flatfoot while 62 had a normal arch. Patient-reported outcomes were evaluated and compared between the two groups using validated PROMIS measures preoperatively and at a minimum one-year postoperatively. Radiographic outcomes including hallux valgus angle (HVA), intermetatarsal angle (IMA), Meary's angle, calcaneal pitch (CP), and talonavicular coverage angle (TNCA) were measured and compared preoperatively and minimum six-months postoperatively.

RESULTS

Both groups demonstrated similar preoperative and postoperative PROMIS scores with significant improvements in physical function, pain interference, pain intensity, and global physical health. Preoperatively, HVA was similar between both groups, however the flatfoot group showed a greater IMA, Meary's angle, TNCA, and lower CP. Postoperatively, HVA and IMA were similar between groups, although patients in the flatfoot group retained a significantly greater Meary's angle, TNCA, and lower CP. Both groups showed significant improvements in HVA, IMA, and TNCA.

CONCLUSION

Our study indicates that the minimally invasive chevron and Akin bunionectomy leads to improved clinical and radiographic hallux valgus outcomes without adversely impacting radiographic flatfoot parameters. Therefore, the MIS bunionectomy may be an effective option for hallux valgus correction in patients with mild, asymptomatic flatfoot.

LEVEL OF EVIDENCE

Level III, retrospective cohort.