Correlation of Preoperative Radiographic Severity With Disability and Symptom Severity in Hallux Valgus

We conducted a retrospective analysis of patients who presented for elective hallux valgus operative correction in our practice during the last 2 years. All data were already in existence at the time of the study. Exempt determination and HIPAA waiver was obtained from our local institutional review board. Eligible subjects had to have Foot and Ankle Outcome Score (FAOS) completed preoperatively with respect to their operative foot. In our practice, FAOS data were typically obtained on many of our operative patients to help with clinical decision making and to monitor postoperative progress. The FAOS is a validated patient-based tool for evaluating postoperative hallux valgus operative outcomes that has demonstrated internal consistency, convergent validity, and structural validity.⁵ The survey consists of 42 items and 5 subscales: pain, symptoms, function/activities of daily living, function/sport and recreation, and foot and ankle–related quality of life. Subscale scores are reported on a scale that ranges from 0 to 100, with higher values indicating better scores (eg, less pain, fewer symptoms, higher functioning).

Included subjects also had to have preoperative weightbearing foot radiographs, and enough pain and disability with their bunion that they proceeded with hallux valgus surgery between January 1, 2016, and July 1, 2018. Similarly, surgeons had to have felt their patient’s symptoms and/or overall foot morphology required osseous realignment (via osteotomy or arthrodesis), as opposed to simple ostectomy of the first metatarsal head. In order to avoid the confounding effect of other foot/ankle deformities unrelated to the bunion, we restricted our sample by excluding patients who also complained of hammertoes, forefoot metatarsalgia requiring lesser metatarsal osteotomies, and/or required other surgery outside of hallux valgus correction. In patients who sought treatment for bilateral hallux valgus during the study, we selected the foot with the lowest FAOS total score for inclusion as the study foot, making the subject the unit of observation (rather than the foot) as has previously been recommended.

There were complete data from 107 patients (107 feet) with a mean age of 49.3 ± 13.8 years and mean body mass index of 25.2 ± 4.8 who sought treatment and subsequently underwent surgery for isolated hallux valgus during the study period. One hundred two participants were women (102/107, 95%), and 106 identified as white (106/107, 99%). Patients included in the study underwent scarf/Akin osteotomies (n=85), scarf osteotomies only (n=19), Lapidus procedures (n=2), or chevron (n=1) osteotomies in their study foot.

All radiographs were evaluated by a single rater (M.M.) using commercially available software. The following parameters were evaluated on plain films: the first and second intermetatarsal (IM) angle, the hallux valgus (HV) angle, metatarsus adductus angle via the Engels angle, metatarsal protrusion distance using Nilsonne’s method, and tibial sesamoid position using the method of Hardy and Clapham (Figure 1). Engle’s method for measuring the metatarsus angle describes the angle between the longitudinal bisection of the second metatarsal and the longitudinal bisection of the second cuneiform (as opposed to using the longitudinal axis of the lesser tarsus). Nilsonne’s method of examining metatarsal protrusion distance involves measuring the distance in millimeters between a perpendicular line to the longitudinal axis of the second metatarsal at the most distal point of the second metatarsal head to a parallel line that passes through the distalmost point of the first metatarsal head (Figure 1).