Weightbearing Computed Tomography and 3-Dimensional Analysis of Mobility Changes of the First Ray After Proximal Oblique Osteotomy for Hallux Valgus.

BACKGROUND: Hypermobility of the first ray has been evaluated using various methods and has conventionally been considered to be involved in the pathology of hallux valgus. We hypothesized that hypermobility of the first ray in hallux valgus could be decreased by simply correcting foot alignment without arthrodesis. This study sought to evaluate first-ray mobility using weightbearing computed tomography (CT) before and after proximal oblique osteotomy and also in healthy volunteer's feet. METHODS: Subjects were 11 feet of 11 patients with primary hallux valgus who underwent surgery with a plantarly applied anatomic precontoured locking plate and 22 feet of 11 matched healthy volunteers. We performed nonweightbearing and weightbearing (using a load equivalent to body weight) CT scans using an original loading device preoperatively and 1-1.5 years postoperatively. Three-dimensional displacement of the distal bone relative to the proximal bone was quantified for each joint of the first ray by comparing nonweightbearing and weightbearing CT images. RESULTS: At baseline, there were significant differences in hallux valgus angle (P < .001) and 1-2 intermetatarsal angle (P < .001) between healthy volunteer's feet and preoperative hallux valgus feet. Hallux valgus angle (P < .001) and 1-2 intermetatarsal angle (P < .001) differed significantly between before and after surgery. All first ray joint displacement under loading decreased postoperatively to within 2° of that in healthy volunteer's feet and showed no significant difference between postoperatively hallux valgus feet and healthy volunteer's feet (P > .05). CONCLUSIONS: We found that first metatarsal osteotomy even without arthrodesis corrected deformity and decreased mobility of the first ray after hallux valgus surgery. LEVEL OF EVIDENCE: Level III, case-control study.

Pes Planus Deformity and Its Association With Hallux Valgus Recurrence Following Scarf Osteotomy.

BACKGROUND: Hallux valgus recurrence is an unsatisfactory complication, with many causes postulated. This study investigated the effect of pes planus on recurrence after scarf osteotomy. METHODS: A total of 183 feet were retrospectively reviewed. All patients were treated with a scarf osteotomy and if required Akin osteotomy. We measured preoperative lateral talus first metatarsal angle (T1MA) to study pes planus; an angle of under -4 degrees was considered pes planus. We measured pre and postoperative hallux valgus angle (HVA), intermetatarsal angle (IMA), and sesamoid location. In total 164 feet were suitable for inclusion, with follow-up of at least 6 months (10 males and 154 females, mean age: 52 years). RESULTS: Recurrence frequency (HVA greater than 15 degrees) was 27 feet (16%). Hallux valgus recurrence was not influenced by gender (P value = .66) or preoperative IMA (P value = .48). Preoperative HVA greater than 35 degrees was associated with increased frequency of recurrence (P value = .004). Those with T1MA less than -10 degrees demonstrated progression in HVA and deterioration in sesamoid location up to 6 months postoperatively (P value = .038). HVA did not progress beyond 6 months. The prevalence of recurrent hallux valgus with normal T1MA was 1%, in T1MA -4 to -10 degrees it was 29% and in T1MA less than -10 degrees it was 47% (P value <.001). Breaks in T1MA less than -4 degrees were found at the naviculocuneiform joint in 68% of feet in this series. CONCLUSION: The prevalence of hallux valgus recurrence correlated with the severity of pes planus. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Validating the Foot and Ankle Outcome score for measuring foot dysfunction among hallux valgus surgery patients using item response theory.

BACKGROUND: There is an absence of high quality research validating instruments that measure foot and ankle related quality of life among hallux valgus (bunion) patients' perspectives. The Foot and Ankle Outcome Scale is a patient-reported outcome instrument, that when administered to patients with symptomatic hallux valgus, provides a patient-centric perspective of their foot function. The aim of this study is to assess the psychometric properties of the instrument's five subscales among preoperative bunion surgery patients. METHODS: The Foot and Ankle Outcome Scale instrument measures Pain, Symptoms, Activities of Daily Living, Sport and Recreational Activities and Foot/Ankle Related Quality of Life. Preoperative data is collected from a sample of patients scheduled for surgical treatment of their condition in Vancouver, Canada. Classical and item response theory methods are used to report on reliability, validity and differential item functioning among subgroups. RESULTS: This study included 249 surveys, representing an overall response rate of 44.1% among 564 eligible patients. The instrument demonstrated high reliability for all subscales, though 18 items across subscales, exhibited poor discrimination between item levels. Four items score differently according to patients' sex and one item scored differently by age. CONCLUSIONS: The instrument measures five domains of health important to bunion patients. These findings suggest that the current instrument can be used with an understanding of its limitations, including redundant questions and sex-based differences. Future research should revise a number of items. The results highlight the importance of the psychometric analyses of instruments in specific patient populations.

Weightbearing CT Scan Assessment of Foot Alignment in Patients With Hallux Rigidus.

BACKGROUND: An association between hallux rigidus and metatarsus primus elevatus (MPE) has been suggested, although there remains no general consensus about the nature of this relationship. Past studies were limited due to inaccuracies of assessing MPE on 2-dimensional radiographs. The aims of this study were to (1) assess and compare foot alignment in patients with and without hallux rigidus using 3-dimensional (3D) reconstructions from weightbearing computed tomography (CT) and (2) assess intraobserver and interobserver reliability of these measurements. METHODS: A prospective study was performed in 50 consecutive patients with symptomatic hallux rigidus and 50 control patients who underwent a weightbearing CT. Two investigators measured first and second metatarsal declination angles, first and second metatarsal lengths, first to second intermetatarsal angle (IMA), hallux valgus angle (HVA), and foot width on 3D CT reconstructions. Measurements were repeated after 1 month. Student t tests were performed to compare hallux rigidus and control groups. Intraclass and interclass correlation coefficients were calculated to evaluate reliability. RESULTS: The first to second metatarsal declination ratio was less in patients with hallux rigidus (mean, 0.81) than controls (mean, 0.92; P < .001). Patients with Coughlin and Shurnas grade 3 and 4 hallux rigidus had greater first metatarsal declination than patients with grade 1 and 2 hallux rigidus. Last, IMA was higher (mean, 13 degrees) but HVA was lower (mean, 11 degrees) in patients with hallux rigidus than controls (IMA mean, 12 degrees; HVA mean, 15 degrees; P = .04). Intraobserver (ICC1,1 ≥ 0.93) and interobserver (ICC3,1 ≥ 0.85) reliability were good to excellent for all measured parameters. CONCLUSIONS: Patients with hallux rigidus had MPE. Patients with grade 3 and 4 hallux rigidus had more MPE than patients with grade 1 and 2 hallux rigidus. There was no clear correlation between hallux rigidus and bunions. Finally, weightbearing CT proved to be a reliable method of assessing all measured parameters. LEVEL OF EVIDENCE: II, prospective comparative series.