Contributions of age, gender, body mass index, and normalized arch height to hallux valgus: a decision tree approach.

BACKGROUND: Hallux valgus (HV) is a common toe deformity with various contributory factors. The interactions between intrinsic risk factors of HV, such as arch height, sex, age, and body mass index (BMI) should be considered. The present study aimed to establish a predictive model for HV using intrinsic factors, such as sex, age, BMI, and arch height based on decision tree (DT) model. METHODS: This is retrospective study. The study data were based on the fifth Size Korea survey, of the Korea Technology Standard Institute. Among 5,185 patients, 645 were excluded due to unsuitable age or missing data, and 4,540 (males = 2,236 and females = 2,304) were selected for inclusion in the study. Seven variables (i.e., sex, age, BMI, and four normalized arch height variables) were used to develop the prediction model for the presence of HV using a DT model. RESULTS: The DT model correctly classified 68.79% (95% confidence interval [CI] = 67.25-70.29%) of the training data set (3,633 cases). The predicted presence of HV based on the DT was verified against the testing data set (907 cases) and showed an accuracy of 69.57% (95% CI = 66.46-72.55%). CONCLUSIONS: The DT model predicted the presence of HV on the basis of sex, age, and normalized arch height. According to our model, women aged over 50 years and those with lower normalized arch height were at high risk of HV.

Radiographic Assessment of Relationship Between Medial Cuneiform Obliquity and Hallux Valgus.

The research results are inconsistent that assessing whether the increased obliquity of the distal articular surface of the medial cuneiform leads to an increase in hallux valgus angle. Thus, this study investigated the relationship between distal medial cuneiform obliquity and hallux valgus by measuring various angles in weightbearing anteroposterior radiographs of the foot. In total, 679 feet of 538 patients with the radiographs were included in the study. We measured radiographic parameters including hallux valgus angle, first to second intermetatarsal angle, metatarsus adductus angle, first metatarsus cuneiform angle, distal medial cuneiform angle, and first proximal metatarsal articular angle. The surface morphology (flat or curved) of the first tarsometatarsal joint was also recorded. Our results analysis revealed a weak negative correlation between distal medial cuneiform angle and both hallux valgus angle and first to second intermetatarsal angle, contrary to our assumption. So we believe that distal medial cuneiform angle was relatively constant and it cannot be used as a characteristic angle for quantifying hallux valgus. First metatarsus cuneiform angle was a characteristic indicator of hallux valgus and was positively correlated with its severity (p < .000), indicating that it can be used to measure the size of hallux valgus. It can also be used as a reference factor for the first metatarsal osteotomy in clinical bunion orthopedics. First tarsometatarsal joint morphology was unrelated to hallux valgus, whereas metatarsus adductus angle, and first proximal metatarsal articular angle should be considered in hallux valgus.

Intra­ and Interobserver Reliability of Yamaguchi's Method for the Assessment of First Metatarsal Pronation in Hallux Valgus Deformity.

Pronation of the first metatarsal is a risk factor for the formation and progression of the hallux valgus deformity. Recently, Yamaguchi et al published a study that showed how the round sign increases on digitally reconstructed radiography taken from a CT scan when pronation is applied. In this study, the shape of the lateral edge of the first metatarsal head was evaluated on weightbearing dorsoplantar radiographs. Yamaguchi's signs were presented to observers after the visual presentation of each foot as an image. The best-fit circle was drawn using the PACS drawing function. Ninety radiographs of adults presenting hallux valgus deformities were classified as mild-to-moderate, based on hallux valgus angle and intermetatarsal angle. The global average observations were 3.72 ± 3.92 (range 2.3°-4.6°). The interclass correlation (Fleiss Kappa index κ = 0.225) and the Spearman correlation (0.16 of Kappa) coefficients were poor for interobserver measurements and statistically significant. Using the linear model, there was no significant variability between the repetitions corresponding to each observer (t-value -1.527, p value .127). Our findings show that the Yamaguchi method can be very subjective and should not be the exclusive technique to assess the rotation of the first metatarsal or head roundness.

Patients With Opioid Use Disorder Have Increased Readmission Rates, Emergency Room Visits, and Costs Following a Hallux Valgus Procedure.

BACKGROUND: Patients with a history of opioid use disorder (OUD) tend to have more complications, higher readmission rates, and increased costs following orthopaedic procedures. This study evaluated patients undergoing hallux valgus correction for their odds of increased (1) readmission rates, (2) emergency room (ER) visits, and (3) costs. METHODS: Patients undergoing hallux valgus corrections with OUD history were identified using a national Medicare administrative claims database of approximately 24 million orthopaedic surgery patients. OUD patients were matched to non-opioid use disorder (NUD) patients in a 1:4 ratio by age, sex, Elixhauser-Comorbidity Index (ECI), diabetes mellitus, hyperlipidemia, hypertension, and tobacco use. The query yielded 6318 patients (OUD = 1276; NUD = 5042) who underwent a hallux valgus correction. Primary outcomes analyzed included odds of 90-day readmission rates, 30-day ER visits, and 90-day episode-of-care costs. Demographics, odds ratios (ORs), ECI, and cost were assessed as appropriate using a Pearson χ2 test, logistic regression, and a t test. A P value <.05 was considered statistically significant. RESULTS: There were no significant differences in demographics between OUD and NUD patients. OUD patients had higher incidence and odds of 90-day readmission (9.56% vs 6.04%; OR = 1.55; P < .001) and 30-day ER visits (0.86% vs 0.35%; OR = 2.42; P = .021) and incurred greater 90-day episode-of-care costs ($7208.28 vs $6134.75; P < .001) compared with NUD patient controls. CONCLUSION: The study demonstrates the possible influence of OUD on higher odds of readmission, ER visits, and costs following a hallux valgus correction. LEVELS OF EVIDENCE: Level III: Retrospective cohort study.

Distal Metatarsal Articular Angle in Hallux Valgus Deformity. Fact or Fiction? A 3-Dimensional Weightbearing CT Assessment.

BACKGROUND: The Distal Metatarsal Articular Angle (DMAA) was previously described as an increase in valgus deformity of the distal articular surface of the first metatarsal (M1) in hallux valgus (HV). Several studies have reported poor reliability of this measurement. Some authors have even called into question its existence and consider it to be the consequence of M1 pronation resulting in projection of the round-shaped lateral edge of M1 head.Our study aimed to compare the DMAA in HV and control populations, before and after computer correction of M1 pronation and plantarflexion with a dedicated weightbearing CT (WBCT) software. We hypothesized that after computerized correction, DMAA will not be increased in HV compared to controls. METHODS: We performed a retrospective case-control study including 36 HV and 20 control feet. In both groups, DMAA was measured as initially described on conventional radiographs (XR-DMAA) and WBCT by measuring the angle between the distal articular surface and the longitudinal axis of M1. Then, the DMAA was measured after computerized correction of M1 plantarflexion and coronal plane rotation using the α angle (3d-DMAA). RESULTS: The XR-DMAA and the 3d-DMAA showed higher significant mean values in HV group compared to controls (respectively 25.9 ± 7.3 vs 7.6 ± 4.2 degrees, P < .001, and 11.9 ± 4.9 vs 3.3 ± 2.9 degrees, P < .001).Comparing a small subset of precorrected juvenile HV (n=8) and nonjuvenile HV (n=28) demonstrated no significant difference in the measure DMAA values. On the other hand, the α angle was significantly higher in the juvenile HV group (21.6 ± 9.9 and 11.4 ± 3.7 degrees; P = .0046). CONCLUSION: Although the valgus deformity of M1 distal articular surface in HV is overestimated on conventional radiographs, comparing to controls showed that an 8.6 degrees increase remained after confounding factors' correction. CLINICAL RELEVANCE: After pronation computerized correction, an increase in valgus of M1 distal articular surface was still present in HV compared to controls. LEVEL OF EVIDENCE: Level III, retrospective case-control study.

Cost-Utility Study of the Economics of Bunion Correction Surgery.

BACKGROUND:: Bunion correction surgery is a very common procedure to improve patients' pain and physical function attributable to a misaligned first metatarsophalangeal joint. The objective of this study was to apply a health utility framework to estimate the cost utility of bunion correction surgery. METHODS:: Patients were prospectively recruited from the population of patients seen in a lower-extremity orthopedic clinic and scheduled for isolated bunion surgery. Participants completed EuroQoL's EQ-5D(3L) to measure patients' current general health preoperatively and 6 months postoperatively. Participants' change in quality-adjusted life years (QALYs) were calculated by comparing the difference between postoperative utility values and preoperative utility values. The study had 95 patients representing 53% of eligible patients. RESULTS:: The mean preoperative utility value was 0.6816 and the mean postoperative value was 0.7451, a statistically significant difference denoting an improvement in self-reported health. The cost per QALY, assuming gains in health accrued for 15 years, was $4911 (the 95% confidence interval ranged from $4736 to $5088). The cost per QALY was highest among the oldest patients. Assuming gains in health accrued for 20 years, the cost per QALY was $3922. CONCLUSION:: This study demonstrated that bunion correction surgery was inexpensive relative to its gains in health compared with commonly applied thresholds for women and men in all age groups, though the gains were not uniformly distributed across age categories. Future research should examine the impact of recurrence on the robustness of these findings. LEVEL OF EVIDENCE:: Level III, comparative study.

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.