Intermetatarsal Angle Measurements Research Articles

Assessment of the Initial Result of Screw Fixation for Proximal Crescentic Metatarsal Osteotomy with Distal Soft Tissue Reconstruction in Severe Hallux Valgus Treatment.

Proximal crescentic metatarsal osteotomy and distal soft tissue reconstruction have been introduced to correct severe HV. The intrinsically unstable proximal first crescentic osteotomy depends on enough force fixation for stability. It is necessary to judge the number of fixation screws for osteotomy. Fifty-two feet of 50 adult patients with severe HV were included in this study. The treatment was proximal crescentic metatarsal osteotomy with a single screw and distal soft tissue reconstruction in Group 1 and the fixation with two screws with distal soft tissue reconstruction in Group 2. Clinical and radiological follow-ups were assessed after 4 and 12 months of operation. In Group 1, HVA decreased from 46.4 ±3.28 to 19.9 ±4.70 after 12 months of operation and from 45.1 ±3.45 to 19.1 ±4.70 in Group 2. Regarding the intermetatarsal angle (IMA) in Group 1, it was changed from 18.5 ±1.98 to 9.25 ±1.11 after 12 months of operation. For group 2, it decreased from 18.3 ±1.81 to 9.53 ±1.70. Meanwhile, the AOFAS score improved from 63.1 to 83.9 after 12 months of operation in Group 1 and improved from 64.3 to 82.8 in Group 2. Furthermore, the VAS score reduced from 4.5±1.01 to 1.7± 0.43 in Group 1 and from 4.7±0.92 to 1.7±0.55 in Group 2 after 12 months of operation. There were no significant differences identified between Group 1 and Group 2 in terms of VAS and AOFAS scores and HVA and IMA measurements. There is less complication in two-screw fixation for crescentic osteotomy compared to a single-screw fixation.

A Case-Control Study of 3D vs 2D Weightbearing CT Measurements of the M1-M2 Intermetatarsal Angle in Hallux Valgus.

Weightbearing computed tomography (WBCT) 3-dimensional measurements may be reliable in assessing hallux valgus (HV). The objective of this study was to compare 2D and 3D WBCT measurements of the M1-M2 intermetatarsal angle (IMA) in patients with HV and in healthy controls. We hypothesized that 2D and 3D IMA measurements would correlate and have similar reliability in both HV and controls. Retrospective multicenter comparative study included WBCT scans from 83 feet (41 HV, 42 controls). IMA was measured on digitally reconstructed radiographs (DRR-IMA). 3D angle (3D-IMA) and its projection on the weightbearing plane (2D-IMA) were calculated from 3D coordinates of the first and second metatarsals. Intraobserver reliability and intermethod correlations were calculated using intraclass correlation coefficients (ICCs). Intraobserver reliability was very strong for DRR-IMA (0.95) and 3D-IMA (0.99). Intermethod correlation between the 3 modalities in HV patients ranged from moderate (DRR vs 2D, 0.48; DRR vs 3D, 0.48) to very strong (2D vs 3D, 0.91). Similarly, intermethod correlation in the control group ranged from moderate (DRR vs 2D, 0.56; DRR vs 3D, 0.60) to very strong (2D vs 3D, 0.92). Measurements for IMA are similar using DRR, 3D and 2D projected angles, with very strong intraobserver reliability and moderate to very strong intermethod correlations. This is the first head-to-head comparison between these measurement modalities in HV. Further investigations are warranted before formulating guidelines for the clinical use of 3D angles. Level III, case-control study.

Evaluation of a Weightbearing CT Artificial Intelligence-based Automatic Measurement for Hallux Valgus: A Case-Control Study

Category:Bunion; OtherIntroduction/Purpose:Cone Beam Weight Bearing CT (WBCT) is gaining traction, particularly in the foot and ankle, due to the ability to perform natural stance weight bearing 3D scans. However, the resulting wealth of 3D data renders daily clinical use time consuming. Therefore, reliable automatic measurements are indispensable in order to make best use of the technology. The aim of this study was to evaluate a beta-version WBCT artificial intelligence (AI) automatic measurement system for the M1-M2 intermetatarsal angle (IMA), which is applicable in the absence of metallic hardware in the foot and ankle. We hypothesized that automatic measurements would correlate well with human measurements, and that software reproducibility would be better and close to perfect compared to manual measurements.Methods:In this retrospective case-control study, 90 feet were included from patients who underwent WBCT scans during routine follow up: 44 feet (90.9% female, mean age 54 years) with symptomatic hallux valgus (HV), 46 controls (76.1% female, mean age 49 years). Patients were excluded if they had history of surgery or trauma involving the first or second metatarsals, hallux rigidus, or presence of metal in their foot/ankle. IMA was measured manually on Digitally Reconstructed Radiographs (DRR IMA) and automatically with AI software producing auto 2D (ground plane projection) and 3D (multiplanar) measurements. Each IMA DRR was measured by two independent raters twice to calculate intraclass correlation coefficients (ICCs). To assess intra- software reliability, AI software measurements were made twice on each dataset. Manual and automatic measurements were compared between HV and control groups. Failures of the AI software to produce a measurement were recorded.Results:Mean values for controls were 8.6° +-1.8° (range, 5°-14°) for the manually measured DRR IMA, 9.3° +-2.8° (range, 3°- 17°) for auto 2D, and 9.2° +-2.6° (range, 3°-16°) for auto 3D IMA measurements. Compared to controls, HV patients demonstrated significantly increased IMA (p<0.0001): 14.2° +-2.7° (range, 8°-21°) for the manually measured DRR IMA, 15.4°+- 4.4° (range, 8°-26°) for auto 2D, and 15.1° +-4.1° (range 8°-28°) for auto 3D IMA measurements. There were strong correlations (r=0.75 and r=0.80) between manual and auto 2D and 3D measurements. Intraobserver and interobserver ICCs for DRR IMA were 0.96 and 0.90, respectively, and the intra-software ICCs for the AI were near 1.0 for both auto 2D and auto 3D IMA. The AI software failed in 32.3% cases.Conclusion:Our results demonstrated strong correlation between a WBCT Artificial Intelligence based automatic measurement for IMA with human measurements, with the ability to distinguish HV from control with close to 100% repeatability. However, the number of failures was still high due to the early stage beta-version of the algorithm tested. While these early results are promising, further developments are warranted in order to improve usability of this tool in daily practice, especially in the presence of metal hardware.Figure 1.

A Comparison Between X-ray Imaging and an Innovative Computer-aided Design Method Based on Weightbearing CT Scan Images for Assessing Hallux Valgus

With the development of recent technology, radiographs can be saved digitally, and angular measurements can be processed using various software packages. We developed an innovative computer-aided design method with Materialize Interactive Medical Image Control System software to measure hallux valgus angle (HVA), the intermetatarsal angle (IMA), and the distal metatarsal articular angle (DMAA) and assessed its concordance with traditional X-ray imaging methods. All measurements were carried out on 42 feet from 26 adult patients diagnosed with hallux valgus who were prospectively selected from July 2016 to April 2018. Standing X-ray radiograph and weightbearing computed tomography scans were conducted on all patients, and HVA, IMA, and DMAA were generated using both a traditional X-ray method and our innovative method. Two different observers assessed measurements for each patient. Finally, statistical analyses were conducted to assess the reliability of the measurements. Both X-ray imaging and our innovative method had strong interobserver and test-retest reliability. The ICC of X-ray imaging was 0.945, p < .001, and the ICC of the innovative method was 0.915, p < .001. There was no statistical difference between the 2 methods for HVA and IMA measurements (p > .05); however, a difference was detected for DMAA (p < .05). Bland-Altman analyses demonstrated a high degree of agreement between the 2 methods for HVA and IMA, but a significant difference for DMAA. From the results, we concluded that our innovative computer-aided design method is a feasible, reliable way to quantitatively assess HVA, IMA, and DMAA, and it is likely more accurate for measuring DMAA.

A Case-control Study of 3D versus 2D Weight Bearing CT Measurements of the M1-M2 Intermetatarsal Angle in Hallux Valgus

Category: Midfoot/Forefoot Introduction/Purpose: Surgical planning based on angular measurements obtained on conventional radiographs is challenging due to perspective distortion and operator bias. Novel weightbearing CT (WBCT) three-dimensional (3D) measurements using coordinate systems may represent a more reliable and accurate evaluation of this 3D deformity. The objective of this study was to compare the M1-M2 intermetatarsal angle (IMA) obtained manually on WBCT digitally reconstructed 2D radiographs versus a set of coordinates from the full 3D dataset, in patients with hallux valgus (HV) deformity and in healthy controls. We hypothesised that the 3D measurements would be more reliably obtained, demonstrating different values when compared to 2D radiographic measurements. Methods: In this multicenter retrospective comparative study, 83 feet that underwent WBCT of the foot were included (41 HV: mean age 59, 81% female, 42 controls: mean age 52, 80% female). Datasets were analysed by three independent trained foot and ankle surgeons using the same protocol. Coordinates in three planes (x, y, z) of four different landmark points were harvested: center of the heads and midpoint of the proximal metaphysis of the 1st and 2nd metatarsal. The IMA measurements were then performed in reconstructed radiographic images (DRR-IMA). The data collected was then analyzed by a single 4th independent and blinded investigator who calculated the 3D angle (3D-IMA) and its projection on the weightbearing plane (2D-IMA). Intra-observer realiability was assessed by Pearson/Spearman’s correlation. Intermethod correlation was evaluated by intraclass correlation coefficient (ICC). Mean values for measures were comparared by One-way ANOVA. P-values of less than 0.05 were considered significant. Results: Intraobserver reliability was excellent for radiographic DRR-IMA (0.95) and 3D coordinates assessment (0.99). Intermethod correlation between the three different imaging modalities (DDR, 2D and 3D), considering bias and interactions, were respectively 0.71 and 0.51 in control and HV patients. IMA measurements were found to be similar when measured in DRR, 2D and 3D WBCT images, for both controls and HV patients. Mean values and confidence intervals (CI) for controls were 8.8 degrees (CI, 7.9-9.7) in DDR images, 9.8 degrees (CI, 8.7-10.9) in 2D images and 10.6 degrees (CI, 9.5-11.8) in 3D images. When compared to controls, HV patients demonstraded significantly increased IMA (p&lt;0.05): 13.06 degrees (CI, 11.8-14.3) in DDR images, 12.1 degrees (CI, 10.8-13.3) in 2D images and 13.3 degrees (CI, 12.3-14.3) in 3D images. Conclusion: We found that similar values for IMA were measured in 2D reconstructed radiographs, WBCT 3D and 2D projected images. When compared to controls, HV patients were found to have increased IMA in all three different imaging types used (DDR, 2D and 3D). Intermethod correlation was higher for IMA performed in controls. Intraobserver reliability was excellent for both radiographic IMA measurements and WBCT 3D coordinates. Our study is the first study to evaluate measurements of the 3D-IMA in HV and control patients. Further investigations are required before guidelines for its clinical use can be formulated.

Foot Width Changes Following Hallux Valgus Surgery

Category: Midfoot/Forefoot Introduction/Purpose: Hallux valgus is one of the most common deformities of the adult foot, and can adversely affect quality of life, with common complaints including pain, footwear restrictions and cosmesis. Every clinician is familiar with the patients’ concerns regarding the postoperative foot appearance and footwear anticipations. Surprisingly, although patients are concerned with postoperative foot width, there are only scarce reports on this issue. This study was undertaken to evaluate the impact of hallux valgus surgical treatment on foot width. Methods: Study included 71 consecutive cases with moderate to severe hallux valgus treated with Scarf osteotomy, distal soft tissue release and Akin osteotomy as needed. Patients were included only if pre- and postoperative weightbearing X-rays at minimum 6 months followup were available. The average age was 55.7 years (range, 20 to 76), with average follow-up of 20.7 months (range, 6 to 96). Patients’ medical records were reviewed for clinical data, surgical technique and radiographic measurements. The radiographic measurements included hallux valgus angle (HVA), intermetatarsal angle (IMA), distal metatarsal articular angle (DMAA), and foot width. Foot width was assessed by measuring both the bony width (BW: maximal distance between the medial cortex of 1st metatarsal head and lateral cortex of the 5th metatarsal head) and the soft tissue width (STW: maximal distance between most medial soft tissue outline and the most lateral soft tissue outline at the level of metatarsal heads). Results: Preoperative HV deformity (mean HVA 35.8, IMA 14.1 and DMAA 15.2) was successfully corrected (postoperative mean HVA 13.7, IMA 6.9 and DMAA 7.7). Overall bony foot width was reduced by 5% and soft tissue foot width by 2% postoperatively. Further analysis showed there were 13 feet (18.3%) with increased (&gt;5%) bone width, 26 feet (36.6%) with no change (±5%) and 32 feet (45.1%) for which width decreased in more than 5% postoperatively. Patients with the widest foot before surgery, had a decrease in foot width following surgery whereas, patients with the narrowest foot width, had an increase in foot width. Magnitude of preoperative deformity (as assessed by HVA, IMA and DMMA measurements) or amount of correction had low correlation (&lt;0.2) with postoperative foot width. Conclusion: While the ability of surgery to correct HV deformity is well established and reported in the literature, its effect on foot width is less understood or predictable. Overall, the postoperative reduction of foot with was modest. Furthermore, while postoperative foot width (both bony and soft tissue) decreases or does not change in 4 out of 5 patients, there are cases in which foot width actually increases.

Interobeserver and Intraobserver Reproducibility of Hallux Valgus Angular Measurements and the Study of a Linear Measurement

The intermetatarsal angle (IMA), the hallux valgus angle (HVA), and the lateral sesamoid malalignment in relation to the first metatarsal are among the most commonly employed parameters to estimate the severity of the deformity. The aim of this study was to compare HV angular measurements and a linear measurement among 4 observers to determine its intraobserver and interobserver reliability, to find out whether this linear measurement technique is more reproducible than those already-described angular measurements. The IMA, the HVA, and the distance between the lateral cortex of the first metatarsal and the lateral cortex of the lateral sesamoid bone were measured from 50 standing, nonoperated hallux valgus feet. Radiographs were shuffled and reforwarded to the observers at a minimum interval of 30 days for a new measurement. When considering 2° of difference as significant, IMA and HVA measurements were not precise, showing low reproducibility for both intraobserver and interobserver assessment. Regarding the distance between the first metatarsal lateral cortex and the lateral sesamoid lateral cortex, when considering differences greater than 2 mm as significant, we observed higher precision and higher reproducibility. Angular measurements of hallux valgus deformity in anteroposterior standing radiographs that are manually performed with a goniometer are not precise and have low reproducibility. The linear measurement of the distance between the lateral cortices of the first metatarsal head and the lateral sesamoid demonstrated higher precision and higher reproducibility, and may be a cheap form to assess the correct indication of a distal osteotomy. Diagnostic, Level II.

Treatment of moderate Hallux valgus with a mini TightRope ® system: A modified technique

Objective To evaluate the clinical and radiological results in the treatment of moderate Hallux valgus with a minimally invasive system: Mini Tightrope ® (MTR). Material and methods We selected 32 patients, 36 feet (4 bilateral), with moderate Hallux valgus according to the criteria of Mann and Coughlin, and performed the Mini Tightrope ® modified technique. The American Orthopaedic Foot and Ankle Society (AOFAS) scale, the measurement of intermetatarsal angle (IMA) and metatarsophalangeal (MTT-F), sesamoid position, first toe mobility and the level of satisfaction, were assessed in these patients. Results A mean score of 88.0 points was obtained on the AOFAS scale (47.7 preoperative) after 24 months. In the last visit the radiographic correction of the IMA and the AH was 4.8° and 10.0° on average, respectively. There were 6 complications during follow-up (16%), 2 of which led to the patient being reoperated. Discussion and conclusions The Mini Tightrope ® is a reproducible technique that allows the treatment of moderate Hallux valgus. It achieves the same correction as osteotomies but preserving and avoiding the complications arising from those, being similar to less invasive percutaneous techniques. However, it is not without complications, some of them specific to this technique, which need to be determined.

Tratamiento del Hallux valgus moderado con sistema mini TightRope ®: técnica modificada

Objective To evaluate the clinical and radiological results in the treatment of moderate Hallux valgus with a minimally invasive system: Mini Tightrope ® (MTR). Material and methods We selected 32 patients, 36 feet (4 bilateral), with moderate Hallux valgus according to the criteria of Mann and Coughlin, and performed the Mini Tightrope ® modified technique. The American Orthopaedic Foot and Ankle Society (AOFAS) scale, the measurement of intermetatarsal angle (IMA) and metatarsophalangeal (MTT-F), sesamoid position, first toe mobility and the level of satisfaction, were assessed in these patients. Results A mean score of 88.0 points was obtained on the AOFAS scale (47.7 preoperative) after 24 months. In the last visit the radiographic correction of the IMA and the AH was 4.8° and 10.0° on average, respectively. There were 6 complications during follow-up (16%), 2 of which led to the patient being reoperated. Discussion and conclusions The Mini Tightrope ® is a reproducible technique that allows the treatment of moderate Hallux valgus. It achieves the same correction as osteotomies but preserving and avoiding the complications arising from those, being similar to less invasive percutaneous techniques. However, it is not without complications, some of them specific to this technique, which need to be determined.

A geometric analysis of hallux valgus: correlation with clinical assessment of severity

BackgroundApplication of plane geometry to the study of bunion deformity may represent an interesting and novel approach in the research field of hallux valgus. For the purpose of contributing to development of a different perspective in the assessment of hallux valgus, this study was conducted with three objectives: a) to determine the position on the intersection point of the perpendicular bisectors of the longitudinal axes of the first metatarsal and proximal phalanx (IP), b) to correlate the location of this point with hallux valgus deformity according to angular measurements and according to visual assessment of the severity carried out by three independent observers, and c) to assess whether this IP correlated with the radius of the first metatarsophalangeal arc circumference.MethodsMeasurements evaluated were intermetatarsal angle (IMA), hallux valgus angle (HVA), and proximal phalangeal articular angle (PPAA). The Autocad® program computed the location of the IP inside or outside of the foot. Three independent observers rated the severity of hallux valgus in photographs using a 100-mm visual analogue scale (VAS).ResultsMeasurements of all angles except PPAA showed significantly lower values when the IP was located out of the foot more distantly and vice versa, significantly higher values for severe deformities in which the IP was found inside the foot (p < 0.001). The IP correlated significantly with VAS scores and with the length of the radius of the circle that included the first metatarsophalangeal arc circumference (p < 0.001)ConclusionThe IP is a useful indicator of hallux valgus deformity because correlated significantly with IMA and HVA measurements, VAS scores obtained by visual inspection of the degree of deformity, and location of the center of the first metatarsophalangeal arc circumference.

Radiographic Angles in Hallux Valgus: Differences Between Measurements Made Manually and With a Computerized Program

The objective of this study was to compare angular measurements in the evaluation of hallux valgus deformities using a goniometer and a computerized program to assess degree of concordance between the two methods and determine the reliability of manual measurements. Angles measured included the hallux valgus angle (HVA), the intermetatarsal angle (IMA), the distal metatarsal articular angle (DMAA), and the proximal phalangeal articular angle (PPAA), also called the hallux valgus interphalangeus angle or interphalangeal angle. Measurements were made on preoperative weightbearing radiographs in 176 patients with symptomatic hallux valgus. Manual measurements were made with a goniometer by an orthopaedic surgeon. An independent experienced technician used digitized images to perform angular measurements with the Autocad software program (Autodesk Inc., San Rafael, CA). HVA values obtained with the two techniques were similar. However, significantly higher mean values were obtained with the Autocad for the IMA and PPAA measurements, and higher mean values were obtained for the DMAA measurement with the manual technique. Whereas differences were more or less randomly distributed for the HVA, in the remaining patients, measurements were clearly related to the measurement technique, i.e., for the DMAA, the manual technique had a tendency to show higher values, and for the IMA and PPAA the manual technique showed lower values than the computer. Correlations between both techniques for the different angular measurements were as follows: HVA, -0.179 (p = 0.018); DMMA, -0.294 (p < 0.001); PPAA, -0.876 (p < 0.001); and IMA, -0.661 (p < 0.001). The intraclass correlation coefficient (ICC) showed that the concordance between manual and Autocad angular measurements was excellent for the HVA (ICC = 0.89) and DMAA (ICC = 0.80) and very poor for the PPAA (ICC = 0.11) and IMA (ICC = 0.42). Angular measurements made on weightbearing radiographs with the Autocad in patients with hallux valgus deformities were more reliable than those made with a goniometer. Although for large angles, such as HVA and DMAA, results obtained with both measurement techniques were similar. Manual measurements, however, may underestimate the true values of the smaller IMA and PPAA angles.

Radiographic pre-operative assessment in hallux valgus: is it reliable?

Objective: The aim of this study was to assess the inter- and intra-observer reliability of the measurement of intermetatarsal angle (IMA), hallux valgus angle (HVA) and the diagnosis of joint congruency of the first metatarsophalangeal (MTP) joint. Method: Five observers assessed 50 pre-operative standing foot radiographs on two occasions. Five published methods of measuring IMA and HVA were used. Also the first MTP joint congruency was assessed. Results: The mean IMA and HVA measurements varied between methods on both occasions ( P<0.0001). Analysis of variance showed both method and observer variations were significant for IMA, but not for HVA. Diagnosis of congruency showed good agreement ( k=0.608) over two occasions, although this did vary by observer. Conclusion: Overall, there was no particular advantage to any measuring method. The reliability of IMA and HVA measurements are poor whichever measuring method is used and this limits the effectiveness of these radiographic findings for operation selection in hallux valgus.