Instability of the First Ray and Hallux Valgus in Patients with Adult Acquired Flatfoot Deformity (AAFD)

Category: Bunion Introduction/Purpose: Longitudinal arch collapse and first ray instability represent landmarks for adult acquired flatfoot deformity (AAFD), and have been linked to the development and progression of hallux valgus (HV). Radiographic evaluation of first ray instability is usually marked by increased angulation between the first and second metatarsals. The 1-2 intermetatarsal angle (IMA) is also an important aspect in the staging of HV deformity. Weightbearing CT imaging (WBCT) provides three-dimensional evaluation of dynamic deformities such as AAFD and HV. The purpose of this study was to assess the correlation between hallux valgus severity and foot collapse indicators using WBCT measurements, in patients with AAFD. We hypothesized that a flattening of the longitudinal arch, increased hindfoot valgus and forefoot abduction would correlate with greater IMA and HV angles. Methods: In this retrospective comparative study, 108 patients with stage II AAFD, 36 men and 72 women, with a mean age of 54.4 (range, 20-78) years, had their WBCTs evaluated by 2 blinded and independent board-certified foot and ankle orthopedic surgeons. The readers assessed multiple variables related to the severity of the hallux valgus and flatfoot deformities including: 1-2 intermetarsal angle, hallux valgus angle, talocalcaneal angle in the axial plane, talus-first metatarsal angle in the axial and sagittal planes, hindfoot alignment angle, hindfoot moment arm, navicular- and medial cuneiform-floor distance and the talonavicular uncoverage angle. Intra- and interobserver reliability were calculated by Pearson or Spearman’s correlation and intraclass correlation coefficient, respectively. A multiple regression analysis was used to evaluate the correlation between the variables indicative of AAFD and the severity of HV. P-values less than 0.05 were considered significant. Results: The intra- and interobserver reliability ranged from (0.65-0.99). Means and standard deviations for IM and HV angles were 11.3°±3.7° and 17.6°±13.4°, respectively. These angles significantly correlated with each other (p<0.0001). Most of the AAFD measurements evaluated were significantly associated with either increased IM or HV angles. IM angle correlated with increased talocalcaneal (26.0°±10.3°, p<0.0001), talus-first metatarsal (19.0°±13.6°, p=0.0001), and hindfoot alignment angles (22.3°±12.9°, p= 0.0049). HV angle correlated with medial cuneiform-floor distance (15.1mm±5.5 mm, p=0.0183), talus-first metatarsal angle in the axial plane (p=0.0004) and sagittal plane (15.7°±8.8°, p=0.0351), talonavicular uncoverage angle (17.8°±13.9°, p=0.0035). Hindfoot moment arm and navicular-floor distance were the only AAFD measurements that did not correlate with IM or HV angles. Conclusion: To the best of our knowledge this is the first study to confirm the association between AAFD, first ray instability and hallux valgus deformity using WBCT images. Our study results demonstrated that stage II flatfoot patients indeed have increased intermetatarsal and hallux valgus angles. Measurements traditionally used for staging the severity of AAFD showed significant positive correlation with increased IM or HV angles. Even though cause and effect cannot be determined with certainty, foot and ankle surgeons should consider these findings during evaluation and surgical planning of patients with AAFD.

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First-Tarsometatarsal Joint Alignment After First-Metatarsophalangeal Joint Arthrodesis for Hallux Valgus

Foot & Ankle Orthopaedics ◽

10.1177/24730114211008514 ◽

2021 ◽

Vol 6 (2) ◽

pp. 247301142110085

Author(s):

Christopher Traynor ◽

James Jastifer

Keyword(s):

Hallux Valgus ◽

Case Series ◽

Metatarsophalangeal Joint ◽

Retrospective Case ◽

Level Of Evidence ◽

First Metatarsophalangeal Joint ◽

First Metatarsal ◽

Metatarsal Angle ◽

Medial Cuneiform ◽

Radiographic Alignment

Background: Instability of the first-tarsometatarsal (TMT) joint has been proposed as a cause of hallux valgus. Although there is literature demonstrating how first-TMT arthrodesis affects hallux valgus, there is little published on how correction of hallux valgus affects the first-TMT joint alignment. The purpose of this study was to determine if correction of hallux valgus impacts the first-TMT alignment and congruency. Improvement in alignment would provide evidence that hallux valgus contributes to first-TMT instability. Our hypothesis was that correcting hallux valgus angle (HVA) would have no effect on the first-TMT alignment and congruency. Methods: Radiographs of patients who underwent first-MTP joint arthrodesis for hallux valgus were retrospectively reviewed. The HVA, 1-2 intermetatarsal angle (IMA), first metatarsal–medial cuneiform angle (1MCA), medial cuneiform–first metatarsal angle (MC1A), relative cuneiform slope (RCS), and distal medial cuneiform angle (DMCA) were measured and recorded for all patients preoperatively and postoperatively. Results: Of the 76 feet that met inclusion criteria, radiographic improvements were noted in HVA (23.6 degrees, P < .0001), 1-2 IMA (6.2 degrees, P < .0001), 1MCA (6.4 degrees, P < .0001), MC1A (6.5 degrees, P < .0001), and RCS (3.3 degrees, P = .001) comparing preoperative and postoperative radiographs. There was no difference noted with DMCA measurements (0.5 degrees, P = .53). Conclusion: Our findings indicate that the radiographic alignment and subluxation of the first-TMT joint will reduce with isolated treatment of the first-MTP joint. Evidence suggests that change in the HVA can affect radiographic alignment and subluxation of the first-TMT joint. Level of Evidence: Level IV, retrospective case series.

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Structural Effect of Long-Term Use of Medial Arch Support Insole on Children with Pediatric Flexible Flatfoot

Foot & Ankle Orthopaedics ◽

10.1177/2473011419s00143 ◽

2019 ◽

Vol 4 (4) ◽

pp. 2473011419S0014

Author(s):

Jun Young Choi ◽

Min Jin Kim ◽

Jin Soo Suh

Keyword(s):

Structural Effect ◽

Hindfoot Alignment ◽

First Metatarsal ◽

Metatarsal Angle ◽

Medial Cuneiform ◽

Flexible Flatfoot ◽

Arch Support ◽

Group 2 ◽

Physeal Closure ◽

Group 1

Category: Midfoot/Forefoot Introduction/Purpose: This prospective study aimed to rule out the effect of the normal physiologic maturation in applying medial arch support insole for patients with pediatric flexible flatfoot (PFFF). Methods: From January 2005 to June 2015, 18 patients (34 feet) in group 1 (insole was continuously applied) and 16 patients (32 feet) in group 2 (untreated group) were enrolled. A medial arch support insole was applied from age 10-11 years until radiographic physeal closure. Results: In group 1, the talonavicular coverage angle, lateral talo-first metatarsal angle, calcaneal pitch angle, and medial cuneiform height were significantly changed at final follow-up, although all values were still within the abnormal range. Moreover, no significant differences were found in any of the increments of the radiographic parameters between groups 1 and 2. Conclusion: Radiographic improvements were found in both medial arch support insole-treated and untreated groups even if all radiographic values were still within the abnormal range. This means that PFFF could be somehow improved with heel stretching exercise until the physes were closed. Further, hindfoot alignment remained unchanged regardless of the medial arch support insole application.

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Clinical and Radiological Evaluation of Results of Surgical Correction of Forefoot Adduction by Cuneiform and Cuboid Osteotomy Using Radiological Forefoot Measurements

Ortopedia Traumatologia Rehabilitacja ◽

10.5604/01.3001.0014.4226 ◽

2020 ◽

Vol 22 (5) ◽

pp. 263-272

Author(s):

Barbara Jasiewicz ◽

Tomasz Potaczek ◽

Sławomir Duda ◽

Jakub Adamczyk ◽

Jacek Lorkowski

Keyword(s):

First Metatarsal ◽

Radiologic Evaluation ◽

Care Givers ◽

Metatarsal Angle ◽

Medial Cuneiform ◽

Age At Surgery ◽

First Ray ◽

Metatarsus Adductus ◽

The Mean

Background. Forefoot adduction is a relatively common problem. It is usually mild or it can be effectively managed conservatively. Severe deformities may require surgical treatment. The aim of the study was to perform a clinical and radiologic evaluation of forefoot adduction correction using medial cuboid and cuneiform osteotomy with a transposed wedge. Material and methods. This is a retrospective study involving 16 patients who underwent 20 procedures. Mean age at surgery was 6 years (3-13). Clinical evaluation was based on measurements of forefoot deviation and patients’/care-givers’ subjective opinion. The radiologic parameters assessed comprised the first ray angle, talar-first metatarsal angle, calcaneal-fifth metatarsal angle, talocalcaneal angle, metatarsus adductus angle, and Kilmartin’s angle. Results were then compared in children below and above 6 years of age. The mean duration of follow-up was 4.6 years (2-9). Results. The clinical and subjective outcome was rated as good in 16 procedures and satisfactory in 4. The talar-first metatarsal angle, calcaneal-fifth metatarsal angle, metatarsus adductus angle, and Kilmartin’s angle were significantly reduced, while the talocalcaneal and first ray angle remained unchanged. A significantly better correction of metatarsus adductus and talar-first metatarsal angle was achieved In children below 6 years of age compared to older patients. Conclusions. 1. Medial cuneiform and cuboid osteotomy with a transposed wedge improves both clinical and radiological parameters, especially in children under the age of 6. 2. Besides the metatarsus adductus angle, the talar-first metatarsal, calcaneal-fifth metatarsal and Kilmartin’s angles appear to be good radiologic indicators of correction.

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Comparison between Weight Bearing Radiographs and Weight Bearing ConeBeam CT Examinations in the Assessment of Adult Acquired Flatfoot Deformity

Foot & Ankle Orthopaedics ◽

10.1177/2473011417s000152 ◽

2017 ◽

Vol 2 (3) ◽

pp. 2473011417S0001

Author(s):

Cesar de Cesar Netto ◽

Lew Schon ◽

Apisan Chinanuvathana ◽

Francois Lintz ◽

Lucas Furtado Da Fonseca

Keyword(s):

Pearson Correlation ◽

Weight Bearing ◽

Three Dimensional ◽

Imaging Modalities ◽

Anatomical Landmarks ◽

First Metatarsal ◽

Metatarsal Angle ◽

Medial Cuneiform ◽

Adult Acquired Flatfoot Deformity ◽

Conebeam Ct

Category: Hindfoot Introduction/Purpose: Adult acquired flatfoot deformity (AAFD) represents a biomechanical derangement involving the three- dimensional (3D) midfoot and hindfoot osseous complex, and can be challenging to optimally characterize using conventional two- dimensional (2D) plain radiographs. Weightbearing (WB) ConeBeam CT (CBCT) can better demonstrate the deformity of the 3D structures during WB. Therefore, we compared validated AAFD measurements between WB conventional radiographs and WB CBCT images. Methods: In this prospective, IRB approved and HIPAA compliant study, 20 patients (20 feet, 15 right and 5 left) with clinical diagnosis of flexible AAFD were included, 12 males and 8 females, with a mean age of 52.2 years (range, 20 to 88 years of age), and average BMI of 30.35 kg/m2 (range, 19.00 to 46.09 kg/m2). Involved feet underwent standing (WB) anteroposterior (AP) and lateral radiographs, and were also scanned by WB CBCTs. Both imaging modalities were assessed with traditional AAFD measurements obtained at sagittal (lateral view on radiograph) and axial (anteroposterior view on radiograph) planes using predefined anatomical landmarks, by two independent and blinded foot and ankle fellowship-trained observers. Intra- and Inter- observer reliabilities for both imaging modalities were calculated using Pearson correlation. WB radiograph and WB CBCT measurements were compared by T-Test of the means. P- values < 0.05 were considered significant. Results: There was good to excellent intra and inter-observer agreements for most of the measurements on both radiographs and WB CBCT images, with slightly better results favoring WBCT measurements. When comparing WB radiographs and WB CBCT images, we found significant differences in the mean values for some of the measurements, including: talus-first metatarsal angle in the sagittal plane (11.34° x 21.73°, p<0.0001), navicular-medial cuneiform angle (13.19° x 7.63°, p<0.0004), medial cuneiform to floor distance (6.70 mm x 5.50 mm, p<0.0003) and navicular to floor distance (31.34 mm x 23.22 mm, p<0.0001). No significant differences were found when measuring: talus-first metatarsal angle in the axial plane, talar uncoverage angle, cuboid to floor distance and calcaneal inclination angle. Conclusion: Traditional adult acquired flatfoot deformity radiographic measurements are obtainable using high resolution 3D WB CBCT imaging. Measurements performed on WB CBCT have similar intra-observer and overall higher inter-observer reliability when compared to WB radiographs. The statistically significant differences found in some of the measurements, when comparing both imaging techniques, might be related to a better characterization of the three-dimensional deformity on WB CBCT images.

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Understanding the Rotational Positioning of the Bones in the Medial Column of the Foot: A Weightbearing CT Analysis

Foot & Ankle Orthopaedics ◽

10.1177/2473011420s00449 ◽

2020 ◽

Vol 5 (4) ◽

pp. 2473011420S0044

Author(s):

Thiago A. Silva ◽

Daniel Baumfeld ◽

Shuyuan Li ◽

Nacime S. Mansur ◽

Francois Lintz ◽

...

Keyword(s):

Hallux Valgus ◽

Proximal Phalanx ◽

Foot And Ankle ◽

First Metatarsophalangeal Joint ◽

First Metatarsal ◽

Rotational Position ◽

Medial Cuneiform ◽

Bone Segment ◽

Essential Components ◽

Weightbearing Ct

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Rotational deformities of the first ray have been described as essential components of hallux valgus (HV) deformity, influencing its severity and progression. The exact deformity location along the medial column, as well as the typical rotational pattern of each bone, is yet to be fully understood. The objective of this study was to evaluate the rotational position of the navicular, medial cuneiform, first metatarsal and proximal phalanx using three-dimensional weightbearing CT (WBCT) images of a diversity of patients with foot pathologies. Our goal was to describe the rotational profile of medial column bones, serving as a reference for future studies. Methods: A retrospective review of patients that underwent WBCT assessment of multiple foot and ankle pathologies was conducted in a single Institution. A blinded and independent Fellowship-Trained Foot and Ankle Orthopedic Surgeon performed measurements in Multiplanar Reconstruction (MPR) WBCT images assessing the rotational profile of each bone of the medial column (navicular, medial cuneiform, first metatarsal and proximal phalanx of the great toe), as demonstrated in the attached figure. The first metatarsal, representing a long bone, was evaluated on its proximal and distal ends. A total of 110 patients were included. As standard, we considered pronation as positive values and supination as negative values. Comparisons were performed using independent t-tests or Wilcoxon tests. P-values of <0.05 were considered significant. Results: The mean values and 95% Confidence Interval for the rotational profile of the medial column bones were found to be respectively: Navicular, pronated 43.2o (41.1 to 45.2); Medial Cuneiform, supinated -2.5o (-4.3 to -0.7); Proximal First Metatarsal, supinated -28.1o (-32 to -24.1); Distal Metatarsal, pronated 18.5o (16.3 to 20.7); First Toe Proximal Phalanx, pronated of 21.6o (18.7 to 24.5). Significant differences were found in the rotational position of each bone/segment (p<0.0001), with the exception of the distal metatarsal/proximal phalanx (p=0.11), that demonstrated similar amounts of pronation. When considering each segment/joint in isolation, the highest rotational deformity was found to exist within the first metatarsal (pronated 46.6o), naviculo-cuneiform joint (supinated 45.7o), first tarsometatarsal joint (supinated 25.5o) and first metatarsophalangeal joint (pronated 3.1 o). Conclusion: Our study described the rotational profile of the medial column bones using WBCT images, in a population of patients with diverse foot and ankle pathologies. We found significant differences in the rotational position of most of the bones along the medial column. The greatest amount of rotation was found to happen within the first metatarsal, which undergoes an average of 46o of pronation from proximal to distal, probably compensating a considerable amount of supination of the naviculo- cuneiform and first tarsometatarsal joints. Further studies comparing hallux valgus patients and controls are needed.

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Correlation Between Three-Dimensional Biometric Weightbearing CT Assessment of Hindfoot Alignment and Conventional Measurements of Adult Acquired Flatfoot

Foot & Ankle Orthopaedics ◽

10.1177/2473011420s00059 ◽

2020 ◽

Vol 5 (4) ◽

pp. 2473011420S0005

Author(s):

Nacime S. Mansur ◽

Cesar de Cesar Netto ◽

Katrina E. Bang ◽

Chris Cychosz ◽

Jonathan H. Garfinkel ◽

...

Keyword(s):

Ankle Joint ◽

Interobserver Reliability ◽

Three Dimensional ◽

Foot And Ankle ◽

Moment Arm ◽

Hindfoot Alignment ◽

Mean Values ◽

Horizontal Angle ◽

Retrospective Comparative Study ◽

Weightbearing Ct

Category: Hindfoot; Ankle; Other Introduction/Purpose: Semi-automatic three-dimensional (3D) biometric weightbearing CT (WBCT) tools have been shown to accurately demonstrate the relationship between the center of the ankle joint and the tripod of the foot. The measurement of the Foot and Ankle Offset (FAO) represents an optimized biomechanical assessment of foot alignment. The objective of this study was to evaluate the correlation between FAO and traditional adult acquired flatfoot deformity (AAFD) markers, measured in different planes. We hypothesized that the FAO would significantly correlate with other radiographic markers of pronounced AAFD. Methods: In this retrospective comparative study, we included 113 patients with stage II AAFD, 43 men and 70 women, mean age of 53.5 (range, 20 to 86) years. Three-dimensional coordinates (X, Y and Z planes) of the foot tripod (most plantar voxel of the first and fifth metatarsal heads, and calcaneal tuberosity) and the center of the ankle joint (most proximal and central voxel of the talar dome) were harvested by two blinded and independent fellowship-trained orthopedic foot and ankle surgeons. The FAO was automatically calculated using the 3D coordinates by dedicated software. Multiple WBCT parameters related to the severity of the deformity in the coronal, sagittal, and transverse plane were manually measured. Results: We found overall good to excellent intra (range, 0.84-0.99) and interobserver reliability (range, 0.71-0.96) for manual AAFD measurements. FAO semi-automatic measurements demonstrated excellent intra (0.99) and interobserver reliabilities (0.98). Hindfoot moment arm (p<0.00001), subtalar horizontal angle (p<0.00001), talonavicular uncoverage angle (p=0.00004) and forefoot arch angle (p=0.0001) were the only variables found to significantly influence and correlate with FAO measurements, with an R-squared value of 0.79. A value of hindfoot moment arm of 19.8mm was found to be a strong threshold predictor of increased values of FAO, with mean values of FAO of 6.5 when the HMA was lower than 19.8mm and 14.6 when the HMA was equal or higher than 19.8mm. Conclusion: We found that 3D WBCT semi-automatic measurements of Foot and Ankle Offset (FAO) significantly correlated with traditional markers of pronounced AAFD. HMA, subtalar horizontal angle, talonavicular uncoverage angle and forefoot arch angle were found to explain 79% of the variations in FAO measurements. FAO Measurements were also found to be more reliable than the manual measurements. The FAO offers a more complete biomechanical and multiplanar assessment of the AAFD, that that accounts for relative positioning of the foot tripod and the center of the ankle joint, representing in a single measurement the three-dimensional components of the deformity.

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Mobility of the First Ray in Various Foot Disorders

Foot & Ankle International ◽

10.3113/fai.2012.0044 ◽

2012 ◽

Vol 33 (1) ◽

pp. 44-49 ◽

Cited By ~ 18

Author(s):

Justin Greisberg ◽

Lisa Sperber ◽

Daniel E. Prince

Keyword(s):

Hallux Valgus ◽

Hallux Rigidus ◽

Stress Fractures ◽

Consecutive Series ◽

Foot And Ankle ◽

Level Of Evidence ◽

First Metatarsal ◽

Posterior Tibial ◽

First Ray ◽

Made In

Background: Instability of the first ray has been proposed by Morton and others to be a major cause of several foot disorders, including hallux valgus, transfer metatarsalgia, lesser metatarsal stress fractures, and second metatarsophalangeal diseases. However, there are few studies to support these theories. In this study, we have used a simple device to measure first ray elevation and translation in a consecutive series of foot and ankle patients. We propose that mobility of the first ray will be increased in patients with hallux valgus, metatarsalgia, hallux rigidus, lesser metatarsal stress fractures, posterior tibial tendinitis, and interdigital neuromas. Methods: Measurements of first ray translation and elevation were made in 345 feet in 315 patients. One or more pathologic diagnoses were recorded for each foot, and data was analyzed by a statistician. Results: First ray mobility was increased in females compared to males. Patients with hallux valgus and metatarsalgia had greater mobility than other patients. Those feet with low arches showed greater mobility than those with high arches. Patients with hallux rigidus showed decreased mobility. We failed to find any differences for patients with stress fractures, posterior tibial tendinitis, or neuromas, but some of these groups may have had insufficient power. Conclusion: First ray translation and elevation are two different measures of medial column instability. Although they are distinct measures, they closely paralleled each other in this series. An association was found between increased first metatarsal elevation and several foot disorders. Although such an association does not prove causation, and it is likely other factors may play a role in many patients, this data does link instability of the first ray to some diseases. The decreased mobility seen in patients with hallux rigidus may offer new insights into the etiology of that disorder. Level of Evidence: III, Comparative Study

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Radiographic Assessment of Foot Alignment in Juvenile Hallux Valgus and Its Relationship to Flatfoot

Foot & Ankle International ◽

10.1177/1071100719850148 ◽

2019 ◽

Vol 40 (9) ◽

pp. 1079-1086

Author(s):

Hyun Woo Kim ◽

Kun Bo Park ◽

Yoon Hae Kwak ◽

Seokhwan Jin ◽

Hoon Park

Keyword(s):

Hallux Valgus ◽

Weight Bearing ◽

Hallux Valgus Angle ◽

Hindfoot Alignment ◽

First Metatarsal ◽

Metatarsal Angle ◽

Valgus Angle ◽

Significant Difference ◽

Metatarsus Adductus ◽

Foot Alignment

Background: The relationship between juvenile hallux valgus (JHV) and flatfoot has not been clearly established. The aim of this study was to assess radiographic measurements in feet with JHV compared with matched controls and to investigate whether the foot alignment of JHV is related to flatfoot. Methods: We retrospectively reviewed 163 patients with JHV as defined as hallux valgus angle greater than 20 degrees and intermetatarsal greater than angle than 10 degrees. Patients with open physes of the feet and who had weight-bearing radiographs of the feet were included. Another 55 normal participants served as controls. Patients with JHV were divided into 2 subgroups: Group 1 included patients with asymptomatic JHV and group 2 consisted of those treated with correctional surgery for painful JHV. Twelve radiographic indices were analyzed, including calcaneal pitch angle, tibiocalcaneal angle, talocalcaneal angle, naviculocuboid overlap, talonavicular coverage angle, lateral talo–first metatarsal angle, anteroposterior talo–first metatarsal angle, metatarsus adductus angle, hallux valgus angle, intermetatarsal angle, distal metatarsal articular angle, and first metatarsal cuneiform angle. The groups were compared by age, gender, and the above radiographic parameters. Results: There was no significant difference in hindfoot alignment of patients with JHV and controls. Naviculocuboid overlap ( P <.001), lateral talo–first metatarsal angle ( P = .002), and metatarsus adductus angle ( P = .004) were significantly greater in patients with JHV than in controls, whereas the anteroposterior talo–first metatarsal angle ( P = .026) was significantly less. Symptomatic and asymptomatic JHV patient subsets showed no significant radiologic differences. Conclusion: Radiographic profiles in patients with JHV were inconsistent with regard to features of flatfoot, and foot alignment was unrelated to the presence of symptoms or degree of deformity in JHV. Level of Evidence: Level III, retrospective comparative series.

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Mobility Changes in the First TMT Joint after Proximal First Metatarsal Osteotomy for Hallux Valgus Evaluated by Weightbearing CT and a 3D Analysis System

Foot & Ankle Orthopaedics ◽

10.1177/2473011417s000244 ◽

2017 ◽

Vol 2 (3) ◽

pp. 2473011417S0002

Author(s):

Tadashi Kimura ◽

Makoto Kubota ◽

Hidekazu Hattori ◽

Kazuhiko Minagawa ◽

Naoki Suzuki ◽

...

Keyword(s):

Hallux Valgus ◽

Three Dimensional ◽

Metatarsal Osteotomy ◽

First Metatarsal ◽

Valgus Angle ◽

Medial Cuneiform ◽

First Ray ◽

The Mean ◽

Weightbearing Ct

Category: Bunion Introduction/Purpose: In a previous study, we found that feet with hallux valgus show significantly greater three-dimensional mobility than normal feet in all joints of the first ray. Displacement was particularly pronounced in the first TMT joints, indicating that this is the primary cause of first ray hypermobility. We developed a plate used specifically for proximal first metatarsal osteotomy to perform three-dimensional correction of hallux valgus and associated deformities. In this study, we evaluated changes in mobility of the first TMT joints after surgery in 3D using weightbearing CT. Methods: The subjects were 5 feet of 5 female patients with hallux valgus (mean age 56 years, mean hallux valgus angle 38°). We performed non-weightbearing and weightbearing (using a load equivalent to body weight) CT scans before surgery using an original loading device (Fig a). We reconstructed 3D models from captured images by segmentation and defined axial coordinate system (Fig b). Next, we measured the three-dimensional displacement of the first metatarsal bone relative to the medial cuneiform bone under weightbearing conditions. At 1 to 1.5 years after proximal metatarsal osteotomy for all patients, we performed a follow-up CT scans using the same method and compared preoperative and postoperative displacement. Student’s t- test was performed to statistically compare data and statistical significance was set at p < 0.05. Results: Postoperatively (when performing a follow up CT), the mean hallux valgus angle improved from 38° to 10° and the mean first-second metatarsal angle improved from 23° to 7°. The mean score on the Japanese Society for Surgery of the Foot hallux scale improved from 62 points to 97 points. Displacement of the first metatarsal bone relative to the medial cuneiform bone between non-weightbearing and weightbearing conditions decreased significantly in all directions, from 4.2° ± 1.8° to 1.6° ± 1.1° of dorsiflexion (p = 0.02), 4.9° ± 1.8° to 0.7° ± 0.9° of inversion (p = 0.001), and 4.4° ± 1.9° to 1.7° ± 0.8° of adduction (p = 0.01). Conclusion: Displacement of the first TMT joints under weightbearing conditions decreased after our surgery. This indicates that the surgery corrected hallux valgus and associated pes planus and produced favorable functional outcomes by improving the shape of the foot and hypermobility of the first ray through correction of the orientation and tension of surrounding tendons and ligaments and the plantar aponeurosis. In the future, we plan to further examine the pathology and treatment of hallux valgus with a focus on postoperative changes in soft tissue orientation.

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The Assessment of First Metatarsal Rotation in the Normal Adult Population Using Weightbearing Computed Tomography

Foot & Ankle International ◽

10.1177/10711007211015187 ◽

2021 ◽

pp. 107110072110151

Author(s):

Ali-Asgar Najefi ◽

Amit Zaveri ◽

Mohammad Khalid Alsafi ◽

Karan Malhotra ◽

Shelain Patel ◽

...

Keyword(s):

Computed Tomography ◽

Hallux Valgus ◽

Normal Population ◽

Intraclass Correlation ◽

Normal Range ◽

Hindfoot Alignment ◽

First Metatarsal ◽

Small Series ◽

Metatarsal Angle ◽

Α Angle

Background: The importance of the rotational profile of the first metatarsal is increasingly recognized in the surgical planning of hallux valgus. However, rotation in the normal population has only been measured in small series. We aimed to identify the normal range of first metatarsal rotation in a large series using weightbearing computed tomography (WBCT). Methods: WBCT scans were retrospectively analyzed for 182 normal feet (91 patients). Hallux valgus angle, intermetatarsal angle, anteroposterior/lateral talus–first metatarsal angle, calcaneal pitch, and hindfoot alignment angle were measured using digitally reconstructed radiographs. Patients with abnormal values for any of these measures and those with concomitant pathology, previous surgery, or hallux rigidus were excluded. Final assessment was performed on 126 feet. Metatarsal pronation (MPA) and α angles were measured on standardized coronal computed tomography slices. Pronation was recorded as positive. Intraobserver and interobserver reliability were assessed using intraclass correlation coefficients (ICCs). Results: Mean MPA was 5.5 ± 5.1 (range, –6 to 25) degrees, and mean α angle was 6.9 ± 5.5 (range, –5 to 22) degrees. When considering the normal range as within 2 standard deviations of the mean, the normal range identified was −5 to 16 degrees for MPA and −4 to 18 degrees for α angle. Interobserver and intraobserver reliability were excellent for both MPA (ICC = 0.80 and 0.97, respectively) and α angle (ICC = 0.83 and 0.95, respectively). There was a moderate positive correlation between MPA and α angle (Pearson coefficient 0.68, P < .001). Conclusion: Metatarsal rotation is variable in normal feet. Normal MPA can be defined as less than 16 degrees, and normal α angle can be defined as less than 18 degrees. Both MPA and α angle are reproducible methods for assessing rotation. Further work is needed to evaluate these angles in patients with deformity and to determine their significance when planning surgical correction of hallux valgus. Level of Evidence: Level III, retrospective comparative study.

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