Comparison of Tibial Sesamoid Position on Anteroposterior and Axial Radiographs Before and After Triplane Tarsal Metatarsal Joint Arthrodesis

We reviewed the radiographic results of a group of patients who had undergone triplane correctional tarsometatarsal arthrodesis for symptomatic hallux abducto valgus with metatarsus primus abducto valgus. Of the 21 feet included in the present review, 17 (81%) displayed radiographic findings of metatarsal pronation preoperatively based on axial sesamoid views and positive lateral round sign on anteroposterior radiographs. At a mean follow-up period of 5.2 ± 1.6 months, a significant improvement in the tibial sesamoid position (TSP) on both anteroposterior (AP) and axial radiographs was measured. A negative metatarsal round sign, indicating correction of coronal plane metatarsal rotation, was observed in 20 of the 21 feet (95.2%) on AP radiographic evaluation. All 21 patients (100%) had obtained resolution of sesamoid subluxation on the sesamoid axial view at the final follow-up examination. The sesamoid axial position was consistently normal when the round sign was absent, and the TSP was in the normal range of 1 to 3 on the AP radiograph. Sesamoid subluxation from the normal position with the tibial sesamoid on or lateral to the crista was noted in 4 feet (19%) preoperatively and 0 feet postoperatively. This confirmed that lateral round sign of the first metatarsal head and a high TSP noted on the AP radiograph are both related to metatarsal pronation and can be corrected concurrently with coronal plane varus rotation of the first metatarsal as a part of the procedure.     

Relationship of Frontal Plane Rotation of First Metatarsal to Proximal Articular Set Angle and Hallux Alignment in Patients Undergoing Tarsometatarsal Arthrodesis for Hallux Abducto Valgus: A Case Series and Critical Review of the Literature

Rotation of the first metatarsal, as a component of hallux abducto valgus, is rarely discussed and is not addressed as a component of most hallux valgus corrective procedures. We believe frontal plane rotation of the first metatarsal to be an integral component of hallux abducto valgus deformity (the “third plane of deformity”) and believe de-rotation is necessary for complete deformity correction. We observed the change in angular measurements commonly used in the evaluation of hallux valgus deformity in patients who underwent a modified lapidus procedure. We measured the intermetatarsal angle, hallux abductus angle, proximal articular set angle, and tibial sesamoid position on weightbearing radiographs of 25 feet in 24 patients who had undergone tarsal metatarsal corrective arthrodesis and lateral capsular release. Specific attention was given to reduction of the frontal plane rotation of the first metatarsal during correction. Our results showed a change in the angular measurements observed by 4 investigators as follows. The mean change in the intermetatarsal angle was 10.1° (p < .0001). The mean change in the hallux abductus angle was 17.8° (p < .0001). The mean change in the proximal articular set angle was 18.7° (p < .0001). The mean change in the tibial sesamoid position was 3.8 (p < .0001). Also, a consistent valgus, or everted position of the first metatarsal, was noted as a component of the hallux abducto valgus deformity in our patient population and was corrected by varus rotation or inversion of the metatarsal. We also reviewed the current literature related to anatomic changes in the first ray in the patient with hallux valgus deformity and reviewed our hypothesis regarding the reduction in the proximal articular set angle, which we believe to be related to frontal plane rotation of the first metatarsal, resulting in a radiographic artifact.     

First Tarsometatarsal Joint Derotational Arthrodesis—A New Operative Technique for Flexible Hallux Valgus without Touching the First Metatarsophalangeal Joint

No operative technique for hallux valgus has been introduced in which the first metatarsophalangeal joint is not touched. We report the first tarsometatarsal joint derotational arthrodesis in which we mimic the function of the peroneus longus tendon without involving the first metatarsophalangeal joint, allowing function of the windlass mechanism without interference. We treated 66 patients (62 women and 4 men) with 84 flexible hallux valgus feet using our new operative technique. Preoperative and postoperative follow-up weightbearing radiographs were evaluated. Most patients had a pronation type foot (78%) preoperatively, and mean correction in hallux valgus and intermetatarsal angle was 20° and 9°, respectively (p < .001). The LaPorta classification showed a median change of 2.5 U (p < .001). We have described a new operative technique for flexible hallux valgus. The first tarsometatarsal joint derotational arthrodesis showed notable correction angles in hallux valgus, although the first metatarsophalangeal joint was left intact.     

Observed Changes in Radiographic Measurements of the First Ray after Frontal Plane Rotation of the First Metatarsal in a Cadaveric Foot Model

We observed the changes in the angular measurements commonly used in the evaluation of the first metatarsal and first metatarsophalangeal joint in cadaveric specimens before and after frontal plane rotation of the first metatarsal. Measurements of the first and second intermetatarsal angle (IMA), hallux abductus angle, proximal articular set angle, and tibial sesamoid position (TSP) were taken after varying degrees of varus and valgus rotation of the first metatarsal. Standard dorsoplantar radiographs were taken at 0°, 10°, 20°, and 30° of valgus rotation of the first metatarsal and repeated at 10°, 20°, and 30° varus rotation of the first metatarsal. The data were analyzed using a mixed linear model to compare the change in each angle measurement over the range of valgus and varus rotation. The change in the TSP was significant in both valgus and varus rotations (p = .0004 and p = .028, respectively), an increase in valgus rotation causing an increase in the TSP and an increase in varus rotation causing a decrease in TSP. The change in the IMA was significant compared with valgus rotation (p = .028), showing that as the valgus rotation increased, the IMA also increased. However, compared with the varus rotation, the correlation was not significant (p = .18). The proximal articular set angle and hallux abductus angle measurements, compared with metatarsal rotation, showed positive trends but were not statistically significant. From our results and a review of the published data, we have hypothesized that frontal plane rotation of the first metatarsal is an integral component of hallux abducto valgus pathologic features, specifically in relation to the TSP and IMA.     

Relationship Between Plantar Callosity and Foot Deformity in Hallux Valgus Using Weightbearing Computed Tomography

Plantar callosities under lesser metatarsals are often accompanied by the hallux valgus, and the cause of callosity is thought to be associated with the foot deformity, such as the metatarsal length discrepancy, the abnormal metatarsal head height, cavus, flat foot, and rheumatoid conditions. However, it is unclear which variable is most involved in the cause of callosity in hallux valgus deformity. To clarify the factors associated with the callosity with hallux valgus deformity, we conducted multiple image assessments based on weightbearing radiography and computed tomography. A retrospective review was performed based on the collection of clinical records from all patients with hallux valgus treated from 2010 to 2019 in our institution. We measured the hallux valgus angle, intermetatarsal angles, calcaneal pitch angles, talo-first metatarsal angles, metatarsal length, metatarsal head height, first metatarsal pronation angles, and sesamoid position with weightbearing radiography and computed tomography. We analyzed the relation between callosity formation and imaging assessments using univariate and multivariate logistic regression models. Fifty feet were retrospectively evaluated, and multiple logistic analyses by the stepwise method revealed that the first metatarsal-lateral-sesamoid distance was the only radiographical variable associated with callosity formation among all the tested variables (p < .001). As the grade of the callosity became more severe, the lateral shift of the lateral sesamoid increased. The position of the sesamoid bone appears to have a critical role in the assessment and choice of treatment protocols and further research needs to be conducted on the relationship with the position of sesamoid bone to elucidate the mechanism of callus formation.     

Degenerative osteoarthrosis of tarsometatarsal joints in hallux valgus: a radiographic study

To clarify the pathogenesis of degenerative osteoarthrosis of the tarsometatarsal joints in hallux valgus, we evaluated dorsoplantar and lateral radiographs during weight-bearing in 16 patients (25 feet) with hallux valgus accompanied by degenerative osteoarthrosis of the tarsometatarsal joints and 25 controls (25 feet) with hallux valgus alone. The proximal second metatarsal articular angle (a parameter we devised), the hallux valgus angle, intermetatarsal angle, metatarsal length, sesamoid displacement, calcaneal pitch, and foot length were measured and then evaluation using a mapping system was performed. There were no significant differences in the hallux valgus angle, intermetatarsal angle, sesamoid displacement, calcaneal pitch, or foot length. In the presence of degenerative osteoarthrosis of the tarsometatarsal joints, the second, third, and fourth metatarsals were long, and a large inclination of the proximal articular surface of the second metatarsal and adduction of the first to fourth metatarsals were observed. These findings appeared to be involved in the development of this disorder.     

Comparison of Radiographic Measurements Before and After Triplane Tarsometatarsal Arthrodesis for Hallux Valgus

We present a comparison of preoperative and final postoperative first ray measurements in 109 feet after triplane tarsometatarsal arthrodesis at a mean follow-up time of 17.4 months. Preoperative and final postoperative first ray variables including intermetatarsal angle (IMA), hallux valgus angle (HVA), tibial sesamoid position (TSP), distal metatarsal articular angle (DMAA), Seiberg index, metatarsal rotation angle (MRA), sesamoid subluxation, osseous union, and hardware failure were evaluated. Measurements were made by consistently using the mid-diaphyseal line of the bone segments for both preoperative and postoperative assessments. The mean preoperative HVA, IMA, and TSP were 22.9°, 13.3°, and 4.6. The mean differences (95% confidence interval) in preoperative and postoperative values were –14.9° (–16.3° to –13.4°) for HVA, –7.7° (–8.2° to –7.2°) for IMA, and –2.6 (–2.8 to –2.3) for TSP. Among bunions with MRA measurements, the mean difference was –12.3° (–14.5° to –10.0°). The preoperative to postoperative DMAA decreased by a mean of –14.2° (–15.9° to –12.6°). The results of this study suggest that triplane tarsometatarsal arthrodesis produces appropriate correction of hallux valgus radiographic parameters.     

Does Hallux Valgus Exhibit a Deformity Inherent to the First Metatarsal Bone?

Hallux valgus is a common condition, and it still poses some challenges. The identification of factors associated with the development of the deformity is of paramount importance in obtaining a full correction of the disorder. Hallux pronation is one of the frequently found components, especially in larger deformities, but the cause and exact location of this condition are not fully understood. The aim of the present study was to investigate whether there is a rotational deformity inherent to the first metatarsal bone. A case-control study was conducted on patients with and without hallux valgus who were subjected to computed tomography with multiplanar reconstruction. Statistical analysis was performed by means of a mixed model adjusted for foot and gender to compare metatarsal rotation between cases and controls. Correlations between numerical quantitative measurements were investigated by means of Pearson's correlation coefficient obtained in a linear mixed model. A total of 82 feet (tests) were analyzed in the hallux valgus group and 64 feet (tests) in the control group (N = 146). The hallux valgus group was significantly different from the control group (p < .001). Mean metatarsal bone rotation was 15.36° (range 1.65° to 32.52°) in the hallux valgus group and 3.45° (range −7.40° to 15.56°) in the control group. The difference between the means was 11.9° (confidence interval 9.2° to 14.6°). In conclusion, patients with hallux valgus exhibited increased exclusive bone rotation of the first metatarsal toward pronation compared with the population without this condition.     

The Rotational Effect of Scarf Osteotomy With Transarticular Lateral Release on Hallux Valgus Correction

The purpose of this study was to explore the rotational effect of scarf osteotomy with transarticular lateral release (TALR) on hallux valgus correction. From January 2016 to January 2018, 28 consecutive patients (30 feet) were included in this study. The first intermetatarsal angle (IMA), hallux valgus angle (HVA), and round-shaped lateral edge of the first metatarsal head (R sign), and sesamoid rotation angle (SRA) were recorded prior to and 3 months after the surgery. The rotation of the capital fragment of the first metatarsal was termed the capital rotation angle (CRA) and was measured intraoperatively after the completion of scarf osteotomy. The IMA, HVA, and SRA were significantly reduced from 13.9 ± 4.9°, 34.6 ± 7.4°, and 28.7 ± 9.8° to 2.4 ± 2.3°, 7.3 ± 4.7°, and 13.4 ± 8.8°, respectively (p < .01 for all). The mean CRA was 7.0 ± 3.4° and was not significantly correlated with the reduction of IMA and SRA (p > .05 for all); nor was it significantly correlated with IMA preoperatively and postoperatively (p > .05 for all) or the reduction of SRA and IMA (p > .05). The R sign was positive in 40% (12/30) of the feet preoperatively compared to 13.3% (4/30) postoperatively (p < .001). Scarf osteotomy produced a supination effect on the capital fragment of the first metatarsal and supinated the sesamoids via lateral translation of the first metatarsal head. These changes may contribute to the correction of the pronation component of hallux valgus deformity.     

Kinematics of the first metatarsophalangeal joint

The kinematics of both the first metatarsophalangeal joint and the articulation of the hallux sesamoid bones with the metatarsal head were investigated with fifteen fresh-frozen below-the-knee amputation specimens using a radiographic technique. Six feet were of normal structural anatomy, six displayed hallux valgus, and three had hallux rigidus. Normal specimens demonstrated an average total range of motion in the sagittal plane of 111 degrees, with about 76 degrees of dorsiflexion and 34 degrees of plantar flexion. The abnormal specimens revealed a decreased total arc of motion, with a limitation of plantar flexion in feet with hallux valgus and a loss of dorsiflexion in feet with hallux rigidus. Motion analysis of the normal metatarsophalangeal joints demonstrated minimum scattering of instant centers of rotation. This was in contrast to the diseased articulations, which displayed markedly displaced instant centers of rotation located eccentrically about the metatarsal head. Surface motion in the normal joints was characterized as tangential sliding from maximum plantar flexion to moderate dorsiflexion, with some compression at maximum dorsiflexion. The feet with hallux valgus and the feet with hallux rigidus displayed distinctive patterns of distraction and jamming throughout specific portions of the range of motion in the sagittal plane. Motion of the metatarsophalangeal joint in the transverse plane concomitant with motion in the sagittal plane, which has been hypothesized by other investigators, was confirmed and quantified in this study. The feet with hallux rigidus displayed a reduction in this motion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationships Between First Metatarsal and Sesamoid Positions and Other Clinically Relevant Parameters for Hallux Valgus Surgery

Relationships between hallux valgus (HV) and other measurements within the first ray have been extensively studied. It is becoming more popular to correct HV deformity with tarsometatarsal joint arthrodesis while internally (varus) rotating the first metatarsal. This, in turn, reduces the sesamoid position when viewed in the dorsoplantar projection on radiographs. However, it has been shown that not all HV deformities have pathological external (valgus) rotation of the first metatarsal. In this study, we explored the relationships between frontal-plane rotations of the first metatarsal as well as the sesamoids, and other factors not limited to the first ray, to better understand the pathological process of HV deformity and to assist in surgical planning. We found that when adjusting for these covariates, the only factor associated with first metatarsal external rotation was having less metatarsus adductus. Sesamoid rotation, on the other hand, was independently associated with the HV angle, tibial sesamoid position, and medial column collapse. When surgically treating HV, correction of sesamoid rotation may need to be prioritized.     

Observed Changes in Radiographic Measurements of the First Ray after Frontal and Transverse Plane Rotation of the Hallux: Does the Hallux Drive the Metatarsal in a Bunion Deformity?

It is well known that the pathologic positions of the hallux and the first metatarsal in a bunion deformity are multiplanar. It is not universally understood whether the pathologic changes in the hallux or first metatarsal drive the deformity. We have observed that frontal plane rotation of the hallux can result in concurrent positional changes proximally in the first metatarsal in hallux abducto valgus. In the present study, we observed the changes in common radiographic measurements used to evaluate a bunion deformity in 5 fresh frozen cadaveric limbs. We measured the tibial sesamoid position, 1-2 intermetatarsal angle, and first metatarsal cuneiform angle on anteroposterior radiographs after frontal and transverse plane manipulation of the hallux. When the hallux was moved into an abducted and valgus position, a statistically significant increase was found in the tibial sesamoid position (p = .016). However, we did not observe a significant increase in the intermetatarsal angle (p = .070) or medial cuneiform angle (p = .309). When the hallux was manipulated into an adducted and varus position, a statistically significant decrease in the intermetatarsal angle (p = .02) and a decrease in the tibial sesamoid position (p = .016) was seen, with no significant change in the medial cuneiform angle (p = .360). We also observed a consistent rounding of the lateral aspect of the first metatarsal head and an increase in the concavity of the lateral metatarsal shaft, with valgus rotation of the hallux. From these observations, it is possible that the hallux could drive the proximal changes in the first ray that lead to metatarsus primus adducto valgus deformity.     

Influence of foot position on the measurement of first metatarsal axial rotation using the first metatarsal axial radiographs

BackgroundThe purpose of this study was to clarify 1) the measurement error of the pronation angle using the first metatarsal axial radiograph with the pronation angle along the longitudinal axis of the first metatarsal as the reference standard, 2) the influence of variability in the foot position on the measurement error, and 3) the intra- and interrater reliability of pronation angle measurement using digitally reconstructed radiographs.MethodsDigitally reconstructed radiographs of the first metatarsal were generated from the computed tomography images of 10 feet without hallux valgus (non-HV group) and 10 feet with hallux valgus (HV group). In total, 135 images were created at different degrees of supination, plantarflexion, and adduction from each foot to simulate the first metatarsal axial view. Then, the pronation angle of the first metatarsal was measured. The measurement error was determined using the mean error and 95% limits of agreement. Simple linear regression analysis was used to test the correlations of the measurement error with pronation, plantarflexion and adduction angles. The intra- and interrater reliability of measurement was assessed using the intraclass correlation coefficient and minimum detectable change values.ResultsThe mean measurement errors were 0.1° for both the non-HV and HV groups. There was no significant correlation of the measurement error with pronation, plantarflexion or adduction angles for both groups. Additionally, the intraclass correlation coefficients for the intra- and interrater reliability were more than 0.9 in both the non-HV and HV groups with the minimum detectable change values ranging from 0.7° to 1.4°.ConclusionThe measurement error of first metatarsal pronation using the axial view was clinically acceptable. The measurements were not influenced by the variability in foot position while obtaining the radiograph. The first metatarsal axial view could be used to quantify the first metatarsal coronal rotation.     

The Effect of Hallux Valgus Surgery on the Transverse Plane Hallux Proximal Phalanx Position

The objective of this investigation was to evaluate the apparent movement of the hallux proximal phalanx in the transverse plane relative to the second metatarsal following hallux valgus surgery. Pre- and postoperative radiographs of a consecutive series of 45 feet undergoing hallux valgus surgery were analyzed. Significant improvements were observed in the first intermetatarsal angle (12.4 vs 7.5 degrees; p < .001), hallux valgus angle (24.3 vs 13.4 degrees; p < .001), tibial sesamoid position (4.6 vs 2.7; p < .001), and second metatarsal-hallux proximal phalanx angle (80.1 vs 84.6 degrees; p < .001). No difference was observed in the distance between the second metatarsal bisection and the medial aspect of the tibial sesamoid (31.7 vs 31.5 mm; p = .756) nor between the second metatarsal bisection and medial aspect of the hallux proximal phalanx base (34.6 vs 34.2 mm; p = .592). Significant differences were observed between the second metatarsal bisection and the central aspect of hallux proximal phalanx base (26.5 vs 23.9 mm; p < .001) and between the second metatarsal bisection and the lateral aspect of the hallux proximal phalanx base (19.3 vs 15.4 mm; p < .001). A statistically significant difference was observed in the change of distance between the second metatarsal bisection and the medial, central, and lateral aspects of the hallux proximal phalanx base (-0.4 vs -2.6 vs -3.9 mm; p = .002). These results indicate that the hallux proximal phalanx does not translocate in the transverse plane following hallux valgus surgery, but instead pivots about the medial aspect of the joint.     

Is Double Metatarsal Osteotomy Superior to Proximal Chevron Osteotomy in Treatment of Hallux Valgus With Increased Distal Metatarsal Articular Angle?

We compared the results of proximal chevron osteotomy and double metatarsal osteotomy for hallux valgus with an increased distal metatarsal articular angle (DMAA). From October 2008 to December 2012, first metatarsal osteotomies were performed in 64 patients (69 feet) with symptomatic hallux valgus associated with an increased DMAA. Proximal chevron with Akin osteotomy and lateral soft tissue release was performed in 46 feet (PCO group); double metatarsal osteotomy and Akin osteotomy without lateral soft tissue release was performed in 23 feet (DMO group). Clinical assessments were performed using the American Orthopaedic Foot and Ankle Society (AOFAS) scale and visual analog scale (VAS). The hallux valgus angles, intermetatarsal angles, sesamoid positions, metatarsus adductus angles, and DMAAs were compared at different postoperative times. Postoperative shortening of first the metatarsal and complications were compared. The mean AOFAS scale and VAS scores showed significant improvement in both groups after surgery; however, no significant difference was observed between the 2 groups. The immediate postoperative hallux valgus angle and sesamoid position were significantly larger in DMO group; however, no intergroup difference was observed at the last follow-up visit, with the hallux valgus angle gradually increasing in the PCO group. The postoperative DMAA was significantly smaller in the DMO group. The mean shortening of the first metatarsal after surgery was significantly larger in the DMO group than in the PCO group. Transfer metatarsalgia developed in 1 foot (2.2%) in the PCO group and 2 feet (8.7%) in the DMO group. Partial avascular necrosis of the metatarsal head with advanced arthritis of the first metatarsophalangeal joint developed in 1 foot (4.3%) in the DMO group. In conclusion, no differences in the clinical and radiographic results were observed between the 2 groups for hallux valgus deformity with an increased DMAA.     

Proximal spherical metatarsal osteotomy for the foot with severe hallux valgus

BACKGROUND: A proximal spherical metatarsal osteotomy was devised to correct not only varus deviation of the first metatarsal, but also dorsiflexion. We expected to increase the medial longitudinal arch by adding plantar flexion at the osteotomy site. To investigate the limitations of this procedure for feet with severe hallux valgus, a followup study was performed on patients with preoperative hallux valgus angles greater than or equal to 40 degrees. MATERIALS AND METHODS: Forty-eight feet in 37 patients (10 male, 27 female) (60 years; range, 20 to 84 years) were investigated. Mean followup was 4 years and 1 month, ranging from 2 to 8 years. The spherical osteotomy was performed using a curved chisel. A distal soft tissue procedure was done at the same time. Twenty feet received combined operations for their combined deformities. RESULTS: While 81% of patients were satisfied with the results, 50% of those with preoperative hallux valgus angles greater than or equal to 50 degrees had postoperative hallux valgus angle greater than or equal to 20 degrees. In these patients, correction of metatarsus primus varus was good, but correction of valgus deviation of the hallux was fair. Mean correction toward plantar flexion was 1.5 degrees and no increase in arch height was achieved. CONCLUSION: The proximal spherical osteotomy could consistently achieve satisfactory results for the patients with hallux valgus angles less than 50 degrees. However, the corrections were worse in feet with more severe deformities. Furthermore, plantarflexion at the osteotomy site was offset by displacement at the first tarsometatarsal joint. If plantarflexion is indispensable, arthrodesis of the tarsometatarsal joint is recommended.     

Hallux valgus repair. DuVries modified McBride procedure

The DuVries modification of the McBride procedure was investigated in 72 feet in 47 patients with hallux valgus deformity. Overall, the patient satisfaction rate was 92%. The hallux valgus averaged 32 degrees preoperatively, and 16 degrees postoperatively. The intermetatarsal angle averaged 14 degrees preoperatively and 9 degrees postoperatively. Anatomic realignment of the remaining tibial sesamoid was achieved in 28% of the feet. As a result of realignment of the first metatarsophalangeal joint, the intractable plantar keratosis beneath the second metatarsal head was resolved in 19 of 20 feet. Six patients developed a hallux varus deformity that averaged 7.5 degrees. All cases of hallux varus had medial displacement of the tibial sesamoid. The number of patients who could withstand unrestricted shoe wear increased from ten patients preoperatively to 30 patients postoperatively. The patient activity level increased in two thirds of the cases. The distal soft-tissue procedure produces the most predictable correction in patients with a hallux valgus deformity measuring less than 30 degrees. In more severe deformities, a proximal metatarsal osteotomy should be added to the procedure.     

Effect of metatarsophalangeal joint position on the reliability of the tangential sesamoid view in determining sesamoid position

BACKGROUND: Lateral displacement of the sesamoids of the first toe relative to the metatarsal head is a common finding in hallux valgus deformity. Several methods have been described for quantifying the amount of subluxation from anteroposterior radiographs but a tangential sesamoid radiograph has been determined to be the best view to evaluate sesamoid displacement. METHOD: We evaluated the sesamoid position at different angles of the first metatarsophalangeal (MTP) joint to determine the effect of first MTP joint dorsiflexion on sesamoid position when tangential sesamoid view radiographs are made. Sesamoid positions of 22 feet with hallux valgus were graded from the short axis computed tomography (CT) images obtained with the MTP joint in 0, 35, and 70 degrees of dorsiflexion. RESULTS: Approximation of the sesamoids to reduction was apparent as dorsiflexion of the first MTP joint increased. CONCLUSION: Different dorsiflexion degrees of the first MTP joint when tangential sesamoid radiographs are made modulate the position of the sesamoids and may lead to misclassification on grading.     

Evaluation of the 1st metatarso-sesamoid joint using standing CT — The Stanmore classification

Background

Little is understood about the role that relative sesamoid displacement and chondral wear have on outcome after hallux valgus (HV) surgery. All existing methods to evaluate relative sesamoid displacement have limitations and furthermore, there have been no radiographic studies evaluating metatarso-sesamoid joint wear. Standing CT scan circumvents many of the existing problems in evaluation of relative sesamoid displacement, and also enables the first radiographic study assessing metatarso-sesamoid joint wear.