Radiological Evaluation of Volar Cortical Angle in the Anatolian Population / Evaluación Radiológica del Ángulo Cortical Volar en la Población Anatoliana

SUMMARY: Distal radius fractures are the most common fractures of the upper limb. The most commonly used method in the repair of these fractures is volar locking plates. Recently, the frequency of removal of volar locking plates after surgery has increased. There are many factors in its reduction. Anatomically, incompatibility of the distal end of the radius with volar locking plates is one of them. In previous studies, different volar cortical angle (VCA) values were found in other races. For this reason, this study aimed to determine the mean values by making VCA measurements of the Anatolian population. The study was designed retrospectively. In the study, measurements were made on computed tomography (CT) images of the distal end of the radius of 53 men and 28 women. Radial width, intermediate volar angle, and radial volar angle were measured in the images. On average, the radius width was 23.35±1.96 mm, and the intermediate volar angle was 26.02±.3.83°, radial volar angle was 24±3.07°. Radial width, intermediate volar angle, and radial volar angle differed significantly by gender (p<0.001). A significant correlation was found between radius width, intermediate volar angle, and radial volar angle values (p<0.001). It has been determined that the Anatolian population has a different VCA value than the European, Asian, and other populations. When using volar locking plates in distal radius fracture surgery, volar locking plates should be selected by considering the average values of the races.

Las fracturas del radio distal son las fracturas más comunes del miembro superior. El método más utilizado en la reparación de estas fracturas son las placas de bloqueo volar. Recientemente, ha aumentado la frecuencia de extracción de placas de bloqueo volar después de la cirugía. Existen muchos factores en su reducción y anatómicamente, la incompatibilidad de la extremidad distal del radio con las placas de bloqueo volar es una de ellas. En estudios anteriores, se encontraron diferentes valores del ángulo cortical volar (VCA) en otras grupos. Por esta razón, este estudio tuvo como objetivo determinar los valores medios, realizando mediciones de VCA de la población de Anatolia. El estudio fue diseñado de manera retrospectiva. En el estudio, se realizaron mediciones en imágenes de tomografía computarizada (TC) de la extremidad distal del radio de 53 hombres y 28 mujeres. En las imágenes se midieron el ancho radial, el ángulo volar intermedio y el ángulo volar radial. En promedio, el ancho del radio fue de 23,35 ± 1,96 mm, el ángulo volar intermedio fue de 26,02 ± 3,83° y el ángulo volar radial fue de 24 ± 3,07°. El ancho radial, el ángulo volar intermedio y el ángulo volar radial difirieron significativamente según el sexo (p<0,001). Se encontró una correlación significativa entre los valores del ancho del radio, el ángulo volar intermedio y el ángulo volar radial (p<0,001). Se ha determinado que la población de Anatolia tiene un valor de VCA diferente al de las poblaciones europeas, asiáticas y otras. Cuando se utilizan placas de bloqueo volar en cirugía de fractura de la extremidad distal del radio, las placas deben seleccionarse considerando los valores promedio de los individuos de diferentes grupos.

Analysis of Three-Dimensional Anatomical Variance and Fit of the Distal Radius to Current Volar Locking Plate Designs.

Purpose: Distal radius fractures are the most common upper-extremity fracture and are increasingly being treated surgically with precontoured volar locking plates. It is not currently known whether existing implant designs are anatomically accurate and whether this has clinical implications. The objective of this study was to determine whether anatomic alignment of the distal radius corresponds accurately to modern volar locking plate designs, including any sex-linked differences in morphology of the distal radius. It was hypothesized that the 2 plates examined would show differences in watershed line (WSL) overlap and that female specimens would have a larger overlap compared with males owing to a decrease in plate-WSL border distances. Methods: We used 3-dimensional models of 20 cadaver arms (10 female: mean age, 88.7 ± 4.6 years [range, 82-97 years]; and 10 male: mean age, 86 ± 3.6 years [range, 81-91 years]) to create 3-dimensional computed tomography models of the distal radius. Virtual models of 2 common volar plates were created and were used to place the plate virtually onto the distal radii. Outcome measures included the volar cortical angle of the bone and plate, the definition of the WSL subsequently followed by quantitative distance and overlap measures, and percent contact between the plate and the distal radius. Results: Both sexes showed an decrease (approximately 7°) in average volar cortical angle measure from medial to lateral columns that was statistically significantly smaller on the lateral column (males: 38°; females: 29°) compared with the medial column (males: 45°; females: 36°). Watershed line overlap ranged from 0% to 34.8% with statistically significant differences between sexes. Average border distance for females was 2.7 mm, compared with 3.8 mm for males. Maximum percent contact of 22.0% was observed at a 0.3-mm threshold. Conclusions: Distal radius fractures are common in elderly female patients, yet clinically available plates have important differences in WSL overlap between sexes, and with minimal contact. Female specimens had more WSL overlap than did males. This indicates the need for volar locking plates to be redesigned to factor in anatomical features of individual patients with a particular focus on sex differences. Clinical relevance: New plate designs should focus on providing smaller head sizes that are more accurately tailored to the natural contours of the volar distal radius. It is recommended that future studies incorporate expertise from multiple surgeons to diversify and further understand plate placement strategies.

Age-Related Variations in Volar Cortical Angle of the Distal Radius.

Background: The ideal volar locking plate for the treatment of distal radius fracture should anatomically fit the volar surface of the distal radius. The purpose of this study was to measure the volar cortical angle (VCA) of uninjured adult distal radii to determine how well the VCA matches that of modern volar locking plates and whether variations in the VCA are related to demographic factors. Methods: A retrospective radiographic analysis of 273 uninjured adult distal radii was performed. Patients were stratified into age quintiles: less than 27 years, 27 to 43 years, 44 to 51 years, 52 to 64 years, and 65 years or older. The VCA was measured on lateral wrist radiographs, and patient demographics, including age and sex, were collected. Multivariable linear regression analyses were performed to determine the relationship between VCA and demographic factors. Results: The VCA ranged from 23.2° to 42.6°, with a mean of 32.2° (SD = 3.79). Mean VCA was 32.8 (SD = 4.17) in the youngest cohort (<27 years) and 30.4 (SD = 3.63) in the oldest cohort (>65 years). Mean VCA decreased with age, approximately 0.04° per year after adjusting for sex. Men had a 1.6° greater VCA than women after adjusting for age. Conclusion: Mean VCA was greater than the VCA of modern volar locking plates. The VCA decreased with age in both men and women, and men had a greater VCA than women. Such differences must be taken into account to avoid malreduction, tendon irritation, or intra-articular screw placement using current volar plate designs.

The distal radius palmar cortical angle in adolescent versus adult populations.

PURPOSE: Volar distal radius plates are pre-contoured to aid restoration of anatomy during open reduction internal fixation of distal radius fractures. Incorrectly contoured plates can result in malreduction, leading to malunion, pain, and loss of function. The purpose of this study was to investigate whether adolescent distal radius anatomy on the palmar cortical surface differs from that in adults, in order to determine whether adult plates are suitable for use in adolescents. METHODS: Lateral wrist radiographs were used to measure the distal radius palmar cortical angle (PCA) in adolescent age groups (12-13, 14-15, and 16-17 years old) and compared to a skeletally mature control group (30-50 years old). Two assessors measured 423 PCAs twice. RESULTS: There was a statistically significant ( p = <0.05) difference in the PCA of the control group compared to each adolescent group. The mean PCA for both males and females decreased as age increased (increasing curvature of the volar distal radius with age). The mean PCA (male/female) was 164.38°/163.00° in ages 12-13, 162.14°/160.92° in ages 14-15, 157.52°/158.18° in ages 16-17, and 149.65°/154.03° in the control group aged 30-50 years. Agreement between assessors was high with an Interclass correlation coefficient (ICC) of 0.97. CONCLUSION: There is a statistically significant and potentially clinically important difference in the curvature of the distal radius volar cortex between adolescents and adults. This difference persists even in the 16-17 age group. As the PCA curvature is significantly greater in adults compared to adolescents, plates pre-contoured for adults may lead to malreduction of distal radius fractures into flexion in adolescent patients.

Do volar locking plates fit the volar cortex of the distal radius?

The purpose of this study was to measure the volar cortical angles of the commercially available volar locking plates and evaluate how well they fit the distal radius. We measured the volar cortical angles of the radial and intermediate columns of eight volar locking plates and compared them with the volar cortical angles of 90 cadaver distal radii. The mean radial and intermediate column volar cortical angles of the wider plates were significantly larger than those of narrower plates. The mean radial and intermediate column volar cortical angles were significantly larger in wider radii than narrower radii. The width of the distal radius did not correlate well with the mean volar cortical angles of the radial and intermediate columns. LEVEL OF EVIDENCE: IV.