Radiographic measurement of the congruence angle according to Merchant: validity, reproducibility, and limits
Abstract Purpose The objective of this study was to analyze the intra- and interobserver variability of this measurement according to a strict methodology and on a representative sample of the general population, as well as to identify the possible difficulties of measurement in case of patellar or...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2023-01-01
|
| Series: | Knee Surgery & Related Research |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s43019-023-00175-5 |
| _version_ | 1797952495246376960 |
|---|---|
| author | M. Severyns J. Mallet B. Santoni T. Barnavon A. Germaneau T. Vendeuvre M. Drame |
| author_facet | M. Severyns J. Mallet B. Santoni T. Barnavon A. Germaneau T. Vendeuvre M. Drame |
| author_sort | M. Severyns |
| collection | DOAJ |
| description | Abstract Purpose The objective of this study was to analyze the intra- and interobserver variability of this measurement according to a strict methodology and on a representative sample of the general population, as well as to identify the possible difficulties of measurement in case of patellar or trochlear dysplasia. Methods This observational study involved radiographic analysis by three independent observers of a total of 50 patients who had a loaded patellofemoral X-ray taken with the knee flexed to 45°. An initial reading was taken to measure the angle of the trochlear sulcus, the Merchant angle, and to classify the knees according to a possible trochlear dysplasia and/or patellar dysplasia according to Wiberg. A second measurement was then performed to analyze intraobserver agreement. Interobserver agreement was measured on all radiographic measurements (n = 100). Results The Merchant patellofemoral congruence angle showed good intraobserver concordance ranging from 0.925 (95% CI 0.868–0.957) to 0.942 (95% CI 0.898–0.967), as well as interobserver concordance ranging from 0.795 (95% CI 0.695–0.862) to 0.914 (95% CI 0.872–0.942). Poor results were found in terms of interobserver concordance on the measurement of the Merchant angle in case of stage 3 Wiberg patella ranging from 0.282 (95% CI −0.920 to 0.731) to 0.611 (95% CI 0.226–0.892). Conclusion Congruence angle is one of most commonly used measurements for patellar tracking. However, the convexity of the patellar surface makes it difficult to identify the patellar apex on its intraarticular facet, making the measurement of the Merchant congruence angle unreliable and not very reproducible in cases of stage 3 Wiberg patella. Registration N°IRB 2021/139 |
| first_indexed | 2024-04-10T22:47:15Z |
| format | Article |
| id | doaj.art-8e0afbf7e5654d22947cdfec45209641 |
| institution | Directory Open Access Journal |
| issn | 2234-2451 |
| language | English |
| last_indexed | 2024-04-10T22:47:15Z |
| publishDate | 2023-01-01 |
| publisher | BMC |
| record_format | Article |
| series | Knee Surgery & Related Research |
| spelling | doaj.art-8e0afbf7e5654d22947cdfec452096412023-01-15T12:14:57ZengBMCKnee Surgery & Related Research2234-24512023-01-013511610.1186/s43019-023-00175-5Radiographic measurement of the congruence angle according to Merchant: validity, reproducibility, and limitsM. Severyns0J. Mallet1B. Santoni2T. Barnavon3A. Germaneau4T. Vendeuvre5M. Drame6Department of Orthopaedic Surgery, Clinique Porte OcéaneDepartment of Orthopaedic Surgery, Clinique Porte OcéaneDepartment of Orthopaedic Surgery, Clinique Porte OcéaneDepartment of Orthopaedic Surgery, Clinique Porte OcéanePprime Institut UP 3346, CNRS, University of PoitiersPprime Institut UP 3346, CNRS, University of PoitiersDepartment of Clinical Research and Innovation, University Hospital of MartiniqueAbstract Purpose The objective of this study was to analyze the intra- and interobserver variability of this measurement according to a strict methodology and on a representative sample of the general population, as well as to identify the possible difficulties of measurement in case of patellar or trochlear dysplasia. Methods This observational study involved radiographic analysis by three independent observers of a total of 50 patients who had a loaded patellofemoral X-ray taken with the knee flexed to 45°. An initial reading was taken to measure the angle of the trochlear sulcus, the Merchant angle, and to classify the knees according to a possible trochlear dysplasia and/or patellar dysplasia according to Wiberg. A second measurement was then performed to analyze intraobserver agreement. Interobserver agreement was measured on all radiographic measurements (n = 100). Results The Merchant patellofemoral congruence angle showed good intraobserver concordance ranging from 0.925 (95% CI 0.868–0.957) to 0.942 (95% CI 0.898–0.967), as well as interobserver concordance ranging from 0.795 (95% CI 0.695–0.862) to 0.914 (95% CI 0.872–0.942). Poor results were found in terms of interobserver concordance on the measurement of the Merchant angle in case of stage 3 Wiberg patella ranging from 0.282 (95% CI −0.920 to 0.731) to 0.611 (95% CI 0.226–0.892). Conclusion Congruence angle is one of most commonly used measurements for patellar tracking. However, the convexity of the patellar surface makes it difficult to identify the patellar apex on its intraarticular facet, making the measurement of the Merchant congruence angle unreliable and not very reproducible in cases of stage 3 Wiberg patella. Registration N°IRB 2021/139https://doi.org/10.1186/s43019-023-00175-5Congruence angleFemoro-patellar jointWiberg classification |
| spellingShingle | M. Severyns J. Mallet B. Santoni T. Barnavon A. Germaneau T. Vendeuvre M. Drame Radiographic measurement of the congruence angle according to Merchant: validity, reproducibility, and limits Knee Surgery & Related Research Congruence angle Femoro-patellar joint Wiberg classification |
| title | Radiographic measurement of the congruence angle according to Merchant: validity, reproducibility, and limits |
| title_full | Radiographic measurement of the congruence angle according to Merchant: validity, reproducibility, and limits |
| title_fullStr | Radiographic measurement of the congruence angle according to Merchant: validity, reproducibility, and limits |
| title_full_unstemmed | Radiographic measurement of the congruence angle according to Merchant: validity, reproducibility, and limits |
| title_short | Radiographic measurement of the congruence angle according to Merchant: validity, reproducibility, and limits |
| title_sort | radiographic measurement of the congruence angle according to merchant validity reproducibility and limits |
| topic | Congruence angle Femoro-patellar joint Wiberg classification |
| url | https://doi.org/10.1186/s43019-023-00175-5 |
| work_keys_str_mv | AT mseveryns radiographicmeasurementofthecongruenceangleaccordingtomerchantvalidityreproducibilityandlimits AT jmallet radiographicmeasurementofthecongruenceangleaccordingtomerchantvalidityreproducibilityandlimits AT bsantoni radiographicmeasurementofthecongruenceangleaccordingtomerchantvalidityreproducibilityandlimits AT tbarnavon radiographicmeasurementofthecongruenceangleaccordingtomerchantvalidityreproducibilityandlimits AT agermaneau radiographicmeasurementofthecongruenceangleaccordingtomerchantvalidityreproducibilityandlimits AT tvendeuvre radiographicmeasurementofthecongruenceangleaccordingtomerchantvalidityreproducibilityandlimits AT mdrame radiographicmeasurementofthecongruenceangleaccordingtomerchantvalidityreproducibilityandlimits |