Cam impingement: defining the presence of a cam deformity by the alpha angle: data from the CHECK cohort and Chingford cohort.
INTRODUCTION: Cam impingement is characterized by abnormal contact between the proximal femur and acetabulum caused by a non-spherical femoral head, known as a cam deformity. A cam deformity is usually quantified by the alpha angle; greater alpha angles substantially increase the risk for osteoarthr...
| Main Authors: | , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2014
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| _version_ | 1826288959333859328 |
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| author | Agricola, R Waarsing, J Thomas, G Carr, A Reijman, M Bierma-Zeinstra, S Glyn-Jones, S Weinans, H Arden, N |
| author_facet | Agricola, R Waarsing, J Thomas, G Carr, A Reijman, M Bierma-Zeinstra, S Glyn-Jones, S Weinans, H Arden, N |
| author_sort | Agricola, R |
| collection | OXFORD |
| description | INTRODUCTION: Cam impingement is characterized by abnormal contact between the proximal femur and acetabulum caused by a non-spherical femoral head, known as a cam deformity. A cam deformity is usually quantified by the alpha angle; greater alpha angles substantially increase the risk for osteoarthritis (OA). However, there is no consensus on which alpha angle threshold to use to define the presence of a cam deformity. AIM: To determine alpha angle thresholds that define the presence of a cam deformity and a pathological cam deformity based on development of OA. METHODS: Data from both the prospective CHECK cohort of 1002 individuals (45-65 years) and the prospective population-based Chingford cohort of 1003 women (45-64 years) with respective follow-up times of 5 and 19 years were combined. The alpha angle was measured at baseline on anteroposterior radiographs, from which a threshold for the presence of a cam deformity was determined based on its distribution. Further, a pathological alpha angle threshold was determined based on the highest discriminative ability for development of end-stage OA at follow-up. RESULTS: A definite bimodal distribution of the alpha angle was found in both cohorts with a normal distribution up to 60°, indicating a clear distinction between normal and abnormal alpha angles. A pathological threshold of 78° resulted in the maximum area under the ROC curve. CONCLUSION: Epidemiological data of two large cohorts shows a bimodal distribution of the alpha angle. Alpha angle thresholds of 60° to define the presence of a cam deformity and 78° for a pathological cam deformity are proposed. |
| first_indexed | 2024-03-07T02:21:36Z |
| format | Journal article |
| id | oxford-uuid:a41b68b0-633d-4f73-9e6b-69352480cbc8 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:21:36Z |
| publishDate | 2014 |
| record_format | dspace |
| spelling | oxford-uuid:a41b68b0-633d-4f73-9e6b-69352480cbc82022-03-27T02:31:43ZCam impingement: defining the presence of a cam deformity by the alpha angle: data from the CHECK cohort and Chingford cohort.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:a41b68b0-633d-4f73-9e6b-69352480cbc8EnglishSymplectic Elements at Oxford2014Agricola, RWaarsing, JThomas, GCarr, AReijman, MBierma-Zeinstra, SGlyn-Jones, SWeinans, HArden, NINTRODUCTION: Cam impingement is characterized by abnormal contact between the proximal femur and acetabulum caused by a non-spherical femoral head, known as a cam deformity. A cam deformity is usually quantified by the alpha angle; greater alpha angles substantially increase the risk for osteoarthritis (OA). However, there is no consensus on which alpha angle threshold to use to define the presence of a cam deformity. AIM: To determine alpha angle thresholds that define the presence of a cam deformity and a pathological cam deformity based on development of OA. METHODS: Data from both the prospective CHECK cohort of 1002 individuals (45-65 years) and the prospective population-based Chingford cohort of 1003 women (45-64 years) with respective follow-up times of 5 and 19 years were combined. The alpha angle was measured at baseline on anteroposterior radiographs, from which a threshold for the presence of a cam deformity was determined based on its distribution. Further, a pathological alpha angle threshold was determined based on the highest discriminative ability for development of end-stage OA at follow-up. RESULTS: A definite bimodal distribution of the alpha angle was found in both cohorts with a normal distribution up to 60°, indicating a clear distinction between normal and abnormal alpha angles. A pathological threshold of 78° resulted in the maximum area under the ROC curve. CONCLUSION: Epidemiological data of two large cohorts shows a bimodal distribution of the alpha angle. Alpha angle thresholds of 60° to define the presence of a cam deformity and 78° for a pathological cam deformity are proposed. |
| spellingShingle | Agricola, R Waarsing, J Thomas, G Carr, A Reijman, M Bierma-Zeinstra, S Glyn-Jones, S Weinans, H Arden, N Cam impingement: defining the presence of a cam deformity by the alpha angle: data from the CHECK cohort and Chingford cohort. |
| title | Cam impingement: defining the presence of a cam deformity by the alpha angle: data from the CHECK cohort and Chingford cohort. |
| title_full | Cam impingement: defining the presence of a cam deformity by the alpha angle: data from the CHECK cohort and Chingford cohort. |
| title_fullStr | Cam impingement: defining the presence of a cam deformity by the alpha angle: data from the CHECK cohort and Chingford cohort. |
| title_full_unstemmed | Cam impingement: defining the presence of a cam deformity by the alpha angle: data from the CHECK cohort and Chingford cohort. |
| title_short | Cam impingement: defining the presence of a cam deformity by the alpha angle: data from the CHECK cohort and Chingford cohort. |
| title_sort | cam impingement defining the presence of a cam deformity by the alpha angle data from the check cohort and chingford cohort |
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