Aims Recently, there has been considerable interest in quantifying the associations between bony abnormalities around and in the hip joint and osteoarthritis (OA). Our aim was to investigate the relationships between acetabular undercoverage, acetabular overcoverage, and femoroacetabular impingement (FAI) with OA of the hip, which currently remain controversial.
Materials and Methods A total of 545 cadaveric skeletons (1090 hips) from the Hamann-Todd osteological collection were obtained. Femoral head volume (FHV), acetabular volume (AV), the FHV/AV ratio, acetabular version, alpha angle and anterior femoral neck offset (AFNO) were measured. A validated grading system was used to quantify OA of the hip as minimal, moderate, or severe. Multiple linear and multinomial logistic regression were used to determine the factors that correlated independently with the FHV, AV, and the FHV/AV ratio.
Results Female cadavers had smaller FHVs (standardised beta -0.382, p < 0.001), and AVs (standardised beta -0.351, p < 0.001), compared with male patients, although the FHV/AV ratio was unchanged. Every 1° increase in alpha angle increased the probability of having moderate OA of the hip compared with minimal OA by 7.1%. Every 1 mm decrease in AFNO increased the probability of having severe or moderate OA of the hip, compared with minimal OA, by 11% and 9%, respectively. The relative risk ratios of having severe OA of the hip compared with minimal OA were 7.2 and 3.3 times greater for acetabular undercoverage and overcoverage, respectively, relative to normal acetabular cover.
Conclusion Acetabular undercoverage and overcoverage were independent predictors of increased OA of the hip. The alpha angle and AFNO had modest effects, supporting the hypothesis that bony abnormalities both in acetabular dysplasia and FAI are associated with severe OA.
Cite this article: Bone Joint J 2017;99-B:432–9.
- Osteoarthritis of the hip
- Femoroacetabular impingement
- Acetabular dysplasia
- Acetabular cover
- Alpha angle
D. S. Weinberg: Conceptualised the study, Project design, Data collection, Data analysis, Manuscript preparation, Critically reviewed and edited the final manuscript.
D. F. K. Wiliamson: Data collection, Data analysis, Critically reviewed and edited the final manuscript.
M. B. Mills: Project design, Manuscript preparation, Critically reviewed and edited the final manuscript.
R. W. Liu: Organised the research team, Conceptualised the study, Project design, Data analysis, Manuscript preparation, Critically reviewed and edited the final manuscript.
Although none of the authors has received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this article, benefits have been or will be received but will be directed solely to a research fund, foundation, educational institution, or other non- profit organization with which one or more of the authors are associated.
This article was primary edited by E. Moulder and first proof edited by J. Scott.
- Received March 26, 2016.
- Accepted December 2, 2016.
- ©2017 The British Editorial Society of Bone & Joint Surgery