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Review
. 2025 Jun 20;17(6):e86461.
doi: 10.7759/cureus.86461. eCollection 2025 Jun.

Anatomical Mechanisms of Femoroacetabular Impingement and Its Role in the Progression to Hip Osteoarthritis: A Systematic Review

Sundip Charmode  1 , Sudhir Shyam Kushwaha  2 , Abhishek Kumar Mishra  3 , Simmi Mehra  1
Affiliations
Review

Anatomical Mechanisms of Femoroacetabular Impingement and Its Role in the Progression to Hip Osteoarthritis: A Systematic Review

Sundip Charmode et al. Cureus. .

Abstract

Femoroacetabular impingement (FAI) causes hip pain because of unusual bone shapes at the area where the femur connects to the hip (cam-type) or at the hip socket (pincer-type). Due to the rarity of hip osteoarthritis, people in India often overlook FAI. Significant knowledge gaps exist in the underlying pathophysiology of FAI, impacting its progression. This study aims to look at the shape changes in the femoral head-neck junction in FAI and how these changes relate to the development of hip joint osteoarthritis. We chose original reviews, book chapters, and controlled trials written in English about the causes, symptoms, and progression of FAI that were published between January 2015 and December 2024 from the PubMed/Medline and Scopus databases. Case reports, series, editorials, commentaries, abstracts, and preprints were excluded. The risk of bias in systematic reviews (ROBIS) tool was used to assess the risk of bias in selected studies, and a standardized data extraction checklist was used to obtain pertinent data for synthesis. This research protocol was prospectively registered in the International Prospective Register of Systematic Reviews (PROSPERO) under registration ID CRD42025638992. A PubMed and Medline search using the MeSH term "femoro-acetabular impingement" yielded 3315 publications. We recorded 327 articles after filtering for English, humans only, no preprints, and all ages. Based on the title and abstract, 39 articles were shortlisted after a thorough review by two investigators, who finally selected 30 articles (four systematic reviews, 18 original studies, six review articles, one clinical trial, and one book chapter) for analysis. FAI appears to be primarily mechanical rather than inflammatory, with radiographic findings often not correlating with clinical severity. As the skeleton matures, the angle of the acetabulum increases, and early closing of the triradiate cartilage leads to pincer-type FAI.

Keywords: acetabular version; cam; femoro-acetabular impingement; hip joint osteoarthritis; pincer; skeletal maturity; systematic review.

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Conflict of interest statement

Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

Figures

Figure 1
Figure 1. PRISMA flow diagram showing the step-by-step literature search
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