The Etiology of Femoroacetabular Impingement: What We Know and What We Don’t

CONTEXT: Several risk factors may cause femoroacetabular impingement (FAI). Knowledge of causation would identify patients for early intervention, prior to the development of painful intra-articular damage. DATA SOURCES: PubMed, MEDLINE, EMBASE, and related article reference lists were screened for relevant studies published between January 2000 and December 2013. STUDY SELECTION: Inclusion criteria were (1) etiology of FAI, (2) original FAI clinical data, and (3) English language. Case reports of fewer than 3 patients were excluded. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 4. RESULTS: In all, 754 studies were screened, with 18 meeting the eligibility criteria. There were 13 comparative observational studies and 5 case series. The studies pertained to intrinsic patient factors (n = 2), activity/developmental factors (n = 8), hip disease (n = 5), postsurgical changes (n = 2), and malunion after hip fracture (n = 1). CONCLUSION: A combination of intrinsic patient and developmental factors, activities involving repetitive hip motion, pediatric hip disease, and hip-related surgical procedures may contribute to the development of FAI.