Femoroacetabular impingement and risk factors: a study of 50 cases

Orthop Surg. 2011 Nov;3(4):236-41. doi: 10.1111/j.1757-7861.2011.00157.x.


Objective: To study the asphericity of the femoral head in femoroacetabular impingement using the radiological indices alpha angle and triangular index, and correlation with risk factors.

Methods: The study was conducted retrospectively from January 2008 to June 2010 on 50 consecutive patients with suspected cam type femoroacetabular impingement of the hip who reported to the orthopaedics outpatients department of the Postgraduate Institute of Medical Education and Research. Ten controls were also used in the study. Radiographs of the affected hip were taken and then the alpha angle and triangular index were measured and correlated with various risk factors.

Results: In the anteroposterior view the alpha angle range was from 55° to 106° for the cases and from 54° to 70° for the controls. In the lateral view the range was from 62° to 104° for the cases and from 54° to 62° for the controls. The mean alpha angle in the anteroposterior view was measured as 75°± 10° in the cases and 61°± 6° in the controls, and the mean in the lateral view was 74°± 8° in the cases and 58°± 6° for the controls. The triangular index range in the radiographs was from 1 to 7 in the cases and from 0 to 1 for the controls. The mean triangular index in the radiographs was 2.9 ± 1.2 for the cases and 0.2 ± 0.4 for the controls.

Conclusion: There was no significant correlation between the age and gender of the patient and the femoroacetabular impingement. However, there was significant correlation between the body mass index of the patient and the femoroacetabular impingement.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Age Distribution
  • Aged
  • Arthralgia / epidemiology*
  • Arthralgia / physiopathology
  • Body Mass Index
  • Case-Control Studies
  • Female
  • Femoracetabular Impingement / diagnostic imaging*
  • Femoracetabular Impingement / epidemiology*
  • Femoracetabular Impingement / physiopathology
  • Follow-Up Studies
  • Hip Joint
  • Humans
  • Male
  • Middle Aged
  • Pain Measurement
  • Radiography
  • Range of Motion, Articular / physiology*
  • Reference Values
  • Retrospective Studies
  • Risk Factors
  • Severity of Illness Index
  • Sex Distribution
  • Young Adult