ePoster #802 - ISHA Annual Scientific Meeting 2016

Dynamic Motion Analysis And The Diagnosis Of Ischiofemoral Impingement

Emily Anne Wright, BSc, MbCHb, London, No UNITED KINGDOM
Giles Hugo Stafford, MBBS, BSc, FRCS, London UNITED KINGDOM

South West London Elective Orthopaedic Centre, London, London, UNITED KINGDOM

FDA Status Not Applicable

Summary: Retrospective Case Controlled Series analysing the use of Dynamic Motion Analysis in diagnosing Ischiofemoral Impingement

Introduction: Ischiofemoral Impingement (IFI) can be a diagnostic challenge. The condition is caused by narrowing of the ischiofemoral space and subsequent impingement between the ischium and lesser trochanter of the femur. This restricts hip movement particularly hip extension, adduction and external rotation. The purpose of this study is to assess the ability of dynamic motion analysis (DMA) to diagnose IFI by identifying subjects presenting with hip pain, and restricted hip extension, adduction and external rotation on DMA, and then comparing results to MRI and CT imaging, treatment and clinical outcomes. Methods: Thirty-one subjects had =15° of hip extension, adduction and external rotation on DMA, suggesting the presence of IFI. Thirty subjects in the control group had a minimum of 15° hip extension, adduction and external rotation on DMA. MRI and CT imaging of all subjects were reviewed by a Consultant Orthopaedic Surgeon who measured the ischiofemoral distance and assessed for signs of IFI such as quadratus femoris oedema (QF). Imaging results were correlated with treatment and clinical outcomes. Results: Subjects with indicated IFI on DMA had significantly narrower ischiofemoral distance compared to the control group (20.86mm vs 35.79mm p=0.00), larger femoral neck anteversion angles (19.83° vs 10.89° p=0.001) and a higher proportion of QF oedema (11 vs 3 p=0.0031). There was a positive correlation between degrees of hip extension, external rotation, adduction and IFI distance (r 0.621 p=0.00). There were significantly more females than males with suspected IFI on DMA (26 vs 5). When we merged males and females from both groups, females generally had significantly narrower IFI distance compared to males (23.6 vs 32.5 p=0.00). However, most subjects in the suspected IFI and control groups were primarily diagnosed with femoroacetabular impingement (FAI) (8 vs 17 p=0.022), labral tear (12 vs 6 p=0.114) and/or degenerative changes (5 vs 1 p=0.120). Treatment of subject’s primary diagnosis, either surgical or conservative, improved symptoms. Conclusion: Subjects with reduced hip extension, adduction and external rotation did not have abnormally reduced ischiofemoral distances compared to measurements described in published literature but were significantly narrower when compared to the control group. The majority of subjects with suspected IFI on DMA were female. The anatomy of the female pelvis would explain why these subjects had a narrower ischiofemoral distance than the control group who were evenly matched for males and females. Furthermore, none of the subjects with suspected IFI on DMA were diagnosed with the condition clinically despite having narrow IFI distances and varying levels of QF oedema. Addressing other pathology such as FAI successfully treated all these patients. This therefore suggests that IFI is may often be a radiological diagnosis which may not always not translate clinically.