Response to Letter to Editor

In the letter to the editor regarding “Symptomatic herniation pit of the femoral neck: a case report,” Dr Wettstein et al (J Manipulative Physiol Ther 2005;28:449-51) draw a comparison between the case described and recent descriptions of femoroacetabular impingement syndrome (FAI).1, 2, 3 After reviewing some of the literature they cited, I find their observation to be valid. Recent publications1, 2 have brought the original theory regarding the pathomechanics leading to the development of herniation pits into question, suggesting that they may not be related to synovial invagination subsequent to tight capsular and associated structures and repetitive hip extension. They may be best explained by direct compressive and shear forces subsequent to morphological abnormalities of the femoral head and neck, acetabulum, or both.2 The case in question appears to fit the clinical presentation of FAI with reproduction of the symptoms upon hip flexion, internal rotation, and adduction. The radiographs are suggestive of the cam type of FAI with a mildly aspheric femoral head.

Unfortunately, there was no evidence of labral damage on the magnetic resonance image; however, a magnetic resonance arthrogram was not performed and may have provided more conclusive evidence of FAI. Accordingly, the diagnosis is typically confirmed surgically, which was not an option for the patient because of the relatively low level of disability experienced and negligible effect on his daily activities.

Leunig et al2 provide the most detailed discussion of herniation pits and their origin, clinical significance, and relationship to FAI and should be reviewed by chiropractic radiologists and clinicians, particularly those who treat athletic populations. It should be noted that the evidence to support the latest discussion of the etiology of herniation pits was published while the case report was in queue for publication in Journal of Manipulative and Physiological Therapeutics and was not available for inclusion in the discussion.1, 2, 3 Going forward, I thank the letter authors for their input and suggest that there is evidence to support that herniation pits or fibrocystic changes of the femoral neck should no longer be considered incidental findings and may be an indicator of not only FAI but also potentially more debilitating degenerative changes to follow.