We have much to say on this topic. A few years ago I was doing some lectures on Hip Rim syndromes (ARS: Acetabular Rim Syndromes) for an imaging center and realized the lack of clinical knowledge on the topic. Recently, we have been receiving some referrals and emails regarding and we figured it was time to “hit the hip” topic for awhile.
Here is an article to start with. It has some basic info. If you want to be able to follow our progression of Rim Syndromes and labral issues and how to approach them clinically etc start here (and, if you are an athlete with hip issues, there will be understandable and usable info for you as well as the week progresses). We have some nice powerpoint presentations on this stuff too, we are looking for a way to make them available for you as well.
**** Here is our main problem with the article, as admitted by the authors……… “** "Clinical Relevance: Although this study does not include muscular forces across the hip joint, it does provide a clue as to the stresses about the labrum through the complete range of motions of the hip, which may help in providing a better understanding of the cause of labral tears and in the protection of labral repairs.”
from The Gait Guys……..“this is the problem with this study, and studies like it, particularly cadaver studies. There is no way to accurately assess the muscular forces and function at the joint. We have taken many hip labral tear and Rim syndrome patients and resolved their pain by looking at the muscular dysfunction that is leading to the Rim syndrome, impingement, tears etc…….. remember, an MRI is a static photo in a non-weightbearing state without muscular engagement. A rather useless test for this problem if you ask us. The information from the MRI’s regarding tissue pathology in the syndrome is nice and helpful, but you still have to fix the issues that allowed the problem to begin in the first place ! Repairing and debriding the labrum does not necessarily, and often does not, resolve the causative issues. Understanding normal gait and the implications of pathological gait patterns is paramount to fixing these issues. The tissue pathology is the tissue pathology, you still have to fix the problem that started the whole process ! ” …..The Gait Guys___________________________________________________________________________________
Study:Am J Sports Med. 2011 Jul;39 Suppl:92S-102S.
Strains across the acetabular labrum during hip motion: a cadaveric model.Safran MR, Giordano G, Lindsey DP, Gold GE, Rosenberg J, Zaffagnini S, Giori NJ.
Abstract“Background: Labral tears commonly cause disabling intra-articular hip pain and are commonly treated with hip arthroscopy. However, the function and role of the labrum are still unclear. Hypotheses: (1) Flexion, adduction, and internal rotation (a position clinically defined as the position for physical examination known as the impingement test) places greatest circumferential strain on the anterolateral labrum and posterior labrum; (2) extension with external rotation (a position clinically utilized during physical examination to assess for posterior impingement and for anterior instability) places significant circumferential strains on the anterior labrum; (3) abduction with external rotation during neutral flexion-extension (the position the extremity rests in when a patient lies supine) places the greatest load on the lateral labrum.Results: The posterior labrum had the greatest circumferential strains identified; the peak was in the flexed position, in adduction or neutral abduction-adduction. The greatest strains anteriorly were in flexion with adduction. The greatest strains anterolaterally were in full extension. External rotation had greater strains than neutral rotation and internal rotation. The greatest strains laterally were at 90° of flexion with abduction, and external or neutral rotation. In the impingement position, the anterolateral strain increased the most, while the posterior labrum showed decreased strain (greatest magnitude of strain change). When the hip is externally rotated and in neutral flexion-extension or fully extended, the posterior labrum has significantly increased strain, while the anterolateral labrum strain is decreased. Conclusion: These are the first comprehensive strain data (of circumferential strain) analyzing the whole hip labrum. For the intact labrum, the greatest strain change was at the posterior acetabulum, whereas clinically, acetabular labral tears occur most frequently anterolaterally or anteriorly. The results are consistent with the impingement test as an assessment of anterolateral acetabular labral stress. The hyperextension-rotation test, often used clinically to assess anterior hip instability and posterior impingement, did not show a change in strain anteriorly, but did reveal an increase in strain posteriorly. Clinical Relevance: Although this study does not include muscular forces across the hip joint, it does provide a clue as to the stresses about the labrum through the complete range of motions of the hip, which may help in providing a better understanding of the cause of labral tears and in the protection of labral repairs.”
Shawn and Ivo, ……… The Gait Nerds