Monday, July 8, 2013

Iliopsoas Impingement as a Unique Cause of Hip Labral Tears

We know that bony lesions of the femoral head-neck junction (CAM impingement) and of the hip socket (pincer impingement) can cause labral tears. We also know that impingement of the iliopsoas tendon on the acetabular labrum is fairly common in patients with hip impingement (femoroacetabular impingement, FAI). Therefore a partial release, or tenotomy, of the psoas tendon is often performed during hip arthroscopy. Some physicians now say that, in some cases, psoas impingement in itself – without bony impingement – may be the cause of tears of the labrum.

Three doctors at three different hip centers reviewed 700 hip arthroscopies after the fact. They included young athletes, age 12-25, who presented with labrum tears from the two to three o’clock position. Athletes who had osteoarthritis, crossover sign (line of the anterior and posterior walls cross over each other), coxa profunda (deep hip sockets), CAM lesion, pincer lesions, acute trauma or coxa saltans (snapping hip) and/or significant hip laxity were excluded. In other words, patients who “shouldn’t” have labral tears were included in the study.

Out of 26 hips (22 patients) that were identified with a labrum tear apparently caused by psoas impingement (there were no other hip abnormalities), all but one were female. The labrum had been repaired with anchors in all but two patients. The psoas tendon was released in all patients at the level of the capsule. (In A Patient’s Guide to Hip Impingement you can read more about psoas tenotomy, the different ways it can be done and what the research says about who is a good candidate.)The average Harris Hip Score (HHS) improved from 70 to pre-op to 94 (postop), and there were no complications.

So what would the difference be between a labral tear caused by hip impingement (FAI) and a labral tear caused by psoas impingement? When you move the hip from flexion to extension, the iliopsoas tendon moves over the femoral head. When snapping is present from psoas impingement, it is mostly the back and forth motion over the femoral head that causes the snapping sound. Labral tears with FAI are typically found from the 10 to 2 o’clock position.

However, doctors have also noticed tears more medially (towards midline of body), especially during revision arthroscopy. The tears that have been found more medial are also located next to the iliopsoas tendon, separated only by the joint capsule. Therefore some have theorized that the psoas tendon can put pressure on, and rub against, the more medial labrum, causing tears of the labrum and painful, impairing psoas inflammation. That is the reason that the study only included patients with 3 o’clock (more medial) labral tears.

The study authors concluded that internal snapping hip (coxa saltans interna) has been implicated as a source of pain particularly in young women, but labral pathology has not previously been described together with snapping hip. The authors found it likely that the repetitive snapping of the psoas tendon could cause labral tears in the more medial position. However, the doctors sought to exclude patients who reported loud snapping. That way they were also able to conclude that psoas impingement might even be considered as a silent or non-snapping coxa saltans.

Finally, the doctors suggested that leaving the more medial labrum tears, or psoas impingement lesion, untreated could be a potential source of continuing hip pain and a failed first hip arthroscopy. Recognizing labrum tears due to psoas impingement as a unique cause of hip pain that requires unique treatment could improve patient outcomes and decrease revision surgeries.

Source: Psoas Impingement Causing Labrum Tear: A Series From Three Tertiary Hip Arthroscopy Centers. Journal of the Louisiana State Medical Society. Vol. 165 March/April 2013. Brett M. Cascio, MD; David Kind, MD; Yi-Meng Yen, MD, PhD.

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