Artikel
The relation of the rectus femoris muscle to the iliocapsularis muscle – Differences between dysplastic and overcovered hips
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Veröffentlicht: | 23. Oktober 2013 |
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Gliederung
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Introduction: The iliocapsularis muscle is covering the anterior part of the hip capsule. Compared to hips with acetabular overcoverage it is hypertrophied in dysplastic hips. Thus it may be used as an adjunct for decision making in the therapy for hip dysplasia or femoroacetabular impingement. To verify iliocapsular hypertrophy without time consuming measurements it would be suitable to have a nearby reference point for visual comparison. We postulated that the rectus femoris muscle qualifies for this task.
Question: Is the relation between the rectus femoris muscle and the iliocapsularis muscle different in dysplastic and overcovered hips?
Methods: On MR-arthrography of 45 patients with dysplastic hips (group A) and 40 patients with acetabular overcoverage (group B) we measured the cross-sectional area (CSA), circumference, height and width of the iliocapsularis muscle and of the rectus femoris muscule too. Then we calculated the relation of these parameters between group A and B.
Results: The measured parameters were normally distributed, statistical analysis was therefore performed with students t-test. The relation between group A and B was significantly different (<0.001) for all measured parameters (CSA, circumference, height and width). With a cutoff of 0.9 for the CSA ratio (iliocapsularis at least 10% bigger than the rectus femoris muscle) there was a sensitivity of 62% and a specificity of 100% to detect a dysplastic hip correctly. EbM-Level 3.
Conclusion: The relation of the rectus femoris muscle to the iliocapsularis muscle differs highly significant in dysplastic and overcovered hips respectively. Therefore it may be suitable to diagnose iliocapsular hypertrophy in reference to the rectus femoris muscle. This visible comparison of the two muscles without detailed and time consuming measurements may be practical in the daily routine since iliocapsularis hypertrophy was proposed as an adjunct in decision making for the treatment of borderline dysplastic hips.