Cross-sectional analysis of the iliopsoas tendon and its relationship to the acetabular labrum: an anatomic study.
BACKGROUND
Hip pain in patients with normal bony anatomy and anterior labral injury may be related to compression of the iliopsoas tendon across the anterior capsulolabral complex. No attempts to characterize the 3-dimensional anatomy of the iliopsoas tendon and its relationship to the acetabular labrum have been reported to date.


OBJECTIVE
The iliopsoas tendon directly overlies the capsulolabral complex. Contribution of the muscle belly and tendon to the overall circumference at the level of the labrum is approximately the same.


METHODS
Descriptive laboratory study.


METHODS
Eight hip joints were dissected and cross-sectional measurements of the iliopsoas muscle-tendon complex were performed using digital calipers and image analysis software.


RESULTS
The iliopsoas tendon in all specimens was located directly anterior to the anterosuperior capsulolabral complex at the 2 to 3 o'clock position. The overall length of the iliopsoas tendon from the lesser trochanter to the acetabular labrum was 75.4 +/- 0.9 mm. The circumference of the iliopsoas tendon at the lesser trochanter was 25.5 +/- 2.6 mm, the iliopsoas tendon at the level of the labrum was 28.4 +/- 2.8 mm, and the iliopsoas tendon-muscle belly complex at the level of the labrum was 63.8 +/- 7.4 mm. At the level of the labrum, the iliopsoas is composed of 44.5% tendon and 55.5% muscle belly.


CONCLUSIONS
The close anatomic relationship of the iliopsoas tendon to the anterior capsulolabral complex suggests that iliopsoas pathologic changes at this level may lead to labral injury. Additionally, these data suggest that at the level of the labrum, 45% of the tendon-muscle belly complex should be released to release the entire tendinous portion.


CONCLUSIONS
Knowledge of the cross-sectional anatomy of the iliopsoas tendon and its relationship to the acetabular labrum will better assist surgeons in treating lesions associated with iliopsoas injury.
Department of Orthopaedic Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Joshua M
JM
Alpert
Michal
M
Kozanek
Guoan
G
Li
Bryan T
BT
Kelly
Peter D
PD
Asnis
D000076:Acetabularia; D000077:Acetabulum / Q000033:anatomy & histology*; D019412:Anatomy, Cross-Sectional; D001182:Arthroscopy; D006621:Hip Joint / Q000033:anatomy & histology; D006801:Humans; D018482:Muscle, Skeletal / Q000033:anatomy & histology; D016658:Psoas Muscles / Q000033:anatomy & histology*; D013710:Tendons / Q000033:anatomy & histology*