Anatomic variance of the iliopsoas tendon.
BACKGROUND
The iliopsoas tendon has been implicated as a generator of hip pain and a cause of labral injury due to impingement. Arthroscopic release of the iliopsoas tendon has become a preferred treatment for internal snapping hips. Traditionally, the iliopsoas tendon has been considered the conjoint tendon of the psoas major and iliacus muscles, although anatomic variance has been reported.


OBJECTIVE
The iliopsoas tendon consists of 2 discrete tendons in the majority of cases, arising from both the psoas major and iliacus muscles.


METHODS
Descriptive laboratory study.


METHODS
Fifty-three nonmatched, fresh-frozen, cadaveric hemipelvis specimens (average age, 62 years; range, 47-70 years; 29 male and 24 female) were used in this study. The iliopsoas muscle was exposed via a Smith-Petersen approach. A transverse incision across the entire iliopsoas musculotendinous unit was made at the level of the hip joint. Each distinctly identifiable tendon was recorded, and the distance from the lesser trochanter was recorded.


RESULTS
The prevalence of a single-, double-, and triple-banded iliopsoas tendon was 28.3%, 64.2%, and 7.5%, respectively. The psoas major tendon was consistently the most medial tendinous structure, and the primary iliacus tendon was found immediately lateral to the psoas major tendon within the belly of the iliacus muscle. When present, an accessory iliacus tendon was located adjacent to the primary iliacus tendon, lateral to the primary iliacus tendon.


CONCLUSIONS
Once considered a rare anatomic variant, the finding of ≥2 distinct tendinous components to the iliacus and psoas major muscle groups is an important discovery. It is essential to be cognizant of the possibility that more than 1 tendon may exist to ensure complete release during endoscopy.


CONCLUSIONS
Arthroscopic release of the iliopsoas tendon is a well-accepted surgical treatment for iliopsoas impingement. The most widely used site for tendon release is at the level of the anterior hip joint. The findings of this novel cadaveric anatomy study suggest that surgeons should be mindful that more than 1 tendon may be present and require release for curative treatment.
Marc J. Philippon, Steadman Philippon Research Institute, 181 West Meadow Drive, Suite 1000, Vail, CO 81657, USA. mjp@sprivail.org.
Marc J
MJ
Philippon
Brian M
BM
Devitt
Kevin J
KJ
Campbell
Max P
MP
Michalski
Chris
C
Espinoza
Coen A
CA
Wijdicks
Robert F
RF
Laprade
D000368:Aged; D000369:Aged, 80 and over; D001182:Arthroscopy; D002102:Cadaver; D004210:Dissection; D005260:Female; D006621:Hip Joint / Q000033:anatomy & histology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016658:Psoas Muscles / Q000033:anatomy & histology*; D013710:Tendons / Q000033:anatomy & histology*
anatomic variance; hip arthroscopic surgery; iliopsoas; labral tears; tenotomy