title: MR Appearance and Clinical Significance of Changes in the Hip Muscles and Iliopsoas Tendon After Arthroscopic Iliopsoas Tenotomy in Symptomatic Patients.
abstract: BACKGROUND
  Iliopsoas tenotomy is a treatment for snapping hip. Does this surgical procedure change the surrounding muscle and tendon anatomy?
  
  
  OBJECTIVE
  This study seeks to evaluate the changes in the MR appearance of the hip muscles and iliopsoas tendon in patients following arthroscopic iliopsoas tenotomy.
  
  
  METHODS
  One hundred sixty-nine consecutive adults were evaluated after iliopsoas tenotomy at the lesser trochanter. Each MR exam was evaluated independently by three radiologists for muscle edema, atrophy (grade 0-4), compensatory hypertrophy, signal within the iliopsoas tendon (increased on T1 or T2 sequences), and iliopsoas tendon morphology (distorted or disrupted) above, at, and below the iliopectineal eminence. A finding was considered positive if reported by two or three of the radiologists.
  
  
  RESULTS
  Twenty subjects met the inclusion criteria. Muscle edema was present in 15% (3/20) of subjects within the iliacus, psoas, and quadratus femoris. Atrophy was observed in the following muscles: iliacus 85% (17/20), psoas 75% (15/20), quadratus femoris 10% (2/20), rectus femoris 5% (1/20), vastus lateralis 5% (1/20), and gluteus maximus 25% (5/20). There was no compensatory hypertrophy. Ninety percent (18/20) had increased T1 and 10% (2/20) had increased T2 signal within the iliopsoas tendon. Thirty-five percent (7/20) of the iliopsoas tendons was disrupted and 85% (17/20) was distorted, most commonly below the iliopectineal eminence.
  
  
  CONCLUSIONS
  The majority of postoperative symptomatic patients has atrophy of the iliacus and psoas muscles and distortion and disruption of the iliopsoas tendon and should be recognized as a normal imaging appearance following iliopsoas tendon release.
authors.affiliation: Department of Radiology, University of Wisconsin, 600 Highland Avenue, Madison, WI 53705 USA.
authors.forename: Kendra S
authors.initials: KS
authors.lastname: Hain
authors.affiliation: Department of Radiology, University of Wisconsin, 600 Highland Avenue, Madison, WI 53705 USA.
authors.forename: Donna G
authors.initials: DG
authors.lastname: Blankenbaker
authors.affiliation: Department of Radiology, University of Wisconsin, 600 Highland Avenue, Madison, WI 53705 USA.
authors.forename: Arthur A
authors.initials: AA
authors.lastname: De Smet
authors.affiliation: Department of Orthopedics, University of Wisconsin, 600 Highland Avenue, Madison, WI 53705 USA.
authors.forename: James S
authors.initials: JS
authors.lastname: Keene
authors.affiliation: Department of Radiology, University of Wisconsin, 600 Highland Avenue, Madison, WI 53705 USA.
authors.forename: Alejandro Munoz
authors.initials: AM
authors.lastname: Del Rio
keywords: iliopsoas; muscle atrophy postoperative; tenotomy