Paper #74 - ISHA Annual Scientific Meeting 2016

Assessment of the Severity of Muscle Atrophy that Occurs After Arthroscopic Labral-Level and Lesser Trochanteric Iliopsoas Tenotomies

Brian E. Walczak, MD, Madison, WI UNITED STATES
James S. Keene, MD, Madison, WI UNITED STATES

University of Wisconsin, Madison, WI, UNITED STATES

FDA Status Not Applicable

Summary: Both lesser trochanteric (LT) and labral-level (LL) arthroscopic iliopsoas (IP) tenotomies cause iliacus and psoas muscle atrophy, but in LT patients it’s more severe and associated with chronic IP tendon disruption and adjacent (e.g. gluteus) muscle atrophy.

Abstract:
Introduction: Iliopsoas (IP) muscle atrophy is a known consequence of open iliopsoas tenotomies, but the severity and significance of the muscle IP atrophy after arthroscopic labral-level and lesser-trochanteric iliopsoas tenotomies has not been determined. This study quantified the amount of muscle atrophy that occurred in 48 patients after arthroscopic iliopsoas tenotomies that were performed for treatment of snapping and/or impingement of the tendon.
Methods: From the senior author’s data base of 1285 hip arthroscopies, forty-eight patients who had MRI’s obtained 6 months to 5 years after arthroscopic labral-level (28 LL patients) or lesser trochanteric (20 LT patients) iliopsoas tenotomies are the basis of this report. The pre- and postoperative MRI’s of each patient were examined independently by three musculoskeletal radiologists who graded the postoperative muscle atrophy from 0 (no fatty infiltration) to 4 (>75% fatty infiltration) and noted any compensatory muscle hypertrophy or abnormal IP tendon morphology (Figure 1).
Results: The postoperative MRI’s were performed for recurrent hip pain and subsequent MRI diagnoses were progressive chondrosis in 34 patients (70%) and recurrent labral tear in 19 patients (40%). Average time from surgery to the postoperative MRI was 1.7 years (range 6 months-5 years), and none of the patients had iliacus or psoas muscle atrophy on their preoperative MRI’s. In contrast, 89% (25/28) of the labral-level patients (LL Group) and 90% (18/20) of the lesser-troch-release patients (LT Group) had muscle atrophy on their postoperative MRI’s. Although the incidence of atrophy was similar in both groups, the severity of atrophy was much greater in the LT Group where 11 patients (55%) had grade 4 IP atrophy and 3 patients (15%) had grade 0-1 atrophy (Table 1). The LL Group had only 2 patients (7%) with grade 4 atrophy and 18 (61%) with grade 0-1 atrophy; these differences were significant. The postoperative MRI’s of the LT patients also demonstrated atrophy in the gluteus maximus (30%), the quadratus femoris and rectus femoris (10%), and vastus lateralis (5%) muscles, and 35% had disruption of the iliopsoas tendon. In contrast, none of the LL patients had postoperative MRI evidence of atrophy in any these muscles or disruption of their IP tendon.
Conclusions: Most patients develop iliopsoas muscle atrophy after arthroscopic labral-level (89%) and lesser trochanteric (90%) IP tenotomies. However, grade 4 atrophy was significantly more common (55% vs. 7%, p = 0.01) in LT patients and was evident on MRI’s obtained five years after their tenotomies. In addition, 30% of the LT patients also developed atrophy of the gluteus maximus, and 35% had a gap in their IP tendon ? 9 months after their tenotomy. In contrast, none of the LL patients had postoperative MRI evidence of atrophy in any of the adjacent muscles or disruption of their IP tendon. Both lesser trochanteric and labral-level arthroscopic iliopsoas tenotomies cause iliacus and psoas muscle atrophy, but in LT patients it’s more severe and associated with chronic IP tendon disruption and adjacent (e.g. gluteus) muscle atrophy.