Multiple iliopsoas tendons: a cadaveric study and treatment implications for internal snapping hip syndrome

Benjamin Lin,Dimitris Challoumas,Vikas Khanduja,Jonathan Bartlett,Thomas D Lloyd,Cecilia Brassett

doi:10.1007/s00402-021-04009-5

Benjamin Lin, Dimitris Challoumas + Show 4 more

Open Access

https://doi.org/10.1007/s00402-021-04009-5

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Abstract

PurposeThis cadaveric study aimed at describing the anatomical variations of the iliopsoas complex.MethodsThe iliopsoas complex was dissected unilaterally in 28 formalin-embalmed cadavers—13 males and 15 females with a mean age of 85.6 years. The number, courses and widths of the iliacus and psoas major tendons were determined. Patients with previous hip surgery were excluded. The following measurements were taken from the mid-inguinal point: the distance to the point of union of the psoas major and iliacus tendon; and the distance to the most distal insertion of iliopsoas.ResultsThe presence of single, double and triple tendon insertions of iliopsoas were found in 12, 12 and 4 of the 28 specimens, respectively. When present, double and triple tendons inserted separately onto the lesser trochanter. The average length of the iliopsoas tendon from the mid-inguinal point to the most distal attachment at the lesser trochanter was 122.3 ± 13.0 mm. The iliacus muscle bulk merged with psoas major at an average distance of 24.9 ± 17.9 mm proximal to the mid-inguinal point. In all cases, the lateral-most fibres of iliacus yielded a non-tendinous, muscular insertion on to the anterior surface of the lesser trochanter and the femoral shaft, rather than joining onto the main iliopsoas tendon(s). The average total width of the psoas major tendon decreased with an increasing number of tendons: 14.6 ± 2.2 mm (single tendon), 8.2 ± 3.0 mm (2 tendons present) and 5.9 ± 1.1 mm (3 tendons present) (P < 0.001).ConclusionsThe results of this study suggest that multiple tendinous insertions of iliopsoas are present as an anatomical variant in more than 50% of the population. The non-tendinous muscular insertion of the iliopsoas on to the anterior surface of the lesser trochanter and femoral shaft found represents a novel anatomical variant not previously described.Level of evidenceLevel V

Highlights

In recent years, the iliopsoas muscle complex has gained increasing recognition as a generator of hip pain in internal snapping hip syndrome (ISHS) [1]
The most important finding of the present study was the high prevalence of multiple iliopsoas tendons
Of the 28 cadavers dissected in this study, over half were found to have multiple iliopsoas tendons, with two tendons in 12 subjects (43%) and three tendons in 4 (14%) subjects

Summary

Introduction

The iliopsoas muscle complex has gained increasing recognition as a generator of hip pain in internal snapping hip syndrome (ISHS) [1]. Initial management of ISHS is conservative— consisting of analgesia, physiotherapy and life-style modification—tenotomy may be indicated in cases of persistent debilitating pain [5, 6] This procedure, is only considered in the most severe cases due to previous findings of post-operative hip flexion weakness, atrophy of the remanent iliopsoas, and concerns regarding gross instability of the hip joint following iliopsoas tenotomy [5, 7,8,9]. A more detailed description of the anatomy of iliopsoas, its tendons and their insertions is of clinical significance in view of the causative role of this tendon complex in ISHS The purpose of this cadaveric study was, to describe the anatomical variations of the iliopsoas complex. We hypothesized that multiple tendons of iliopsoas are more common than single tendinous insertion

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