The role of iliocapsularis in hip pathology: a scoping review

Abstract

The iliocapsularis is a relatively unheard-of muscle, located deep in the hip covering the anteromedial capsule of the hip joint. Little is known about this constant muscle despite its clinical relevance. The aims of this scoping review are to collate the various research studies reporting on the detailed anatomy and function of iliocapsularis and to demonstrate how inter-individual differences in iliocapsularis can be used as a clinical adjunct in guiding diagnosis and treatment of certain hip joint pathologies. A computer-assisted literature search was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Our review found 13 studies including 384 cases meeting our inclusion criteria. About 53.8% of the studies involved human cadavers. The current scoping review indicates the relevant anatomy of the iliocapsularis, being a small muscle which arises from the inferior border of the anterior inferior iliac spine and anteromedial capsule of the hip joint, inserting distal to the lesser trochanter. Therefore, based upon these anatomical attachments, iliocapsularis acts as a dynamic stabilizer by tightening the anterior capsule of the hip joint. Implications of this association may be that the muscle is hypertrophied in dysplastic or unstable hips. Determining the size of the iliocapsularis could be of conceivable use in patients with hip symptoms featuring signs of both borderline hip dysplasia and subtle cam-type deformities. Although future research is warranted, this study will aid physicians to understand the clinical importance of the iliocapsularis.

The anterior hip capsule is thinner in dysplastic hips: a study comparing different young adult hip patients

“…An intact ligamentum teres was also found to be a predictor of a relatively low risk of instability [20]. The hypertrophy of extracapsular iliocapsular muscle was considered to be a secondary sign of hip dysplasia [33]. However, very few studies have focused on the morphological features of the capsule, which prompted us to undertake this study.…”

“…[24]. The previous investigation on the morphology of soft tissue around the hip joint only revealed that hypertrophy of labrum and iliocapsularis muscle could be related to hip instability [29, 33]. However, knowledge gaps exist about the relationship between the capsular morphology and the instability of the hip joint.…”

Iliocapsularis: An exploration of the muscle and its omission in education

“…These exclusions resulted in 28 PRL articles which included the ICm. Of the 28 publications mentioning the ICm, 19 highlighted the morphology and proposed functional roles of the muscle (Babst et al, 2011;Baker et al, 2022;Das & Singh, 1950;Elvan et al, 2019;Haefeli et al, 2015;Hammoud et al, 2014;Keet et al, 2021;Konno et al, 2021;Lawrenson et al, 2017Lawrenson et al, , 2019Lawrenson et al, , 2020Philippon et al, 2014;Pourcho et al, 2015;Retchford et al, 2013;Ricci & Özçakar, 2019;Saito et al, 2021;Walters et al, 2014;Wang et al, 2021;Ward et al, 2000). Nine additional studies reported the presence of the ICm using clinical scenarios consisting of surgical interventions and diagnostic imaging (Agten et al, 2016;Camenzind et al, 2018;Fagotti et al, 2020;Harris, 2016;Kalhor et al, 2021;Siebenrock et al, 2015;Spiker et al, 2021;Wyatt et al, 2017;Xu et al, 2021).…”