G.H. Seeber1,2, M.P. Wilhelm3, P.S. Sizer Jr.2, A. Guthikonda4, A. Matthijs5, O.C. Matthijs5, D. Lazovic1, J.-M. Brismée2, K.K. Gilbert21University Hospital for Orthopaedics and Trauma Surgery Pius-Hospital, Medical Campus University of Oldenburg, Oldenburg, Germany, 2Center for Rehabilitation Research, Texas Tech University Health Sciences Center, Lubbock, United States, 3Tufts University School of Medicine, Medford, United States, 4Texas Tech University, Department of Kinesiology and Sports Management, Lubbock, United States, 5BOMA Physical Therapy Outpatient Clinic, Kapfenberg, AustriaBackground: Clinical stretching is frequently recommended for iliotibial band syndrome management. Current literature lacks conclusive findings regarding isolated iliotibial band tissue elongation and stiffness behaviors. Applying clinical-grade stretching force results to iliotibial band tissue behavior is thus challenging.Purpose: The purpose of this descriptive in vitro laboratory study is to determine isolated iliotibial band tissue tensile behaviors during tension-to-failure testing and to relate the results to previously reported iliotibial band stretch findings.Methods: Ten isolated un-embalmed iliotibial band specimens were exposed to tension-to-failure testing using a 10kN material testing system. Peak load, load at yield point, and ultimate failure load were measured in Newtons. Corresponding absolute (mm) and relative (%) tissue deformation was recorded. Load-deformation curves were established to calculate iliotibial band stiffness (N/mm).Results: A mean peak load of 872.8 ± 285.9N and resulting 9.0 ± 3.9% tissue deformation from initial length was recorded. An 805.5 ± 249.7N mean load at yield point and resulting 7.0 ± 1.9% tissue deformation was observed. A 727.6 ± 258.4N mean load was recorded directly prior to ultimate tissue failure. Mean tissue deformation at ultimate failure was 11.3 ± 4.2%. Mean iliotibial band system stiffness was 27.2 ± 4.5N/mm.Conclusion(s): The iliotibial band can withstand substantial tensile forces. Clinical stretching forces likely fall within the load-deformation curve elastic region and may not result in permanent iliotibial band tissue deformation. Sustained elongation resulting from stretching the ITB may require substantial patient compliance. Future studies should investigate potential underlying factors related to positive symptom relief from iliotibial band stretching that include immunological responses, fluid accumulation, altered proprioception, and pain perception.Implications: Although few earlier studies suggest that short-term clinical stretching unlikely results in appreciable iliotibial band tissue adaptation, stretching exercises to the iliotibial band are still the most frequently recommended management strategy to improve clinical symptoms, hip range of motion and subsequent lower extremity sensorimotor control during dynamic movements. It becomes clear on the basis of our study that the underlying mechanism of symptom improvement in ITBS after stretching is unlikely due to appreciable tissue adaptation but must be due to some other, yet unknown factor. Future investigations are necessary to understand the underlying mechanism behind this effect in order to treat patients with ITBS purposefully and thus avoid long standing impairments and/or recurrence of symptoms.Funding, acknowledgements: No funding has been received for this study.Keywords: Iliotibial band, Tensile behaviors, Load-to-failure testingTopic: Musculoskeletal: lower limbDid this work require ethics approval? NoInstitution: Texas Tech University Health Sciences Center (TTUHSC)Committee: Texas Tech University Health Sciences Center Anatomical Research CommitteeReason: Such cadaveric research did not require ITB approval at TTUHSC at the time of study conduction.All authors, affiliations and abstracts have been published as submitted.
Seeber et al. (Tue,) studied this question.