Andrew Franklyn-Miller Director of Research and Development at Sports Surgery Clinic LtdFollow
Feb 2, 2016
Some years ago, while working in the Anatomy laboratory of University of Melbourne with my colleague Dr Eanna Falvey, we carried out a 3 part study into the anatomy, and strain of the Iliotibial band, including an examination of the Obers Test used to assess its role in lateral knee pain in runners. I summarise the detail of the studies here and link to the original paper.
Subjects: 20 adult formalin fixed cadavers were examined (age: 79±12 years, height: 1.66±0.14m, body mass: 69.4±14.9 Kg) with University of Melbourne Human Ethics approval.
Methods: Limb alignment was assessed by measuring Q angle with <13° (male) and <18° (female) confirming a normal configuration. All limbs were fully flexed before positioning in the anatomical position. Deep dissection was performed to investigate the origin of ITB and the relationship to Tensae fascia latae (TFL), the location of the Gluteus Maximus insertion to ITB, the location of the longitudinal attachment of ITB to the linea aspera and the site of attachment of ITB to the lateral femoral condyle (LFC)
Findings: The ITB is in fact an integral part of the fascia of the leg, it is not a discrete structure. In all cases it was connected to the femur at the linea aspera from the greater trochanter by the intermuscular septum, to and including the lateral femoral condyle. We failed to demonstrate a bursae between the LFC and the ITB on a single cadaver. The TFL was completed enveloped in fascia its origins from the fascia latae of the iliac crest TFL inserting directly into ITB, behaving as an elongated tendon of TFL. A substantial portion of Gluteus maximus invests directly into ITB independent to the portion which invests to the greater trochanter. These findings are shown in cadaveric form in Fig.1
Fig 1. Dissected specimens of the iliotibial band on the left leg viewed posteriorly (A) The circumferential nature is demonstrated and the location of ITB. (B) The ITB is a lateral thickening of the fascia latae rather than a discrete entity.
(C) The fascia latae dissected to reveal the intermuscular septum separating vastus lateralis (VL) from Biceps femoris (BF)
Cadaveric ITB Strain
Subjects: Five un-embalmed fresh-frozen cadavers ( age: 76±10.0 year, height: 1.74±0.008 m, mass: 73.4±18.6 Kg). All cadavers were thawed for 36h at 4° before testing.
Protocol: The cadaver was positioned in the anatomical position. The three tests performed are shown in the diagram below. The hip was maintained in the anatomical position by applying load superior to the greater trochanter on the contralateral limb external loading was applied to the knee by the examiner to force hip adduction using a manual muscle tester at 100N. All stretches were held for 30s, separated by 1 minute intervals. All limbs were treated independently. Detached fascia specimens subjected to controlled loading showed little evidence of plastic deformation.
Methods: Insulated, 10mm, 120Ω foil type microstrain gauges (BCM Sensor technologies, Antwerp, Belgium) were attached to the external surface of the ITB using a gauge specific cryanocylate adhesive (TML, Tokyo, Japan). Data was acquired at 50Hz via a USB based CompactDAQ, The strain acquisition protocol has been published by the authors elsewhere. The sensor was located 8cm proximal to the lateral femoral condyle. The peak strain measured during each test was determined using a custom designed Labview analysis program (National Instruments, Austin Texas)
Data analysis : Multiple Wilcoxon signed rank tests at a significance of P<0.05 were performed for each combination (SPSS, Chicago, Ill USA). The microstrain (me) values [median(IQR)] for OBER [15.4(5.1-23.3)me], HIP [21.1(15.6-44.6)me], and SLR [9.4(5.1-10.7)]. Analysis showed the HIP stretch demonstrated greater strain than the other trials as seen in Fig 3.
Fig 3. Strain measured in the ITB during the three different testing protocols.
*Significant ( p<0.05) increase in strain during the HIP stretch in comparison with the SLR and OBER.
OBER;Obers Test, HIP hip flexion, adduction and external rotation;SLR, straight leg raise
Most of the traditional treatments for ITBS re based on the premise of a bursae between the ITB and the LFC, an ability to stretch the ITB, and the development of friction between the ITB and LFC due to transverse movement. Our findings challenge these anatomical and pathological finding’s. Two common treatments focus on distal ITB and the putative bursae. The effectiveness of these interventions due to the absence of bursae and the low magnitude and disparate strain occurring during stretching.
A third part of this study, not reported here examined the movement of the musculo- tendinous junction of tensae fascia latae during a maximal voluntary contraction in athletes. This demonstrates that the ITB stretches minimally in a MVC ( 0.2% increase in length), the cadaveric strain work demonstrates in the absence of muscle tone the stretches exert little influence on the length of ITB. This supports the tensioning role of Gluteus Maximus and Tensae fascia latae
The findings of these studies reported here highlight the limited role lengthening of the fascial component (ITB) has in lengthening the TFL/ITB complex which may instead result from a decrease in stiffness of the muscular components.
So we can see that endlessly foam rolling the ITB can not only irritate the fat pad but compresses Vastus lateralis. Focussed soft tissue release should be directed at TFL and Gluteus Medius which act as a direct tensioning to the fascia but no role in the 'release' of the fascial band itself, which is adherent via a fascial investment to the femur along its length.
Source: Scand J Med Sci Sports. 2010 Aug;20(4):580-7. Iliotibial band syndrome: an examination of the evidence behind a number of treatment options