Table 4.
Specific data from biomechanics studies included in the review
| Author | Journal | Type of article | Biomechanics evaluation | Number of specimens | ILFL biomechanics |
|---|---|---|---|---|---|
| Joint function | |||||
| Schleifenbaum et al 201617 | Journal of Biomechanics | Controlled laboratory study | Stress–strain data of ILFL, ISFL and PFL were obtained from cadavers using a highly standardized setting. Maximum strains were compared to the distances required for dislocation. | 21 (40 hips; age 14–93 years) | The mean elastic modulus was 24.42±1.0 N/mm2 for the ILFL Maximum strain was 84.5±36.0% The elastic modulus was higher in the young group than in the old group (31.0±22.5 vs. 18.3±17.9 N/mm2) Ultimate stress was higher in the young than in the old (13.1 ±9.1% vs. 7.1±4.7%). |
| Pieroh et al 20162 | PloS One | Controlled laboratory study | Uniaxial stress–strain properties were obtained from the load-deformation curves before the secant elastic modulus was computed. Strain, elastic modulus and cross sections were compared. |
17 (12 hips; 83.65 ± 10.54 years) | ILFL: Cross-sectional area of 53.5±15.mm2 Mean strain: 129.8±11.1% Elastic moduli: 48.8±21.4 N/mm2 |
| Martin et al 200818 | Arthroscopy | Controlled laboratory study | The motion at the hip joint was measured in internal and external rotation through ranges of motion from 30° flexion to 10° extension along a neutral swing path. The motion was standardized by use of frame stabilization and motion tracking. |
12 hips (mean 62 years) | The release of the MILFL and LILFL each gave the greatest increase of motion in external rotation, with the LILFL release providing more range of motion in flexion and in a neutral position. The LIFL release also showed a significant motion increase in internal rotation, primarily in extension. |
| van Arkel et al 201519 | Bone Joint J | Controlled laboratory study | The hip was rotated throughout a complete ROM and the contributions of the MILFL and LILFL, PFL and ISFL and the LT to rotational restraint was determined by resecting a ligament and measuring the reduced torque required to achieve the same angular position as before resection. |
9 (18 hips; age 61–89 years) | The ILFL provided primary external rotation restraint in all hip positions, and both primary internal and external rotation restraint when the hip was extended or in neutral hip flexion. The MILFL dominated in neutral flexion or extension, and the lateral arm in all other positions. |
| Hidaka et al 201420 | Clin Anatomy | Controlled laboratory study | Clinically available stretching positions for ligaments were adopted. Strain on each ligament was measured by a displacement sensor during passive torque to the hip joint. Hip motion was measured using an electromagnetic tracking device. The strained ligaments were captured on clear photographs. | 8 (age 81–98 years) | Strain (%) SBILFL: Extension: 0.30±0.53; Add 0.86±1.60; ER 3.48±2.57; Extension 10° + ER: 0.74±1.29; Add 10° + ER 2.58±3.53 IBILFL: Extension: 1.86±1.22; Add 0.0±0.0; ER 0.65±1.27; Er 10° + Ext: 1.46±0.85; ER 20° + Ext 1.25±0.63; ER 30° + Ext: 0.57±0.56 |
| Hidaka et al 200921 | Manual Therapy | Controlled laboratory study | Strains on the SBILFL and IBILFL were measured using a displacement sensor, and the range of movement of the hip joints was recorded using a 3Space Magnetic Sensor. Reference length (L0) for each ligament was determined to measure strain on the ligaments. | 8 hips (age 67–91 years) | Strain SBILFL: add 10° with maximal ER: 3.2±3.3%; Add 20° with maximal ER: 4.0±4.2%; maximal ER 3.7±3.0% IBILFL: maximal extension: 2.1±2.1%; maximal extension and 20° ER: 1.8±2.1% |
| Ito et al 200922 | J Orthop Res | Controlled laboratory study | Each specimen was tested at a neutral hip position of 0° flexion, 0° abduction, and 0° internal rotation. Tensile force was applied parallel to the longitudinal axis of the femoral shaft. After 10 cycles of preconditioning from 20 to 100 N at a distraction rate 0.4 mm/s, each specimen was loaded in tension by distracting the femur longitudinally from the acetabulum at a constant rate of 0.4 mm/s to a displacement of 5 mm. The applied tensile load and crosshead displacement were recorded at time intervals of 0.01 s. |
7 (age 59–85 years) | With the distraction load in the normal condition defined as 100%, the load required to cause 3-mm joint displacement was reduced to 82% after incising the ILFL. The distraction load did not significantly decrease after the ILFL was incised compared to just venting the capsule. |
| Bakshi et al 201724 | Orthop J Sports Med | Controlled laboratory study | 5 different tests: intact capsule, intact labrum (all intact); sutured capsule, intact labrum (sutured intact); sutured capsule, 1-cm partial labrectomy (sutured labrectomy); partial capsulectomy, 1-cm partial labrectomy (partial capsulectomy); and total capsulectomy, 1-cm partial labrectomy (total capsulectomy). Each hip was tested in a neutral position with a 20-N compressive force. The load at 12 mm of anterior translation was recorded for each state after 2 preconditioning trials. |
8 (16 hips; age 29–64 years) | ILFL plays a primary role in anterior hip stability in the labral-injured state providing a restraint to anterior translation when the stabilizing effect of the labrum has been lost. |
| Myers et al 201123 | Am J Sports Med | Controlled laboratory study | Each specimen was selectively skeletonized down to the hip capsule. Four tantalum beads were embedded into each femur and pelvis to accurately measure hip translations and rotations using biplane fluoroscopy while either a standardized 5 N_m external or internal rotation torque was applied. The hips were tested in 4 hip flexion angles (10° of extension, neutral, and 10° and 40° of flexion) in the intact state and then by sectioning and later repairing the acetabular labrum and ILFL in a randomized order. |
8 (16 hips; age 53–68 years) | External rotation significantly increased by 12.9°±5.2° after sectioning of the iliofemoral ligament alone (54.4°±6.6°). External rotation significantly increased by 7.1°±5.9° from the ILFL-alone sectioned condition (54.4°±6.6°) to when both the labrum and ILFL were sectioned in the both-sectioned condition. When only the ILFL was repaired (42.5°±6.1°) compared with the both-sectioned condition (61.5°±5.7°), a significant decrease in external rotation of 19.0° was found sectioned ILFL alone resulting in significantly greater anterior translation of the femur. |
| Kivlan et al 201915 | Int J Sports Phys Ther | Exploratory cohort study with good reference standards | A string model representing the medial and lateral arms of the ILFL ligament was secured to the proximal and distal attachment points. The amount of length change of the string model was compared in four test positions: 1) external rotation, 2) hyperextension-external rotation 3) abduction-extension-external rotation, and 4) adduction-extension- external rotation. |
9 (12 hips; age 57–84 years) | For the MILFL, the greatest change occurred in the adduction-extension-external rotation position (12.7 mm). This was significantly greater than the external rotation (5.1 mm; p = 0.002) and abduction-extension-external rotation position (1.9 mm; p < 0.001). The LILFL also had the greatest excursion in the adduction-extension-external rotation position (16.6 mm). This length change was significantly greater than the external rotation position (8.6 mm; p = 0.002), the hyperextension-external rotation (11.1 mm; p = 0.047), and the abduction-extension-external rotation position (5.6 mm; p < 0.001). |
| Burkhart et al 202025 | Knee Surg Sports Traumatol Arthrosc | Controlled laboratory study | Each specimen was tested at five passive hip flexion angles (15° of extension [−15°], 0°, 30°, 60°, and 90°). At each flexion angle, a baseline scan was taken where a 10 N axial load was applied with all other load axes set to 0 N and 0 Nm. | 7 hips; age 78.3±6.0 | SBILFL: There was a significant flexion angle by loading type interaction with respect to the SBILFL. The application of IR increased the relaxation of the ligament across all tested positions with significantly less strain in the ligament at 30° and 60° compared with 0°. The strains were significantly different between IR and ER at all flexion angles. IBILFL: There was a significant flexion angle by loading type interaction for the IBILFL; however, pairwise differences could not identify differences for either IR or ER. Qualitatively, however, the application of an IR reduced the strains in the IBILFL across all tested positions, while the application of an ER increased the strains in the IIFL across hip flexion angles. Strains were significantly different between IR and ER at all flexion angles. |
Note. ILFL, iliofemoral ligament; LILFL, lateral arm of the iliofemoral ligament; MILFL, medial arm of the iliofemoral ligament; ISFL, ischiofemoral ligament; PFL, puboferamoral ligament; IBILFL, inferior band of the iliofemoral; SBILFL, superior band of the iliofemoral ligament; LT, ligamentum teres; ROM, range of motion; ER, external rotation; IR, internal rotation.