Fig 1.
(a) Custom-built opto-mechanical characterisation device, (b) Excised flat capsule specimen attached to 22 pneumatic actuators using the double hook gripping method and monofilament suture lines. Scale bars indicate a length of 25 mm.
Fig 2.
(a) Anterior and (b) posterior views of the hip joint capsule complex.
The commonly identified ligaments are highlighted. Black dashed line denotes circumferential incision lines on acetabular and femoral insertions. Red and green lines denote two incisions to detach the capsule longitudinally; between greater trochanter and the anterior superior iliac spine (green); between lesser trochanter (LT) and pubofemoral ligament (red).
Fig 3.
A process flow of fibrous structure identification following opto-mechanical characterisation of the tissue.
Table 1.
The mean cross-sectional area (± SD) of hip capsular ligaments.
Fig 4.
(a) Image of detected fibrous structure network (represented by red contour) of human hip joint capsule revealing seven ligamentous structures (Image is a stack of n = 9 measured hip capsules), (b) Anterior view of fibrous network reconstructed onto right hip joint anatomy, (c) Inferior view of fibrous network reconstructed onto right hip joint anatomy.
AIIS, Anterior Inferior Iliac Spine; GT, Greater Trochanter; LT, Lesser Trochanter. The colour scale represents the presence of fibrous structures across the stacked capsule, red representing regions with fibrous structures detected across all capsules and black representing regions detected with no fibrous structures in any capsule. Numbering corresponds to the probability density histograms shown in Fig 5, which were used to identify the ligaments and their orientation. Scale bars indicate a length of 25 mm.
Fig 5.
Ligamentous structures detected from probability density histograms of fibre bundle orientation, relative to Llong axis.
Numbering corresponds to structures denoted in Fig 4.
Fig 6.
The mean ligament stress versus stretch for identified ligaments in the hip capsule.
(n = 9 per ligament, the error bars are standard deviation). IFL, iliofemoral ligament; PFL, pubofemoral ligament; ISFL, ischiofemoral ligament; ZO, zona orbicularis.
Fig 7.
The mean tangent modulus with standard deviation for identified ligaments in the hip capsule extracted in a single test by application of a homogeneous biaxial stress distribution.
(n = 9 per ligament). Statistical significance is indicated as follows: * p ≤ 0.05, ** p ≤ 0.01. IFL, iliofemoral ligament; PFL, pubofemoral ligament; ISFL, ischiofemoral ligament; ZO, zona orbicularis.