Hip Biomechanics OHL.pdf

Unit 5. The Hip Human Biomechanics Prof. Olga Hoyos Lopez MSc PT  Hip Joint/Femoroacetabular joint -Synovial ”Ball and socket” joint / spheroidal joint -3dg freedom: Flex/Ext, ABD/ADD, IR/ER FUNCTION: Support load of head, arms & trunk Force transmission Locomotion...

Unit 5. The Hip Human Biomechanics Prof. Olga Hoyos Lopez MSc PT  Hip Joint/Femoroacetabular joint -Synovial ”Ball and socket” joint / spheroidal joint -3dg freedom: Flex/Ext, ABD/ADD, IR/ER FUNCTION: Support load of head, arms & trunk Force transmission Locomotion Works in Non-weight bearing (NWB) during Open Kinematic Chain (OKC) movements, and also in Weight bearing (WB) during Closed Kinematic Chain (CKC) movements 2 Anatomical reminder: Pelvis -2 coxa or innominate bones -Each inominate is composed of 3 fused bones: Pubis Ilium Ishium -Articulating surface in the hip joint: acetabulum. Acetabulum is part of the pelvis 3 Acetabulum Head of the femur articulates with the acetabulum Acetabulum is normally directed laterally, anteriorly and inferiorly This creates the Hip Joint ( spheroid joint) Acetabular labrum- increases congruence(stability) Transverse acetabular ligament: techni- cally part of the labrum, but contains no chondrocytes 4 Anatomical Variations and influence in the movement The angle of inclination between the neck and the shaft of the femur can vary between humans. A) Normal 120-125º B) Coxa Vara 105º C) Coxa Valga 140º The changes in the angle of inclination of the head of the femur can influence movement 5 Hip joint stability One of the most stable synovial joints! Static stabilizers (Passive structures): – Acetabular Labrum (Fibrocartilage) & transverse acetabular ligament – Strong capsule. Major contributer to stability – Ligaments: Iliofemoral Pubofemoral Ischiofemoral Ligamentum Teres Dynamic stabilizers: muscles and myofascial tissue 6 Hip joint stability – Acetabular Labrum (Fibrocartilage) Wedge-shaped fibrocartilage Serves to deepen the socket and increases the concavity of the acetabulum. Hip joint more stable than shoulder joint due to depth of the acetabulum 7 Hip joint stability: *Ligamentum teres -Directly connects head of femur to acetabulum. -Also called “ligament of head of femur” or “ligamentum femoris capitis” -Provides stability, propioception & coordination. -Important vascular supply to hip. Also involved in nociception 8 Contact area of the hip joint during the gait cycle 9 Osteokinematics of the hip 10 Arthrokinematics of the hip Open kinetic Chain (NWB). Femoral head moves on acetabulum. Femur=CONVEX Roll&glide: opposite directions! Flexion: femur spins posterior Extension: femur spins anterior – Flexion-extension (flexion:PPT extension:APT) 11  Kinetics of Flexion: Miology Anterior Muscles Psoas/illiacus Rectus Femoris Sartorius TFL 12 Kinetics of the Extension Myology Posterior Muscles Gluteus Maximus Gluteus Medius, Gluteus Minimus Piriformis Semitendinosus Semimembranosus Biceps femoris 13  Limits for Flexion and Extension Limits of Flexion. -Knee in Extension: posterior chain soft tissue tension -Knee in Flexion: structural-hit of the knee with the chest. Limits of Extension -Iliofemoral ligament -Anterior chain soft tissue tension 14 Arthrokinematics of the hip Open kinetic Chain (NWB). Femoral head moves on acetabulum. Femur=CONVEX Roll&glide: opposite directions! Abduction-adduction ABDUCTION: Femur Rolls superior/glides inferior ADDUCTION: Femur Rolls inferior/glide superior 15  Limits for Abduction and Adduction Limits of Abduction -Soft tissue tension from adductor muscles -Pubofemoral and Iliofemoral ligaments -Articular limitation Limits for Adduction -Iliofemoral Ligament 16  Kinetics of Hip Abduction Sagittal plane determines muscle function. Primary motor muscles -Gluteus Medius -Tensor of the Fasciae Latae (TFL) Secondary motor muscles -Gluteus minimus -Piriformis -Gluteus Maximus fibers -Obturator Externus and Gemellius superior and inferior -Sartorius 17  Kinetics of Hip Adduction Sagittal Plane determines function Primary motor muscles – Adductor Magnus – Aductor Longus – Adductor Brevis – Gracilis Secondary motor muscles – Quadratus Femoris – Obturator Externus and Obturator Internus 18 Arthrokinematics of the hip Open Kinetic Chain (NWB). Femoral head moves on acetabulum. Fémur=CONVEX Roll&glide: opposite directions! External-internal rotations IR: Femur Rolls anterior/glides posterior ER: Femur Rolls posterior/glides anterior 19  Kinetics of External Rotation Primary motor muscles -Piriformis -Obturator Externus -Obturator Internus -Gemellius Superior -Gemellius Inferior -Quadratus Femoris Secondary Motor Muscles -Gluteus Maximus -Posterior fibres of Gluteus Medius 20  Kinetics of Internal Rotation Primary Motor Muscles – Adductor Magnus (post head) – Adductor Longus – Adductor Brevis Secondary Motor Muscles -TFL -Anterior fibres of Gluteus Minimus -Anterior fibres Gluteus Medius -Pectineus 21  Limits of External and Internal Rotation External Rotation -Iliofemoral and Pubofemoral Ligament Tension Internal Rotation -Ischiofemoral ligament tension -Tension of the external rotator muscles that by their depth and tone act as active ligaments (Pelvitrocantereous Muscles) 22 Ostheokinematics External Rotation and Internal Rotation External Rotation -Tip of the foot out. -Mechanical axis of the femur. -60º amplitude Internal Rotation -Tip of the foot inward -Same axis as internal rotation -Amplitude of 30-40º 23  Arthrokinematics of the hip OKC Arthrokinematic Ostheokinematic Arthrokinematic (roll) (glide) Flexion anterior posterior Extension posterior anterior Abduction inferior superior Adduction superior inferior Internal rotation posterior anterior External rotation anterior posterior 24 Lumbopelvic rhythm: combined movements Combined & coordinated movements of:Hip-Pelvis-Lumbar spine to increase overall motion OKC Femur is moving (“ball in socket”): – Flex hip+PPT+lumbar flex – Ext hip+APT+lumbar ext CKC pelvis is moving (“socket in ball”): – APT+hip flex+lumbar ext – PPT+hip ext+lumbar flex 25 Lumbopelvic and femoropelvic rythm: combined movements CKC 26 Ostheokinematics of the hip Closed kinetic Chain (WB). Acetabulum moves on femur – Anterior-posterior pelvic tilt (APT:hip flexion PPT: hip extension) – Abduction-adduction (“hip hike”) – External-internal rotations (R pelvic rotation: R leg IR, L leg ER) 27 Ostheokinematics of the hip 28 Hip Joint “Open pack position”: The open–packed position for the hip joint is with the hip in flexion, abduction, and external rotation. This position is often referred to as the “hook-lying” position (Minimal congruence). Minimal congruence. 30º Flex 30º ABD, 5ºER “Close-pack position”: maximal congruence: extension, IR and abduction In this position is where we find higher congruence/stability, highest contact between articular surfaces. 29  Anatomical Variations and influence in the movement: hip alignment Projection of the femoral neck in relation to the axis of the femoral condyle of the femur. From an anatomical standing position These features will vary the standing internal or external rotation of the hip. 30