Hip joint A.k.a. coxofemoral jt. ROM Flex 0-1200 Hypertext 0-100 Abd 0-450 Add across 30-400 ER 0-450 IR 0-350 Close-packed Full ext, IR, Abd
Hip joint Open-packed 300 flex 300 abd Slight ER Capsular pattern Flex, abd, IR End feel Flex soft/firm Ext firm Abd soft/firm Add soft/firm IR firm ER firm
End Feels Normal: Flexion & Adduction Elastic or Tissue Approximation SLR Elastic Extension & Abduction Elastic/Firm IR & ER Elastic/Firm
Hip joint Tonic labyrinthine & optical righting reflexes Head effectively behaves as if it’s fixed in a vertical position Maintains head over BOS When hip flexor ms. Is tight, keep LOG w/in BOS Open-chain response = displacement of head from vertical (Fig. A) Closed-chain response = maintain head in upright position (Fig. B)
Hip joint Acetabulum of pelvis + head of femur Diarthrodial, ball-and-socket jt. w/ 30 freedom: flex/ext in sagittal plane abd/add in frontal plane IR/ER in transverse plane 10 function of hip To support wt. of head, arms & trunk (HAT) Also provides pathway for transmission of forces bet. Pelvis & LEs Hip tends to operate in a closed kinematic chain Proximal end = head Distal end = foot
Structure Acetabulum Concave socket Lateral, inferior, anterior (LIA) Roundness ↓ w/ age Inferior = acetabular notch Central/deepest part = acetabular fossa Anteversion = anterior orientation of acetabulum Men = 18.50 Women = 21.5 0 Pathologic ↑ = ↓ jt. stability, risk for anterior dislocation of femoral head
Structure Acetabular labrum Fibrocartilage rimming entire periphery Transverse acetabular ligament Roofof tunnel passage for blood vessels & nerves entering hip Has Center Edge angle (CE) or angle of Wiberg Men = 380 Women = 350 Smaller CE angle (more vertical) = ↓ coverage of head of femur, ↑ risk superior dislocation of femoral head ↑ w/age
Femur Frog-leg position FABER True physiologic position of hip A congruent fit under low load would lead to incongruence under high load Periphery of acetabulum in contact, fossa is non- articular
Hip capsule & ligaments capsule has major contribution to stability femoral neck = intracapsular greater & lesser trochanters = extracapsular thickened anterosuperiorly thin & loose posteroinferiorly Iliofemoral ligament Y ligament of Bigelow Origin = AIIS 2 arms fan out to insert = intertrochanteric line of femur Strongest ligament of hip Taut in hyperextension Superior fibers taut in adduction Inferior tense during abduction
Hip capsule & ligaments Pubofemoral ligament Origin = anterior pubic ramus Insertion = anterior intertrochanteric fossa Taut in hip abd & ext Ischofemoral ligament Origin = posterior acetabular rim, acetabulum labrum Insertion = spiral around femoral neck Spiral fibers taut during ext, loosen in flex
Hip capsule & ligaments Position of stability Full extension of hip Position of vulnerability Flex& add (such as sitting w/thighs crossed) Ligamentum teres Triangular Ligament of head of femur
Wt. bearing @ hip joint Medial trabecular system Medial cortex of upper femoral shaft Vertically oriented Medial accessory system is @ medial aspect of upper femoral shaft & fans out to greater trochanter Lateral trabecular system Lateral cortex of upper femoral shaft Responds to forces created during contraction of abductors & tendency of head/neck to bend as wt. is accommodated Lateral accessory trabecular system runs parallel w/ greater trochanter Zone of weakness Thintrabeculae, do not cross each other @ femoral neck
Arthrokinematics Movement of convex femoral head on concave acetabulum Femoral head glides opposite motion of distal femur Flex = Head spins posterior Ext = anterior spin When wt. bearing Femur fixed, concave acetabulum moves over convex femoral head Acetabulum glides in same direction
Hip Mobilization Flexion: Femur rolls superior & glides inferiorly on pelvis Extension: Femur rolls inferior & glides superior on pelvis Abduction: Femur rolls lateral/superior & glides inferior on pelvis Adduction: Femur rolls medial/inferior & glides superior on pelvis Internal Rotation: Femur rolls medial & glides lateral on pelvis External Rotation: Femur rolls lateral & glides medial on pelvis
Osteokinematics Flexion = 900 w/ knee extended Normal gait on level ground requires 300 hip flexion 100 hyperextension 50 abd/add/IR/ER Anterior pelvic tilt Sagittal plane Hip flexion ASIS anteriorly & inferiorly, symphisis down
Osteokinematics Posterior pelvic tilt Hip extension Symphisis pubis up Posterior pelvis closer to femur Lateral pelvic tilt Frontal plane One hip joint serves as pivot/axis Opposite iliac crest elevates (hip hike) or drop (pelvic drop) Reference is side farthest from supporting hip Pelvic rotation Transverse plane Occurs in single-limb support around axis of supporting hip jt. Forward rotation Side opposite supporting hip moves anteriorly Backward rotation Side opposite supporting hip moves posteriorly
Osteokinematics Lumbar-Pelvic Rhythm Open-chain E.g. reaching the floor Hip flexion up to 900 only Anterior tilt of pelvis on femurs Flexion of lumbar spine adds 450 E.g. side-lying abduction Lateral tilt of pelvis & lumbar spine adds 450 Closed chain response to motions of pelvis Keeps one or both feet on the ground Maintain head upright & vertical Anterior pelvic tilt during hip flexion = head & trunk displaced forward + lumbar extension Posterior pelvic tilt + lumbar flexion to keep head forward over sacrum
compensatory Osteokinematicspelvic motion co-hip motion lumbaranterior tilt hip flex lumbar extposterior tilt hip ext lumbar flexlateral tilt (drop) right hip add right lateral flexlateral tilt (hike) right hip abd left lateral flexforward rot right hip IR rotation to leftbackward rot right hip ER rotation to right
Hip jt. Musculature Flexors 10 Iliopsoas O = iliac fossa, lateral sacrum, IVD & bodies of T12-L4 vertebra, transverse process of L1-L5 I = lesser troch Rectus femoris O = AIIS I = tibial tuberosity Hip flexion w/knee flexed
Hip jt. Musculature Tensor fascia lata O = anterolateral lip of iliac crest I = iliotibial band Abd, IR femur Maintain tension @ iliotibial band (relieves stress on femur) Sartorius Straplike O = ASIS I = upper medial tibia Flex & abduct hip in either knee flex/ext
Hip jt. Musculature 20 = 40-500 flexion Pectineus Adductor longus Adductor magnus Gracilis
Hip jt. Musculature Adductors Pectineus O = superior ramus pubis I = femur, below lesser troch Medial to iliopsoas Adductor brevis, longus & magnus O = inferior ramus & body pubis I = linea aspera Anteromedially located Gracilis O = symphysis pubis I = medial surface tibial shaft
Hip jt. Musculature Extensors Gmax O = sacrum, dorsal sacroiliac ligaments, ilium I = superior fibers into iliotibial band, inferior fibers into gluteal tuberosity Hamstrings O = ischial tuberosity I = biceps femoris into head of fibula, Semimem & ten into medial tibia
Hip jt. Musculature Abductors Gluteus medius O = lateral wing of ilium I = greater troch Anterior fibers flex & IR Posterior ext & ER All abduct Gluteus minimus O = outer ilium I = greater troch Stabilize pelvis in unilateral stance
Hip jt. Musculature Lateral Rotators = all insert into greater troch Obturator internus O = inside of obturator foramen Obturator externus Close to gemelli Gemellus superior O = ischial spine Gemellus inferior @ inferior border of obturator internus Quadratus femoris O = Ischial tuberosity I = posterior femoral head Piriformis O = anterior sacrum Superior to sciatic nn
Hip jt. Musculature Medial rotators Anterior gluteus medius Tensor fascia lata
Hip jt. Pathology Arthrosis OA Tissue changes in aging Fx Due to abnormal ↑ of magnitude of force or weakening of bone Usually @ zone of weakness Femoral neck Bony abnormalities of femur Coxa valga Functionally weakened abductors ↓ hip stability Predispose to hip dislocation
Hip jt. Pathology Coxa vara ↑ hip stability Femoral head deeper in acetabulum ↑ risk for femoral neck fx Slipped capital femoral epiphysis = slide femoral head inferiorly Retroversion stable Out-toeing Anteversion Unstable, predispose to andterior dislocation of head of femur In-toeing Hip abductors fall posterior, functionally weak Paraplegia Y ligament permits standing balance when knee & ankle stabilized w/ orthosis
Knee Joint3 bones Femur, tibia, patella3 articulating surfaces Medial tibiofemoral, lateral tibiofemoral, patellofemoral all enclosed in the joint capsule Mobility is primarily by the bony structure Stability is primarily by the soft tissues * the knee complex is responsible for moving and supporting the body in sitting and squatting activities and for support for transfers and locomotive activities
Knee JointA double condyloid joint with 2degrees of freedom Flexion and extension / Medial and lateral rotation 0-120-150 degrees for flexion; Hyperextension 15 degrees
LigamentumpatellaeContinuation of the tendon ofthe quadriceps femoris muscleAttached above to the lowerborder of the patella andbelow to the tubercle of thetibiaGives the patella is mechanicalleverage
Lateral Collateral Ligament Aka fibular collateral ligament Cordlike structure attached to the lateral condyle of the femur and below to the head of the fibula Separated from the lateral semilunar cartilage by the tendon of popliteus muscle Taut during full knee extension & slack during full knee flexion Protects the lateral side from an inside bending force (a varus force).
Stabilizing role of thelateral collateralligamentPrimary restraint toadduction of the kneeSecondary restraint toanterior and posteriordrawer, when thedrawer displacementsare large. Combinedwith the other lateralstructures the lateralcollateral ligament is asignificant restraint toexternal rotation of thetibia.
Medial Collateral Ligament Flat band that is attached above the medial condyle of the femur and below to the medial surface of the shaft of the tibia Strongly attached to the medial semilunar cartilage Taut during full knee extension and slack during full knee flexion Composed of three groups of fibers, one stretching between the two bones, and two fused with the medial meniscus. Partly covered by the pes anserinus and the tendon of the semimembranosus passes under it Protects the medial side of the knee from being bent open by a stress applied to the lateral side of the knee (a valgus force).
Medial collateral ligamentfunctional unitsThe medial collateralligament is the primaryrestraint to abduction andinternal tibial rotation.Secondary role of MCL:Provides anterior kneestability, which isenhanced by externaltibial rotation.With anterior cruciatedisruption the medialcollateral ligamentprovides most of theanterior stability of theknee.
Oblique Popliteal Ligament Tendinous expansion of the semimembranosus muscle Strengthens the back of the capsule
Anterior Cruciate Ligament Attached below to the anterior intercondylar area of the tibia Courses superiorly, posteriorly & laterally; attaches to the lateral femoral condyle Prevents anterior dislocation of the tibia on a fixed femur or prevents posterior dislocation of the femur on a fixed tibia Checks lateral rotation of the tibia in flexion and to a lesser extent, check extension & hyperextension at the knee Helps to control the normal rolling and gliding movement of the knee Anteromedial bundle is taut in both flexion & extension, while the posterolateral bundle is taut on extension only
ACL:Primary restraint to anteriortranslation of the tibia andcontributes the most at 30°flexion.-Prevents hyperextensionof the knee- Secondary restraint tointernal tibial rotation- Resists adduction andabduction at full extension- guides the screw homerotation of the knee jointas it approaches terminalextension
Posterior Cruciate Ligament Attached below to the posterior intercondylar area of the tibia Courses superiorly, anteriorly and medially; attaches to the medial femoral condyle Stoutest ligament in the knee Prevents posterior dislocation of the tibia on a fixed femur or prevents anterior dislocation of femur on a fixed tibia Checks extension & hyperextension, and in addition, helps to maintain rotary stability and functions as the knee’s central axis of rotation Bulk of the fibers are tight at 30 degrees flexion and the posterolateral fibers are loose in early flexion
PCL:Primary restraint posterior translationof tibiaSecondary restraint external tibialrotation at 90° flexion,which reduces uponknee extensionNear full knee extension, theanterior bundle of the PCLslackens, and theposterolateral structuresbecome the primaryrestraint.
PCL footprintNo fan out like theACLThe fibers arealmost parallel tobone
Meniscofemoral Ligaments The ligaments of Humphrey and Wrisberg are meniscofemoral ligaments which run from the posterior horn of the lateral meniscus to the lateral aspect of the medial femoral condyle The anterior meniscofemoral ligament is known as the ligament of Humphrey The posterior meniscofemoral ligament is known as the ligament of Wrisberg In about 70 % of knees, there is either anterior meniscofemoral ligament of Humphrey or posterior meniscofemoral ligament of Wrisberg
Humphreyligament: (anterior meniscofemoral) isless than 1/3 the diameter of the PCL arises from the posterior horn of the lateral meniscus, runs anterior to the to the PCL and inserts at the distal edge of the femoral PCL attachment Wrisbergs ligament: (posterior meniscofemoral) usuallylarger than ligament of Humphrey (upto 1/2 the diameter of the PCL diameter) extends from the posterior horn of lateral meniscus to medial femoral condyle
Semilunar Cartilages (Menisci) Sheets of fibrocartilage with a thick peripheral convex border and a thin inner concave border which is attached to the capsule Upper surfaces are in contact with the femoral condyles and the lower surfaces are in contact with the tibial condyles Increase the congruency of the tibiofemoral articulations & distribute the pressure Lateral meniscus is “O” shaped Medial meniscus is “C” shaped and is thicker posteriorly than anteriorly
MENISCUS:Lateral meniscusMedial meniscusTransverse meniscalligamentPosterior menisco-meniscal ligamentAnterior/Posterior horn-attached to intercondylartibial plateau-vascular like periphery
Meniscal biomechanics andFunctional anatomyMedial meniscus has a firmbond to MCLLateral meniscus has noattachment to LCLBecause the popliteus tendonattaches to the posterolateralcorner of the lateral meniscus,there is some additionalmobility and decreasedvascularity in this location.The transverse ligament joinsthe anterior horns of the twomenisci.
Synovial Membrane Linesthe capsule Forms a pouch that extends up beneath the quadriceps femoris to form the suprapatellar bursa, anteriorly Extends downward on the tendon of the popliteus muscle forming the popliteal bursa, posteriorly
Bursa Related to the Knee Joint Suprapatellar Bursa Liesbeneath the quadriceps muscle Largest bursa and always communicates with the knee joint Prepatellar Bursa Lies between the patella and the skin Infrapatellar Bursa Superficial infrapatellar bursa: lies between the ligamentum patellae & the skin Deep infrapatellar bursa: lies between the ligamentum patellae and the tibia
Popliteal Bursa Surround the tendon of the popliteus; always communicates with the joint cavity Semimembranosus Bursa Liesbetween the tendon of this muscle and the medial condyle of the tibia May communicate with the joint cavity
The Screw Home Mechanism Refers to the terminal external rotation of the leg at the last 20 degrees of extension due to unequal condylar configuration, muscle torque action & ligamentous guidance During the last 20 degrees of knee extension, the tibia externally rotates about 20 degrees on the fixed femur Also called the terminal rotations of the knee In closed kinematic chain motion, terminal rotation is seen as internal rotation of the femur on the fixed tibia In open kinematic chain motion, terminal rotation is seen as the external rotation of the tibia on a fixed femur Rotation between the tibia and femur occurs automatically between full extension (0˚) and 20˚ of knee flexion. These figures illustrate the top of the right tibial plateau as we look down on it during knee motion.
DURING KNEE EXTENSION, the tibia glides anteriorly on the femur.
During the last 20 degrees of knee extension, anterior tibial glide persists on the tibias medial condyle because its articular surface is longer in that dimension than the lateral condyles.
Prolonged anterior glide on the medial side produces external tibial rotation, the "screw- home" mechanism.
The Screw Home Mechanism Reverses during knee flexion When the knee begins to flex from a position of full extension, posterior tibial glide begins first on the longer medial condyle.
Between 0 deg. extension and 20 deg. of flexion, posterior glide on the medial side produces relative tibial internal rotation, a reversal of the screw-home mechanism.
Closed Kinematic Chain Motion Aka proximal-on-distal segment kinematics A series of segment link motion with the distal end fixed on the ground or some immovable point e.g. standing up, squatting down Open Kinematic Chain Motion Aka distal-on-proximal segment kinematics A series of segment link motion with the distal end free in space e.g. raising lower leg, throwing a ball Kinematics A branch of mechanics that describe the position and motion of body in space, without regard to the forces or torques that may produce the motion
Osteokinematics Normal ROM: Flexion >130 Rotation: 10 OPP: 25 flexion CPP: Maximal Extension &tibial external rotation Normal End feels Flexion: Tissue approximation Extension: Elastic/Firm SLR: Elastic *Femoral condyles begin to contact the patella inferior at 20 of knee; flexion; progresses superior at 90 & medial/lateral at 135 of knee flexion
Arthrokinematics Concave Surface: Tibial Plateau Convex Surface: Femoral Condyles To facilitate extension: OKC: tibia rolls and glides anterior on femur CKC: femur rolls anterior and glides posterior on the tibia To facilitate knee flexion: OKC: tibia rolls & glides posterior on the femur CKC: femur rolls posterior and glides anterior on the tibia
Functions of KneeMuscles & theirChange of Actions
Leg movements by compartment (inleg all nn are branches of sciatic)
Lateral Leg (superficial fibular n.) Fibularis brevis/longus
Posterior Leg (tibial n.) Gastrocs and soleus Flexor digitorum longus Flexor hallucus longus
Vastus Intermedius Mostefficient knee extensor with least demand of force
Vastus Medialis Plays an important role in keeping the patella on track in gliding on the femoral condyles (tracking mechanism)
Vastus Medialis Oblique Themedially directed forces of the VMO counteract the laterally directed forces of the vastus lateralis, thus preventing lateral displacement of the patella in the trocklear groove
Biceps Femoris Externally rotates the tibia with respect to the femur
Popliteus Considered as knee flexor but has a poor leverage for this motion Medially rotates the tibia on the femur to initiate unlocking of the flexed knee
Quadriceps Muscles When coming to standing from sitting position, these act concentrically to extend the knee When coming to sitting from standing position, these act eccentrically to control the rate of knee flexion
Gastrocnemius Flexesthe knee simultaneous with plantar flexion of the ankle
Knee Alignment & Deformities Tibio-femoral shaft angle is seen anteriorly on an extended knee which is about 170 degrees in a normal adult Genu Valgum or Knock Knee: refers to an angle that is less than 170-165 degrees >195 if ant Genu Varum or Bowleg: refers to an angle that approaches 180 degrees or greater <180 if ant Q Angle: an angle formed by the tendons of the quadriceps femoris and ligamentum patellae; N= 15˚ Genu Recurvatum: an excessive hyperextension that develops from weight bearing on an unstable knee