Week 3 Lecture

Considerable force transmitted cross PFJ – ½ body weight during walking up to 25X body weight on lifting a weight with knees flexed at 90. Patella = largest seasmoid bone Patellofemoral articulation -displaces the fulcrum of motion of the extensor mechanism anterior to the femur, -this produces a mechanical advantage increasing the force of the quadriceps muscles in extending the knee Patella centralizes the divergent forces of the quadriceps muscle and transmits the tension around the femur to the patellar tendon • greatest compression occurs in loaded flexion

In full extension the patella lies superior to the trochlear cartilage Flexion 0-30 the patella articular surface begins to engage with the trochlea, little to no articulation (0-45) Between 30-90 flexion, first the inferior and then the superior patella cartilage articulates with the trochlea cartilage (45-90) Beyond 120 knee flexion contact decreases between the patella and trochlea • at 130 flexion most contact with lateral facet and odd facet

Posterior surface of patella has: large lateral facet Medial facet Odd facet (on medial side) Patella alta- high riding patella Patella baja- low riding patella Patella piccolo- small patella (articular stress) Trochlea is the intercondylar groove of femur Medial femoral condyle is typically larger Lateral femoral condyle hypoplasia leads to the under constrained patella & lateral dislocation

Proximal structures Rectus femoris Vastus intermedius Quadriceps tendon Distal structures Patellar tendon Medial structures VMO Medial patellofemoral ligament Medial retinaculum Lateral structures ITB Lateral patello femoral lig Lateral retinaculum can be grouped into passive and active stabilisers

The effective line of pull of the quadriceps Formed between two lines joining: ASIS, center of patella center of patella and the tibial tuberosity. Normal Q-angle is 10-12 M and 15-18 F The larger the angle = greater the lateral patella ‘pull’

Most commonly diagnosed Patellofemoral pain syndrome (PFPS) Patella tendinopathy Fat pad impingement Less commonly diagnosed Bursitis Osgood Schlatters Sinding larsen Johansson Referred pain from the hip

Static (structural) -Genu valgum -Excessive femoral anteversion ( internal femoral torsion) (Patella is induced laterally into trochlea as distal femur rotates under it.) -Excessive tibial external torsion Tibial tubercle is positioned laterally > lat patellar displacement

Dynamic(Functional) Non local issues Prox: Poor frontal & transverse plane control at the hip Distal Prolonged and/or excessive foot eversion Loss of ankle dorsiflexion Local Issues: Lateral retinaculum contracture Shortened TFL/ITB Vastus lateralis contracture/tightness Hamstring tightness (BF inserts partiallyinto lateral retinaculum

DYNAMIC VALGUS Adduction Internal rotation Contralateral pelvis drop of stance hip Increases Q angle which lateralises patella If hip control is poor distal femur is allowed to move medially under neath the patella and the patella is effectively lateralised results in patella mal tracking during funcion > PFJP Weaknes of certain muscles that oppose this: Adductors- superficial gluteals External rotators- Deep gluteal group - Glut max & post fibres glut med

Weak gluteals > increased compensatory quads activation T/f increassed load at the knee VMO has no critical role providing medial support ofPFJ IN PFP group vastus lateralis was activated for much longer than VMO even though they switch on at the same time • Quadriceps activity may be better observed in 45-90 degrees of flexion and for CKC 0-45 degrees may reduce compression • Assessment of IRQ in OKC pain position is useful differential diagnosis for PFPS

Body chart Pain anterior Crepitus Typicaly secondary to repetitive/cyclic loading with gradual onset. Primary onset due to trauma Aggravating factors: Activities with repetitive loaded knee flexion-extension Provoked by prolonged knee flexion Extrinsic factors: Training type and loads Occupation Changes in footwear, intensity, surface

Motor control impairment AIM: normalise suboptimal postures loading strategies, movement control &/or muscle imbalances * more in guide p 294 Quad training Hip strength training Patellar taping Combined interventions Strengthening and flexibility excercises Stretch lateral constraints Strengthen medial constraint Straighten top to bottom In which ranges is it least painful for strengthening and flexibility excercises? CKC-0-45 (low) OKC 45-90 (mod)

Those with Higher levels of pretaping pain Less lateral patellofemoral tilt Larger Q angle

Ranges Contact area CKC pain OKC pain 0-45 Low LOW max 45-90 high max MOD

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A type of Adolescent traction apophysitis Osgood schlatters(OSD)(osteochondrosis) Involves tibial tubercle and the immature ossification centre beneath Derangement of normal processes of bone Localised tissue necrosis followed by full regeneration of healthy bone tissue Sinding larsen Johansson Affects distal pole of patella Mx of these Symptoms resolve when skeletally mature Sport participation guided by symptoms Address any coexisting factors or muscle imbalances

(Hoffas Syndrome) Causes Local trauma, post surgery, genu recurvatum ( knee hyperextension) Inferior pole tilt ( inf pole buried deep in FP) Pain ant and inf , swollen & puffy MOI-Typically repetative loading (2) w gradual onset -Trauma (1) acute injury Aggravating factors Loaded WB activities Prolonged standing, stairs End of range extension activities Biomechanics Common posture hyperextension sway back ( post capsule overstretching) Solution: bracing/ taping motor relearning/posture correction Post pelvic tilt Neutral knee Increase dorsiflexion range if limited

ITB function- controlled adduction Knee joint stabiliser Assists knee joint extension @30 F to E moves and to lat fem epicondyle @>30 F moves posteriorly Source of symptoms Compression of highly innervated layer of fat and connnective tissue that separates ITB from epicondyle Causes Dynamic valgus- weak hip adductors Tight TFL/ ITB Increasd hip adduction & IR Increased max rear foot inversion