Week 3 Lecture Flashcards
• Describe the biomechanical forces that act upon the patellofemoral complex and its clinical significance on
forces ect
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
How does the patella congruency change throughout normal ROM of the knee?
Biomechanics
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
Patella anatomy
post surface
sizes of patella
trochlea
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
List the patellofemoral joint stabilisers
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
Describe the Q angle
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’
List the most commonly diagnosed and least commonly diagnosed causes of
ANTERIOR KNEE PAIN
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 influences on Q angle
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 influences on Q angle
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
Poor motor control
• Discuss the significance of sub-optimal motor control around the hip and pelvis in relation to patellofemoral joint pain
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
Discuss the role of sub-optimal quadriceps function in patellofemoral joint pain
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
Describe the clinical features
and the factors which may lead to the development of patellofemoral joint pain
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
• Describe the key objectives of treatment and management and methods to achieve those objectives in patients with patellofemoral joint pain
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)
Which patients respond best to patellar taping?
Those with
Higher levels of pretaping pain
Less lateral patellofemoral tilt
Larger Q angle
In what ranges is it least painful for strenthening and flexibiliity excercises around the knee?
Ranges Contact area CKC pain OKC pain
0-45 Low LOW max
45-90 high max MOD
• Describe the clinical features and
key management strategies
of other non-traumatic causes of anterior knee pain including patella tendinopathy,
and bursitis (including Breaststrokers knee/pes anserine bursitis)
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