Week 4 Lecture 4B - Patellofemoral Joint Flashcards
The patella helps your leg move and it wouldn’t move as well without it because it acts as a pulley and increases the moment arm. Hard to extend knee without patella. They lose power in the quads without it.
Patella takes on a lot of load.
Patellofemoral Pain Syndrome (PFPS)
Pain in the (anterior/posterior) knee
20-40% of all knee problems
Prevalence rate:
15-30% adolescent & young adults
Female > male
AKA:
chondromalacia patella, anterior knee pain
Will see this a lot at out patient clinic.
anterior
Could be tear of the meniscus The patellar tendon Could be OA Could be lumbar spine Pes anserine – anteromedial part of the knee - Seargant – Sartorius, gracilis, semitendinosus Rule it out – by palpation
Meniscus rule it out by history , will behave differently – will catch and click and along the joint line
IT band – location differently – nobles compression test
Pain from lumbar spine – LQ screen – make them move their lumbar spine
Pain
Instability – patella is moving too much
Pain – could be anywhere on the knee
Provokes their pain – anything that compresses the PF joint, anything that loads the PF joint , squatting, leg extension, sitting with the knee flexed
Have them do the thing that hurts, do therapy, later on ask them to do that thing and ask them what their pain level is to track progress – asterisk sign
PFPS Diagnosis
- presence of patella (LOM/pain)
- Reproduction of patella pain with squat or loading activity (step up, step down)
- Exclusion of all other conditions that could cause (posterior/anterior( knee pain
pain; anterior
Scott dye – operate on his knee without anesthesia
Fat pad is (not innvervated/ innervated/super sensitive)
The anterior capsule is (not innervated / innervated/ super sensitive)
Cartilage wasn’t painful – it (is/isn’t) innervated
innervated/super sensitive; innervated/super sensitive; isn’t
Tight lateral – cut the retinaculum and loosen it up in those with PFPS
They have excessive nerve growth – more sensitive to pain – people with PFPS
Subchondral bone is innervated – cartilage wear (thin and degraded) – puts extra stress on the bone underneath it and that is why people have pain
Right in the middle of the joint – wears evenly . If only touching on the below pic – will cause a lot of stress
If doesn’t track well in flexion/extension it can ride the lateral rim which causes increased pressure
Sitting flexed at 45 , xray beam comes from 60
Pics – glided to the side in those with PFPS
Take measurements to see how far it is from normal
Should be 60 degrees medial.
Center to the apex of the patella is the measurement taken here.
Positive number - lateral
Take two images, one on top of the other – TT and TG
If tibial tubercle is on the lateral side, as the patella moves from flexion to extension , it would get pulled off to the side in a lateral direction. Would create increased stress on the lateral side of the patella
How deep is the trochlea – sulcus angle
As you move from flexion to extension, if the femur IR that (increases/decreases) the contact area.
Strengthening the vmo doesn’t work
Train on track – patella on femur
Now we think about it in reverse
decreases
Chris powers story
People that went into valgus – patella sitting on the (middle/lateral) part of the trochlea, contact area will be (more/less).
lateral; less
All pf pain is not the same, have to figure out what is going to treat it
Got it
Palpate and find the pain.
Is it the tendon? Have to differentiate it
MPFL – look at the pic – sometimes folks with instability have pain there.
Normal Patella Mobility
AAOS Evaluation
Superior glide: At 0°
(mid-patella/inferior pole) = joint line
Inferior glide: At 0°
(mid-patella/inferior pole) = joint line
1/4 to 1/2 of its width medially and laterally - (1-2/3-4) quadrants
It moves (less/more) superiorly than inferiorly .
inferior pole; mid-patella; 1-2; more;
Lateral glide – shift in the frontal plane. Whole thing is shifted laterally
Lateral tilt – shift in the transverse plane
Things shift laterally
A/P tilt – runs inferiorly
Rotation – he called it unicorn, hasn’t ever seen one
shorter on the lateral side – do a (medial/lateral) glide
lateral
Underneath the inferior pole is the infrapatellar fat pad which is really sensitive and highly innervated
Medial-Lateral Tilt
Normal Tilt 5 degrees (medial/lateral) (knee at 30 degrees)
Should slant to lateral side 5 degrees – more than that – tight (medial/lateral) structures like the IT band
lateral; lateral;
Can you get it above horizontal ? if you cant, it’s not normal – tight (medial/lateral) structures
lateral;
Should be about a 1to1 ratio.
Sitting position of the patella – if patella sticks out from up top when sitting – alta
Patella alta describes a patella positioned too high or more proximal than normal. Conversely, patella baja describes a low-lying patella or patella positioned more distal than normal.
Patella position: superior and inferior
Insall-Salvatti index T/P The Insall-Salvati ratio or index is the ratio of the patella tendon length to the length of the patella 30 degrees flexion _ - _ = normal More than _ = alta Less than _ = baja
Patella Alta or Baja:
-(Increases/Decreases) contact area
(increased pressure)
-Unstable?
Long tendon – the number will be above one
Short tendon – less than one
That affects the congruity of the joint
Will be unstable – long periods of the ROM not in the trochlea could lead to dislocation
.8-1.2; 1.2; .8; Decreases;
Pushing the patella into the trochlea to see if it hurts or reduces their pain.
If can’t maintain the contraction, positive test
This and the patellar compression test are shitty (according to prof)
Resisted KE at 15 deg, 45 deg, 90 deg
+ = Pain or reproduction of symptoms
Resisted knee extension at three diff positions
When you do that you push the patella into the trochlea to reproduce pain. If they have pain at end range – you prob won’t start there with therapy
An unstable knee can cause PF pain.
Diff presentations of PF pain
Classifications
Global Compression
(Increased/Decreased) patellar mobility
(Loose/Tight) soft tissue
Post surgical /immobilization
Lateral patellar compression syndrome:
(ELPS: excessive lateral pressure syndrome)
Tight (medial/lateral) structures
Pain can be medial (MPFL) or lateral or both
Instability
Subluxation / dislocation - (medial/lateral)
MPFL injury/ Medial stabilizers
(Deep/Shallow) trochlea - large sulcus angle
Q angle
TT-TG distance
Compression – hypomobile in all direction
Post op patients lose patella mobility
If someone has been in a brace could cause loss of mobility at the patella
Tight lateral structures - Tight IT band/tight lateral retinacula.
Instability – patella dislocates laterally normally. Can tear the MPFL which is a major medial stabilizer
Q angle / tt-tg – if they are large could cause dislocation
Decreased; Tight; lateral; lateral; Shallow;
Classification
Biomechanical dysfunction
Kinetic chain dysfunction Distal: Excessive (pronation/supination) Muscle length (G/S) Foot arch structure
Proximal: Structure hip strength- Recruitment Endurance Proprioception
Local: Patella structure Alta Baja (potential cause? – ACLR) Quad strength
Excessive pronation – IR of the tibia and femur. IR of the femur (increases/decreases) contact area.
Muscle length of gastroc and soleus
Foot arch – flexible flat foot
Baja – could be caused by ACLReconstruction
supination; decreases
Distal Factors
Subjects with PFPS:
Increased navicular drop
Increased Rearfoot (inversion/eversion)
Ankle joint ROM (TCJ)
Gastroc/soleus length
Component of pronation - rearfoot eversion
eversion;
Proximal Factors
Structure: The Hip
Femoral Anteversion: increased hip (EROT/IROT)
IROT of femur causes (decreased/increased) load on (medial/lateral) patella
IROT; increased; lateral;
Proximal Factors Strength PFPS vs Normals
Decreased hip (adduction/abduction) strength
Decreased hip (flexion/extension) strength
Decreased hip (internal/external) rotation strength
People with PFPS tend to have those impairments
abduction; extension; external;
Proximal Factors - Frontal Plane Projection Angle
PFPS caused by poorly controlled femoral (external/internal) rotation in weight bearing
FPPA (dynamic valgus) greater in subjects with Decreased strength of hip (ADD/ABD) and (IROT/EROT)
FPPA (dynamic valgus) (Lesser/Greater) in PFPS
internal; ABD; EROT; greater
Local Factors Patellofemoral contact area
Points of contact change with knee motion
No contact in full (flexion/extension) 15-20° = (middle/inferior) pole 45° = (middle/inferior) pole 90 = (superior/all portions) Full flexion = (superior and inferior/medial and lateral) aspects
Contact area increases with (flexion/extension) - Most at _ degrees
Patella Alta or Patella Baja can alter these
As patella moves from extension to flexion
Extension – sits above trochlea
extension; inferior; middle all portions; medial and lateral; flexion; 90
As you move deeper into flexion in the closed chain you have (less/more) PF reaction forces and PF compression
more
As you move from flexion to extension in the open chain, the PFJR forces (increase/decrease)
More PROM than AROM – Lag
increase
