PFJ Instability Flashcards
What is PFJ Instability?
A condition where the patella does not track properly within the femoral groove, leading to relatively frequent subluxation or dislocations.
What may cause PFJ Instability?
Previous traumatic patella dislocation where medial stabilisers are injured.
OR
Existing anatomical abnormalities of the knee
What is the clinical presentation of PFJ Instability?
AKP with episodes of mechanical instability (locking, clicking, giving way)
Is PFJ Instability a condition within itself?
It can be a stand-alone condition but it can also be a symptom of other conditions especially post-traumatic injury.
What may occur if recurrent dislocations and chronic instability is left untreated?
Progressive cartilage damage and resultantly severe arthritis.
What is the most common MOI for patellar dislocation?
Knee flexion + IR on a planted foot with a valgus force.
This accounts for nearly 95% of dislocations.
What are genetic risk factors which may predispose someone to PFJ Instability?
Trochlear Dysplasia (trochlear is shallow)
Patella Alta
Knee Valgus
What is the diagnostic procedure for PFJ Instability?
Normally diagnosed through a comprehensive history and assessment.
MRI, CT or Ultrasound can be performed to rule out structural deficits.
PFJ Instability commonly occurs due to increased ligament Laxity (hypermobility). How is hypermobility assessed?
Beighton Score: (out of 9, 4+ = hypermobile)
1) Bend forward and place hands flat on floor without bending knees.
2&3) Elbow Hyperextension
4&5) Knee Hyperextension
6&7) Pinky finger back past 90*
8&9) Thumb touch forearm
What is the J sign?
Tests for patella maltracking
Perform knee extension SOEOB.
+ve = lateral displacement of patella end range KE.
What is management of PFJ Instability look like?
There is no consensus cons. vs surg.
Conservative trialled first always.
Immobilisation and Rest then exercises and passive mobilisations.
