Knee- PFPS Flashcards
What are some other terms for patello-femoral pain syndrome?
- PFPS
- anterior knee pain
- retropatellar pain syndrome
What are the patello-femoral GRF with walking?
50% body weight
What are the patello-femoral GRF near 30 degrees of flexion?
= to body weight
What are the patello-femoral GRF during stair climbing?
3x body weight
What are the patello-femoral GRF during squatting?
> 7x body weight
When are the patello-femoral GRF at their peak?
at 90 degrees flexion
What happens with the patello-femoral GRF in those with PFPS?
EVEN GREATER
What is the prevalence of PFPS?
- 37% of military recruits
- 70-90% recurrent and persistent
Why is PFPS so common in military recruits?
- overuse, bending squatting and harder activities with CC knee flexion
What are risk factors for PFPS?
- military recruits
- dynamic NOT static excessive pronation
- Biological females > males
- Patellar and femoral bone shape (FAI?)
Why is PFPS more prevalent in females?
- larger Q angle
- Less hip strength and coordination
Is PFPS usually due to trauma?
NO- rare
What is the typical etiology for PFPS?
Idiopathic (largest % of patients)
What is the theory of PF malalignment and/or maltracking?
- patella glides and tilts more laterally relative to femur
What does the PF malalignment and or maltracking theory involve?
- DECREASED surface area contact between patella and femur
Why could there be DECREASED surface area contact between patella and the femur?
- patellar and femoral bone shape
- excessive femoral IR
- quad weakness, incoordination, and atrophy
- unclear contribution from excessive pronation and tibial IR
What are the pathomechanics of PFPS?
- overload of patellar subchondral bone, especially lateral facet
- tissue ischemia
- loss of tissue homeostasis
- neural ingrowth and increase in substance P nerve fibers that transmit more pain
What are the structures involved with PFPS?
- subchondral bone of patella
- infra patellar fat pad
- bursae
- quad and pat tendons
- synovium
- med and lat retinaculum (holds patella and tendon in positioning)
Where is the infra patellar fat pad located?
- behind the patellar tendon and in front of the capsule
How can the infra patellar fat pad get inflamed?
- with excessive tibial IR and patellar hypermobility
Where can the pain from the infra patellar fat pad refer to?
the groin
Where are the bursae of the knee?
- superficial infrapatellar inbetween skin and patellar tendon
- deep infra patellar between patellar tendon and tibia
What is the onset of PFPS?
more often a gradual onset
Where is the pain with PFPS?
- anteromedial knee pain
- involved structures
** fearful of pain - inhibits VM activity
What increases pain with PFPS?
- stairs, squatting, or kneeling or prolonged sitting
Why can prolonged sitting cause pain with PFPS?
- compression during the knee flexion positioning is the CPP of the PF joint. prolonged sitting holds it there without the best contact under compression causing pain if the patient sits long enough
What can we observe with PFPS?
- increased Q angle
- OC maltracking of patella
- quad atrophy
- impaired LE control
What comes along with impaired LE control with PFPS?
- proprioceptive deficits
- dynamic excessive pronation
What can dynamic excessive pronation lead to?
- possibly tibial IR
- may contribute to greater genu valgus
- possible contributions from impaired DF bc if DF limited = more EV occurs
What makes up pronation? Why is this important for DF with PFPS?
forefoot abduction, eversion, DF
- if impaired DF, abduction and eversion get larger to compensate
What kind of impaired LE control can we observe with PFPS?
- abnormal planar motions, esp in biological females