The latest issue of the International Journal of Sports Physical Therapy had several articles on patellofemoral pain (PFP).  After reading them, I thought it would be cool to put out some content on the material I found noteworthy and interesting.  The following article brought some perspectives I didn’t often consider when treating my patients for PFP.

Current Concepts In Biomechanical Interventions for Patellofemoral Pain by Willy and Meira,  The International Journal of Sports Physical Therapy, Vol.11, Number 6, Dec. 2016, pages 877-886

JOINT LOADING

  • The Patellofemoral Joint (PFJ) is subjected to 4.5-5x one’s bodyweight during running activity and and in excess of 10x their body weight with jumping.

QUAD STRENGTHENING

  • Quad weakness is a risk factor for Patellofemoral pain (PFP) and quad strengthening has been shown to reduce it by 44-90%
  • Single leg squats performed to at least 65 degrees of knee flexion without added weight yields peak quadriceps forces of approximately 4-5 times body weight.
  • Open chain knee extensions in the 45-90 deg. range and closed chain squats & leg presses between 0 and 45 deg. range are ideal exercises for strengthening quads; such movement ranges decrease the possibility of further joint irritation 
    knee-extension
    Knee Extension at 90 deg. and Leg press at 0 deg.  leg-press
  • The process of quadriceps strengthening, rather than the actual strength gains, may reduce PFP by improving load tolerance of PFJ structures.

HIP STRENGTHENING

  • Hip strengthening programs result in moderate to large reductions in PFP, and with moderate to large improvements in function in the short to medium term.
  • Hip strengthening alone does not appear to alter proximal (hip) mechanics, and non-biomechanical mechanisms may explain the reduction in PFP that is widely reported with rehabilitation programs that employ hip strengthening.

MOVEMENT RE-EDUCATION

  • Providing mirror and verbal feedback has been shown to be effective at reducing contralateral pelvic drop, hip adduction and hip internal rotation during a single leg squat.
  • Some studies suggest that improvements in hip mechanics during single leg squats do not directly transfer to running when applied to runners with PFP.single-leg-squat
  • If frontal and transverse plane hip mechanics are thought to be the main biomechanical factor contributing to a runner’s current PFP, visual feedback to cue reductions in hip internal rotation and adduction are warranted.
  • If sagittal plane running mechanics are primarily implicated in a runner’s PFP, then cueing an increase in step rate during running may be the most effective gait modification.

FOOT ORTHOSES

  • Foot orthoses combined with exercise therapy, resulted in improved outcomes over six weeks in individuals with PFP compared with exercise therapy alone.superfeet

RETURN TO RUNNING

  • Running athletes recovering from PFP may have greater success with bouts of moderately fast to fast paced running for a prescribed number of steps rather than focusing on slow jogging for a set amount of time.
    faster-paced-running-for-rehab
    Faster paced running for rehab.

    Faster running results in decreased stance times and fewer steps to cover a certain distance, resulting in decreased PFJ loads.

 

PERSONAL THOUGHTS

My Go-To approach to PFP has always been to address hip strength and mechanics,  and I’ve been relatively successful thus far.  All it took was a lecture from Dr. Chris Powers in PT school and I was sold.  When prepping for the OCS exam, I read that the idea of isolated VMO  exercises for PFP was flawed so I kind of put quad strengthening in the back seat of my tool box.  This article brought to light the idea that adaptations in the PFJ’s structures (articular surfaces, etc.) rather than the actual strength gains in knee extensors, as the the likely cause for symptom improvement.  I completed MedBridge’s online course on Patellofemoral Concepts for Rehabilitation with Terry Malone PT, EdD, ATC, FAPTA and he reiterated the importance of conditioning the joint’s articular surfaces in treating PFP, particularly in cases of OA.  I practiced a few years at a Sports Medicine facility where some were still doing VMO targeted protocols but with much success.  In hindsight, such success was probably due to PFJ structure conditioning rather than muscle strength gains.  After all this, I think I’ll continue to use my original approach to PFP but will definitely supplement it with specific and focused quadriceps strengthening.  The aforementioned online course went deep into isometric strengthening protocols so I’ll save that content for another post.

Knowing that the PFJ is subjected to over 10x one’s bodyweight during jumping activity is a pretty good reason to discourage plyometric style training for those carrying excessive weight.

fat-girl-jumping
Maybe not?

Running faster rather than slower during rehabilitative training was initially counter-intuitive for me but made sense after some thought.  That being said, I’m sure that training volumes definitely have to be specific and adjusted according to the patient’s tolerance.

It made sense to me how mechanics involved in the mastery of the single leg squat did not translate directly into running mechanics.  The concept of specificity always has to be addressed.  I’ve always made it a point to DRILL the mechanics into one’s gait. I progress them from single leg squats, to single leg hops, to alternating hops, to hopping with forward progress (single and alternating), and then into running drills; it’s my part-part-whole progression.  I use Gray Cook’s angle of reactive neuromuscular facilitation to promote hip abduction by running  next to my patients while holding a sport band around their waist and pulling them laterally towards me as they run forward; the patient’s inside hip has to generate greater abduction forces in order for them to follow a straight line of running.

running-with-lateral-resistance
Running with lateral resistance

I could imagine having to do the same intervention on a treadmill with patients I can’t keep up with but that’s yet to happen.

That’s it for now.  If you want access to the article, shoot me an email and I could give you some ideas on how to get it if you don’t have a IJSPT subscription.
Dave

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