Laurie's Blogs.


Mar 2022

Novel MPL Repositioning Technique

MPL paper info


Background and Purpose: medial patellar luxation (MPL) is a common condition managed with surgery, medication, and observation.  There is a lack of literature regarding specific conservative MPL intervention.  Conservative treatment is important for milder non-surgical cases to prevent progression of luxation and future joint degeneration.  The purpose of this retrospective study is to document and investigate the significance of manual 3D repositioning technique, developed by Dr. Susan Davis, on outcome scores of small dogs and cats having medial patellar luxation (MPL) grades one or two.

Methods: Data from 37 eligible medical records were statistically analyzed using Wilcoxon signed-rank test.

Findings: A statistically significant different (p<.01) was found using manual 3D patellar repositioning in reduced lameness and improve functional scores for a combined sample size of 37 canine and feline patients between initial evaluations and discharge and in a separate analysis of 29 dogs (p < .01 lameness, p = .014 function) in separate analysis of a smaller sample size of 8 cats.

Clinical Relevance: Physical Therapy for MPL grades one and two should include manual 3D patellar repositioning in small dogs and cats.  An average of 6 visits is effective, though neutered mail may take longer.

Conclusion: Manual 3D patellar repositioning is effective in reducing lameness and increasing function in small dogs and cats having MPL grades one and two.


First off, what was the technique?

Check out these videos…

 MPL Technique

VIDEO 1 (Canine Example) –

VIDEO 2 (Feline Example) –


Okay… so I had some questions and the author is the one that had emailed me this paper… so I emailed her my questions.  Below is our discussion!


Was any other PT intervention done with these dogs?  (i.e. strengthening, stretching, etc.?)

Yes, various interventions like laser, stretching, etc. The treatment plans varied per species and individual patient, but all had in common the 3D technique. We excluded patients that didn't have the technique performed. Keep in mind it is a level of evidence lower than a RCT, SR... obviously. We didn't study this technique in isolation so I consider it more of a level 2B evidence.


I love the biomechanics of the technique you developed, but how would it compare to just ’straightening the stifle and pushing the patella over’?

Well, I had hoped that was obvious in the study, the fact that it utilizes the screw-home mechanism and is a 3D technique, using a combined maneuver in 3 different planes. Not just stifle extension in the median/sagittal plane. And often it isn't necessary to 'push the patella over' because the rotational components in the dorsal plane and the long axis distraction applied at the end do the trick most of the time. For argument's sake I guess you could assume the screw-home automatically occurs with simple stifle extension, but we know as PTs that joint play is often sluggish when other factors are present like inflammation, and loss of terminal extension if ROM is limited, etc. Manual techniques are needed to re-establish normal arthrokinematics.


Was the goal to give owners a technique to use to correct the patella luxation in real time, so as to avoid long periods of the patella being luxated?

Yes, that... and to encourage our colleagues to address patellar luxation at grades 1 and 2 instead of how we typically don't do much until it reaches stage 3 and 4. My co-authors and I were impressed by the literature review for both human and veterinary patients that long term duration of patellofemoral pain and instability is the most consistent predictor of poor patient outcomes and if left untreated it often results in progression to grades 3 and 4. The real issue is there is no 'money in this'... a simple technique that doesn't involve fancy expensive equipment will likely get swept under the rug. 


I guess, really my question is where does this fit into the overall ‘rehab’ of these dogs?

A great question and one we addressed in the recent presentation to IAVRPT in February. The video of that presentation given by me and Dr. Baris is in the member section of the IAVRPT website under Coffee and Cases ( Here's the simple answer: our literature review found that there was great evidence for a manual technique in the overall intervention of  patellar instability and prior to exercise. It should not be used in isolation but in combination with exercise. The takeaway is : treat it early, use a manual technique, with exercises, applying it (the technique)  just prior to exercise. We had a word limit with the publication and couldn't go into great detail everywhere we would have liked so as it reads, you have to sift some of this out... which is why we LOVED having the opportunity to do a one-hour presentation to take a deep dive.


So!  There you have it, a new re-positioning technique.  Something additional to add to your MPL treatment repertoire!  Cool!  And thank you to Susan Davis, PT for graciously allowing me to print our Q & A conversation as my blog for this week!