OrthoPets Blog

OrthoPets ACORN Stifle Study- University of Louisville Stifle Brace Study

Bertocci, Gina E., and Nathan P. Brown, “Biomechanics of an orthosis-managed cranial cruciate ligament-deficient canine stifle joint predicted by use of a computer model.” American Journal of Veterinary Research 78.1 (2017): 27-35.



To evaluate effects of an orthosis on biomechanics of a cranial cruciate ligament (CrCL)–deficient canine stifle joint by use of a 3-D quasistatic rigid-body pelvic limb computer model simulating the stance phase of gait and to investigate influences of orthosis hinge stiffness (durometer).


A previously developed computer simulation model for a healthy 33-kg 5-year-old neutered Golden Retriever.


A custom stifle joint orthosis was implemented in the CrCL-deficient pelvic limb computer simulation model. Ligament loads, relative tibial translation, and relative tibial rotation in the orthosis-stabilized stifle joint (baseline scenario; high-durometer hinge) were determined and compared with values for CrCL-intact and CrCL-deficient stifle joints. Sensitivity analysis was conducted to evaluate the influence of orthosis hinge stiffness on model outcome measures.


The orthosis decreased loads placed on the caudal cruciate and lateral collateral ligaments and increased load placed on the medial collateral ligament, compared with loads for the CrCL-intact stifle joint. Ligament loads were decreased in the orthosis-managed CrCL-deficient stifle joint, compared with loads for the CrCL-deficient stifle joint. Relative tibial translation and rotation decreased but were not eliminated after orthosis management. Increased orthosis hinge stiffness reduced tibial translation and rotation, whereas decreased hinge stiffness increased internal tibial rotation, compared with values for the baseline scenario.


Stifle joint biomechanics were improved following orthosis implementation, compared with biomechanics of the CrCL-deficient stifle joint. Orthosis hinge stiffness influenced stifle joint biomechanics. An orthosis may be a viable option to stabilize a CrCL-deficient canine stifle joint.

Key pointsPicture1.png


  • Orthoses for CCLD have been reported. Their efficacy is dependent on device, owner, care-provider (adjustment, fitting of device and rehabilitation) and animal factors.
  • Orthosis allows limited functional movement (rather than complete immobilization) according to 4-point force application system used in humans with ACL-tears with the following cranial constraints (quads, tibial tuberosity, distal tibia) and caudal constraints (semimembranosus and semitendinosus, gastrocnemius muscles and calcanean tendon)
  • However, stabilizing effect of canine stifle orthosis has not been investigated

Materials and Methods:

  • Previously developed and validated computer model (3-D quasi-static based on 33kg Golden Retriever) utilized to test Orthopets CCLD-orthosis (with 2 Tamarack hinges at stifle) that was molded specifically for the dog that the computer model was based on
  • A 3-D scan of the orthosis was then performed to import the orthosis into the previously developed stifle model and loads on the ligaments (caudal CL, MCL, LCL) and tibial rotation and translation (drawer) through stance phase were compared between CrCL-intact, CrCL-deficient and CrCl-intact and -deficient with Orthopets orthosis
  • Different hinge stiffness (Tamarack 740-L [high] and Vet-L-65 [low stiffness]) were also evaluated


  • CrCL-deficient stifle compared to orthosis-managed CrCL-deficient stifle showed reduced tibial translation (91%) and rotation (61%)
  • CrCL-intact stifle compared to orthosis (with CrCL-intact stifle) showed significantly different peak loads (i.e. orthosis changes the loads compared to an intact stifle):
    • Loads on the caudal cruciate (38%) and lateral collateral ligament (53%) were reduced while MCL increased (50%)
  • CrCL-deficient stifle compared to orthosis-managed CrCL-deficient stifle showed significantly decreased peak loads for all ligaments tested:
    • Caudal cruciate (90%), lateral collateral ligament (93%) and MCL (59%)
  • Hinge stiffness significantly impacted tibial rotation (decreasing rotation with increasing hinge stiffness)


  • Stifle orthosis for CrCL-deficient stifle reduced translational instability by 90% in this computer-model
    • The tested device (Orthopets stifle orthosis) significantly improved biomechanical stifle stability in the stifle with cranial cruciate ligament deficiency
  • Stifle orthosis for CrCL-deficient stifle decreased loads on the collateral ligaments and caudal cruciate ligaments in this computer-model
    • The tested device (Orthopets stifle orthosis) may prevent subsequent injury to ligamentous structures
    • The tested design appears to reduce loading of the lateral collateral ligament to a greater degree than medial collateral ligament
  • Hinge stiffness had the greatest impact on tibial rotation
    • If greater control of internal tibial rotation is required (such as pivot-shift cases) a stiffer hinge should be considered
  • While computer models have been previously validated and appear highly predictive some variables are introduced when using a ‘real’ patient that may change these results (such as the cuffs were ‘modeled’ as a straight line, the foam may compress over time etc.) – in other words the result of this model are likely superior to what can be accomplished in a clinical patient
  • Modeling limited because it was based on one patient at one time-point only


Hello LiLen and all of the wonderful OrthoPets team,

I spoke to Lilen this morning about my dog Levi who two years ago was suffering from a cruciate tear in his left rear leg. OrthoPets fitted him with a stifle brace and the whole process was so positive. At that time he was just 14 and I was uncertain about his ability to bounce back from such an injury at his age. I am very proud to say that this spring he will turn 17 years old!!! He no longer needs his OrthoPets stifle brace but he took to wearing it almost immediately.

The stifle brace gave his leg the stability to heal while keeping him active – this to me is the genius of these braces. At his age mobility is EVERYTHING!!!

When he was 12 he tore his right leg cruciate and I opted to have surgery. It took a full 6 months for him to be able to walk and move freely again and consequently he lost much of his muscle tone and mobility. While I don’t regret my decision (and recognize that surgery is the best course of action in some cases) the process was so arduous and tentative. It was so amazing to have the option to use the OrthoPets brace and be a lot more proactive in the healing process – and to be able to keep him moving!

I am so grateful everyday that somehow I connected with OrthoPets. Without their help, I would not be enjoying each and everyday with my happy and healthy pup! Thank you a million times over!!!

Courtney and Levi

December 2016 Email News from the Canine Rehabilitation Institute


In Our December 2016 Issue …

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October 2016 Email News from the Canine Rehabilitation Institute


In Our October 2016 Issue ….unnamed

Registration Is Open for March 2017 Classes!

Our Next Online Clinical Research Course Starts in January

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New Construction Pics from Wheat Ridge Animal Hospital

Pawsitive Changes: Project V.E.T.S. … and more!

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August 2016 Email News from the Canine Rehabilitation Institute

August 2016 Email News from the Canine Rehabilitation Institute


In Our August 2016 Issue … 

  • 4e17ddaa-703e-4c12-993c-2bcd0b3ef3cbRegister Now for Canine Sports Medicine in Germany!
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Dear OrthoPets
Just a quick note to tell you what a huge fan of OrthoPets I am!! When we first got the carpus brace for Keeper, we needed it right away following an unexpected follow-up surgery. LiLen worked with me to get it delivered super fast. The product is excellent, keeps the joint completely stable, is easy to put on and take off, fits perfectly (after one year of hard wear, not a single sore), is easy to retread, and is also factory reburbishable. I only wish we’d had it since the very beginning on the injury. Maybe if we had, he wouldn’t need to wear it the rest of his life. As it is, I’m incredibly grateful for this high-quality solution, as it allows Keeper to remain a four-legged dog. He’s found many ways to use it beyond its original purpose (e.g. door knocker). Kudos to LiLen and OrthoPets for an outstanding product and excellent customer service!

Thank you! Maria and Keeper

Patient Feature: Colville


Handsome fella!

Meet Colville (aka CJ), a 2 year old rescued Pittie mix currently cared for by foster mom Jennifer of Black Dog Second Chance Rescue in New York. Colville was born with agenesis of his distal right forelimb, meaning that his toes and paw never fully formed. Colville previously had a prosthetic limb from another manufacturer, but he received that prosthetic early in life and eventually outgrew it. When it became obvious from the way he was using it that his old device was too small and he would need a new prosthetic, Black Dog and Jennifer reached out to OrthoPets to make Colville’s next leg for him.

read more…

Mini horse gets his groove back with special hoof


Miniature horse Shine is fitted with a prosthetic hoof at Colorado State University’s Veterinary Teaching Hospital. (Photo: William A. Cotton/CSU Photograph.)

FORT COLLINS, CO — The James L. Voss Veterinary Teaching Hospital at CSU gave a 3-year-old miniature horse a new lease on life by using a 3-D printer and prosthetics to replace a missing hoof.

Shine was injured after a vicious dog attack left his left hind leg mangled and infected. Veterinarians at the hospital had to amputate the leg in order for Shine to survive.

According to Colorado State University, owners Jacque Corsentino and Lee Vigil told veterinarians to “do whatever it takes” to give the horse another chance at a normal life.

And thanks to Shine’s size — he’s 30 inches tall and 150 pounds — he was a good candidate for a prosthetic hoof.

It’s an uncommon approach, said Laurie Goodrich, associate professor of equine orthopedics at CSU.

Goodrich used measurements, Shine’s radiographs and a 3-D printer to build a replica of the horse’s hoof to help him stay balanced while he healed.

“It’s the first one I’ve done, but I’ve always wanted to try,” she said. “We had no way of preserving that limb … this was the only option to preserve his life.”

Shine was fitted with an artificial hoof from OrthoPets and now he is adjusting confidently to trotting. He is preparing to leave the teaching hospital and return home to his ranch in Florence, Colorado, later this week.

“He is so comforting. You know when you have horrible days? Shine is my therapy,” Corsentino said. “I think he would make an amazing therapy horse for wounded warriors or kids with disabilities.”

Colorado State University contributed to this report.

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This story about CSU/OrthoPets patient Shine first appeared at LIKE Human: http://usat.ly/1Swkw6g