OrthoPets Blog

OrthoPets February 2017 Case Study for the Canine Rehabilitation Institute

OrthoPets February 2017 Case Study for the Canine Rehabilitation Institute


4c0318c8-4bd3-4c56-9548-1a7b567ab3fa.jpgGibson is a 5-year-old MC Border Collie that lives in Mexico. His veterinarian is Dr. Gabriel Ramirez who has a long working relationship with OrthoPets. Dr. Ramirez frequently sees cases that have had complications elsewhere and is known to “think outside of the box” with the goal to his patients to gain their mobility back as quickly as possible. In Gibson’s case, he had a pancarpal arthrodesis. Unfortunately, the post-operative bandage was placed too tightly and caused tissue necrosis. The medical team tried to save the limb but eventually the “only” established option for him was a full-limb amputation. However, since the affected area was distal on the limb, the owner elected a sub-total amputation and prosthetic.

OrthoPets is currently gathering retrospective and prospective data on canine prosthetics, however, based on our current experience a few things are important when considering a prosthetic device: Prosthetic candidates should be amenable to handling of the residual limb and a long enough limb to allow appropriate suspension of the device and proprioception to properly use the device in a functional manner is necessary.

The combination of these two factors will translate into the functionality of the device and ultimately serve as a predictor for the success of the case. The total length of residuum is currently unknown, and it varies depending on the anatomy of the remaining limb. For example, we have some cases that show appropriate suspension with a mid-radius amputation while others don’t have prominent enough humeral epicondyles to allow successful suspension. In general, the more distal the better the chances to have a successful outcome. As such, Gibson is a perfect case for this treatment.

Regarding the surgical approach to a sub-total amputation with the goal of utilizing a prosthesis, it is important to consider the following:

  • Skin suture line location to avoid scar tissue formation on the weight bearing surface of the limb
  • Remaining soft tissue placement to encourage comfortable weight bearing
  • Identification of nerves to avoid placement over the residuum

Gibson’s amputation was performed so that the accessory carpal bone remained which created a bulbous distal end aiding with the suspension. The device was fabricated with a removable liner for replacements to be sent as needed rather than requiring the device to be sent to us. A traditional style prosthesis has a “fixed” liner that is connected to the shell requiring the entire device and additional steps to replace or change the liner. The removable liner approach allows us to replace, duplicate and adjust the foam liner without needing the entire device.

Gibson was fit with his prosthesis and immediately took very well to it! So far, Gibson’s device has not needed any adjustments aside from tread replacement which can easily be done by his owner. The entire team at OrthoPets as well as his medical team was pleased with the fit of the device and how quickly Gibson adapted to his old activities such as playing with a Frisbee. Gibson will need regular rechecks to ensure that the device is not only fitting well but that the device is still providing appropriate function to his affected limb.

For additional information: Colorado State University is conducting an ongoing study evaluating partial amputation in dogs. Read more here.

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

January 2017 OrthoPets Case Study for the Canine Rehabilitation Institute



OrthoPets Case Study: Bailey

Bailey is a 6-year-old MC Labrador that is currently a patient of one of our Partner Clinics in San Francisco. Dr. Illana Strubel, owner of A Well Adjusted Pet, has come to OrthoPets and studied the use of our orthotic and prosthetic devices to use with her patients.

Bailey presented in September 2016 with a history of toe touching weight-bearing and non-weight bearing lameness intermittently over the previous 4 months. The radiographs showed inflammation and DJD changes in the left stifle with mild changes in the right stifle as well. He had a medial buttress palpable bilaterally with minimal to no cranial drawer or tibial thrust palpable on awake evaluation. He did show adequate range of motion, was able to sit and lie squarely. His measurements showed a 1-2 cm muscle mass discrepancy between the left and right thighs on girth measurements. The radiographic and physical exam conclusion was that they suspected a chronic partial to complete cranial cruciate ligament tear, +/- meniscal injury, with secondary degenerative change and crus muscle disuse atrophy for the left stifle. The conclusion for the right stifle was suspicion for equivocal increase of right stifle joint fluid volume with minimal tibial osteophyte; concern for possible early/mild partial cranial cruciate ligament tear and +/- meniscal injury.


The owners’ goal was to avoid surgery on the left pelvic limb and increase Bailey’s comfort. Due to his discomfort, they had to decrease his walks, which led to a 10-pound weight gain. When OrthoPets received Bailey’s measurements, fiberglass impression and media, we were able to analyze his gait to determine the most appropriate orthotic design for him. In some cases, when a pet has non-prominent malleoli or an extended terminal stance tarsal angle, a tarsal cuff component is required for suspension of the orthosis because standard use of the tarsal anatomy will not be sufficient.

Bailey was fit with his stifle orthosis and has been doing very well. He is continuing his rehabilitation with Dr. Strubel. She reports that he is building back muscle mass and has been able to go on walks with the dog walker to get his weight back on track. His owners are very pleased with his progress, and best of all Bailey is happy!


December 2016 OrthoPets Case Study for the Canine Rehabilitation Institute


OrthoPets Case Study: Alley

unnamed-9.jpgIn October 2014, Alley was diagnosed with a grade II medially luxating patella and suspected cranial cruciate disease. Since the cranial cruciate ligament also controls internal rotation of the stifle, CCLD can result in MPL by allowing excessive internal rotation and cranial displacement of the tibia. Both of these contribute to the patella luxating medially. Alley was partial non-weight bearing for almost two weeks and unfortunately was also diagnosed with concurrent transitional cell carcinoma in her bladder. She had been a very active dog until then, however, due to the co-morbidities, surgery was not an option for the owner. They were looking for a palliative solution to keep Alley comfortable until her quality of life was no longer acceptable.

While the orthosis is able to provide global support to the stifle, we generally only recommend orthoses for the treatment of low grade (I-II) patellar luxations. With the addition of a tarsal cuff, we are able control rotation of the affected leg which may assist with controlling the luxation (by providing resistance to internal rotation that is usually controlled by the cranial cruciate ligament). However, with grade III-IV luxation and in dogs without cruciate disease, the orthosis cannot provide enough external rotation of the tibia to allow for appropriate tracking of the patella.

Alley received a stifle orthosis with a tarsal cuff. The stifle device needed a minor adjustment to increase the relief for her lateral saphenous vein as it was somewhat prominent and swelling was observed. Otherwise, the orthosis was an excellent fit and allowed Alley to eventually return to her normal activities. By November 2015, Alley’s stifle was fully stabilized with the luxation resolved. The owners began using of the orthosis as a sports device during periods of high-impact activities.

In March 2016, Alley suffered a similar problem on her contralateral leg. Since Alley had done well with the original stifle orthosis, the owners decided to pursue it again. Alley received a stifle orthosis with a tarsal cuff for her contralateral leg. She has been doing well with her new orthosis and has been able to return to her normal activities again.


November 2016 OrthoPets Case Study for the Canine Rehabilitation Institute

OrthoPets Case Study: Finley96ea1fc7-a5cc-4ada-bd0c-736f7d91a4f3.jpg

Finley is a 5-year-old Golden Retriever who received a custom tarsus paw orthosis from OrthoPets in February 2016.

Finley was hit by a car in 2015 and suffered massive tissue loss. After several unsuccessful attempts to accomplish bone union, Finley was diagnosed with a malunion of all metatarsals. At this point further options (including bone morphogenetic proteins and other reconstructive procedures) were considered, however the owners did not want to pursue further surgical options.

Orthoses as a treatment for non-unions are challenging since an orthosis cannot completely prevent the patient from loading through the fractures while vertical forces are applied. Furthermore, due to the instability in the lower limb due to the fractures, the device has to be worn 24/7. This can be associated with soft tissue complications including sores and dermatologic issues. In Finley’s case, the veterinarian discussed these concerns with the owner, but since Finley seemed very comfortable when walking around in a splint it was decided to pursue treatment with an orthotic device.

An impression of Finley’s limb was made as well as required length measurements for fabrication. A non-articulating tarsus/paw orthosis with the addition of a “clamshell” piece along the cranial aspect was designed to control the applied forces. A removable foam liner was fabricated to increase intimacy to the limb for additional support. The paw shell design featured a rockered bottom to ease her gait and help with propulsion.

Finley was fitted with her device in March 2016 and the owner reported immediately that Finley was very comfortable in the device! In fact, the owners felt that she was moving better than she did for a long time and she even started running on one of their walks! Finley is still using her device full-time so that she has the support she needs when she is allowed out in the yard for exercise and in the house even if she is lounging around. It is very important that Finley gets several air breaks throughout the day when resting. This device will continue to be something that she uses for life. Every 12-24 months, we will need to assess the foam liner to see if it needs to be replaced as it will become compressed over time. The tread on her device will be replaced as well as it wears down, similar to needing new shoes. When you receive an orthosis from OrthoPets, you not only receive a custom-made device, but you receive our services for the life of your or your client’s pet! 


October 2016 OrthoPets Case Study for the Canine Rehabilitation Institute


OrthoPets Case Study: Elliot


Initial delivery

Elliot, a 7.5 year old, neutered male, Bearded Collie, was presented to OrthoPets for fabrication of a custom orthosis to support a post-operative patellar tendon repair of the right hind limb. This patient was casted post-op to provide temporary stabilization. The goals for the orthosis were to rigidly stabilize the stifle in extension with the ability to allow motion over time for physical therapy and to encourage tendon healing while preserving the repair. The use of an orthosis was desired to facilitate daily range of motion exercises with the ability to immobilize the joint without having to re-cast on a daily basis.

An orthosis to support a patellar tendon repair is a complex design requiring additional componentry for stabilization, force distribution, suspension and eventual



dynamization. Device suspension is often challenging due to the limb being held in extension. The device design for this case included a cranial femoral shell segment, a cranial tibia and fibula shell segment and a caudal tarsus and paw segment. The stifle and tarsus joints are immobilized with metal bar stock. Dacron range of motion control straps were provided to the veterinarian in charge for the purpose of dynamization within the device system at a later time point. This componentry allows for both immobilization and restriction of joint range of motion at the stifle and tarsus. In addition, a neoprene tibial suspension sleeve was created for this patient, allowing for the recruitment of the calcaneus as an additional suspension location. The paw shell is an integral component as it resists gravitational forces to help unload the patellar tendon as well as assists in device suspension.

When a patient is taken out of a cast and introduced to an orthosis, swelling and skin
irritations are not uncommon. Bandages cause compression of soft tissues and


Sports brace configuration

can restrict blood and lymphatic flow. When the bandages are removed, the changes in blood and lymphatic flow in combination with gravity can result in swelling and limb edema. This in combination with the requirement to wear the device 24/7 creates challenges that require dedicated owners. This patient initially required frequent air breaks from the orthosis, soft tissue massage and other rehabilitation techniques to resolve the edema of the distal limb segment. Of course the owners need to be aware that no weight-bearing can occur during these air breaks. Telfa pads were also initially recommended to cover and protect skin irritations on this patient.

The patient’s physical rehabilitation regimen was continued and the patient was allowed gradual dynamization of the stifle and tarsus. With time, the device was transitioned into a sports brace configuration for long term use via removal of the paw segment, custom modifications to the strapping and the addition of foam and friction reducing materials to maintain device integrity and increase patient comfort and functionality.

The use of the orthosis for post-operative support along with the dedication of the client, medical and rehabilitation teams resulted in a very positive outcome for this patient. Today, this patient has fully recovered and is pursuing an active lifestyle with no lameness or other signs of injury.

September 2016 OrthoPets Case Study for the Canine Rehabilitation Institute


OrthoPets Case Study: Casey

Casey is an English Pointer who is her owner’s hunting companion. A few months ago, Casey returned from the field lame in the hind end, so her owner thought it would be best to take her to the veterinarian. On gait evaluation, Casey showed a mild lameness worse in the left hind limb. While there was no evidence of increased tarsal flexion (“dropped hock” or “crab-claw” appearance), palpation of the common calcanean tendons revealed thickening bilaterally especially at the insertion of the calcaneus. Radiographs showed areas of dystrophic calcification at the insertion of the tendon. The rest of the exam was within normal limits. Casey was diagnosed with bilateral (Type 3, which is a tendinosis only with no increased hock flexion) Achilles tendonopathy, with the left being more symptomatic that the right. While Type 3 injuries can progress to more severe injuries (frequently Type 2c), surgery is generally not recommended for these injuries since the tendon is intact. Casey was placed on restricted activity and referred to a rehabilitation therapist to discuss options for this patient, specifically custom orthotic devices to reduce the stress on the Achilles tendons while they heal.

The OrthoPets tarsal orthosis creates an external moment to stabilize the tarsus when the soft tissues are not capable of stabilizing it. For cases like Casey, the first stage is generally a tarsus paw configuration with a locked-out motion limiter. This device does all the work for the Achilles mechanism allowing the early healing stages to proceed by removing tension on the impaired tendon. By doing so, the device provides an optimal environment to allow the body to heal.

Once early healing has been accomplished, the orthosis can be adjusted to allow additional flexion as the patient is able to handle some, or all, of the forces acting on the tarsus via the Achilles mechanism. Commonly used assessments to determine integrity of the Achilles tendon are palpation, clinical symptoms, goniometry, measurement of the standing angle and ideally ultrasound. When the veterinarian decides to begin additional loading of the Achilles tendon, destabilization of the device is warranted.

Casey’s owners opted to move forward with bilateral tarsal orthotics in the hopes that the tendons will heal on their own, so that she can get back to hunting activities. Casey received bilateral articulating tarsal devices with articulating paw segments. Initially, Casey was placed in 165 degrees of tarsal extension with very limited movement allowed. As the tendon heals, Casey will gradually be allowed increased range of motion at the tarsus in increments of 10 degrees. If Casey shows signs of a full recovery, the goal is to remove the paw segment and to use the devices at times of high activity (such as hunting) to prevent further injury to her Achilles complex.

When dogs are able to demonstrate a standing tarsal angle when challenged (i.e. holding up the contralateral limb) of >135 degrees, they generally are able to transition into a sports brace. The sports brace conversion consists of grinding down the distal metatarsal shell removing the hinge attachment for the paw segment and adding a foam edge band to aid in device suspension. If this option is chosen, we will also replace the metal motion limiting component with a Dacron motion limiting strap allowing flexion to 120 degrees. Please note that due to these changes, this conversion is irreversible and therefore has to be considered carefully (if recurrence is observed a new device has to be manufactured).

If a dog does not start to show signs of recovery, the goals and device requirements need to change to match the fact that the tendon is not healing to the degree desired. This is particularly common in dogs that have more severe disease with an increased tarsal flexion angle. If this is observed, despite the environment being provided via the orthosis and the required owner compliance, it may mean that a patient will be fully reliant on the orthosis. In these cases, further or other treatment options such as regenerative medicine or surgical treatment in combination with the orthosis may be considered. Of course, tendon healing is slow and sometimes just giving it more time allows progression through the phases.

August 2016 OrthoPets Case Study for the Canine Rehabilitation Institute


OrthoPets Case Study: Fynn

Fynn is a 6-year-old Australian Cattle Dog with a love for life! He has plenty of energy but unfortunately, his body did not want to cooperate. In October 2015, he presented with progressive carpal hyperextension. At OrthoPets, we receive many inquiries for dogs with progressive palmi-/plantigrade stance. While traumatic injuries generally affect at the most two (front) legs, dogs with underlying reasons (such as immune-mediated polyarthritis, endocrine disease or chronic steroid administration) may present with all four legs affected. Regardless of the diagnosis, treatment is challenging but generally consists of treating the underlying disease to avoid progression and arthrodesis/-es of the affected joints. Of course, this treatment choice is rarely elected by owners if multiple legs are affected because of the invasiveness, morbidity and cost associated with multiple limb arthrodeses. At OrthoPets we offer custom-made orthoses to support these patients.
In Fynn, there was no history of a traumatic injury, and he presented “dropped” in all four legs. In addition to the carpal hyperextension, frontal plane instability was also present. Due to the degree of carpal hyperextension and multi-plane instability, OrthoPets fabricated bilateral non-articulating carpal devices with articulating paw segments. If he continues to deteriorate, his veterinarian will have the option to immobilize the paw segment as well to assist with propulsion and add additional control.
Fynn did great with the support and stability the carpal orthoses provided. He was able to begin increasing his activities. In March 2016, his disease progressed and he was diagnosed with progressive tarsal hyperflexion. Since he did well with his carpal devices, his owner decided to pursue bilateral tarsal devices.
OrthoPets fabricated bilateral non-articulating tarsal devices with articulating paw segments. The tarsal orthoses are similar to his carpal orthoses by providing the greatest amount of support and stability by not allowing articulation. The dynamic articulating paw segments on the tarsal devices can also be immobilized if he continues to deteriorate.
Fynn adjusted to having 4 orthoses quickly and has begun to return to the life he deserves. Great job, Fynn! You’re a rock star!


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