Injuries and pathology of the paw are often overlooked; yet, they can result in significant discomfort and dysfunction. Thoracic paw injuries are especially problematic because of the normal disproportionate weight distribution compared with the pelvic limbs. Pelvic paw injuries also markedly affect comfort and ambulation because forward drive in faster gaits originates in the pelvic limbs. Additionally, paw injuries ultimately affect the entire mechanical structure regardless of affected limb because compensatory or adaptive gaiting alters function up the kinetic chain (proximal joints, spine, muscles, etc.). Examples common to digital pathology include the following: osteoarthritis of the metacarpal or metatarsal-phalangeal joints; sesamoid bone fractures; flexor tendon laceration, degeneration, or contraction; pathologic supination or pronation; digital luxation; and neuropathy causing loss of dorsiflexion, among others. Orthotic devices can be used to improve comfort, assist in healing, or rehabilitate some injuries. The challenge is affixing such devices to the limb; commonly, the device must include the antebrachium or crus for proper suspension. Device design must take into account pathology, overall therapeutic plan and prognosis, limb topography, normal and pathologic limb function, and practicality and comfort. Examples of 2 devices are shown in Figs 3 and 4. The first is a typical orthosis for severe pronation including a custom insert for digital realignment and a hinged paw segment with flexor assist. Patients with this injury have reduced propulsion potential because flexor tendon failure prevents active engagement with the ground (push off). The second device assists in dorsiflexion and propulsion in pelvic limb neuropathy. Using an adjustable elastic cord, the digits within the bootie are dorsiflexed while flexion of the tarsus and cranial swing of the pes are assisted by elastic recoil for ground clearance.
Orthoses provide protected motion within a controlled range, prevent or reduce severity of injury, prevent or relieve contracture, allow lax ligaments and joint capsules to shorten, and provide functional stability for an unstable limb segment. These devices should not be seen as a replacement for surgery, but complementary or adjunctive. They can be designed to restrict, block, enable, or guide range of motion. They can absorb, store, and return energy. They may provide progressive, controlled dynamic return to motion. They can block one plane of motion while allowing another to persist. They may compensate for limb length discrepancy. Importantly, these devices do not create dependency or atrophy unless intended or is an unavoidable consequence of severe injury.
There are many conditions amenable to prescription orthoses. Orthoses can be used as preoperative, postoperative, or “no-operative” solutions. In cases where surgery must be delayed, they can provide interim support, protect the limb, allow more comfortable and mechanically appropriate ambulation, and minimize disuse atrophy. In a postoperative situation, orthoses can provide a safe, effective, and dynamic alternative to traditional casting. Orthoses are also used when surgery is not possible. This might include patients who are poor anesthetic candidates, patients with comorbidities precluding surgery, the aged, injuries for which there is no surgical correction, and families with financial limitations, among others. These “no-operative” patients represent a large and heretofore underserved population.
Among the many custom pet braces and prosthetics OrthoPets fabricates, we also provide “adaptive devices” to support your dog’s mobility. In some cases, you may notice your dog limping and knuckling at the hind limb and paw. This can sometimes indicate a neurological condition. Some causes of this could be but are not limited to: degenerative myelopathy, spinal trauma, sciatic nerve injury, etc. The Toe-Up Device assists with increasing flexion of the tarsus (hock) while also keeping the hind paw in a corrected normal standing position.
Through the appropriate application and use of an OrthoPets Toe-Up Device, coupled with rehabilitation therapy, your pet can regain lost quality of life, mobility, comfort, and function.
Veterinarians have a history of creating assistive devices from items at hand using everything from duct tape to superglue, plywood to low temperature thermoplastics, and aluminum rods to PVC pipe. We have a tradition of a “MacGuyver-like” fortitude driven primarily by economics and a lack of veterinary-specific products in the past. Public demand and the redefined modern role of the companion animal as a family member have provided an opportunity to excel beyond one-off and novelty in veterinary health care. Our clients have recognized there is a gap in veterinary services in terms of managing limb dysfunction and loss, a gap long filled in human medicine.
Scientific rigor and a culture of evidence-informed medicine drive new understanding and ultimately innovative therapies for animals. The structural consequences of a dysfunctional or missing limb or limb segment are now recognized. As our understanding of the intricacies of quadruped mobility and biomechanics has grown, so have the variety and sophistication of mechanical assistive devices. Now they incorporate veterinary-specific hinges, composite plastics, titanium, carbon fiber, and specialty foam liners. Biomechanically sound designs improve fit and function. Surgical techniques such as subtotal amputation, intraosseous transcutaneous amputation prosthesis (ITAP), and rotational plasty are providing new opportunities and an expanding patient population. V-OP is evolving into a new subspecialty. Although it is true that techniques and materials used in H-OP can be translated to veterinary patients, specific modifications for quadruped ambulation and the significantly greater magnitude of force generated by these patients must be considered. A thorough understanding of the biomechanics and health issues of animals is essential to avoid injury to the animal, delayed healing, or delayed use of more appropriate therapies. The veterinarian is the key player in this process and must lead the way because of their knowledge of veterinary species and veterinary medicine. H-OP professionals will continue to serve a collaborative albeit secondary role. To do so, veterinarians must begin to educate themselves in this regard to best serve the demands and needs of their clients and patients.
Human orthotic and prosthetic (H-OP) practice traces its origins to ancient Egypt and Greece. Earliest assistive devices were made of leather and wood. In the 18th and 19th centuries, these materials were replaced with metal. Not surprisingly, the profession of bracing predates surgery; bone setters and appliance makers were skilled artisans. Modern orthopedic surgery rapidly developed in the 20th century with the advent of implants and safer anesthesia; ultimately, surgery replaced bracing and splinting as the cornerstone of orthopedics. Consequently, bracing became ancillary to surgery. In recent years, improved technology has led to substantial improvements in bracing techniques and a more discriminate parsing of surgical vs. nonsurgical cases. A clear example is the decrease in Achilles tendon surgery in favor of dynamic bracing and rehabilitation for human patients.
Today braces are more accurately termed orthoses. Orthoses are defined as any medical device attached to the body to support, align, position, prevent, or correct deformity; assist weak muscles; or improve function.2 The term orthosis implies dynamic control, whereas brace more accurately refers to static control. Both are needed in modern therapy, and “orthosis” is preferred as a general term for both types of mechanical devices. They are not a replacement for necessary surgery, but complementary.
Prosthetists were originally black smiths and armor makers. Materials included wood and leather, calling to mind the classical image of the peg-legged pirate. Later, metal was incorporated albeit lending a great deal of weight to these devices. In modern times, a positive consequence of war, if this can be said, includes medical innovation by necessity. The American Civil War resulted in tens of thousands of catastrophic limb injuries. J.E. Hangar is reportedly the first amputee of that war.3 He subsequently built his own prosthetic leg and ultimately the largest human prosthetic limb fabrication company in the United States, Hanger Inc, publicly traded on the New York Stock Exchange as HGR. In the late 1880s, his devices were available by mail order, typically selling for $75- $150, which is approximately $2000-$4000 in today’s dollars. These early devices served an important purpose, but were utilitarian at best and truly uncomfortable at worst.
Once again driven by human conflict, today lightweight materials, microprocessors, and neural integration have resulted in spectacular improvements in function including sensation and lifelike grasping appendages. These devices have allowed amputees to return to and excel in nearly all human endeavors including sport; no longer are these individuals relegated to “getting by” and “making due” with their injury. The goal is to thrive with few or no boundaries. Amputees still face many challenges, and rehabilitation remains critical to successful return to function, but the list of limitations is shrinking.
Over the past decade, there has been a tremendous increase in our understanding of physical fitness for animals coincident with an increased demand for maximizing quality of life for our companion animals. We now know that optimal movement and mobility can significantly affect the physical and mental health of our veterinary patients. Rehabilitation has moved to the forefront of modern veterinary medicine with the debut of the American College of Veterinary Sports Medicine and Rehabilitation.4 Not surprisingly, innovative human orthotists or prosthetists have been tapped to create one-off mechanical appliances to improve the mobility and functionality of the occasional veterinary patient. This seems to mirror the emergence of acupuncture, chiropractic, and rehabilitation therapy for animals in the preceding decades. During this time, human practitioners introduced and, not entirely legally, ministered to veterinary patients owing to a paucity of qualified veterinarians. We are in their debt in terms of introduc- tion; subsequently, veterinary medicine has embraced and advanced these modalities with species-specific scientific vigor. Likewise, many veterinary practice acts have recognized these modalities and redefined the legal use by nonveterinary practitioners. As of this writing, these therapies are emerging as main- stream rather than so-called alternative therapies. Likewise, V-OP is emerging from beneath the wing of H-OP. Recent media productions such as Disney’s A Dolphin’s Tale and PBS’s My Bionic Dog have recently brought V-OP as a therapeutic option to the public eye. Although these productions still leave the viewer with an impression that such cases are yet novelty, this is far from reality and the current state of the science.
Our awesome Australian Partner Clinic, Dogs in Motion, participated in this study about outcomes for canine stump socket prosthetic patients. Click the link below to read more!
This study on pressure sores as a result of different lengths of immobilizing casts was released yesterday–click the link below to read the study for more information. The the 3-point corrective system discussed is a cornerstone of our OrthoPets orthotic designs!
- Which anatomical joints are present and functional?
- What is the length of the residual limb segment distal to the last anatomical joint?
Casey will continue to work on specific rehabilitation exercises at home with his owner to ensure that he continues to do well. His owner reports he is a crazy dog and does laps around the yard in his prosthesis and has no trouble at all with getting around. We cannot wait to keep up with Casey’s progress over the next few months!
OrthoPets offers both orthotic and prosthetic devices to help with your pet’s unique case. But what is the difference between the two? Orthotic devices are used to help stabilize an injury or instability. Prosthetic devices are used to replace a partial limb segment and make up a limb length discrepancy for congenital defects or for partial subtotal amputation. Below you will find common orthopedic injuries and instabilities as well as how a device may benefit your pet. All of our devices are designed to assist your pet pre-operatively, post-operatively or in lieu of surgery. Please reach out to one of our Case Managers for more information regarding our prosthetic devices and your pet’s specific case.
Carpal and Tarsal Injuries
Injury to the carpus (wrist) can be complex because it is composed of 3 joints, 6 carpal
bones, 2 antebrachial bones (radius and ulna), and 4 or 5 metacarpal bones. There are multiple ligaments holding this structure together and injuries can occur at any of the joint levels (antebrachiocarpal, middle carpal, or carpometacarpal).
Injury to the tarsus (hock) can be complex because it is composed of 6 joints arranged in 3 levels, 6 tarsal bones, 2 antebrachial bones (tibia and fibula), and 4 (rarely 5) metacarpal bones. There are multiple ligaments holding this structure together and injuries can occur at any of the joint levels (tarsocrural, talocalcaneal, talocalcaneocentral, calcaneoquartal, cetrodistal, and tarsometatarsal).
Clinical signs of carpal and tarsal injuries include lameness, swelling, and mal-alignment. Mal-alignment can include hyperextension and/or increased angling of the paw toward the midline (varus) or away from the midline (valgus). Minor injuries will resolve with rest and a temporary splint, however more severe injuries may require surgery or an orthosis. Additionally, any of the associated bones can be displaced (luxated) or fractured. Injuries to the Achilles complex is covered in another document. Common surgical approaches include repair of large ligament injuries when possible, screw fixation of fractures of the larger bones, partial or complete fusing of the carpus or tarsus so that it no longer bends (articulates). Device design is paramount to success and depends on the type and severity of injury.
Careful consideration is taken in prescribing a device and its specific components. Important clinical variables surround use of a paw segment and whether articulation by way of hinges is possible.
- The paw segment is required in the following circumstances: short metacarpal bones, fracture of metacarpal bones, severe hyperextension, middle or distal jointhyperextension, subluxation, more than one plane of instability, excessive dewclaws, deranged digits, flexor tendon failure or shortening at the digits and wounds associated with the paw.
- Articulation (hinging) is ideal whenever possible in order to provide as close to normal limb use as possible. With this design, the carpus or tarsus can flex if appropriate and yet be limited to flexion within safe parameters only; this is called an arthrodesis-on- demand. Articulation cannot be provided under the following circumstances: severe carpal or tarsal malalignment, bone tumors near the carpus or tarsus, metacarpal or metatarsal fractures, and non-reducible bone luxations. When articulation is not possible, patients may experience an altered gait in the device.
Injury to the cranial cruciate ligament (CCL, also called the ACL) is the most common
orthopedic injury in the dog. This injury is due to a partial or complete tear of a ligament inside the stifle (knee). The resulting instability leads to pain and arthritis. There is no published study directly comparing use of a custom stifle orthosis to surgical stabilization for CCL injury in the dog.
Stabilization is recommended for best short and long-term function, quality of life, and
comfort. Stabilization is traditionally done surgically either with a joint realignment surgery (TPLO or TTA) or with a pseudo-ligament surgically placed outside the joint (tight rope or lateral suture). These procedures are considered the standard of care. In the past 7 years, the use of a custom orthosis (brace) has become available as an alternative to surgery when surgery is not appropriate for any reason. These reasons may include other health issues, unacceptable surgical or anesthesia risk, advanced age, and financial constraints, among others.
Even with an orthosis, surgery may be required. When the cranial cruciate ligament is
torn sometimes the meniscus is also torn. The middle or medial meniscus is most commonly injured and injury may occur at the time of the initial cranial cruciate injury or any time later due to too much activity on an unstable joint. A torn meniscus is very painful and if not treated it will cause continued lameness despite stabilizing the joint with surgery or an orthosis. If this occurs, a surgical procedure called a partial medial meniscectomy is required.
Because an orthosis is not the correct therapy for all patients, before choosing an orthosis the following points are important to keep in mind:
- The device MUST be put on and removed daily. The device is to be used all day every day, but must be removed at night. The orthosis stabilizes the stifle, tarsus or carpus from the outside only when ON, while surgery does so from the inside. The device is not used at night and your dog must not be allowed to move about (jump on or off bed, wander the house, go outside through a dog door, etc.). Wearing schedules vary based on the type of injury.
- Adjustments are expected and are a normal part of the custom orthosis process. The device is custom-made for your dog, and every effort is made to accurately fit the device. Two complimentary adjustments are included to help meet the requirements for an appropriate fit; your veterinarian will coordinate these adjustments. Increased activity and activity intensity can expose fit issues requiring further adjustments. Please follow all instructions with on how to monitor your pet, contact OrthoPets as well as your veterinarian promptly if you have concerns. If adjustments are required, it will be necessary to ship the device to OrthoPets with a turnaround time of 1-3 business days excluding shipping time.
- Follow-up is critical to success. An orthosis is considered a “durable medical device.” This means that proper use of the device is necessary to meet therapeutic goals and to ensure its safe application over the lifetime of your dog. In the first few months of fitting, your veterinary team, with the help of your OrthoPets case manager, will help coach you with regards to device use and rehabilitation. Annual to twice annual appointments are advised depending on age and activity of your dog. At these appointments, your doctor will thoroughly assess your dog’s orthopedic condition and evaluate the condition and fit of the device.
- The role of Rehabilitation. Most dogs adapt quickly to wearing an orthosis, however, behavioral techniques can facilitate this. Your dog will need to learn basic skills while wearing the device, which include: transitions (sitting, lying down, getting upstairs), and moving around on different types of surfaces (ground, carpet, hardwood floor, etc.). Orthopedic injury leads to compensatory abnormal movement and associated muscle strain and weakness. The best way to ensure the highest level of success is to follow recommended rehabilitation schedule and techniques. Each patient’s condition and abilities are unique and as such an individualized rehabilitation program is needed. Your veterinarian can help find a certified rehabilitation professional (CCRT or CCRP) in your area.
- A proactive approach to arthritis management is the second key to long-term success. If the joint itself is injured rather than a ligament alone, osteoarthritis may develop. Steps taken early and continued throughout your dog’s lifetime will make a difference in terms of regaining and maintaining comfort and an active life-style well into the senior years. Consult with your doctors for a comprehensive pain management plan.