Prospective evaluation of canine partial limb amputation with socket prostheses.

BACKGROUND: Canine prostheses have been commercially available for many years but are still in early stages of research, development, and clinical application. OBJECTIVE: To prospectively investigate mid-term clinical outcomes of partial limb amputation with a socket prosthesis (PLASP) in canine patients via a descriptive prospective clinical case series and to describe a clinical protocol for PLASP. METHODS: Client-owned dogs (n = 12) with distal limb pathology for which total limb amputation was recommended were enrolled. Partial limb amputation was performed and a socket prosthesis was moulded and fitted to the limb. Complications, clinical follow-up, and objective gait analysis (OGA) were recorded for at least 6 months. An online survey was completed by owners after study completion. RESULTS: Ten dogs with thoracic limb pathology and two with pelvic limb pathology were included. The most common site of amputation was mid-radius (n = 5). Eleven of 12 dogs demonstrated quadrupedal gait on OGA with mean per cent body weight distribution (%BWD) of 26% on thoracic limb prostheses and a %BWD of 16% for the one pelvic limb prosthesis that OGA data were available for. Complications included prosthesis suspension difficulties (n = 5), pressure sores (4), bursitis (4), postoperative infection (3), prosthesis aversion (2), dermatitis (1), and owner noncompliance (1). Two owners elected to discontinue prosthesis use. CONCLUSIONS: PLASP allowed restoration of quadrupedal gait patterns in most patients. Owners reported overall positive satisfaction, though a high complication rate was observed. PLASP should be considered in select cases as an alternative to total limb amputation for dogs with distal limb pathology.

Biomechanical comparison of four prosthetic ligament repair techniques for tarsal medial collateral ligament injury in dogs.

OBJECTIVE: To compare joint stability and ultimate strength among 4 prosthetic ligament constructs for repair of tarsal medial collateral ligament (MCL) injury in dogs. SAMPLE: 13 canine cadavers (26 hind limbs). PROCEDURES: Each limb was stripped of all soft tissues except those associated with the tarsal joint and assigned to 1 of 4 prosthetic ligament constructs. The AN construct consisted of 3 bone anchors connected with monofilament nylon suture. The AU construct consisted of low-profile suture anchors connected with multifilament ultrahigh-molecular-weight polyethylene (UHMWPE) suture. The TN and TU constructs involved the creation of 3 bone tunnels and use of nylon or UHMWPE suture, respectively. Each limb underwent biomechanical testing before and after MCL transection and before and after cyclic range-of-motion testing following completion of the assigned construct. Tarsal joint stability (extent of laxity) was assessed with the joint in each of 3 positions (75°, 135°, and 165°). After completion of biomechanical testing, each limb was tested to failure to determine the ultimate strength of the construct. RESULTS: Relative to intact tarsal joints, joint laxity was significantly increased following completion of all 4 constructs. Construct type was not associated with the magnitude of change in joint laxity. Ultimate strength was greatest for the UHMWPE-suture constructs. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that all 4 constructs effectively stabilized MCL-deficient tarsal joints. Implants used for the TU, TN, and AU constructs had a lower profile than those used for the AN construct, which may be clinically advantageous. In vivo studies are warranted.

Design and Use of a 3D Prosthetic Leg in a Red-lored Amazon Parrot ( Amazona autumnalis).

A three-dimensional (3D) prosthesis was designed and built for a red-lored Amazon parrot ( Amazona autumnalis) with a pre-existing amputation of the distal left leg at the tibiotarsal-tarsometatarsal joint and injuries to the right leg caused by cage companion aggression. The prosthesis consisted of a straight main imprint, with a round element at both ends to provide stability, and a bridge connecting this to a socket without a bottom where the stump could be accommodated and held securely with self-adhesive bandaging. Over a 4-month period, 3 different 3D prosthetic models were made and evaluated. The first model was fitted, but the parrot would only use the tip of the main imprint to stand and walk. The second model was designed with a semicircular imprint with only 1 round element at the cranial end, a different bridge to accommodate the change to the main imprint, and the same socket. With these changes, the parrot was able to place the imprint of the prosthesis on the floor to stand and move freely around its enclosure. To accommodate morphologic changes on the stump, a third model was created consisting of the same imprint and bridge, but the socket was cut vertically all the way on one side to allow distention on its diameter and provide a long-lasting fit to the stump over time.

Rehabilitative Soft Exoskeleton for Rodents.

Robotic exoskeletons provide programmable, consistent and controllable active therapeutic assistance to patients with neurological disorders. Here we introduce a prototype and preliminary experimental evaluation of a rehabilitative gait exoskeleton that enables compliant yet effective manipulation of the fragile limbs of rats. To assist the displacements of the lower limbs without impeding natural gait movements, we designed and fabricated soft pneumatic actuators (SPAs). The exoskeleton integrates two customizable SPAs that are attached to a limb. This configuration enables a 1 N force load, a range of motion exceeding 80 mm in the major axis, and speed of actuation reaching two gait cycles/s. Preliminary experiments in rats with spinal cord injury validated the basic features of the exoskeleton. We propose strategies to improve the performance of the robot and discuss the potential of SPAs for the design of other wearable interfaces.

Orthoses and exoprostheses for companion animals.

Exoprostheses are devices that are secured to incomplete limbs to enable locomotion. By comparison, orthoses are devices externally applied to support or protect an injured body part. Orthoses also can be used to control, guide, protect, limit motion of, or immobilize an extremity, a joint, or a body segment. Exoprostheses and orthoses are a growing aspect of the physical rehabilitation of companion animals. They require precise design and fabrication. Patients and owners must be trained to use the devices. Exoprostheses and orthoses can have a profound beneficial impact on the mobility and the quality of life of companion animals.

Limb amputation and prosthesis.

Limb amputation is an alternative to euthanasia when catastrophic injury prevents successful restoration of the limb or when cost is an issue. Proximal limb disarticulation for amputation is preferred if a prosthesis is not considered. Distal amputations are needed to accommodate exoskeletal prosthesis. This article reviews the considerations and describes techniques for this surgery.

Implantation of a titanium partial limb prosthesis in a white-naped crane (Grus vipio).

A female white-naped crane (Grus vipio) was presented with an open, oblique fracture of the distal right tarsometatarsus and concomitant vascular and nerve damage. Conventional fracture fixation repairs failed, which led to implantation of a custom titanium limb prosthesis. After subsequent revisions with 2 different prosthetic devices, limb function was ultimately restored but a later yolk embolism caused a circulatory compromise in the opposite leg, which necessitated euthanasia. Histopathologic results revealed limited ingrowth of bone into the porous coated implant, which indicated that a limb prosthesis may provide salvage for long-legged, heavy-bodied birds with fractures of the tarsometatarsus.

Loss of implant-bone interface following distal radial locking-plate endoprosthesis limb-sparing surgery in a dog.

An eight-year-old, neutered female Rottweiler was presented with lameness of seven days duration. Radiographs were consistent with a distal radial bone tumour. Limb-sparing surgery was performed using a commercially available endoprosthesis with a locking bone plate. Histopathological examination of the resected bone revealed an intraosseous fibrosarcoma, and postoperative adjuvant chemotherapy was initiated three weeks after surgery. Despite initial satisfactory limb function, lameness worsened four months after surgery. Radiographs revealed large areas of bone lysis around the proximal and distal screws, leading to significant resorption of the radius and radial carpal bone with subsequent construct failure. Further treatment was declined by the owner and the dog was subsequently euthanased. This case illustrates that implant failure is not necessarily averted by the use of locking (compared with non-locking) implants combined with an endoprosthesis to treat distal radial tumours in dogs.

Intraosseous transcutaneous amputation prosthesis (ITAP) for limb salvage in 4 dogs.

OBJECTIVE: To report clinical application of intraosseous transcutaneous amputation prosthesis (ITAP) for limb salvage. STUDY DESIGN: Retrospective case series. SAMPLE POPULATION: Client owned dogs with malignant neoplasia of the distal aspect of the limb. METHOD: Distal limb amputation allowed press-fit insertion of the ITAP into the radius (n = 3) or tibia (1). Remaining soft tissues including skin were attached directly to the ITAP. Limb stump and ITAP were protected by bandaging (1) or external skeletal fixation (3) for 5-6 weeks before exoprosthesis attachment. Measures of outcome included subjective assessments of limb function by owners and veterinarians, radiographic (4) and histologic (1) examination. RESULTS: Dermal integration with the ITAP was achieved by 3 weeks and dogs were walking in a pain-free manner by 8 weeks. One dog was administered adjunctive carboplatin chemotherapy. No evidence of local tumor recurrence occurred. In 1 dog, ITAP fracture occurred at 10 weeks and was successfully managed by ITAP replacement. Three dogs were euthanatized because of confirmed or assumed metastatic disease at 8, 12, and 17 months. Histologic examination of the ITAP-limb interface at 1 year documented osseous and dermal integration. CONCLUSION: Implantation of ITAP to the distal limb of dogs is feasible and can result in favorable functional outcomes. Biological integration of osseous and dermal tissues with ITAP is reliable and robust.

Assistive devices, orthotics, and prosthetics.

Deciding on which supportive device, orthotic, or prosthetic is best suited for a given patient is a complex process involving many different factors. The ability to manage biomechanical abnormalities successfully may be enhanced by an understanding of the properties of the various materials that comprise these devices, their effect on functional performance, and other associated patient factors. Veterinary health care providers are faced with the challenge of effectively addressing the physiologic and fiscal needs of the patient in a rapidly changing patient care environment.