Orthoses and exoprostheses for companion animals

Prospective evaluation of complications associated with orthosis and prosthesis use in canine patients

Introduction

The use of orthoses and prostheses is expanding in veterinary medicine. However, research evaluating the efficacy and complications of these devices in veterinary patients is limited. The primary objective of this study was to prospectively determine the complications and outcomes associated with custom orthosis and prosthesis use in the canine patient.

Materials and Methods

This was a prospective, clinical trial that followed patients for 12 months following device fitting. Owner-perceived complications, clinical metrology instruments, and objective gait analysis were used as outcome measures at various time points. The patients were grouped into the following four major categories: Patients with a carpal orthosis, patients with a stifle orthosis, patients with a tarsal orthosis, and patients with a prosthetic device.

Results

Forty-three patients were included in the study. Thirty-nine out of 43 patients (91%) experienced at least one complication, with 7/7 (100%) prosthesis patients experiencing at least one complication. At least one skin complication was reported for the following patient groups during the first 3 months of use: 8/14 (58%) stifle orthoses, 9/10 (90%) carpal orthoses, 6/10 (60%) tarsal orthoses, and 4/7 (58%) prostheses. Patient non-acceptance of the device was identified in 2/15 (14%) stifle orthoses, 1/10 (10%) tarsal orthoses, and 4/7 (55%) prostheses. One out of 15 (7%) stifle orthoses, 4/10 (40%) carpal orthoses, 4/10 (40%) tarsal orthoses, and 1/7 (15%) prostheses experienced mechanical device problems necessitating repair. The majority of patients with carpal and stifle orthoses showed improvement on objective gait analysis in percent body weight distribution of the affected limb between baseline and the most recent follow-up without the device donned: 83% (n = 6) of patients with carpal orthoses, 100% (n = 11) of patients with stifle orthoses. None of the patients with tarsal orthoses showed a similar improvement (0%; n = 4).

Discussion and conclusion

Three major complications associated with canine orthosis and prosthesis use were identified in this study as follows: Skin complications (abrasions, loss of hair, and sores), mechanical device problems, and patient non-acceptance of the device. Owners should be notified of these potential complications prior to pursuing orthoses or prostheses as a potential treatment option. Although clinical improvement was noted in the majority of patients with stifle and carpal pathology, given the lack of a control group, it is unknown how much of this improvement can be attributed to the orthoses.

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.

Implantation of an Intraosseous Transcutaneous Amputation Prosthesis Restoring Ambulation After Amputation of the Distal Aspect of the Left Tibia in an Arabian Tahr (Arabitragus jayakari)

Objective: This document is to report the clinical application and outcome of custom designed Intraosseous Transcutaneous Amputation Prosthesis (ITAP) in the left hind limb in a wildlife Arabian Tahr (Arabitragus jayakari).

Sample Population: A 4-year-old, 15 kg Arabian female Tahr from the Omani Mammals Breeding Center.

Method: The distal aspect of the left tibia was amputated due to trauma. A custom designed ITAP was inserted into the tibia 5 months after amputation. Two weeks after the surgery an exoprosthesis was attached to the limb. The outcome of the surgery was measured by means of assessments of the limb function and radiographic examination.

Results: Fourteen days after surgery the exoprosthesis was attached. The animal was walking showing lameness grade 2/5 (AAEP lameness scale). Within three weeks lameness improved to grade 1/5. Skin integration with the ITAP was achieved within 28 days. The Tahr was successfully reunited with the breeding herd.

Conclusion: Application of the ITAP to the left tibia of the Arabian Tahr resulted in positive functional outcomes. Six months post-surgery observations confirmed ambulation with grade 1/5 lameness was restored. The animal was reintroduced to the breeding group.

Clinical Relevance: ITAP offers a viable option to restore functionality and ambulation in wildlife.

Retrospective Multi-Center Analysis of Canine Socket Prostheses for Partial Limbs

Introduction: Socket prostheses for treatment of distal limb pathology are becoming increasingly prevalent in veterinary medicine, however, limited objective data is available. Objectives of the present study were to retrospectively evaluate owner satisfaction, clinical outcomes, and prognostic factors associated with dogs receiving socket prostheses for partial limbs in a larger patient population. Materials and Methods: Client databases of a single prosthesis provider were reviewed to identify owners whose dogs had received a prosthetic device within the last 10 years. An online survey was developed to evaluate owner-reported outcomes. The survey inquired about anatomy of the residuum, concurrent disease, prosthesis use, rehabilitation, activity, complications, and owner satisfaction. Medical records and radiographs were requested from all participants. Radiographs were used to confirm level of amputation and evaluate for osseous complications. Survey responses were analyzed by assigning author-defined numeric scores defining clinical outcome and owner satisfaction. Results: One-hundred thirty-seven owners were contacted. The response rate was 50/137 (37%); 47 responses were analyzed. Forty-six of 47 owners reported positive satisfaction; 1/47 was displeased. Forty-two of 47 dogs were scored to have acceptable to full function; 5/47 had unacceptable clinical function using the author-defined scoring system. A 62% short-term complication rate and a 19% long-term complication rate were reported. Skin sores were the most common short and long-term complication. There was a significant correlation between both clinical outcome scores and owner satisfaction with days per week spent in the prosthesis. Additionally, clinical outcome scores and owner satisfaction significantly varied between dogs with different durations of prosthesis wear with a trend toward better outcomes associated with longer prosthesis wear. Radiographs were obtained for 23/47 dogs to further define level of defect. The most proximal level of defect was mid-radius for the forelimb and mid-tibia for the hind limb. There was no correlation between level of defect and either owner satisfaction or clinical outcome. Discussion/Conclusion: Results of this survey suggest a high degree of owner satisfaction despite substantial complication rates. Based on preliminary data, further evaluation of socket prostheses as a limb-sparing option for treatment of distal limb pathology should be considered. Prospective clinical trials with objective outcome measures are required to draw firm conclusions.

Why Owners Choose an Orthosis Over Stifle Surgery for Canine Cranial Cruciate Ligament Deficiency

The objective of this study was to describe the patient population of dogs with cranial cruciate ligament (CrCL) deficiency that were prescribed a stifle orthosis. A total of 215 client-owned dogs with previously diagnosed CrCL deficiency were prescribed a stifle orthosis at a veterinary pain management and mobility clinic. Patient intake data collected included dog signalment, chief medical complaint, home environment and activity description, medical and surgical history, and diagnosing veterinarian. An orthopedic examination was conducted to assess pelvic limb function and determine pelvic limb morphologic measures. Spayed females (57.2%) were most common in our sample. Median age, body weight, and body condition score were 9.00 ± 3.23 years, 32.98 ± 13.37kg, and 6.00 ± 1.04, respectively. Most common breeds prescribed stifle orthoses included Labrador Retriever, Golden Retriever, and German Shepherd. Right and left limbs were equally affected, and 19.5% of dogs previously had stifle stabilization surgery. Primary reasons for seeking a stifle orthosis consultation were surgical concerns, advanced age, and surgery cost. Most common chief complaints included altered gait, decreased weight bearing, and pain following activity. Reduced stifle extension, increased cranial drawer score, and decreased 3-leg stance time characterized the CrCL-deficient stifle. Stifle orthosis represents an alternative approach to surgical stabilization and management of CrCL deficiency. CrCL-deficient dogs prescribed stifle orthoses were generally large breeds of advanced age with above ideal body condition score. Owners commonly sought a stifle orthosis for CrCL deficiency due to reservations regarding surgical management.

Pelvic limb kinematics in the dog with and without a stifle orthosis

OBJECTIVE

To report a method of evaluating 3-dimensional joint motion in dogs with a stifle orthosis.

STUDY DESIGN

Experimental.

ANIMALS

Six healthy dogs.

METHODS

Three-dimensional pelvic limb joint motion was recorded with and without a stifle orthosis. Kinematic data were collected from dogs at a walk and trot for the hip, stifle, and tarsus prior to, and after application of, a stifle orthosis. Data were also obtained for the orthosis alone. Comparisons were made between the braced and unbraced limb, and between the braced limb and the orthosis alone. Complete waveforms, kinematic, and temporospatial variables were compared.

RESULTS

Gait waveforms differed between braced and unbraced limbs for all joints and planes of motion (P < .05), as well as between the braced stifles and the orthosis alone at both a walk and trot. However, joint ROM was inconsistently altered. The effect of bracing on stifle ROM was limited to a reduced extension at the end of stance. Adjacent joint ROM was affected by the stifle orthosis. Temporospatial variables were predominantly affected while walking.

CONCLUSIONS

The restrictive motion of the stifle orthosis is not fully translated to the underlying joint, based on the limited differences between the motion of braced and unbraced stifles. This effect varies with plane of motion and phase of the gait cycle, with most changes in stifle motion being detected during the stance phase. The stifle orthosis had an equal or greater effect on the motion of adjacent joints, especially the tarsus.

Biomechanics of an orthosis-managed cranial cruciate ligament-deficient canine stifle joint predicted by use of a computer model

OBJECTIVE 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). SAMPLE A previously developed computer simulation model for a healthy 33-kg 5-year-old neutered Golden Retriever. PROCEDURES 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. RESULTS 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. CONCLUSIONS AND CLINICAL RELEVANCE 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.