Evaluation of a distractor to increase joint space of the stifle joint in dogs: a cadaveric study.

OBJECTIVE: To evaluate the technical feasibility and efficacy of a joint distraction technique to increase the stifle joint space and assess potential soft tissue damage due to the distraction. METHODS: Twenty stifle joints of twelve canine cadavers without evidence of disease were radiographically evaluated by medio-lateral, cranio-caudal and varus-valgus stressed projections. Joint distraction was applied with loads from 40 N up to 200 N, and the joint space achieved was measured on radiographic images. Distraction plus distension with saline was subsequently applied and measured. Varus-valgus stressed projections were repeated after distraction to evaluate a potential increase in joint laxity. RESULTS: Distraction produced a significant increase of the joint space for most of the evaluated loads. Distraction plus distension produced a significant increase for most of the loads compared to the distraction alone. No ensuing joint laxity could be inferred from the post-distraction radiographic evaluation. CLINICAL SIGNIFICANCE: Stifle distraction produces an increase of the joint space, which is wider when intra-articular saline is injected. This may be potentially useful for improving joint structure visualization and facilitating arthroscopic procedures, thus reducing the potential for iatrogenic damage to intra-articular structures. No soft tissue damage could be inferred by radiographic pre- and post-procedure comparison. Further clinical studies are required to evaluate potential neurovascular complications.

Evaluation of traction stirrup distraction technique to increase the joint space of the shoulder joint in the dog: A cadaveric study.

The objective of this study was to evaluate technical feasibility and efficacy of a joint distraction technique by traction stirrup to facilitate shoulder arthroscopy and assess potential soft tissue damage. Twenty shoulders were evaluated radiographically before distraction. Distraction was applied with loads from 40 N up to 200 N, in 40 N increments, and the joint space was recorded at each step by radiographic images. The effects of joint flexion and intra-articular air injection at maximum load were evaluated. Radiographic evaluation was performed after distraction to evaluate ensuing joint laxity. Joint distraction by traction stirrup technique produces a significant increase in the joint space; an increase in joint laxity could not be inferred by standard and stress radiographs. However, further clinical studies are required to evaluate potential neurovascular complications. A wider joint space may be useful to facilitate arthroscopy, reducing the likelihood for iatrogenic damage to intra-articular structures.

Evaluation of a joint distractor to facilitate arthroscopy of the hip joint in dogs.

OBJECTIVE: To evaluate the technical feasibility and efficacy of a hip joint distraction technique, any potential ligamentous damage linked to the procedure, and the effect of joint venting on the maximum distraction achieved. METHODS: Twenty hip joints from 11 canine cadavers were evaluated radiographically by standard and stressed projections. Joint distraction was applied with loads from 40 up to 200 N, in 40 N increments, and fluoroscopic images were obtained at each load. At 200 N, a needle was inserted into the joint to achieve a venting effect, and the space was measured again. Standard and stressed radiographs were performed to evaluate potential laxity changes. RESULTS: Distraction caused a significant increase in joint space at each load of distraction, although there were some variations. Joint venting produced a significant increase in joint space. A statistically significant difference in joint laxity evaluated radiographically before and after the procedure was recorded. CLINICAL SIGNIFICANCE: Use of the distraction apparatus resulted in an increase in joint space. This could be useful for clinical situations where a larger joint space is required such as for arthroscopic procedures. However, loads in excess of 200 N may induce significant increases in joint laxity.

Comparison of the axial stiffness of carbon composite and aluminium alloy circular external skeletal fixator rings.

OBJECTIVES: The purpose of this study was to compare the axial stiffness of aluminium alloy and carbon composite single-ring constructs. METHODS: Single-ring constructs were made with rings of different material compositions (aluminium alloy and carbon composite), diameters (55 mm, 85 mm, and 115 mm), and thicknesses (6 mm for the single-ring, 12 mm for the double-ring) with all other components remaining constant. Stiffness of each construct was determined under loading in axial compression with a materials testing machine. The axial stiffness of each group was compared using a three-factor factorial analysis of variance investigating all main effects and interactions between ring diameter, ring thickness, and ring material composition; p <0.05 was considered significant. RESULTS: Carbon composite constructs were 16-55% as stiff as corresponding aluminium alloy constructs. Within each combination of ring material composition and ring diameter, stiffness did not significantly increase when the ring thickness was doubled. Within each combination of ring material composition and ring thickness, stiffness significantly decreased with increased ring diameter. CLINICAL SIGNIFICANCE: Aluminium alloy rings were found to be significantly stiffer than carbon composite rings. Although the carbon composite rings were considerably less stiff, clinical recommendations cannot be made from a single-ring in vitro analysis. Further studies are needed to evaluate the behaviour of these rings in vivo.

Biomechanical comparison of strategies to adjust axial stiffness of a hybrid fixator.

OBJECTIVES: To evaluate strategies for increasing the axial stiffness of a hybrid external bone fixator. MATERIALS AND METHODS: Type Ia hybrid fixators, consisting of a uniplanar linear component connected to a circular ring, were tested in displacement controlled loading in axial compression. The basic hybrid construct was modified to explore strategies considered to increase fixator stiffness including: decreasing ring diameter, increasing ring thickness, adding pins to the ring fixation, and adding struts between the ring and vertical post components of the device. Stiffness in the initial phase of loading was compared between the groups. RESULTS: The addition of a single diagonal bar between the ring and linear connecting rail did not significantly improve the stiffness of constructs. However, the addition of two half-pins to the ring, the addition of two struts between the ring and linear connecting rail, or decreasing the internal ring diameter from 115 to 85 mm progressively increased the stiffness of the frame. The most effective strategy consisted of increasing the thickness of the ring from 6 to 12 mm, thereby increasing the stiffness of the control frame by 335%. CLINICAL SIGNIFICANCE: Modulating the ring thickness, adding two struts between the ring and linear connecting rail, and reducing the ring diameter appear to be the most effective, simple, and clinically versatile ways to increase axial stiffness, most likely due to their impact on reducing ring bending.

Management of 49 antebrachial and crural fractures in dogs using circular external fixators.

OBJECTIVES: To evaluate frame constructs, postoperative fracture reduction, postoperative care, complications, treatment duration and outcome of circular external fixation for management of 49 antebrachial and crural fractures in dogs. METHODS: Medical records of dogs that underwent surgery with circular external fixation were examined for fracture location, frame configuration, postoperative fracture reduction, treatment duration, complications and outcome. RESULTS: Forty-nine fractures in 48 dogs were stabilised using circular external fixation. Frame removal occurred on average 61 days after surgery (median+/-sd, 52+/-30 days). Minor complications were observed in 35 cases (71 per cent) and major complications in seven (14 per cent). Radiographic outcome at frame removal was judged as excellent in 18 cases (37 per cent), as good in 26 (53 per cent), as fair in four (8 per cent) and poor in one (2 per cent). After frame removal, one fracture was stabilised with a plate, and eight patients were lost to follow-up. Functional and cosmetic outcome at follow-up was judged as excellent in 32 cases (80 per cent), good in seven (18 per cent) and fair in one (2 per cent). CLINICAL SIGNIFICANCE: Circular external fixation can effectively treat antebrachial and crural fractures in dogs, even geometrically complex fractures. Minor complications are frequent but easily managed in most instances. Healing time is comparable to that of other external fixation methods.

Intraoperative skeletal traction in the dog: a cadaveric study.

A standard skeletal traction technique was applied to each major segment of the appendicular skeleton of ten fresh dog cadavers. Opposition points and anchorage points for the application of traction were determined for each skeletal segment. Traction was exerted by means of a micrometric traction stand, connected to the limb by bands or a stirrup. Traction was applied to the antebrachium and the tibia through nylon traction bands anchored to the metacarpus and metatarsus, respectively. A traction stirrup applied to the condylar region was used as the anchorage point to load the humerus and femur. Once a peak force of 25 kg weight was achieved, the load was monitored for half an hour to check for any variation. After that, each skeletal segment was osteotomized in the mid-diaphyseal region, and evaluated for any angular malalignment due to a mismatch between the axis of the bone and the applied loading. Any ensuing angular malalignment was successfully corrected by manoeuvres using the traction stand. The technique used in this study to perform intraoperative skeletal traction proved to be reliable and consistent for each segment of the appendicular skeleton.

Clinical application of intraoperative skeletal traction in the dog.

The purpose of this clinical study was to evaluate the technical feasibility of a method for pre-operative and intra-operative traction for reduction of fractures of the appendicular skeleton. Traction was used in 24 diaphyseal fractures in 21 dogs. For each dog, the data pertaining to signalment, limb circumference, fracture type, interval between fracture and surgery, and the traction modalities were recorded. In patients with a latency between trauma and surgery of less than three days, the duration of traction required to realign the bone segments was shorter than that required for older fractures (P = 0.02). Intraoperative malalignments were corrected by manoeuvres performed with the traction stand. Once realigned, fracture segments were kept stable for prolonged periods, without the need for a surgical assistant. Postoperative radiographs were evaluated for fracture reduction and axial alignment. Postoperative alignment was judged excellent in 21 fractures and good in three fractures. Fractures were stabilized using external skeletal fixation (n = 10), plates (n = 11) or locked nails (n = 3), depending on the fracture type. The use of the technique was straight-forward and easily applied in a surgical setting. However, its use requires careful application because of the potential for iatrogenic tissue damage.

Suspected latent vertebral metastasis of uveal melanoma in a dog: a case report.

A six-year-old intact male Pomeranian was examined because of right eye discomfort. An iris neoplasm was suspected and the eye was enucleated. A uveal melanoma with malignant features was diagnosed. The dog recovered uneventfully from surgery. A general physical examination was performed at 3-month intervals afterwards without any detectable problem, but 18 months after the first presentation the dog suffered a rapid, progressive paraplegia. Radiographic examination and myelography revealed a spinal cord compression at the level of the 8th thoracic (T8) vertebral body. Surgical exploration of the area revealed a potential vertebral neoplasm: histopathology confirmed a melanoma which was suspected to have resulted from metastasis from the previously diagnosed uveal melanoma.

Fragmented coronoid process and incomplete ossification of the humeral condyle in a rottweiler.

OBJECTIVE: To describe incomplete ossification of the humeral condyle and fragmentation of the medial coronoid process in a Rottweiler. STUDY DESIGN: Clinical report. ANIMAL POPULATION: A 4-year-old sexually intact male Rottweiler. METHODS: Physical examination, radiography, and computed tomography of both elbow joints were performed initially. Drill holes were made across the humeral condyle to promote ossification. Radiography and computed tomography were repeated 14 weeks later. Radiography was repeated 15 months later. A mild intermittent lameness remained. RESULTS: Preoperatively a radiolucent line was present across the right humeral condyle. This radiolucent line remained unchanged 14 weeks after drill holes were made across the condyle. CONCLUSIONS: Incomplete ossification of the humeral condyle is present in Rottweilers. CLINICAL RELEVANCE: Incomplete ossification of the humeral condyle is present in Rottweilers and may coexist with fragmentation of the medial coronoid process in that breed. The radiographic diagnosis may be difficult because precise positioning is required to see the area of incomplete ossification. Computed tomography may be required to confirm the presence of incomplete ossification of the humeral condyle. Drilling holes across the humeral condyle does not appear to lead to union of the area of incomplete ossification.