Use of cannulated screws in the treatment of unicondylar humeral condylar fractures in dogs

OBJECTIVE

To describe unicondylar humeral fracture (UHF) repair using cannulated transcondylar screws, report postoperative fracture reduction, healing, and complication rates.

STUDY DESIGN

Retrospective.

ANIMALS

A total of 49 client owned dogs with UHF.

METHODS

Surgical technique and approach (i.e., open, limited open, or minimally invasive) were recorded. Articular step defect (ASD) and gap (Gap) at the humeral condylar articular surface were measured on pre- and postoperative images and reported as percentages. Fracture healing was graded on follow-up radiographs. Functional outcome was based on client questionnaire over the phone. General linear models were used to assess the impact of surgical approach on %ASD, %Gap, whereas Cox regression was used to assess prognostic factors of full fracture healing.

RESULTS

A total of 49 fractures repaired with a transcondylar screw with or without an antirotational pin(s) were included. Surgical approach did not have an impact on postoperative %ASD, %Gap or development of complications. The overall complication rate was 26% (11/42), with no revision surgery necessary. Of the dogs that encountered complications, 50% required pin and/or screw removal after fracture healing. For 29 dogs with a minimum of four-month owner telephone questionnaire follow-up, 90% reported no lameness and only three reported intermittent lameness. Achieving complete fracture healing was affected by increased postoperative %ASD (p = .033).

CONCLUSION

The UHFs repaired by transcondylar cannulated screws had acceptable outcomes and fracture reduction with complication rates being similar regardless of the surgical approach.

CLINICAL SIGNIFICANCE

Cannulated screws can be implanted with varying surgical approaches to successfully repair UHFs with comparable clinical outcome to previous reports.

Morphological and radiological study of the shoulder and elbow joints of the giant anteater (Myrmecophaga tridactyla)

The giant anteater (Myrmecophaga tridactyla) has specialized thoracic limbs to forage by breaking the walls of anthills and termite mounds. They also play critical roles in defense posture and locomotion. This study aimed to provide a morphological and radiographic description of the shoulder joint and elbow joint of the giant anteater. Both joints of 13 tamanduas were assessed by morphological dissections and histological evaluation and radiographies without and with positive contrast. The radiographic projections selected to this study were the mediolateral and craniocaudal projections. The radiographic and anatomical findings were compared with the following results: the shoulder joint had a continuous joint capsule with the tendon sheaths of the short head and long head of the biceps brachii muscle, which could be visualized with an injection of 3 ml of intra-articular contrast. The shoulder joint arthrography was performed with the needle positioned cranially to the joint for contrast injection. The elbow joint presented three articular compartments, and the insertion of the joint capsule was proximal to the radial fossa and distal to the radial tuberosity in the radial notch of the ulna, which were possible to identify with 2 ml of intra-articular contrast. The elbow joint arthrography was performed with the needle positioned laterally to the joint for contrast injection. Moreover, the joint capsule presented a caudomedial distention and fat pads. The powerful muscles of the forelimb play a fundamental role in maintaining the shoulder joint and elbow joint stability due to bony adaptations and the absence of usual ligaments. The morphological and radiological study provided relevant information on the soft-tissue characteristics of shoulder and elbow joints, which may aid clinical-surgical and diagnostic imaging procedures.

Moving Beyond the Limits of Detection: The Past, the Present, and the Future of Diagnostic Imaging in Canine Osteoarthritis

Osteoarthritis (OA) is the most common orthopedic condition in dogs, characterized as the chronic, painful end-point of a synovial joint with limited therapeutic options other than palliative pain control or surgical salvage. Since the 1970s, radiography has been the standard-of-care for the imaging diagnosis of OA, despite its known limitations. As newer technologies have been developed, the limits of detection have lowered, allowing for the identification of earlier stages of OA. Identification of OA at a stage where it is potentially reversible still remains elusive, however, yet there is hope that newer technologies may be able to close this gap. In this article, we review the changes in the imaging of canine OA over the past 50 years and give a speculative view on future innovations which may provide for earlier identification, with the ultimate goal of repositioning the limit of detection to cross the threshold of this potentially reversible disease.

Anionic Contrast-Enhanced MicroCT Imaging Correlates with Biochemical and Histological Evaluations of Osteoarthritic Articular Cartilage

This study addressed difficulties in evaluating osteoarthritis (OA) progression in species with thin cartilage. Feasibility of using short, nonequilibrium contrast-enhanced micro-computed tomography (CE-μCT) to evaluate the physical and biochemical properties of cartilage was investigated. A preliminary in vitro study using CE-μCT study was performed using bovine osteochondral blocks with intact, mildly damaged (fibrillated), or severely damaged (delaminated) cartilage. Delamination of the superficial zone resulted in elevated apparent density compared with intact cartilage after 10 minutes of anionic contrast exposure (P < 0.01). OA was induced by unilateral meniscal destabilization in n = 20 sheep divided into: early phase OA (n = 9) and late phase OA (n = 11), while n = 4 remained as naive controls. In vivo anionic nonequilibrium contrast CT of the operated stifle was conducted in the early phase sheep 13 weeks postoperatively using clinical resolution CT. Cartilage visibility in the contrasted leg was significantly improved compared with the noncontrasted contralateral stifle (P < 0.05). Animals were sacrificed at 3 months (early phase) or 12 months (late phase) for additional ex vivo CE-μCT, and correlative tests with biochemical and histological measures. Concentration of sulfated glycosaminoglycan (sGAG) significantly varied between control, early, and late phase OA (P < 0.005) and showed a negative (r = -0.56) relationship with apparent density in the medial tibial plateau (R2 = 0.28, P < 0.001). Histologically, parameters in proteoglycan and cartilage surface structure correlated with increasing attenuation. While previous studies have shown that CE-CT increases the apparent density of proteoglycan-depleted cartilage, we concluded that superficial zone disruption also contributes to this phenomenon.

Contrast Enhanced Computed Tomography Findings in 105 Horse Distal Extremities

The poor soft tissue conspicuity of CT can be improved by using intra-arterial CT Angiography (CTA), and intra-articular and intra-bursal contrast enhanced CT (CTAR). This retrospective study describes a combination protocol of CT and CTA of the horse's foot, and CTAR of the distal interphalangeal joint and navicular bursa. It is hypothesized this would provide a comprehensive overview of the range and severity of distal limb pathology. Radiology reports of all horses admitted for distal limb CT over a 5 year period were reviewed. All horses with a complete four stage CT examination and radiology report with lameness isolated to the foot were included. Twenty seven imaging findings using a four grade semiquantitative severity scoring system contributing towards six main diagnostic categories were described. One hundred and five examinations on 56 horses revealed a diagnosis of navicular bone disease in 64%, deep digital flexor tendinopathy in 43%, distal interphalangeal osteoarthritis in 35%, navicular bursitis in 31%, distal interphalangeal collateral ligament desmopathy in 26%, and hoof capsule and distal phalanx pathology in 10%. Only 25% of the navicular bone disease cases were considered clinically significant. The majority of deep digital flexor tendon lesions (77%) and distal interphalangeal joint osteoarthritis (51%) were considered significant. Approximately one third of navicular bursa (37%) and collateral ligament (33%) abnormalities were considered significant. Navicular bursa abnormalities were associated with navicular bone and deep digital flexor tendon lesions. The findings support the hypothesis and the use of this protocol for evaluation of foot lameness.