Micro-CT Structural Analysis of the Canine Medial Coronoid Disease

Osteoarthritis, adipokines and the translational research potential in small animal patients

Osteoartritis (OA) is a debilitating disease affecting both humans and animals. In the early stages, OA is characterized by damage to the extracellular matrix (ECM) and apoptosis and depletion of chondrocytes. OA progression is characterized by hyaline cartilage loss, chondrophyte and osteophyte formation, thickening of the joint capsule and function loss in the later stages. As the regenerative potential of cartilage is very limited and osteoarthritic changes are irreversible, prevention of OA, modulation of existing osteoarthritic joint inflammation, reducing joint pain and supporting joint function are the only options. Progression of OA and pain may necessitate surgical intervention with joint replacement or arthrodesis as end-stage procedures. In human medicine, the role of adipokines in the development and progression of OA has received increasing interest. At present, the known adipokines include leptin, adiponectin, visfatin, resistin, progranulin, chemerin, lipocalin-2, vaspin, omentin-1 and nesfatin. Adipokines have been demonstrated to play a pivotal role in joint homeostasis by modulating anabolic and catabolic balance, autophagy, apoptosis and inflammatory responses. In small animals, in terms of dogs and cats, naturally occurring OA has been clearly demonstrated as a clinical problem. Similar to humans, the etiology of OA is multifactorial and has not been fully elucidated. Humans, dogs and cats share many joint related degenerative diseases leading to OA. In this review, joint homeostasis, OA, adipokines and the most common joint diseases in small animals leading to naturally occurring OA and their relation with adipokines are discussed. The purpose of this review is highlighting the translational potential of OA and adipokines research in small animal patients.

The use of lateral arthroscopy portals for the management of a fragmented lateral coronoid process in an English Bulldog

OBJECTIVE

To report a case of unilateral lateral coronoid process fragmentation in a dog treated via lateral elbow arthroscopy portals.

ANIMAL

A 9-month old male intact English Bulldog.

STUDY DESIGN

Case report.

METHODS

The dog presented with a history of intermittent right thoracic limb lameness. Orthopedic examination on presentation was unremarkable. Computed tomography of the right thoracic limb was pursued and revealed a mineralized focus along the lateral margin of the lateral coronoid process as well as sclerosis of the medial coronoid process and subtrochlear region of the ulna. Elbow arthroscopy was performed via a lateral approach and revealed chondromalacia of the entire lateral coronoid process. Abrasion arthroplasty of the lateral coronoid process was performed.

RESULTS

Complete resolution of the lameness was achieved within two weeks of surgery. At 6 weeks postoperatively, the dog remained sound and a gradual return to normal activity was recommended. At the final follow up assessment, 5 months after surgery, no abnormalities were found on orthopedic examination and the owners reported excellent limb function with no observable lameness.

CONCLUSION

Lateral coronoid disease can occur as a rare component of elbow dysplasia in dogs. Abrasion arthroplasty via lateral arthroscopic portals may have resulted in a successful outcome in this case and may form an effective treatment option for lateral coronoid disease in dogs.

Microcomputed tomographic analysis of the ulnar trochlear notch in medium- and large-breed canine cadavers with and without medial coronoid disease

Medial coronoid disease (MCD) is a common disease often associated with thoracic limb lameness in medium- and large-breed dogs. The term MCD includes subchondral changes of the medial coronoid process (MCP), as well as pathologies of both cartilaginous surfaces. As there are only a few comprehensive and detailed studies on the trabecular structure of the medial coronoid, the goal of this study was to compare the trabecular structure of the ulnar trochlear notch of canine cadavers with and without MCD using different micro-computed tomographic (micro-CT) parameters. Fifty-eight elbow joints from 29 canine cadavers of MCD-predisposed and non-predisposed breeds (control group) were examined radiographically, macroscopically and by microcomputed tomography. The study included elbow joints of eight Labrador Retrievers (21.6-37 kg), seven Golden Retrievers (26.3-42 kg), seven Bernese Mountain dogs (31-47 kg) and seven dogs of non-predisposed breeds (19.7-52 kg) (control group). The final diagnosis of MCD was based on necropsy and micro-computed tomographic examinations. Micro-CT examinations were performed using XtremeCT II (Scanco Medical, Zurich, Switzerland) and the following parameters were examined: bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular number (Tb.N), connectivity density (Conn.D) and degree of anisotropy (DA). Twenty-four elbows of 44 elbows of the predisposed breeds (Labrador Retrievers, Golden Retrievers Bernese Mountain dogs) showed subchondral changes and lesions of the cartilage surfaces. The result of this study is a higher density (BV/TV) of the trabecular bone of the ulnar trochlear notch in elbows affected by MCD compared to the control group. The increased density due to trabecular reconstruction in the ulnar trochlear notch is likely the result of selectively increased loading during life.

Review of minimally invasive surgical procedures for assessment and treatment of medial coronoid process disease

OBJECTIVE

To summarize the current peer-reviewed publications on minimally invasive surgery (MIS) for medial coronoid process disease (MCPD) in dogs.

STUDY DESIGN

Invited review.

METHODS

Pubmed, CAB Abstracts and Scopus databases were utilized for literature review (1990-2023).

RESULTS

More than 60 papers have been published that involve MIS evaluation or treatment of MCPD. Six prospective trials incorporated quantitative gait analysis evaluating outcome following MCPD debridement, of which three included a control group. Whilst case numbers were limited, all studies employing a control group failed to demonstrate superiority of surgery over nonsurgical management. Of three studies employing gait analysis and no control group, all documented some improvement in function compared to pretreatment lameness. Multiple studies document progression of osteoarthritis in dogs following MCPD debridement although this may not be synonymous with worsened function. Subtotal coronoid osteotomy (SCO) is described as an alternative to MCP fragment removal, although the long-term biomechanical consequences are currently unclear and quantitative data on the efficacy of this treatment in isolation for MCPD is awaited.

CONCLUSION

Arthroscopy of the canine elbow joint is a safe means by which to evaluate MCP pathology. Quantitative longitudinal analysis of outcome following minimally invasive surgery for MCPD is required. Correlation with clearly defined subclassification inclusion criteria such as age, incongruity and the precise arthroscopic findings in each case are required to more accurately differentiate any superiority of surgery over nonsurgical management for this disease.

Effect Of Elbow Angle And Weight-Bearing On The Evaluation Of Joint Congruence In Dogs

Joint congruence is relevant for the assessment of elbow dysplasia, a development disorder in dogs. However, quantification of its variation with joint angle and weight bearing, important factors in quadrupedal locomotion, is lacking. Our objective was to estimate those effects on the alignment of humeroradioulnar joint surfaces. The usual protocol for screening elbow dysplasia, including mediolateral extended and flexed elbow views, was preceded by a weight-bearing lateromedial standing radiographic view, without sedation. Minimum distances were measured at established points of the humeroradioulnar joints classified with a grade zero of dysplasia. Sixty elbows (30 Portuguese Pointer dogs) were studied. The joint space between the anconeal process and the ulnar trochlear notch increased with flexion, decreasing with weight bearing (P<0.001). The distance between the humeral trochlea and the trochlear notch at the widest point, increased with weight bearing, while it decreased with flexion. Step and distance between the radial head and the base of the medial coronoid process increased with flexion and decreased with weight bearing. At this point, physiological changes occurred at the humeroulnar joint space. The methodology allowed to quantify the variations on joint spaces with the elbow angle and weight bearing, important for the interpretation of congruence in diagnosis and treatment of dysplasia. Reference absolute and indexed values obtained allow future comparisons with other breeds and dysplastic dogs. Physiological variations denoted that radioulnar joint became more incongruent under flexion, and more congruent under weight bearing, while humeroulnar joint became more congruent under flexion, and more incongruent under weight bearing.

Proximal Abduction Ulnar Osteotomy (PAUL): Short- and Long-Term Evaluation in Dogs Presenting Medial Compartment Disease

Simple Summary

Developmental elbow disease is one of the main causes of lameness in the canine species and occurs often in large and giant breed dogs. The most frequent manifestation of this pathology is known as medial compartment disease due to a physiological overload in the medial region of the elbow. It is considered as a complex disease and the treatment is focused on relieving the pain and slowing the progression of osteoarthritis. The Proximal Abduction Ulnar Osteotomy (PAUL) technique is one of the newest techniques whose purpose is the transmission of loads from the medial to the lateral compartment. In this prospective case series, the authors use the combination of elbow arthroscopy and the PAUL technique and report a significant improvement in clinical signs, showing a low major complications rate with a high degree of owner satisfaction.

Abstract

The aim of the study is to report the results obtained from performing a Proximal Abduction Ulnar Osteotomy (PAUL) technique in a cohort of dogs with medial compartment disease with short- and long-term follow-up, assessing the perception of the owners and describing the long-term complications associated with the technique. This is a clinical prospective study, including dogs diagnosed with medial compartment disease treated with elbow arthroscopy and PAUL between 2013 and 2020. Long-term follow-up data and postoperative complications were registered, and a questionnaire adapted from Fitzpatrick et al. 2009 was collected from owners. Thirty-three elbows in 26 dogs were included. The duration of follow-up ranged from 4 to 61 months (median: 24.76 months). At the end of the study, 73.1% of the owners reported excellent satisfaction and 74.1% of the owners would repeat the surgery in the same circumstances. The owner questionnaire showed a greater capacity to walk and run, without lameness and pain, and climb up and down stairs a year after surgery, being constant at the end of the study. Major postoperative complications were documented in 4/33 elbows (12.12%), including delayed union, implant failure, and osteophytosis of the medial aspect of the coronoid process. In conclusion, elbow arthroscopy and the PAUL technique achieved an evident improvement in the quality of life of patients with great satisfaction for most of the owners.

Biomechanics of the Canine Elbow Joint

The canine elbow joint is a complex joint, whose musculoskeletal anatomy is well investigated. During the last 30 years kinematic analysis has gained importance in veterinary research and kinematics of the healthy and medial coronoid disease affected canine elbow joint are progressively investigated. Video-kinematographic analysis represents the most commonly used technique and multiple studies have investigated the range of motion, angular velocity, duration of swing and stance phase, stride length and other kinematic parameters, mostly in the sagittal plane only. However, this technique is more error-prone and data gained by video-kinematography represent the kinematics of the whole limb including the soft tissue envelope. A more precise evaluation of the in vivo bone and joint movement can only been achieved using fluoroscopic kinematography. Based on recent studies significant differences in the motion pattern between healthy joints and elbows with medial coronoid disease could be detected. Thereby not only adaptive changes, caused by pain and lameness, could be described, but primary changes in the micromotion of the joint forming bones could be found, which potentially represent new factors in the pathogenesis of medial coronoid disease. This chapter gives a review of current literature on elbow joint kinematics, with particular focus onto pathologic biomechanics in dysplastic canine elbows.

The cat as a small dog?-Comparison of trabecular and cortical bone microarchitecture of radius and ulna in cats and small dogs using microcomputed tomography

The forearms of dogs and cats do not only differ anatomically from each other, but there are also differences in prevalence of radius and ulna fractures between the two species. The prevalence of antebrachial fractures is 18.0% in dogs and 2.0–8.0% in cats. Many studies focus solely on the trabecular and cortical bone structure of dogs and the characteristics of the cat are often disregarded.

The aim of this study was to evaluate the trabecular structure parameters [bone volume fraction per total volume (BV/TV), bone surface per total volume (BS/BV), trabecular number (Tb.N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), connectivity density (Conn. D), degree of anisotropy (DA)] and the diaphyseal cortical bone density (Mean Density) of the antebrachium in cats and small dogs to visualise their differences.

For this purpose, a total of 32 forearms of cats (n = 8) and small dogs (n = 8) were evaluated using microcomputed tomography and the findings were compared.

The results of the study showed that cats had higher values for BV/TV, Tb.Th, Tb.Sp, DA and Mean Density and lower values for BS/BV, Tb.N and Conn.D at radius and ulna compared to dogs.

According to the results of this study, the higher bone volume fraction (BV/TV), thicker trabeculae (Tb.Th), increased anisotropy (DA) and significantly higher diaphyseal cortical density (Mean Density) could contribute to the lower fracture risk of the antebrachium in cats compared to small dogs.

Relation of Computed Tomography-Based Static Axial Radioulnar Incongruence Measurements under General Anaesthesia and Dynamic, In Vivo RUI during the Walk in Canine Elbow Joints with and without Medial Coronoid Process Disease

OBJECTIVE

 This study aimed to evaluate the correlation of static axial radioulnar incongruence (sRUI) measured under general anaesthesia with the real in vivo dynamic RUI (dRUI) during walking.

STUDY DESIGN

 This was a prospective clinical study that included 6 sound elbows (5 dogs) and 7 medial coronoid process disease (MCPD) affected elbows (6 dogs).

MATERIALS AND METHODS

 Static axial radioulnar incongruence was measured using the sphere fitting technique on computed tomography-based three-dimensional (3D) models of radius and ulna. The in vivo pose of radius and ulna was derived from radiostereometric analysis during the walk and transferred onto previously calculated 3D models. Dynamic RUI was measured on those adjusted models using the sphere fitting technique, providing a measurement of RUI over time during walk.

RESULTS

 Mean sRUI was 0.2 mm (standard deviation [SD]: 0.30) in control and 1.4 mm (SD: 0.73) in elbow joints with MCPD; being significantly different (p = 0.0035; confidence interval [CI]: 0.4772-1.8824). Mean dRUI in controls (-0.4 mm; SD: 0.47) was significantly different (p = 0.0004; CI: 0.9918-2.5225) from dRUI in the affected elbows (1.4 mm; SD: 0.73). Comparison of sRUI and dRUI within each group showed difference in the control group (0.2 vs. -0.4 mm; p = 0.0138; CI: 0.1820-1.0014). In affected elbows, no difference between sRUI and dRUI was found (1.4 vs. 1.4 mm; p = 0.8963).

CONCLUSION

 In normal elbow joints, sRUI does not represent the in vivo condition during weight bearing. Dynamic and slightly negative RUI occurs during loading (0.2 mm positive to -0.4 mm negative RUI). In MCPD affected elbows with sRUI, no dynamic change of RUI occurs during the walk.

Comparative microcomputed tomographic structural analysis of the trabecular and cortical bone architecture of radius and ulna in toy dog breeds

Radius and ulna fractures can be detected in dogs with an incidence of 18.0% and occur more frequently in toy breeds with increased complication rates. The reasons for the predisposition and the increased complication rate of antebrachial fractures in toy breeds are not yet fully understood. The aim of this study was to research the associated mechanisms by investigating the trabecular structure parameters (BV/TV (%), Tb.N (mm^-1), Tb.Th (mm), Tb.Sp (mm), Conn. D (mm^-3), DA) and the cortical bone density (Mean Density (mg HA/ccm)) for toy breeds and small dogs of other breeds using microcomputed tomography and to identify the differences between both groups. A total of 70 forearms, originating from toy breeds (n = 36) and small dogs of other breeds (n = 34) were evaluated by microcomputed tomography. The results of this study showed a lower bone volume fraction (BV/TV), more (Tb.N) but thinner trabeculae (Tb.Th) with greater separation (Tb.Sp) and decreased diaphyseal cortical density (Mean Density) in toy breed dogs. This could thus contribute to the increased risk of antebrachial fractures in toy breeds. Within the group of toy breeds inhomogeneous results were observed, whereby the values of the Chihuahuas deviated. This breed had significantly thinner trabeculae (Tb.Th) with a greater trabecular separation (Tb.Sp), lower bone volume fraction (BV/TV) and significantly lower diaphyseal cortical density (Mean Density). These parameters could therefore indicate an increased antebrachial fracture and complication risk, especially in Chihuahuas.

Mid- to Long-Term Outcome after Arthroscopy and Proximal Abducting Ulnar Osteotomy Versus Arthroscopy Alone in Dogs with Medial Compartment Disease: Thirty Cases

OBJECTIVE

 The aim of this study was to determine owner-assessed mid- to long-term outcome for dogs with medial compartment disease treated arthroscopically with fragment removal with or without proximal abducting ulnar osteotomy (PAUL).

STUDY DESIGN

 This was a retrospective clinical study.

MATERIALS AND METHODS

 Records from 30 dogs with medial compartment disease treated with arthroscopy with or without PAUL were retrospectively reviewed over a 5-year period. Proximal abducting ulnar osteotomy cases were matched to arthroscopy-alone controls based on bodyweight and modified Outerbridge score. Outcome was assessed via owner questionnaire using the Canine Brief Pain Inventory (CBPI), frequency of non-steroidal anti-inflammatory drug (NSAID) administration and owner-assessed overall improvement.

RESULTS

 Canine Brief Pain Inventory score for dogs in the PAUL group was not significantly different from the control group (p = 0.54). Non-steroidal anti-inflammatory drug administration was similar between groups (p = 0.61) and there was no significant difference between modified Outerbridge score and outcome (p = 0.57) over a median of 43 months post-surgically (range: 7-66 months). Canine Brief Pain Inventory and NSAID use were affected by the age of the dog with dogs greater than 3 years of age at the time of surgery having a higher CBPI score and increased NSAID use regardless of the surgery that was performed. Overall, owner-assessed improvement was not different between groups (p = 0.72).

CLINICAL SIGNIFICANCE

 Proximal abducting ulnar osteotomy showed no owner-assessed benefit over arthroscopic medial coronoid fragment removal for dogs with medial compartment disease and modified Outerbridge score of 3 or greater. A prospective, blinded, controlled clinical trial is warranted to determine the appropriate clinical application of the PAUL procedure.

Force Distribution in the Canine Proximal Radio-Ulnar Joint on Extension of the Carpal Joint: A Cadaveric Study

OBJECTIVE

 The aim of this study was to measure the load on the lateral and medial aspects of the proximal radio-ulnar joint during extension of the carpus.

STUDY DESIGN

 This was an ex vivo biomechanical study.

SAMPLE POPULATION

 Twenty-two cadaveric Greyhound thoracic limbs were used.

METHODS

 Twenty-two paired thoracic limbs were used. The olecranon was attached to a custom jig with the foot resting on a stationary anvil. Load sensors were inserted into the proximal radio-ulnar joint, between the radial head and the lateral coronoid process, and between the radial head and the medial coronoid process. Specimens were tested under compression with measurements taken at 0, 4, 9 and 13.5 mm of axial displacement. Data collected at each point included forces on the specimen and medial and lateral coronoid processes as well as the angle of carpal joint extension.

RESULTS

 A linear mixed effects model relating load on the specimen and carpal joint extension angle had an R-squared value of 0.66, and load at the level of the medial coronoid process and angle of carpal extension had an R-squared value of 0.61. There was a significant difference in the loads measured on the lateral and medial coronoid processes at all angles (p < 0.0001).

CONCLUSION

 Extension of the carpus results in asymmetric loading of the proximal radio-ulnar joint.

CLINICAL SIGNIFICANCE

 The findings of this study show that loading of the medial coronoid process may be more complex than originally thought and supports the future investigation of novel management and therapeutic options for affected patients.

Diagnostic Yield of Micro-Computed Tomography (micro-CT) Versus Histopathology of a Canine Oral Fibrosarcoma

Micro-computed tomography (micro-CT) imaging currently gains increased interest in human as well as veterinary medicine. The ability to image 3-dimensional (3D) biopsy specimens nondestructively down to 1 µm spatial resolution makes it a promising tool for microscopic tissue evaluation in addition to histopathology. Visualizing tumor margins and calculating tumor load on 3D reconstructions may also enhance oncological therapies. The objective of this study was to describe the workflow from tumor resection to histopathological diagnosis, using both routine hematoxylin-eosin (HE)-stained sections and micro-CT tomograms on a stage II oral fibrosarcoma in a 7-year-old Hovawart dog. The maxillectomy specimen was fixed with formalin and stained with an X-ray dense soft tissue contrast agent. Micro-CT imaging was done using an ex vivo specimen micro-CT device. Tumor margins could not be exactly determined on micro-CT tomograms due to limited image resolution and contrast. Histopathology was performed after washing out the contrast agent. It showed neoplastic cells infiltrating the surrounding tissue further than assumed from micro-CT images. A total tumor volume of 10.3 cm³ could be calculated based on correlating micro-CT tomograms with HE-stained sections. This correlative approach may be of particular interest for oncological therapy. More than that, micro-CT imaging technology supported histopathology by means of 3D orientation and selection of slices to be cut on determining tumor margins. In this clinical case report, micro-CT imaging did not provide unambiguous clinical evidence for oncological decision-making, but it showed potential to support histopathology and calculate tumor volume for further clinical use.

Radial torsion in dogs with medial compartment disease

OBJECTIVE

To evaluate the magnitude and direction of radial torsion (RT) in dogs with medial compartment disease (MCD).

STUDY DESIGN

Case-control study.

SAMPLE POPULATION

Twenty-eight healthy dogs and 28 dogs with confirmed MCD.

METHODS

Computed tomography images of each dog's antebrachium were evaluated. Radial torsion was measured by using previously described landmarks on the proximal and distal radius. Differences between groups were tested with Student's t tests and Wilcoxon rank-sum tests.

RESULTS

Healthy dogs had a mean RT angle of 3.44° (range, 1.28°-5.44°). Dogs with MCD had a mean RT angle of 11.84° (range, 2.31°-26.55°). Both groups included similar proportions of dogs with external (76% vs 77%) and internal (24% vs 23%) torsion. The direction of torsion (P = .21 and P = .69) did not appear to affect the magnitude of the RT angle.

CONCLUSION

Dogs with MCD had an increased RT angle compared with healthy controls. The direction of torsion varied similarly between groups regardless of the disease status of dogs in this study.

CLINICAL SIGNIFICANCE

The fourfold increase in the RT seen in dogs with MCD may contribute to the rotational overload proposed recently, potentially modifying the orientation of the elliptical radial head and the ligaments crossing the elbow joint.

In vivo fluoroscopic kinematography of dynamic radio-ulnar incongruence in dogs

Aim of the study was to investigate dynamic radio-ulnar incongruence (dRUI) in the canine elbow joint comparing orthopedic healthy and dysplastic dogs in a prospective in vivo study design. In 6 orthopedic sound elbow joints (5 dogs, median age 17 months & mean body weight 27.9 kg) and 7 elbow joints with medial coronoid disease (6 dogs, median age 17.5 months & mean body weight 27.6 kg) 0.8 mm Ø tantalum beads were surgically implanted into radius, ulna and humerus for dynamic radiosteriometric analysis (RSA) using high-speed biplanar fluoroscopy with the dogs walking on a treadmill. dRUI, in the form of proximo-distal translation of the radius relative to the ulna, was measured for the first third of stance phase and compared between groups using unpaired t-testing. Healthy elbow joints exhibited a relative radio-ulnar translation of 0.7 mm (SD 0.31 mm), while dysplastic joints showed a translation of 0.5 mm (SD 0.30 mm). No significant difference between groups was detected (p = 0.2092, confidence interval -0.6 – 0.2). Based on these findings dRUI is present in every canine elbow joint, as part of the physiological kinematic pattern. However, dysplastic elbow joints do not show an increased radio-ulnar translation, and therfore dRUI cannot be considered causative for medial coronoid disease.