Functional outcome measures in a surgical model of hip osteoarthritis in dogs

The surgical destabilization of the abductor muscle leads to development of instability-associated hip osteoarthritis in mice

Osteoarthritis (OA) of the hip is a common and debilitating painful joint disease. However, there is paucity of surgically induced hip OA models in small animals that allow scientists to study the onset and progression of the disease. A growing body of evidence indicates a positive association between periarticular myotendinous pathology and the development of hip OA. Thus, in the current study, we aimed to establish a novel mouse instability-associated hip OA model via selective injury of the abductor complex around the hip joint. C57BL6/J mice were randomized to sham surgery or abductor injury, in which the myotendinous insertion at the third trochanter and greater trochanter were surgically detached. Mice were allowed free active movement until they were sacrificed at either 3 weeks or 20 weeks post-injury. Histologic analyses and immunohistochemical staining of the femoral head articular cartilage were performed, along with microCT (µCT) analysis to assess subchondral bone remodeling. We observed that mice receiving abductor injury exhibited significantly increased instability-associated OA severity with loss of proteoglycan and type II collagen staining compared to sham control mice at 20 weeks post-surgery, while comparable matrix metalloproteinase 13 expression was observed between injury and sham groups. No significant differences in subchondral bone remodeling were found after 3 or 20 weeks following injury. Our study further supports the link between abductor dysfunction and the development of instability-associated hip OA. Importantly, this novel surgically induced hip OA mouse model may provide a valuable tool for future investigations into the pathogenesis and treatment of hip OA.

Enhanced Classification of Dog Activities with Quaternion-Based Fusion Approach on High-Dimensional Raw Data from Wearable Sensors

The employment of machine learning algorithms to the data provided by wearable movement sensors is one of the most common methods to detect pets' behaviors and monitor their well-being. However, defining features that lead to highly accurate behavior classification is quite challenging. To address this problem, in this study we aim to classify six main dog activities (standing, walking, running, sitting, lying down, and resting) using high-dimensional sensor raw data. Data were received from the accelerometer and gyroscope sensors that are designed to be attached to the dog's smart costume. Once data are received, the module computes a quaternion value for each data point that provides handful features for classification. Next, to perform the classification, we used several supervised machine learning algorithms, such as the Gaussian naïve Bayes (GNB), Decision Tree (DT), K-nearest neighbor (KNN), and support vector machine (SVM). In order to evaluate the performance, we finally compared the proposed approach's F-score accuracies with the accuracy of classic approach performance, where sensors' data are collected without computing the quaternion value and directly utilized by the model. Overall, 18 dogs equipped with harnesses participated in the experiment. The results of the experiment show a significantly enhanced classification with the proposed approach. Among all the classifiers, the GNB classification model achieved the highest accuracy for dog behavior. The behaviors are classified with F-score accuracies of 0.94, 0.86, 0.94, 0.89, 0.95, and 1, respectively. Moreover, it has been observed that the GNB classifier achieved 93% accuracy on average with the dataset consisting of quaternion values. In contrast, it was only 88% when the model used the dataset from sensors' data.

Pilot comparison of outcome measures across chemical and surgical experimental models of chronic osteoarthritis in the rat (Rattus norvegicus)

Relatively little work has evaluated both the disease of osteoarthritis (OA) and clinically-relevant pain outcome measures across different OA models in rats. The objective of this study was to compare sensitivity, pain, and histological disease severity across chemical and surgical models of OA in the rat. Stifle OA was induced in Sprague-Dawley rats via intraarticular injection of monoiodoacetate (MIA) or surgical transection of anterior cruciate ligament and/or destabilization of medial meniscus (ACL+DMM or DMM alone). Reflexive (e.g., mechanical and thermal stimuli) measures of sensitivity and non-reflexive assays (e.g., lameness, static hindlimb weight-bearing asymmetry, dynamic gait analysis) of pain were measured over time. Joint degeneration was assessed histologically. Six-weeks post OA-induction, the ACL+DMM animals had significantly greater visually observed lameness than MIA animals; however, both ACL+DMM and MIA animals showed equal pain as measured by limb use during ambulation and standing. The MIA animals showed increased thermal, but not mechanical, sensitivity compared to ACL+DMM animals. Joint degeneration was significantly more severe in the MIA model at 6 weeks. Our pilot data suggest both the ACL+DMM and MIA models are equal in terms of clinically relevant pain behaviors, but the MIA model is associated with more severe histological changes over time potentially making it more suitable for screening disease modifying agents. Future work should further characterize each model in terms of complex pain behaviors and biochemical, molecular, and imaging analysis of the sensory system and joint tissues, which will allow for more informed decisions associated with model selection and investigative outcomes.

Appendicular skeletal muscle mass assessment in dogs: a scoping literature review

BACKGROUND

Monitoring changes in appendicular skeletal muscle mass is frequently used as a surrogate marker for limb function. The primary objective of this study was to review scientific information related to the assessment of appendicular skeletal muscle mass in dogs. The secondary objective was to develop practical recommendations for serial evaluation of muscle mass.

METHODS

A scoping review was conducted with a systematic search of PubMed, Web of Science, CAB abstract, and Cochrane from inception to June 2021. The following modalities were included in the search: limb circumference, diagnostic ultrasound, computed tomography, magnetic resonance imaging, and dual-energy x-ray absorptiometry.

RESULTS

A total of 62 articles that measured appendicular skeletal muscle mass in dogs were identified. Limb circumference (55 articles) was the most commonly used modality. Its reliability was investigated in five studies. Several factors, including measuring tape type, body position, joint angles, and the presence of hair coat, were reported as variables that can affect measurements. Diagnostic ultrasound (five articles) was validated in three articles, but there is scarce information about observer reliability and variables affecting the measurement. Computed tomography (four articles) and magnetic resonance imaging (one article) have been used to validate other modalities at a single time point rather than as a clinical tool for serial muscle mass monitoring. Dual-energy x-ray absorptiometry (two articles) has been used to quantify specific skeletal muscle mass but was mainly used to evaluate body composition in dogs.

CONCLUSION

Limb circumference and ultrasound are likely the main modalities that will continue to be used for serial muscle mass measurement in the clinical setting unless a new technology is developed. The reliability of limb circumference is questionable. Several key factors, including measuring tape type, body position, joint angles, and coat clipping, need to be controlled to improve the reliability of limb circumference measurements. Ultrasound may provide a reasonable alternative, but further studies are required to evaluate the reliability of this modality and identify factors that influence ultrasound measurements.

Changes in Ground Reaction Forces and Center of Pressure Parameters of Paws When Wearing Dog Boots in Dogs

Dog boots are commonly used as protective footwear against snow, ice, hot sand, road salt, and paw injury. Only a few studies exist in veterinary medicine that capture the impact of dog boot replacements, such as bandages, on ground reaction forces (GRF) in dogs. To our knowledge, no studies have investigated the effect of dog boots on the center of pressure (COP) in dogs. This study investigated changes in the GRF of the whole limb and selected COP parameters of the paws while wearing dog boots in five Labrador Retrievers. After habituation, data were collected by walking and trotting dogs over a pressure platform without boots (control measurement) and under five different test conditions (wearing boots on all limbs, boots on both front limbs, boots on both hind limbs, one boot on the left front limb, and one boot on the right hind limb). The most prominent change was detectable when one boot was worn on the left front limb, with a decrease of peak vertical force (PFz%) in the left front limb at trot which led to a significant difference between both front limbs and a significant increase of PFz (%) in the right hind limb. Additionally, in both tempi, the vertical impulse (IFz%) showed significant differences between the front limbs; in trot, there was also an increase in the right front limb compared with the control. Furthermore, some significant changes in COP parameters were detected; for instance, all test conditions showed a significant increase in COP area (%) at the right front limb during walking compared to the control. Therefore, our results show that wearing the tested dog boots in different constellations seems to have an impact on GRF and some COP parameters.

Biological resurfacing in a canine model of hip osteoarthritis

Articular cartilage has unique load-bearing properties but has minimal capacity for intrinsic repair. Here, we used three-dimensional weaving, additive manufacturing, and autologous mesenchymal stem cells to create a tissue-engineered, bicomponent implant to restore hip function in a canine hip osteoarthritis model. This resorbable implant was specifically designed to function mechanically from the time of repair and to biologically integrate with native tissues for long-term restoration. A massive osteochondral lesion was created in the hip of skeletally mature hounds and repaired with the implant or left empty (control). Longitudinal outcome measures over 6 months demonstrated that the implant dogs returned to normal preoperative values of pain and function. Anatomical structure and functional biomechanical properties were also restored in the implanted dogs. Control animals never returned to normal and exhibited structurally deficient repair. This study provides clinically relevant evidence that the bicomponent implant may be a potential therapy for moderate hip osteoarthritis.

Defining the rate of, and factors influencing, radiographic progression of osteoarthritis of the canine hip joint

BACKGROUND

This study aimed to define the rate of progression of radiographic osteoarthritis (OA) of the canine hip joint and to describe factors affecting this progression.

METHODS

Dogs that underwent unilateral total hip replacement (THR) were reviewed for the evaluation of radiographic appearance of the non-operated hip joint over time. Standard extended ventrodorsal hip radiographs were taken preoperatively and postoperatively. All images were anonymized, randomized and scored using three different methods. The mean daily change between evaluations was calculated in each individual dog, and the effect of sex, age, body weight, open/closed status of the proximal femoral physis, preoperative severity of OA, time after surgery and their interactions, were investigated as potential influencing factors.

RESULTS

After reviewing the medical records, 163 dogs (468 images) met the inclusion criteria. Consistent across the three scoring systems, radiographic progression of OA was greater in younger (open physis) and spayed female dogs. A subset of seven patients (4.3%) had a faster progression of OA and was considered outliers. No dog was rated as outlier by all three scoring systems.

CONCLUSION

The rate of progression of radiographically assessed coxofemoral OA varies greatly, but is faster in younger, spayed female dogs. Unusually fast progression occasionally occurs.

Bridge-Enhanced Anterior Cruciate Ligament Repair Leads to Greater Limb Asymmetry and Less Cartilage Damage Than Untreated ACL Transection or ACL Reconstruction in the Porcine Model

BACKGROUND

The extent of posttraumatic osteoarthritis (PTOA) in the porcine anterior cruciate ligament (ACL) transection model is dependent on the surgical treatment selected. In a previous study, animals treated with bridge-enhanced ACL repair using a tissue-engineered implant developed less PTOA than those treated with ACL reconstruction (ACLR). Alterations in gait, including asymmetric weightbearing and shorter stance times, have been noted in clinical studies of subjects with osteoarthritis.

HYPOTHESIS

Animals receiving a surgical treatment that results in less PTOA (ie, bridge-enhanced ACL repair) would exhibit fewer longitudinal postoperative gait asymmetries over a 1-year period when compared with treatments that result in greater PTOA (ie, ACLR and ACL transection).

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty-six Yucatan minipigs underwent ACL transection and were randomized to receive (1) no further treatment, (2) ACLR, or (3) bridge-enhanced ACL repair. Gait analyses were performed preoperatively, and at 4, 12, 26, and 52 weeks postoperatively. Macroscopic cartilage assessments were performed at 52 weeks.

RESULTS

Knees treated with bridge-enhanced ACL repair had less macroscopic damage in the medial tibial plateau than those treated with ACLR or ACL transection (adjusted P = .03 for both comparisons). The knees treated with bridge-enhanced ACL repair had greater asymmetry in hindlimb maximum force and impulse loading at 52 weeks than the knees treated with ACL transection (adjusted P < .05 for both comparisons). Although not significant, there was a trend that knees treated with bridge-enhanced ACL repair had greater asymmetry in hindlimb maximum force and impulse loading (adjusted P < .10 for both comparisons) compared with ACLR.

CONCLUSION

Contrary to our hypothesis, the surgical treatment resulting in less macroscopic cartilage damage (ie, bridge-enhanced ACL repair) exhibited greater asymmetry in load-related gait parameters than the other surgical groups. This finding suggests that increased offloading of the surgical knee may be associated with a slower rate of PTOA development.

CLINICAL RELEVANCE

Less cartilage damage at 52 weeks was found in the surgical group that continued to protect the limb from full body weight during gait. This finding suggests that protection of the knee from maximum stresses may be important in minimizing the development of PTOA in the ACL-injured knee within 1 year.

Administration of mesenchymal stem cells from adipose tissue at the hip joint of dogs with osteoarthritis: A systematic review

This systematic review aimed to determine the effects of intra-articular administration of mesenchymal stem cells from adipose tissue in dogs with hip joint osteoarthritis (OA). Clinical trials were systematically reviewed, using PubMed, EMBASE, Cochrane Library, LILACS, Web of Science, Scopus, Open Grey, Google Scholar, and ProQuest Dissertation and Thesis without publication year restrictions. References were screened and selected based on predefined eligibility criteria by two independent reviewers, according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Clinical outcomes were assessed quantitatively using clinical pain scores, physical examination, imaging examination, questionnaire responses, pain in manipulation, gait analysis, range of joint motion, and adverse effects. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist. Out of 1483 articles, six met the inclusion criteria for qualitative analysis, with two randomized controlled trials and four before-and-after studies. All studies reported significantly better clinical outcomes in the adipose tissue stem cells (ADSC) group with improvements in pain and function and decreased evidence of hip OA. The risk of bias was categorized as high in the before-and-after studies and moderate to high in the randomized studies. The studies were considered heterogeneous owing to clinical results and methodology. Because of this heterogeneity, it was not possible to perform meta-analysis. Assessments of ADSC reports yielded positive clinical effects that showed improvements in pain and function and decreased evidence of hip osteoarthritis. More high-level, larger-cohort dog studies that utilize standardized protocols are needed.

Effect of sedation or general anesthesia on elbow goniometry and thoracic limb circumference measurements in dogs with naturally occurring elbow osteoarthritis

OBJECTIVE

To evaluate the effect of sedation or general anesthesia (GA) on elbow goniometry and thoracic limb circumference (TLC) measurements in dogs with elbow osteoarthritis (OA).

STUDY DESIGN

Prospective study.

ANIMALS

Twenty-four client-owned dogs with radiographically confirmed elbow OA.

METHODS

Elbow goniometry and TLC measurements were made before and after either sedation or GA by using a hand-held goniometer and spring tension measuring tape, respectively. Observers were not allowed to review their pre-sedation or pre-GA measurements at the time of obtaining measurements on dogs under sedation or GA. Mixed analysis of variance models were used to compare elbow goniometry and TLC measurements before and after sedation or GA.

RESULTS

Eleven and thirteen dogs were included in the sedation and GA groups, respectively. Mean elbow flexion decreased by 5° and 3° and mean elbow extension increased by 6° and 2° under sedation and GA, respectively. Total range of motion increased by 11° under sedation and by 5° under GA. Each of these changes was statistically significant (P < .05) except elbow extension under GA (P = .129). Sedation and GA did not influence TLC measurements (P > .05).

CONCLUSION

Sedation or GA led to slight and similar increase in elbow flexion and extension but did not influence TLC measurements in dogs with elbow OA.

CLINICAL SIGNIFICANCE

Sedation or GA can cause slight alterations to goniometric measurements in canine elbows with OA. The protocols used in this study for sedation and GA seem interchangeably acceptable for goniometry and TLC measurements in dogs with elbow OA.

Spontaneous dog osteoarthritis - a One Medicine vision

Osteoarthritis (OA) is a global disease that, despite extensive research, has limited treatment options. Pet dogs share both an environment and lifestyle attributes with their owners, and a growing awareness is developing in the public and among researchers that One Medicine, the mutual co-study of animals and humans, could be beneficial for both humans and dogs. To that end, this Review highlights research opportunities afforded by studying dogs with spontaneous OA, with a view to sharing this active area of veterinary research with new audiences. Similarities and differences between dog and human OA are examined, and the proposition is made that suitably aligned studies of spontaneous OA in dogs and humans, in particular hip and knee OA, could highlight new avenues of discovery. Developing cross-species collaborations will provide a wealth of research material and knowledge that is relevant to human OA and that cannot currently be obtained from rodent models or experimentally induced dog models of OA. Ultimately, this Review aims to raise awareness of spontaneous dog OA and to stimulate discussion regarding its exploration under the One Medicine initiative to improve the health and well-being of both species.

Osteoarthritis occurs spontaneously in pet dogs, which often share environmental and lifestyle risk-factors with their owners. This Review aims to stimulate cooperation between medical and veterinary research under the One Medicine initiative to improve the welfare of dogs and humans.

Dogs have many analogous spontaneous diseases that result in end-stage osteoarthritis (OA).

Inbreeding and the predisposition of certain dog breeds for OA enable easier identification of candidate genetic associations than in outbred humans.

Dog OA subtypes offer a potential stratification rationale for aetiological differences and alignment to analogous human OA phenotypes.

The relatively compressed time course of spontaneous dog OA offers longitudinal research opportunities.

Collaboration with veterinary researchers can provide tissue samples from early-stage OA and opportunities to evaluate new therapeutics in a spontaneous disease model.

Awareness of the limitations and benefits of using clinical veterinary patients in research is important.

Correlation of Artemin and GFRα3 With Osteoarthritis Pain: Early Evidence From Naturally Occurring Osteoarthritis-Associated Chronic Pain in Dogs

Arthritis, including osteoarthritis (OA) and other musculoskeletal-associated pain, is a worldwide problem, however, effective drug options are limited. Several receptors, neurotransmitters, and endogenous mediators have been identified in rodent models, but the relevance of these molecules in disease-associated pain is not always clear. Artemin, a neurotrophic factor, and its receptor, glial-derived neurotrophic factor (GDNF) family receptor alpha-3 (GFRα3), have been identified as involved in pain in rodents. Their role in OA-associated pain is unknown. To explore a possible association, we analyzed tissue from naturally occurring OA in dogs to characterize the correlation with chronic pain. We used behavioral assessment, objective measures of limb use, and molecular tools to identify whether artemin and GFRα3 might be associated with OA pain. Our results using banked tissue from well-phenotyped dogs indicates that artemin/GFRα3 may play an important, and hitherto unrecognized, role in chronic OA-associated pain. Elevated serum levels of artemin from osteoarthritic humans compared to healthy individuals suggest translational relevance. Our data provide compelling evidence that the artemin/GFRα3 signaling pathway may be important in OA pain in both non-humans and humans and may ultimately lead to novel therapeutics.

LncRNA DNM3OS promotes proliferation and inhibits apoptosis through modulating IGF1 expression by sponging MiR-126 in CHON-001 cells

Background

As a degenerative disease, osteoarthritis (OA) greatly affects aged population. The human chondrocyte cell line CHON-001, derived from normal human articular cartilage, has been widely used in vitro in osteoarthritis models. In order to better understand the underlying mechanism of OA pathogenesis, this study was conducted to explore the effects of LncRNA dynamin 3 opposite strand (DNM3OS) on CHON-001 cells.

Methods

The expression levels of and correlation between DNM3OS and miR-126 that derived from OA and non-OA tissues were determined by quantitative real time (qRT)-PCR and Spearman’s correlation analysis. Cell viability, clone, migration, invasion and apoptosis were respectively determined by cell counting kit-8, colony formation, wound healing assay, transwell and flow cytometry. The target genes were predicted by starbase V2 and targetscan 7.2 and confirmed by luciferase reporter assay. The expressions of apoptosis-related factors were detected by Western blot.

Results

The expression of DNM3OS was down-regulated in OA patients. Functional assays demonstrated that ectopic expression of DNM3OS promoted the proliferation and inhibited apoptosis of CHON-001 cells, and that knocking down DNM3OS suppressed cell proliferation and induced apoptosis. Mechanistic investigation revealed that DNM3OS physically bound to the promoter of miR-126 and suppressed miR-126 expression. Decreased expression of DNM3OS was negatively correlated with miR-126 in OA patients. Furthermore, the effects of siDNM3OS on inhibiting cell proliferation and promoting apoptosis were partially reversed by miR-126 inhibitor. Meanwhile, type insulin-like growth factor-1 (IGF1) was identified as a target gene for miR-126 and was negatively associated with the miR-126 expression. Overexpressed IGF1 restored the effects of miR-126 mimic in suppressing cell proliferation and promoting apoptosis.

Conclusion

Our results showed that DNM3OS could affect the CHON-001 cell proliferation and apoptosis by regulating IGF1 by sponging miR-126.

Comparison of activity levels derived from two accelerometers in dogs with osteoarthritis: Implications for clinical trials

Accelerometer measurements are frequently reported as total weekly activity counts (AC). Methods of utilizing activity parameters to allow differentiation of activity intensities (i.e., manually derived cut-points) have been described. While this information may provide valuable data for researchers, only few investigators have utilized these methods. This may, in part, be due to the challenge associated with data processing. Some devices, however, generate activity intensity data automatically. This study was conducted to evaluate a novel accelerometer that allows for remote download of data via Wi-Fi (Heyrex), to compare automatically generated parameters quantifying activity levels to previously established cut-points (Actical) and to describe the variability of accelerometer data in dogs with osteoarthritis. Twelve client-owned dogs with osteoarthritis were fitted with a collar with two accelerometers (Heyrex and Actical). Accelerometer data were recorded for 28 days. Pearson bivariate correlations and coefficient of variation (CV%) were calculated for accelerometer data. There was a strong correlation between the AC reported by Heyrex and Actical devices. Several automatically generated parameters showed strong correlations to previously validated cut-points and displayed lower CV% than weekly AC. The activity intensity derived from the Heyrex was associated with the lowest CV% of all parameters from both accelerometers. Automatically generated activity intensity parameters should be considered as potential outcome measures in clinical trials for dogs with osteoarthritis. This novel technology may allow for convenient acquisition of activity intensity data in companion animals. However, technical difficulties (e.g., lack of Wi-Fi connectivity) may pose challenges when using this novel device.

The differentiating ability of four plasma biomarkers in canine hip dysplasia

BACKGROUND

The accumulation of cartilage breakdown products in body fluids has been extensively investigated to assess the accuracy of molecular biomarkers from a diagnostic, prognostic, and therapeutic perspective. Nevertheless, to the authors' knowledge, there is a lack of information about spontaneous models of hip osteoarthritis and the differentiating ability of collagen, noncollagen, and inflammatory biomarkers.

OBJECTIVES

We aimed to assess the accuracy of four plasma biomarkers that could differentiate between healthy dogs and dogs with hip dysplasia.

METHODS

Twenty-four dogs were used in this institutionally approved study (12 in the mild to severe hip dysplasia group; 12 in the control group). Plasma concentrations of biomarkers were compared. The ability of each marker to differentiate control from diseased dogs was assessed using an independent t-test, logistic regression, and receiving operating characteristics (ROC) analysis.

RESULTS

Three biomarkers were significantly different between the two groups. The collagen marker procollagen type II propeptide (PIICP) was useful in differentiating between control and diseased dogs with the best combination of sensitivity and specificity. The four biomarkers showed high area under the curve (AUC) values.

CONCLUSIONS

The results indicate that plasma biomarkers can be used as a screening tool for canine hip dysplasia. Although the cutoff values and diagnostic ability of the biomarkers used in this study show promising results, the sources of individual variability should be addressed. Future studies with larger groups of dogs are needed to correlate plasma levels in serum and synovial fluid during clinical disease.

The in vitro behaviour of canine osteoblasts derived from different bone types

Background

Our understanding of the biology of osteoblasts is important as they underpin bone remodelling, fracture healing and processes such as osseointegration. Osteoblasts isolated from human humeral samples display distinctive biological activity in vitro, which relates to the samples’ bone types (subchondral (S), trabecular (T), cortical (C)). Our aim was to isolate primary osteoblast cultures from different bone types from the proximal femur of a clinical population of dogs presented for total hip replacement and compare the behaviour of the osteoblasts derived from different bone types, to identify a preferred bone type for isolation.

Results

No differences were found for osteoblast doubling time (median for S = 2.9, T = 3.1 and C = 2.71 days, respectively; p = 0.33), final cell number (median for S = 54,849, T = 49,733, C = 61,390 cells/cm²; p = 0.34) or basal tissue non-specific alkaline phosphatase (TNAP) activity (median for S = 0.02, T = 0.02, C = 0.03 U/min/mg protein; p = 0.81) between bone types after 6 days of culture in basal media. There were no differences in mineralizing TNAP activity (S = 0.02, T = 0.02, C = 0.03 U/min/mg protein, p = 0.84) or in mineralized area (S = 0.05, T = 0.04, C = 0.04%, p = 0.92) among cells from different bone types.

Conclusions

There is no significant difference in mean doubling time, basal or mineralizing TNAP activity or mineralized area in osteoblasts derived from subchondral, cortical, or trabecular bone types from the canine femoral head. However, there appears to be a high level of inter-animal variability in the studied parameters, which was independent of age, body mass, and sex. Trabecular isolate osteoblasts have the least variation of the bone types studied, and therefore should be considered a preferred source for primary osteoblast cultures. The work here provides baselines for canine osteoblast function, which has utility for future comparative studies.

Clinical outcomes after common calcanean tendon rupture repair in dogs with a loop-suture tenorrhaphy technique and autogenous leukoreduced platelet-rich plasma

OBJECTIVE

To report outcomes of dogs with common calcanean tendon (CCT) ruptures treated with a platelet-rich plasma (PRP) enhanced nonabsorbable loop-suture technique.

STUDY DESIGN

Retrospective case series.

ANIMALS

Client-owned dogs (n = 12).

METHODS

Medical records (2015-2017) of dogs with CCT ruptures repaired with a loop-suture tenorrhaphy and autogenous leukoreduced PRP were reviewed for signalment, history, type of injury, treatment, and clinical follow-up. Outcomes were assessed by functional anatomic measurements and Canine Orthopedic Index (COI) scores transformed to percentages, with 100% representing no problems.

RESULTS

Twelve tendons were treated. Two dogs had major complications that were successfully revised. Follow-up was available in 11 of 12 dogs, with a median time of 12 months (range, 4-36), including COI for 11 dogs and anatomic measurements for 6 dogs. Anatomic measurements did not differ between treated and normal contralateral limbs (midthigh muscle mass P > .99, cranial tibial muscle mass P = .37, CCT diameter P = .08, tibiotarsal joint angle P > .99). Owners scored function (COI) as 96.4% (range, 93.3%-97.8%) and quality of life as 94.6% (range, 92%-98.2%).

CONCLUSION

Loop-suture tenorrhaphy with application of autogenous leukoreduced PRP at the repair site resulted in restoration of functional anatomic measurements, high COI, and client satisfaction.

CLINICAL SIGNIFICANCE

Loop-suture tenorrhaphy with local application of autogenous leukoreduced PRP appears to offer an acceptable option to treat CCT injuries in dogs.

Canine hip dysplasia: A natural animal model for human developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) in humans is a common condition that is associated with hip pain, functional limitations, and secondary osteoarthritis (OA). Surgical treatment of DDH has improved in the last decade, allowing excellent outcomes at short- and mid-term follow-up. Still, the etiology, mechanobiology, and pathology underlying this disease are not well understood. A pre-clinical animal model of DDH could help advance the field with a deeper understanding of specific pathways that initiate hip joint degeneration secondary to abnormal biomechanics. An animal model would also facilitate different interventional treatments that could be tested in a rigorous and controlled environment. The dog model exhibits several important characteristics that make it valuable as a pre-clinical animal model for human DDH. Dogs are naturally prone to develop canine hip dysplasia (CHD), which is treated in a similar manner as in humans. Comparable to human DDH, CHD is considered a pre-OA disease; if left untreated it will progress to OA. However, progression to OA is significantly faster in dogs than humans, with progression to OA within 1-2 years of age, associated with their shorter life span compared to humans. Animal studies could potentially reveal the underlying biochemical pathway(s), which can inform refined treatment modalities and provide opportunities for new treatment and prevention targets. Herein, we review the similarities and differences between the two species and outline the argument supporting CHD as an appropriate pre-clinical model of human DDH. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1807-1817, 2018.