Stifle Research Articles

Comparison of Digital Radiography, Computed Tomography, and Magnetic Resonance Imaging Features in Canine Spontaneous Degenerative Stifle Joint Osteoarthritis

Canine stifle joint osteoarthritis (OA) is characterized by damage and degeneration of the articular cartilage and subchondral bone, bony hypertrophy at the margins, and synovial joint membrane changes. Non-invasive imaging modalities, such as digital radiography (DR), computed tomography (CT), and magnetic resonance imaging (MRI), can be used to describe these changes. However, the value of MRI in diagnosing spontaneous canine OA and the comparison of different imaging modalities have seldom been addressed. This study compared multiple noninvasive imaging modalities in canine spontaneous stifle OA cases. Four client-owned dogs with five spontaneously affected OA stifle joints were recruited and underwent DR, CT, and MRI. Information on osteophytes/enthesophytes, ligament/tendon lesions, synovial effusion and membrane thickening, subchondral bone lesions, and meniscal and cartilage lesions were scored and compared. The results showed that MRI provides the most comprehensive and superior lesion detection sensitivity for ligament, meniscus, cartilage, and synovial effusions. DR provides adequate bony structure information, while CT provides the most delicate images of bony structure lesions. These imaging findings may provide further understanding of the disease and help clinicians draft a more precise treatment plan.

Histological Findings and T2 Relaxation Time in Canine Menisci of Elderly Dogs—An Ex Vivo Study in Stifle Joints

Osteoarthritis is a chronic disease that often affects the canine stifle joint. Due to their biomechanical function, the menisci in the canine stifle play an important role in osteoarthritis. They compensate for the incongruence in the joint and distribute and minimize compressive loads, protecting the hyaline articular cartilage from damage. Meniscal degeneration favors the development and progression of stifle joint osteoarthritis. Qualitative magnetic resonance imaging (MRI) is the current golden standard for detecting meniscal changes, but it has limitations in detecting early signs of meniscal degeneration. A quantitative MRI offers new options for detecting early structural changes. T2 mapping can especially visualize structural changes such as altered collagen structures and water content, as well as deviations in proteoglycan content. This study evaluated T2 mapping and performed a histological scoring of menisci in elderly dogs that had no or only low radiographic osteoarthritis grades. A total of 16 stifles from 8 older dogs of different sex and breed underwent ex vivo magnet resonance imaging, including a T2 mapping pulse sequence with multiple echoes. A histological analysis of corresponding menisci was performed using a modified scoring system. The mean T2 relaxation time was 18.2 ms and the mean histological score was 4.25. Descriptive statistics did not reveal a correlation between T2 relaxation time and histological score. Ex vivo T2 mapping of canine menisci did not demonstrate histological changes, suggesting that early meniscal degeneration can be present in the absence of radiological signs of osteoarthritis, including no significant changes in T2 relaxation time.

Proteomics identifies novel biomarkers of synovial joint disease in a canine model of mucopolysaccharidosis I.

Mucopolysaccharidosis I is a lysosomal storage disorder characterized by deficient alpha-L-iduronidase activity, leading to abnormal accumulation of glycosaminoglycans in cells and tissues. Synovial joint disease is prevalent and significantly reduces patient quality of life. There is a critical need for improved understanding of joint disease pathophysiology in MPS I, including specific biomarkers to predict and monitor joint disease progression, and response to treatment. The objective of this study was to leverage the naturally-occurring MPS I canine model and undertake an unbiased proteomic screen to identify systemic biomarkers predictive of local joint disease in MPS I. Synovial fluid and serum samples were collected from MPS I and healthy dogs at 12 months-of-age, and protein abundance characterized using liquid chromatography tandem mass spectrometry. Stifle joints were evaluated postmortem using magnetic resonance imaging (MRI) and histology. Proteomics identified 40 proteins for which abundance was significantly correlated between serum and synovial fluid, including markers of inflammatory joint disease and lysosomal dysfunction. Elevated expression of three biomarker candidates, matrix metalloproteinase 19, inter-alpha-trypsin inhibitor heavy-chain 3 and alpha-1-microglobulin, was confirmed in MPS I cartilage, and serum abundance of these molecules was found to correlate with MRI and histological degenerative grades. The candidate biomarkers identified have the potential to improve patient care by facilitating minimally-invasive, specific assessment of joint disease progression and response to therapeutic intervention.

A practical approach to localization of a suppurative cavity and resolution of a chronic draining tract in a horse

AbstractThis case report describes a practical method for resolving a hard to localize abscess in a horse resulting from a traumatic injury near the stifle joint. When the horse presented for a chronic draining tract, a foreign body was suspected, with no external indication of location. Although ultrasonography was attempted to localize the abscess, the practitioner could not confidently identify the source of the draining tract. Radiography revealed a gas‐filled cavity approximately 28 cm proximal to the tract opening. In order to establish continuity between the tract opening and the presumed suppurative cavity, the practitioner developed a malleable radiopaque probe from readily available materials. Ultrasonography combined with the radiopaque probe allowed for confident localization and formulation of a surgical plan. The use of inexpensive available materials minimized cost and avoided delays in diagnosis and treatment. This improvised fistulographic method is suitable for practitioners at any skill level or practice setting.

Integrating MR imaging with full-surface indentation mapping of femoral cartilage in an ex vivo porcine stifle

The potential of MRI to predict cartilage mechanical properties across an entire cartilage surface in an ex vivo model would enable novel perspectives in modeling cartilage tolerance and predicting disease progression. The purpose of this study was to integrate MR imaging with full-surface indentation mapping to determine the relationship between femoral cartilage thickness and T2 relaxation change following loading, and cartilage mechanical properties in an ex vivo porcine stifle model. Matched-pairs of stifle joints from the same pig were randomized into either 1) an imaging protocol where stifles were imaged at baseline and after 35 min of static axial loading; and 2) full surface mapping of the instantaneous modulus (IM) and an electromechanical property named quantitative parameter (QP). The femur and femoral cartilage were segmented from baseline and post-intervention scans, then meshes were generated. Coordinate locations of the indentation mapping points were rigidly registered to the femur. Multiple linear regressions were performed at each voxel testing the relationship between cartilage outcomes (thickness change, T2 change) and mechanical properties (IM, QP) after accounting for covariates. Statistical Parametric Mapping was used to determine significance of clusters. No significant clusters were identified; however, this integrative method shows promise for future work in ex vivo modeling by identifying spatial relationships among variables.

Etiopathogenesis of Canine Cruciate Ligament Disease: A Scoping Review.

The spontaneous rupture of the cranial cruciate ligament in dogs remains a pathoetiologic puzzle. Despite much progress in research over the past years, the systemic and local mechanisms leading to ligament degeneration and structural failure remain largely obscure. This scoping review focuses on pathogenesis and aims at summarizing and interpreting today's knowledge on causes of canine cruciate ligament rupture, i.e., the multifactorial mechanisms leading to degenerative stifle joint disease with collagen matrix degeneration and structural failures. Thus, the initial view of traumatic ligament rupture, fostered by "wear and tear", has clearly been replaced by a new concept of systemic processes linked to progressive degenerative joint disease and ligament failure; thus, the term "cranial cruciate ligament disease" has been coined and is generally accepted. In addition, cruciate ligament rupture in people shares some similarities with the lesion in dogs; therefore, the review also includes comparative studies. The methods used were based on the PRISMA-ScR model (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews).

Quantification of equine stifle passive kinematics

This study aims to quantitatively characterize the passive kinematics of the healthy, soft tissue-intact equine stifle to establish an objective foundation for providing insights into the etiology of stifle disorders and developing a possible surgical treatment for stifle degenerative disease. 5 whole-horse specimens. Reflective markers with intracortical bone pins and a motion capture system were used to investigate the stifle joint kinematics. Kinematics of 5 whole-horse specimens euthanized within 2 hours were calculated for internal/external rotation, adduction/abduction, and cranial/caudal translation of the medial and lateral femoral condyles and estimated joint contact centroids as functions of joint extension angle. From 41.7° to 121.6° (mean ± SD, range of motion: 107.5° ± 7.2°) of joint extension, 13° ± 3.7° of tibial external rotation and 6° ± 2.7° of adduction were observed. The lateral femoral condyle demonstrated significantly greater cranial translation than the medial during extension (23.7 mm ± 9.3 mm vs. 14.3 mm ± 7.0 mm, P = .01). No significant difference was found between the cranial/caudal translation of estimated joint contact centroids in the medial and lateral compartment (13.3 mm ± 7.7 mm vs. 16.4 mm ± 5.8 mm, P = .16). The findings share similarities with kinematics for human knees and sheep and dog stifles, suggesting it may be possible to translate what has been learned in human arthroplasty to treatment for equine stifles.

Postoperative efficacy of chondroprotectors and diacerein in dogs with osteoarthritis secondary to cranial cruciate ligament disease.

Cranial cruciate ligament disease is one of the leading causes of pelvic limb claudication in canines and osteoarthritis in the stifle joint. Historically, studies have focused on surgical options to improve the stability of the stifle joint, although none of the techniques described in the literature prevents the development of osteoarthritis. This study aimed at proving the presence of osteoarthritis at the time of diagnosis of cranial cruciate ligament rupture, as well as evaluating the benefits of administering diacerein (DAR) or chondroprotective coadjuvants to the extracapsular fabelo-tibial technique. Seventeen dogs aged between 2 and 8, weighing more than 25 kg, with no predilection for breed or sex, were operated on using this technique. These were divided into three groups: DAR, Chondroprotector (CP), and Control. The animals were treated for 90 days and controlled clinically, radiologically, and using multidimensional scales for pain and quality of life. The statistical analysis used was descriptive and through non-parametric tests. All patients had some degree of osteoarthritis at the beginning of the study associated with the presence of pain. The treated groups improved the claudication scores; however, the changes were significant for the DAR group. The pain score improved in all animals, including those in the Control group; however, the differences were significant only in the treated groups. On the other hand, no significant differences were detected in the radiological studies, so it would be convenient to perform this study over more than 90 days. The surgical treatment accompanied by drugs that act on the degradation of articular cartilage has better clinical results.

Evaluation of proximodistal patellar alignment in small breed dogs with or without patellar luxation using the Insall-Salvati, Caton-Deschamps, and Blackburne-Peel indices.

Patellar luxation in dogs is thought to be related to proximally (patella alta) or distally (patella baja) positioned patella in the femoral trochlea. The aim of the present study was to calculate and compare the values of Insall-Salvati (ISI), Caton-Deschamps (CDI), and Blackburne-Peel indices (BPI) in orthopedically healthy dogs and dogs with various grades of medial patellar luxation (MPL) from small breeds on mediolateral radiographs. The study included 87 dogs (138 stifles) from four breeds (Mini-Pinschers, Pomeranians, Chihuahuas, and Yorkshire terriers). Seventy joints (53 dogs) were diagnosed with various grades of MPL and another 68 joints from 34 dogs, free of orthopedic or neurological disorders, were used as controls. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic value of the three indices. The CDI and BPI showed no significant difference between healthy and MPL joints. The ROC analysis showed that all three studied indices of proximodistal patellar position had poor diagnostic values with low sensitivity and specificity of respective cutoff values. In dogs from the studied four small breeds, the proximodistal ISI, CDI, and BPI patellar indices could not discriminate reliably between healthy stifle joints and joints with MPL.

脛骨高平部水平化骨切り術実施後の脛骨前方引き出し兆候に関する検討

Although it is considered that tibial cranial drawer signs (TCDS) do not disappear with tibial plateau leveling osteotomy (TPLO), in some cases, this may occur and is presumed to be due to periarticular fibrosis; however to our knowledge, no reports have confirmed the disappearance of TCDS after TPLO. Here, we aimed to identify factors influencing the presence/absence of TCDS after TPLO. Thirty-five canine stifle joints requiring TPLO for cranial cruciate ligament rupture were assessed preoperatively, immediately postoperatively, and each month for 3 months following surgery. The cases were classified as those in which TCDS disappeared (13 stifles, disappeared group) and those in which TCDS remained (22 stifles, residual group). The osteoarthritis (OA) score at each postoperative time point was subtracted from the preoperative OA score (variation in OA score). There were no differences between the two groups, except in the preoperative OA scores (which were higher in the disappeared group). Significant increases in the variations in OA score were observed over time in both groups; these variations were significantly higher in the disappeared than in the residual group at 1, 2, and 3 months postoperatively. Disappearance of TCDS after TPLO is associated with a higher degree of OA progression, suggesting involvement of OA progression factors and periarticular fibrosis.

Patellar Proximo-Distal Displacement following Modified Maquet Technique Is Not Predictive of Patellar Luxation.

The aim of this study was to test the low sensitivity of the Allberg and Miles index to the stifle opening angle, evaluate the displacement of the patella after a Modified Maquet Technique using this index and assess the incidence of patellar luxation post-Modified Maquet Technique in dogs. Medical records were reviewed from 2012 to 2017. Allberg Miles index were determined for each stifle pre- and postoperatively, as well as the stifle joint opening of each case. Occurrence of patellar luxation was recorded. 137 stifles on 116 dogs were reviewed. The stifle opening angle did not influence the Allberg Miles index. Pre- and postoperative index showed a distal displacement of the patella after a Modified Maquet Procedure, especially at 135° of stifle opening angle. Only 1/137 cases demonstrated patellar luxation after the surgery. Based on our statistical analysis, we were able to conclude that within the maximum stifle opening angle range recorded in our series of cases; the Allberg Miles index variation was not significant. While patellar baja is clearly induced by the Modified Maquet Technique, the latter did not seem to predispose patients to post-operative patellar luxation in our study population.

Stifle joint osteoarthritis in small-breed and medium-breed dogs is more severe after cranial cruciate ligament injury than medial patellar luxation.

This retrospective observational study aimed to characterize the severity and distribution of OA in the stifle joints of small and medium dogs with CCL injury and/or MPL. Radiographs of the stifle joints from 218 dogs from 10 small and medium breeds were included; 127 joints had CCL injury, 76 joints had MPL, and 73 joints had CCL injury and MPL. OA was graded at 33 sites within the joint. The mean± SD OA score was 20.3± 9.9. For all joints, OA was more severe in heavier than lighter dogs (P = 0.003). Joints with MPL (14.9± 8.2) had lower OA scores than joints with CCL injury (22.2± 10.0, P = 0.003) or CCL injury and MPL (22.6± 9.4, P < 0.001). OA scores were higher in joints with MPL for older dogs (r = 0.408, P < 0.001) but did not change with age in joints with CCL injury. The pattern of OA did not differ among joints with CCL injury or MPL. The retrospective nature of the study limited findings to associations but did not allow conclusions regarding factors causing OA or enhancing its progression. We concluded that, in small- and medium-breed dogs, the patterns of stifle OA joint after CCL injury and MPL are similar. Radiographic OA after CCL injury is more severe than MPL. An increase in age leads to an increase in OA at the time of presentation at a referral hospital in stifle joints with MPL and without CCL injury.

Degree of osteophyte formation seen on radiographs provides useful prognostic information for dogs with cruciate ligament disease.

Concurrent osteoarthritis is generally present in the stifle joints of dogs with cranial cruciate ligament disease (CCLD), but it is not known if the degree of osteoarthritis-related changes affects the prognosis. Development of osteophytes is a key radiographic feature of osteoarthritis. The aim of this study was to evaluate the association between the degree of osteophyte formation seen on radiographs and CCLD-related euthanasia in dogs with CCLD. A retrospective cohort study including 226 dogs treated for CCLD at two university animal hospitals was performed. Clinical and follow-up information was retrieved, and stifle radiographs taken during the 31 days before treatment for the CCLD were graded for osteophyte formation by three veterinary radiologists. A multivariable Cox proportional hazards model was applied to assess the association between the degree of osteophyte formation and CCLD-related euthanasia. An association between the degree of osteophyte formation and CCLD-related euthanasia was found, with increased osteophyte formation associated with an increased hazard of CCLD-related euthanasia (hazard ratio 1.06, 95% confidence interval 1.01-1.11, p = 0.01). No clinical assessment of the outcome was performed. The findings suggest that evaluation of stifle radiographs for osteophyte formation could provide useful prognostic information for dogs with CCLD.

Impacts of tibial plateau levelling osteotomy on the tibial insertion of the medial collateral ligament of the canine stifle joint – A cadaveric study

ObjectiveThe aim of this study was to assess the potential consequences of tibial plateau levelling osteotomy (TPLO) for the medial collateral ligament (MCL) tibial insertion (TI) with a particular focus on the effects of the TPLO planning technique and of the size of saw blade. Study designEighty-six stifle joints were collected from 43 canine cadavers and dissected free of soft tissue to expose the MCL. The MCL insertion sites were first identified with Chinese ink on intact stifle joints, and then marked with radio-opaque barium sulfate after removal of the MCL. Mediolateral radiographs were made of each marked stifle joint and used for TPLO digital planning. For each stifle, planning the TPLO was performed by centring the osteotomy at the intersection of the tibial plateau and the mechanical axis of the tibia in group 1, and at the top of the intercondylar tubercles in group 2. Whenever possible, two saw blade sizes were tested in each group. Measurements were taken after TPLO simulation to assess how the procedure would alter the MCL TI. ResultsIn group 1, the integrity of the MCL TI was affected by the TPLO planning in 87.2% of the cases with the small saw blade and in 59.3% of the cases with the large blade, and in group 2, in 94.2% of the cases with the small and 77.9% with the large saw blade. In group 1, the osteotomy line was located above the TI, completely severing the MCL in four cases versus in 11 cases in group 2, while severing occurred in 14/15 cases with the small saw blade. ConclusionDuring TPLO, the osteotomy line transected the MCL TI in the majority of dogs. Centring the osteotomy at the intersection of the tibial plateau and the mechanical axis of the tibia and using the largest saw size that preserves tibial tuberosity and patellar tendon insertion seems to be the best way to preserve the MCL TI as much as possible. Further research is needed to evaluate the clinical impact of MCL TI transection.

Histopathological study of the effect of using repeated doses of platelets-rich plasma on articular cartilage repair in Rabbits

The present study was performed on platelet-rich plasma compound from animals engaged in this work, to be directly injected in the joint space of the affected stifle joint 5mm diameter full-thickness articular cartilage removal in the knee joint manually using the same instrument 5 mm drill to remove the cartilage, by different doses to evaluate its influence on articular cartilage repair. In this experiment, 28 adult rabbits were used. The same defect is created on the lateral condyle of the distal end of the femur. Three identical groups of animals were formed randomly. Group I was untreated. Group II was treated with a single dose of PRP (which was administered immediately after the creation of the defect), and group III was treated with two doses of PRP (the first dose was given immediately after the creation of the defect, and the second doses after 15 days of the first one. The histological examinations were recorded of four rabbits of each group, which were euthanized one and two months after treatment, and the assessment of cartilage tissue repair was checked. The control group showed destruction of articular cartilage at the site of the lesion with involvement of subchondral bone in both periods 30 and 60 days of examination, while specimens taken from groups II and III after 30 days showed a new tissue formation which is characterized as the homogenous extracellular matrix, with the proliferation of active chondrocytes. At the same time, slides on day 60 of treatment showed an increased number of newly formed chondrocytes and a clear line of demarcation between articular cartilage and subchondral bone, representing the tissue filling the gap had been created at the beginning of the experiment.

Vergleichende Langzeitergebnisse zwischen Tibial Plateau Leveling Osteotomy und Modified Maquet Procedure nach Ruptur des vorderen Kreuzbandes beim Hund

This study aims to compare the Modified Maquet Procedure (MMP) with the Tibial Plateau Leveling Osteotomy (TPLO) using long-term follow-up examinations over the period of more than one year (∅ 3,15 years) by clinical examination, radiographic assessment of osteoarthritis progression, and gait analysis by treadmill examination. Additional aim is to review the influence of surgeons' experience in TPLO technique. This clinical study included 67 stifle joints of 50 dogs of different breeds between 20 and 40 kilograms body weight that were treated by TPLO (n = 48) or MMP (n = 19) following the rupture of the cranial cruciate ligament. The TPLO group was further divided into a group operated by two experienced surgeons (TPLO1, n = 25) and a second group operated by several surgeons with different experience (TPLO2, n = 23). Following a post-operative time period of more than one year in the least (mean, 3.15 ± 1.21 years) orthopedic and radiographic examinations as well as separate unilateral and bilateral gait analyses were conducted. In addition, gait analysis data were compared with an orthopedically healthy control group. No significant and clinically relevant differences were observed between the 3 groups in the results of their orthopedic examination.Osteoarthritis progression showed similar values in all 3 surgical groups. On average per year this feature was slightly but statistically significantly lower in the TPLO2 group in comparison to the TPLO1 and MMP groups.Gait analysis during walking exhibited significant differences in bilateral ruptures at the Peak Vertical Force and the Vertical Impulse, especially when compared to the healthy control group. Stance phase duration did not show any significant differences. At trot, no significant differences were found between the 3 surgical groups. Both surgical techniques achieved good clinical, radiological, and gait analysis results in the 3 groups at long-term follow-up, even when compared with a healthy control group. MMP can be considered a rapid feasible alternative to the established TPLO method also bearing satisfactory results in dogs. The degree of the surgeon's experience does not seem to influence the outcome.

Deep learning-based diagnosis of stifle joint diseases in dogs.

In this retrospective, analytical study, we developed a deep learning-based diagnostic model that can be applied to canine stifle joint diseases and compared its accuracy with that achieved by veterinarians to verify its potential as a reliable diagnostic method. A total of 2382 radiographs of the canine stifle joint from cooperative animal hospitals were included in a dataset. Stifle joint regions were extracted from the original images using the faster region-based convolutional neural network (R-CNN) model, and the object detection accuracy was evaluated. Four radiographic findings: patellar deviation, drawer sign, osteophyte formation, and joint effusion, were observed in the stifle joint and used to train a residual network (ResNet) classification model. Implant and growth plate groups were analyzed to compare the classification accuracy against the total dataset. All deep learning-based classification models achieved target accuracies exceeding 80%, which is comparable to or slightly less than those achieved by veterinarians. However, in the case of drawer signs, further research is necessary to improve the low sensitivity of the model. When the implant group was excluded, the classification accuracy significantly improved, indicating that the implant acted as a distraction. These results indicate that deep learning-based diagnoses can be expected to become useful diagnostic models in veterinary medicine.

Osteochondral Explant Isolation and Culture Under a Compression and Shear Bioreactor.

Osteochondral explants harvested from different species are valuable preclinical ex vivo models for tissue engineering research. In this chapter, we describe the isolation of osteochondral plugs from bovine stifle joints, followed by defect creation, and plug preparation in a straightforward manner before mechanical loading using a compression and shear bioreactor. The method can be adapted to isolate osteochondral plugs from any animal species and to load explants in any type of bioreactor.

Previous Exercise on a Water Treadmill at Different Depths Affects the Accelerometric Pattern Recorded on a Track in Horses.

During a water treadmill (WT) exercise, horses change their accelerometric patterns. We aimed to analyze if these changes persist during terrestrial locomotion. Six horses were randomly subjected to 40 min duration WT exercises, without water (WW), at the depth of fetlock (FET), carpus (CAR) and stifle (STF), with a day off between them. Before and after 30 min after WT, horses were evaluated at walk and at trot on a track with a triaxial accelerometer fixed on the pectoral (PECT) and sacrum (SML) regions. The percent of change from baseline (before WT and after each exercise session) were calculated. Total, dorsoventral, longitudinal and mediolateral accelerometric activities and dorsoventral displacement increased with the accelerometer in PECT but decreased after WT at STF. Velocity increased with the accelerometer in PECT but decreased with the accelerometer in SML, particularly after WT at STF. A reduction in stride frequency was found with the accelerometer in PECT. SL increased with the accelerometer in SML but decreased with WT at STF. Some accelerometric changes that happened on WT remained shortly in terrestrial locomotion. The reduction in some parameters after WT at STF depth seems to indicate fatigue. This should be considered in training or rehabilitation programs for unfit animals.

A pilot study of microRNA assessment as a means to identify novel biomarkers of spontaneous osteoarthritis in dogs

MicroRNAs (miRNAs) are important regulators of intercellular signaling and are promising biomarkers in osteoarthritis (OA). In this study, comprehensive analysis was performed to identify miRNAs involved in the pathogenesis of spontaneous OA in dogs. Dogs diagnosed with OA based on radiography and arthroscopy of the stifle joint were included in the OA group. Dogs without any evidence of orthopedic disease were included in the unaffected group. To investigate miRNA expression levels, RNA sequencing analysis (RNA-seq) was performed in synovial tissue (OA group: n = 3, Unaffected group: n = 3) and RT-qPCR was performed in synovial tissue, synovial fluid and serum (OA group: n = 17, Unaffected group: n = 6), and compared between the two groups. The RNA-seq results showed that 57 miRNAs were significantly upregulated and 42 were significantly downregulated in the OA group. Specifically, miR-542 and miR-543 expression levels in the synovial tissue, synovial fluid, and serum were consistently higher in the OA group than in the unaffected group, suggesting that these miRNAs may be used as biomarkers for detecting canine OA. This is the first report to comprehensively analyze the expression patterns of miRNAs in the synovial tissue of dogs with spontaneous OA.