Reliability of pressure pain, vibration detection, and tactile detection threshold measurements in lower extremities in subjects with knee osteoarthritis and healthy controls.

OBJECTIVES: Quantitative sensory testing (QST) is a method to assess somatosensory function in osteoarthritis (OA), but reliability data on the performance of different QST modalities on different joint structures are missing. The main aims of our study were to assess intertester and intratester reliability of tactile detection thresholds (TDTs), vibration detection thresholds (VDTs), and pressure pain thresholds (PPTs) on different knee joint structures. METHOD: In total, 32 subjects with knee OA and 32 volunteers with healthy knees participated. TDTs, VDTs, and PPTs were examined on the medial tibial condyle, medial tibiofemoral joint line, and rectus femoris muscle twice on the first visit and once after 1-3 weeks. RESULTS: The intratester and intertester intraclass correlation coefficients (ICCs) of PPT measurements varied from 0.60 to 0.90 on different joint structures, showing good to excellent reliability. Intratester reliability (ICC 0.64-0.76) of VDT measurements was higher than intertester reliability (0.48-0.75). The intertester reliability of TDT measurements was excellent in subjects with knee OA (ICC 0.84-0.86) and good in controls (0.67) on the medial tibial condyle. Intratester reliability of TDT measurements varied greatly. CONCLUSION: PPT testing is a reliable tool for measuring pain thresholds on different joint structures. The VDT measurement is reliable when taken by the same evaluator. The reliability of TDT measurements depends on the site of the measurement.

Magnetic resonance imaging (MRI)-defined cartilage degeneration and joint pain are associated with poor physical function in knee osteoarthritis - the Oulu Knee Osteoarthritis study.

OBJECTIVE: The main aim was to investigate the associations between Magnetic Resonance Imaging (MRI)-defined structural pathologies of the knee and physical function. DESIGN: A cohort study with frequency matching on age and sex with eighty symptomatic subjects with knee pain and suspicion or diagnosis of knee osteoarthritis (OA) and 57 asymptomatic subjects was conducted. The subjects underwent knee MRI, and the severity of structural changes was graded by MRI Osteoarthritis Knee Score (MOAKS) in separate knee locations. WOMAC function subscores were recorded and physical function tests (20-m and 5-min walk, stair ascending and descending, timed up & go and repeated sit-to-stand tests) performed. The association between MRI-defined structural pathologies and physical function tests and WOMAC function subscores were evaluated by linear regression analysis with adjustment for demographic factors, other MRI-features and pain with using effect size (ES) as a measure of the magnitude of an association. RESULTS: Cartilage degeneration showed significant association with poor physical performance in TUG-, stair ascending and descending-, 20-m- and 5-min walk-tests (ESs in the subjects with cartilage degeneration anywhere between 0.134 [95%CI 0.037-0.238] and 0.224 [0.013-0.335]) and with increased WOMAC function subscore (ES in the subjects with cartilage degeneration anywhere 0.088 [0.012-0.103]). Also, lateral meniscus maceration and extrusion were associated with poor performance in stair ascending test (ESs 0.067 [0.008-0.163] and 0.077 [0.012-0.177]). CONCLUSIONS: After adjustments cartilage degeneration was associated with both decreased self-reported physical function and poor performance in the physical function tests. Furthermore, subjects with lateral meniscus maceration and extrusions showed significantly worse performance in stair ascending tests.

Intertester and intratester reliability of a movement control test battery for patients with knee osteoarthritis and controls.

OBJECTIVES: To develop a test battery of movement control (MC) tests and assess its intertester and intratester reliability. METHODS: 29 subjects with knee OA with mean age of 64.7 (SD 8.7) years and 12 controls without either knee pain or previous diagnosis of OA (mean age 36.6 (SD 16.2) years) were included. Two experienced physiotherapists rated the filmed test performance of six MC tests blinded to the patients and to each other on 3-point scale as correct, incorrect or failed. Weighted kappa coefficient (wK) with 95% confidence interval (95%CI) and the percentage of agreement were calculated for each test. RESULTS: One-leg stance, one-leg squat 30 degrees and step down tests showed moderate to excellent inter- and intratester reliability with wK ranging between 0.43-0.85 for intertester and 0.51-0.80 for intratester reliability. The reliability of the 90 degrees squat test, small squat and step up tests was poor (wK ranging between 0.09-0.50). CONCLUSIONS: One-leg stance test, one-leg squat 30 degrees and step down test are reliable in the subjects with knee OA and controls. Further studies are needed to evaluate the discriminative validity of the reliable tests.

Associations between MRI-defined structural pathology and generalized and localized knee pain - the Oulu Knee Osteoarthritis study.

OBJECTIVE: To determine the associations between multi-feature structural pathology assessed using magnetic resonance imaging (MRI) and the presence of knee pain, and to determine the associations between the locations of structural changes and different knee pain patterns. METHOD: Eighty symptomatic subjects with knee pain and suspicion or diagnosis of knee OA and 63 asymptomatic subjects underwent knee MRI. Severity of structural changes was graded by MRI Osteoarthritis Knee Score (MOAKS) in separate knee locations. The associations between cartilage damage, bone marrow lesions (BMLs), osteophytes, Hoffa's synovitis, effusion-synovitis, meniscal damage and structural pathologies in ligaments, tendons and bursas and both the presence of pain and the knee pain patterns were assessed. RESULTS: The presence of Hoffa's synovitis (adjusted RR 1.6, 95% CI 1.2-1.3) and osteophytes in any region (2.07, 1.19-3.60) was significantly associated with the presence of pain. Any Hoffa's synovitis was associated with patellar pain (adjusted RR 4.70, 95% CI 1.19-3.60) and moderate-to-severe Hoffa's synovitis with diffuse pain (2.25, 1.13-4.50). Medial knee pain was associated with cartilage loss in the medial tibia (adjusted RR 2.66, 95% CI 1.22-5.80), osteophytes in the medial tibia (2.66, 1.17-6.07) and medial femur (2.55, 1.07-6.09), medial meniscal maceration (2.20, 1.01-4.79) and anterior meniscal extrusions (2.78, 1.14-6.75). CONCLUSIONS: Hoffa's synovitis and osteophytes were strongly associated with the presence of knee pain. Medial pain was associated most often with medially located structural pathologies.

Repeatability of knee impulsive loading measurements with skin-mounted accelerometers and lower limb surface electromyographic recordings during gait in knee osteoarthritic and asymptomatic individuals.

OBJECTIVES: To determine the repeatability of knee joint impulsive loading measurements with skin-mounted accelerometers (SMAs) and lower limb surface electromyography (EMG) recordings during gait. METHODS: Triaxial SMA and EMG from 4 muscles during level and stair walking in nine healthy and nine knee osteoarthritis (OA) subjects were used. The initial peak acceleration (IPA), root mean square (RMS), maximal acceleration transient rate (ATRmax) and mean EMG activity (EMGact) were calculated. The coefficient of variation (CV) and the intraclass correlation coefficient (ICC) were calculated to measure repeatability. RESULTS: The CV and ICC of RMS accelerations ranged from 4.9% to 10.9% and from 0.69 to 0.96 in both study groups during level walking. The CV and ICC of IPA and ATRmax varied from 7.7% to 14.2% and from 0.85 to 0.99 during level and stairs up walking in healthy subjects. The CV and ICC of EMGact ranged from 8.3% to 31.7% and from 0.16 to 0.97 in both study groups. CONCLUSIONS: RMS accelerations exhibited good repeatability during walking in healthy and knee OA subjects. The repeatability of EMG measurements was acceptable in healthy subjects depending on the measured muscles.

Quantification of differences in bone texture from plain radiographs in knees with and without osteoarthritis.

OBJECTIVE: To quantify differences in bone texture between subjects with different stages of knee osteoarthritis (OA) and age- and gender-matched controls from plain radiographs using advanced image analysis methods. DESIGN: Altogether 203 knees were imaged using constant X-ray parameters and graded according to Kellgren-Lawrence (KL) grading scale (KL0: n = 110, KL1: n = 28, KL2: n = 27, KL3: n = 31, KL4: n = 7). Bone density-related and structure-related parameters were calculated from medial and lateral tibial subchondral bone plate and trabecular bone and from femur. Density-related parameters were derived from grayscale values and structure-related parameters from Laplacian- and local binary patterns (LBP)-based images. RESULTS: Reproducibilities of structure-related parameters were better than bone density-related parameters. Bone density-related parameters were significantly (P < 0.05) higher in KL2-4 groups than in control group (KL0) in medial tibial subchondral bone plate and trabecular bone. LBP-based structure parameters differed significantly between KL0 and KL2-4 groups in medial subchondral bone plate, between KL0 and KL1-4 groups in medial and lateral trabecular bone, and between KL0 and KL1-4/KL2-4 in medial and lateral femur. Laplacian-based parameters differed significantly between KL0 and KL2-4 groups in medial side regions-of-interest (ROIs). CONCLUSIONS: Our results indicate that the changes in bone texture in knee OA can be quantitatively evaluated from plain radiographs using advanced image analysis. Based on the results, increased bone density can be directly estimated if the X-ray imaging conditions are constant between patients. However, structural analysis of bone was more reproducible than direct evaluation of grayscale values, and is therefore better suited for quantitative analysis when imaging conditions are variable.

Physical function and properties of quadriceps femoris muscle after bariatric surgery and subsequent weight loss.

OBJECTIVES: To investigate the effects of bariatric surgery-induced weight loss on physical function, the properties of quadriceps femoris muscle (QFM), and the subjective disabilities of the subjects with excessive weight. METHODS: Thirteen female and three male subjects were studied before and 8.8 months after Roux-en-Y gastric bypass (RYGP) operation. The health-related quality of life (RAND-36) and the self-reported disease-specific joint symptoms (WOMAC) were estimated. The objective physical function was evaluated with sock, repeated sit-to-stand, 6-minute walk, stair ascending and descending and timed up and go tests and the properties of the QFM were measured with ultrasound. RESULTS: The average weight loss was 27.3 kg. Objectively measured physical function improved after RYGP operation. Physical functioning, physical role functioning and general health domain scores of the RAND-36 were significantly improved. The stiffness and function scores were lower after RYGP operation in knee OA subjects. The subcutaneous fat thickness and the absolute muscle thickness of QFM decreased, but the ratio of muscle cross sectional area/total body weight did not change. The fat and connective tissue proportion in the QFM muscle were significantly increased. CONCLUSIONS: The RYPG-surgery-induced weight loss exerts a positive impact on physical function but a negative impact on a muscle structure.

Association of 25-hydroxyvitamin D with the incidence of knee and hip osteoarthritis: a 22-year follow-up study.

OBJECTIVE: In the light of conflicting results from previous studies on the role of vitamin D, we studied serum 25-hydroxyvitamin D [25(OH)D] with regard to its prediction of incident knee and hip osteoarthritis (OA). METHODS: The study population (n = 805) consisted of participants of a national health examination survey who had undergone baseline and follow-up clinical examinations at intervals of 20-23 years. Knee and hip OA were diagnosed on the basis of a standardized clinical examination by physicians with the same diagnostic criteria at baseline and follow-up. Information on covariates, including age, sex, season of blood draw, education, body mass index (BMI), physical workload, leisure time physical activity, smoking history, and previous injuries, was collected at baseline. Serum 25(OH)D concentrations were determined from baseline serum samples kept frozen at -20°C. RESULTS: We found no significant association between serum 25(OH)D level and the risk of incident knee or hip OA. However, a statistically significant interaction between season of blood draw and serum 25(OH)D emerged when predicting the development of definite knee OA (p = 0.004). After adjusting for all the covariates, the relative odds (95% confidence interval) of developing definite knee OA per increment of 1 SD (20.7 ng/mL) in winter season 25(OH)D was 1.57 (1.10-2.27), whereas for summer season sera the corresponding rate was 0.53 (0.28-1.00). CONCLUSION: The results do not support the hypothesis that a low level of serum 25(OH)D contributes to the development of OA. Instead, our study suggests that season is a potent effect modifier of 25(OH)D, which merits attention in future research.

The prevalence and consequences of abdominal rectus muscle diastasis among Finnish women: an epidemiological cohort study.

PURPOSE: Post-pregnancy abdominal rectus diastasis (ARD) has raised attention in the field of surgery in recent years, but there is no consensus about when to consider surgery. Our aim was to find out what is the normal inter-rectus distance in fertile aged, female population in Finland and to examine whether there is a linea alba width that would predispose to diastasis-related problems after pregnancy. METHODS: For this prospective cohort study, women participating early pregnancy ultrasound in Helsinki University Hospital Department of Obstetrics and Gynecology during 1.1.2018-8.3.2019, were recruited. The width of linea alba was measured by ultrasound during the early pregnancy ultrasound. Symptoms were measured by questionnaire including Health-Related Quality of Life (RAND-36) and Oswestry Disability Index for back symptoms and disability. RESULTS: Linea alba width was measured in total of 933 women. The average inter-rectus distance (IRD) among nulliparous women was 1.81 ± 0.72 cm. After one previous pregnancy, the average linea alba width was 2.36 cm ± 0.83 cm and after more pregnancies 2.55 ± 1.09 cm. There was a positive correlation between previous pregnancies and the increased linea alba width (p = 0.00004). We did not perceive any threshold value of linea alba width that would predispose to back pain or movement control problems in this cohort, in which severe diastasis (over 5 cm) was rare. CONCLUSION: Mean inter-rectus distance in parous population exceeds stated normative values. Moderate ARD (3.0-5.0 cm) alone does not seem to explain low back pain or functional disability in population level. Severe post-pregnancy diastasis (over 5.0 cm) is rare.

An EMG-Assisted Muscle-Force Driven Finite Element Analysis Pipeline to Investigate Joint- and Tissue-Level Mechanical Responses in Functional Activities: Towards a Rapid Assessment Toolbox.

Joint tissue mechanics (e.g., stress and strain) are believed to have a major involvement in the onset and progression of musculoskeletal disorders, e.g., knee osteoarthritis (KOA). Accordingly, considerable efforts have been made to develop musculoskeletal finite element (MS-FE) models to estimate highly detailed tissue mechanics that predict cartilage degeneration. However, creating such models is time-consuming and requires advanced expertise. This limits these complex, yet promising, MS-FE models to research applications with few participants and makes the models impractical for clinical assessments. Also, these previously developed MS-FE models have not been used to assess activities other than gait. This study introduces and verifies a semi-automated rapid state-of-the-art MS-FE modeling and simulation toolbox incorporating an electromyography- (EMG) assisted MS model and a muscle-force driven FE model of the knee with fibril-reinforced poro(visco)elastic cartilages and menisci. To showcase the usability of the pipeline, we estimated joint- and tissue-level knee mechanics in 15 KOA individuals performing different daily activities. The pipeline was verified by comparing the estimated muscle activations and joint mechanics to existing experimental data. To determine the importance of the EMG-assisted MS analysis approach, results were compared to those from the same FE models but driven by static-optimization-based MS models. The EMG-assisted MS-FE pipeline bore a closer resemblance to experiments compared to the static-optimization-based MS-FE pipeline. Importantly, the developed pipeline showed great potential as a rapid MS-FE analysis toolbox to investigate multiscale knee mechanics during different activities of individuals with KOA.

Internal consistency and factor structure of Jenkins Sleep Scale: cross-sectional cohort study among 80 000 adults.

OBJECTIVES: To assess the internal consistency and construct validity of the Finnish translation of the Jenkins Sleep Scale (JSS) in a large healthy working-age population with diverse work characteristics. DESIGN: Survey-based cross-sectional cohort study. SETTING: Survey conducted by an institute of occupational health. PARTICIPANTS: Employees of 10 towns and 6 hospital districts. PRIMARY AND SECONDARY OUTCOME MEASURES: The internal consistency defined by a Cronbach's alpha. Exploratory and confirmatory factor analyses to evaluate the construct structure of the JSS. RESULTS: Of 81 136 respondents, 14 890 (18%) were men and 66 246 (82%) were women. Their average age was 52.1 (13.2) years. Of the respondents, 41 823 (52%) were sleeping 7 or less hours per night. The mean JSS total score was 6.4 (4.8) points. The JSS demonstrated high internal consistency with an alpha of 0.80 (lower 95% confidence limit 0.80). Exploratory factor analysis supported a one-factor solution with eigenvalue of 1.94. Confirmatory factor analysis showed that all four items were positively correlated with a single common factor explaining 44%-61% of common factor's variance. CONCLUSIONS: The Finnish translation of JSS was found to be a unidimensional scale with good internal consistency. As such, the scale may be recommended as a practicable questionnaire when studying sleep difficulties in a healthy working-age population.

Maturation of collagen fibril network structure in tibial and femoral cartilage of rabbits.

OBJECTIVE: The structure and composition of articular cartilage change during development and growth, as well as in response to varying loading conditions. These changes modulate the functional properties of cartilage. We studied maturation-related changes in the collagen network organization of cartilage as a function of tissue depth. DESIGN: Articular cartilage from the tibial medial plateaus and femoral medial condyles of female New Zealand white rabbits was collected from six age-groups: 4 weeks (n=30), 6 weeks (n=30), 3 months (n=24), 6 months (n=24), 9 months (n=27) and 18 months (n=19). Collagen fibril orientation, parallelism (anisotropy) and optical retardation were analyzed with polarized light microscopy. Differences in the development of depth-wise collagen organization in consecutive age-groups and the two joint locations were compared statistically. RESULTS: The collagen fibril network of articular cartilage undergoes significant changes during maturation. The most prominent changes in collagen architecture, as assessed by orientation, parallelism and retardation were noticed between the ages of 4 and 6 weeks in tibial cartilage and between 6 weeks and 3 months in femoral cartilage, i.e., orientation became more perpendicular-to-surface, and parallelism and retardation increased with changes being most prominent in the deep zone. At the age of 6 weeks, tibial cartilage had a more perpendicular-to-surface orientation in the middle and deep zones than femoral cartilage (P<0.001) and higher parallelism throughout the tissue depth (P<0.001), while femoral cartilage exhibited more parallel-to-surface orientation (P<0.01) above the deep zone after maturation. Optical retardation of collagen was higher in tibial than in femoral cartilage at the ages of 4 and 6 weeks (P<0.001), while at older ages, retardation below the superficial zone in the femoral cartilage became higher than in the tibial cartilage. CONCLUSIONS: During maturation, there is a significant modulation of collagen organization in articular cartilage which occurs earlier in tibial than in femoral cartilage, and is most pronounced in the deep zone.

Skin signs in Ehlers-Danlos syndrome: clinical tests and para-clinical methods.

OBJECTIVE: The criteria for Ehlers-Danlos syndrome (EDS) and the hypermobility syndrome (HMS) should be reliable. Examination for general joint hypermobility has high reliability but there is only sparse information on the reliability of skin tests, and no information on the level of normal skin extensibility. The present study aimed to assess skin signs by means of clinical and para-clinical methods. METHODS: A total of 31 EDS patients and 28 healthy controls were examined blinded and in random order. Inter-examiner analysis of clinical tests for skin extensibility, consistency, scarring, and bruising was performed, followed by analyses of extensibility with the suction cup (SC), consistency with a soft tissue stiffness meter (STSM), and thickness with ultrasonography (US). Semi-quantitative assessment of skin extensibility in healthy controls was incorporated in the tests. RESULTS: The clinical analyses demonstrated kappa values of: 0.72 for extensibility, 0.23 for consistency, 0.53 for scarring, and 0.63 for bruising. Skin extensibility measurements in healthy controls (n = 28) were 2.79 and 2.93 cm (mean + 2 SD), respectively, by the two examiners. There were significant differences between patients with classical-type EDS and controls with respect to skin extensibility by SC (4.91 vs. 12.52 kPa/mm) and skin consistency by STSM (0.59 vs. 0.76 N). We found no difference in skin thickness. CONCLUSION: The reproducibility of the clinical skin tests was substantial to good, apart from the consistency measurements. We suggest that skin consistency is withdrawn as a diagnostic criterion. The upper level for normal skin extensibility should be 3 cm. SC and STSM are promising para-clinical methods, but their diagnostic sensitivity and specificity need to be determined.

Biomechanical, biochemical and structural correlations in immature and mature rabbit articular cartilage.

OBJECTIVE: The structure and composition of articular cartilage change during development and growth. These changes lead to alterations in the mechanical properties of cartilage. In the present study, biomechanical, biochemical and structural relationships of articular cartilage during growth and maturation of rabbits are investigated. DESIGN: Articular cartilage specimens from the tibial medial plateaus and femoral medial condyles of female New Zealand white rabbits were collected from seven age-groups; 0 days (n=29), 11 days (n=30), 4 weeks (n=30), 6 weeks (n=30), 3 months (n=24), 6 months (n=24) and 18 months (n=19). The samples underwent mechanical testing under creep indentation. From the mechanical response, instantaneous and equilibrium moduli were determined. Biochemical analyses of tissue collagen, hydroxylysylpyridinoline (HP) and pentosidine (PEN) cross-links in full thickness cartilage samples were conducted. Proteoglycans were investigated depth-wise from the tissue sections by measuring the optical density of Safranin-O-stained samples. Furthermore, depth-wise collagen architecture of articular cartilage was analyzed with polarized light microscopy. Finite element analyses of the samples from different age-groups were conducted to reveal tensile and compressive properties of the fibril network and the matrix of articular cartilage, respectively. RESULTS: Tissue thickness decreased from approximately 3 to approximately 0.5mm until the age of 3 months, while the instantaneous modulus increased with age prior to peak at 4-6 weeks. A lower equilibrium modulus was observed before 3-month-age, after which the equilibrium modulus continued to increase. Collagen fibril orientation angle and parallelism index were inversely related to the instantaneous modulus, tensile fibril modulus and tissue thickness. Collagen content and cross-linking were positively related to the equilibrium compressive properties of the tissue. CONCLUSIONS: During maturation, significant modulation of tissue structure, composition and mechanical properties takes place. Importantly, the present study provides insight into the mechanical, chemical and structural interactions that lead to functional properties of mature articular cartilage.

Risk factors for the development of hip osteoarthritis: a population-based prospective study.

OBJECTIVES: Potential risk factors and their roles in the aetiology of hip OA are poorly understood. We analysed several alleged risk factors predisposing to hip OA in a 22-yr prospective study. METHODS: A comprehensive health survey was carried out in 1978-80 in a nationally representative sample of adult Finns. In 2000-01, 1286 participants in that survey were invited for re-examination, and 909 agreed to participate. After excluding those with hip OA at the baseline and those who were no longer working, a total of 840 subjects constituted the present study population. Hip OA was diagnosed on the basis of a standardized clinical examination by physicians who applied uniform criteria both at the baseline and at the re-examination phase. RESULTS: After 22 yrs of follow-up, hip OA was diagnosed in 41 subjects (4.9%). Heavy manual labour predicted the risk of developing hip OA [adjusted odds ratio (OR) 6.7; 95% CI 2.3, 19.5]. Permanent damage as a consequence of any musculoskeletal injury was also an independent predictor of hip OA (adjusted OR 5.0; 95% CI 1.9, 13.3). BMI, smoking, alcohol intake and leisure time physical activity were not factors which were predictive for hip OA. CONCLUSION: Heavy physical stress at work and major musculoskeletal injuries are associated with an increased risk of developing clinically diagnosed hip OA.

Skin extensibility and consistency in patients with Ehlers-Danlos syndrome and benign joint hypermobility syndrome.

OBJECTIVES: The reproducibility of clinical tests for skin extensibility and consistency, essential for differentiating between types of Ehlers-Danlos syndrome (EDS) and benign joint hypermobility syndrome (BJHS), is unknown. Paraclinical methods may provide objective differential diagnostic methods. METHODS: Six EDS, 11 BJHS, and 19 controls completed the trial. We analysed the overall inter-examiner agreement on clinical tests for skin extensibility and consistency, in addition to analyses on suction cup (SC) and soft tissue stiffness meter (STSM) methods. RESULTS: Overall agreement on tests for skin extensibility and consistency varied between 0.44 and 0.72. Extensibility evaluated by SC showed an insignificant difference between EDS patients and controls (p = 0.056). Consistency evaluated by STSM showed significant differences (p = 0.001). CONCLUSIONS: Overall inter-examiner agreement on clinical tests for skin extensibility and consistency was below 0.80, which was required a priori to conduct a reproducibility study. Further refinement of tests and a training phase are necessary. The SC and STSM results are encouraging but must be reproduced in a larger study population.

Physical therapy and rehabilitation programs in the management of hip osteoarthritis.

Nonpharmacological treatment programmes are as important as drug treatment in hip osteoarthritis (OA). Drugs (analgesic and nonsteroidal anti-inflammatory drugs) should not be used as sole treatments in hip OA. Patient education and weight reduction are the primary therapeutic approaches. Different types of exercises are beneficial for patients with hip OA. Occupational therapy plays a central role in the management of hip OA patients with functional limitations. More and better-designed trials are needed to evaluate the efficacy of nonpharmacological treatment programmes used in hip OA.

Quantitative study of articular cartilage and subchondral bone remodeling in the knee joint of dogs after strenuous running training.

All tissues of the joint are affected in some way in osteoarthritis because the joint is an interactively functioning unit. Our goal was to investigate the combined responses of articular cartilage and subchondral bone to altered loading conditions to improve our understanding of the physiology of these two components and, ultimately, the pathophysiology of osteoarthritis. A group of 20 female beagle dogs were divided pairwise into runners (n = 10) and controls (n = 10). The running training on a treadmill started at the age of 15 weeks, and during the following 40 weeks the running distance was gradually increased to 40 km/day with a 15 degree uphill inclination. With this daily running distance the beagles ran another 15 weeks. The samples for histology were taken from 11 different locations of the knee joint. Subchondral bone and articular cartilage histomorphometry was carried out in three different regions of the specimens (central, middle, and peripheral regions) using an image-analyzing system and an eyepiece graticule. In all regions of the articular cartilage, both the uncalcified and calcified cartilage showed slightly increased thickness in the runner dogs. The change was more evident in the peripheral and the central areas. The thickness of the subchondral bone plate tended to be higher in runners, too. Bone histomorphometric parameters showed significant signs of increased remodeling. The most notable change was the enlargement of the bone formation surface. The most intense remodeling was usually observed either centrally or peripherally in the articular surface. The strongest increase in trabecular bone volume and thickness of the cartilage was recorded in the femoropatellar area.(ABSTRACT TRUNCATED AT 250 WORDS)

Endurance training associated with slightly lowered serum estradiol levels decreases mineral density of canine skeleton.

The effects of long-term running exercise were studied in 20 beagle dogs. A total of 10 dogs ran from the age of 15 weeks to the age of 70 weeks in a progressive program for up to 40 km/day. A total of 10 sister dogs spent the study period in individual cages. When the dogs were 70 weeks old, bone mineral density of the vertebrae, hip, and radius was analyzed by dual-energy x-ray absorptiometry (DEXA; Lunar) and the vertebrae were also assessed by quantitative computed tomography (QCT; Siemens DR 1). Mineral density was lower in the running dogs than in the controls. The difference was greatest in the spine in the QCT analysis. Blood chemistry analyses revealed that the metabolism of the bone was significantly accelerated. The estradiol levels showed the trend to be reduced in the running group. The beneficial effect of exercise on mineral density has been shown in many earlier studies. However, in this study we demonstrate the possibility of adverse effects of long-term exercise on bone tissue. The change was associated with a decrease of serum estradiol level.

Localization of type X collagen in the intervertebral disc of mature beagle dogs.

Type X collagen expression in intervertebral disc of young adult beagle dogs (n = 10) was studied. Type X collagen was immunostained mainly pericellularly in the central area of the vertebral endplate, but interterritorial staining there was also present. Annulus fibrosus and nucleus pulposus did not usually stain for type X collagen. However, immunostaining of nucleus pulposus for type X collagen with a simultaneous expression of collagen alpha1(X) mRNA was observed in one dog. A weak staining was observed in two other animals with a weak collagen alpha1(X) mRNA signal. In annulus fibrosus, lamellar staining was observed in two dogs. In three animals, type X collagen mRNAs were observed in the outer edge of the annulus fibrosus, but immunohistochemical staining did not always correlate with in situ hybridization signals. In conclusion, intervertebral disc type X collagen was mainly expressed in the cartilaginous endplate. In some apparently healthy animals there was type X collagen expression in the nucleus pulposus and also in the annulus fibrosus.