Surface Of Condyle Research Articles

Statistical modeling of the equine third metacarpal bone incorporating morphology and bone mineral density.

The objective of this study was to describe the three-dimensional shape and subchondral bone mineral density (BMD) variation of the equine distal third metacarpal bone (MC3) using a statistical shape model. The association between form and function builds upon previous two-dimensional observations of MC3 epiphyseal structure. It was expected that the main source of variation would be an increase in overall MC3 bone size, correlated to an increase in subchondral BMD. Geometry and bone mineral density was obtained from CT image data of 40 healthy Thoroughbred horses. This was used to create a statistical shape model, in which the first ten components described 75% of the variation in geometry and BMD. The first principal component described an increase in overall size of the MC3 distal epiphysis, coupled with higher BMD on the disto-palmar and dorso-proximal surfaces. The second component was qualitatively described as an increased convexity of the sagittal ridge at the dorsal junction of the epiphysis and the metaphysis, coupled to increased BMD in that region. The third component showed an increase in lateral condylar surface area relative to medial condylar area. As the condyle reduced in relative surface area, the BMD at both dorsal condyles increased. The statistical shape analysis produced a compact description of 3-D shape and sub-chondral bone mineral density variation for the third metacarpal bone. This study uniquely illustrates the shape variations in a sample population of MC3 bones, and the corresponding changes in subchondral BMD.

Characterisation of wear areas on UHMWPE total knee replacement prostheses through study of their areal surface topographical parameters

Total knee replacement is one of the most common elective surgeries in the world, and presents a number of challenges related to the wear of ultra-high molecular weight polyethylene (UHMWPE). This paper presents an analysis of the surface topographical properties of the worn and unworn condylar surfaces on a small cohort of both wear simulated and retrieved prostheses of varying designs. A number of measurement points were taken on each prostheses in a mixture of worn and unworn areas through the use of focus-variation microscopy (FVM), a non-contact method of surface measurement. Surface areal parameters were extracted from this data to analyse and search for patterns within the data. It was found that in general, worn implant surfaces appear to show smoother, less peak dominated surfaces than unworn area. It was also found that wear simulated and retrieved implants display similar characteristics of surface topography. In addition, variation was noted between different designs of TKR device, with posterior stabilised designs found to be peak dominated and cruciate retaining type implants being valley dominated.

Effect of Boron on the Repair of Osteochondral Defect and Oxidative Stress in Rats: an Experimental Study.

The aim of this study was to investigate the effect of boron on the repair of osteochondral defect and also on some antioxidant and oxidant parameters of both cartilage tissue and blood. A total of 24 adult male Wistar rats weighing between 350 and 400g were used in the study. Animals were randomly divided into control (n = 8), boron (n = 8) and hyaluronic acid (HA) groups (n = 8). Under general anesthesia, a cylindrical full-thickness osteochondral defect 1.5mm in diameter and 2mm in depth was formed using a drill on the anterior side of the articular surface of the femur condyle. Boron group received 0.1ml (10mg/kg) of boron and HA group received 0.1ml of HA, whereas control group received 0.1ml of physiological saline solution. All agents administered intraarticular route and once a week for four times. At the end of the third month, the animals were euthanized and blood and joint tissue malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and catalase levels were measured. Defected femoral condyles of the rats were removed for a histopathological examination. Histopathology revealed that the total cartilage repair score of the HA group was better than those detected in boron and control groups. Blood and articular cartilage GSH, SOD, and catalase levels were higher in the boron and HA groups as compared to the control group, while MDA level was lower compared to the control group. In conclusion, it was suggested that boron was not as effective as HA in the repair of osteochondral defect, but its antioxidant property was superior to HA.

Knee Pain - Football, Basketball

HISTORY: 16 year-old high school football and basketball athlete was referred to Sports Medicine. He could not recall a specific injury, but had 2 months of recurrent pain and swelling with high-impact activities. No neuropathic, mechanical, nor instability symptoms. No prior knee orthopedic history. PHYSICAL EXAMINATION: Inspection showed slight genu valgum and small right knee effusion. No pain with palpation of all bony and soft tissue landmarks of the knee. Active range of motion was pain free and symmetric for knee flexion and extension. Strength was intact at 5/5 hip flexion, knee extension and knee flexion. Provocative maneuvers showed no pain with bounce and McMurrays, firm 1+ endpoint with Lachmans, anterior drawer, and posterior drawer. He was stable and symmetric with no laxity or pain during varus and valgus stressing of the knee at 0 and 30 degrees of flexion. No pain with patellar compression and negative dial testing. DIFFERENTIAL DIAGNOSIS: Includes meniscus pathology, plica syndrome, patellofemoral pain, osteochondritis dissecans (OCD), stress injury TESTS AND RESULTS: 1. Standing knee xrays showed medial femoral condyle OCD with knee effusion and loose body in suprapatellar space. 2. MRI of right knee showed 1.7 x 1.3 cm osteochondral defect at the central weight-bearing surface of the medial femoral condyle with displaced osteochondral fragment in the suprapatellar bursa. FINAL WORKING DIAGNOSIS: Grade IV osteochondritis dissecans lesion TREATMENT AND OUTCOMES: 1. Recommended non-weight bearing and medial unloader brace requested while physical therapy initiated. 2. Diagnostic arthroscopy for loose body removal and biopsy for matrix-induced chondrocyte implantation. 3. Low impact activities only, physical therapy and medial unloader brace with ambulation until harvested cells ready for implantation. 4. Matrix-induced autologous chondrocyte implantation was performed after 6 weeks of cell culturing. 5. Athlete treated with post-operative rehabilitation protocol. 6. MRI at 6 months demonstrated interval progression of healing medial femoral condyle OCD. 7. Athlete will continue post-operative rehabilitation protocol and will be assessed for readiness for sport progression at 12 and 18 months.

Longitudinal survey for high density mineralised protrusions identified by 3D dess MRI in patients of the osteoarthritis initiative

Purpose: The structural and physiological integrity of the bone-cartilage interface is essential to maintaining joint health. Phenomena that disrupt this boundary can compromise whole joint function and are a major factor in the development of osteoarthritis (OA), particularly in the knee. Early diagnosis of such maladies may offer a predictive biomarker of joint destruction. Microcracks in the subchondral bone plate including the articular calcified cartilage (ACC) are in some cases repaired with a high density mineralised infill material. This material may also extend from the mineralising front into hyaline articular cartilage (HAC) as a high density mineralised protrusion (HDMP). Such features are likely to impair biomechanical performance of surrounding tissues. Their formation can occur in the absence of symptomatic OA and they are potentially a primary cause of OA. Recent reports have confirmed the presence of HDMPs in human ex- and in-vivo knee joints and their detectability with clinical MRI. Here we present the first longitudinal MRI study prospecting for HDMPs in the human knee. Methods: Twenty-one patients were selected from the osteoarthritis initiative (OAI) progression cohort for whom bilateral knee MRI data were available at five consecutive annual visits. Sagitally-acquired dual echo steady state MRI images were assessed for the presence of HDMP-like features at baseline. Incidences were recorded and categorised to one of six regions according to bone and laterality: medial femoral condyle (MFC), lateral femoral condyle (LFC), intercondylar fossa of femur (ICF), medial tibial condyle (MTC), lateral tibial condyle (LTC) and intercondylar ridge of tibia (ICT). Imaging data from follow-up visits were used to monitor the development of features over time. Results: Seventeen patients were found to possess MRI features identified as HDMPs in at least one knee with incidence being unilateral in 5 and bilateral in 12 cases. A total of 58 features were found, ranging from 1 to 5 in a single joint. Features were found in all six regions of the knee joint but distribution between regions was inequitable with 73% being located somewhere on the femur (ICF = 36%; LFC = 25%; MFC = 12%) and only 27% on the tibia (LTC = 23%; MTC = 2%; ICT = 2%). Of those HDMPs identified at baseline, the percentage still present at each subsequent annual visit was 96, 90, 85 and 81, respectively. Morphology of those still visible varied greatly; some remained similar in appearance while others altered substantially, for example, changing in size and shape. Some appeared to have fragmented, forming clusters within HAC. Figure 1 shows an example of a HDMP located on the articular surface of the medial femoral condyle. The material extends from the subchondral bone surface initially. It can be seen breaking away and moving gradually through HAC over time. Conclusions: Observation of features in regions of high mechanical stress and noting their disappearance over time is suggestive of a role in arthropathy. Fine particles of fragmented HDMP may abrade HAC and damage surrounding tissue. The potential for mineral features to fragment may account for apparent clustering of features over time, or they may be discrete incidences. Longevity of features throughout the study duration suggests fragmentation is slow and not guaranteed. Disappearance may indicate destruction or may be caused by average effects. The lower proportion of HDMPs in tibiae may indicate the bone is less susceptible to HDMP formation, or they may be shorter lived. The appearances of HDMPs in clinical scans were consistent with reported ex-vivo studies. Clinical DESS yields high contrast between signal intensities of mineral (low yield) and HAC (high yield) and the features described should be considered a potential imaging biomarker for the prediction of joint destruction in some forms of OA.

Trabecular structural changes in the mandibular condyle caused by degenerative osteoarthritis: a comparative study by cone-beam computed tomography imaging.

Temporomandibular osteoarthritis causes pain and loss of function. In advanced cases, it may also result in destruction of joint cartilage surfaces and bone structure. This study was performed to examine the potential changes in the condylar trabecular bone structure in patients with temporomandibular osteoarthritis. Condylar trabecular structures were compared between 35 healthy patients and 35 patients with temporomandibular osteoarthritis by a box-counting method using fractal dimensional analysis on cone-beam computed tomography images. The average fractal dimensions of patients with temporomandibular osteoarthritis and healthy patients were 1.18 and 1.23, respectively. This difference was statistically significant (p ≤ 0.05). Our results add to the existing preliminary knowledge regarding the osteoporotic changes that occur in the trabecular structure under the subchondral bone, which is normally not seen on radiographic images, as well as the destruction and remodeling that occur on the condyle surface, which is visible on radiographic images.

Age Predicts Disruption of the Articular Surface of the Femoral Condyles in Knee OCD: Can We Reduce Usage of Arthroscopy and MRI?

The purpose of this study was to determine if patient age could accurately identify disrupted articular cartilage overlying an osteochondritis dissecans (OCD) lesion of the femoral condyle in adolescents. This could have important implications for imaging and treatment decisions. All patients from 2001 to 2014 who were arthroscopically treated for a femoral condyle OCD were included in this Institutional Review Board-approved study. Exclusion criteria were trochlear and patellar OCD lesions, idiopathic arthritis, and traumatic osteochondral injuries. Arthroscopy was performed to visualize and probe the articular surface. Arthroscopic and magnetic resonance imaging (MRI) findings were recorded as "intact" or "disrupted" cartilage. Extra-articular drilling was performed when the articular cartilage was intact. There were 119 patients (81 male, 68%) with 139 OCD lesions in 136 knees. The mean age at time of surgery was 13.0 years (range, 7.2 to 19.3 y). At arthroscopy, 115 knees had intact cartilage and 24 had disrupted cartilage. There was a significant difference in age between patients with intact versus disrupted cartilage at arthroscopy (12.5 vs. 15.3 y; P<0.0001). Eighty-eight OCD lesions had MRIs preoperatively, showing 69 as intact and 19 (24%) disrupted. MRI reading for cartilage status had 94% sensitivity and 97% specificity. Multivariable regression analysis revealed that age (P<0.01) and MRI status (P<0.0001) were strong predictors of cartilage status. Sixteen years was the critical age in which both sensitivity was maximized and false positive probability was minimized. Over the age of 17 years, 7 of 7 (100%) had disrupted cartilage. Age alone was 100% sensitive for children below the age of 10, and 96% sensitive below the age of 13. Age was a good predictor of cartilage status in both younger (<13 y) and older (≥17 y) patients in this study. For patients in the mid-range group (13 through 16 y), age alone is not an adequate predictor of cartilage status, but adding MRI increased accuracy. Age can be used to stratify patients and thereby influence diagnostic and treatment strategies. Level IV.

Variability in the Clock Face View Description of Femoral Tunnel Placement in ACL Reconstruction Using MRI-Based Bony Models

Though controversial, the "clock face view" of the intercondylar notch remains a way some surgeons communicate regarding placement of the femoral tunnel in anterior cruciate ligament reconstruction. The purpose of this study was to quantify the differences in angle measurement between several previous descriptions of the clock face view by using a new reference standard. Three-Tesla magnetic resonance imaging (MRI) was used to scan 10 human knees to create three-dimensional MRI-based bony models which were used for measurements. A standardized clock face view was developed with the knee flexed to 90° using the junction of the cartilage and cortex of the medial and lateral surfaces of medial and lateral femoral condyles as the 3 o'clock and 9 o'clock, respectively, with the 12 o'clock established as the midpoint of the roof of the intercondylar notch. With the knee viewed at 90° of flexion, an "idealized" femoral tunnel position was plotted on the medial wall of the lateral femoral condyle at 30° (corresponding to the 10 o'clock or 2 o'clock position). The clock faces as described by Edwards et al, Heming et al, and Mochizuki et al were each then overlaid on this same model and the difference in measurement calculated. The average angles measured when the previously described clock faces were projected onto the idealized clock face view comparing a mark made at 30° were 47.7°, 7.2°, and 49.8° for the methods described by Edwards et al, Heming et al, and Mochizuki et al, respectively (all p < 0.001). Significant variation exists between angle measurements in simulated femoral tunnel placement based on the varying descriptions of the intercondylar clock face.

Assessment of condylar morphology and position using MSCT in an Asian population.

The purpose of the present study was to investigate the volume, surface, morphometric index (MI), and position of the condyle in a normal population by applying Mimics 17.0 software. Then, the difference between left and right sides, sex, and age can be explored, which will contribute to establish the reference value of condylar morphology and position in normal individuals, and help us to study characteristics of condylar morphology and position in abnormal individuals. Three-hundred subjects were enrolled in our study from the radiology department of Shanghai Jiao Tong University Affiliated Sixth People's Hospital. They were divided into three groups according to the age: group 1 (18-24years old), group 2 (25-34years old), and group 3 (35-44years old). Each group included 100 subjects (with 50 males and 50 females). They were examined using multislice computed tomography (MSCT) after that. All images of condyle were reconstructed by Mimics 17.0 software, so as to measure the volume, surface, and MI of condyle, and to analyze the position of condyle in the articular fossa by means of joint spaces. The differences of condylar volume, surface, and MI between left and right sides were not obvious (P> 0.05). The condylar volume and surface were greater in males than females (P< 0.05), while their condylar MI existed no difference (P> 0.05). No statistical differences were found in volume and surface among three age groups. However, the MI of group 1 was statistically lower than that of group 3 (P< 0.05). On the other hand, no significant differences were found between left and right condylar position (P> 0.05). Nevertheless, there were significant differences of condylar position regarding the gender and age (P< 0.05). This study showed no significant differences in condylar morphology and position between left and right sides, but factors of gender and age were proven to have a certain influence on the morphology and position of the condyle. This information can be clinically useful in establishing the diagnostic criteria for condylar morphology and position in the normal Asian population. Examination of condylar morphology and position is important for evaluating the abnormalities and bony changes that affect the temporomandibular joint (TMJ). So, this will be conducive to the diagnosis and the evaluation of therapeutic effect of temporomandibular joint diseases. Also, it is important to evaluate these indexes prior to commencing orthodontic treatment, because TMJ abnormalities play a critical role in orthodontic treatment planning.

Bone morphology and morphometry of the lateral femoral condyle is a risk factor for ACL injury.

The purpose of this study was to investigate the influence of the knee lateral compartment bony morphology and morphometry on risk of sustaining an anterior cruciate ligament (ACL) injury. A total of 400 age and sex-matched patients (200 ACL-ruptured and 200 ACL-intact) were included. The lateral femoral and tibial bone morphology and morphometric parameters were measured on knee lateral radiographs, taken at 30° of knee flexion with overlapping of the femoral condyles. Radiographic measurements included: anteroposterior-flattened surface of the femur's lateral condyle (XY); femur's diaphysis anteroposterior distance (A); anteroposterior distance of the femur's lateral condyle (B); height of the femur's lateral condyle (C); anteroposterior distance of the tibial plateaus (AB); tibial slope. In addition, three morphological ratios were calculated: B/AB; B/XY; XY/AB (Porto ratio). Most of bone morphological parameters were different between genders (P < 0.05). ACL-ruptured female subjects showed statistical significant smaller condyle heights (C), smaller distances of the flattened surface of the distal femoral condyle (XY), smaller tibial plateau anteroposterior distances (AB), and higher XY/AB ratio (P < 0.05). ACL-ruptured male subjects had statistical significant smaller condyle height (C), anteroposterior distance of the femur's lateral condyle (B), tibial plateau anteroposterior distances (AB), and tibial slope (P < 0.05). Multivariate logistic regression model showed that five morphological parameters (A, XW, XY, XZ, and AB) were significantly associated with ACL rupture (AUC = 0.967, P < 0.001). Calculated ratios (XY/AB; B/AB; B/XY) showed a significant accuracy in identifying individuals with ACL injury (P < 0.001). The most important finding of this study was that the calculated ratios (XY/AB; B/AB; B/XY) showed a significant accuracy in identifying the individuals with and without an ACL injury. Within this line, alonger flat surface of thelateral femoral condyle or higher Porto ratio (XY/AB) is associated with a lower the risk of ACL injury. Moreover, when considering the combination of five primary bone morphology and morphometric parameters (A, XW, XY, XZ, and AB), the accuracy in identifying these individuals was excellent (AUC = 0.967). These findings may contribute to injury risk assessment, sports participation, and injury prevention counseling and surgical planning refining by identifying high-risk patients who would benefit from the addition of associated procedures to the anatomic ACL reconstruction aiming the improvement of knee stability and decrease the risk of further injuries. III, case-control study.

KNEE CARTILAGE AND SYNOVIAL MEMBRANE STRUCTURAL CHANGES DURING TIBIA DISTRACTION WITH PLATING

Purpose of the study — to analyze the changes in knee articular cartilage and synovial membrane during distraction external fixation of the tibia in combination with plating.Material and methods. Articular cartilage and synovial membrane of the knee joint were studied using histomorphometry methods in 9 mongrel dogs during distraction external fixation of the tibia combined with plating. Tibia and fibula osteotomies were performed at the border of middle and upper third, plate was fixed on tibia diaphysis. Lengthening was achieved at rate of 1 mm per day in four stages during 21–28 days. Animals were withdrawn from experiment in 30 and 90 days. After autopsy of knee joints the authors excised sections of synovial membrane from suprapatellar area, articular cartilage with underlying subchondral bone from loadable surface of femoral condyles. Thickness of articular cartilage, its area and volumetric density of chondrocytes was measured, proportion of chondrocytes within isogenic groups from the overall number of chondrocytes as well as proportion of empty lacunae. In synovial membrane the authors measured thickness of surface layer and numeric density of micro vessels. Articular cartilage of 5 intact animals was used as a control group.Results. After 30 days of plate fixation a hyperplasia of the integument layer, mild synovitis, and hypervascularization were observed in synovial membrane. Density of micro vessels increased to 363.93±33.71 (control group — 335.05±28.88). The authors also observed subperineural and endoneural edema as well as destruction of nerve fibers in subsynovial layer. Articular cartilage retained the zonal structure. Destructive changes were manifested by fibers separation in the superficial part of surface zone and by partial loss of chondrocytes. The following parameters were reduced: cartilage thickness, area and volumetric density of chondrocytes, proportion of isogenic groups; empty lacunae exceeded the values in controls by 18.2%. After 90 days of plate fixation, thinning of the cover layer of synovial membrane was reported. The numerical density of micro vessels decreased to 325.81±36.39. In nerves of subsynovial layer the edema and vacuolization of myelin sheaths of preserved nerve fibers as well as the formation of Büngner bands in place of degenerating ones were detected. Synovitis was not observed. Fibers separation of extracellular substance in upper superficial part of the surface cartilage zone was retained. There was a tendency to increase in cartilage thickness, area and volumetric density of chondrocytes, proportion of isogenic groups; and to decrease of empty lacunae number.Conclusion. The histological changes in the articular cartilage during distraction external fixation of the tibia in combination with plating corresponded to the initial stages of osteoarthritis of grades 1—2 according to histological classification of International Society for Study of Osteoarthritis (2006) and were accompanied by hypovascularization and denervation of synovial membrane.

Effects of the Vertical Malocclusion Types on the Dimension of the Mandibular Condyle.

This study aimed to find the relationship between mandibular condyle morphology and dental malocclusion in patients with anterior open bite, deep bite, and normal overbite. Eighty patients were included in this retrospective study. All patients had skeletal Class II pattern. The initial panoramic radiographs of patients were digitized using a software program, and groups were compared in terms of condylar height, width, area, and perimeter. In addition, changes in the condyle surface shape were detected using the same panoramic radiographs. The mean width was 1.55±0.06 cm in the open bite group, 1.48±0.06 cm in the deep bite group, and 1.38±0.07 cm in the normal bite group. The mean height was 2.17±0.08 cm in the open bite group, 1.95±0.06 cm in the deep bite group, and 1.97±0.08 cm in the normal bite group. The mean area was 2.33±0.13 cm2 in the open bite group, 2.09±0.11 cm2 in the deep bite group, and 2.04±0.14 cm2 in the normal bite group. There was no statistical significant difference between groups in terms of condyle measurements and condyle surface shapes. The results suggest that the vertical malocclusion type does not have a considerable effect on the mandibular condyle measurements and surface shapes.

Lateral Intercondylar Ridge: Is it a reliable landmark for femoral ACL insertion?: An anatomical study

BackgroundIncorrect femoral tunnel placement is the most common cause of graft failure during Anterior Cruciate Ligament (ACL) Reconstruction. A reliable landmark can minimize errors. AimTo identify whether the Lateral Intercondylar Ridge (LIR) is a consistent anatomical structure and define its relationship with the femoral ACL insertion. Materials and methodsPhase 1: we studied 23 femoral dry bone specimens macroscopically. Using a digital microscribe, the medial surface of the lateral femoral condyle was reconstructed (3D) to evaluate whether there was an identifiable bony ridge.Phase 2: 7 cadaveric specimens with intact soft tissues were dissected to identify the femoral ACL insertion. A 3D reconstruction of the femoral ACL insertion and the surface allowed us to define the relationship between the LIR and the ACL insertion. ResultsAll specimens had a defined LIR on the medial surface of the lateral femoral condyle. The ridge was consistently located just anterior to the femoral ACL insertion. The ACL footprint was present in the depression between the ridge and the Inferior Articular Cartilage Margin (IACM). The mean distance from the midpoint of the IACM to the LIR was 10.1 mm. ConclusionsThis is the first study to use the microscribe to digitally reconstruct the medial surface of the lateral femoral condyle. It shows that the LIR is a consistent anatomical structure that defines the anterior margin of the femoral ACL insertion, which guides femoral tunnel placement. Our findings support the ruler technique, which is a commonly used method for anatomic single bundle ACL reconstruction.

Displacement Analysis of the Human Knee Joint Based on the Spatial Kinematic Model by Using Vector Method

Abstract Kinematic model of the human knee joint, considered as one-degree-of-freedom spatial parallel mechanism, is used to analyse the spatial displacement of the femur with respect to the tibia. The articular surfaces of femoral and tibia condyles are modelled, based on selected references, as spherical and planar surfaces. The condyles are contacted in two points and are guided by three ligaments modelled as binary links with constant lengths. In particular, the mechanism position problem is solved by using the vector method. The obtained kinematic characteristics are adequate to the experimental results presented in the literature. Additionally, the screw displacements of relative motion in the knee joint model are determined.

Protective effect of glucosamine cyclohexyl ester on osteoarthritis in rat via targeting expressions of matrix metalloproteinase and tissue inhibitor of metalloproteinases-1

Purpose: To investigate the therapeutic effect of glucosamine cyclohexyl ester on osteoarthritis (OA) in a rat model.Methods: Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot assays were used to analyze the effect of glucosamine cyclohexyl ester on changes in mRNA and protein expressions of matrix metalloproteinase and tissue inhibitor of metalloproteinases-1 in isolated rat chondrocytes, and in a rat model of OA. The rat model of OA was prepared by injecting monoiodoacetate to Sprague-Dawley rats via intra-articular route.Results: Treatment of the chondrocytes with glucosamine cyclohexyl ester for 48 h prevented interleukin-1 β (IL-1β)-mediated increases in mRNA and protein expressions in matrix metalloproteinases-1, -3 and -13, and also blocked IL-1β-induced decreases in mRNA and protein expressions of tissue inhibitor of metalloproteinase-1. Glucosamine cyclohexyl ester treatment also blocked the onset of morphological changes such as irregular surface, adhesion of tissues andpresence of osteophytes in the femoral condyle surface of the OA rats. Mankin score for control, OA and glucosamine cyclohexyl ester treatment groups were 0.98 ± 0.15, 8.35 ± 0.88 and 2.39 ± 0. 67 (p = 0.002), respectively. Treatment of OA rats with glucosamine cyclohexyl ester also inhibited increases in the activities of matrix metalloproteinases-1, -3 and -13, and decreases of tissue inhibitor of metalloproteinase-1 mRNA and protein expressions. Treatment of chondrocytes and OA rats with IL-1β caused no significant changes in the levels of H3K27 and H4K8.Conclusion: These results show that glucosamine cyclohexyl ester prevents OA by targeting the expressions of matrix metalloproteinases-1, -3 and -13 and tissue inhibitor of metalloproteinases-1.Keywords: Metalloproteinases, Interleukin, Mankin score, Osteoarthritis, Cartilage

Morphology of the thoracic limb of goat as evidenced by gross osteology and radiology.

The objective of this study was to provide the detailed normal gross osteology and radiographic anatomy of the thoracic limb in goats as a reference for clinical use and in biomedical research. Radiography of the thoracic limb was performed in five small East African goats. Radiographic findings were correlated with bone specimens from four adult small East African goats. The scapula was narrow. The major tubercle was large and extended proximally above the head of the humerus. The lateral supracondylar crest was less prominent. The lateral and medial epicondyles of the humerus were almost of the same size. The lateral surface of the lateral condyle of the humerus presented a prominent depression for the origin of extensors of the carpus and digits. The cranially located radial notch was deep seated and the radial tuberosity was represented by a rough area located nearer to the head of the radius. The fifth metacarpal bone was seen in all animals. The morphology of the thoracic limb of small East African goats indicated the presence of powerful extensor muscles and is restricted to forward and backward movements as an adaptation to terrestrial lifestyle.

The effects of captive versus wild rearing environments on long bone articular surfaces in common chimpanzees (Pan troglodytes).

The physical environments of captive and wild animals frequently differ in substrate types and compliance. As a result, there is an assumption that differences in rearing environments between captive and wild individuals produce differences in skeletal morphology. Here, this hypothesis is tested using a sample of 42 captive and wild common chimpanzees (Pan troglodytes). Articular surface areas of the humerus, radius, ulna, femur, and tibia were calculated from linear breadth measurements, adjusted for size differences using Mosimann shape variables, and compared across sex and environmental groups using two-way ANOVA. Results indicate that the articular surfaces of the wrist and knee differ between captive and wild chimpanzees; captive individuals have significantly larger distal ulna and tibial plateau articular surfaces. In both captive and wild chimpanzees, males have significantly larger femoral condyles and distal radius surfaces than females. Finally, there is an interaction effect between sex and rearing in the articular surfaces of the femoral condyles and distal radius in which captive males have significantly larger surface areas than all other sex-rearing groups. These data suggest that long bone articular surfaces may be sensitive to differences experienced by captive and wild individuals, such as differences in diet, body mass, positional behaviors, and presumed loading environments. Importantly, these results only find differences due to rearing environment in some long bone articular surfaces. Thus, future work on skeletal morphology could cautiously incorporate data from captive individuals, but should first investigate potential intraspecific differences between captive and wild individuals.

Biostable scaffolds of polyacrylate polymers implanted in the articular cartilage induce hyaline-like cartilage regeneration in rabbits.

PurposeTo study the influence of scaffold properties on the organization of in vivo cartilage regeneration. Our hypothesis was that stress transmission to the cells seeded inside the pores of the scaffold or surrounding it, which is highly dependent on the scaffold properties, determines the differentiation of both mesenchymal cells and dedifferentiated autologous chondrocytes.Methods4 series of porous scaffolds made of different polyacrylate polymers, previously seeded with cultured rabbit chondrocytes or without cells, were implanted in cartilage defects in rabbits. Subchondral bone was injured during the surgery to allow blood to reach the implantation site and fill the scaffold pores.ResultsAt 3 months after implantation, excellent tissue regeneration was obtained, with a well-organized layer of hyaline-like cartilage at the condylar surface in most cases of the hydrophobic or slightly hydrophilic series. The most hydrophilic material induced the poorest regeneration. However, no statistically significant difference was observed between preseeded and non-preseeded scaffolds. All of the materials used were biocompatible, biostable polymers, so, in contrast to some other studies, our results were not perturbed by possible effects attributable to material degradation products or to the loss of scaffold mechanical properties over time due to degradation.ConclusionsCartilage regeneration depends mainly on the properties of the scaffold, such as stiffness and hydrophilicity, whereas little difference was observed between preseeded and non-preseeded scaffolds.

Biomimetic design and fabrication of multilayered osteochondral scaffolds by low-temperature deposition manufacturing and thermal-induced phase-separation techniques

Integrative osteochondral repair is a useful strategy for cartilage-defect repair. To mimic the microenvironment, it is necessary that scaffolds effectively mimic the extracellular matrix of natural cartilage and subchondral bone. In this study, biomimetic osteochondral scaffolds containing an oriented cartilage layer, a compact layer, and a three-dimensional (3D)-printed core-sheath structured-bone layer were developed. The oriented cartilage layer was designed to mimic the structural and material characteristics of native cartilage tissue and was fabricated with cartilage matrix-chitosan materials, using thermal-induced phase-separation technology. The 3D-printed core-sheath structured-bone layer was fabricated with poly(L-lactide-co-glycolide)/β-tricalcium phosphate-collagen materials by low-temperature deposition technology, using a specially designed core-sheath nozzle, and was designed to mimic the mechanical characteristics of subchondral bone and improve scaffold hydrophilicity. The compact layer was designed to mimic the calcified-layer structure of natural cartilage to ensure the presence of different suitable microenvironments for the regeneration of bone and cartilage. A dissolving-bonding process was developed to effectively combine the three parts together, after which the bone and cartilage scaffolds exhibited good mechanical properties and hydrophilicity. Additionally, goat autologous bone mesenchymal stem cells (BMSCs) were isolated and then seeded into the bone and cartilage layers, respectively, and following a 1 week culture in vitro, the BMSC-scaffold constructs were implanted into a goat articular-defect model. Our results indicated that the scaffolds exhibited good biocompatibility, and 24 weeks after implantation, the femoral condyle surface was relatively flat and consisted of a large quantity of hyaloid cartilage. Furthermore, histological staining revealed regenerated trabecular bone formed in the subchondral bone-defect area. These results provided a new method to fabricate biomimetic osteochondral scaffolds and demonstrated their effectiveness for future clinical applications in cartilage-defect repair.

Loading and Form in the Mammalian Jaw Joint

The synovial articulation between the dentary and squamosal bones, usually referred to as the temporomandibular joint (TMJ), is a defining feature of the Class Mammalia. The mandibular component of this joint is a secondary cartilage that develops in a membranous matrix and contributes to growth of the mandible. While resembling the growth cartilage of long bones, the mandibular condylar cartilage differs in that it also must function as the articular surface of the mammalian jaw joint, a function mediated by a fibrous thickening of the perichondrium. Another difference from typical growth cartilage is that cells are closely packed and not aligned in columns. This feature permits the direction of growth to be altered. Perhaps because of its origin from membranous tissue, the mandibular condyle is notably sensitive to mechanical loading, particularly during the period of growth. Loading of the TMJ arises from contraction of the jaw muscles, but the magnitude and orientation of loading vary according to the muscle combination used. In this contribution we summarize and synthesize studies on condylar loading assessed using strain gages affixed to the condylar neck of rabbits (Oryctolagus cuniculus) and pigs (Sus scrofa) under normal and altered conditions, correlating the findings with condylar morphology. During normal mastication young adult rabbits evince nearly vertical compressive strain on the condylar neck. Reduction of muscle force using botulinum toxin diminished and reoriented the strain, and these changes were accompanied by a striking loss of bone in the condylar head and neck. The paralyzed side condyle tended to be smaller than that of the healthy side, suggesting that condylar surface area did not increase normally, but the thickness of the cartilage layer was unaffected, implying no change in length of the cartilage process. Like rabbits, pigs show compressive strain on the condylar neck during mastication. During the growth process, the orientation of masticatory compressive strain alters from posterior‐superior in younger animals to anterior‐superior in older pigs. Studies correlating condylar strain with cartilage proliferation showed a tendency for proliferation to decrease as condylar compressive strain increased. A procedure (distraction osteogenesis) used clinically to increase mandibular length was found to lower the magnitude and reorient condylar strain. Unlike the adult rabbits, these juvenile pigs responded to lowered loads with increased growth, but the direction was altered in correspondence with the reorientation of masticatory strain. Collectively, these studies illustrate the dependence of mandibular morphology on the specifics of species, age, and especially masticatory mechanics.Support or Funding InformationSupported by DE08513, DE14336, DE018142 from NIDCR.