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Medial Meniscus (medial + meniscus)
Selected AbstractsIs the circumferential tensile modulus within a human medial meniscus affected by the test sample location and cross-sectional area?JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2000Kate Lechner Quantifying the material properties of the human menisci is paramount to understanding their biomechanical functions within the knee. One important intrinsic material property governing the biomechanical functions of the meniscus is the circumferential tensile modulus. The purpose of this study was to determine if the circumferential tensile modulus of the human medial meniscus depends on the location and thickness of the sample tested. The following three hypotheses were tested: (a) the circumferential location (anterior, central, and posterior) does not significantly affect the tensile modulus, (b) the radial location (inner to outer) significantly affects the tensile modulus, and (c) the thicknes (cross-sectional area) significantly affects the tensile modulus. Test samples, whose length was oriented in parallel with the circumferential collagen fibers, were collected from different circumferential and radial locations throughout 30 human medial menisci. Samples of three different thicknesses (0.5, 1.5, and 3.0 mm) were taken from three equal groups of 10 menisci (i.e., one thickness per group). The circumferential tensile modulus was measured under quasi-statc loading. Statistical analysis showed no significant effect of the circumferential or radial location of the sample on the circumferential tensile modulus. This indicates that an overall circumferential tensile modulus may be calculated for the human medial meniscus by averaging the values determined at the various locations. However, the thickness of the test sample had a significant effect on the measured circumferential tensile modulus: the modulus varied inversely with the thickness. Thus, moduli determined from test samples that are too small in cross-sectional area overestimate the effective modulus of the tissue on the whole, and the cross-sectional area of the sample must be considered when determining a representative circumferential tensile modulus for the medial meniscus in a human knee. [source] A cranial intercondylar arthroscopic approach to the caudal medial femorotibial joint of the horseEQUINE VETERINARY JOURNAL, Issue 1 2009T. Muurlink Summary Reason for performing study: Current noninvasive techniques for imaging the soft tissue structures of the stifle have limitations. Arthroscopy is commonly used for the investigation and treatment of stifle pain. Cranial and caudal arthroscopic approaches to the femorotibial joints are used. However, complete examination of the axial aspect of the medial femorotibial joint (MFTJ) is not possible currently. Objective: To develop a cranial approach to the caudal pouch of the MFTJ and to assess whether it would allow a more complete examination of the compartment and facilitate the caudomedial approach. Method: The regional anatomy was reviewed and the technique developed on cadavers. A series of nonrecovery surgeries were performed to evaluate the procedure, which was then used in 7 clinical cases. Advantages compared to existing techniques and complications encountered were recorded. Results: Successful entry into the caudal pouch of the MFTJ was achieved in 20 of 22 cadaver legs, 8 of 8 joints of nonrecovery surgery horses and 6 of 7 clinical cases operated. The caudal ligament of the medial meniscus could be visualised, along with other axial structures of the caudal joint pouch. The technique was used to facilitate a caudomedial approach and allowed better triangulation within the joint space. Complications were minor and included puncture of the caudal joint capsule and scoring of the axial medial femoral condyle. Conclusions and potential relevance: It is possible to access the caudal pouch of the MFTJ arthroscopically using a cranial intercondylar approach. The technique has advantages when compared to existing techniques and is associated with few significant complications. A cranial approach to the caudal pouch of the MFTJ could complement existing techniques and be useful clinically. [source] Medial meniscus posterior root attachment injury and degeneration: MRI findingsJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 4 2006AO Jones Summary The posterior root attachment of the medial meniscus is readily identifiable on MRI. Unless specifically reviewed, injuries involving this structure may be overlooked. Significant meniscal root pathology may cause functional incompetence of the meniscus, with consequent early onset cartilage degeneration and osteoarthritis. This review article emphasizes the importance of positive identification of an intact meniscal root and illustrates the known association of meniscal root injury or tear with medial extrusion of the medial meniscus by greater than 3 mm beyond the joint margin. [source] Kinematics of the ACL-deficient canine knee during gait: Serial changes over two yearsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2004Scott Tashman Abstract The ACL-deficient dog is a model for investigating the development and progression of mechanically driven osteoarthrosis of the knee. ACL loss creates dynamic instability in the ACL-deficient knee which presumably leads to progressive joint degeneration, but the nature of this instability over the time course of disease development is not well understood. The goal of this study was to characterize three-dimensional motion of the canine knee during gait, before and serially for two years after ACL transection. Canine tibial-femoral kinematics were assessed during treadmill gait before and serially for two years after ACL transection (ACL-D group; 18 dogs) or sham transection (ACL-I group; five dogs). Kinematic data was collected at 250 frames/s using a biplane video-radiographic system. Six degree-of-freedom motions of the tibia relative to the femur were calculated, and values immediately prior to pawstrike as well as the maximum, minimum, midpoint and range of motion during early/mid stance were extracted. Between-group differences relative to baseline (pre-transection) values, as well as changes over time post-transection, were determined with a repeated-measures ANCOVA. In the ACL-D group, peak anterior tibial translation (ATT) increased by 10 mm (p < 0.001), and did not change over time (p = 0.76). Pre-pawstrike ATT was similar to ACL-intact values early on (2,4 months) but then increased significantly over time, by 3.5 mm (p < 0.001). The range of ab/adduction motion nearly doubled after ACL loss (from 3.3° to 6.1°). The magnitude (midpoint) of knee adduction also increased significantly over time (mean increase 3.0°; p = 0.036). All changes occurred primarily between 6 and 12 months. There were no significant differences between groups in the transverse plane, and no significant changes over time in the ACL-I group. In summary, peak anterior tibial translation and coronal-plane instability increased immediately after ACL loss, and did not improve with time. ATT just prior to pawstrike and mean knee adduction throughout stance became progressively more abnormal with time, with the greatest changes occurring between 6 and 12 months after ACL transection. This may be due to overload failure of secondary restraints such as the medial meniscus, which has been reported to fail in a similar timeframe in the ACL-deficient dog. The relationships between these complex mechanical alterations and the rate of OA development/progression are currently under investigation. © 2004 Published by Elsevier Ltd. on behalf of Orthopaedic Research Society. [source] Is the circumferential tensile modulus within a human medial meniscus affected by the test sample location and cross-sectional area?JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2000Kate Lechner Quantifying the material properties of the human menisci is paramount to understanding their biomechanical functions within the knee. One important intrinsic material property governing the biomechanical functions of the meniscus is the circumferential tensile modulus. The purpose of this study was to determine if the circumferential tensile modulus of the human medial meniscus depends on the location and thickness of the sample tested. The following three hypotheses were tested: (a) the circumferential location (anterior, central, and posterior) does not significantly affect the tensile modulus, (b) the radial location (inner to outer) significantly affects the tensile modulus, and (c) the thicknes (cross-sectional area) significantly affects the tensile modulus. Test samples, whose length was oriented in parallel with the circumferential collagen fibers, were collected from different circumferential and radial locations throughout 30 human medial menisci. Samples of three different thicknesses (0.5, 1.5, and 3.0 mm) were taken from three equal groups of 10 menisci (i.e., one thickness per group). The circumferential tensile modulus was measured under quasi-statc loading. Statistical analysis showed no significant effect of the circumferential or radial location of the sample on the circumferential tensile modulus. This indicates that an overall circumferential tensile modulus may be calculated for the human medial meniscus by averaging the values determined at the various locations. However, the thickness of the test sample had a significant effect on the measured circumferential tensile modulus: the modulus varied inversely with the thickness. Thus, moduli determined from test samples that are too small in cross-sectional area overestimate the effective modulus of the tissue on the whole, and the cross-sectional area of the sample must be considered when determining a representative circumferential tensile modulus for the medial meniscus in a human knee. [source] Diagnostic accuracy of positive contrast computed tomography arthrography for the detection of injuries to the medial meniscus in dogs with naturally occurring cranial cruciate ligament insufficiencyJOURNAL OF SMALL ANIMAL PRACTICE, Issue 7 2009M. S. Tivers Objective: To assess the usefulness of computed tomography arthrography of the stifle in diagnosing meniscal tears in dogs with cranial cruciate ligament insufficiency. Methods: A prospective clinical study was performed. Dogs were included if they had evidence of cranial cruciate ligament insufficiency or persistent or recurrent lameness following surgery for cranial cruciate ligament insufficiency. Dogs were sedated for a computed tomography scan of the affected stifle, orientated in the dorsal plane. A survey computed tomography scan was followed by a computed tomography arthrogram. A stifle arthrotomy was performed, and the surgical findings were recorded. The computed tomography scans were reviewed by three blinded reviewers, and the results were compared to the surgical findings. Results: Twenty-one computed tomography arthrograms from 20 dogs were included. At surgery, damage to the medial meniscus was identified in 14 stifles. Initial interpretation of computed tomography arthrography images was 57 to 64 per cent sensitive and 71 to 100 per cent specific for diagnosing medial meniscal injuries. Interpretation of the images on retrospective analysis was 71 per cent sensitive and 100 per cent specific, with an accuracy of 0·857. Clinical Significance: The accuracy of stifle computed tomography arthrography for the diagnosis of tears to the medial meniscus was found to be good. It is a minimally invasive and repeatable technique, which does not require general anaesthesia or specialist training to obtain the images. The ability to reliably diagnose meniscal injury without the need for surgery may be advantageous, particularly in dogs which had previously had surgery for cranial cruciate ligament insufficiency. [source] Attenuation of osteoarthritis progression by reduction of discoidin domain receptor 2 in miceARTHRITIS & RHEUMATISM, Issue 9 2010Lin Xu Objective To investigate whether the reduction of discoidin domain receptor 2 (DDR-2), a cell membrane tyrosine kinase receptor for native type II collagen, attenuates the progression of articular cartilage degeneration in mouse models of osteoarthritis (OA). Methods Double-heterozygous (type XI collagen,deficient [Col11a1+/,] and Ddr2 -deficient [Ddr2+/,]) mutant mice were generated. Knee joints of Ddr2+/, mice were subjected to microsurgical destabilization of the medial meniscus. Conditions of the articular cartilage from the knee joints of the double-heterozygous mutant and surgically treated mice were examined by histology, evaluated using a modified Mankin scoring system, and characterized by immunohistochemistry. Results The rate of progressive degeneration in knee joints was dramatically reduced in the double-heterozygous mutant mice compared with that in the type XI collagen,deficient mice. The progression in the double-heterozygous mutant mice was delayed by ,6 months. Following surgical destabilization of the medial meniscus, the progressive degeneration toward OA was dramatically delayed in the Ddr2+/, mice compared with that in their wild-type littermates. The articular cartilage damage present in the knee joints of the mice was directly correlated with the expression profiles of DDR-2 and matrix metalloproteinase 13. Conclusion Reduction of DDR-2 expression attenuates the articular cartilage degeneration of knee joints induced either by type XI collagen deficiency or by surgical destabilization of the medial meniscus. [source] Fibroblast growth factor 2 is an intrinsic chondroprotective agent that suppresses ADAMTS-5 and delays cartilage degradation in murine osteoarthritisARTHRITIS & RHEUMATISM, Issue 7 2009Shi-Lu Chia Objective We have previously identified in articular cartilage an abundant pool of the heparin-binding growth factor, fibroblast growth factor 2 (FGF-2), which is bound to the pericellular matrix heparan sulfate proteoglycan, perlecan. This pool of FGF-2 activates chondrocytes upon tissue loading and is released following mechanical injury. In vitro, FGF-2 suppresses interleukin-1,driven aggrecanase activity in human cartilage explants, suggesting a chondroprotective role in vivo. We undertook this study to investigate the in vivo role of FGF-2 in murine cartilage. Methods Basal characteristics of the articular cartilage of Fgf2,/, and Fgf2+/+ mice were determined by histomorphometry, nanoindentation, and quantitative reverse transcriptase,polymerase chain reaction. The articular cartilage was graded histologically in aged mice as well as in mice in which osteoarthritis (OA) had been induced by surgical destabilization of the medial meniscus. RNA was extracted from the joints of Fgf2,/, and Fgf2+/+ mice following surgery and quantitatively assessed for key regulatory molecules. The effect of subcutaneous administration of recombinant FGF-2 on OA progression was assessed in Fgf2,/, mice. Results Fgf2,/, mice were morphologically indistinguishable from wild-type (WT) animals up to age 12 weeks; the cartilage thickness and proteoglycan staining were equivalent, as was the mechanical integrity of the matrix. However, Fgf2,/, mice exhibited accelerated spontaneous and surgically induced OA. Surgically induced OA in Fgf2,/, mice was suppressed to levels in WT mice by subcutaneous administration of recombinant FGF-2. Increased disease in Fgf2,/, mice was associated with increased expression of messenger RNA of Adamts5, the key murine aggrecanase. Conclusion These data identify FGF-2 as a novel endogenous chondroprotective agent in articular cartilage. [source] Use of biodegradable urethane-based adhesives to appose meniscal defect edges in an ovine model: a preliminary studyAUSTRALIAN VETERINARY JOURNAL, Issue 6 2008JR FIELD Objective To evaluate the biological response to two urethane-based adhesives used to repair full thickness meniscal wounds created in the partially vascularised (red-white) zone. Design An ovine bilateral meniscal defect model was used to evaluate the initial biological response of the meniscal cartilage and synovium over a 1-month period. A 10-mm full-thickness defect was created in the medial meniscus of each femorotibial joint. The defects were either left untreated or repaired using the urethane-based adhesives. Synovial fluid, synovial membrane and the meniscal cartilages were retrieved at necropsy for cytological and histological assessment. Results The ovine model proved to be a suitable system for examining meniscal repair. Untreated defects showed no tissue apposition or cellular healing response, whereas all eight defects repaired with the two urethane-based adhesive formulations showed signs of repair and tissue regeneration with indications of cell infiltration and new collagen deposition in and around the polymer. No adverse cellular response to the adhesives was observed in the meniscal defect or in the synovial membrane and fluid. Conclusion Trauma to the knee commonly results in tears to the meniscal cartilage, with the majority of these occurring in the partially vascularised (red-white) or non-vascularised (white) zones of the meniscus. Repair, and subsequent healing, of these tears is poor because of the reduced vascularity and limited surgical access. The present data indicate that an ovine model is a suitable system for examining meniscal repair, and that development of urethane-based adhesives offers a strategy that may be clinically effective for the treatment of these injuries. [source] | ||||||||||