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Pellicore MJ, Gangi LR, Murphy LA, Lee AJ, Jacobsen T, Kenawy HM, Shah RP, Chahine NO, Ateshian GA, Hung CT. Toward defining the role of the synovium in mitigating normal articular cartilage wear and tear. J Biomech 2023; 148:111472. [PMID: 36753853 PMCID: PMC10295808 DOI: 10.1016/j.jbiomech.2023.111472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 01/27/2023]
Abstract
Cartilage repair has been studied extensively in the context of injury and disease, but the joint's management of regular sub-injurious damage to cartilage, or 'wear and tear,' which occurs due to normal activity, is poorly understood. We hypothesize that this cartilage maintenance is mediated in part by cells derived from the synovium that migrate to the worn articular surface. Here, we demonstrate in vitro that the early steps required for such a process can occur. First, we show that under physiologic mechanical loads, chondrocyte death occurs in the cartilage superficial zone along with changes to the cartilage surface topography. Second, we show that synoviocytes are released from the synovial lining under physiologic loads and attach to worn cartilage. Third, we show that synoviocytes parachuted onto a simulated or native cartilage surface will modify their behavior. Specifically, we show that synoviocyte interactions with chondrocytes lead to changes in synoviocyte mechanosensitivity, and we demonstrate that cartilage-attached synoviocytes can express COL2A1, a hallmark of the chondrogenic phenotype. Our findings suggest that synoviocyte-mediated repair of cartilage 'wear and tear' as a component of joint homeostasis is feasible and is deserving of future study.
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Affiliation(s)
- Matthew J Pellicore
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Lianna R Gangi
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Lance A Murphy
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Andy J Lee
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Timothy Jacobsen
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Hagar M Kenawy
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Roshan P Shah
- Department of Orthopedic Surgery, Columbia University, New York, NY, USA
| | - Nadeen O Chahine
- Department of Biomedical Engineering, Columbia University, New York, NY, USA; Department of Orthopedic Surgery, Columbia University, New York, NY, USA
| | - Gerard A Ateshian
- Department of Orthopedic Surgery, Columbia University, New York, NY, USA; Department of Mechanical Engineering, Columbia University, New York, NY, USA
| | - Clark T Hung
- Department of Biomedical Engineering, Columbia University, New York, NY, USA; Department of Orthopedic Surgery, Columbia University, New York, NY, USA.
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2
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Rytky SJO, Huang L, Tanska P, Tiulpin A, Panfilov E, Herzog W, Korhonen RK, Saarakkala S, Finnilä MAJ. Automated analysis of rabbit knee calcified cartilage morphology using micro-computed tomography and deep learning. J Anat 2021; 239:251-263. [PMID: 33782948 PMCID: PMC8273618 DOI: 10.1111/joa.13435] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 03/04/2021] [Accepted: 03/11/2021] [Indexed: 11/27/2022] Open
Abstract
Structural dynamics of calcified cartilage (CC) are poorly understood. Conventionally, CC structure is analyzed using histological sections. Micro‐computed tomography (µCT) allows for three‐dimensional (3D) imaging of mineralized tissues; however, the segmentation between bone and mineralized cartilage is challenging. Here, we present state‐of‐the‐art deep learning segmentation for µCT images to assess 3D CC morphology. The sample includes 16 knees from 12 New Zealand White rabbits dissected into osteochondral samples from six anatomical regions: lateral and medial femoral condyles, lateral and medial tibial plateaus, femoral groove, and patella (n = 96). The samples were imaged with µCT and processed for conventional histology. Manually segmented CC from the images was used to train segmentation models with different encoder–decoder architectures. The models with the greatest out‐of‐fold evaluation Dice score were selected. CC thickness was compared across 24 regions, co‐registered between the imaging modalities using Pearson correlation and Bland–Altman analyses. Finally, the anatomical CC thickness variation was assessed via a Linear Mixed Model analysis. The best segmentation models yielded average Dice of 0.891 and 0.807 for histology and µCT segmentation, respectively. The correlation between the co‐registered regions was strong (r = 0.897, bias = 21.9 µm, standard deviation = 21.5 µm). Finally, both methods could separate the CC thickness between the patella, femoral, and tibial regions (p < 0.001). As a conclusion, the proposed µCT analysis allows for ex vivo 3D assessment of CC morphology. We demonstrated the biomedical relevance of the method by quantifying CC thickness in different anatomical regions with a varying mean thickness. CC was thickest in the patella and thinnest in the tibial plateau. Our method is relatively straightforward to implement into standard µCT analysis pipelines, allowing the analysis of CC morphology. In future research, µCT imaging might be preferable to histology, especially when analyzing dynamic changes in cartilage mineralization. It could also provide further understanding of 3D morphological changes that may occur in mineralized cartilage, such as thickening of the subchondral plate in osteoarthritis and other joint diseases.
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Affiliation(s)
- Santeri J O Rytky
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
| | - Lingwei Huang
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Petri Tanska
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Aleksei Tiulpin
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland.,Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland.,Ailean Technologies Oy, Oulu, Finland
| | - Egor Panfilov
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
| | - Walter Herzog
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Rami K Korhonen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Simo Saarakkala
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland.,Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
| | - Mikko A J Finnilä
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland.,Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.,Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
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Holzer L, Kraiger M, Talakic E, Fritz G, Avian A, Hofmeister A, Leithner A, Holzer G. Microstructural analysis of subchondral bone in knee osteoarthritis. Osteoporos Int 2020; 31:2037-2045. [PMID: 32472294 PMCID: PMC7497490 DOI: 10.1007/s00198-020-05461-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 05/07/2020] [Indexed: 01/27/2023]
Abstract
UNLABELLED The results of this study show increased formation of bone in the subchondral areas in advanced stages of osteoarthritis of the knee. These changes seem to be influenced by mechanical factors. INTRODUCTION Subchondral bone changes seem to contribute to the progression of knee osteoarthritis (OA). This study aimed to analyze subchondral bone microstructure in specimens of late-stage knee OA in respect to articular cartilage damage, meniscus integrity, and knee joint alignment. METHODS Thirty proximal tibiae of 30 patients (20 female and 10 male) with late-stage OA retrieved during total knee arthroplasty were scanned using a high-resolution micro-computed tomography. The scans were semi-automatically segmented into five volumes of interest. The volumes of interest were then further analyzed using commercially available software. The degree of articular cartilage damage was assessed semi-quantitatively by magnetic resonance imaging before surgery. RESULTS The mean bone fraction volume (bone volume/total volume (BV/TV)) in all weight-bearing locations was significantly higher compared to the non-weight-bearing reference point below the anterior cruciate ligament (p = 0.000). The mean BV/TV in the medial compartment was significantly higher compared to the lateral compartment (p = 0.007). As for the BV/TV in intact menisci, there was a significantly lower subchondral bone fraction volume compared to subluxated or luxated menisci in the medial (p = 0.020) and lateral compartment (p = 0.005). Varus alignment had a significantly higher subchondral BV/TV in the medial compartment, whereas valgus alignment had a significantly higher subchondral BV/TV in the lateral compartment (p = 0.011). CONCLUSIONS The results show significant differences of subchondral bone microstructural parameters in respect to cartilage damage, meniscus' structural integrity, and knee joint alignment. Therefore, subchondral bone changes seem to be a secondary process in the late-stage OA of the knee caused by mechanical changes.
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Affiliation(s)
- L.A. Holzer
- grid.11598.340000 0000 8988 2476Department of Orthopaedics and Trauma, Medical University of Graz, Auenbruggerplatz 5, 8036 Graz, Austria
- AUVA Trauma Center Klagenfurt, Waidmannsdorfer Straße 35, Klagenfurt am Wörthersee, Austria
| | - M. Kraiger
- grid.410413.30000 0001 2294 748XInstitute of Medical Engineering, Graz University of Technology, Graz, Austria
| | - E. Talakic
- grid.11598.340000 0000 8988 2476Division of General Radiology, Department of Radiology, Medical University of Graz, Graz, Austria
| | - G.A. Fritz
- grid.11598.340000 0000 8988 2476Division of General Radiology, Department of Radiology, Medical University of Graz, Graz, Austria
| | - A. Avian
- grid.11598.340000 0000 8988 2476Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Graz, Austria
| | - A. Hofmeister
- grid.11598.340000 0000 8988 2476PreClinical Imaging Group, Center for Biomedical Research, Medical University Graz, Graz, Austria
| | - A. Leithner
- grid.11598.340000 0000 8988 2476Department of Orthopaedics and Trauma, Medical University of Graz, Auenbruggerplatz 5, 8036 Graz, Austria
| | - G. Holzer
- grid.22937.3d0000 0000 9259 8492Department of Orthopaedics and Trauma Surgery, Medical University of Vienna, Vienna, Austria
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Cai H, Hao Z, Xiao L, Wan C, Tong L. The collagen microstructural changes of rat menisci and tibiofemoral cartilages under the influence of mechanical loading: An in vitro wear test of whole joints. Technol Health Care 2018; 25:207-217. [PMID: 28582908 DOI: 10.3233/thc-171323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Knee osteoarthritis (OA) is suggested to be induced by multi-factors, and mechanical environment is regarded as a risky factor. OBJECTIVE To investigate the effect of isolated mechanical factor on cartilage. METHODS An active wear test system was designed to perform parameters-controlled in vitro wear tests on rat knee joints with specific load magnitude, flexion-extension angle, and movement frequency. Six hind limbs of 9-month-old male Sprague-Dawley rats, with an additional spring on the medial side, were worn by using the custom-designed apparatus. Researchers observed both the menisci and tibial cartilages of these hind limbs using multiphoton laser scanning microscopy to analyze the change of the collagen microstructure caused by wear. RESULTS Collagen microstructure of both the medial and lateral meniscus became disordered under cyclic load. Some tissues on the surface of the medial tibial cartilage were removed and the middle layer of the medial compartment displayed cracks. On the contrary, the lateral tibial cartilage was intact. CONCLUSIONS The results implied that cyclic load caused menisci microstructure disarrangement prior to tibial cartilage damage and the collagen structure of mid-layer tibial cartilage failed before that of the superficial layer under the kinematics adopted in the study.
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Affiliation(s)
- Haoliuyang Cai
- Department of Mechanical Engineering, Tsinghua University, Beijing, China
| | - Zhixiu Hao
- Department of Mechanical Engineering, Tsinghua University, Beijing, China.,State Key Laboratory of Tribology, Tsinghua University, Beijing, China
| | - Liying Xiao
- Department of Mechanical Engineering, Tsinghua University, Beijing, China
| | - Chao Wan
- Department of Engineering Mechanics, Tsinghua University, Beijing, China
| | - Lingying Tong
- Department of Mechanical Engineering, Tsinghua University, Beijing, China.,State Key Laboratory of Tribology, Tsinghua University, Beijing, China
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5
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Gerus P, Sartori M, Besier TF, Fregly BJ, Delp SL, Banks SA, Pandy MG, D'Lima DD, Lloyd DG. Subject-specific knee joint geometry improves predictions of medial tibiofemoral contact forces. J Biomech 2013; 46:2778-86. [PMID: 24074941 DOI: 10.1016/j.jbiomech.2013.09.005] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 07/25/2013] [Accepted: 09/05/2013] [Indexed: 11/19/2022]
Abstract
Estimating tibiofemoral joint contact forces is important for understanding the initiation and progression of knee osteoarthritis. However, tibiofemoral contact force predictions are influenced by many factors including muscle forces and anatomical representations of the knee joint. This study aimed to investigate the influence of subject-specific geometry and knee joint kinematics on the prediction of tibiofemoral contact forces using a calibrated EMG-driven neuromusculoskeletal model of the knee. One participant fitted with an instrumented total knee replacement walked at a self-selected speed while medial and lateral tibiofemoral contact forces, ground reaction forces, whole-body kinematics, and lower-limb muscle activity were simultaneously measured. The combination of generic and subject-specific knee joint geometry and kinematics resulted in four different OpenSim models used to estimate muscle-tendon lengths and moment arms. The subject-specific geometric model was created from CT scans and the subject-specific knee joint kinematics representing the translation of the tibia relative to the femur was obtained from fluoroscopy. The EMG-driven model was calibrated using one walking trial, but with three different cost functions that tracked the knee flexion/extension moments with and without constraint over the estimated joint contact forces. The calibrated models then predicted the medial and lateral tibiofemoral contact forces for five other different walking trials. The use of subject-specific models with minimization of the peak tibiofemoral contact forces improved the accuracy of medial contact forces by 47% and lateral contact forces by 7%, respectively compared with the use of generic musculoskeletal model.
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Affiliation(s)
- Pauline Gerus
- Centre for Musculoskeletal Research, Griffith Health Institute, Griffith University, Southport, QLD, Australia.
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6
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Kulmala JP, Äyrämö S, Avela J. Knee extensor and flexor dominant gait patterns increase the knee frontal plane moment during walking. J Orthop Res 2013; 31:1013-9. [PMID: 23417834 DOI: 10.1002/jor.22323] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 01/21/2013] [Indexed: 02/04/2023]
Abstract
High gait-induced knee frontal plane moment is linked with the development of knee osteoarthritis. Gait patterns across the normal population exhibit large inter-individual variabilities especially at the knee sagittal plane moment profile during loading response and terminal stance phase. However, the effects of different gait patterns on this moment remain unknown. Therefore, we examined whether different gait patterns are associated with atypically high knee frontal plane moments. Profiles of knee joint moments divided a sample of 24 subjects into three subgroups (11, 7, 6) through cluster analysis. Kinetics, kinematics, and spatio-temporal parameters were compared among clusters. Subjects who showed a typical sagittal plane moment pattern (n = 11) had 43% lower first peak of knee frontal plane moment compared to the cluster, which showed the dominance of the knee extensor moment during stance phase (n = 7, p < 0.01). In addition, a typical gait pattern cluster had 44% lower second peak knee frontal plane moment than the cluster, which showed the dominance of the knee flexor moment during the terminal stance phase (n = 6, p < 0.05). These findings indicate that different knee strategies driving gait considerably impact knee loading, suggesting that knee extensor and flexor dominant gait patterns demonstrate atypically high knee frontal plane moments. People in these subgroups may, therefore, be at higher risk of developing knee osteoarthritis.
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Affiliation(s)
- Juha-Pekka Kulmala
- Department of Biology of Physical Activity, University of Jyväskylä, Rautpohjan Katu 8A, 40014 Jyväskylä, Finland.
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7
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Horisberger M, Fortuna R, Valderrabano V, Herzog W. Long-term repetitive mechanical loading of the knee joint by in vivo muscle stimulation accelerates cartilage degeneration and increases chondrocyte death in a rabbit model. Clin Biomech (Bristol, Avon) 2013; 28:536-43. [PMID: 23701865 DOI: 10.1016/j.clinbiomech.2013.04.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 04/22/2013] [Accepted: 04/23/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Excessive chronic loading is thought to be one factor responsible for the onset of osteoarthritis. For example, studies using treadmill running have shown an increased risk for osteoarthritis, thereby suggesting that muscle-induced joint loading may play a role in osteoarthritis onset and progression. However, in these studies, muscle-induced loading was not carefully quantified. Here, we present a model of controlled muscular loading which allows for the accurate quantification of joint loading. The aim of this study was to evaluate the effects of long-term, cyclic, isometric and dynamic, muscle-induced joint loading of physiologic magnitude but excessive intensity on cartilage integrity and cell viability in the rabbit knee. METHODS 24 rabbits were divided into an (i) eccentric, (ii) concentric, or (iii) isometric knee extensor contraction group (50 min of cyclic, submaximal stimulation 3 times/week for four weeks=19,500 cycles) controlled by the stimulation of a femoral nerve cuff electrode on the right hind limb. The contralateral knee was used as a non-loaded control. The knee articular cartilages were analysed by confocal microscopy for chondrocyte death, and histologically for Mankin Score, cartilage thickness and cell density. FINDINGS All loaded knees had significantly increased cell death rates and Mankin Scores compared to the non-loaded joints. Cartilage thicknesses did not systematically differ between loaded and control joints. INTERPRETATION Chondrocyte death and Mankin Scores were significantly increased in the loaded joints, thereby linking muscular exercise of physiologic magnitude but excessive intensity to cartilage degeneration and cell death in the rabbit knee.
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Affiliation(s)
- Monika Horisberger
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Alberta, Canada
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8
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Poulet B, Westerhof TAT, Hamilton RW, Shefelbine SJ, Pitsillides AA. Spontaneous osteoarthritis in Str/ort mice is unlikely due to greater vulnerability to mechanical trauma. Osteoarthritis Cartilage 2013; 21:756-63. [PMID: 23467034 DOI: 10.1016/j.joca.2013.02.652] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 02/13/2013] [Accepted: 02/21/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Relative contributions of genetic and mechanical factors to osteoarthritis (OA) remain ill-defined. We have used a joint loading model found to produce focal articular cartilage (AC) lesions, to address whether genetic susceptibility to OA in Str/ort mice is related to AC vulnerability to mechanical trauma and whether joint loading influences spontaneous OA development. We also develop finite element (FE) models to examine whether AC thickness may explain any differential vulnerability to load-induced lesions. METHODS Right knees of 8-week-old Str/ort mice were loaded, AC integrity scored and thickness compared to CBA mice. Mechanical forces engendered in this model and the impact of AC thickness were simulated in C57Bl/6 mice using quasi-static FE modelling. RESULTS Unlike joints in non-OA prone CBA mice, Str/ort knees did not exhibit lateral femur (LF) lesions in response to applied loading; but exhibited thicker AC. FE modeling showed increased contact pressure and shear on the lateral femoral surface in loaded joints, and these diminished in joints containing thicker AC. Histological analysis of natural lesions in the tibia of Str/ort joints revealed that applied loading increased OA severity, proteoglycan loss and collagen type II degradation. CONCLUSION Genetic OA susceptibility in Str/ort mice is not apparently related to greater AC vulnerability to trauma, but joint loading modifies severity of natural OA lesions in the medial tibia. FE modelling suggests that thicker AC in Str/ort mice diminishes tissue stresses and protects against load-induced AC lesions in the LF but that this is unrelated to their genetic susceptibility to OA.
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Affiliation(s)
- B Poulet
- Lifestyle Research Group, The Royal Veterinary College, Royal College Street, University of London, NW1 0TU, UK.
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9
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Roemhildt ML, Beynnon BD, Gardner-Morse M, Anderson K, Badger GJ. Tissue modification of the lateral compartment of the tibio-femoral joint following in vivo varus loading in the rat. J Biomech Eng 2013; 134:104501. [PMID: 23083201 DOI: 10.1115/1.4007453] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study describes the first application of a varus loading device (VLD) to the rat hind limb to study the role of sustained altered compressive loading and its relationship to the initiation of degenerative changes to the tibio-femoral joint. The VLD applies decreased compressive load to the lateral compartment and increased compressive load to the medial compartment of the tibio-femoral joint in a controlled manner. Mature rats were randomized into one of three groups: unoperated control, 0% (sham), or 80% body weight (BW). Devices were attached to an animal's leg to deliver altered loads of 0% and 80% BW to the experimental knee for 12 weeks. Compartment-specific material properties of the tibial cartilage and subchondral bone were determined using indentation tests. Articular cartilage, calcified cartilage, and subchondral bone thicknesses, articular cartilage cellularity, and degeneration score were determined histologically. Joint tissues were sensitive to 12 weeks of decreased compressive loading in the lateral compartment with articular cartilage thickness decreased in the peripheral region, subchondral bone thickness increased, and cellularity of the midline region decreased in the 80% BW group as compared to the 0% BW group. The medial compartment revealed trends for diminished cellularity and aggregate modulus with increased loading. The rat-VLD model provides a new system to evaluate altered quantified levels of chronic in vivo loading without disruption of the joint capsule while maintaining full use of the knee. These results reveal a greater sensitivity of tissue parameters to decreased loading versus increased loading of 80% BW for 12 weeks in the rat. This model will allow future mechanistic studies that focus on the initiation and progression of degenerative changes with increased exposure in both magnitude and time to altered compressive loads.
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Affiliation(s)
- M L Roemhildt
- McClure Musculoskeletal Research Center, Department of Orthopedics and Rehabilitation, College of Medicine, University of Vermont, Burlington, VT 05405, USA.
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10
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Roemhildt ML, Beynnon BD, Gauthier AE, Gardner-Morse M, Ertem F, Badger GJ. Chronic in vivo load alteration induces degenerative changes in the rat tibiofemoral joint. Osteoarthritis Cartilage 2013; 21:346-57. [PMID: 23123358 PMCID: PMC3556233 DOI: 10.1016/j.joca.2012.10.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 10/16/2012] [Accepted: 10/25/2012] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We investigated the relationship between the magnitude and duration of sustained compressive load alteration and the development of degenerative changes in the rat tibiofemoral joint. METHODS A varus loading device was attached to the left hind limb of mature rats to apply increased compression to the medial compartment and decreased compression to the lateral compartment of the tibiofemoral joint of either 0% or 100% body weight for 0, 6 or 20 weeks. Compartment-specific assessment of the tibial plateaus included biomechanical measures (articular cartilage aggregate modulus, permeability and Poisson's ratio, and subchondral bone modulus) and histological assessments (articular cartilage, calcified cartilage, and subchondral bone thicknesses, degenerative scoring parameters, and articular cartilage cellularity). RESULTS Increased compression in the medial compartment produced significant degenerative changes consistent with the development of osteoarthritis (OA) including a progressive decrease in cartilage aggregate modulus (43% and 77% at 6 and 20 weeks), diminished cellularity (38% and 51% at 6 and 20 weeks), and increased histological degeneration. At 20 weeks, medial compartment articular cartilage thickness decreased 30% while subchondral bone thickness increased 32% and subchondral bone modulus increased 99%. Decreased compression in the lateral compartment increased calcified cartilage thickness, diminished region-specific subchondral bone thickness and revealed trends for reduced cellularity and decreased articular cartilage thickness at 20 weeks. CONCLUSIONS Altered chronic joint loading produced degenerative changes consistent with those observed clinically with the development of OA and may replicate the slow development of non-traumatic OA in which mechanical loads play a primary etiological role.
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Affiliation(s)
| | - B. D. Beynnon
- College of Medicine, Department of Orthopaedics and Rehabilitation, University of Vermont,
| | - A. E. Gauthier
- College of Medicine, Department of Orthopaedics and Rehabilitation, University of Vermont,
| | - M. Gardner-Morse
- College of Medicine, Department of Orthopaedics and Rehabilitation, University of Vermont,
| | - F. Ertem
- College of Medicine, Department of Orthopaedics and Rehabilitation, University of Vermont,
| | - G. J. Badger
- Department of Medical Biostatistics, University of Vermont,
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Abstract
This review primarily focuses on how the macromolecular composition and architecture of articular cartilage and its unique biomechanical properties play a pivotal role in the ability of articular cartilage to withstand mechanical loads several magnitudes higher than the weight of the individual. Current findings on short-term and long-term effects of exercise on human articular cartilage are reviewed, and the importance of appropriate exercises for individuals with normal and diseased or aberrated cartilage is discussed.
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Affiliation(s)
- Harpal K Gahunia
- Orthopedic Science Consulting Services, Oakville, Ontario, Canada.
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