Joint motion in the absence of normal loading does not maintain normal articular cartilage

Palmoski, Marshall J.; Colyer, Robert A.; Brandt, Kenneth D.

doi:10.1002/art.1780230310

Cited by 243 publications

(122 citation statements)

References 25 publications

(4 reference statements)

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“…In the contact areas, i.e., at the patellar surface of the femur and on the condylar summits of the femur, the loss of GAGs was not prominent. This suggests that contact forces, even within the cast, suffice to better maintain normal cartilage matrix (9). Further evidence of this is the finding that in the knees contralateral to the casted ones, the increase in weight-bearing caused an increase in the GAG content of the articular cartilage.…”

Section: Discussionmentioning

confidence: 99%

Weight bearing controls glycosaminoglycan concentration and articualr cartilage thickness in the knee joints of young beagle dogs

Kiviranta

Jurvelin

Tammi

et al. 1987

Arthritis & Rheumatism

204

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Casting of the right knee (stifle) joints of young beagle dogs for 11 weeks caused up to 48% reduction in the glycosaminoglycan (GAG) concentration of the uncalcified articular cartilage, as assessed by a new microspectrophotometric method. The GAGS were depleted mainly in the superficial zone of the cartilage. Although the thickness of the uncalcified cartilage was not decreased, the calcified cartilage under the tidemark was thinned by 6 2 5 % at the femoral condyles. The increased weight-bearing in the limb opposite the one in the splint caused uncalcified cartilage thickness to be augmented by 19% and GAG concentration by 25-35 % in the intermediate, deep, and calcified zones of the summits of the femoral condyles; the changes were smaller in other, less loaded parts of the joint. It is concluded that in young dogs, increased weight-bearing augments local proteoglycan content of the articular cartilage matrix, while unloading reduces it.

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Section: Discussionmentioning

confidence: 99%

Weight bearing controls glycosaminoglycan concentration and articualr cartilage thickness in the knee joints of young beagle dogs

Kiviranta

Jurvelin

Tammi

et al. 1987

Arthritis & Rheumatism

204

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“…This was apparent when the uronic acid values were related either to the water content or to the DNA content of the tissues, since these were essentially the same in unloaded cartilage as in loaded cartilage. The similarity of water content values in loaded and unloaded cartilage suggests that normal unloaded cartilage is different from atrophic (10,25) or osteoarthritic cartilage (26,27) in which the uronic acid content is decreaseld but the water content is increased. Presumably, the hyperhydration in damaged cartilage reflects an abnormality in the collagen network of the tissue that permits the hydrophilic proteoglycans to expand their molecular domains (28,29).…”

Section: Discussionmentioning

confidence: 99%

Composition and glycosaminoglycan metabolism of articular cartilage from habitually loaded and habitually unloaded sites

Slowman

Brandt

1986

Arthritis & Rheumatism

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The uronic acid (proteoglycan, PG) content of cartilage from habitually unloaded sites of normal canine femoral condyles has been shown to be lower than that from habitually loaded regions, even though the glycosaminoglycan (GAG) synthesis is similar. We investigated whether the GAG degradation in unloaded cartilage would be greater than that in loaded cartilage, and we obtained comparative biochemical data concerning the PGs and organization of the extracellular matrix of noi-ma1 loaded and unloaded cartilage. PG extractability (qetermined by sequential guanidinium chloride extracts of cartilage), percentage of PGs forming large aggregates, and hydrodynamic size of the PG monomers (determined by Sepharose 2B chromatography) were essentially the same in loaded and unloaded cartilage. As expected, the uronic acid content of unloaded cartilage was 20% lower than that of loaded cartilage (P < 0.02), while the water and DNA contents of the 2 tissues were not statistically different. There was no difference in the rate of net "S04-GAG synthesis in organ cultures of loaded and unloaded cartilage. Moreover, there was no appreciable difference in the rates of "S04-GAG degradation of loaded and unloaded cartilage, ais determined by "SO4 pulse-chase studies. We have previously shown that selective cyclic compressive stresses applied in vitro to cartilage from loaded areas of canine femoral condyles may increase "S04-GAG synthesis. The present results suggest that the rates of GAG metabolism in loaded and unloaded cartilage under atmospheric pressure in vitro may not reflect the rates which exist in articular joints under compressive loads in vivo.A number of reports have suggested that a causal relationship exists between the proteoglycan (PG) content of connective tissue and the mechanical stress to which it is subjected. Thus, the glycosaminoglycan (GAG) content of load-bearing areas of dermis (l), articular cartilage (2-5), and tendon (6,7) is greater than that of habitually unloaded areas of the same tissues. Furthermore, it is clear that such differences can be modulated in vivo (8,9). An increase in compressive loading of the normal canine shoulder has been shown to produce an in vivo increase in the chondroitin sulfate content of the articular cartilage of the humeral head (9). Conversely, when loading of articular cartilage is reduced, e.g., by immobilization of the ipsilateral limb, net PG synthesis (8,lO) is decreased and the glycosaminoglycan content (1 1 GAG IN LOADED AND UNLOADED CARTILAGE 89either increased or decreased net GAG biosynthesis, depending on the duration of loading (18).In preliminary studies, we found that the level of net GAG synthesis in normal canine femoral condylar cartilage from habitually loaded areas was comparable with that in cartilage from habitually unloaded areas of the same joint (4). Since the uronic acid content of cartilage from unloaded sites is lower than that of cartilage from loaded regions, we hypothesized that the rate of GAG degradation in unloaded cartilage would be g...

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“…Many studies have shown that mechanical loading of articular cartilage affects the metabolism of chondrocytes and its biochemical composition [1,32,37]. Both animal and human studies have shown that the GAG content is higher in cartilage that is habitually loaded [19,33] or has a higher level of activity [39], whereas immobilization results in a reversible decrease in cartilage PG content [18,30].…”

Section: Introductionmentioning

confidence: 99%

Does Periacetabular Osteotomy Have Depth-related Effects on the Articular Cartilage of the Hip?

Hingsammer

Miller

Millis

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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Background Osteoarthritis may result from abnormal mechanics leading to biochemically mediated degradation of cartilage. In a dysplastic hip, the periacetabular osteotomy (PAO) is designed to normalize the mechanics and our initial analysis suggests that it may also alter the cartilage biochemical composition. Articular cartilage structure and biology vary with the depth from the articular surface including the concentration of glycosaminoglycans (GAG), which are the charge macromolecules that are rapidly turned over and are lost in early osteoarthritis. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) enables noninvasive measurement of cartilage GAG content. The dGEMRIC index represents an indirect measure of GAG concentration with lower values indicating less GAG content. GAG content can normally vary with mechanical loading; however, progressive loss of GAG is associated with osteoarthritis. By looking at the changes in amounts of GAG in response to a PAO at different depths of cartilage, we may gain further insights into the types of biologic events that are occurring in the joint after a PAO. Questions/purposes We (1) measured the GAG content in the superficial and deep zones for the entire joint before and after PAO; and (2) investigated if the changes in the superficial and deep zone GAG content after PAO varied with different locations within the joint. Methods This prospective study included 37 hips in 37 patients (mean age 26 ± 9 years) who were treated with periacetabular osteotomy for symptomatic acetabular dysplasia and had preoperative and 1-year follow up dGEMRIC scans. Twenty-eight of the 37 also had 2-year scans. Patients were eligible if they had symptomatic acetabular dysplasia with lateral center-edge angle \ 20°a nd no or minimal osteoarthritis. The change in dGEMRIC after surgery was assessed in the superficial and deep cartilage zones at five acetabular radial planes. Results The mean ± SD dGEMRIC index in the superficial zone fell from 480 ± 137 msec preoperatively to 409 ± 119 msec at Year 1 (95% confidence interval [CI], À87 to À54; p \0.001) and recovered to 451 ± 115 msec at Year 2 (95% CI, 34-65; p \ 0.001), suggesting that there is a transient event that causes the biologically sensitive superficial layer to lose GAG. In the deep acetabular cartilage zone, dGEMRIC index fell from 527 ± 148 msec preoperatively to 468 ± 143 msec at Year 1 (95% CI, À66 to À30; p\0.001) and recovered to 494 ± 125 msec at Year 2 (95% CI, 5-32; p = 0.008). When each acetabular radial plane was looked at separately, the change from before surgery to 1 year after was confined to zones around the superior part of the joint.

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Joint motion in the absence of normal loading does not maintain normal articular cartilage

Cited by 243 publications

References 25 publications

Weight bearing controls glycosaminoglycan concentration and articualr cartilage thickness in the knee joints of young beagle dogs

Weight bearing controls glycosaminoglycan concentration and articualr cartilage thickness in the knee joints of young beagle dogs

Composition and glycosaminoglycan metabolism of articular cartilage from habitually loaded and habitually unloaded sites

Does Periacetabular Osteotomy Have Depth-related Effects on the Articular Cartilage of the Hip?

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