Impact-absorbing properties of the human knee

Article · December 1987with7 Reads
Source: PubMed
Abstract
A biomechanical study has been carried out on 20 cadaveric knees to investigate their load-absorbing mechanism. The impact load was applied using a weight falling onto the transected proximal femur and the force transmitted through the knee was measured at the transected distal tibia using a load transducer. The peak force transmitted increased as, sequentially, meniscus, articular cartilage and subchondral bone were damaged or removed. The most striking result was found in an implanted knee replacement where the transmitted force reached 180% of that in the intact knee. The results show that the joint has an impact-absorbing property in each segment and that in the osteoarthritic knee there is less absorption of shock than in the normal knee. The high impact force in an implanted knee suggests that microfractures of the cancellous bone might be expected and may produce loosening.
    • Today we mainly tread on firm surfaces wearing shoes and a greater proportion of the impact forces from walking need to be compensated by our bodies. The human body offers several shock absorbing structures to protect bones, joints, and brain from the forces produced by every heel contact (Hoshino and Wallace, 1987). Besides the construction of our feet and spine, muscles provide the most important element that absorbs impact loads on joints during locomotion (Voloshin and Wosk, 1982; Wee and Voloshin, 2013).
    [Show abstract] [Hide abstract] ABSTRACT: Safety shoe designs are primarily based on safety requirements. But all-day comfort should not be luxury: Heel strike associated impact loads on joints need to be compensated by active muscular effort and safety shoes should support this protective function of muscle activation. In 10 healthy men, 12 trunk and leg muscles were analyzed with surface electromyography. Subjects walked on a walkway while wearing different safety shoes with the test shoes being equipped with exchangeable cushioning heel inserts according to individuals' body weight. While wearing the optimally cushioned shoes the cumulative muscle activity per distance travelled dropped clearly compared to the regular safety shoes, demonstrating reduced muscular effort. Also, the heel strike associated amplitude peak of back muscles occurred earlier within the stride while wearing the test shoes. Thus weight-balanced cushioning heel inserts in safety shoes proved able to reduce muscle strain, logically delaying muscular fatigue and extending muscular joint protection.
    Full-text · Article · Mar 2015
    • Meniscal rupture seems to be a strong risk factor in the development and progression of knee osteoarthritis. Meniscectomy increases knee osteoarthritis risk twofold [1,22]. Modifiable risk factors are natural target for clinical efforts in managing knee degeneration.
    [Show abstract] [Hide abstract] ABSTRACT: Meniscus degeneration is a common problem in the human knee. Meniscal diseases can significantly alter the quality of life. Thermal analysis of human meniscus extracted during surgery can provide insight into the degenerative process. The aim of present study was to characterise the water loss from the investigated biological samples caused by altered metabolism, and compare the thermogravimetric properties of normal, moderately, and severely degenerated meniscus samples. Although total water content was similar in normal, moderately and severely degenerated meniscal cartilages (70.26, 75.51 and 76.29% respectively), there was a significant difference in activation energy (44.92, 51.44 and 62.04 kJ M-1). This can be attributed to the difference in chemical composition of meniscus fibrocartilagenous matrix between the healthy and degenerated samples.
    Article · Jan 2015 · International Journal of Primatology
    • In fact, the deformation of menisci plays a critical role in dissipating loads imposed upon the knee joint. For example, when human cadaveric knee joints are loaded after the removal of their menisci, the articular cartilage and subchondral bone experience nearly 120% of the force typically distributed through the joint [62]. Moreover, in kangaroo knees, their relatively supple and broad menisci deform greatly under load, enhancing both joint congruence and safety factors [58] .
    [Show abstract] [Hide abstract] ABSTRACT: Eutherian mammals and saurischian dinosaurs both evolved lineages of huge terrestrial herbivores. Although significantly more saurischian dinosaurs were giants than eutherians, the long bones of both taxa scale similarly and suggest that locomotion was dynamically similar. However, articular cartilage is thin in eutherian mammals but thick in saurischian dinosaurs, differences that could have contributed to, or limited, how frequently gigantism evolved. Therefore, we tested the hypothesis that sub-articular bone, which supports the articular cartilage, changes shape in different ways between terrestrial mammals and dinosaurs with increasing size. Our sample consisted of giant mammal and reptile taxa (i.e., elephants, rhinos, sauropods) plus erect and non-erect outgroups with thin and thick articular cartilage. Our results show that eutherian mammal sub-articular shape becomes narrow with well-defined surface features as size increases. In contrast, this region in saurischian dinosaurs expands and remains gently convex with increasing size. Similar trends were observed in non-erect outgroup taxa (monotremes, alligators), showing that the trends we report are posture-independent. These differences support our hypothesis that sub-articular shape scales differently between eutherian mammals and saurischian dinosaurs. Our results show that articular cartilage thickness and sub-articular shape are correlated. In mammals, joints become ever more congruent and thinner with increasing size, whereas archosaur joints remained both congruent and thick, especially in sauropods. We suggest that gigantism occurs less frequently in mammals, in part, because joints composed of thin articular cartilage can only become so congruent before stress cannot be effectively alleviated. In contrast, frequent gigantism in saurischian dinosaurs may be explained, in part, by joints with thick articular cartilage that can deform across large areas with increasing load.
    Full-text · Article · Oct 2013
    • By contrast, the level of prior creep appeared to have little or no influence on the impulse or amount of energy lost during the impact (Fig. 2E, F), and this suggests cartilage itself plays a minimal role in energy or shock absorption. This finding is consistent with the much earlier postulate of Radin and Paul (1971a) and the whole joint studies of Hoshino and Wallace (1987) that the underlying bone is the main contributor to shock absorption in the joint. Also, there was no obvious association between the level of prior creep and either the number of fissures found per sample or the frequency of AC chip damage (Fig. 7B, C).
    [Show abstract] [Hide abstract] ABSTRACT: This study investigated how varying levels of prior creep deformation in cartilage-on-bone samples influences their mechanical response and vulnerability to structural damage following a single traumatic impact. Bovine patellae were subjected to varying intervals of prior creep loading at a constant stress of 4MPa. Immediately following removal of this stress the samples were impacted with a pendulum indenter system at a fixed energy of 2.2J. With increasing prior creep, the peak force on impact rose, the duration of impact and time to reach peak force both decreased, and both the energy dissipated during impact and the magnitude of impulse were both unchanged by the level of prior creep. With increasing prior creep, the severity of impact-induced osteochondral damage increased: articular cartilage cracks penetrated to a greater depth, extending to the calcified cartilage layer resulting in hairline fractures or articular cartilage delamination and associated secondary damage to the vascular channels in the subchondral bone. The study shows that exposure of the cartilage-on-bone system to prior creep can significantly influence its response to subsequent impact, namely force attenuation and severity of damage to the articular cartilage, calcified cartilage and vascular channel network in the subchondral bone.
    Full-text · Article · Apr 2012
    • These multiple and complex functions require a specialized form. Since the tissue is wedge-shaped, it proves highly adept at stabilizing the curved femoral condyle during articulation with the flat tibial plateau [17, 34, 35]. During everyday activity, axial tibiofemoral forces compress the menisci.
    [Show abstract] [Hide abstract] ABSTRACT: Extensive scientific investigations in recent decades have established the anatomical, biomechanical, and functional importance that the meniscus holds within the knee joint. As a vital part of the joint, it acts to prevent the deterioration and degeneration of articular cartilage, and the onset and development of osteoarthritis. For this reason, research into meniscus repair has been the recipient of particular interest from the orthopedic and bioengineering communities. Current repair techniques are only effective in treating lesions located in the peripheral vascularized region of the meniscus. Healing lesions found in the inner avascular region, which functions under a highly demanding mechanical environment, is considered to be a significant challenge. An adequate treatment approach has yet to be established, though many attempts have been undertaken. The current primary method for treatment is partial meniscectomy, which commonly results in the progressive development of osteoarthritis. This drawback has shifted research interest toward the fields of biomaterials and bioengineering, where it is hoped that meniscal deterioration can be tackled with the help of tissue engineering. So far, different approaches and strategies have contributed to the in vitro generation of meniscus constructs, which are capable of restoring meniscal lesions to some extent, both functionally as well as anatomically. The selection of the appropriate cell source (autologous, allogeneic, or xenogeneic cells, or stem cells) is undoubtedly regarded as key to successful meniscal tissue engineering. Furthermore, a large variation of scaffolds for tissue engineering have been proposed and produced in experimental and clinical studies, although a few problems with these (e.g., byproducts of degradation, stress shielding) have shifted research interest toward new strategies (e.g., scaffoldless approaches, self-assembly). A large number of different chemical (e.g., TGF-β1, C-ABC) and mechanical stimuli (e.g., direct compression, hydrostatic pressure) have also been investigated, both in terms of encouraging functional tissue formation, as well as in differentiating stem cells. Even though the problems accompanying meniscus tissue engineering research are considerable, we are undoubtedly in the dawn of a new era, whereby recent advances in biology, engineering, and medicine are leading to the successful treatment of meniscal lesions.
    Full-text · Article · Oct 2011
    • Subchondral bone is the thin layer of cortical bone immediately deep to the articular cartilage in synovial joints. Subchondral bone serves to transmit and distribute forces from the joint surface to the underlying trabecular bone, and it may serve to dissipate a small portion of the force as well (Hoshino and Wallace 1987; Radin and Paul 1971; Radin et al. 1970; Simon et al. 1972). Increasing subchondral bone density can alter the material properties of this tissue conferring increased compressive strength, compressive modulus, fatigue life, and resistance to crack initiation (Carter and Hayes 1977; Currey 1988 Currey , 2002 Rice et al. 1988; Wall et al. 1979; Wright and Hayes 1977).
    [Show abstract] [Hide abstract] ABSTRACT: We analyze patterns of subchondral bone apparent density in the distal femur of extant primates to reconstruct differences in knee posture, discriminate among extant species with different locomotor preferences, and investigate the knee postures used by subfossil lemur species Hadropithecus stenognathus and Pachylemur insignis. We obtained computed tomographic scans for 164 femora belonging to 39 primate species. We grouped species by locomotor preference into knuckle-walking, arboreal quadruped, terrestrial quadruped, quadrupedal leaper, suspensory and vertical clinging, and leaping categories. We reconstructed knee posture using an experimentally validated procedure of determining the anterior extent of the region of maximal subchondral bone apparent density on a median slice through the medial femoral condyle. We compared subchondral apparent density magnitudes between subfossil and extant specimens to ensure that fossils did not display substantial mineralization or degradation. Subfossil and extant specimens were found to have similar magnitudes of subchondral apparent density, thereby permitting comparisons of the density patterns. We observed significant differences in the position of maximum subchondral apparent density between leaping and nonleaping extant primates, with leaping primates appearing to use much more flexed knee postures than nonleaping species. The anterior placement of the regions of maximum subchondral bone apparent density in the subfossil specimens of Hadropithecus and Pachylemur suggests that both species differed from leaping primates and included in their broad range of knee postures rather extended postures. For Hadropithecus, this result is consistent with other evidence for terrestrial locomotion. Pachylemur, reconstructed on the basis of other evidence as a committed arboreal quadruped, likely employed extended knee postures in other activities such as hindlimb suspension, in addition to occasional terrestrial locomotion.
    Full-text · Article · Apr 2010
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