Cartilage of Knee

Resumen:
Contexto: La osteoartrosis (OA) es una enfermedad degenerativa articular, con asiento primario en el cartílago articular, asociada clínicamente a dolor, impotencia y limitación funcional articular progresiva. Su tratamiento, conlleva la utilización de multiples recursos en salud, entre personas de mediana edad y ancianos. Objetivo: comprobar evidencias de eficacia terapéutica de la viscosuplementacion con Acido Hialurónico Reticulado (Cientific Synovial), como sustituto temporal o complemento del líquido sinovial en las articulaciones con OA.

Knee osteoarthritis is one of the most common musculoskeletal pathologies, and results in severe joint pain, loss of mobility, compromised quality of life, and high medical costs. With no cure other than total joint replacement, and the incidence of osteoarthritis rising worldwide, the need to understand how the disease develops has reached a critical level. The mechanism(s) underlying the initiation and progression of knee osteoarthritis remain unknown despite years of extensive research. Alterations in the spatial loading pattern on the joint’s articular cartilage, for example, due to knee injury, have been hypothesized to trigger the onset of the disease. The theory presupposes that the mechanical properties of knee cartilage are non-uniform such that the underlying cartilage is unable to sustain the new loading pattern and deteriorates. However, this tenet is challenging to test directly because it requires detailed knowledge of spatial mechanical properties of the cartilage, which is currently unknown.
Therefore, this dissertation sought to address current knowledge gaps by mapping the elastic modulus of healthy human knee articular cartilage across the joint surface. This work represented the first such mapping with fine spatial resolution and employing a physiologically relevant compressive strain rate.  Significant variations in modulus were found across the femur and tibial cartilage. Moreover, these variations conformed to a consistent regional pattern across knees, which has not previously been demonstrated.
These findings subsequently motivated the development of a constitutive relation that could successfully simulate spatially dependent, high strain rate mechanics. A transversely isotropic hyperelastic model was developed and compared with isotropic hyperelastic models to determine which constitutive relation best represented the natural cartilage mechanics. The transversely isotropic model replicated the spatial mechanical dependence of the tissue through variations in a single model parameter. The model is mechanistic, has a structure and parameters that are analogous to human cartilage physiology, is computationally efficient, and is straightforward to implement in commercial finite element packages. The transversely isotropic model represents a novel method for implementing the non-uniform mechanics of knee cartilage that are critical to understanding the initiation and progression of knee osteoarthritis. The characterization of regional mechanical properties of human knee cartilage performed herein has contributed essential baseline knowledge that will fundamentally advance experimental and computational studies of knee osteoarthritis development toward widespread prevention of this devastating disease.

The estimation of articular cartilage of knee plays an important role in determining osteoarthritis (OA) level. The purpose of this study is to implement the segmentation, analysis and visualization techniques to characterize the knee cartilage in a simplified way. The segmentation technique used in this work is semi-automatic and based on Bezier splines and Canny edge detection. Cartilage edges are enhanced by using anisotropic diffusion to smooth the images. Shape-based interpolation is performed on the segmented cartilage in a simplified way for getting isotropic voxels. MRI registration is based on an approach which involves artificial matching of points at different slices. Analysis of the cartilage is then carried out by calculating its thickness and volume. Visualization of articular cartilage gives a supplementary tool to characterize it for quantification purpose.

The Anterolateral Ligament (ALL) of the Knee was recently discovered. 
ALL has been considered as a prime stabiliser of the rotational instability of the knee . There is no complete consensus about its anatomy .The purpose of this study is to compare mechanical properties of ALL and IlioTibial Tract (ITT). The specimens were embalmed with a new product. A membranous structure (ALL) cross anterior to the gain of FCL and stretched with combined varus, flexion and internal rotation of the knee. Two tests were carried out for a relaxation test and an elongation test to identifies non-linear behaviour and behaviour at rupture .ITT found to be 6 times more resistant to large strain than that ALL but its damage and its rupture occur at strain 3 and 2 times smaller, respectively. Average Young Modulus for ITT is 225.7 ± 99.4 and for ALL is 38.15 ± 52.98.
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The diagnosis of patellofemoral joint disorders is challenging for orthopaedic surgeons on the account of complicated pathophysiology that underlies them. The origin of patellofemoral symptoms is generally multifactorial, and therefore the clinical examination should take into account the patient as a whole, and meticulous attention must be drawn to the history, morphology and clinical examination to have a definitive diagnosis and address the patient's pathology. It should be remembered that a proper therapeutic approach can only be engineered with a thorough analysis of the patients' disorder.

Objectives Osteochondral injuries, if not treated adequately, often lead to severe osteoarthritis. Possible treatment options include refixation of the fragment or replacement therapies like Pridie drilling, microfracture or osteochondral grafts, all of which have certain disadvantages. Only refixation of the fragment can produce smooth and resilient joint surface. The aim of this study was the evaluation of an ultrasound-activated bioresorbable pin for the refixation of osteochondral fragments under physiological conditions. Methods In 16 Merino sheep, specific osteochondral fragments of the medial femoral condyle were produced and refixed with one of conventional bioresorbable pins, titanium screws or ultrasound-activated pins. Macro-and microscopic scoring was undertaken after three months. Results The healing ratio with ultra-sound activated pins was higher than with conventional pins. No negative heat effect on cartilage has been shown. Conclusion As the material is bioresorbable, no further surgery is required to remove the implant. MRI imaging is not compromised as it is with implanted screws. The use of bioresorbable pins using ultrasound is a promising technology for the refixation of osteochondral fractures.

Objective: The authors developed the autologous fibrin-base scaffold for chondrocytes and bone marrow mesenchymal stem cells (BM-MSCs) implantation and evaluated cells viability in autologous fibrin-base scaffold comparing to commercial fibrin glue. Material and Method: The chondrocytes and BM-MSCs were seeded into autologous fibrin-base scaffold and commercial fibrin glue. The cell viability and proliferation were evaluated at 1 and 7 days. The histology were evaluated with hematoxylin-eosin (H&E) staining and cartilaginous matrices formation with Alcian blue, Saffanin-0, Toluidine blue, and Collagen type II staining at 6 weeks. The fixation of the scaffolds was observed. Results: The chondrocytes and BM-MSCs could not survive in commercial fibrin glue. The chondrocytes and BM-MSCs in autologous fibrin-base scaffold could proliferate and synthesize the cartilaginous matrices on Alcian blue, Saffanin-0, Toluidine blue, and Collagen type II staining at 6 weeks. The fixation strength is excellent. Conclusion: The developed autologous fibrin-base scaffold can be used as the scaffold for chondrocytes and BM-MSCs implantation with potential to implant chondrocytes and BM-MSCs arthroscopically.

Background: With the advent of MRI (Magnetic Resonance Imaging), Synovial lesions around knee are being more and more easily detected. Synovial lesions of knee present with boggy swelling, effusion, pain, and restriction of motion. Differential diagnoses of such lesions include pigmented villonodular synovitis, synovial lipoma, synovial chondromatosis, rheumatoid arthritis, synovial hemangioma, amyloid arthropathy, xanthomata and lipoma arborescens. CT and MRI often help in diagnosis of such lesions. MRI of Lipoma Arborescens has been regarded to have characteristic diagnostic appearanceit includes a synovial mass with frond-like architecture and fat signal intensity on all pulse sequences. Sometimes Lipoma Arborescens can present in conjunction with inflammatory arthritis. Synovectomy is often curative for such conditions. Findings: We report two cases where lesions diagnosed as Lipoma Arborescens on MRI subsequently revealed to be chronic inflammatory synovitis, characterized by absence of fat infiltration in histopathological examinationrefuting the original diagnosis. There was infiltration of lymphocytes and neutrophils in the synovium, suggestive of chronic inflammatory arthritis. Both of these patients required management from rheumatologist, and had relief of symptoms after use of methotrexate and hydroxychloroquine. We also report a third case, where a loose body appearing as chondral fragment on arthroscopy was subsequently diagnosed as an organized hematoma on histopathological examination. Conclusion: Diagnostic pitfalls after MRI of the knee is not uncommon. For example-normal variant of meniscomeniscal ligaments have been reported as meniscal tears; motion artifacts have been falsely reported as meniscal injuries; and meniscofemoral ligament can appear as free osteochondral fragment. In most of these cases, a routine arthroscopy is enough to clear the confusion. However, as evident in the three cases described herein some synovial lesions of knee joint, even after MRI and arthroscopic examination, histopathological confirmation may still be prudent. In spite of availability of advanced imaging technologies and high definition arthroscopy equipment, an arthroscopy surgeon still must not forget the value of histopathological examination in establishing the true nature of synovial lesions of the knee joint.

The pathological changes in osteoarthritis-a degenerative joint disease prevalent among older people-start at the molecular scale and spread to the higher levels of the architecture of articular cartilage to cause progressive and irreversible structural and functional damage. At present, there are no treatments to cure or attenuate the degradation of cartilage. Early detection and the ability to monitor the progression of osteoarthritis are therefore important for developing effective therapies. Here, we show that indentation-type atomic force microscopy can monitor age-related morphological and biomechanical changes in the hips of normal and osteoarthritic mice. Early damage in the cartilage of osteoarthritic patients undergoing hip or knee replacements could similarly be detected using this method. Changes due to aging and osteoarthritis are clearly depicted at the nanometre scale well before morphological changes can be observed using current diagnostic methods. Indentation-type atomic force microscopy may potentially be developed into a minimally invasive arthroscopic tool to diagnose the early onset of osteoarthritis in situ.

Cartilage matrix is a composite of discrete, but interacting suprastructures, i.e. cartilage fibers with microfibrillar or network-like aggregates and penetrating extrafibrillar proteoglycan matrix. The biomechanical function of the proteoglycan matrix and the collagen fibers are to absorb compressive and tensional loads, respectively. Here, we are focusing on the suprastructural organization of collagen fibrils and the degradation process of their hierarchical organized fiber architecture studied at high resolution at the authentic location within cartilage. We present electron micrographs of the collagenous cores of such fibers obtained by an improved protocol for scanning electron microscopy (SEM). Articular cartilages are permeated by small prototypic fibrils with a homogeneous diameter of 18 ± 5 nm that can align in their D-periodic pattern and merge into larger fibers by lateral association. Interestingly, these fibers have tissue-specific organizations in cartilage. They are twisted ropes in superficial regions of knee joints or assemble into parallel aligned cable-like structures in deeper regions of knee joint-or throughout hip joints articular cartilage. These novel observations contribute to an improved understanding of collagen fiber biogenesis, function, and homeostasis in hyaline cartilage.

Objective. Subchondral bone and the osteochondral junction are thought to contribute to osteoarthritis (OA) knee pain. We undertook this study to identify osteochondral pathologies specifically associated with symptomatic human knee OA. Methods. Medial tibial plateau samples from 2 groups of subjects (n = 31 per group) were matched for macro-scopic chondropathy scores. The symptomatic chondropathy group had undergone total knee replacement for OA knee pain, at which time specimens of the medial tibial plateau were obtained. The asymptomatic chondropathy group included subjects who died of unrelated illness (specimens were obtained at postmortem examination) and who had not previously sought help for knee pain. OA histopathology, immunoreactivity for nerve growth factor (NGF) and CD68 (macrophages), tartrate-resistant acid phosphatase-positive subchondral osteoclasts, and synovitis were compared between groups. Results. Mankin scores, subchondral bone density, and subchondral CD68-immunoreactive macrophage infiltration were similar between the 2 groups. NGF-like immunoreactivity was found in subchondral mononuclear cells and osteoclasts, as well as in chondrocytes. NGF in osteochondral channels and osteoclast densities in subchondral bone were higher in the symptomatic chondropathy group than in the asymptomatic chondropathy group (P < 0.01 and P = 0.02, respectively), as were synovitis scores (P < 0.01). Osteochondral pathology was not significantly associated with synovitis score. The differences in NGF expression and in osteoclast density remained significant after adjustment for age and synovitis score (P = 0.01 and P = 0.04, respectively). Osteochondral NGF and osteoclast densities , together with synovitis scores, explained ~28% of sample allocation to symptomatic or asymptomatic groups. Conclusion. Subchondral pathology was associated with symptomatic knee OA, independent of chondropathy and synovitis. Increased NGF expression in osteochondral channels and increased osteoclast density appear to be key features associated with bone pain in knee OA.

Background: Total knee arthroplasty (TKA) is one of the most effective surgical interventions for pain relief and functional recovery in young patients with rheumatoid arthritis, ankylosing spondylitis, traumatic arthritis, osteoarthritis knee, hampering the daily activities in life. The encouraging TKA results have prompted a growth in TKA utilisation, particularly in younger patients and a move away from procedures such as osteotomy and UKA which have been associated with higher re-operation rates. Over the last 2 decades there has been an increasing tendency toward the use of TKA in young adults, with some countries reporting a 5-fold increase in the last 10 years. Material and Method: This study was done on the patients who underwent total knee arthroplasty (37) at MGM medical college and hospital, Kamothe, Navi Mumbai. Out of 37 patients, 6 patients did not followed up at regular interval. Only 31 patients were included in the study (18 females and 13 males) fulfilling the inclusion and exclusion criteria. Total 50 knee were included in this study. Results: This study includes 31 cases fulfilling the inclusion and exclusion criteria with total 50 knees undergoing TKA. The mean age was 46.5 years. The functional outcome was calculated using knee society score. The average knee society score was 70.5 after 6 month post TKA while it was 80.5 after 1 year with reduced pain upto 6 month and almost no pain after 1 year. Three patients were seen with MRSA positive results and were operated after been treated with mupirocin. Two patients showed superficial skin infection following TKA. Conclusions: The total knee arthroplasty is one of the most successful and patient satisfactory surgical procedure in young patients relieving pain and daily activities in life as compared to old age patients undergoing TKA. In our study we have seen that it had provided the stability and promising result, by providing back the ability to carried out daily activities by own self after undergoing TKA in young patients who were facing problems in carrying out their daily activities by providing good outcomes as measured by knee society score as compared to older patients undergoing TKA.