Meniscal movement. An in-vivo study using dynamic MRI.
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We present the first study in vivo of meniscal movement in normal knees under load. Using an open MR scanner, allowing imaging in physiological positions in near to real-time, 16 young footballers were scanned moving from full extension to 90 degrees flexion in the sagittal and coronal planes. Excursion of the meniscal horns, radial displacement and meniscal height were measured. On weight-bearing, the anterior horn of the medial meniscus moves through a mean of 7.1 mm and the posterior horn through 3.9 mm, with 3.6 mm of mediolateral radial displacement. The height of the anterior horn increases by 2.6 mm and that of the posterior horn by 2.0 mm. The anterior horn of the lateral meniscus moves 9.5 mm and the posterior horn 5.6 mm, with 3.7 mm of radial displacement. The height of the anterior horn increases by 4.0 mm, and that of the posterior horn by 2.4 mm. In non-weight-bearing, the anterior horn of the medial meniscus moves 5.4 mm and the posterior horn 3.8 mm, with 3.3 mm of radial displacement. The anterior horn of the lateral meniscus moves 6.3 mm, and the posterior horn 4.0 mm, with 3.4 mm of radial displacement. The most significant differences between weight-bearing and non-weight-bearing were the movement and vertical height of the anterior horn of the lateral meniscus. (+info)
WOMAC Osteoarthritis Index--additional dimensions for use in subjects with post-traumatic osteoarthritis of the knee. Western Ontario and MacMaster Universities.
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OBJECTIVE: To compare the sensitivity of WOMAC and the two added dimensions Sport and Recreation Function and Knee Related Quality of Life in subjects with radiographic knee OA to that in controls. To study the influence of age on the reported outcomes. DESIGN: Outcomes were compared between subjects having had meniscectomy 21 years ago and which at time of follow-up had definite radiographic OA (N=41, mean age 57), and age- and sex-matched controls without radiographic OA (N=50, mean age 53). For the purpose of studying the impact of age, the groups were divided in two age groups, younger and older than 50 years, respectively. Close to 50% of both groups reported current physical activity levels of at least recreational golf, dancing, hiking, etc. Symptoms and function were assessed by WOMAC Osteoarthritis Index and the added dimensions Sport and Recreational Function (Sport/Rec) and Knee Related Quality of Life (QOL). A percentage score was calculated, 0 indicating extreme knee problems and 100 indicating no knee problems. RESULTS: The control group had mean scores of 88-98 for the different dimensions. The OA group scored significantly lower in all dimensions (P< 0.0001). The most discriminative dimensions in both age groups were Sport/Rec and QOL with mean scores of 52 and 59 (ranges 0-100). CONCLUSION: The dimensions Sport and Recreation Function, and Knee Related QOL were highly sensitive and discriminant outcomes in both age groups and should be assessed in addition to WOMAC in subjects with post-traumatic osteoarthritis of the knee. (+info)
Biomechanical, histological and immunohistological studies of patellar cartilage in an ovine model of osteoarthritis induced by lateral meniscectomy.
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OBJECTIVE: To evaluate the biomechanical, histological and immunohistochemical changes induced in patellar articular cartilage (AC) in ovine stifle joints 3 months after bilateral lateral meniscectomy, a procedure known to induce experimental osteoarthritis (OA) in the femoro-tibial joint (FTJ). METHODOLOGY: Fifteen mature adult Merino female sheep were used in this study. Ten were subjected to bilateral-lateral meniscectomy, while the remaining five were used as 'non-operated controls' (NOC). All animals were killed 3 months post-surgery. Topographical biomechanical indentation tests were performed on each patellae using a UMIS-2000 micro-indentation system. Initial load, relaxed and unload shear moduli were determined using an elastic analytical model, while the permeability was assessed by comparing the indentation response to a simulated indentation test conducted using a poroelastic finite element model. Immunohistochemical, normal and polarized histological studies were performed on each specimen after biomechanical testing. RESULTS: Patellar AC from meniscectomized joints exhibited an overall decrease in initial (-34%), relaxed (-32%) and unload shear modulus (-22%), and an increase in the permeability (+72%) relative to NOC cartilage (P< 0.01). The most significant differences in mechanical properties occurred on the lateral and central aspects of the patellae. There were no significant histological difference in staining between sections from NOC and meniscectomized joint AC using Toluidine Blue, a dye which binds to proteoglycans. However immunohistochemical staining with monoclonal antibody MAb 3B3(-), a putative marker of early OA change in PGs, demonstrated increased binding in the lateral and central regions of patellar sections from meniscectomized joints relative to the same regions of NOC AC. Moreover polarized light microscopy of Picro Sirius red stained sections revealed a significant decrease in birefringence intensity in the superficial-middle zones of the lateral and central regions of the patellar cartilage derived from the meniscectomized joints. CONCLUSION: This study has demonstrated that lateral meniscectomy is a procedure which was known to induce classical OA like changes in AC and subchondral bone of the FTJ also produced an early pathological response in the patellar AC. (+info)
Evidence of early subchondral bone changes in the meniscectomized guinea pig. A densitometric study using dual-energy X-ray absorptiometry subregional analysis.
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OBJECTIVE: Subchondral bone changes are thought to be an important aetiological element in the pathogenesis of osteoarthritis (OA). To confirm this hypothesis in the meniscectomized (MNX) guinea pig model, bone densitometry was performed in the subchondral bone of the distal femur. METHODS: MNX and sham-operated (SH) guinea pigs were studied 1 and 3 months after partial meniscectomy at the medial side of the left knee. Bone mineral density was measured at the lateral (BMD-L) and medial (BMD-M) sides of the distal femur using dual-energy X-ray absorptiometry (DXA). BMD-M was then compared to the bone volume evaluated by histomorphometry at the medial epiphyseal part of the proximal tibia (BV-M). RESULTS: One month after operation, in MNX animals left femur BMD-M was significantly lower than in the contralateral femur (-9%, P< 0.01) and than in the left femur of SH (-11%, P< 0.01). By contrast, 3 months after meniscectomy BMD-M was higher in the femur than in the contralateral femur (+4%, P< 0.05); BV-M tended to be higher on the left than on the right side (+4%, P< 0.06), and was significantly correlated with BMD-M at the 2 grouped time points: r=0.74 (P< 0.001). CONCLUSIONS: These data emphasize the usefulness of DXA as a simple tool to assess subchondral bone changes at the OA-affected side of the femur and reveal typical variations of bone metabolism in the initiation of OA pathology in the MNX guinea pig: early bone loss at the subchondral level followed by increased bone density. (+info)
Nitric oxide production and apoptosis in cells of the meniscus during experimental osteoarthritis.
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OBJECTIVE: To examine the pathologic changes in meniscus tissue during experimental osteoarthritis (OA) and to determine the relationship between nitric oxide (NO) synthesis, apoptosis, and meniscus degradation. METHODS: OA was induced in rabbits by anterior cruciate ligament (ACL) transection. Knees were harvested after 9 weeks and assessed for OA severity. Menisci were subjected to histologic, immunohistochemical, and electron microscopic analyses for the presence of nitrotyrosine and apoptosis. Menisci were also cultured for analysis of NO production. RESULTS: All menisci from joints with ACL transection demonstrated degenerative changes. A high number of apoptotic cells was present in the medial part of menisci, which contains chondrocytic cells. Menisci from nonoperated contralateral knees contained only small numbers of cells in apoptosis. Conditioned media from meniscus cultures contained similarly elevated levels of nitrite as cartilage cultures from the same arthritic knees. Nitrotyrosine immunoreactivity, an indicator of in vivo NO production, was prominent in menisci from knees with ACL transection. In addition, menisci from normal knees produced high levels of NO in response to in vitro stimulation with interleukin-1beta or lipopolysaccharide. CONCLUSION: These observations suggest that pathologic changes in menisci are a regular feature of experimentally induced OA and are associated with NO production and meniscus cell apoptosis. (+info)
Arthroscopic reconstruction of the anterior cruciate ligament with patellar-tendon autograft and interference screw fixation. The results at seven years.
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Deficiency of the anterior cruciate ligament (ACL) is a common disorder which can lead to changes in lifestyle. We followed 59 patients who had had arthroscopic reconstruction of the ACL using a central-third patellar-tendon autograft for seven years to assess the long-term effectiveness of recent advances in reconstruction of the ACL. The standard criteria for evaluation of the International Knee Documentation Committee, the Lysholm knee score and measurements using the KT 1000 arthrometer all showed satisfactory results. Deterioration in the clinical performance after seven years was associated with osteoarthritic changes and correlated with chronic ligament injuries and meniscectomy. There were three traumatic and three spontaneous ruptures. We believe that the procedure can be successful, but remain concerned about failure of the graft and osteoarthritis. The results raise questions about the best time to operate and suggest that early surgery may reduce the risk of osteoarthritis. (+info)
Meniscal subluxation: association with osteoarthritis and joint space narrowing.
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OBJECTIVE: Since complete meniscectomy leads to knee OA, we investigated the potential links among meniscal subluxation, joint space narrowing and symptomatic OA. MATERIALS AND METHODS: 233 cases with symptomatic knee OA and 58 asymptomatic controls underwent radiography and MR imaging of the knee. Joint space narrowing was measured on weight-bearing PA fluoroscopy-positioned radiographs. The amount of medial or lateral meniscal subluxation was measured on coronal MR images. The prevalence and severity of meniscal subluxation was compared in cases and controls. We evaluated the correlation of the degree of meniscal subluxation with joint space narrowing, Kellgren and Lawrence grade, and two major risk factors for the development of OA, age and weight. RESULTS: Cases had more medial and lateral subluxation than controls. Mean medial meniscal subluxation was 5.1 mm in cases and 2.8 mm in controls (P=0.001). Modest degrees of meniscal subluxation were common in both cases and controls: 81% of cases and 64% of controls had >/=3 mm of subluxation; age and gender adjusted (P=0.006). Severe degrees of subluxation were almost unique to OA cases (e.g. prevalence of >/=7 mm, 35% cases vs. 7% controls, P< 0.001). Among controls, severe degrees of subluxation were present only in those with radiographic joint space narrowing (defined as >/=grade 1 narrowing on a 0-3 scale). In cases, there was a strong correlation between the degree of medial meniscal subluxation and the severity of medial joint space narrowing (r=0.56, P=0.0001). Similar results were present in the lateral compartment. Meniscal subluxation did not correlate with age or weight. CONCLUSION: Meniscal subluxation is highly associated with symptomatic knee OA. In subjects with osteoarthritis, increasing meniscal subluxation on MR correlates with the severity of joint space narrowing. (+info)
Discoid lateral menisci in older patients. A radiographic study of 21 cases.
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Twenty-three knees of 21 patients over 40 years of age with discoid lateral menisci were examined by radiography. The mean age of the patients was 59.7 years (range: 40-78 years). No patient had symptoms before the age of 40 and only 12 knees gave symptoms from the lateral compartment, although tears of a discoid lateral meniscus were diagnosed by arthrography in 21 of the 23 knees. Varus inclination occurred more frequently than valgus inclination. Subchondral bone sclerosis was more common in the medial compartment. However, high incidences of marginal osteophytes in the lateral compartment and morphological anomalies (cupping or flattening) of the lateral tibial plateau were revealed by radiography. (+info)