Objective. To evaluate medial radial displacement (MRD) of the medial meniscus in osteoarthritic (OA) and normal knees, with and without weight bearing, using ultrasonography (US), and to prospectively evaluate the time course of changes in MRD in OA knees.Methods. The study subjects were 78 patients with OA of the knee (69% female; mean age 66.4 years) and 20 healthy, asymptomatic subjects (70% female; mean age 64.5 years) who served as a control group. The OA stage was determined according to the Kellgren/ Lawrence (K/L) radiographic grading system. US measurement of MRD was performed with subjects in the supine and standing positions. With the exception of subjects who dropped out, 58 OA knees (followup rate 74%) were evaluated at baseline and ϳ1 year later.Results. The medial meniscus was significantly displaced radially by weight bearing in control knees (P < 0.001) and in knees with K/L grades 1-3 OA (P < 0.01 for each comparison). MRD in either the supine or the standing position was not significantly different between the control knees and the K/L grade 1 knees, but significant differences were noted between the control knees and K/L grade 2 or more severe OA knees (P < 0.01 for each comparison). MRD of the medial meniscus had increased significantly on followup in all knees (P < 0.05 for each comparison) excluding K/L grade 4 knees in the standing position.Conclusion. MRD of the medial meniscus increased with weight bearing and during followup. These findings suggest a close association between extraarticular displacement of the medial meniscus and progression of OA.
Objective. To evaluate the relationships among cartilage and subchondral bone before and after the onset of cartilage degeneration in the Hartley guinea pig model of spontaneous osteoarthritis (OA) as compared with those in Weiser-Maple guinea pigs, which do not develop OA.Methods. Mice from each strain were used at ages 2, 3, 5, and 8 months (n ؍ 7 at each time point). The region observed was the medial tibial plateau. Cartilage degeneration was evaluated histologically. Subchondral bone structure was evaluated based on subchondral bone plate thickness and subchondral cancellous bone trabecular parameters calculated from the microfocal computed tomography 3-dimensional reconstruction image. The bone mineral density (BMD) of the subchondral cancellous bone as well as levels of urinary N-telopeptide of type I collagen (NTX) and serum osteocalcin (OC) were measured.Results. In Hartley guinea pigs, the number of chondrocytes in the surface layer started to decrease at 3 months. At 8 months, fibrillation expanded to the radial zone. In Weiser-Maple guinea pigs, no cartilage degeneration was noted even at 8 months. Subchondral bone plate thickness was significantly lower in Hartley guinea pigs than in Weiser-Maple guinea pigs at 2 months. The subchondral bone had a rod-like and convex structure at 2 months in Hartley guinea pigs. BMD was significantly lower in Hartley guinea pigs than in Weiser-Maple guinea pigs at 2 months. The serum OC level was significantly higher in Hartley guinea pigs than in Weiser-Maple guinea pigs at 2 months and 3 months, whereas the urinary NTX level was significantly lower in Hartley guinea pigs at 3 months.Conclusion. Subchondral bone is fragile, and bone formation may be promoted in subchondral bone before the onset of cartilage degeneration in Hartley guinea pigs. Subchondral bone may be involved in the development of OA.Osteoarthritis (OA) is the most prevalent of joint diseases, and its pathology is characterized by the degeneration of articular cartilage, sclerosis of subchondral bone, and osteophyte formation. Localization of the early lesions of OA has not been clarified, but many researchers have focused on articular cartilage (1,2) and have considered that changes in subchondral bone occur subsequent to the degeneration of articular cartilage. However, a low bone mineral density (BMD), particularly in the knee joint with OA (3,4), high bone turnover (5-7), and efficacy of bone resorption inhibitors for OA (8)(9)(10)(11)(12)(13)(14) have recently been reported, suggesting that subchondral bone plays an important role in the pathogenesis of knee OA. Burr (15) reported that microdamage to subchondral bone by mechanical overload was repaired and led to bone sclerosis, by which bone turnover was enhanced and resulted in the deterioration of subchondral bone, suggesting the importance of subchondral bone and bone turnover in the progression of OA. Most of these clinical and experimental studies of subchondral bone were related to OA progression, but there have been fewer studies con...
Cortical bone responses following administration of parathyroid hormone (PTH) were evaluated using a four-point bending device to clarify the relationship between the effect of PTH and mechanical loading. Female Wistar rats, 6-months-old, [corrected] were used. Rats were randomized into three groups (n = 10/group), namely PTH-5 (5 microgram PTH/kg body weight), PTH-30 (30 microgram PTH/kg body weight), and PTH-v (vehicle). PTH (human PTH (1-34)) was injected subcutaneously three times/week for 3 weeks. Loads on the right tibia were applied in vivo at 29.1 +/- 0.3 N for 36 cycles at 2 Hz 3 days/week for 3 weeks using four-point bending. The administration of PTH and tibial mechanical loading were performed on the same day. After calcein double labeling, rats were killed and tibial cross-sections were prepared from the region with maximal bending at the central diaphysis. Histomorphometry was performed over the entire periosteal and endocortical surfaces of the tibiae, dividing the periosteum into lateral and medial surfaces. The in vivo average peak tibial strains (predicted) on the lateral periosteal surface were 1392.4, 1421.8 and 1384.7 (mu)strain in PTH-v, PTH-5 and PTH-30 groups, respectively, showing no significant difference among the three groups. Significant loading-related increases in the bone formation surface, mineral apposition rate, and bone formation rate were observed at the periosteal and endocortical surfaces. Significant differences between PTH groups were also seen. Interaction between mechanical loading and PTH was significant at both periosteal and endocortical surfaces. It is concluded that PTH has a synergistic effect on the cortical bone response to mechanical loading.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.