Inflammatory Involvement in Rabbit Knee following Immobilization and Resulting in Osteoarthritis

Abstract

The inflammatory involvement of the synovium in immobilization-induced experimental osteoarthritis in rabbit knees has been investigated. One knee of each of 33 rabbits was immobilized for up to 5 weeks in extension and then allowed to remobilize for up to 8 weeks. Histological examination revealed the presence of marked inflammatory changes in the synovium which were evident after 4 days of immobilization. These were characterized by a rapid proliferation of synovial lining cells followed by mononuclear cell infiltration and fibrosis. The synovial cell proliferation decreased during the latter part of the immobilization period but reappeared in a more severe form during remobilization, at which time gross changes could be demonstrated in the joints. Synovial fluid levels of the lysosomal enzyme N-acetyl-beta-D-glucosaminidase were elevated on day 3 and day 10 but had returned to baseline levels by day 24 of immobilization. Treatment of the animals with the nonsteroidal anti-inflammatory agent flurbiprofen (10 mg/kg/day) had neither a beneficial nor a deleterious effect on any of the parameters measured. This study has shown that immobilization-induced experimental osteoarthritis in rabbits is associated with a marked inflammatory component and that during the remobilization phase of this model the inflammation appears to be a secondary event.

New rabbit knee model of posttraumatic joint contracture: Indirect capsular damage induces a severe contracture

“…7,[13][14][15][16][17] Most nontraumatic models result in contractures which reverse to almost normal after remobilization. 12,[18][19][20] The combination of immobilization and trauma has been shown to promote a more permanent loss of motion.…”

Expression of type I collagen in the capsule of a contracture knee in a rat model

“…A large number of experimental studies on joint immobilization have been reported [6][7][8][9][10][11][12]. However, phenomena occurred in a joint cavity after joint immobilization have not been agreed in opinion.…”

Physiologie der Entstehung von Gelenkkontrakturen

“…Wie Reyher [31] beobachtete auch er keine Gelenkentzündungen durch Immobilisation, die allerdings ab und zu durch gelenknah gelegene Frakturen auftreten könnten [26]. Müller (1924) [25] beobachteten eine Hyperplasie der Synovia, deren Fältelung (Villi) und Pannusbildung kurz nach Beginn der 5-wöchigen Schienenimmobilisation zunahmen, dann abfielen und mit der Remobilisation wieder deutlich anstiegen. In der infra-und suprapatellaren Synovia zeigten sich schon nach 4 Tagen Entzündungszeichen, die nach 10 Tagen anstiegen, anschließend leicht abfielen und mit der Remobilisation erneut über das Immobilisationsniveau zunahmen.…”

“…In der infra-und suprapatellaren Synovia zeigten sich schon nach 4 Tagen Entzündungszeichen, die nach 10 Tagen anstiegen, anschließend leicht abfielen und mit der Remobilisation erneut über das Immobilisationsniveau zunahmen. Die Autoren konnten 3 -17 Tage nach Immobilisationsbeginn keinen erhöhten Gehalt an Prostaglandinen in der Synovialflüssigkeit finden [25].…”

“…Michelsson und Hunneyball [25] stellten 4 Tage nach Immobilisationsbeginn einen progressiven Abfall des Proteoglykangehalts fest, nicht hingegen der kollagenen Fasern während der 5-wöchi-gen Schienenimmobilisation.…”