Samina Anjum, Liaqat Ali Minhas, Azhar Mubarik.
Effects of free mobility verses restricted mobility on the degenerative changes induced by immobilization on the femoral articular cartilage of Rabbit knee.
Pak Armed Forces Med J Jan ;58(2):189-96.

Objective: To produce degenerative changes by immobilization of rabbit Stifle (knee) joint in extension and then to see the subsequent effects of either free or restricted mobility on the femoral articular cartilage. Design: An experimental study. Place and Duration of Study: This study was conducted from April 2006 to April 2007 at Army Medical College, Rawalpindi and National Institute of Health Sciences, Islamabad. Materials and Methods: In this study forty adult New Zealand white rabbits were divided into five groups. Groups I & II served as control and were euthanized at 4 and 8 weeks respectively. The left knee joints of the three study groups (III, IV and V) were immobilized in extension by plaster of Paris cast for 4 weeks. After the removal of cast free (IV) and restricted mobility (V) groups were remobilized for another 4 weeks. Following euthanasia, femoral articular cartilages were dissected and examined both macroscopically and microscopically. To evaluate the degenerative changes thickness of articular cartilage, chondrocytes number and semi quantitative Mankin`s scoring was done. Results: Immobilization in extension for four weeks produced significant degenerative changes that were evident on both gross and microscopic analysis. Animals in free mobility group showed surface irregularities, superficial ulceration, fibrillation and deep clefts reaching radial zone along with reduction in the staining of matrix. Restricted mobility group when compared with the free mobility group showed significant decrease in Mankin`s score and also significant increase in cellularity. The thickness of the articular cartilage in restricted mobility group was although greater than free mobility group but statistically significant difference was not found (p value=.055). Most peculiar feature of restricted mobility group was proliferation of chondrocytes with formation of clones and intense metachromasia around the clones, a tendency towards intrinsic repair. Conclusion: Early motion and free mobility exposed the injured articular cartilage to increased loads when normal activity was allowed. Moreover rest and restricted mobility for 4 weeks following immobilization allowed some restoration of structure of articular cartilage.

PakMediNet -Pakistan's largest Database of Pakistani Medical Journals - http://www.pakmedinet.com