Stress shielding of patellar tendon: effect on small-diameter collagen fibrils in a rabbit model.
The purpose of this study was to assess the effects of stress shielding on the microstructure and ultrastructure of the patellar tendon using 40 mature female Japanese white rabbits. The patellar tendon was completely released from stress by drawing the patella toward the tibial tubercle with a stainless steel wire installed between them. Microstructurally, stress shielding for 3 and 6 weeks increased the number of cells approximately fivefold, to that of the control tendon. Collagen bundles were less well oriented in the stress-shielded tendon than in the control. Ultrastructurally, small collagen fibrils with a diameter of less than 90 nm increased in the stress-shielded tendon. The median collagen fibril diameter in 6-week stress-shielded tendon was significantly smaller ( P << 0.05) than in the control tendon (58.8% of control). The ratio of the total area of collagen fibrils to the whole visualized area in the stress-shielded patellar tendon was significantly smaller at 3 and 6 weeks than that in the control. This study demonstrated that complete stress shielding significantly affects the microstructure and ultrastructure of the patellar tendon
Majima
Tokifumi
T
Department of Orthopaedic Surgery, Hokkaido University School of Medicine, N-15, W-7, Kita-ku, Sapporo 060-8631, Japan.
Yasuda
Kazunori
K
Tsuchida
Takamasa
T
Tanaka
Kunio
K
Miyakawa
Kiyoshi
K
Minami
Akio
A
Hayashi
Kozaburo
K
D000704:Analysis of Variance; D000818:Animals; D001707:Biopsy, Needle; D003094:Collagen / Q000502:physiology / Q000648:ultrastructure*; D004195:Disease Models, Animal; D005260:Female; D007150:Immunohistochemistry; D007719:Knee Joint; D017847:Patellar Ligament / Q000473:pathology / Q000648:ultrastructure; D011336:Probability; D011817:Rabbits; D011897:Random Allocation; D013314:Stress, Mechanical; D013710:Tendons / Q000502:physiology* / Q000648:ultrastructure*; D013718:Tensile Strength
D003094:Collagen