Use of a new model allowing controlled uniaxial loading to evaluate tendon healing in a bone tunnel.
The optimal mechanical loading regimen for the healing of a tendon graft in a bone tunnel is unknown. We developed a rat model that directly tensions a healing tendon graft, without the use of confounding joint motion. Fifty cycles of either 0, 3, or 6 N of tension were applied to groups daily for 3 or 6 weeks. At 3 weeks the low load (3 N) group had the highest failure load (p = 0.009), but by 6 weeks there were no differences in failure load among groups. At 3 weeks the high load (6 N) group had greater osteoclast activity compared to the immobilized (0 N) group (p < 0.05), and by 6 weeks there were significantly more osteoclasts in the high load group compared to the low load group (p = 0.01). Bone volume fraction was higher in the immobilized group compared to the 3 N load group at 3 weeks (p = 0.014) and 6 weeks (p = 0.007). At 6 weeks, the immobilized group had greater trabecular number compared to both loading groups (p < 0.05). In conclusion, low magnitude loading had a beneficial early effect but continued loading led to poorer new bone formation over time and no beneficial effect at 6 weeks, perhaps due to delayed maturation from cumulative loads. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:852-859, 2016.
The Hospital for Special Surgery, New York, New York.
Scott A
SA
Rodeo
Department of Orthopaedic Surgery, Lenox Hill Hospital, New York.
Clifford
C
Voigt
Department of Orthopaedic Surgery, University of Missouri, Columbia, Missouri.
Richard
R
Ma
Triangle Orthopaedic Associates, Raleigh, North Carolina.
John
J
Solic
Department of Biomedical Engineering, The City College of New York, New York.
Mark
M
Stasiak
Institute of Sports Medicine, Peking University Third Hospital, Beijing, China.
Xiaodong
X
Ju
Department of Orthopaedic Surgery, Southern Illinois University School of Medicine, Springfield, Illinois.
Saddiq
S
El-Amin
The Hospital for Special Surgery, New York, New York.
Xiang-Hua
XH
Deng
D000818:Animals; D050376:Bone-Patellar Tendon-Bone Grafting; D007103:Immobilization; D008297:Male; D023421:Models, Animal; D011897:Random Allocation; D017207:Rats, Sprague-Dawley; D012038:Regeneration; D013710:Tendons / Q000473:pathology / Q000502:physiology*; D016474:Weight-Bearing; D055114:X-Ray Microtomography
bone ingrowth; bone tunnel; osteoclasts; tendon healing; tensile load