Extensor mechanism reconstruction after proximal tibial replacement.
We developed an in vivo model of the attachment of a patellar tendon to a metal implant to simulate the reconstruction of an extensor mechanism after replacement of the proximal tibia. In 24 ewes, the patellar tendon was attached to a hydroxyapatite (HA)-coated titanium prosthesis. In 12, the interface was augmented with autograft containing cancellous bone and marrow. In the remaining ewes, the interface was not grafted. Kinematic gait analysis showed nearly normal function of the joint by 12 weeks. Force-plate assessment showed a significant increase in functional weight-bearing in the grafted animals (p = 0.043). The tendon-implant interface showed that without graft, encapsulation of fibrous tissue occurred. With autograft, a developing tendon-bone-HA-implant interface was observed at six weeks and by 12 weeks a layered tendon-fibrocartilage-bone interface was seen which was similar to a direct-type enthesis. With stable mechanical fixation, an appropriate bioactive surface and biological augmentation the development of a functional tendon-implant interface can be achieved.
Oddy
M J
MJ
The Centre for Biomedical Engineering, Institute of Orthopaedics and Musculo-Skeletal Science, University College London, Brockley Hill, Stanmore HA7 4LP, UK.
Pendegrass
C J
CJ
Goodship
A E
AE
Cannon
S R
SR
Briggs
T W R
TW
Blunn
G W
GW
D000818:Animals; D001859:Bone Neoplasms / Q000601:surgery*; D001860:Bone Plates; D016025:Bone Transplantation / Q000379:methods; D005260:Female; D005684:Gait; D006882:Hydroxyapatites; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery*; D010329:Patella / Q000601:surgery; D016059:Range of Motion, Articular; D012756:Sheep; D013710:Tendons / Q000601:surgery; D013977:Tibia / Q000601:surgery*; D014025:Titanium; D016474:Weight-Bearing
D006882:Hydroxyapatites; D014025:Titanium