Superior fixation of machine-made bone pegs over handmade bone pegs.
BACKGROUND
Bone pegs are one of the best devices to treat an intra-articular lesion with fragments because of the pegs' biological characteristics, but the initial strength of the fragment fixation in these cases is unknown. In addition, the relationship between the geometry of bone pegs and the strength of fragment fixation remains unknown. We hypothesized that a microscopically fine bone peg made by a precision machine can provide a higher level of strength than that of a macroscopically fine bone peg made by hand both initially and postoperatively.


METHODS
The machine-made bone pegs were made from cortical bone of cattle by a precision machine, and the handmade bone pegs were made by hand using the same material. An osteochondral lesion model was made, and two pegs of the same type were inserted to fix each test fragment. The shearing and pull-out strength of the fragment were investigated in both types of peg. Next, both types of peg were inserted into a hole made in the distal femur of a rabbit, and 10 days later, mechanical tests were performed.


RESULTS
The machine-made bone pegs were initially twice as strong as the handmade bone pegs, and they were 1.4 times as strong as the handmade bone pegs at 10 days after surgery.


CONCLUSIONS
We recommend that bone pegs be made by machining rather than by hand. The machine-made bone pegs have the potential to ensure early postoperative rehabilitation.
Department of Orthopaedic Surgery, Faculty of Medicine, Shimane University School of Medicine, Izumo, Shimane, Japan. imades@med.shimane-u.ac.jp
Shinji
S
Imade
Yuji
Y
Uchio
Nobuaki
N
Ozoe
D000818:Animals; D001705:Bioprosthesis; D001858:Bone Nails; D005592:Fracture Fixation / Q000295:instrumentation*; D011474:Prosthesis Design / Q000379:methods*; D011817:Rabbits