Healing of subcapital femoral osteotomies fixed with self-reinforced poly-L-lactide screws: an experimental long-term study in sheep.
Subcapital femoral osteotomies of ten young adult sheep were fixed with two bioabsorbable, self-reinforced, poly- L-lactide (SR-PLLA) lag screws of 4.5 mm in diameter. At 3 weeks radiographs were taken to check the reduction and fixation achieved. After follow-up periods of 12 weeks, 1 year and 3 years with three sheep in each group, and of 7 years and 4 months with one sheep, the sheep were killed, and the healing of the osteotomies, degradation and tissue response of the implants were examined radiographically, histologically and microradiographically. All osteotomies healed with a firm bony union. There was no dislocation or wound infection. Histologically, there was no marked tissue response in the bone tissue. At 12 weeks the implants were grossly intact, at 1 year granulation tissue and new bone formation had started to penetrate into the implant, and at 3 years the implant area was mostly replaced by connective tissue and new bone, but implant material was still seen as little islands surrounded by some lymphocytes. At 7 years and 4 months, the implant material had been degraded and replaced by tight bone. Self-reinforced poly- L-lactide lag screws seem to possess adequate mechanical properties and good biocompatibility for this demanding fixation.
Department of Orthopaedics and Traumatology, Helsinki University Central Hospital, PO Box 266 (Topeliuksenkatu 5), 00029 HUS, Helsinki, Finland. partio@kolumbus.fi
Kirsi
K
Jukkala-Partio
Outi
O
Laitinen
Jarkko
J
Vasenius
Esa K
EK
Partio
Terttu
T
Toivonen
Pekka
P
Tervahartiala
Jaakko
J
Kinnunen
Pentti
P
Rokkanen
D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials; D015519:Bone Density / Q000502:physiology; D001863:Bone Screws; D005269:Femur / Q000000981:diagnostic imaging / Q000502:physiology* / Q000601:surgery*; D008422:Materials Testing; D010027:Osteotomy / Q000295:instrumentation* / Q000379:methods; D011091:Polyesters / Q000737:chemistry; D011859:Radiography; D012756:Sheep; D014945:Wound Healing / Q000502:physiology*
D001672:Biocompatible Materials; D011091:Polyesters