Articular cartilage and bone changes following treatment of focal osteochondral defects in the femoral head with polyether ether ketone implants versus cobalt chromium molybdenum alloy implants: assessment in a goat model
Abstract Objective : This study aimed to investigate the feasibility of applying defect-size polyether ether ketone (PEEK) implant for the treatment of localized osteochondral defects in the femoral head and compared it with cobalt chromium molybdenum (CoCrMo) alloy implant. Methods : A femoral head osteochondral defect model was created in the left hips of goats (n=12). Defects were randomly treated by immediate placement of a PEEK (n=6) or CoCrMo implant (n=6). The un-operated right hip joints served as a control. Goats were sacrificed at 12 weeks. The hip joints were evaluated by gross appearance, computed tomography (CT), and magnetic resonance imaging(MRI). Periprosthetic cartilage quality and the opposing cartilage (at the acetabular) quality were analyzed macroscopically and microscopically. Implant osseointegration was measured by micro-CT and histomorphometry. Results : Radiography revealed that all implants had good overall placement, without loosening of the implant. The modified macroscopic articular evaluation score in the PEEK group was lower than that in the CoCrMo group (p<0.05), and the histological score of the periprosthetic and acetabular cartilage in the PEEK group was lower than that in the CoCrMo group (P<0.05). The mean bone-implant contact for PEEK implants was comparable with that for CoCrMo alloy implants at 12 weeks. Conclusions : A PEEK implant for the treatment of local osteochondral defect in the femoral head demonstrated effective fixation and superior in vivo cartilage protection compared with an identical CoCrMo alloy implant.