Abstract
Cementless total hip arthroplasty is one surgical procedure now being established as a treatment method of coxarthrosis: however, this method has various problems. This study assessed whether inflammatory cytokines are useful as a screening parameter of osteolysis since inflammatory cytokines are assumed to be related to the onset of osteolysis. Plain orbital radiography and peripheral blood inflammatory cytokine levels were compared among outpatients in our hospital who had THA at least 5 years prior. Regarding inflammatory cytokines, four factors were evaluated: IL-1, IL-6, TNF-α, and GM-CSF. Moreover, the presence of osteolysis was determined based on the en face view of plain orbital radiography. Of 50 subjects treated with cementless THA, one infected subject was excluded from the assessment and used as a reference; the remaining 49 subjects were assessed. The site of osteolysis was determined from the en face radiographic view; cases were classified according to Gruen's zone classification. Osteolysis in the area of acetabular side was most often observed in Zone II, and the osteolysis in the area of stem was most in Zone 2. No subjects showed elevated IL-I and GM-CSF. Increased TNF-α was observed in 3 subjects, all of them had osteolysis. IL-6 was significantly increased in the subjects with osteolysis. No definitive correlation of increased cytokine was observed regarding the amount of wire abrasion and the annual mean amount of wire abrasion. The results show that a significant increase of serum cytokines was observed in the subjects with osteolysis. However, the increase of wire abrasion amount and annual mean wire abrasion amount did not correlate with an increase of serum cytokine. The results suggest that the response to cytokine is not enhanced by increase of abrasion powder but depends on the amount of abrasion powder penetrated into the space between the bone and the implant. The site of osteolysis was concentrated in Zone II at the screw and the surrounding area of the screw hole on the acetabular side. On the stem side osteolysis was concentrated in the proximal area relatively near to the articular surface. An increase of cytokine does not necessarily develop into os-teolysis. Osteolysis is the result of the balance between osteoclast stimulated and activated by an increase of cy-tokines and the original level of osteoblast. Therefore, osteolysis might be greatly controlled by biological back-ground. In conclusion, IL-6 and TNF-α are useful indicators when diagnosing osteolysis although complete clinical information and plain orbital radiographic assessment are most important.
