Interleukin-6 serum concentration in the elderly undergoing total knee arthroplasty: A potential predictor of the early postoperative knee joint range of motion.

PURPOSE

To analyze the relevance between serum IL-6 with the early postoperative (post-op) knee joint range of motion (ROM) in the elderly undergoing total knee arthroplasty (TKA). To evaluate the factors affecting early post-op knee joint ROM in the elderly after TKA.

METHODS

One hundred and forty-three patients undergoing TKA were included. The patients' general data, perioperative knee joint ROM and serum IL-6, pre-op HSS, WOMAC, SF-36 scores and Wells scores were collected. Repeated data variance analyses were performed to analyze the relevance between serum IL-6 with post-op knee joint ROM. Correlative regression and regression analysis were performed to evaluate the multiple factors affecting knee joint ROM in the elderly undergoing TKA.

RESULTS

The 2-week-post-op (2w-post-op) knee joint ROM was significantly higher in the low IL-6 serum concentration group (< 46.45 ng/L) than in the high group (⩾ 46.45 ng/L) (97.78 ± 7.44∘VS 91.85 ± 7.42∘, F= 16.860, P= 0.000). A significant negative correlation was found between 1d-post-op serum IL-6 concentration with 2w-post-op knee joint ROM (R=-0.513, P= 0.000). The factors influencing the 2w-post-op knee joint ROM included pre-op HSS scores, pre-op WOMAC scores and whether to retain PCL (posterior cruciate ligament) (R2= 0.451, P= 0.009).

CONCLUSION

A higher 1d-post-op IL-6 serum concentration indicated a lower knee joint ROM in the elderly two weeks after TKA.