C-REACTIVE PROTEIN LEVEL AFTER TOTAL KNEE ARTHROPLASTY IN INDIAN POPULATION: DOES IT FOLLOW ANGLO-SAXON TREND?

INTRODUCTION

This study is to determine the response of CRP after TKR surgery, both unilateral and simultaneous bilateral TKR. According to the previously published literature from North America and Europe CRP value peaks on the 1^st and 2^nd post-operative day and then gradually comes down to normal by 6–8 weeks post-operatively.

AIM

To determine the trend of CRP in Indian patients undergoing TKR, both unilateral and simultaneous bilateral TKR. To see whether it follows the trend in North American and European population and to determine whether there is a difference in the CPR pattern in unilateral versus simultaneous bilateral TKR patients.

MATERIAL & METHODS

Twenty six patients were included in this study. 13 patients each had unilateral TKR and simultaneous bilateral TKR. All the patients were operated by a single surgeon and assistant. Patients who had Rheumatoid arthritis and post operative adverse events like urinary tract infection were excluded from this study. All 26 patients were female patients and the mean age in the unilateral group was 67 years and in the simultaneous bilateral TKR group was 73 years. CRP levels were measured pre- operatively on 2^nd day and 8 weeks.

TKR was performed in a standard fashion. Both the groups received standard pre and post operative antibiotic prophylaxis. All patients received a posterior stabilized knee implant (Maxx Freedom Knee).

RESULTS

In both the groups CRP level shot up on the 2^nd post-operative day. Although the rise in CRP level was significantly higher in the simultaneous bilateral TKR group as against the unilateral TKR group. This difference was statistically significant. The CRP level came back to normal in about 39% of unilateral TKR patients at 8 weeks post operatively, while in majority (12 out of 13) of bilateral simultaneous TKR patient it was still elevated at 8 weeks post-op and had not come to normal.

DISCUSSION

Macrophages are the important in the development of acute phase response namely CRP. The macrophages are present in the bone and bone marrow and less often in the skeletal muscle. The bone and bone marrow injury happening while performing TKR is responsible for elevation of CRP. Various North-American and European studies have shown that the CRP level increases significantly on the 1^st postoperative day and the decreases from a peak on the 2^nd postoperative day, attaining normal value at 6 to 8 weeks after operation. The result of our study are in variance to this published literature.

Nearly 39% of our unilateral TKR patients and majority all of our simultaneous bilateral TKR patients did not achieve a normal CRP at 8 weeks after operation. These findings are significant as CRP is often used as a very sensitive indicator of post operative joint infection. Hence we conclude that the Indian TKR patients take longer time for the CRP values to become normal and the published literature regarding the normal levels of CRP in Unilateral TKR should not be extrapolated to simultaneous bilateral TKR group.