Serum C-Reactive Protein Distribution in Minimally Invasive Total Knee Arthroplasty Do Not Differ with Distribution in Conventional Total Knee Arthroplasty

Minimally invasive total knee arthroplasty (MITKA) has been developed to reduce surgical trauma and facilitate rehabilitation after arthroplasty. A plausible hypothesis is that this reduced trauma results in lower concentrations of circulating inflammatory biomarkers, such as C-reactive protein (CRP). In this study, we compared CRP concentrations in patients undergoing MITKA to those undergoing conventional TKA (CTKA). Eight hundred and seven patients undergoing MITKA were prospectively recruited. CRP was measured before operation and on days 2, 4, 21, and 42 after operation. Two hundred and forty-seven patients who had CTKA were collected retrospectively, with the same inclusion and exclusion criteria as those who had MITKA. We found in both groups, that CRP values rose abruptly after operation, with peak values reached on day 2 or 4. Values then declined so that by days 21 and 42 they were only modestly above baseline values. Throughout the entire study period, mean CRP in MITKA patients did not differ significantly from those in CTKA patients. However, a significantly higher proportion of CTKA patients than of MITKA patients had peak CRP values at day 4 rather than at day 2 (76.8% vs 42.5%), a difference that was more pronounced in women. Also, by day 42, CRP values were still above baseline in 18.5% of MITKA patients and 28.8% of CTKA patients without known complications. In conclusion, CRP distribution pattern was similar in patients who received MITKA or CTKA,. CRP values remained slightly elevated in both MITKA and CTKA patients for as long 42 days after operation. These findings suggest that MITKA is no less traumatic than CTKA, as determined by CRP values, and the patterns of postoperative CRP may be useful in the management of TKA patients.