Postoperative kinetics of point-of-care C-reactive protein versus total white blood cell count after tibial plateau leveling osteotomy in dogs

Background and Aim: Objective assessment of the postoperative acute phase response following major orthopedic surgery, such as tibial plateau leveling osteotomy (TPLO), is essential for distinguishing uncomplicated recovery from infectious complications. Serum C-reactive protein (CRP) levels typically return to baseline by 14 days postoperatively, whereas total white blood cell (WBC) counts may remain nonspecifically elevated due to physiological stress. This study aimed to prospectively characterize and directly compare the postoperative kinetics of point-of-care CRP and total WBC counts in dogs undergoing TPLO.

Materials and Methods: Thirteen client-owned dogs undergoing standardized TPLO (classified as Level 4 severity) were prospectively enrolled. Venous blood samples were collected preoperatively (Day 0) and on postoperative days 1, 3, 5, 7, 10, and 14. Serum CRP concentrations were measured using a validated point-of-care immunofluorescence assay (SmartDiag®), and total WBC counts were determined concurrently using an automated hematology analyzer. Temporal changes in both biomarkers were analyzed using a repeated-measures one-way analysis of variance with Dunnett’s post hoc test.

Results: Both biomarkers increased significantly from baseline and peaked on postoperative day 1 (p < 0.05). However, their subsequent kinetics diverged markedly. Mean serum CRP concentrations showed a rapid and progressive decline, approaching preoperative baseline levels by postoperative day 7 and remaining stable thereafter. In contrast, mean total WBC counts remained significantly elevated above baseline throughout the entire 14-day monitoring period without returning to preoperative values. A moderate positive correlation between CRP and WBC was observed only on day 1 (ρ = 0.58, p < 0.05); no significant correlations were found from day 7 onward.

Conclusion: The postoperative kinetics of point-of-care CRP and total WBC counts are fundamentally different after TPLO. CRP provides a reliable, dynamic profile that accurately reflects the resolution of acute inflammation in uncomplicated cases, whereas total WBC count is an unreliable biomarker due to persistent non-specific elevation from surgical stress. These findings support serial point-of-care CRP measurement as a superior objective tool for monitoring postoperative recovery and early detection of complications in dogs undergoing TPLO.