Usefulness of C-reactive protein and serum amyloid A in early detection of postoperative infectious complications to tibial plateau leveling osteotomy in dogs

The companion dog as a model for inflammaging: a cross-sectional pilot study

Inflammaging, the chronic, progressive proinflammatory state associated with aging, has been associated with multiple negative health outcomes in humans. The pathophysiology of inflammaging is complex; however, it is often characterized by high serum concentrations of inflammatory mediators such as tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and C-reactive protein (CRP). Few studies have evaluated the effects of age on inflammatory cytokines in companion dogs, and most of these studies included dogs of a single breed. In this cross-sectional study, we measured multiple circulating inflammatory markers and hematological parameters in banked serum samples from 47 healthy companion dogs of various breeds enrolled in the Dog Aging Project. Using univariate linear models, we investigated the association of each of these markers with age, sex, body weight, and body condition score (BCS), a measure of obesity in the dog. Serum IL-6, IL-8, and TNF-α concentrations were all positively associated with age. Lymphocyte count was negatively associated with age. Platelet count had a negative association with body weight. IL-2, albumin, cholesterol, triglyceride, bilirubin, S100A12, and NMH concentrations were not associated with age, weight, BCS, or sex after adjustment for multiple comparisons. Our findings replicate previous findings in humans, including increases in IL-6 and TNF-α with age, giving more evidence to the strength of the companion dog as a model for human aging.

Plasma procalcitonin kinetics in healthy dogs and dogs undergoing tibial plateau leveling osteotomy

BACKGROUND

Procalcitonin (PCT) is a well-established biomarker for bacterial infection in human patients.

OBJECTIVES

We aimed to analyze the kinetics of plasma PCT (pPCT) in healthy dogs and dogs with canine cranial cruciate ligament (CCL) rupture undergoing tibial plateau leveling osteotomy (TPLO).

METHODS

This prospective, longitudinal study included 15 healthy dogs and 25 dogs undergoing TPLO. Hematology, pPCT, and C-reactive protein (CRP) were assessed on 3 consecutive days in healthy dogs and 1 day preoperatively and days 1, 2, 10, and 56 postoperatively. Inter- and intraindividual variability of pPCT were assessed in healthy dogs. Median pPCT concentrations of dogs with CCL rupture preoperatively were compared with healthy controls, and median pPCT concentrations, as well as percentage change post anesthesia, arthroscopy, and TPLO, were compared with baseline. For the correlation analysis, the Spearman rank correlation test was used.

RESULTS

Inter- and intraindividual variabilities of pPCT in healthy dogs were 36% and 15%, respectively. Median baseline pPCT concentrations were not significantly different between healthy dogs (118.9 pg/mL; IQR: 75.3-157.3 pg/mL) and dogs undergoing TPLO (95.9 pg/mL; IQR: 63.8-117.0 pg/mL). Plasma PCT concentrations were significantly lower immediately post- than preoperatively (P < 0.001). CRP, WBC, and neutrophil concentrations increased significantly on post-OP day 2 and had normalized by day 10.

CONCLUSIONS

These results indicate that CCL rupture, as well as anesthesia, arthroscopy, and TPLO combined, are not associated with increased pPCT concentrations in dogs with uncomplicated recovery. Considering the high intraindividual variability, individual serial measurements rather than a population-based reference interval should be considered.

Surgical treatment of cranial cruciate ligament disease in dogs using Tibial Plateau Leveling Osteotomy or Tibial Tuberosity Advancement-A systematic review with a meta-analytic approach

Tibial Plateau Leveling Osteotomy (TPLO) or Tibial Tuberosity Advancement (TTA) are commonly used surgical techniques for correction of cranial cruciate ligament (CCL) rupture in dogs. This systematic review aims to investigate whether one technique is superior to the other. Seventy-two studies on surgical management of CCL rupture have been identified and evaluated in regard of subjective and objective gait analysis criteria, development of osteoarthritis (OA), thigh circumference measurements, goniometry, joint stability, pain and complication rates. Almost half (47.2 %) of the studies were considered of low quality of evidence, leading to high heterogeneity in quality among studies; this posed a major limitation for an evidence-based systematic review of both surgical techniques. Out of 72 studies, there were only eleven blinded randomized clinical trials, of which five were rated with a low overall risk of bias. However, both techniques were considered to be successful management options. Subjective and objective gait analysis revealed no lameness at long-term evaluation for the majority of the patients. However, it appeared that TTA lead to better OA scores up to 6 months postoperatively, while TPLO had a lower rate of surgical site infections. In summary, no method can be clearly preferred, as most of the study evaluated were subpar. Studies with a high level of evidence are therefore urgently needed for such a common surgical procedure.

Chicken antibodies are highly suitable for particle enhanced turbidimetric assays

Antibody-based assays are commonly used in clinical laboratories for analyzing plasma, serum and other samples for particular protein markers. Although such assays have been traditionally based on antibodies raised in mammals (e.g., mice, rabbits, goats), there are several advantages of using avian antibodies (IgY) raised in chickens, including production volumes, costs, and ethical/animal welfare considerations. A further disadvantage of using mammalian IgG in such assays is the potential for agglutination when exposed to rheumatoid factor (RF) in serum. However, when used in the free form the immune complexes formed with avian antibodies have been reported to have less ability than those formed with mammalian antibodies to cause the light scatter which are used for instrument measurement. In addition, when the amount of antigen exceeds the maximum precipitating point in relation to the amount of antibody, there is a rapid decline in the absorbance values of the immune complexes (antigen excess) when IgY is used. However, when avian antibodies are conjugated to a substrate and used in particle enhanced turbidimetric assays (PETIA), these problems are avoided. Here we investigated three clinical assays using chicken antibodies, one using free (unbound) IgY and two with IgY-based PETIA. The IgY PETIA demonstrated a strong scatter response, even at high antigen concentrations in contrast to the steep decline seen with free IgY antibodies. IgY PETIA reagents can provide test results with low coefficient of variation (<1% for duplicate samples). We also investigated the effect of RF on agglutination of mammalian antibodies (IgG from mouse, rabbit, sheep, and human) and chicken antibodies. Whereas agglutination was observed with all the mammalian antibodies in the presence of RF, this was not observed at all with chicken IgY. Our results support the growing body of evidence that chicken egg yolks can thus be a valuable source of antibodies for use in PETIA in clinical laboratories.

Serial evaluation of thoracic radiographs and acute phase proteins in dogs with pneumonia

Background

Acute phase proteins (APP) may guide treatment of pneumonia in dogs but correlations with radiographic abnormalities are poorly characterized.

Objectives

Develop a thoracic radiographic severity scoring system (TRSS), assess correlation of radiographic changes with APP concentrations, and compare time to APP and radiograph normalization with duration of antimicrobials treatment.

Animals

Sixteen client‐owned dogs, 12 with aspiration pneumonia, and 4 with community‐acquired pneumonia.

Methods

Concentrations of C‐reactive protein (CRP), serum amyloid A (SAA), and haptoglobin were measured on days 1, 3, 7, 14, 28, and 60 and orthogonal 2‐view thoracic radiographs were obtained on days 1, 7, 14, 28, and 60. Treatment was clinician‐guided and blinded to APP concentrations. Radiographic severity scores were assigned by blinded, randomized retrospective review by 2 board‐certified radiologists with arbitration by a third radiologist.

Results

Median (interquartile range [IQR]) time to normalization of CRP (7 days [7‐14]) and SAA concentrations (7 days [7‐14]) were shorter than antimicrobial treatment duration (17.5 days [14.5‐33.5]; P = .001 and .002, respectively) and TRSS normalization (14 days [8.8‐52], P = .02 and .02, respectively). The CRP and SAA concentrations were positively correlated with TRSS (CRP r_s, 0.643; SAA r_s, 0.634; both P < .0001). Both CRP and SAA identified normal thoracic radiographs area under the curve (AUC) 0.873 and 0.817, respectively, both P < .0001. Interobserver agreement for TRSS assignment was moderate (κ, .499; P < .0001).

Conclusion and Clinical Importance

Concentrations of CRP and SAA normalized before radiographic resolution and before clinicians discontinued antimicrobial treatment. The CRP and SAA concentrations may guide duration of antimicrobial treatment for dogs with pneumonia.

Acute phase protein response and changes in lipoprotein particle size in dogs with systemic inflammatory response syndrome

Background

Improved methodology to measure acute phase proteins and determination of lipoprotein particle‐size distribution (PSD) could be clinically useful in dogs with systemic inflammatory processes.

Objectives

Evaluate an immunoturbidometric assay for serum amyloid A (SAA) and lipoprotein PSD in dogs with sepsis, nonseptic systemic inflammation, and in healthy controls. Correlate dyslipidemic changes with SAA and C‐reactive protein (CRP) concentrations.

Animals

Twenty‐five dogs with sepsis, 15 dogs with nonseptic systemic inflammation, and 22 healthy controls.

Methods

Prospective, case‐control study. Variables included SAA, CRP, and electrophoretic subfractionation of high‐ and low‐density lipoproteins (HDL, LDL). Continuous variables were compared using ANOVA or Kruskal‐Wallis tests with linear regression or Spearman's rank correlation used to assess relationships between variables.

Results

Median SAA and CRP concentrations were greater in dogs with sepsis (SAA 460 mg/L, interquartile range [IQR] 886 mg/L; CRP 133.2 mg/L, IQR 91.6 mg/L) and nonseptic inflammation (SAA 201 mg/L, IQR 436 mg/L; CRP 91.1 mg/L, IQR 88.6 mg/L) compared to healthy dogs (SAA 0.0 mg/L, IQR 0.0 mg/L; CRP 4.9 mg/L, IQR 0.0 mg/L) P < .0001. A cutoff of >677.5 mg/L SAA was 43.2% sensitive and 92.3% specific for sepsis. Low‐density lipoprotein was higher in dogs with sepsis 29.6%, (mean, SD 14.6) compared to 14.4% (mean, SD 5.6) of all lipoproteins in healthy controls (P = .005). High‐density lipoprotein was not associated with CRP but was negatively correlated with SAA (r_s −0.47, P < .0001). Subfractions of LDL and HDL differed between groups (all P < .05).

Conclusions and Clinical Importance

Measurement of SAA using the immunoturbidometric assay evaluated in this study and lipoprotein PSD in dogs with inflammation might help distinguish septic from nonseptic causes of inflammation.

Serial analysis of blood biomarker concentrations in dogs with pneumonia, septic peritonitis, and pyometra

BACKGROUND

Prolonged antimicrobial drug (AMD) treatment is associated with antimicrobial resistance development. Biomarker measurement may aid treatment decision-making.

OBJECTIVES

Investigate temporal changes in blood biomarker concentrations in dogs undergoing treatment for pulmonary and intra-abdominal infections; compare time to biomarker concentration normalization with duration of clinician-directed AMD treatment.

ANIMALS

Forty-two client-owned dogs with pneumonia (n = 22), septic peritonitis (n = 10), or pyometra (n = 10).

METHODS

Plasma concentrations of C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin, procalcitonin, nucleosomes, cell-free DNA (cfDNA), high-mobility group box-1 (HMGB1), CC-motif chemokine ligand-2 (CCL2), CXC-motif chemokine ligand-8 (CXCL8), and keratinocyte chemoattractant-like (KC-Like) were quantitated in samples collected on days 1, 3, 7, 14, 28, and 60. Treatment was directed by clinicians blinded to biomarker concentrations.

RESULTS

Concentrations of CCL2, CRP, and KC-Like were maximal on D1, concentrations of SAA, cfDNA, HMGB1, and nucleosomes were maximal on D3 and haptoglobin concentrations were maximal on D7. These maximal concentrations were significantly different from those on D60. Concentrations of CRP and SAA decreased by 80% from peak and into respective reference intervals before AMDs were discontinued. For CRP, the median (interquartile range [IQR]) times to 20% peak and normal were 7 (6-9) and 7 (6-12) days, respectively, and for SAA they were 4 (4, 5) and 6 (5-8) days, respectively, compared to a median (IQR) duration of AMD prescribing of 16 (12-23) days (all P < .0001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Biomarker concentrations normalized within 7 to 14 days. Serial measurements of CRP and SAA might aid identification of disease resolution and could help guide AMD prescription decision-making.

Prospective evaluation of novel biomarkers of acute kidney injury in dogs following cardiac surgery under cardiopulmonary bypass

OBJECTIVE

To assess the occurrence of acute kidney injury (AKI) in dogs undergoing cardiac surgery under cardiopulmonary bypass (CPB) and explore associations between traditional and novel serum and urinary biomarkers.

DESIGN

Prospective cohort study conducted between July 2018 and April 2019.

SETTING

University teaching hospital.

ANIMALS

Nineteen dogs undergoing cardiac surgery under CPB with preoperative serum creatinine <140 μmol/L (<1.6 mg/dl).

INTERVENTIONS

Blood and urine samples were obtained at 4 time points: preoperatively following general anesthesia induction, immediately postoperatively, and 2 and 4 days postoperatively (T₁ , T₂ , T₃ , and T₄ ). AKI was defined as an increase in serum creatinine ≥26.4 μmol/L (≥0.3 mg/dl) above baseline within 48 hours. Serum creatinine, C-reactive protein (CRP), symmetric dimethylarginine (SDMA), inosine, beta-aminoisobutyric acid (BAIB), urinary clusterin (uClus), and urinary cystatin B (uCysB) were measured. Data were log-transformed (log₁₀ ) when appropriate and assessed using linear mixed-effects models.

MEASUREMENTS AND MAIN RESULTS

AKI occurred in 3 of 19 dogs (15.8%, 95% confidence interval: 0.047-0.384). Inosine increased at T₂ (adjusted mean ± standard error: 53 ± 5.6) in all dogs, and then gradually decreased. Log₁₀ uCysB increased at T₂ (2.3 ± 0.1) in all dogs and remained high. Log₁₀ CRP and log₁₀ uClus increased significantly at T₃ (1.9 ± 0.1 and 3.6 ± 0.1, respectively) in all dogs and remained increased. There was a significant positive association between serum creatinine and SDMA (P < 0.001, estimate ± standard error: 0.06 ± 0.00), between log₁₀ CRP and log₁₀ uClus (P < 0.001, 0.35 ± 0.08), between SDMA and creatinine as well as between SDMA and BAIB (P < 0.001, 11.1 ± 0.83 and P < 0.001, 1.06 ± 0.22, respectively) for all dogs at all time points.

CONCLUSIONS

Inosine and uCysB concentrations changed in all dogs immediately following a surgery under CPB and may indicate tubular injury. Further studies are required to ascertain the usefulness of those biomarkers in early detection of AKI.

Preoperative serum C-reactive protein concentration can be used to detect gallbladder rupture in dogs with gallbladder mucocele

OBJECTIVE

To determine whether serum C-reactive protein (CRP) concentration could be used to detect gallbladder rupture (GBR) prior to surgery in dogs undergoing cholecystectomy for treatment of gallbladder mucocele (GBM).

ANIMALS

45 dogs that underwent cholecystectomy because of GBM at a companion animal referral hospital from 2017 to 2020.

PROCEDURES

Electronic medical records were reviewed, and dogs were included if serum CRP concentration had been measured within 24 hours prior to cholecystectomy. Dogs were grouped as to whether the gallbladder was found to be ruptured or intact during surgery. Accuracy of using preoperative CRP concentration to predict GBR was compared with accuracy of abdominal ultrasonography and other preoperative blood tests.

RESULTS

GBR was present in 15 dogs at the time of surgery. Median preoperative CRP concentration was significantly higher in dogs with GBR (15.1 mg/dL; interquartile range, 7.4 to 16.8 mg/dL) than in dogs with an intact gallbladder (2.65 mg/dL; interquartile range, 0.97 to 13.4 mg/dL). Sensitivity, specificity, and accuracy of using preoperative CRP concentration to predict GBR were 100%, 67%, and 78%, respectively.

CLINICAL RELEVANCE

Measurement of preoperative CRP concentration provided excellent sensitivity and moderate specificity for detection of GBR in dogs undergoing cholecystectomy because of GBM. Accuracy of using preoperative CRP concentration for detection of GBR was not superior to the accuracy of preoperative abdominal ultrasonography. However, when CRP concentration was combined with results of ultrasonography, the sensitivity, specificity, and accuracy for detection of GBR were 100%, 93%, and 96%, respectively.

Serum C-reactive protein and iron levels following gonadectomy are not modified by perioperative administration of robenacoxib to dogs

The aim of this study was to evaluate the perioperative effects of robenacoxib on serum C-reactive protein (CRP) and iron concentrations in dogs undergoing gonadectomy. In a prospective, blinded, controlled clinical trial, 60 healthy dogs were randomly assigned to receive preoperative subcutaneous injection of either robenacoxib [2 mg/kg body weight (BW)], meloxicam (0.2 mg/kg BW), or saline (0.04 mL/kg BW), followed by oral administration over 72 h (robenacoxib: 2 to 4 mg/kg BW; meloxicam: 0.1 mg/kg BW; saline: gelatin capsules). Blood samples were taken before surgery and 12, 24, 48, 72 h, and 7 d after surgery. Pain scores were assessed via the short-form Glasgow Composite Pain Scale over 72 h postoperatively. C-reactive protein (CRP) and iron serum levels increased and decreased (P < 0.01, both), respectively, after surgery and returned to baseline within 1 wk. No differences were observed among treatments (P > 0.05) or based on surgery/gender (P > 0.05). Pain assessment revealed a higher incidence of treatment failure in saline (6 females versus 2 and 1 female in robenacoxib and meloxicam, respectively). In conclusion, robenacoxib and meloxicam had no influence on postoperative CRP or iron in dogs, which suggests that these nonsteroidal anti-inflammatory drugs (NSAIDs) do not have a relevant effect on these biomarkers.

Relationship between vitamin D status and clinical outcomes in dogs with a cranial cruciate ligament rupture

Cranial cruciate ligament rupture (CCLR) is one of the most common orthopaedic disorders diagnosed in dogs yet the factors which influence postoperative clinical outcomes are poorly understood. Low vitamin D status has been linked to poorer clinical outcomes in human patients undergoing elective orthopaedic surgery. The aim of this study was to examine the relationship between pre-operative vitamin D status, as defined by serum 25 hydroxyvitamin D (25(OH)D) concentrations, and initial disease severity and clinical outcomes in dogs undergoing surgical treatment for a CCLR. Serum 25(OH)D concentrations were measured in 44 dogs with a CCLR on the day before surgery. C-reactive protein concentrations were measured at a median time of 1 day post-surgery and the patient's clinical and radiographic response to CCLR surgical treatment was assessed at a median timepoint of 60 days post-surgery. Serum 25(OH)D concentrations in dogs with a CCLR was not significantly different to a population of healthy dogs (median 74.1 nmol/L and 88.40 nmol/L, respectively). There was no significant correlation between pre-operative serum 25(OH)D concentrations and length of pre-diagnosis clinical signs, pre-operative lameness scores or day 1 post-operative CRP concentrations. Thirty nine of the 44 dogs were re-examined at a median 60 days post-surgery. There was no relationship between the day 60 lameness scores and pre-operative serum 25(OH)D concentrations. In summary, we discovered that the vitamin D status of dogs with a CCLR was not significantly lower than healthy dogs and pre-operative serum 25(OH)D concentrations were not correlated to either pre-surgical disease severity or post-operative clinical outcomes.

Effects of surgery on free and total 25 hydroxyvitamin D concentrations in dogs

Background

It is unclear whether a low total 25(OH)D concentration is a cause or consequence of illnesses. To address this knowledge gap, studies measuring free and total 25(OH)D during the evolution and resolution of an inflammatory process are required.

Objectives

Serum total and free 25(OH)D concentrations would transiently decline after cruciate surgery in dogs.

Animals

Seventeen client‐owned dogs with a spontaneous cranial cruciate ligament rupture (CCLR).

Methods

A longitudinal cohort study involving the measurement of serum concentrations of total and free 25(OH)D, total calcium, creatinine, albumin, phosphate, C‐reactive protein and plasma ionized calcium, at 1 day before and a median time of 1 and 60 days after surgical treatment of CCLR.

Results

Median serum concentrations of total 25(OH)D before surgery (80.3 nmoL/L [range, 43.5‐137.3]) significantly declined immediately after surgery; (64.8 nmoL/L [range, 36.3‐116.5] 1 day after surgery, P < .005) before increasing to become nonsignificantly different from concentrations before surgery at day 60 after surgery (median 78.0 nmoL/L [range, 24.2‐115.8], P = .14). In contrast, median free 25(OH)D concentrations before surgery (7.6 pg/mL [range, 3.8‐12.2]) significantly increased immediately after surgery (9.2 pg/mL [range, 5.2‐15.7], P < .05) before declining to become nonsignificantly different from before surgery concentrations at day 60 after surgery (median 6.2 pg/mL [range, 4.0‐15.8], P = .37).

Conclusion and Clinical Importance

This study reveals the difficulties of assessing vitamin D status in dogs following elective surgery.

Characterization of C-reactive protein in dogs undergoing medial patellar luxation surgery

C-reactive protein (CRP) is a major acute phase protein used to monitor response to treatment during surgical recovery. Depending on the anatomical problem, surgery type and technique, the level of CRP can change drastically. The aim of this study was to describe the changes in CRP and white blood cell (WBC) levels following surgery for medial patellar luxation in otherwise healthy dogs. Twenty-two dogs completed the study. CRP was measured using a commercially available dry chemistry slide on a commercially available in-clinic analyser. Analyses were performed using the Wilcoxon Rank Sum test and a mixed effects Poisson regression model. A significant change in CRP levels was found between the pre-anesthetic and 24 hr post-surgical timepoint with a median difference of 92.0 mg/dL (P < 0.001). Though a median drop in the CRP value of 13.9 mg/dL was observed between the 24 hr and 48 hr post-surgical time period, the result was not statistically significant (P = 0.456). Similarly, there was a significant increase in WBC between the pre-anesthetic and 24-hr post-surgical time point (P < 0.001) followed by a significant decrease in WBC between the 24 hr and 48-hr post-surgical time points (P = 0.015). In this study population, CRP levels were observed to aid in monitoring of the overall health of the dogs following surgery for medial patellar luxation. The results of this study suggest that both CRP and WBC values significantly increase by 24 hr but where CRP levels remain elevated through 48 hr post-surgery, WBC showed a significant drop between 24 and 48 hr. Further investigation into the length of time for both CRP and WBC to reach basal levels in this particular type of surgery would be of value to monitor recovery from surgery.

Placebo-controlled pilot study of the effects of an eggshell membrane-based supplement on mobility and serum biomarkers in dogs with osteoarthritis

Osteoarthritis (OA) is a debilitating disease in dogs. Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used to treat OA; however, many dogs do not obtain adequate pain relief with an NSAID alone. This pilot study evaluated the systemic anti-inflammatory and mobility enhancing effects of an eggshell membrane-based nutritional supplement in dogs with OA-associated pain and mobility impairment. Twenty-seven dogs with OA-associated pain were enrolled into a randomized, double-masked, placebo-controlled, proof of principle pilot study and received either placebo or an eggshell membrane-based nutritional supplement over a 12-week period. Inflammatory biomarkers (IL-2, IL-6, IL-8, tumor necrosis factor-α, C-reactive protein, S100A12, and N-methylhistamine) were measured at Day 0 and Day 84. Owner questionnaires (CBPI and LOAD) were completed at Day 0, Day 42, and Day 84. Differences between groups over time were calculated. Twenty-two dogs completed the pilot study. Inflammatory biomarker IL-2 decreased in the supplement group, compared to the placebo group. Although small, the difference was statistically significant at an alpha of 0.1 (P=0.069). LOAD scores were numerically lower in the supplement group, but not significantly different from the placebo group at Day 0. Day 84 LOAD scores were significantly lower in the supplement group compared to the placebo group (P=0.034). CBPI results did not show the same pattern. The changes in biomarkers and LOAD scores were small, and do not provide definitive evidence of positive effects. However, these pilot results provide a rationale for performing a larger placebo-controlled study of the potential effects of the eggshell membrane-based nutritional supplement.

Changes in canine C-reactive protein levels following orthopaedic surgery: a prospective study

C-reactive protein (CRP) is a powerful biomarker for inflammation, infection and sepsis. However, no reports have investigated canine CRP (c-CRP) concentration changes after orthopaedic procedures. If c-CRP changes were better characterized, it may be possible to identify postoperative complications more quickly. The purpose of this study was to clarify the characteristic changes in serum c-CRP after orthopaedic surgery in dogs. Blood samples were collected from 98 dogs on Day 0 (preoperatively), and then on Days 1, 4, 7, 10 and 13 postoperatively. Day 1 blood sampling was performed 12–24 h postoperatively. We classified the dogs into four groups based on changes in c-CRP pre- to postoperatively. Group 1 dogs showed a peak c-CRP concentration on Day 1, followed by decreases of ≥ 1 mg/dL. Group 2 dogs showed changes in c-CRP concentration by Day 4 that were within ± 1 mg/dL compared with Day 1. Dogs in Group 3 showed a peak c-CRP concentration on Day 4, followed by decreases of ≥ 1 mg/dL. Group 4 dogs showed an initial decrease in c-CRP, then an increase of ≥ 1 mg/dL. Group 1 was the largest group, with 63 dogs. c-CRP on Days 0, 1, 4, 7, 10 and 13 was 0.83 ± 1.03 mg/dL, 8.10 ± 3.15 mg/dL, 3.76 ± 1.94 mg/dL, 1.63 ± 0.92 mg/dL, 0.96 ± 0.70 mg/dL and 0.68 ± 0.51 mg/dL, respectively. Serum c-CRP concentration on Day 1 was significantly higher than at every other timepoint (P < 0.001). In Group 2, surgical site complications were confirmed in 9/15 dogs. In Group 3, surgical site complications were confirmed in 7/14 dogs. In Group 4, two surgical site problems and three surgical site infections were observed, and visceral disease was found in one dog. In Group 1, peak c-CRP was seen on Day 1 postoperatively in 63 dogs (64%), with c-CRP level decreasing by half at each subsequent measurement, which may describe a typical c-CRP change in orthopaedic patients. If deviation from this typical change is observed postoperatively, as in Groups 2–4, this may suggest possible complications.