Clinical relevance of positive intraoperative bacterial culture in tibial plateau leveling osteotomy in dogs: a retrospective study

BACKGROUND

Tibial plateau leveling osteotomy (TPLO) belongs to the most frequently used surgical method for the treatment of cranial cruciate ligament rupture in dogs. Surgical site infection (SSI) is one of the possible postoperative complications. The aim of this study was to evaluate the diagnostic value of intraoperative bacterial culture as a tool for the detection of intraoperative bacterial contamination progressing to infection development in canine TPLO. Electronic patient records from dogs who underwent TPLO between January 2018 to December 2020 were retrospectively reviewed. Intraoperative bacterial culture results, used antimicrobial drugs and presence of SSI were recorded.

RESULTS

Ninety-eight dogs were included in the study. SSI rate was 10.2%. All dogs who developed SSI (n = 10) had negative intraoperative bacterial cultures. None of the dogs with positive intraoperative bacterial culture (n = 6) developed SSI. The most cultured bacteria causing SSI was Staphylococcus pseudintermedius (n = 4).

CONCLUSIONS

Intraoperative bacterial culture in dogs undergoing TPLO is not suitable as a predictor of surgical site infection.

Single institution retrospective study evaluating the frequency of implant removal and associated risk factors following open fracture fixation in 80 cases (2010-2020)

BACKGROUND

Open fractures occur commonly in small animals and are characterised by contamination of the fracture site. While never quantified, it is believed that open fractures stabilised with internal implants are at a higher risk for requiring explantation. This retrospective study determines the frequency and risk factors for explantation following use of internal fixation. Medical records of client-owned dogs and cats with an open fracture, between 2010 and 2020 stabilised using internal implants, were included. Data retrieved included signalment, cause and characterisation of the fracture, comorbidities, preexisting infections, and all details related to anesthesia and surgery. Pre-, Peri- and post-operative antibiotic use were detailed. All cases were followed to clinical union. Postoperative complications, including requirement for implant removal were recorded and classified as major or minor. Associations between potential risk factors and need for explantation were assessed.

RESULTS

Of 80 cases, 72 (90%) were dogs and eight (10%) cats. Major complications were encountered in 23 (28.75%) cases and minor complications in 16 (20%) cases. Explantation was performed in 17 cases (21.25%). Out of 72 dogs, 13 required explantation (18%) whereas four of the eight cats needed implants removed (50%). Only diagnosis of postoperative infection was associated with an increased risk of explantation (RR 2.77; 95% CI 1.25; 6.15; p = 0.045).

CONCLUSION

Approximately 1 in 5 open fractures stabilised using internal fixation can be anticipated to require explantation, with cats potentially being at a higher risk than dogs. Cases diagnosed with postoperative infection are at a higher risk for requiring implant removal.

Effects of Angled Dynamic Compression Holes in a Tibial Plateau Levelling Osteotomy Plate on Cranially Directed Fragment Displacement

OBJECTIVE

 To compare angled dynamic compression holes in a tibial plateau levelling osteotomy (TPLO) plate to a commercially available TPLO plate in an ovine cadaveric model.

STUDY DESIGN

 Ovine tibias (40 bones) were mounted on a custom-made securement device and radiopaque markers were placed to aid radiographic measurements. A standard TPLO procedure was performed on each tibia with either a custom-made six-hole 3.5 mm angled compression hole plate (APlate) or a six-hole 3.5 mm standard commercial plate (SPlate). Radiographs were obtained before and after tightening of the cortical screws and evaluated by an observer blinded to the plate. Measurements of cranio-caudal displacement (CDisplacement), proximo-distal displacement (PDisplacement) in relation to the long axis of the tibia, and change in tibial plateau angle (TPA) were determined.

RESULTS

 CDisplacement was significantly greater in APlate (median 0.85 mm, Q1-Q3: 0.575-1.325 mm) compared to SPlate (median 0.00 mm, Q1-Q3: -0.35-0.50 mm, p < 0.0001). There were no significant differences in the PDisplacement (median 0.55 mm, Q1-Q3: 0.075-1.00 mm, p = 0.5066) or TPA change (median -0.50°, Q1-Q3: -1.225-0.25°, p = 0.1846) between the two plate types.

CONCLUSION

 APlate increases cranially directed displacement of the osteotomy in a TPLO procedure without causing TPA change. The reduced interfragmentary distance across the whole osteotomy could improve osteotomy healing compared to standard commercial TPLO plates.

Implant removal rate after partial carpal arthrodesis in dogs: A retrospective analysis of 22 cases

Introduction

The purpose of this study is to determine the rate of implant removal after partial carpal arthrodesis and to investigate factors associated with implant removal.

Methods

Case records of 22 dogs that underwent partial carpal arthrodesis at two private veterinary referral hospitals were reviewed. Details retrieved were body weight at time of surgery, sex, neuter status, breed, age, cause of carpal hyperextension injury, joint(s) involved in carpal hyperextension injury, laterality, type of implant, administration of post-operative antibiotics, post-operative outcome and indication for implant removal. Association between these factors and implant removal was evaluated.

Results

Of 22 partial carpal arthrodesis, 12 (55%) had implant removal due to persistent lameness and 9/12 (75%) returned to full and acceptable function after implant removal. Indications for implant removal were implant interference (8), infection (4), and migration (1). When comparing type of implant, there was a significant difference when observing implant removal rates (p = 0.04). All 5 dogs with pins and wires (100%) required implant removal. Of 17 dogs with a plate, 7 (41.2%) required implant removal. Implant removal was performed on average 114 days post-operative.

Discussion

Implant removal after partial carpal arthrodesis was frequent and was commonly indicated due to pin and wire fixation or plate implant interference. This study may impact how we prepare clients for potential post-operative complications and implant removal when recommending partial carpal arthrodesis.

Complications after proximal abducting ulnar osteotomy and prognostic factors in 66 dogs

Objective

To report complications and prognostic factors in dogs undergoing proximal abducting ulnar osteotomy (PAUL). To evaluate the ability to predict complications on the basis of post‐operative radiographic examination.

Study Design

Retrospective cohort study.

Animals

Sixty‐six dogs.

Methods

Medical records of dogs treated with PAUL between 2014 and 2019 were reviewed for demographics, intraoperative findings, and post‐operative complications. Post‐operative radiographs were reviewed by two masked expert orthopedic surgeons, who were asked to predict the likelihood of major mechanical complications. The prognostic value of variables was tested with univariate and multivariable logistic regression. Inter‐investigator agreement to predict complications was evaluated with two‐by‐two tables and kappa coefficient.

Results

Seventy‐four PAULs in 66 dogs were included. Duration of follow‐up ranged from 12 to 75 months (median: 53 months). Post‐operative complications were documented in 19/74 limbs (16 dogs), including major complications in 13 limbs. These complications consisted mainly of non‐union (six limbs), implant failure (two limbs), and infection (two limbs) requiring revision surgery in nine limbs. Body weight was the only variable associated with an increased risk of post‐operative complications (p = .04). Agreement between expert predictions was low (respectively k = −0.08 and k = 0.11).

Conclusion

Major complications were reported in one fourth of limbs treated with PAUL and were more likely as body weight increased. Suboptimal plate and screw placement or osteotomy reduction on post‐operative radiographs were poorly predictive of complications.

Clinical Significance

Complications are fairly common after PAUL, particularly in heavier dogs, and post‐operative radiographic examination seems unreliable to predict those.

Effect of ultraviolet-C light on the environmental bacterial bioburden in various veterinary facilities

OBJECTIVE

To determine the effect of a mobile UV-C disinfection device on the environmental bacterial bioburden in veterinary facilities.

SAMPLES

40 swab samples of surfaces from the operating theaters of 3 veterinary hospitals and 1 necropsy laboratory.

PROCEDURES

Various surfaces were swabbed, and collected material was eluted from the swabs in PBSS. Then, an aliquot of the sample fluid was processed with a bacteria-specific rapid metabolic assay to quantify bacterial bioburden. Each site was then treated with UV-C light with an automated disinfection device for approximately 45 minutes. The same surfaces were swabbed following UV-C treatment, and bioburden was quantified. The bioburden at additional time points, including after a second UV-C treatment, was determined for the small animal operating theater.

RESULTS

All surfaces at all sites had a persistent viable bacterial population following manual cleaning. Disinfection with UV-C achieved a mean bioburden reduction of 94% (SD, 5.2%; range, 91% to 95%) for all surfaces, compared with manual disinfection alone. Repeated UV-C treatment of the small animal operating theater reduced mean bioburden by 99% (SD, 0.8%), including no detectable bacteria on 4 of 10 surfaces.

CONCLUSIONS AND CLINICAL RELEVANCE

Disinfection with UV-C light may be a beneficial adjunct method for terminal disinfection of veterinary operating theaters to reduce environmental bioburden. (Am J Vet Res 2021;82:582-588).

Timing of and risk factors for deep surgical site infection requiring implant removal following canine tibial plateau leveling osteotomy

OBJECTIVE

To identify demographic risk factors for deep surgical site infection (SSI) requiring tibial plateau leveling osteotomy (TPLO) implant removal and time to implant removal.

ANIMALS

Four hundred and thirty-three dogs that underwent a TPLO (144 that developed a deep SSI and required implant removal, 289 that did not).

STUDY DESIGN

Retrospective case-control study.

METHODS

Records of dogs undergoing implant removal due to a deep SSI after TPLO between 2006 and 2018 at two referral centers were reviewed. These records were frequency-matched by date to dogs undergoing TPLO that did not require implant removal. Multivariable analyses tested associations between demographics and implant removal as well as timing of implant removal.

RESULTS

Deep SSI and implant removal occurred in 144 of 4813 (3.0%; 95% CI: 2.5, 3.5) dogs treated with TPLO. Implant removal was performed at a median of 279 days (range 49-2394 days) postoperatively. Male dogs (OR 1.8; 95% CI: 1.2, 2.7) and German Shepherd dogs (GSDs) (OR 7.4; 95% CI: 2.6, 20.5) were associated with plate removal. Earlier TPLO plate removal was associated with GSDs only (HR 2.4; 95% CI: 1.4, 4.1).

CONCLUSION

Implant removal due to SSI after TPLO was uncommon, although male dogs and GSDs seemed predisposed to this complication.

SIGNIFICANCE

These demographic risk factors can be used to educate owners regarding perioperative management.

Recovery of borderline oxacillin-resistant Staphylococcus pseudintermedius (BORSP) from bone and soft tissue of a rheumatoid arthritis patient with severe osteoporosis: transmission from the family dog

We report a case of borderline oxacillin-resistant S. pseudintermedius (BORSP) in a rheumatoid arthritis patient with severe osteoporosis. The organism is also resistant to erythromycin and clindamycin. We also present clear evidence on transmission from the family dog.

Plate Removal after Internal Fixation of Limb Fractures: A Retrospective Study of Indications and Complications in 48 Horses

OBJECTIVE

 The aim of this study was to determine the indications for, and complications of, plate removal surgery in horses that underwent internal fixation of limb fractures.

STUDY DESIGN

 Medical records of horses presented to our hospital between 1990 and 2015 for the removal of plates after treatment of limb fractures were reviewed. Data collected at the time of initial presentation, including signalment, history, fracture features and treatment and information about the indications, timing and complications of implant removal were reviewed.

RESULTS

 The most common bones involved were the ulna (n = 19) and third metacarpal and metatarsal bones (n = 14). A total of 63 plates were removed from 48 horses during 53 separate surgeries, and the complication rate was 6/48; six horses had complications related to implant removal, which included persistent infection (n = 1) and refracture (n = 5). Complications related to implant removal were associated with comminuted fractures (p = 0.002), age > 3 years (p = 0.016) and the presence of surgical site infection (p = 0.001).

CONCLUSION

 Plate removal after fracture healing is necessary in patients with implant-associated clinical signs. There is a strong relationship between the complication rate and the degree of comminution of the original fracture, increasing age and the presence of surgical site infection. The surgeon must be aware of these risk factors when planning plate removal.

Influence of administration of antimicrobial medications after tibial plateau leveling osteotomy on surgical site infections: A retrospective study of 308 dogs

OBJECTIVE

To determine the influence of prophylactic administration of oral antimicrobial medications after tibial plateau leveling osteotomy (TPLO) on surgical site infections (SSI) and antimicrobial-resistant infections.

STUDY DESIGN

Retrospective study.

SAMPLE POPULATION

Dogs treated with unilateral TPLO (n = 308) between January 2013 and December 2015.

METHODS

Medical records were reviewed for signalment, surgically treated limb, duration of surgery and anesthesia, postoperative administration of antimicrobial medications, antibiotic agent, surgeon, and development of SSI. Statistical analyses included descriptive statistics, simple linear regression, analysis of variance, Fisher's protected least significant difference, and χ² testing.

RESULTS

Data were collected from records of 31 dogs that did not receive antimicrobial medications and 277 dogs that did receive oral antimicrobial medications for 14 days after TPLO. Superficial incisional SSI was detected in two of 31 dogs that did not receive antimicrobial medications and in 48 of 277 dogs that did receive antimicrobial medications (P = .1194). Deep incisional SSI occurred in two of 31 dogs that did not receive antimicrobial medications and in 27 of 277 dogs that did receive antimicrobial medications (P = .5513). Antibiotic-resistant deep incisional SSI occurred in two of 31 dogs that did not receive antimicrobial medications and in 18 of 277 dogs that did receive antimicrobial medications (P = .9920). Body weight correlated with deep incisional SSI and resistant infections. Prolonged duration of surgery and anesthesia were associated with superficial incisional SSI, deep incisional SSI, and antibiotic resistance. Surgeons influenced deep incisional SSI.

CONCLUSION

Previously reported predisposing factors for infection were confirmed, but postoperative administration of antimicrobial medications was not protective against SSI nor did it predispose to antibiotic resistance in our clinical setting.

CLINICAL SIGNIFICANCE

This study does not provide evidence to support administration of prophylactic oral antimicrobial medications after unilateral TPLO.

Use of an amikacin-infused collagen sponge concurrent with implant removal for treatment of tibial plateau leveling osteotomy surgical site infection in 31 cases

OBJECTIVE

To report the use and long-term outcome of dogs with surgical site infection (SSI) after tibial plateau leveling osteotomy (TPO), treated with an amikacin-infused collagen sponge and implant removal.

STUDY DESIGN

Retrospective study.

ANIMALS

Thirty-one client-owned dogs.

METHODS

Medical records were reviewed for dogs with SSI after a TPLO that were treated with surgical implant removal and concurrent implantation of an amikacin-infused collagen sponge. Relevant clinical and surgical data were recorded. The TPLO implants were routinely removed; the surgical site was swabbed for culture. The sponge was aseptically infused with amikacin prior to implantation. Postprocedure examinations consisted of visual inspection of the incision by the surgeon and lameness scoring.

RESULTS

Thirty-one dogs met all inclusion criteria. Median follow-up time was 687 days. Short-term examination after implant removal and sponge implantation revealed uneventful incisional healing in 24 dogs. Six (19.4%) dogs exhibited inflamed incision sites a median of 4 days (range, 3-9) postoperatively that resolved without additional treatment. One (3.2%) dog required empirical antibiotic treatment 7 days postoperatively but was lost to long-term follow-up. Long-term follow-up examination revealed no clinical evidence of SSI recurrence and no lameness in the remaining 30 cases.

CONCLUSION

Surgical implant removal and implantation of an absorbable collagen sponge infused with amikacin alone was an effective treatment for postoperative TPLO SSI.

CLINICAL SIGNIFICANCE

This procedure had a 96.8% long-term resolution of SSI. It should be considered as a treatment option for TPLO SSI.

Manual polishing of 3D printed metals produced by laser powder bed fusion reduces biofilm formation

Certain 3D printed metals and surface finishes may be better suited for canine patient specific orthopedic implants on the basis of minimizing potential bacterial biofilm growth. Thirty disks each of titanium alloy, stainless steel, and cobalt chromium alloy were 3D printed via laser powder bed fusion. Fifteen disks of each metal were subsequently polished. After incubation with a robust biofilm-forming methicillin-resistant Staphylococcus pseudintermedius isolate, disks were rinsed and sonicated to collect biofilm bacteria. Serial dilutions were plated on blood agar, and colony forming units were counted log (ln) transformed for analysis of variance. Interference microscopy quantified surface roughness for comparison to biofilm growth. Scanning electron microscopy on both pre- and post-sonicated disks confirmed biofilm presence and subsequent removal, and visualized surface features on cleaned disks. Significantly more bacteria grew on rough versus polished metal preparations (p < 0.0001). Titanium alloy had more bacterial biofilm growth compared to cobalt chromium alloy (p = 0.0001) and stainless steel (p < 0.0001). There were no significant growth differences between cobalt chromium alloy and stainless steel (p = 0.4737). Relationships between biofilm growth and surface roughness varied: positive with the rough preparations and negative with the smooth. Polished preparations had increased variance in surface roughness compared to rough preparations, and within disk variance predominated over between disk variance for all preparations with the exception of rough cobalt chromium alloy and rough stainless steel. Using scanning electron microscopy, bacterial biofilms tended to form in crevices. Overall, manual polishing of 3D printed surfaces significantly reduced biofilm growth, with preparation-specific relationships between surface roughness and biofilm growth. These results suggest that metallic implants produced by laser powder bed fusion should be polished. Further research will elucidate the optimal surface roughness per preparation to reduce potential biofilm formation and implant associated infection.

Influence of fixation systems on complications after tibial plateau leveling osteotomy in dogs greater than 45.4 kilograms (100 lb)

OBJECTIVE

To determine the influence of 3 fixation systems on complications rate after tibial plateau leveling osteotomy (TPLO) in dogs >45.4 kg.

STUDY DESIGN

Retrospective case series.

SAMPLE POPULATION

Dogs (N = 287, 342 stifles) >45.4 kg with cranial cruciate ligament tear treated with TPLO.

METHODS

The medical records of dogs treated with TPLO were reviewed for fixation and postoperative complications, with a follow-up of at least 6 weeks. A random effects logistic regression model was used to evaluate the association between the type of TPLO fixation system and complications.

RESULTS

The fixation systems included a 3.5-mm broad TPLO plate alone (8P; 78.4%), a 3.5-mm broad TPLO plate with SOP (String of Pearls) plate (8AP; 14.9%), and a 3.5-mm standard TPLO plate (6P; 6.7%). Among the included stifles, 214 (62.6%) fixation systems were classified as locking, and 128 (37.4%) were classified as nonlocking. The fixation system was predictive of complications. The 8P had the lowest odds ratio for complication among the 3 fixation systems. Odds of developing complications were higher with the 8AP fixation system than with the 8P fixation system. Locking fixation eliminated the association between weight and complication rate.

CONCLUSION

Fixation of a TPLO with the 8AP increased the risk of complications compared with the 8P in this population of large dogs.

CLINICAL SIGNIFICANCE

Locking fixation of TPLO with a 3.5-mm broad TPLO plate alone should be considered in large dogs because it may reduce complications.

Locking compression plate stabilization of 20 distal radial and ulnar fractures in toy and miniature breed dogs

Objective: To evaluate retrospectively the effectiveness of the Locking Compression Plate® (LCP), in the form of either a straight or notched head T-plate, for the treatment of fractures of the distal radius and ulna in a series of 20 toy and miniature breed dogs.

Methods: The medical records of toy and miniature breed dogs (<6 kg), greater than six months of age, with fractures of the distal radius and ulna from two veterinary hospitals were reviewed. The inclusion criteria included: fractures of the distal 1/3 of the radius and ulna and repair with open reduction and internal fixation utilizing an LCP (straight or notched head T-plate).

Results: Twenty fractures (20 dogs) satisfied the inclusion criteria; eight straight and 12 notched head T-plates were used, either 2.0 mm (n = 13) or 2.4 mm (n = 7). Hybrid fixation was performed in all dogs in one or both fragments. Mean time to radiographic union was 6.9 ± 2.5 weeks (range: 4–12 weeks) in 18/20 dogs with radiographic follow-up. One complication was observed: infection that resolved with antibiotic medication and implant removal. No other major complications occurred by the time of last follow-up. In all cases (mean follow-up: 15 ± 7 months), the reported limb function as evaluated by the referring veterinarian or owner was excellent.

Clinical significance: The LCP, used as a hybrid construct for the treatment of distal radial and ulnar fractures was shown to yield excellent clinical results with both uncomplicated healing and excellent functional outcomes in this series of toy and miniature breed dogs.

Bi-institutional retrospective cohort study evaluating the incidence of osteosarcoma following tibial plateau levelling osteotomy (2000–2009)

Objectives: To evaluate the incidence and risk factors for occurrence of osteosarcoma (OSA) following tibial plateau levelling osteotomy (TPLO).

Methods: Medical records of client-owned dogs that underwent consecutive TPLO procedures at two institutions were retrospectively reviewed. Referring veterinarians and owners were contacted for follow-up. Each institutional cohort was assessed separately, and the incidence density rate and median time to occurrence of OSA at the TPLO site and at other sites were calculated. Marginal Cox regression was used to calculate hazard ratios and 95% confidence intervals for potential risk factors for occurrence of OSA.

Results: There were 472 CLINIC A (Colorado State University Veterinary Teaching Hospital) and 1992 CLINIC B (SAGE Centers for Veterinary Specialty and Emergency Care) TPLO cases with over one year of follow-up available. There were five and six dogs within the cohorts that developed OSA at the site of TPLO, and seven and 22 dogs that developed OSA at other anatomical sites, respectively. The incidence density rates of OSA at the TPLO site were 30.4 and 10.2 per 10,000 dog-years at risk, and other sites were 42.6 and 37.5 per 10,000 dog-years at risk. The median time to occurrence of OSA of TPLO site OSA was 4.6 and 4.4 years, which was longer than that of other site OSA of 2.9 and 3.4 years.

Clinical significance: There is a low incidence of OSA following TPLO surgery. The longer time to occurrence for TPLO site OSA is similar to that for fracture-associated sarcoma, and could indicate a similar underlying pathophysiology rather than spontaneous OSA occurrence.

Outcome following removal of TPLO implants with surgical site infection

Objective To evaluate the outcome of surgical site infection (SSI) associated with tibial plateau levelling osteotomy (TPLO) implants following treatment by medical management alone or implant removal with or without the administration of antibiotic medication.

Animals Ninety dogs (104 TPLO surgical procedures).

Methods Records of dogs that had undergone TPLO implant removal due to SSI were reviewed. Outcome following treatment with antibiotic medications without implant removal, and treatment with implant removal with and without the administration of antibiotic medications was evaluated.

Results Treatment of SSI with antibiotic medication alone failed in 88.9% (64/72) of the dogs. The clinical signs of SSI resolved in 94.9% (74/78) of the dogs treated with implant removal (with and without the administration of antibiotic medication postimplant removal). The effect of administration of antibiotic medication on outcome of treatment of the SSI by implant removal was not significant. The rate of SSI associated with the Synthes implant was higher than with the Slocum implant, but not the New Generation implant.

Conclusion Implant removal with or without the administration of antibiotic medication post-implant removal for treatment of TPLO SSI provided superior outcome compared to treatment with antibiotic medications without implant removal.

Clinical significance Implant removal should be considered for TPLO SSI that have not responded to appropriate medical management. Further investigation of the various TPLO implants and their effects on postoperative infection rate is warranted.

Complications of tibial plateau levelling osteotomy in dogs

The tibial plateau levelling osteotomy (TPLO) is one of the most common surgical procedures used to treat cranial cruciate ligament disease in dogs. Complications occurring during or after TPLO can range in severity from swelling and bruising to fracture and osteomyelitis. Ten to 34% of TPLO surgical procedures are reported to experience a complication and approximately two to four percent require revision surgery to address a complication. Although the risk factors for many complications have not been fully assessed, the best available evidence suggests that complications of TPLO can be reduced with increased surgeon experience, careful surgical planning, and accurate execution of the surgical procedure. Identification of known or suspected risk factors and intraoperative technical errors allow subsequent action to be taken that is aimed at decreasing postoperative morbidity. There is a need for prospective studies with consistent data reporting in order to fully reveal the incidence risk factors for complications associated with TPLO.

Prospective Randomized Clinical and Radiographic Evaluation of a Novel Bioabsorbable Biocomposite Tibial Tuberosity Advancement Cage Implant

OBJECTIVE

To evaluate the suitability of a novel bioabsorbable biocomposite cage (BC) implant for use in tibial tuberosity advancement (TTA) surgery in dogs with cranial cruciate ligament (CrCL) disease and to compare radiographic osteotomy healing scores and complications between groups that received either a BC or stainless steel cage (SSC).

STUDY DESIGN

Prospective randomized clinical study.

ANIMALS

Dogs with unilateral CrCL rupture (n=56).

METHODS

TTA was performed in 60 consecutive dogs using either a BC (30 dogs) or SSC (30 dogs). Patient parameters, 6 week and 6 month postoperative radiographic osteotomy healing scores, time elapsed to postoperative rechecks, and complications were compared between groups. Osteotomy healing was graded using a 5-point (0-4) scale. Data were analyzed using Wilcoxon Rank Sum tests and χ(2) tests with significance set at P<.05.

RESULTS

Fifty-six dogs (30 BC, 26 SSC) had complete medical and radiographic records at 6 months for inclusion in data analysis. Three complications occurred in the BC group (1 major, 2 minor) and 2 occurred in the SSC group (2 minor). There was no statistical difference in patient parameters, 6 week healing scores, or complications between BC and SSC groups. Healing scores at 6 months were significantly higher in the BC group (3.3 ± 0.52) compared to the SSC group (2.9 ± 0.69; P=.04).

CONCLUSION

Based on improved BC osteotomy healing scores 6 months after surgery with no significant differences in complications compared to SSC, BC TTA cages are a viable alternative to SSC.

Prospective surgical site infection surveillance in dogs

OBJECTIVE

To 1) describe the incidence of surgical site infections (SSI) in dogs undergoing surgery at the Ontario Veterinary College Health Sciences Centre; 2) describe and compare procedure-specific SSI rates; and 3) identify factors associated with development of SSI.

STUDY DESIGN

Prospective, cohort study

ANIMALS

Dogs (n = 846) undergoing surgery during 45 weeks (September 2010-July 2011).

METHODS

Follow-up telephone conversation with dog owners was performed 30 days postoperatively, with additional 1-year follow-up performed for cases with surgical implants. A standardized questionnaire was administered to detect and characterize SSI.

RESULTS

SSI were identified in 26 (3.0%) dogs; 11 (42%) were classified as superficial SSI, whereas 13 were deep, and 2 were organ/space. Of the confirmed SSI, only 17 (65%) were documented in the medical records. Hypotension (P = .011), class of surgery (P = .029), and use of an implant (P = .001) increased the risk of SSI. Microbial cultures were submitted for 19 cases (73%) and of those, 74% were staphylococci.

CONCLUSIONS

SSI can result in devastating consequences in dogs and understanding risk factors is critical to target prevention practices. Whereas some risk factors such as hypotension are modifiable, others such as class of surgery are not. When possible, active surveillance should be used as part of a hospital infection control program.

A pitfall on postoperative radiographs in dogs after tibial plateau leveling osteotomy

OBJECTIVE

To identify the cause of an occasional radiolucent line in the tibia on postoperative radiographs after tibial plateau leveling osteotomy (TPLO) in dogs.

STUDY DESIGN

Retrospective case series and ex vivo experiment.

SAMPLE POPULATION

Dogs (n = 80; 87 stifles) with cranial cruciate ligament (CCL) rupture that had TPLO; and 4 canine tibia specimens.

METHODS

Medical records (2007-2010) and radiographs of dogs that had TPLO were reviewed and examined for presence of a radiolucent line on postoperative radiographs. The TPLO procedure was reproduced ex vivo to determine the origin of this line by use of metallic wires to identify bone contours.

RESULTS

A curvilinear radiolucent line was visible in 14 (16%) tibias and was 5.4 times more likely to be visible with lateral misalignment of the tibial diaphysis relative to the plateau and 2.6 times more likely visible on caudocranial radiographs with the stifle in outward rotation. Fracture complication rate was higher in dogs with this radiolucent line (P = .02) and with lateral misalignment of the tibial diaphysis relative to the plateau (risk ratio, 3.8). The line could be reproduced ex vivo and caused by superimposition of the craniomedial border of osteotomy with the tibial plateau.

CONCLUSIONS

The radiolucent line was a spurious fracture line created by the medial margin of the tibial osteotomy and confounding factors such as tibial misalignment may explain the apparently associated higher complication rate.

Characterization of the biofilm forming ability of Staphylococcus pseudintermedius from dogs

Background

Staphylococcus pseudintermedius is an opportunistic pathogen of dogs and has emerged as a leading cause of skin, wound and surgical site infections worldwide. Methicillin resistance is common and clinical infections as a result of methicillin-resistant S. pseudintermedius (MRSP) pose a clinical challenge. In other staphylococci, biofilm formation has been shown to be a virulence factor for infection, however, it has received little attention in S. pseudintermedius. The objectives of this study were to evaluate the biofilm forming ability of clinical isolates of S. pseudintermedius obtained from dogs using phenotypic and genotypic techniques.

Results

96% (136/140) of S. pseudintermedius isolates were classified as strong or moderate biofilm producers, with the majority of isolates being able to produce biofilm. There was no difference in biofilm formation between MRSP and MSSP (p=0.8), amongst isolates from clinical infections compared with isolates obtained from colonized dogs (p=0.08), and between isolates from sequence type (ST) 71 and ST 68 (P=0.09). icaA was detected in 77.9% (109/140) of isolates and icaD was detected in 75.7% (106/140) of isolates. Scanning electron microscopic evaluation of S. pseudintermedius biofilm production revealed aggregates of cocci and irregularly produced extracellular polymeric matrix.

Conclusion

The majority of S. pseudintermedius isolates evaluated in this study were able to produce biofilm and this may be an important virulence factor in the rapid emergence of this bacterium in veterinary hospitals worldwide. Further study into the mechanisms of biofilm formation by S. pseudintermedius is warranted.