Meta-Analysis of Clinical Factors Affecting Synovial Structure Infections and Prognosis

Equine heel bulb lacerations: 62 cases (2004–2018)

OBJECTIVE

To characterize clinical findings and outcomes for horses with heel bulb lacerations.

ANIMALS

Medical records of a teaching hospital were reviewed to identify horses treated for heel bulb lacerations between February 2004 and October 2018. Long-term outcome was assessed by telephone communication with owners. Results were analyzed to determine association with clinical outcome.

RESULTS

31 mares and 31 geldings of various ages, breeds, and uses were evaluated. Thirty-six horses had a wound of 0 to 2 days’ duration, and 17 horses had a wound of > 2 days’ duration. Horses with a wound duration of < 2 days had a significantly greater likelihood of a higher outcome score (P = .025; OR = 7.08; 95% CI = 1.28% to 39.08%). Synovial communication with the wound was confirmed in 21 of 62 (33.9%) horses. One synovial structure was involved in 17 horses, and > 1 synovial structure was involved in 4 horses. Fifty-nine horses survived to discharge, and follow-up information was available for 18 (30.5%) horses. Of the horses available for follow-up, 78% returned to the previous level of work (14/18). Degree of lameness at presentation, degree of wound contamination, treatment prior to presentation, treatment with foot casting, and involvement of synovial structures were not found to be significantly associated with clinical outcome.

CLINICAL RELEVANCE

Results suggest that horses with heel bulb lacerations have a good prognosis for survival and a favorable prognosis for return to work. Clinical application of additional findings needs further investigation before clinical relevance can be ascertained.

A scoping review of the current evidence on treatment and outcomes following synovial sepsis

BACKGROUND

Synovial sepsis is a frequent cause of morbidity and mortality in horses. Despite advances in diagnostics and treatments, persistent infection or chronic lameness can occur.

OBJECTIVES

To perform a scoping review to identify and evaluate the current evidence on the factors implicated in the success of treatment for synovial sepsis.

STUDY DESIGN

Joanna Briggs Institute scoping review.

METHODS

A protocol was registered, and a systematic literature search was performed on CAB abstracts, Medline, Scopus and Embase. Inclusion and exclusion criteria were developed and studies systematically reviewed against this. Studies relating to factors affecting treatment success following synovial sepsis were retained and data was extracted on study method, population characteristics and factors significantly associated with treatment outcome.

RESULTS

In total, 2338 studies were identified, and 61 were included to full paper analysis. Eight papers reported significant factors, identifying 15 risk factors associated with two measurements of outcome, either survival and/or return to athletic function. The 15 factors were identified and categorised into pre-, intra- and post-operative factors. Risk factors that were identified included the number or type of synovial structures involved, the presence of pannus, tendon and bone pathology, and the use of systemic antimicrobials. There were many discrepancies in inclusion criteria of cases of synovial sepsis as well as measurement and description of outcome variables.

MAIN LIMITATIONS

Non-English language studies or conference proceedings were not included. Only small numbers of papers had similar findings.

CONCLUSIONS

Standardisation of inclusion criteria is essential to enable comparisons and analysis between studies on synovial sepsis. Future studies should use methodologies to reduce bias including multicentre and multinational studies, prospective study design and robust statistical modelling.

A Descriptive Study of the Clinical Presentation, Management, and Outcome of Horses with Acute Soft Tissue Trauma of the Tarsus and the Association with Synovial Involvement

Simple Summary

The hock is commonly involved in traumatic injuries in horses and due to the large number of synovial structures located in the region, this frequently results in synovial infection which is a major and potentially life-threatening complication in horses. The aim of this retrospective study was to describe the clinical presentation, diagnostic procedures, management, and outcome of cases with acute soft tissue trauma to the hock and to identify the clinical features that were associated with synovial infection in these cases. This study found that increased synovial effusion, severe lameness on admission, and the persistence of lameness as well as certain wound locations were more commonly associated with a diagnosis of synovial infection. Advanced diagnostic modalities such as radiographs, ultrasonography, and measurements of inflammatory markers aided in establishing the correct diagnosis. The duration of systemic antimicrobial treatment was shorter than previously reported and many cases received local antimicrobial treatment at the site of injury, which may have improved its efficacy. At the time of discharge, while lameness was still present in some cases, the overall survival was excellent. This study describes the clinical features and treatment of these commonly encountered injuries, and this knowledge may benefit clinicians in the future.

Abstract

The tarsus is one of the most common areas of traumatic injury with associated synovial involvement (SI) in horses. The aim of this retrospective study was to describe the clinical presentation, diagnostic procedures, management (emphasizing the type, duration, and route of antimicrobial administration), and outcome of cases with acute soft tissue trauma to the tarsal region. The presenting clinical features, the results of diagnostic modalities, and the initial response to therapy were assessed for their usefulness to predict SI. Medical records of 72 cases were included and SI was diagnosed in 34 cases (47.2%). Increased synovial effusion, lameness on admission (OR = 4.1; 95%CI 1.0–16.4), persistent lameness (OR = 5.7; 95%CI 1.8–17.9), increased blood SAA values (≥200 mg/L) from initial to second measurement (OR = 4.3; 95%CI 1.2–15.5), and wound location on the plantar/plantarolateral/plantaromedial compared to the lateral aspect of the tarsus (OR = 7.0; 95%CI 1.6–30.9) were associated with SI. Radiographs, ultrasonography, and the use of pressure testing when a wound was present proved to be useful in correctly diagnosing SI. The median duration of systemic antimicrobial administration was 8 (IQR: 5 to 9) days and most horses received local antimicrobial therapy. This study highlights several relevant clinical features and their association with SI and emphasizes the usefulness of local antimicrobial therapy in these cases.

Detection of synovial sepsis in horses using enzymes as biomarker

Background

Synovial sepsis is a commonly occurring, potentially career‐ending or even life‐threatening orthopaedic emergency. Diagnosis of synovial sepsis is currently primarily based on synovial fluid analysis, which often leaves diagnostic ambiguity due to overlap of clinicopathological parameters between septic and aseptic inflammatory synovitis.

Objectives

To evaluate the reliability of lysozyme (LYS), myeloperoxidase (MPO) and elastase (ELT) as biomarkers for synovial sepsis in horses using a photometric assay to measure increased enzyme activity.

Study design

Prospective, single‐blinded, analytical, clinical study.

Methods

Equine synovial samples were assigned to one of three groups: (1) healthy controls (n = 10), (2) aseptic (n = 27) and (3) septic synovitis (n = 30). The enzyme activity assays (LYS, MPO and ELT) were compared with standard synovial fluid parameters and broad‐range bacterial 16S rDNA PCR.

Results

LYS and MPO activities were significantly different between septic synovial samples, and both aseptic and control samples (P < .001, LYS: confidence interval [CI]: 2.25‐3.41, resp., 2.21‐3.8, MPO: CI 0.752‐1.6, resp., 0.639‐1.81). LYS achieved a 100% sensitivity and 100% specificity in differentiating between septic and aseptic (cut‐off value 751.4) or control (cut‐off: 484.6) samples (P < .001). MPO reached 93.33% sensitivity, 100% specificity for distinguishing septic from control (cut‐off value: 0.1254) synovial samples and 93.33% sensitivity, 81.48% specificity for discriminating between septic and aseptic (cut‐off value: 0.1305) synovial samples (P < .001). ELT activity could not be measured in any synovial sample. Both the LYS and the MPO measurements showed a highly significant correlation with PCR (LYS r = .79, MPO r = .69), synovial leukocyte count (LYS r = .752, MPO r = .571), % neutrophils (LYS r = .751, MPO r = 0.663) and each other (r = .744, all P < .001).

Main limitations

Variation in horses’ signalment, affected synovial structures and synovial fluid freezing times may have affected the discriminative power of this study.

Conclusions

Increased MPO and LYS activities allow reliable, rapid diagnosis of synovial sepsis with high sensitivity and specificity.

Factors Associated With Survival and Return to Function Following Synovial Infections in Horses

Synovial infections (SI) are common in horses of all ages and can be associated with high rates of morbidity and mortality. Identifying factors influencing survival and return to function may be useful for management of affected individuals and determination of prognosis. The objectives of this study were to identify factors associated with survival and return to function of horses and foals with SI presented to an equine hospital. This study is a retrospective case series. Data were collected from medical records of all horses with SI that were presented to a single equine hospital between April 1st, 2008 and May 1st, 2017. Long–term follow up was obtained by a semi-structured telephone questionnaire of clinical outcomes and analysis of online race records. Univariate models were created using generalized linear and linear mixed models to assess factors associated with outcomes. Multivariable models were created using generalized linear and linear mixed models to determine factors significantly associated with outcomes. Of 186 horses presented with SI, 161/186 (86.6%) were treated and 145/161 (90.1%) survived to discharge. The majority of joints were treated with synovial lavage (93.8%). One hundred and twenty horses were included in the return to function analysis and 79 (65%) returned to function. Increasing number of days of treatment with systemic antimicrobials was associated with increased likelihood of survival for each horse (OR 1.15, 95% CI 1.04−1.27, P = 0.025) and when considering each individual synovial structure (OR 1.11, 95% CI 1.04−1.17, P = 0.004). Horses treated with doxycycline were less likely to return to function (OR 0.39, 95% CI 0.19−0.8, P = 0.031). The overall rate of survival of horses treated with SI is good. The likelihood of return to function is lower than for survival. The findings of this study, combined with relevant antimicrobial stewardship practices, can be used as a part of evidence-based decision-making when veterinarians are treating horses with SI.