EQUINE VETERINARY EDUCATION / AE / july 2022


391


the published studies, endoscopy has a comparable outcome to through-and-through needle lavage.


Through-and-through needle lavage Through-and-through needle lavage is anecdotally a more cost-effective approach to treatment. Most cases will require general anaesthesia, although some can be carried out under standing sedation. The clinician does not need any specialised equipment or facilities, and only a basic level of training is required (Crosby et al., 2019). The advantages of this procedure may be favourable in certain cases, such as foals with acute sepsis and no osseous abnormalities (Watts, 2017), and financially restricted cases where other treatment options are not accessible. However, in many cases a lower volume of fluid is flushed through the synovial cavity, and the inability to directly visualise and assess the synovial cavity makes determining the prognosis more difficult.


Diagnostics Laboratory diagnostic results are used in conjunction with clinical judgement when diagnosing synovial sepsis. Additional techniques that assist the diagnosis include: confirming direct communication of a wound with a synovial cavity by distention with sterile saline (Findley et al., 2014; Isgren et al., 2020), positive bacteriological culture and/or visualisation of intracellular bacteria on cytological smears (Isgren et al., 2020), positive contrast radiography, the gross appearance of the synovial fluid including an increase in


turbidity (Duggan & Mair, 2019) and endoscopic/arthroscopic findings compatible with sepsis (Wereszka et al., 2007). Braake (2002) included cases that were diagnosed by clinical inspection to have synovial sepsis, and retrospective analysis of the cases showed the synovial cell count to range from 12–333 9 109/L and the percentage of PMNs to be 85%–99%. Troillet et al., (2020) also showed the synovial cell count to range from 21.9 to 220.3 9 109/L, PMN 73%–96% and TP 29.3– 61.6 g/L. Wright et al., (2003) showed the TNCC to range from <5to >100 9 109/L, TP 22–82 g/L and 75% had >80% of PMN. As shown in Table 1, a range of diagnostic inclusion values have been reported, including synovial TNCC ranging from ≥10 9 109/L to ≥20 9 109/L; in two studies, the percentage of PMNs in synovial fluid was >80%, and one study used a value of >90% PMN; TP in synovial fluid ranged from 20–40 g/L.


Application to clinical practice The comparison between outcomes, including survival to discharge and return to exercise, was highly variable in the studied literature. Yet, it should be recognised that many different synovial structures were included in these studies, and the prognosis for successful treatment is likely to vary depending on the specific structure involved. The three studies directly comparing the two surgical treatment techniques showed no significant difference in the outcome (Duggan & Mair, 2019; Troillet et al., 2020; Wereszka et al., 2007); however, the results should be interpreted with caution since the studies were not controlled and only included small numbers of patients. The authors suspect that there has been a generational shift towards favouring endoscopic lavage as a treatment technique for synovial sepsis, and the apparent advantages of endoscopic lavage are favoured by many clinicians. Further large-scale prospective, multi-centre studies examining the outcomes of treatments of septic synovitis in


specific synovial structures would be required to further inform the veterinary literature. A range of synovial fluid analysis inclusion criteria are demonstrated in the above studies, and it would be important to use standardised diagnostic values for synovial sepsis in future studies. It is important to also be aware that the synovial fluid analysis values can vary, depending on the nature and duration of the underlying injury causing sepsis; for example, the synovial fluid TNCC can be significantly higher if the injury is caused by Prunus spinosa (blackthorn) (Ashton, 2018). It is beyond the scope of this article, however, it would be valuable in future studies to evaluate the financial implications of the different treatment methods, to further assess the effects of specificsynovial fluid analysis results on the prognosis and to document the long- term outcome of synovial sepsis affecting different synovial cavities.


Authors’ declarations of interest No conflicts of interest have been declared.


Ethical animal research Not applicable.


Source of funding No funding has been used for this publication.


Authorship


Both authors have been involved with the following: study design, study execution, data analysis and interpretation, preparation of the manuscript and final approval of the manuscript.


References


Ashton, N.M. (2018) Prospective study of blackthorn injury and synovitis in 35 horses. Equine Veterinary Education 32, 492–499.


Baxter, G.M. (2008) Diagnosis and management of wounds involving synovial structures. In: Equine Wound Management, 2nd edn. Eds: T.S. Stashak and C. Theoret. Elsevier, Edinburgh. pp 269–306.


Braake, F.T. (2002) Improved prognosis with immediate endoscopic approach of septic synovitis in the horse. Tijdschrift voor Diergeneeskunde 127, 444–449.


Crosby, D.E., Labens, R., Hughes, K.J., Nielsen, S. and Hilbert, B.J. (2019) Factors associated with survival and return to function following synovial infections in horses. Frontiers in Veterinary Science 6,1–9.


Duggan, M.J. and Mair, T.S. (2019) Comparison of outcomes following treatment of septic calcaneal bursitis by needle or burscopic lavage. A retrospective study in 29 horses. Equine Veterinary Education 33, 135–142.


Findley, J.A., Pinchbeck, G.L., Milner, P.I., Bladon, B.M., Boswell, J., Mair, T.S. et al. (2014) Outcome of horses with synovial structure involvement following solar foot penetrations in four UK veterinary hospitals: 95 cases. Equine Veterinary Journal 46, 352–357.


Hackett, E.S. (2015) Penetrating wounds of synovial structures. In: Robinson’s Current Therapy in Equine Medicine. Eds: K.A. Sprayberry and N.E. Robinson, Elsevier, Amsterdam. pp 31–34.


Isgren, C.M., Salem, S.E., Singer, E.R., Wylie, C.E., Lipreri, G., Graham, R.J.T.Y. et al. (2020) A multi-centre cohort study investigating the outcome of synovial contamination or sepsis of the calcaneal bursae in horses treated by endoscopic lavage and debridement. Equine Veterinary Journal 52, 404–410.


© 2021 EVJ Ltd


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88