Post operative synovial sepsis following endoscopic surgery: Increased risk associated with the carpal sheath

The overall rate of sepsis following endoscopic surgery of synovial structures has not previously been documented. Clinical observation has led to the conjecture that tendon sheaths, in particular the carpal flexor tendon sheath, are more prone to post operative synovial sepsis than other synovial structures.

To document and investigate the rate of post operative synovial sepsis following elective endoscopic surgery.

Retrospective case series.

The medical records of horses that underwent arthroscopy, tenoscopy or bursoscopy at Donnington Grove Veterinary Surgery between January 1999 and July 2012 were reviewed. The signalment, anatomical structure involved, use of electrosurgery, tourniquet or motorised resector, presence of a fracture, whether surgery was performed with the horse standing or under general anaesthesia and the number of structures examined were recorded. Multivariable logistic regression was used to test the association between the selected variables and synovial sepsis. Odds ratios (OR) and 95% confidence intervals (CI) were calculated. Level of significance was P<0.05.

There were 1670 horses that underwent endoscopic surgery of 3159 synovial structures: 2517 joints, 583 tendon sheaths and 59 bursae. There were 16 cases of post operative sepsis in 16 horses; therefore, the infection rate was one per 100 horses or 5 per 1000 procedures. Carpal sheath tenoscopy was associated with an OR of developing post operative synovial sepsis of 14.9 (95% CI 4.8-45.9, P<0.001) compared to other synovial structures. Tendon sheath endoscopy had an OR of developing post operative synovial sepsis of 5.21 (95% CI 1.24-21.91, P<0.02) compared to other synovial structures.

Surgeons should be aware that tendon sheaths and the carpal sheath in particular appear to have higher odds of developing sepsis following endoscopic surgery.