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lavage of the ISB under general anaesthetic was recommended as the most appropriate treatment option, however, it was declined for economic reasons. No significant improvement was noted following 72 h of antimicrobial treatment and repeat clinical examination identified a painful response to deep palpation of the biceps tendon. Repeat ultrasonographic examination identified persistent distention of the ISB with distension of the ITB also noted. Fluid within the ITB was hypoechoic. Synovial fluid of moderate turbidity and decreased viscosity was obtained from the ITB under ultrasonographic guidance (Schneeweiss et al. 2012) and submitted for cytology and culture. The nucleated cell count was 54.2 x 109 cells/ml. Standing lavage of both bursae was attempted following needle placement as described (Whitcomb et al. 2006). Through and through lavage of the ITB was achieved with 1 l of lactated Ringer’s solution (LRS) but standing lavage of the ISB was not possible. Conservative management was continued for a further 36 h. Staphylococcus intermedius was cultured from the ITB fluid
sample. The antimicrobial treatment was changed to enrofloxacin (5 mg/kg bwt i.v. s.i.d.) based on the sensitivity pattern. Over the next 5 days, comfort levels deteriorated further
with the horse becoming nonweightbearing (grade 5/5: AAEP). Due to the failure of conservative management permission was granted for endoscopic examination and lavage of both synovial structures under general anaesthesia.
Surgical treatment
The horse was placed in left lateral recumbency with the affected limb uppermost and supported horizontally at chest height. Synovial fluid retrieved from the ITB prior to surgery had a nucleated cell count of 66.8 x 109 cells/ml and subsequently returned a positive culture for Staphyloccus intermedius. The ITB was approached via a skin portal made with a No.
11 blade over the craniolateral margin of the humerus, approximately 3 cm proximal to the deltoid tuberosity (Adams and Turner 1999; McIlwraith et al. 2005). Using a conical obturator, the arthroscopic cannula was directed axially and proximally through the brachiocephalicus muscle and between the cranial humerus and biceps tendon entering the ITB. Exploration showed free floating fibrin and pannus adhered to the biceps tendon. An instrument portal was created proximal to the greater tubercle of the humerus, using an 18 gauge 4 cm needle as a guide and used to probe the lateral aspect of the intertubercular eminence and lateral tubercle, which were found to be healthy. Fibrin and pannus were removed using rongeurs revealing only minor irritation to the underlying epitenon. The bursa was lavaged with a total of 10 l of LRS. The bursa was medicated with 250 mg of enrofloxacin (Baytril 10%)1 and the portals closed with single interrupted sutures using 2-0 PDS. Prior to examination of the ISB, the arthroscope and
instruments including rongeurs and curettes were cleaned and subjected to cold sterilisation (Cidex)2. The ISB was distended with 10 ml of LRS under ultrasonographic guidance (18 gauge x 4 cm needle) under the caudal border of the infraspinatus tendon 4 cm distal to the greater tubercle (Whitcomb et al. 2006). A stab incision was created with a No. 11 blade in the skin and fascia. The arthroscopic cannula with blunt obturator was placed in the incision and advanced beneath the infraspinatus tendon aiming towards the middle of the ipsilateral shoulder joint, thus entering the ISB. Exploration
© 2015 EVJ Ltd IST
IST GT
Fig 1: Infraspinatus tendon (IST) curving over the caudal part of the greater tubercle (GT).
GT
Fig 2: Same view as Figure 1 with rongeurs introduced from a proximal portal. The instrument can navigate but range of motion is restricted by the pull of the infraspinatus tendon (IST).
revealed similar findings to the ITB with pannus adhering to the infraspinatus tendon, greater amounts of free fibrin (Fig 1) and a yellow-red discolouration of the synovial fluid. A needle was placed into the bursa 3 cm proximal to the stab incision following the caudal edge of the infraspinatus tendon and an instrument portal created in that location. Close portal placement hindered free movement of the instruments but was necessary due to the size limitations of this particular synovial structure. Fibrin and pannus were removed using rongeurs, revealing no visible damage to the infraspinatus tendon (Fig 2). Raising the foot higher than the patient’s shoulder reduced the passive tension on the infraspinatus tendon allowing better mobility of the instruments. A lesion of fibrillated, discoloured fibrocartilage was observed on the caudal aspect of the greater tubercle but access for curettage was limited. After thorough lavage using 6l of LRS, 150 mg of enrofloxacin was instilled into the bursa and the portals closed in similar fashion to the ITB. A povidone iodine
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