Summary Background Navicular disease in the horse often requires injection of the navicular bursa. We have developed an ultrasound‐guided, lateral needle approach to navicular bursocentesis, which avoids penetration of the deep digital flexor tendon (DDFT) and the need for radiographic control. Objectives To describe and evaluate the feasibility and efficacy of an ultrasound‐guided, lateral bursocentesis technique. Study design Cadaveric and in vivo experiments. Methods The navicular bursa in 62 cadaveric forelimbs of 31 horses and in both forelimbs of 26 live horses, positioned with the foot flexed in a navicular block, were submitted to lateral, ultrasound‐guided injection of 1.5 ml radiocontrast agent. Lateromedial radiographs were taken to locate the contrast. A second injection of 0.5 ml methylene blue was administered during needle withdrawal in cadaveric limbs to investigate the needle pathway during dissection. Results Contrast agent was successfully deposited in the navicular bursa in 104 of 114 (91%) limbs and in the navicular bursa alone in 89 of 114 (78%) limbs. Dissection showed no evidence of penetration of the DDFT in cadaver limbs. Failure to inject the navicular bursa was significantly associated with poor quality of the ultrasound image (P = 0.04) and resulted in aberrant injection of the distal interphalangeal joint in five of 114 (4%) limbs, the peribursal soft tissues in four of 114 (4%) limbs and the digital flexor tendon sheath in one of 114 (0.9%) limbs. Synovial fluid was observed at the needle hub in 58% of live horses. Main limitations It is unknown whether injection results obtained in the limbs of horses without disease can be extrapolated to horses with clinical disease of the podotrochlear apparatus. The localisation of contrast medium on radiographs may not accurately reflect the behaviour of local anaesthetic solution or therapeutic medications injected in the navicular bursa. Conclusions This lateral, ultrasound‐guided technique for injecting the navicular bursa is effective, does not penetrate the DDFT and avoids exposure of personnel to radiation.

Bone marrow lesions of the distal condyles of the third metacarpal bone are common and not always related to lameness in sports and pleasure horses AbstractThe metacarpophalangeal joint is a common site of pain in horses. Little information is available about bone marrow lesions in the distal condyles of the third metacarpal bone in sports and pleasure horses. Aims of this prospective, retrospective, observational study were to evaluate the prevalence of bone marrow lesions in the distal condyles of the third metacarpal bone, to describe their anatomic distribution and to correlate lesions with the presence of lameness and the level and type of activity. All sports and pleasure horses undergoing standing low-field MRI of the front fetlock region between 2009 and 2016 were included and divided into three lameness groups according to the results of diagnostic analgesia. Bone marrow lesions were analyzed and graded by one reader. Grades were compared between anatomical locations and between lameness groups.A total of 166 horses were sampled. The prevalence of bone marrow lesions was 76.5% (127/166).The dorsal aspects of the medial condyle (31%, 39/127) and of the sagittal ridge (28%, 36/127) were the most commonly affected locations. There was no significant difference between both forelimbs (lame limb and non-lame limb) of the same horse. Lesion severity was neither significantly associated with the lameness group nor with the type or level of activity. The prevalence of bone marrow lesions in the distal condyles of the third metacarpal bone is high in this population and the clinical significance is not always clear. Further studies are required to elucidate the clinical significance of this finding in sports and pleasure horses. K E Y W O R D Sequine, fetlock, magnetic resonance imaging, subchondral

Summary Avulsion of the proximal attachment of the proximal digital annular ligament (PDAL) was identified in five horses based on characteristic radiographic findings and supported by ultrasonographic examination in four horses. In two cases, PDAL avulsion was associated with acute onset lameness based on physical examination (both animals) and diagnostic analgesia (one animal), and was the only lesion identified. Both horses became sound after a period of rest. Radiographs repeated 11 years later in one animal showed minimal change in the appearance of the lesion. PDAL avulsion was associated with a substantial tear of the deep digital flexor tendon in another horse and in the remaining two cases PDAL avulsion was not associated with lameness. A dissection study found that the proximodistal extent of the proximal PDAL attachment, expressed as a proportion of the length of the proximal phalanx, was significantly (P = 0.011) greater in hindlimbs (11.48 ± 1.01%) compared with forelimbs (8.55 ± 1.06%). This finding may explain why hindlimbs appear at greater risk of PDAL avulsion. In conclusion, while PDAL avulsion can be a cause of acute lameness which, in uncomplicated cases, responds to rest, it can also be an incidental radiographic finding.

We report an unusual case of a young Quarter Horse with a large dental fracture fragment displaced into the maxillary sinus, leaving an oroantral communication that caused food impaction and metaplastic calcification in the sinus and facial deformation with cutaneous fistulation. Oral extraction of a remaining tooth fragment from its alveolus was succeeded by a maxillary sinusotomy for removal of the abnormal sinus contents. Since the oroantral fistula did not heal spontaneously following the placement of a silicone dental prosthesis, minimally invasive transbuccal and transnasal endoscopic approaches were used to encourage closure of the oroantral fistula by alveolar granulation. The clinical, diagnostic, and therapeutic features of this case may be helpful to clinicians when dealing with similar cases.