Arthroscopic removal of palmar intermediate carpal bone fracture fragments in four horses using a transthecal approach through the carpal flexor tendon sheath.

OBJECTIVE: To describe the removal of palmar intermediate carpal bone (ICB) fracture fragments using a transthecal approach through the carpal flexor tendon sheath. STUDY DESIGN: Case series. ANIMALS: Four horses with fractures of the palmar aspect of the ICB. METHODS: Two horses were injured when falling and two during recovery from general anesthesia. Three horses underwent MRI to supplement conventional imaging. Three horses had concurrent fractures of the radial and/or accessory carpal bones. Conventional proximolateral carpal sheath arthroscope and instrument portals were used, supplemented with a medial instrument portal through the carpal flexor retinaculum to access the palmar carpal ligament. Optimized dissection through the latter was facilitated by needle guidance and radiography. The fragment was dissected from the soft tissue attachments and the palmar ICB fragments retrieved through the carpal sheath in all horses. Surgery time was 85 to 142 min. RESULTS: Limitations of this technique include a long surgery time and the potential for hemorrhage to impair visibility during surgery. All four horses were discharged 3 to 8 days postoperatively. Three horses returned to full athletic work within 9 months postoperatively and one horse was euthanized due to persistent lameness. CONCLUSION: A tenoscopic transthecal carpal flexor tendon sheath approach provides access for removal of palmar ICB fracture fragments but should be viewed as an advanced arthroscopic procedure. CLINICAL SIGNIFICANCE: A transthecal approach through the carpal flexor tendon sheath offers an alternative technique for removal of palmar ICB fracture fragments.

Bovine congenital erythropoietic protoporphyria in a crossbred limousin heifer in Ireland.

An unusual case of an 11-month-old, black Limousin-cross heifer, with an 8-month history of episodic seizures and photosensitisation, was referred by a veterinary practitioner to the Farm Animal Section of the UCD Veterinary Hospital, School of Veterinary Medicine, University College Dublin, Ireland, in August 2014. Following an investigation, a diagnosis of Bovine Congenital Erythropoietic Protoporphyria (BCEPP) was made. To the authors' knowledge this is the first report of such a case in Ireland. BCEPP should be considered as a differential diagnosis in young animals displaying periodic seizures and/or photosensitisation.

Presence and size of synovial masses within the navicular bursa correlate well between magnetic resonance imaging and bursoscopy and have a guarded prognosis.

BACKGROUND: Focal hyperintense lesions within the navicular bursa emanating from the dorsal border of the deep digital flexor tendon (DDFT) can be recognised on T1-weighted magnetic resonance images (MRI) and have been attributed to lameness in horses. Removal of these lesions, also referred to as synovial masses, by navicular bursoscopy is currently recommended. OBJECTIVES: To investigate the correlation between MRI and navicular bursoscopic findings. It is hypothesised that the prognosis following surgery is proportional to the size of the DDFT lesion. STUDY DESIGN: Retrospective analysis of clinical records. METHODS: Horses undergoing standing low-field MRI and navicular bursoscopy with >1 year follow-up were included. A grading system was developed to classify the size of synovial mass(es) and lesion(s) of the DDFT on MRI and at surgery. Generalised estimating equations were used to evaluate the association between MRI findings and surgery and between outcome and severity of the tendon injury. RESULTS: Fifty-nine horses presenting over a 15-year period (2006-2021) fulfilled inclusion criteria. Ninety navicular bursae were examined both on MRI and endoscopically. There was strong correlation between the size of synovial masses and tendon lesions on MRI and bursoscopy (p < 0.001, OR: 25.61, 95% CI 8.71-75.29 and p < 0.001, OR: 7.34, 95% CI 2.70-19.92, respectively). Size of tendon lesion and synovial mass had no impact on prognosis (p = 0.3, OR: 1, 95% CI 1-1 and p = 0.1, OR: 1, 95% CI 1-1, respectively), which was guarded (30.5% return to previous level of exercise). MAIN LIMITATIONS: Performance data for conservatively treated horses with MRI-detected synovial masses was not considered, nor was the effect of navicular bursal effusion. Horses were not randomly assigned to treatment protocols. CONCLUSION: There is good correlation between MRI and bursoscopic findings of DDFT lesions and synovial masses within the navicular bursa, with no false positives. Size of the synovial masses and DDFT lesions does not influence prognosis following navicular bursoscopy.

Outcome following repair of 63 sagittal fractures of the proximal phalanx in UK Thoroughbreds using either a triangular or linear screw configuration.

BACKGROUND: A triangular screw configuration has been suggested as preferable for repair of sagittal fractures of the proximal phalanx. OBJECTIVE: To assess the outcome of a triangular screw construct for repair of incomplete and complete minimally displaced proximal phalanx fractures under standing sedation in a population of Thoroughbred racehorses, compared with a cohort repaired using a linear screw configuration. STUDY DESIGN: Retrospective cohort study. METHODS: Medical records and radiographs were accessed to garner clinical data. Date of return to racing was determined from www.racingpost.com. Survival data were compared using log-rank test. RESULTS: Sixty-two horses with one horse having two separate fractures. Fifty-four fractures were repaired using triangular screw configuration, 10 with a linear screw configuration. 81% (43/53) of horses with triangular repair returned to racing at a median of 289 days (161-482 days), 70% (7/10) horses with linear screws returned to racing at a median of 351 days (230-815 days). MAIN LIMITATIONS: A limited number of horses underwent conventional (linear) screw placement. CONCLUSION: A triangular screw configuration placed in the standing sedated horse is an effective way to repair incomplete and complete minimally displaced proximal phalanx fractures. The rate of return to racing was excellent with a low rate of complications.

Sagittal plane slab fractures of the third carpal bone in 45 racing Thoroughbred horses.

BACKGROUND: Sagittal plane slab fractures of the third carpal bone are a recognised injury in the racehorse. Currently no published data exist for the UK Thoroughbred racehorse population. OBJECTIVES: To document return to racing following sagittal slab fracture of the third carpal bone in a UK-based racehorse population, and to compare conservative and surgical management. STUDY DESIGN: Single centre retrospective study. METHODS: Computerised medical and racing records were searched over a 15-year period for Thoroughbred racehorses with a simple sagittal slab fracture of the third carpal bone. Horses with comminuted fractures and short incomplete linear lucencies were excluded. Time from intervention to next race was recorded. Success rates were compared by Fisher's Exact Test and Mann-Whitney U Test. RESULTS: Forty-seven horses, with 49 fractures met the inclusion criteria. Overall, 27 horses raced following injury (60%). Median time to first start was 251 days (115-600, IQR 109). Fifteen horses with 16 fractures were managed conservatively. Seven horses (47%) raced, 115-508 days following injury (median 240 days, IQR 306). Thirty horses underwent surgery; this involved placement of a single 3.5-mm lag screw under arthroscopic guidance. Twenty horses (67%) raced again 145-600 days following surgery (median 264 days, IQR 102). A higher proportion of horses managed surgically improved their Racing Post Rating (RPR) following injury (14/20), compared with those managed conservatively (1/7, P = .02). MAIN LIMITATIONS: The numbers of horses are small, particularly for those managed conservatively. Treatment was not randomly allocated, and as such several horses which underwent conservative management were subsequently retired for breeding. CONCLUSIONS: This case series indicates that both arthroscopic repair and conservative management of sagittal slab fractures of the third carpal bone allows horses to successfully return to training and racing.

An alternative arthroscopic approach to the caudal pouches of the equine lateral femorotibial joint.

BACKGROUND: Current arthroscopic approaches to the caudal pouches of the lateral femorotibial joint are challenging and risk iatrogenic nerve and cartilage injury. OBJECTIVE: Describe an alternative arthroscopic approach to the caudal pouches of the lateral femorotibial joint in the horse and report intra-articular abnormalities observed during diagnostic stifle arthroscopy of these pouches. STUDY DESIGN: Descriptive cadaver anatomical and clinical study. METHODS: An approach to the caudal pouches of the lateral femorotibial joint was developed during clinical surgery using an arthroscopic portal in the popliteal tunnel of the femorotibial joint. Relevant anatomy of the lateral femorotibial joint was reviewed and the arthroscopic landmarks validated on 19 cadaver limbs. The procedure was then incorporated as part of routine inspection of 38 joints in 33 horses. RESULTS: Entry and examination of both pouches of the caudal lateral femorotibial joint was consistently achieved using an arthroscopic portal immediately cranial to the lateral collateral ligament in both cadaver and clinical limbs, with no adverse effects noted in the latter. Contrary to published descriptions, the division of the pouches was principally formed by a meniscopopliteal septum derived from the joint capsule in all cases, rather than the popliteus muscle and tendon as previously described. Abnormalities were detected in five cases. The finding of bilateral tearing within the popliteus muscle may represent a previously unrecognised arthroscopic condition. MAIN LIMITATION: Limited case numbers. CONCLUSION: An arthroscopic portal immediately cranial to the lateral collateral ligament permitted consistent entry into the popliteal tunnel and both pouches of the caudal lateral femorotibial joint.