The use of small (2.7 mm) screws for arthroscopically guided repair of carpal chip fractures.

REASONS FOR PERFORMING THE STUDY: Removal of large chip fractures of the carpal bones and the osteochondral deficits that result, have been associated with a worse prognosis than removal of small fragments in similar locations. HYPOTHESIS: Reducing the articular defects by repair of large osteochondral fragments may have advantages over removal. METHODS: Horses with osteochondral chip fractures that were of sufficient size and infrastructure to be repaired with small (2.7 mm diameter) AO/ASIF cortex screws were identified and repair effected by arthroscopically guided internal fixation. RESULTS: Thirty-three horses underwent surgery to repair 35 fractures of the dorsodistal radial carpal bone (n = 25), the dorsal margin of the radial facet of the third carpal bone (n = 9) and the intermediate facet of the distal radius (n = 1). There were no surgical complications and fractures healed satisfactorily in 26 of 28 horses and 23 horses returned to racing performance. CONCLUSION: Arthroscopically guided repair of carpal chip fractures with small diameter cortex screws is technically feasible and experiences with 33 cases suggest that this may have advantages over fragment removal in managing such cases. POTENTIAL RELEVANCE: Surgeons treating horses with large chip fractures of the carpal bones should consider arthroscopically guided internal fixation as an alternative to removal.

Arthroscopic treatment of fractures of the lateral malleolus of the tibia: 26 cases.

REASONS FOR PERFORMING THE STUDY: A minimally invasive arthroscopic technique for removal of fractures of the lateral malleolus of the tibia is considered to be beneficial but data to this effect are required. HYPOTHESIS: Arthroscopic removal of fractures of the lateral malleolus of the tibia is technically feasible, provides a comprehensive evaluation of the tarsocrural joint and enables removal of remote comminuted fragments and disrupted short collateral ligaments. The technique is associated with low patient morbidity, requires only short periods of hospitalisation and affords a good prognosis to affected horses. METHODS: The case records of all horses that underwent arthroscopic removal of a fractured lateral malleolus of the tibia, admitted to a referral hospital, were evaluated retrospectively. Follow-up information was obtained from race records and by telephone questionnaire. RESULTS: Fractures were successfully removed arthroscopically in all cases following dissection from the short lateral collateral ligaments. Significant post operative complications occurred in only one horse. All other horses recovered well from surgery and of 22 horses with long-term follow-up, 18 returned to their previous use. CONCLUSION: Arthroscopic removal of fractures of the lateral malleolus of the tibia is technically demanding, but can be performed with minimal complications and with low patient morbidity and short periods of hospitalisation. The majority of horses are able to successfully return to work following the procedure. POTENTIAL RELEVANCE: The advantages of arthroscopic removal compared to removal via arthrotomy make this the technique of choice for treatment of fractures of the lateral malleolus of the tibia.

Equine embryonic stem-like cells and mesenchymal stromal cells have different survival rates and migration patterns following their injection into damaged superficial digital flexor tendon.

REASONS FOR PERFORMING STUDY: Injury to the superficial digital flexor tendon (SDFT) is common in racing and sport horses and poor tendon regeneration leads to high reinjury rates. Autologous mesenchymal stromal cells (MSCs) are being used clinically to improve tendon regeneration but they have some practical limitations. Embryonic stem cells (ESCs) may overcome these limitations but their fate following injection into the damaged SDFT is unknown. OBJECTIVE: To inject MSCs and ESCs into distinct areas of damage in the SDFT and monitor their survival over a 3 month period. METHODS: MSCs and ESCs expressing different reporter genes were injected into separate sites of mechanically induced damage in SDFTs. Cell survival and distribution were examined post mortem after 10, 30, 60 and 90 days and host immune responses determined. RESULTS: Neither MSCs nor ESCs produced signs of cell-mediated immune response or tumour formation. ESC survival was high and numbers were maintained at a constant level over 90 days. ESCs were present at all sites of damage. In contrast, MSCs showed <5% survival at 10 days and numbers declined over the course of the experiment. MSCs were detected only at the site into which they were injected. CONCLUSIONS: ESCs survived in greater numbers than MSCs in the damaged tendon and did not induce an immune response, or form tumours at the injection sites in the 90 day time period studied. ESCs also demonstrated an ability to migrate to other areas of damage within the same tendon, whereas MSCs did not. POTENTIAL RELEVANCE: ESCs can be used allogeneically, therefore providing a possible 'off the shelf' source of cells for therapeutic use which overcomes the practical limitations of autologous MSCs. Furthermore, MSCs and ESCs have different survival rates and migration patterns in the damaged tendon, suggesting that they may produce different functional effects. This may have clinical relevance to treating tendon injuries in the horse.

Radiographic and arthroscopic features of third carpal bone slab fractures and their impact on racing performance following arthroscopic repair in a population of racing Thoroughbreds in the UK.

BACKGROUND: Slab fractures of the third carpal bone (C3) are a common injury of Thoroughbred racehorses. Results of arthroscopically guided repair have not been reported since the initial description of the technique in 1986. Additionally, fracture details and racing outcomes in a population of Thoroughbreds racing under UK jurisdiction have not previously been described. OBJECTIVES: To report the frequency distribution of C3 slab fractures and to determine the impact on racing performance following arthroscopically guided repair in a population of Thoroughbred racehorses. STUDY DESIGN: Retrospective case series. METHODS: Case records of Thoroughbred racehorses undergoing arthroscopically guided repair of C3 slab fractures at Newmarket Equine Hospital between 2006 and 2015 were retrieved. Radiographs and arthroscopic studies were reviewed. The effect of demography and fracture morphology on racing outcome was evaluated. RESULTS: C3 slab fractures occurred most commonly through the radial facet in a frontal plane (45/71 63.4%). Comminution was identified during arthroscopy in 42/71 (59.2%) fractures and occurred most frequently at the palmar margin of the fracture. Forty-one out of 65 horses (63.1%) raced at least once post-operatively. Females were less likely to return to racing compared to males (P<0.001). Horses that had raced before injury were more likely (OR 4.4, 95% CI 1.4-13.5, P = 0.01) to race after injury compared to horses that were unraced at the time of injury. After injury horses had a small but significant reduction in racing performance. MAIN LIMITATIONS: The series is a preselected population of Thoroughbred racehorses which referring veterinary surgeons considered potential candidates for surgical repair. CONCLUSION: Fracture configurations can be identified radiographically but is not a reliable predictor of comminution or other intra-articular lesions. Arthroscopy not only directs repair but also identifies and facilitates management of concurrent lesions. The results reported should assist in formulating appropriate prognoses for Thoroughbred horses racing in the UK.

Gastric and small intestinal ileus as a cause of acute colic in the post parturient mare.

REASONS FOR PERFORMING STUDY: Ileus (functional obstruction of aboral gastrointestinal transit) is an uncommon cause of gastrointestinal dysfunction and colic in the horse. A number of specific conditions have been previously reported in association with ileus. This report describes the recognition of primary gastric and small intestinal ileus of undetermined cause in a series of post parturient mares. OBJECTIVES: To describe the clinical features, treatment and outcome of a series of episodes of primary gastric and small intestinal ileus. METHODS: A retrospective study was performed of colic episodes seen in an equine practice in Newmarket, UK over a 6 year period (2002-2007). RESULTS: Seventeen episodes of gastric and small intestinal ileus were identified, which occurred in 15 horses. All episodes occurred in post parturient mares. No previously reported cause of ileus was identified in any of the episodes. Fifteen of the 17 episodes received medical treatment (medical support and nasogastric decompression) and, in addition, surgical decompression was performed in 9 episodes. Two mares were subjected to euthanasia before treatment due to the presence of gastric rupture and the remaining 13 mares survived with a follow-up period of at least 10 months. Two mares suffered a further episode of gastric and small intestinal ileus, one 4 days and the other 2 years after the initial episode. CONCLUSIONS: Gastric and small intestinal ileus of, as yet, unknown aetiology appears to be a potential cause of acute colic in the post parturient mare. The outcome following treatment by decompression is good.

Monitoring the fate of autologous and allogeneic mesenchymal progenitor cells injected into the superficial digital flexor tendon of horses: preliminary study.

Autologous mesenchymal progenitor cells (MPCs) purified from bone marrow aspirates are being used in the treatment of superficial digital flexor tendon (SDFT) injuries in the horse with promising results. In this study the fate of autologous and allogeneic MPCs following injection into the SDFT was monitored by stable transfection of MPCs with green fluorescent protein (GFP). Small lesions were created manually in one forelimb SDFT of 2 horses and injected with autologous MPCs, allogeneic MPCs or bone marrow supernatant alone. Post mortem examinations performed after 10 or 34 days revealed GFP labelled cells located mainly within injected lesions, but with a small proportion integrated into the crimp pattern of adjacent healthy areas of tendon. Furthermore, there was no visible cell mediated immune response to allogeneic MPCs in either of the host horses.

Frequency distribution of osteochondral fragmentation of the dorsoproximal articular surface of the proximal phalanx in racing Thoroughbreds in the UK.

BACKGROUND: Osteochondral fragmentation of the dorsoproximal margin of the proximal phalanx is commonly recognised in racing Thoroughbreds. Frequency distribution has been documented in racing Thoroughbreds and Quarter Horses in the USA and in European Warmbloods but no data have been published from the UK. Concurrent intra-articular soft tissue lesions and radiographic accuracy of fragment distribution in racing Thoroughbreds have not previously been reported. OBJECTIVES: To document frequency distribution of dorsoproximal fragmentation of the proximal phalanx in a UK population of racing Thoroughbreds and to compare this with published data. To document concurrent intra-articular lesions identified arthroscopically and radiographic accuracy of fragment distribution. STUDY DESIGN: A retrospective single centre-based, observational study. METHODS: Surgical reports and radiographs of all racing Thoroughbreds that underwent arthroscopic surgery for removal of fragmentation from the dorsoproximal margin of the proximal phalanx at Newmarket Equine Hospital between 2011 and 2015 were reviewed. RESULTS: Two hundred and forty-two (85.8%) horses were in or being prepared for flat racing. Osteochondral fragmentation of the dorsoproximal aspect of the proximal phalanx was present in 428 fetlock joints of 282 horses, consisting of 194 (45.3%) left and 188 (43.9%) right metacarpophalangeal joints, and 20 (4.7%) left and 26 (6.1%) right metatarsophalangeal joints. Fragmentation was located dorsomedially in 316 (73.8%), dorsolaterally in 32 (7.5%) and biaxially in 80 (18.7%) joints. Concurrent soft tissue lesions were identified in 168 (39.3%) joints. Radiographic evidence of fragmentation was visible in 320 joints (74.8%). MAIN LIMITATIONS: Limited numbers preclude conclusions with respect to yearlings and horses in jump race training. CONCLUSION: Dorsoproximal fragmentation of the proximal phalanx occurred most frequently medially and in the forelimbs. Sidedness was not demonstrated. Although similar to previously reported data, variance in limb distribution is evident. Further research is required to determine whether concurrent intra-articular soft tissue lesions are aetiopathogenic or an additional result of the pathological changes leading to fragmentation. Fragmentation site was not always accurately identified radiographically. The Summary is available in Spanish - see Supporting information.

Endoscopic assessment and treatment of lesions of the deep digital flexor tendon in the navicular bursae of 20 lame horses.

REASONS FOR PERFORMING STUDY: Clinical lesions of the deep digital flexor tendon and navicular bone are being reported with increasing frequency. However, the role of direct visualisation by navicular bursoscopy in the diagnosis and management of such injuries has not been explored. HYPOTHESIS: Navicular bursoscopy: 1) corroborates information obtained from other, noninvasive imaging modalities; 2) allows direct visualisation of lesions unidentified by other diagnostic modalities; 3) provides further information on morphology of lesions; and 4) permits minimally invasive surgical access to lesions. METHODS: The case records of all horses that underwent diagnostic navicular bursoscopy for the investigation of lameness admitted to 2 referral clinics (the Royal Veterinary College and Reynolds House Referrals) were evaluated retrospectively. Follow-up information was obtained by telephone questionnaire. RESULTS: Twenty-three bursae were examined endoscopically in 20 horses. Tears of the deep digital flexor tendon were seen in all horses (22 bursae). In 8 bursae, cartilage lesions were also present and in one bursa this was the only abnormal finding. Computed tomography and low field magnetic resonance imaging predicted tendon lesions in most cases, but failed to identify cartilage damage. Greater than 6 month follow-up information was available for 15 animals of which 11 were sound and 9 had returned to preoperative levels of performance. CONCLUSION: Lameness localised to the foot may result from tears of the deep digital flexor tendon and/or navicular fibrocartilage loss. Navicular bursoscopy allows comprehensive evaluation of these changes and also permits appropriate lesion management. POTENTIAL RELEVANCE: The diagnostic information obtained from and therapeutic options offered by bursoscopy justify its use in horses with clinical findings localising lameness to the navicular bursa.

Parasagittal fractures of the proximal phalanx in Thoroughbred racehorses in the UK: Outcome of repaired fractures in 113 cases (2007-2011).

BACKGROUND: Thirty years have elapsed since the last published review of outcome following fracture of the proximal phalanx in Thoroughbred racehorses in the UK and contemporary results are needed to be able to advise of expected outcome. OBJECTIVES: Collect and analyse outcome data following repair of fractures of the proximal phalanx in Thoroughbred racehorses in the UK. STUDY DESIGN: Retrospective case series. METHODS: Case records of all Thoroughbred racehorses admitted to Newmarket Equine Hospital for evaluation of a parasagittal fracture of the proximal phalanx during a 5 years period were reviewed. Follow-up data regarding racing careers was collected for horses that underwent repair. Following exclusion of outliers, cases with incomplete data sets and comminuted fractures, mixed effect logistic regression was used to identify variables affecting returning to racing and odds ratios and confidence intervals calculated. RESULTS: Of 113 repaired cases, fracture configurations included short incomplete parasagittal (n = 12), long incomplete parasagittal (n = 86), complete parasagittal (n = 12) and comminuted (n = 3). A total of 54 (48%) cases raced after surgery. Horses that fractured at 2 years of age had increased odds of racing following surgery than those older than 2 years of age (OR 1.34; 95% CI 1.13-1.59, P = 0.002). Horses sustaining short incomplete parasagittal fractures had increased odds of racing following surgery compared with those with complete parasagittal fractures (OR 2.62; 95% CI 1.36-5.07, P = 0.006). No horses with comminuted fractures returned to racing. MAIN LIMITATIONS: Data are relevant only to Thoroughbred racehorses in the UK. CONCLUSIONS: Approximately half of the cases in this series raced following surgical repair. More 2-year-old horses raced following surgery, but this likely reflects horses, specifically older horses, passing out of training from unrelated factors. Fracture configuration affects odds of racing, which is relevant to owners when deciding on treatment.

Noninfected tenosynovitis of the digital flexor tendon sheath: a retrospective analysis of 76 cases.

REASONS FOR PERFORMING STUDY: Until recently, the pathogenesis of noninfected tenosynovitis of the digital flexor tendon sheath (DFTS) has been considered obscure. With the advent of tenoscopy some inciting causes have been described, but to date few cases with a precise diagnosis have been reported. HYPOTHESIS: Tenoscopic surgery enables accurate diagnosis and facilitates treatment of noninfected tenosynovitis of the DFTS. METHODS: The case records of all horses with noninfected tenosynovitis of the DFTS admitted to a referral clinic over a 7-year period were evaluated retrospectively. Follow-up information was obtained by telephone questionnaire. RESULTS: A total of 76 horses were referred; all were evaluated tenoscopically and 11 of these subsequently were explored by open surgical techniques. The most common diagnoses were marginal tears of the deep digital flexor tendon (DDFT) (n = 44) and tears of the manica flexoria (MF) (n = 23). Greater than 6 months' follow-up information was available for 61 animals, of which 68% were sound and 54% returned to preoperative levels of performance. Sheath distension was eliminated in 33% and improved in 69% of horses. Marginal tears of the DDFT, marked preoperative distension and open surgical repair of deep digital flexor lesions were associated with reduced levels of post operative performance: Marginal tears were associated with post operative lameness and long tears with a reduced performance level compared with short tears. Marginal tears of the deep digital flexor tendon, marked preoperative distension and increasing duration of clinical signs also were associated with lack of improvement in distension following surgery. CONCLUSION: Tenosynovitis of the DFTS may result from tears in the deep or superficial digital flexor tendons, manica flexoria or other structures with synovial communication. To date, these can be identified confidently only by tenoscopy, which also permits appropriate lesion management. POTENTIAL RELEVANCE: The diagnostic information obtained from and therapeutic options offered by tenoscopy justify its early use in cases of noninfected tenosynovitis of the DFTS.

Equine hepatic disease: the effect of patient- and case-specific variables on risk and prognosis.

REASONS FOR PERFORMING STUDY: Liver disease is fairly common in horses and, although previous literature suggests that fatality rates are high, impressions gained from current clinical practice suggest that this is no longer the case. OBJECTIVES: A case-control study was undertaken in 2 hospitals to investigate whether age, gender or breed type predisposed horses to developing hepatic disease, with the additional aim of determining whether these factors and disease category had any effect on outcome. METHODS: Eighty-eight cases were identified by review of computerised archives at 2 hospitals. Three cases admitted immediately before and after the cases were used as controls. Multivariant models were developed to explore the relationship between age, breed type and gender and the development of liver disease, and within the clinical cases, to identify whether any of these factors or specific forms of liver disease were associated with fatality rate. RESULTS: Ponies were more likely to develop hepatic disease than light riding horses, but neither age nor gender were significant risk factors. Overall, the fatality rate was fairly low; horses with unclassified hepatopathies had the lowest fatality rate and those with cholangiohepatitis, pyrrolizidine alkaloid toxicity and chronic active hepatitis had significantly higher fatality rates in comparison. However, age, breed type and gender had no detectable effect on outcome. CONCLUSIONS AND POTENTIAL RELEVANCE: Such data could be of particular value to equine practitioners, as the cases were drawn from both primary and referral practice, and were all seen within the last 5 years.

Development and application of a scoring system for prognostic evaluation of equine liver biopsies.

REASONS FOR PERFORMING STUDY: The study was designed to investigate the prognostic value of liver biopsy during investigation of cases of suspected liver disease in mature horses. HYPOTHESIS: That liver biopsy is the most prognostically useful technique in common usage in the investigation of suspected liver disease. METHODS: This study examined the prognostic value of liver biopsy during the investigation of suspected liver disease in 73 mature horses. Histopathological variables comprising fibrosis, irreversible cytopathology, inflammatory infiltration, haemosiderin accumulation and biliary hyperplasia were found to be significant predictors of nonsurvival and were used to formulate a weighted biopsy score representing a prognostically useful broad comparative index of histopathological severity. Minimum and maximum possible scores were 0 and 14 points, respectively. RESULTS: Retrospective application of the biopsy scoring system to the study population indicated that horses with scores of 0 or 1 were equally likely to survive to 6 months with a combined mortality of 4%. Horses with biopsy scores between 2 and 6 had a combined mortality of 33% and were at a 12-fold increased risk of nonsurvival within 6 months (hazard ratio = 12.04, 95% CI 134-107.81, P = 0.026) compared to horses with a biopsy score of 0. Horses with biopsy scores between 7 and 14 had a combined mortality of 86% and were at a 46-fold increased risk of nonsurvival (hazard ratio = 46.01, 95% CI 5.92-357.5, P < 0.001) compared to horses with biopsy score 0. CONCLUSIONS: Application of the biopsy scoring system to histopathological findings in liver biopsy specimens was very useful in predicting survival of cases of suspected liver disease. POTENTIAL RELEVANCE: Application of the findings in this study may not be directly applicable to other case populations. However, liver biopsy appears to be the most valuable prognostic technique employed during the investigation of suspected cases of liver disease in mature horses.

Retrospective analysis of historical, clinical, ultrasonographic, serum biochemical and haematological data in prognostic evaluation of equine liver disease.

REASONS FOR PERFORMING STUDY: Results of noninvasive tests of liver disease do not always correlate with the degree of hepatic disease nor outcome of the case. OBJECTIVE: To investigate the prognostic value of data collected using noninvasive tests during the investigation of cases of suspected liver disease in mature horses. HYPOTHESIS: Much of the data gathered during the investigation of suspected hepatopathy cases offers little prognostic guidance and interpretation of such data can be misleading. METHODS: The results from a range of common and noninvasive diagnostic techniques applied in 116 mature horses with suspected liver disease, were assessed for their ability to predict survival within a 6 month period. RESULTS: A significantly poorer prognosis was found in association with clinical signs suggestive of liver disease, presence of hepatic encephalopathy, ultrasonographic abnormalities, increased serum globulins, increased total bile acids (TBA), increased alkaline phosphatase (AP), increased gamma-glutamyl transferase (gammaGT), erythrocytosis, leucocytosis, low serum albumin and low serum urea. Additional significant novel findings of interest included an association between increased plasma fibrinogen and low serum creatinine concentrations with nonsurvival in cases of liver disease, an association between raised serum concentrations of AP and gammaGT with biliary hyperplasia and also an association between hepatic fibrosis, haemosiderosis and biliary hyperplasia with ultrasonographically detected hepatic abnormalities. CONCLUSIONS: The most useful noninvasive prognostic test in cases of suspected liver disease in mature horses is the severity of clinical signs. Other data may be of some limited prognostic value. POTENTIAL RELEVANCE: Application of the findings in this study may not be directly applicable to other case populations. However, the findings should at least be considered when prognosis is based on similar criteria.

Endoscopic surgery in the treatment of contaminated and infected synovial cavities.

REASONS FOR PERFORMING STUDY: Contamination and infection of synovial cavities are a common occurrence in clinical practice and, if inadequately treated, may have career or life threatening consequences for affected horses. HYPOTHESIS: The objectives in treating contamination and infection of joints, tendon sheaths and bursae are most effectively met by endoscopic surgery. METHODS: Over a 6 year period, cases of synovial contamination and infection admitted to a referral clinic were evaluated and treated endoscopically. The horses received local and systemic antimicrobial drugs with minimal nonsteroidal anti-inflammatory medication but no other medical or surgical treatment. All arthroscope and instrument portals and, whenever possible, all traumatic wounds were closed. Diagnostic information, endoscopic observations and results of treatment were evaluated retrospectively. RESULTS: A total of 140 affected animals were referred and 121 cases were treated endoscopically. These involved 70 joints, 29 tendon sheaths, 10 bursae and in 12 cases a combination of synovial cavities. The most common aetiologies were open wounds (n = 54) and self-sealing punctures (n = 41). Foreign material was identified endoscopically in 41 but predicted prior to surgery in only 6 cases. Osteochondral lesions were evident at surgery in 51 and recognised before surgery in 25 cases; 32 horses had intrathecal tendon or ligament defects. Follow-up information was obtained for 118 animals; 106 (90%) survived and 96 (81%) returned to their preoperative level of performance. The presence of osteitis/osteomyelitis, other osteochondral lesions and marked deposits of pannus were associated with nonsurvival. For those animals which survived, non-Thoroughbred horses, a combination of synovial structure involvement and regional i.v. antimicrobial administration were associated with reduced post operative performance. Marked pannus, regional i.v. antimicrobial administration and duration of systemic antimicrobial administration were associated with a group combining nonsurviving animals and those with reduced post operative performance. CONCLUSIONS: Endoscopic surgery makes a valuable contribution to the management of synovial contamination and infection. POTENTIAL RELEVANCE: The information obtained from and therapeutic options offered by endoscopy justify its early use in cases of synovial contamination and infection.

Are there radiologically identifiable prodromal changes in Thoroughbred racehorses with parasagittal fractures of the proximal phalanx?

REASONS FOR PERFORMING STUDY: Fractures of the proximal phalanx are generally considered to result from monotonic supraphysiological loads, but radiological observations from clinical cases suggest there may be a stress-related aetiology. OBJECTIVES: To determine whether there are radiologically identifiable prodromal changes in Thoroughbred racehorses with confirmed parasagittal fractures of the proximal phalanx. STUDY DESIGN: Retrospective cross-sectional study. METHODS: Case records and radiographs of Thoroughbred racehorses with parasagittal fractures of the proximal phalanx were analysed. Thickness of the subchondral bone plate was measured in fractured and contralateral limbs, and additional radiological features consistent with prodromal fracture pathology documented. RESULTS: The subchondral bone plate was significantly thicker in affected than in contralateral limbs. Evidence of additional prodromal fracture pathology was observed in 15/110 (14%) limbs with parasagittal fractures, and in 4% of contralateral limbs. CONCLUSIONS: The results of this study are not consistent with monotonic loading as a cause of fracture in at least a proportion of cases, but suggest a stress-related aetiology. Increased thickness of the subchondral bone plate may reflect (failed) adaptive changes that precede fracture. POTENTIAL RELEVANCE: Better understanding of the aetiology of fractures of the proximal phalanx may help develop strategies to reduce the risk of fracture.

Radiographic configuration and healing of 121 fractures of the proximal phalanx in 120 Thoroughbred racehorses (2007-2011).

REASONS FOR PERFORMING STUDY: Although fractures of the proximal phalanx are one of the most common long bone fractures of Thoroughbred horses in training, limited details on variations in morphology and radiological progression have been published. OBJECTIVES: To describe in detail the configuration of parasagittal fractures of the proximal phalanx in a group of Thoroughbred racehorses, to report fracture distribution within this group of horses and to document radiological progression of fracture healing in cases treated by internal fixation. STUDY DESIGN: Restrospective case series. METHODS: Case records and radiographs of Thoroughbred racehorses with parasagittal fractures of the proximal phalanx admitted to Newmarket Equine Hospital between 2007 and 2011 were analysed. RESULTS: One hundred and twenty-one fractures were identified in 120 Thoroughbred racehorses. Fractures were frequently more complex than was appreciated immediately following injury; a feature that has not been reported previously. There was seasonality of fractures in 2- and 3-year-old horses, but not in older horses. CONCLUSIONS AND POTENTIAL RELEVANCE: Fractures of the proximal phalanx may be more complex than recognised previously, although often their complexity cannot be identified radiographically immediately following injury. The seasonality observed in 2- and 3-year-old horses is most likely to be a consequence of the timing of the turf-racing season in the UK. The Summary is available in Chinese - see Supporting information.

Soft tissue injuries of the tarsocrural joint: a retrospective analysis of 30 cases evaluated arthroscopically.

REASONS FOR PERFORMING THE STUDY: Intra-articular soft tissue injuries of the equine tarsocrural joint have been poorly defined. METHODS: All horses that underwent arthroscopic surgery of a tarsocrural joint over a 10 year period were identified. Those with primary intra-articular soft tissue injuries were selected for inclusion and the cases evaluated retrospectively. RESULTS: Two hundred and eighty-one horses underwent tarsocrural joint arthroscopy during the study period, 30 of which met the inclusion criteria (30 joints). A combination of soft tissue lesions was more common than injury to a single structure. Injuries involved the joint capsule (n = 25), collateral ligaments (n = 20), dorsal plica (n = 8) and open communication between the tarsocrural joint and extensor bundle (n = 7). Following arthroscopic surgery and rehabilitation, 81% of horses were able to return to their previous function. CONCLUSION: Intra-articular soft tissue injuries of the tarsocrural joint may be associated with localising clinical signs of inflammation. This series represented 11% of the total number of arthroscopic procedures undertaken on that joint in a single referral hospital. Arthroscopic surgery allows accurate definition of the injuries and facilitates lesion management. Case outcome following arthroscopic debridement and a subsequent period of rehabilitation is favourable. POTENTIAL RELEVANCE: In lame horses with clinical signs localised to the tarsocrural joint, disrupted intra-articular soft tissues should be considered in the list of differential diagnoses. Attending clinicians should consider arthroscopic evaluation in cases where primary intra-articular soft tissue injuries are suspected to be causative.

Endoscopic evaluation of the navicular bursa: observations, treatment and outcome in 92 cases with identified pathology.

REASONS FOR PERFORMING STUDY: Diagnostic navicular bursoscopy has been described in limited cases. Review of greater numbers is needed to define its contribution to case management and prognostic values. OBJECTIVES: To report: 1) clinical, diagnostic and endoscopic findings in a series of cases, 2) surgical techniques and case outcomes and 3) prognostic values. The authors hypothesise: 1) lameness localising to the navicular bursa is commonly associated with dorsal border deep digital flexor tendon (DDFT) lesions, 2) endoscopy allows extent of injuries to be assessed and treated, 3) case outcome relates to severity of DDFT injury and 4) the technique is safe and associated with little morbidity. MATERIALS AND METHODS: All horses that underwent endoscopy of a forelimb navicular bursa for investigation of lameness were identified. Case files were reviewed and those with injuries within the bursa selected for further analysis. RESULTS: One-hundred-and-fourteen horses were identified. Ninety-two had injuries within the bursa and DDFT injuries were identified in 98% of bursae. Of those examined with magnetic resonance imaging (MRI), 56% had combination injuries involving the DDFT and navicular bone. Sixty-one percent of horses returned to work sound, 42% returned to previous performance. Horses with extensive tearing and combination injuries of the DDFT and navicular bone identified with MRI, had worse outcomes. CONCLUSIONS: Lameness localising to the navicular bursa is commonly associated with injuries to the dorsal border of the DDFT. Endoscopy permits identification and characterisation of injuries within the navicular bursa and enables lesion management. Outcome following debridement is related to severity of injury but overall is reasonable. POTENTIAL RELEVANCE: Horses with lameness localising to the navicular bursa may have tears of the DDFT. Bursoscopy is able to contribute diagnostic and prognostic information and debridement of lesions improves outcome compared to cases managed conservatively.