Frequency distributions of 174 fractures of the distal condyles of the third metacarpal and metatarsal bones in 167 Thoroughbred racehorses (1999–2009)

Reasons for performing study: Although fractures of the metacarpal and metatarsal condyles are the most common long‐bone fractures of Thoroughbred horses in training, limited data on variations in morphology and incidence have been published. Additionally, grouped analyses of previous studies from the UK and USA would permit comparison between study groups and the creation of a substantial pool of international data. Methods: Retrospective analysis of case records of horses with fractures of the distal condyles of third metacarpal/metatarsal bones seen over the last 10 years at Newmarket Equine Hospital. The current series was compared with a prior series from the UK; pooled analyses of these, and series from the USA were also compared. Results: One hundred and seventy‐four fractures were identified in 167 racehorses. The current series contained a significantly lower proportion of medial condylar fractures than in a similar population 17 years earlier. Fractures that originated more abaxially tended to be shorter, and a significant proportion of lateral condylar fractures arose outside of the condylar groove. There was also some apparent seasonality of fractures of the lateral condyles in 2‐year‐old horses, but not so in older horses or those with medial condylar fractures. Conclusions and potential relevance: A substantial portion (approximately 50%) of fractures in the present series cannot be explained by unifying theories of aetiopathogenesis, which suggest that fractures usually arise within the condylar groove, as a focus of cumulative fatigue and failure of adaptation of bone. A separate aetiopathogenesis may be responsible for a proportion of condylar fractures encountered in racehorses, and further work is required to elucidate this. Changes in the number of medial condylar fractures encountered may reflect the introduction of artificial racing and training surfaces, and also may reflect changes in the age demographic of horses racing in the UK since the introduction of year‐round ‘all‐weather’ racing.     

Scapula stress fractures in Thoroughbred racehorses: Eight cases (1997–2006)

No case series exists in the literature describing scapula stress fractures. The purpose of this study was to review the clinical findings, diagnostic images and outcome of 8 horses diagnosed with scapula stress fractures. Scapula stress fractures were seen in Thoroughbred racehorses displaying acute moderate forelimb lameness. Nuclear scintigraphy identified the mid‐distal scapula spine and/or scapula supraspinous fossa as predilection sites. Conservative management resulted in a good prognosis for return to racing, but stress fracture recurrence may be seen.     

Treatment of a femoral fracture with a titanium locking compression plate distal femur (LCP‐DF) in a young donkey

A closed complete mid‐diaphyseal spiral fracture of the left femur in a one‐year‐old donkey was treated with a 4.5 mm titanium locking compression plate distal femur (LCP‐DF)¹. This plate was originally manufactured for human orthopaedics, primarily for femoral osteosynthesis. The LCP‐DF¹ has a distal head plate that was advantageous in this case because the distal fragment was smaller. Post operative radiographs showed optimal femoral reconstruction and a callus was present 3 weeks after surgery. The donkey was sound at the walk and trot 2 months after surgery. Radiographs taken 5 months after surgery showed stable implants and complete healing without complications.     

Catastrophic biaxial proximal sesamoid bone fractures in UK Thoroughbred races (1999–2004): Horse characteristics and racing history

Reason for performing study: Catastrophic biaxial proximal sesamoid bone fractures (PSBF) have not yet been described in detail in the UK racing population. Objectives: To determine the incidence and relative risk (RR) of PSBF in different types of racing in the UK; and to describe horse‐level characteristics and racing histories of horses sustaining these injuries. Methods: Distal limbs were collected from all racehorses suffering catastrophic fractures during racing at all 59 racecourses in the UK, in a prospective study from February 1999 to December 2004. Post mortem investigation identified the anatomical location and type of fracture. Horse, racing history, race and racecourse details were obtained. Characteristics of the horses that sustained PSBF were described. The incidence and RR of PSBF in the different types of racing in the UK were calculated. Results: Thirty‐one horses suffered PSBF during the study period. The incidence of PSBF in all types of race was 0.63 per 10,000 starts (31/494,744). The incidence was highest in flat races on all weather surfaces (1.63 per 10,000 starts: 12/73,467; RR = 4.4 when compared to turf flat racing). Affected horses had an average age of 5.6 years and had started a mean of 28 races at the time of fracture. Conclusion and potential relevance: There is a strong association between type of racing surface and PSBF. Horses competing in flat races on all weather surfaces have an increased risk of PSBF. These fractures appear to happen in experienced horses with several starts, with few fractures occurring within the first season of racing. Further research should focus on identification of underlying pathology of these fractures. Epidemiological studies aimed at the identification of risk factors for PSBF in the UK racing population would require a large number of cases acquired over many years given the relatively low incidence of PSBF.