Re: Rear breakdowns (727 Views)
Posted by:
sighthound (IP Logged)
Date: May 22, 2006 03:32PM
Caveat - not a practicing equine vet. Horses carry more weight on the forehand than rear. Brief lit search found a couple of interesting things, apologize in advance TGJB if too long or inappropriate to board content or current discussion:
Characterisation of the type and location of fractures of the third metacarpal/metatarsal condyles in 135 horses in central Kentucky (1986- 1994).
Equine Vet J 31[4]:304-8 1999 Jul - Zekas LJ, Bramlage LR, Embertson RM, Hance SR Rood and Riddle Equine Hospital, Lexington, Kentucky 40580-2070, USA.
The objective of this retrospective study was to provide a detailed description of the characteristics of condylar fractures represented in a population of 135 horses who sustained 145 fractures. Records and radiographic studies were examined. Fifty-nine percent of the horses were male and the majority Thoroughbreds. The distribution of fractures was 37% incomplete-nondisplaced, 30% complete-nondisplaced and 32% complete-displaced. *** The right front was more likely to sustain a complete-displaced fracture, whereas the left front was more likely to sustain an incomplete-nondisplaced fracture. Forelimbs (81%) and lateral condyles (85%) were more likely to be involved. Contrary to previous studies, the right forelimb was slightly more often involved than the left. Fractures tended to involve the middle portion of the condyle (59%). The mean length of all fractures was 75+/-3.8 mm. Axial fractures and medial condyle fractures tended to be longer. Fifteen percent of the fractures had definitive articular comminution. Ninety- five percent of fractures with articular comminution were associated with complete fractures. When fractures entered the middle area of the condyle, 23% had articular comminution. Eight of the fractures spiralled, all involved forelimbs. Concurrent lesions included proximal phalanx chip fractures, sesamoid fractures, sesamoiditis, proximal phalanx fractures, 'splint' bone periostitis and ligamentous injuries. The complete description of the fractures in this group of horses allows us better to define the condylar fracture, compare these fractures to previous studies and establish new data for use in defining prognosis.
High-speed exercise history and catastrophic racing fracture in thoroughbreds.
Am J Vet Res 57[11]:1549-55 1996 Nov Estberg L ; Stover SM ; Gardner IA ; Drake CM ; Johnson B ; Ardans A OBJECTIVE: To investigate the relation between several racing speed history characteristics and risk of fatal skeletal injury (FSI) in racing Thoroughbreds. ANIMALS: 64 Thoroughbreds euthanatized during a 9-month period in 1991 at a California racemeet because of a catastrophic fracture incurred while racing (cases), identified retrospectively. For each race in which an FSI occurred, 1 control horse was randomly selected from the noncatastrophically injured participants. PROCEDURE: Racing and officially timed workout histories were obtained for each horse. Several history characteristics were calculated to summarize racing career patterns and high-speed exercise schedules prior to date of injury and included age at first race, proportion of career spent laid up, average duration of laid up periods, average lifetime racing frequency, time from last lay up to date of injury, and total and rate of distance accumulated 1 to 6 months prior to date of injury. History characteristics associated with FSI were screened by paired t-test and studied in detail, using conditional logistic regression. *** RESULTS: High total and high average daily rates of exercise distance accumulation within a 2-month period were associated with higher risks for FSI during racing, yet career patterns, such as age at first race or total proportion of career spent laid up, were not found to be associated with risk for FSI. A horse that had accumulated a total of 35 furlongs of race and timed-work distance in 2 months, compared with a horse with 25 furlongs accumulated, had an estimated 3.9-fold increase in risk for racing-related FSI (95% confidence interval = 2.1, 7.1). A horse that had accumulated race and timed-work furlongs at an average rate of 0.6 furlong/d within a 2-month period, compared with a horse with an average of 0.5 furlong/d, had an estimated 1.8-fold increase in risk for racing-related FSI (95% confidence interval = 1.4, 2.6). CONCLUSIONS AND CLINICAL RELEVANCE: Thoroughbred racehorses that either accumulate large total high-speed distances or rapidly accumulate high-speed distances within a 2-month period may be at increased risk for FSI during racing.
Horseshoe characteristics as possible risk factors for fatal musculoskeletal injury of thoroughbred racehorses. Am J Vet Res 57[8]:1147-52 1996 Aug Kane AJ ; Stover SM ; Gardner IA ; Case JT ; Johnson BJ ; Read DH ; Ardans AA OBJECTIVE: To evaluate selected shoe characteristics as risk factors for fatal musculoskeletal injury (FMI) and specifically for suspensory apparatus failure (SAF) and cannon bone condylar fracture (CDY) of Thoroughbred racehorses in California. DESIGN: Case-control study. ANIMALS: Thoroughbred racehorses (n = 201) that died of were euthanatized at California racetracks between August 1992 and July 1994. PROCEDURE: Shoe characteristics were compared between case horses affected by FMI (155), SAF (79), and CDY (41) and control horses that died for reasons unrelated to the appendicular musculoskeletal system (non-FMI; 46). Multivariable logistic regression was used to estimate odds ratios for FMI, SAF, and CDY. RESULTS: Toe grabs were identified as possible risk factors for FMI, SAF, and CDY. The odds of FMI, SAF, and CDY were 1.8, 6.5, and 7.0, respectively, times greater for horses shod with low toe grabs than for horses shod without toe grabs on front shoes. Horses shod with regular toe grabs on front shoes had odds 3.5, 15.6, and 17.1 times greater (P < 0.05) for FMI, SAF, and CDY, respectively, compared with horses shod without toe grabs. The odds of horses shod with rim shoes were a third (P < 0.05) of those shod without rim shoes for either FMI or SAF. The apparent association between toe grab type and CDY may, in part, be attributable to concurrent SAF and CDY injuries in many horses. *** CLINICAL RELEVANCE: Avoiding the use of toe grabs should decrease the incidence of FMI, especially SAF, in Thoroughbred racehorses. The use of rim shoes that are more consistent with natural hoof shape may decrease injury risk.