Racing performance after arthroscopic removal of apical sesamoid fracture fragments in Thoroughbred horses age > or = 2 years: 84 cases (1989-2002)

REASONS FOR PERFORMING STUDY: Studies have shown that surgical removal of apical fracture fragments in Standardbred racehorses carries the best prognosis for return to racing performance, but there are no reports involving mature Thoroughbred (TB) racehorses. OBJECTIVES: To describe the incidence of apical proximal sesamoid fractures in TB racehorses and determine probability and quality of racing performance after arthroscopic removal of such fractures in TB racehorses age > or = 2 years. METHODS: Medical records and pre- and post operative race records of TB racehorses age > or = 2 years that underwent arthroscopic surgery for removal of apical proximal sesamoid fracture fragments were reviewed. RESULTS: Sixty-four percent of fractures occurred in the hindlimbs and 36% in the forelimbs. Horses with forelimb fractures had a reduced probability of return to racing (67%) compared to those with hindlimb fractures (83%), but the majority (77%) of treated horses recovered to return to race post operatively. Horses with medial forelimb fractures raced at only a 47% rate; those with suspensory desmitis at 63%. Unlike Standardbreds, there was no difference in probability of racing post operatively between horses that had, and had not, raced preoperatively. CONCLUSIONS: Data show that arthroscopic removal of apical proximal sesamoid fracture fragments is successful at restoring ability to race in skeletally mature TB horses without evidence of severe suspensory ligament damage. Prognosis for return to racing is excellent (83%) in horses with hindlimb fractures and good (67%) in those with forelimb fractures. Medial fractures of the forelimb have the worst prognosis. POTENTIAL RELEVANCE: The determination of prognosis for differing sites in TB racehorses should increase knowledge of apical proximal sesamoid bone fractures and improve communication from veterinarian to owner, and trainer, on the potential for arthroscopic restoration of the ability to race.     

The effect of recurrent laryngeal neurectomy in conjunction with laryngoplasty and unilateral ventriculocordectomy in thoroughbred racehorses

OBJECTIVE: To investigate the effects of recurrent laryngeal neurectomy (RLN) in combination with laryngoplasty and ventriculocordectomy on the postoperative performance of Thoroughbred racehorses treated for grade III left laryngeal hemiparesis (LLH). STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Fifty-five Thoroughbred racehorses. METHODS: Medical records for Thoroughbred racehorses treated surgically by laryngoplasty and laser ventriculocordectomy with or without RLN between June 1993 and December 1996 were reviewed. Outcome was evaluated subjectively by assessment of performance obtained from telephone interviews with owners and trainers, and objectively by assessment of racing performance for 3 races before and after surgery using a performance index (PI). RESULTS: Fifty-five Thoroughbred racehorses with resting endoscopic grade III LLH were treated by laryngoplasty and ventriculocordectomy either with (39 horses) or without (16 horses) RLN. For RLN horses, respondents for 38 horses believed performance was improved in 19 horses, unchanged in 16 horses, and decreased in 3 horses. For horses without RLN, respondents for 9 horses reported that performance was improved in 5 horses, unchanged in 2 horses, and decreased in 2 horses. PI scores were improved in 18 RLN horses and in 6 horses without RLN; there was no statistical difference in outcome. CONCLUSIONS AND CLINICAL RELEVANCE: Use of RLN in combination with laryngoplasty and ventriculocordectomy for treatment of grade III LLH may not improve postoperative racing performance.     

Effect of ‘tongue tie’ use on racing performance of Thoroughbreds in the United Kingdom

Reasons for performing study: There is contradictory published evidence on the potential efficacy of ‘tongue ties’ (TTs) for treatment of intermittent dorsal displacement of the soft palate (DDSP) in racehorses. Objectives: To evaluate the effect of TTs on racing performance in Thoroughbred racehorses in the UK using a retrospective cohort study. Methods: Data on individual horses' lifetime racing performance and TT use were retrieved from the Racing Post Online Database. Exposed cases were horses that ran with a TT in randomly chosen race meetings on one of 60 randomly chosen dates from 2001–2003. Unexposed (control) horses were matched to each exposed horse. Various measures of racing performance were analysed both within and between exposed and unexposed groups. Subsets of exposed horses that ran for 3 or 5 consecutive starts wearing TTs and their matched controls were analysed separately to examine the effect of repeated TT use. Results: The inclusion criteria were fulfilled by 108 horses. The odds ratio for ‘improvement’ in race earnings between exposed and unexposed horses was 1.85 for horses that ran at least once with a TT, and 3.60 and 4.24, respectively, for horses that ran in 3 or 5 consecutive races wearing a TT. After instigation of TT use, horses that ran in 3 or 5 consecutive races wearing a TT had a significant increase in earnings when they ran wearing a TT compared to their pre‐TT races. Conclusions and potential relevance: The use of a TT appears to have a beneficial effect on racing performance in a selected population of Thoroughbred racehorses.     

Patterns of scintigraphic uptake in the fetlock joint of Thoroughbred racehorses and the effect of increased radiopharmaceutical uptake in the distal metacarpal/tarsal condyle on performance

Reasons for performing study: The effect of palmar osteochondral disease lesions on performance of Thoroughbred (TB) racehorses is unclear. There is a need to describe patterns of radiopharmaceutical uptake (IRU) in fetlock joints of TB racehorses and to evaluate post scintigraphy performance. Hypotheses: IRU in the metacarpal (MC) and metatarsal (MT) condyles is more common than IRU in the parasagittal grooves and is associated with poorer post diagnosis performance than controls. Methods: Location of IRU within the fetlock region was identified and graded subjectively in TB racehorses. Performance variables were determined from race records for horses with moderate/marked MC/MT condylar IRU (cases), other horses undergoing scintigraphy (scintigraphy controls) and age/sex matched controls from the last race in which a case participated (controls). Statistical analyses included quantile regression, Fisher's exact test, Kaplan‐Meier survival curves, log‐rank test and Cox regression. Results: Metacarpal/MT condylar IRU was identified in 103/220 horses with only 3/220 having parasagittal IRU. Moderate/marked IRU was identified in the MC and MT condylar regions in 62 and 39 horses, respectively, with palmaromedial and plantarolateral IRU most common. Fore‐ and hindlimb cases had fewer starts, reduced earnings (P<0.001) and reduced earnings/start than controls respectively. Cases were more likely to return to racing later than controls following a rest period. Cases were older than scintigraphy controls. Conclusions: In TB racehorses presenting for lameness MC/MT condylar IRU is the most common abnormality identified within the fetlock joint. Racehorses with moderate/marked condylar IRU have a shortened racing career, are less successful than age/sex matched controls and are older than other racehorses presented for scintigraphy. Potential relevance: Overload of the MC/MT condyles is a common and significant problem in TB racehorses that is readily identified with scintigraphy. Scintigraphy of horses that are lame or performing poorly is less useful for screening for potential condylar fractures.     

Racing Performance in 72 Racehorses Treated with Prosthetic Laryngoplasty for Laryngeal Hemiplegia

The purpose of this study was to compare racing performance before and after prosthetic laryngoplasty for treatment of laryngeal hemiplegia in inexperienced (horses without at least one start before surgery) and experienced (horses with at least one start before surgery) Thoroughbred and Quarter Horse racehorses. Medical records of 54 Thoroughbred and 18 Quarter Horse racehorses or horses intended for racing treated with prosthetic laryngoplasty and unilateral ventriculectomy for laryngeal hemiplegia were reviewed. Signalment, age at the time of surgery, resting endoscopic grade of laryngeal function, surgical procedure, and type of suture were recorded. Median performance index (PI), earnings, distance, and Beyer speed figure (BSF) per start for three races before and after surgery were compared, and factors associated with improved postsurgical performance were evaluated. Seventy-three percent of horses that had not raced before surgery and 84% of horses that competed in at least one race before surgery were able to return to racing after surgery. Fifty-nine percent and 27% of Thoroughbreds and Quarter Horses, respectively, were able to improve their PI after surgery. Sixty-two percent and 20% of Thoroughbreds and Quarter Horses, respectively, significantly increased their distance after surgery. Additionally, 61% and 66% of racehorses were able to increase their earnings and BSF after surgery, respectively. Horses treated with laryngoplasty and unilateral ventriculectomy have a good prognosis for return to racing. Inexperienced racehorses have a better prognosis for improvement after surgery than do experienced racehorses. Thoroughbred racehorses have a better success rate than Quarter Horse racehorses.     

Postoperative Race Performance is Not Correlated with Degree of Surgical Abduction After Laryngoplasty in National Hunt Thoroughbred Racehorses

Objectives— To (1) assess the degree of arytenoid cartilage abduction lost after laryngoplasty (LP) in Thoroughbred National Hunt racehorses and (2) to correlate postoperative racing performance with degree of arytenoid abduction after LP. Study Design— Case series. Animals— National Hunt Thoroughbred racehorses (n=68). Methods— Grade of postoperative arytenoid abduction for National Hunt racehorses that had LP with ventriculocordectomy was assessed at 1 day, 6 days, and 6 weeks after LP. Race records were analyzed to ascertain if there was correlation between the degree of arytenoid cartilage abduction and various measures of race performance (return to racing postoperatively, total earnings in 5 races immediately postoperatively, and lifetime number of starts postoperatively). Results— Median postoperative arytenoid abduction was grade 2 on day 1 but had decreased to grade 3 by 6 weeks. Horses with grades 1, 2, and 3 abduction 1 day after surgery had median losses of 1, 1, and 0.5 abduction grades, respectively, at 6 weeks. Horses with grade 1 abduction on day 1 were significantly more likely to lose abduction by day 6 after surgery than horses with grade 3 abduction on day 1. There was no statistically significant correlation between the postoperative grade of arytenoid abduction at any time point and earnings in 5 races after surgery, likelihood of racing postoperatively, or total number of lifetime race starts postoperatively. Conclusions— Horses with maximal (grade 1) surgical arytenoid abduction are significantly more likely to suffer postoperative loss of abduction than those with grade 3 abduction. Postoperative grade of abduction does not appear significantly correlated with markers of racing performance in National Hunt racehorses; however, very few horses with poor (grade 4 or 5) abduction were included and thus conclusions regarding racing performance in such horses cannot be drawn from this study. Clinical Relevance— Seemingly, most horses with grade 3 laryngeal abduction can race successfully and perhaps surgeons should not be disillusioned by the appearance of only moderate (grade 3) abduction in the long term after LP in racehorses.     

Efficacy of thermal cautery for intermittent dorsal displacement of the soft palate as compared to conservatively treated horses: Results from 78 treadmill diagnosed horses

Reasons for performing study: Previously, objective comparisons of surgical procedures to relieve dorsal displacement of the soft palate (DDSP) have been limited by the presumptive basis of the diagnostic measures applied. Objectives: To assess and compare the efficacy of thermal cautery surgery to conservatively treated controls in racehorses definitively diagnosed with idiopathic intermittent DDSP. Hypothesis: Both conservative and surgical treatments have a beneficial result on racing performance in racehorses affected with DDSP. Methods: Race records were obtained for Thoroughbred racehorses definitively diagnosed with DDSP using highspeed treadmill endoscopy. Racing performance was assessed based on prize money won. Results: Forty‐eight horses that underwent thermal cautery and 30 conservatively treated controls were included. Pretreatment earnings significantly decreased in the race immediately prior to diagnosis. A high proportion of previously raced horses returned to racing after both treatments (90–96%). Intrahorse comparison of earnings in 3 races pre‐ vs. post treatment showed that 53% of conservatively treated horses and 36% of the thermal cautery group had improved performance. Although the difference between these 2 groups may be interpreted as being clinically significant, it was not statistically significant. Conclusions and potential relevance: A higher percentage of conservatively treated controls had improved individual performance compared to horses treated with thermal cautery. Thermal cautery appears less effective than other previously published surgical treatments for DDSP. Comparison of the 2 treatment methods should be interpreted cautiously because treatments were not randomised, resulting in baseline variability between groups.     

Long-term study of partial arytenoidectomy with primary mucosal closure in 76 Thoroughbred racehorses (1992-2006)

REASON FOR PERFORMING STUDY: The effectiveness and best method to perform a partial arytenoidectomy in racehorses is unclear. This study was performed to evaluate the success of and complications that can occur after a unilateral partial arytenoidectomy with primary mucosal closure in Thoroughbred racehorses. HYPOTHESIS: Partial arytenoidectomy is an effective surgical procedure to return Thoroughbred racehorses, afflicted by arytenoid chondropathy or a failed laryngoplasty, to preoperative levels of performance. METHODS: Seventy-six Thoroughbred racehorses admitted to the New Bolton Centre between 1992 and 2006 were assessed. Information was obtained from the medical records about the horse, laryngeal abnormalities, surgery and other findings during hospitalisation. Racing information was evaluated relative to those independent variables by an analysis of variance with a level of significance of P<0.05. RESULTS: Arytenoid chondropathy was the presenting complaint in 54 horses and failed laryngoplasty in 22 horses. Thirteen horses (17%) underwent a second surgery for laser excision of intralaryngeal granulation tissue at the arytenoidectomy site. Seventy-three horses were discharged from the hospital and racing outcome was evaluated. Sixty horses (82%) raced after surgery and 46 horses (63%) raced 5 or more times after surgery. The median time from surgery to the first start was 6 months. The average earnings/start was not significantly different before and after surgery. There was no association between earnings after surgery and age, gender, location of lesion, type of lesion, duration of tracheal intubation or undergoing a second surgery. CONCLUSIONS AND POTENTIAL RELEVANCE: A Thoroughbred racehorse is likely to race after a unilateral partial arytenoidectomy with primary mucosal closure and return to a preoperative level of performance.     

Lag screw fixation of dorsal cortical stress fractures of the third metacarpal bone in 116 racehorses

Reasons for performing study: The effectiveness and best method to manage dorsal cortical stress fractures is not clear. This study was performed to evaluate the success of lag screw fixation of such fractures in a population of Thoroughbred racehorses. Hypothesis: Lag screw fixation of dorsal cortical stress fractures is an effective surgical procedure allowing racehorses to return to their preoperative level of performance. Methods: The records of 116 racehorses (103 Thoroughbreds) admitted to Equine Medical Centre, California between 1986 and 2008 were assessed. Information obtained from medical records included subject details, limb(s) affected, fracture configuration, length of screw used in repair and presence of concurrent surgical procedures performed. Racing performance was evaluated relative to these factors using Fisher's exact test and nonparametric methods with a level of significance of P<0.05. Results: Of 92 Thoroughbred horses, 83% raced preoperatively and 83% raced post operatively, with 63% having ≥5 starts. There was no statistically significant association between age, gender, limb affected, fracture configuration or presence of concurrent surgery and likelihood of racing post operatively or of having 5 or more starts. The mean earnings per start and the performance index for the 3 races following surgery were lower compared to the 3 races prior to surgery; however, 29 and 45% of horses either improved or did not change their earnings per start and performance index, respectively. Conclusions and potential relevance: Data show that lag screw fixation is successful at restoring ability to race in horses suffering from dorsal cortical stress fractures.     

An investigation of the relationship between race performance and superficial digital flexor tendonitis in the Thoroughbred racehorse

Reasons for performing study: There is limited information regarding the number of races and the period for evaluation of outcome which is critical for assessment of SDF tendonitis treatments. Objective: To evaluate the re‐injury rate and racing performance of Thoroughbred racehorses that sustain SDF tendonitis in relation to matched controls in terms of number of races post treatment and maximum racing performance ratings before and after injury. Study design: Clinical records and racing histories of 401 racehorses with a first occurrence of SDF tendonitis diagnosed by ultrasonography. Controls were of the same age, sex and were horses training in the same establishment at the time of injury as the case horses and where the trainer reported that the horse had not had a previous SDF tendon injury or treatment. Results: Eighty percent of both case and control horses returned to racing after the date of injury, and the re‐injury proportion within 3 years of treatment was 53%. The difference in Racing Post Rating_(max) (RPR_(max)) and the Racing Post Rating in the race immediately before the treatment date was significantly smaller in case horses (mean = 9.6 lbs; range = 0–75) compared to control horses (mean = 17.0 lbs; range = 0–79). No significant decrease in RPR_(max) was noted post injury. No difference between case and control horses was found for return to racing and racing 3 times, but control horses were significantly more likely to compete 5 races post treatment date than case horses. Conclusion and clinical relevance: Injury was associated with an individual's pre‐injury maximum performance level and return to racing and completion of 3 races are not useful indicator of the outcome of horses with SDF tendonitis. The assessment of the outcome of horses with an SDF injury in a population of racehorses using the number of races post injury requires a minimum of 5 races post injury to be a useful indicator. Further, a re‐injury proportion in a population of horses in training for 3 years post treatment.     

Management and assessment of prognosis after gastrocnemius disruption in Thoroughbred foals: 28 cases (1993–2007)

Reasons for performing study: Few studies have evaluated the athletic prognosis of foals affected by gastrocnemius disruption. Objective: To examine the diagnosis and management of gastrocnemius disruption in Thoroughbred (TB) foals, determine short‐term survival rate and assess future racing performance. The hypothesis was that Thoroughbred foals with gastrocnemius disruption are able to perform as racehorses comparably to their age matched maternal siblings. Methods: The medical records of foals diagnosed with gastrocnemius muscle disruption were reviewed. Information on training and racing was acquired from published works and race records. Paired t tests were utilised to compare performance variables of affected racehorses to their maternal siblings in starts, earnings and earnings/start for their 2‐ and 3‐year‐old racing seasons. Fisher's exact tests were employed to determine the association between sex, limb affected, age on admission, degree of caudal reciprocal apparatus dysfunction, concurrent disease, antibiotic therapy, complications, abscess formation and likelihood of entering training or starting a race. Results: Sample size was too small to detect significant differences in performance variables between affected horses and controls. Of 28 foals, 17 (61%) presented with concomitant illness; foals without concurrent disease were more likely to achieve race training or start a race (P = 0.04); 23 (82%) were short‐term survivors defined as survival to discharge. Of these 23 survivors, 7 were aged <2 years at the time of the study. Eighty‐one percent (13/16) of the survivors that were of racing age were in training or had started a race. Conclusions: In this population, 82% of TB foals affected with gastrocnemius disruption were able to achieve training or start a race. Foals presenting for gastrocnemius disruption have a high prevalence of concurrent disease processes. Potential relevance: The assessment of athletic prognosis and treatment complications provides useful information to clinicians treating gastrocnemius muscle disruption in foals and making recommendations to clientele.     

Racing performance following the laryngeal tie-forward procedure: a case-controlled study

REASONS FOR PERFORMING STUDY: The laryngeal tie-forward procedure (LTFP) is becoming widely used for correction of dorsal displacement of the soft palate (DDSP) despite the absence of an evidence-based assessment of its efficacy. HYPOTHESES: The LTFP returns racing performance to preoperative baseline levels and to that of matched controls; and post operative laryngohyoid position is associated with post operative performance. DESIGN AND POPULATION: Case-controlled study of racehorses undergoing a LTFP for dorsal displacement of the soft palate at Cornell University between October 2002 and June 2007. METHODS: The presence of at least one post operative start and race earnings ($) were used as outcome variables. Controls were matched by age, breed and sex from the third race prior to surgery. A novel radiographic reference system was used to determine laryngohyoid position pre- and post operatively. Data for definitively and presumptively diagnosed cases were analysed separately. RESULTS: During the study interval, 263 racehorses presented, of which 106 were included in the study; 36 had a definitive diagnosis of DDSP and 70 a presumptive diagnosis. Treated horses were equally likely to race post operatively as controls in the equivalent race. Treated horses had significantly lower earnings in the race before surgery than matched controls. The procedure moved the basihyoid bone dorsally and caudally and the larynx dorsally and rostrally. A more dorsal post operative basihyoid position and more dorsal and less rostral laryngeal position were associated with an increased probability of racing post operatively. CONCLUSIONS: Horses undergoing a LTFP are as likely to race post operatively as matched controls. The procedure restores race earnings to preoperative baseline levels and to those of matched controls. POTENTIAL RELEVANCE: This study provides strong evidence supporting the use of the LTFP in racehorses. Further work is needed to determine the relationship between laryngohyoid conformation and nasopharyngeal stability in horses.     

Characteristics of Thoroughbred and Quarter Horse racehorses that sustained a complete scapular fracture

Reasons for performing study: To determine if scapular fractures occur in racehorses with distinctive characteristics. Objectives: To test the hypothesis that Thoroughbred (TB) and Quarter Horse (QH) racehorses with a scapular fracture have similar characteristics that are different from those of their respective racetrack populations. Methods: Necropsy findings, case details, last race information and career earnings for TB and QH racehorses that had a scapular fracture in California between 1990 and 2008 were retrospectively compared between breeds. Horse signalment, career earnings, career starts and race characteristics were obtained for all California racehorses. Comparisons were made between affected horses, other racehorses that died, and all horses that raced, in California during the 19 year period. Results: Seventy‐three TB and 28 QH racehorses had a similar, complete comminuted scapular fracture with an articular component, and right forelimb predilection. The QHs had a higher incidence of scapular fracture incurred during racing than TBs (0.98 vs. 0.39/1000 starters). The TB and QH incident rates for musculoskeletal deaths incurred racing were 20.5 and 17.5/1000 starters, respectively; however, a greater proportion of TB musculoskeletal deaths occurred training (40% vs. 8%). Horses with a scapular fracture were more likely to be male and aged 2 or ≥5 years than the racetrack population. Most affected QHs (64%) were 2‐year‐olds; most TBs (74%) were aged ≥3 years. Scapular fractures occurred more commonly during racing in QHs (70%) than TBs (44%). Race‐related scapular fracture was more likely to occur in a Maiden race than in a non‐Maiden race. Horses with a scapular fracture had fewer career starts than the racetrack population. Conclusions and potential relevance: Despite breed differences for signalment and exercise distances, both breeds incur a complete scapular fracture that is more likely to occur in the right scapula of young and older, male racehorses, early in their race career or after few races. Quarter Horses sustain a catastrophic scapular fracture more frequently than TBs.     

Intralesional injection of platelet-rich plasma followed by controlled exercise for treatment of midbody suspensory ligament desmitis in Standardbred racehorses

OBJECTIVE: To determine outcome of Standardbred racehorses with moderate to severe midbody suspensory ligament desmitis (MSD) treated by means of ultrasound-guided intralesional injection of a single dose of platelet-rich plasma (PRP) followed by a program of gradually increased exercise. DESIGN: Nonrandomized clinical trial. ANIMALS: 9 Standardbred racehorses. PROCEDURES: Following injection of PRP, horses were allowed a controlled, gradual return to exercise. Race records for the year prior to injury and for 3 consecutive years after horses returned to racing were reviewed. For comparison purposes, race records of 9 Standardbred racehorses with no history of MSD racing at the same time were also reviewed. RESULTS: All 9 horses with MSD returned to racing after treatment; median time to return to racing was 32 weeks. All 9 horses raced at least once during the first and second years after returning to racing, but only 5 raced during the third year. When number of starts, total earnings, and earnings per start were compared between case and comparison horses, the only significant differences were number of starts during the third year after case horses returned to racing and earnings per start during the first year after case horses returned to racing, with values being significantly lower for case horses than for comparison horses. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that horses with moderate to severe MSD treated by means of intralesional injection of a single dose of PRP followed by a program of gradually increased exercise had an excellent prognosis for returning to racing.     

Surgical and nonsurgical management of sagittal slab fractures of the third carpal bone in racehorses: 32 cases (1991-2001)

OBJECTIVE: To compare results (ie, return to racing and earnings per race start) of surgical versus nonsurgical management of sagittal slab fractures of the third carpal bone in racehorses. DESIGN: Retrospective study. ANIMALS: 32 racehorses (19 Thoroughbreds, 11 Standardbreds, and 2 Arabians). PROCEDURE: Medical records and radiographs were reviewed to obtain information regarding signalment and treatment. Follow-up information was obtained from race records. Robust regression analysis was performed to evaluate earnings per start in horses that raced at least once before and after injury. RESULTS: 22 (69%) horses raced at least once after treatment of the fracture. All 7 horses treated by means of interfragmentary compression raced after treatment, and horses that underwent interfragmentary compression had significantly higher earnings per start after the injury than did horses treated without surgery. Eight of 9 horses treated by means of arthroscopic debridement of the damaged cartilage and bone raced after treatment, but only 7 of 16 horses treated without surgery (ie, stall rest) were able to return to racing after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that racehorses with sagittal slab fractures of the third carpal bone have a favorable prognosis for return to racing after treatment. Horses treated surgically were more likely to race after treatment than were horses treated without surgery.     

Sternothyroideus Tenectomy Combination Surgery: Treatment Outcome in 95 Thoroughbred Racehorses (1996–2006)

This retrospective case series reports on the clinical experiences of a group of Thoroughbred racehorses in training that were treated surgically for intermittent dorsal displacement of the soft palate (DDSP) using sternothyroideus tenectomy in combination with soft palate surgery. The 95 horses included in the study were Thoroughbred racehorses in training referred for surgical treatment of intermittent DDSP over a 10-year period. Return to racing was 94% (89/95). Total earnings increased for up to three starts before and after surgery in 65% of horses (62/95, P= .0006). Of the 58 horses that raced in three or more races before and after surgery, 71% (41/58) improved their total earnings. Mean days to first start were 106 days. Performance index improved in 64% of these horses (37/58). Sixty of the 95 horses (63%) raced in six or more races after surgery. Sternothyroideus tenectomy combination surgery had a good prognosis for improving earnings and performance index after surgery in this group of horses that were treated for a working diagnosis of intermittent DDSP.     

Sternothyroideus myotomy, staphylectomy, and oral caudal soft palate photothermoplasty for treatment of dorsal displacement of the soft palate in 102 thoroughbred racehorses

Objective— To compare racing performance before and after sternothyroideus myotomy, staphylectomy, and oral caudal soft palate photothermoplasty in Thoroughbred racehorses with intermittent dorsal displacement of the soft palate (DDSP).
Study Design— Retrospective study.
Animals— Thoroughbred racehorses (n=102) with DDSP.
Methods— Retrieved data included signalment, primary complaint, and upper respiratory tract endoscopic finding. Lifetime race records were compared for earnings per start before and after surgery, days to 1st start, and races won postoperatively.
Results— Comparing mean earnings per start for 3 races before ($2792) and after ($3806) surgery, racing performance improved significantly after surgery in 63% (46/73) of horses that competed in at least 1 race before and after surgery ( P =.02). Mean and median days to 1st start after surgery were 109 and 69 days, respectively. Of horses that raced postoperatively 65% (60/92) won at least 1 race, and 77% (71/92) raced in >5 races after surgery.
Conclusions— Sternothyroideus myotomy, staphylectomy, and oral caudal soft palate photothermoplasty significantly improved racing performance in experienced Thoroughbred racehorses with performance limiting DDSP, and overall had a similar outcome to other reported surgical techniques for treatment of DDSP.
Clinical Relevance— Sternothyroideus myotomy, staphylectomy, and oral caudal soft palate photothermoplasty should be considered as a surgical approach to correction of DDSP in Thoroughbred racehorses; however, it is possible that staphylectomy may not be necessary to achieve a desirable outcome.     

Arthroscopic removal of fractures of the lateral malleolus of the tibia in the tarsocrural joint: A retrospective study of 13 cases

There is limited information on the treatment of lateral malleolus (LM) fractures in the horse, with no previously published case series for the outcome following arthroscopic removal of such fractures. This report reviews and evaluates findings of a retrospective study of 13 horses admitted to a private equine referral hospital over a 10 year period (1999–2009) that underwent arthroscopic removal of fractures of the LM. Hospital records were reviewed and details including patient history, aetiology of the fracture and limb affected, results of all diagnostic tests and surgical reports were documented. Performance information concerning Thoroughbred horses that went onto race post operatively was collected using an online database. Owners and trainers were contacted regarding the return to performance for non‐Thoroughbred cases or those that did not go onto race post operatively. Of the 13 horses presented, 12 were Thoroughbreds, 9 of which were National Hunt racehorses and 3 were Flat racehorses. The other horse in the study was used for general purpose riding. All cases presented with an acute unilateral fracture. Eleven of the 13 had >6 months post operative follow‐up and all were nonlame. Of the 12 Thoroughbreds, 10 have raced again, a total of 104 times (median 5 times). The median time from surgery to return to racing was 241 days (180–366 days). It is concluded that horses with fractures of the LM have an excellent prognosis for return to full athletic performance following arthroscopic debridement; and that arthroscopic fragment removal is an appropriate treatment method for fractures of the LM.     

Association between exercise-induced pulmonary hemorrhage and performance in Thoroughbred racehorses

OBJECTIVE: To determine whether exercise-induced pulmonary hemorrhage (EIPH) was associated with racing performance inThoroughbred horses not medicated with furosemide and not using nasal dilator strips. DESIGN: Observational cross-sectional study. ANIMALS: 744 two- to 10-year-old Thoroughbred horses racing in Melbourne, Australia. PROCEDURE: Horses were enrolled prior to racing, and a tracheobronchoscopic examination was performed after 1 race. Examinations were recorded on videotape, and presence and severity (grade 0 to 4) of EIPH were subsequently determined by 3 observers blinded to the horses' identity. Race records were abstracted for each horse examined. RESULTS: Overall, 52.1% of horses eligible for participation in the study were examined, and horses that were examined did not differ from horses that were not examined in regard to age, sex distribution, or proportion of horses that won or finished in the first 3 positions. Horses with EIPH grades < 1 were 4.0 times as likely to win, 1.8 times as likely to finish in the first 3 positions, and 3.03 times as likely to be in the 90th percentile or higher for race earnings as were horses with grades > 2. Horses with EIPH grades > 1 finished significantly farther behind the winner than did horses without EIPH. However, odds that horses with grade 1 EIPH would win or finish in the first 3 positions were not significantly different from odds for horses without EIPH. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that EIPH is associated with impaired performance in Thoroughbred racehorses not medicated with furosemide and not using nasal dilator strips.     

Career racing performance in Thoroughbreds treated with prosthetic laryngoplasty for laryngeal neuropathy: 52 cases (1981-1989)

OBJECTIVE: To compare racing performance before and after prosthetic laryngoplasty for treatment of laryngeal neuropathy in inexperienced and experienced Thoroughbred racehorses. DESIGN: Retrospective study. ANIMALS: 52 Thoroughbred racehorses treated with prosthetic laryngoplasty for laryngeal neuropathy. PROCEDURE: Lifetime race records were analyzed by use of a verified regression model. Individual race records and hospital records were also reviewed. RESULTS: Experienced horses had a decline in performance, as measured by performance index, earnings percentage, and mean prediction error, during the 6-month period before prosthetic laryngoplasty. Performance improved after surgery, relative to performance in 1 to 4 races immediately before surgery, but did not attain previous baseline values for performance index and earnings percentage, although racing speed was restored to baseline values. Factors associated with failure to attain baseline levels of performance included other racing-related injuries and disorders, major complications of surgery, and age. Individually, however, many horses had long and successful careers after surgery. Performance of inexperienced horses after surgery was at least equal to that of experienced horses. CONCLUSIONS AND CLINICAL RELEVANCE: In addition to warning clients of the complications associated with prosthetic laryngoplasty, it may be prudent to provide a guarded prognosis for full restoration of racing performance in older horses, unless they are especially talented and are free of other racing-related problems.