Pantarsal arthrodesis in a pony using a locking compression plate

This report describes a case of pantarsal arthrodesis for the treatment of a comminuted fracture and luxation of the equine tarsus using a locking compression plate (LCP). A 20-year-old, 250-kg Welsh Pony cross presented with a severely comminuted fracture of the right tarsus. A dorsal approach to the tarsus was made and a 14-hole, 5.5-mm LCP was used to achieve arthrodesis. The pony was maintained in a full-limb cast for 30 days post-operatively. The incision healed by primary intention, and no surgical complications developed. The pony maintained excellent use of the limb and returned to pasture soundness.     

Comparison of limited-contact dynamic compression plate and locking compression plate constructs for proximal interphalangeal joint arthrodesis in the horse

This study compared in vitro monotonic and cyclic mechanical properties of equine proximal interphalangeal joint arthrodeses stabilized using an open or closed technique combined with axial 4.5 mm narrow limited-contact dynamic compression plate (LC-DCP) or 4.5 mm narrow locking compression plate (LCP). Ten forelimb pairs were randomly assigned to LCP or LC-DCP groups. One limb in each pair was assigned to either open or closed technique. Limbs were tested for cyclic fatigue at 20 000 cycles and then single-cycle to failure under 3-point dorsopalmar bending. There was no significant difference in stiffness of constructs during cyclic fatigue testing or on force or stiffness at failure in single cycle to failure testing between open and closed techniques or between plate types. Both implants, surgical technique, or combinations thereof are suitable for clinical use. More work is necessary to define the interaction between implant type and surgical technique.     

Clinical evaluation of a titanium, headless variable-pitched tapered cannulated compression screw for repair of frontal plane slab fractures of the third carpal bone in thoroughbred racehorses

OBJECTIVE: To report clinical evaluation of third carpal bone (C3) frontal plane slab fracture repair with the Acutrak screw system. STUDY DESIGN: Prospective case series. SAMPLE POPULATION: Racing Thoroughbreds (n=17) with frontal C3 slab fractures. METHODS: C3 slab fractures in Thoroughbred racehorses (1999-2004) were repaired by use of the Acutrak screw system. Data collected were (1) preoperative variables--gender, age at injury, limb involved, injury occurrence, fracture thickness, complexity, and displacement, race starts and earnings and (2) postoperative variables were: surgical complications, days to first start, race starts, and earnings. A Wilcoxon signed-rank test was used to compare pre- and postoperative starts and earnings; significance was set at P<.05. RESULTS: Seventeen Thoroughbred racehorses (12 females, 3 males, 2 geldings) were enrolled. Mean (+/-SD) age at injury was 3.3+/-1.0 years. Right carpi (10) were affected more than left (7). Ten injuries occurred during training, 7 during racing. Twelve of 15 horses that raced before injury returned to racing. Average days to first start was 349.3+/-153.9 days. Horses that returned to racing had more starts after repair (median, 6.5 versus 3.5; P=.04) and did not have decreased earnings per start (median, $2452 versus $3061; P=.30). CONCLUSION: The Acutrak screw system is a useful repair technique for frontal C3 slab fractures in Thoroughbred racehorses. CLINICAL RELEVANCE: Adequate reduction and stability of C3 slab fractures can be achieved with the Acutrak screw system, decreasing the likelihood of fragment splitting and screw head impingement on carpal soft tissues.     

A clinical evaluation of a headless, titanium, variable-pitched, tapered, compression screw for repair of nondisplaced lateral condylar fractures in thoroughbred racehorses

OBJECTIVE: To report clinical evaluation of headless compression screws for repair of metacarpal/metatarsal (MC/MT3) condylar fractures in horses. STUDY DESIGN: Retrospective case study. SAMPLE POPULATION: Racing Thoroughbreds (n=16) with nondisplaced lateral condylar fractures of MC/MT 3. METHODS: Medical records (1999-2004) of horses with nondisplaced longitudinal fractures of the lateral condyle of MC/MT3 were reviewed. Pre-operative variables retrieved were: patient age, gender, limb involvement, injury occurrence, fracture length, and width, evidence of palmar comminution and degenerative joint disease, number of pre-injury starts, and pre-injury earnings. Post-operative variables retrieved were: surgical complications, surgical time, number of race starts, and post-operative earnings. RESULTS: MC3 (n=11) and MT3 (5) nondisplaced longitudinal fractures of the lateral condyle were repaired with Acutrak Equine (AE) screws. Left front limb fractures were most common (8) followed by left hind (5) and right front (3). Nine fractures occurred during training and 7 during racing; 4 fractures had palmar comminution. No surgical complications occurred. Of 15 horses that returned to training, 11 (73%) raced 306+/-67 days after injury and had greater mean (+/-SD) post-injury earnings/start ($5290.00+/-$8124.00) than pre-injury ($4971.00+/-$2842.00). Screw removal was not required in any horse. CONCLUSION: The AE screw is a viable option for repair of nondisplaced lateral condylar MC/MT3 fractures in Thoroughbred racehorses. CLINICAL RELEVANCE: Adequate stability of nondisplaced lateral condylar fractures can be achieved with a headless tapered compression screw while avoiding impingement on the collateral ligaments and joint capsule of the fetlock joint.     

Minimally invasive proximal interphalangeal joint arthrodesis using a locking compression plate and tissue engineering in horses: A pilot study

This pilot study assessed the efficacy of 2 minimally invasive techniques for proximal interphalangeal (PIP) joint arthrodesis in horses. The PIP joints of both forelimbs (n = 6) were stabilized with locking compression plates (LCP) using a minimally invasive technique (LCP technique). Subsequently, for 1 randomly selected PIP joint of each horse, surgical drilling (SurD) was performed and tissue engineering (TE) was applied (LCP/SurD/TE technique). Minimally invasive PIP joint arthrodesis with LCP demonstrated low postoperative infection rates. Gross and histological evaluations revealed considerable destruction of the articular cartilage in the LCP/SurD/TE-treated joints. In contrast, almost no destruction of the cartilage was observed in the LCP-treated joints. Our results suggest that the LCP technique alone is not sufficient for PIP joint arthrodesis and that the LCP/SurD/TE technique may be useful for PIP joint arthrodesis in horses.     

Prevalence of carpal fractures in thoroughbred and standardbred racehorses

The prevalence of carpal fractures was determined for 211 thoroughbred and 75 standardbred racehorses. Statistically significant differences were found in the location of fractures between the 2 breeds. In the thoroughbred and standardbred groups, total fractures (460) were distributed nearly equally between the left (224) and right (236) carpi. The most common site of fracture in the thoroughbred group was the distal aspect of the radiocarpal bone (112), whereas the most common site of fracture in standardbred horses was the proximal surface of the third carpal bone (61). Slab fractures were more common in the right carpus of thoroughbred horses (29 right/11 left), but were distributed equally between the left (11) and right (11) carpi of the standardbred group. Fractures of the distal border of the radius and intermediate carpal bone were more common in the left carpi of the thoroughbred group and were relatively uncommon among standardbred horses. Fractures within the intercarpal joints (313) were more common than those within the radiocarpal joints (147) in thoroughbred and standardbred horses.     

Incidence and risk factors for exertional rhabdomyolysis in thoroughbred racehorses in the United Kingdom

Telephone surveys of 34 racing yards with 1276 horses in training were made to establish the overall incidence of exertional rhabdomyolysis in the previous year. A case-control study was used to investigate the risk factors for the syndrome in 12 yards selected on the basis of the routine confirmation of diagnoses by the evaluation of the serum activities of creatine kinase and aspartate aminotransferase. The overall incidence of the syndrome was 6.7 per cent and 80 per cent of the trainers had at least one affected horse. In 74 per cent of the affected horses it frequently recurred, with an average of six lost training days per episode. Risk factors identified for the syndrome included being female, having a nervous, excitable temperament, and being two years old.     

Conservative treatment for thoroughbred racehorses with intermittent dorsal displacement of the soft palate

Race records were obtained for 31 thoroughbred racehorses that were treated conservatively (rest, improvement of fitness and/or use of a tongue tie) for dorsal displacement of the soft palate, and for 62 matched control horses. Their racing performance, based on prize money won, was compared for three races run before and after the disorder was diagnosed. Nineteen (61 per cent) of the conservatively treated horses had higher earnings after conservative treatment than before treatment, compared with 27 (43.5 per cent) of the controls. There was a significant (P=0.049) increase in the earnings of the horses treated conservatively, but there was no significant difference in the earnings of the control group.     

Geometric symmetry of the solar surface of hooves of thoroughbred racehorses

OBJECTIVE: To define a 3-dimensional (3-D) coordinate system with clear definitions of origins and axes relative to hoof anatomic features and determine whether solar surfaces of Thoroughbred racehorse hooves have geometric asymmetry in the mediolateral and dorsopalmar directions. SAMPLE POPULATION: Left forelimb hooves from 20 Thoroughbred racehorse cadavers. PROCEDURE: A right-handed 3-D coordinate axes system centered on the collateral sulci was defined for the left front hoof. Orthogonal distances of anatomic features from the dorsopalmar axis and the plane coincident with the ground were measured and compared between medial and lateral sides and between dorsal and palmar regions of the hoof. RESULTS: The hoof was wider and had a greater radius laterally than medially. The most distal part of the lateral bar of the frog was further from the dorsopalmar axis than that of the medial bar. Overall, mediolateral asymmetries in depth were not observed. The sole at the perimeter was deeper medially in the dorsal part of the hoof and laterally in the palmar part, with depth overall being greater palmarly than dorsally. Most features had dorsopalmar asymmetry. CONCLUSIONS AND CLINICAL RELEVANCE: When the angle bisected by the collateral sulci is used to determine the dorsopalmar axis of the hoof, most central structures (bars and collateral sulci) have mediolateral symmetry. However, the hoof wall and sole have some mediolateral asymmetries and most structures have dorsopalmar asymmetry. These findings may assist the development of devices for attachment to hooves and studies of the interaction of hooves with bearing surfaces.     

Survey of arthroscopic surgery for carpal chip fractures in thoroughbred racehorses in Japan

Medical and racing records of 155 Thoroughbred racehorses that underwent arthroscopic surgery for carpal chip fractures were investigated. Articular damage for 98.4% of the fractures was classified as G1 or G2 using McIlwraith's criteria. The rate of return to racing after surgery was 82.6%. Evaluation of racing performance after surgery was attempted using a placing index (PI) based on race finish position. There was no significant difference in the PI distribution between horses that underwent surgery and other healthy horses.