Use of Electrocautery Probes in Arthroscopic Removal of Apical Sesamoid Fracture Fragments in 18 Standardbred Horses

OBJECTIVE: To develop a technique for arthroscopic excision of apical sesamoid fracture fragments using electrocautery probes. ANIMALS OR SAMPLE POPULATION: A total of 18 Standardbred horses. METHODS: Arthroscopic removal of apical sesamoid fracture fragments using both hook and loop electrocautery probes was performed on 18 Standardbred horses. The fracture fragments were approached using either an ipsilateral (3) or contralateral (15) arthroscopic triangulation technique. Distension of the metacarpo- (metatarso)-phalangeal joints was achieved using a 1.5% glycine solution. Under arthroscopic guidance, both the suspensory and intersesamoidean ligament attachments to the abaxial and the axial margins of the apical fragment were transected using a hook electrocautery probe. Subsequently, the palmar (plantar) soft tissue attachments to the apical fragment were transected with a loop electrocautery probe. Once freed of soft tissue attachments, the apical fragment was removed with Ferris-Smith intervertebral disc rongeur. The arthroscopic portals were closed in a routine manner. RESULTS: Horse ages ranged from 2 to 8 years (median, 2.5 years). Eighteen apical sesamoid fracture fragments were removed from the left (8) and right (8) hind limbs and the left (1) and right (1) forelimbs. Apical fragments occured in 15 lateral and 3 medial proximal sesamoid bones. No major complications occurred during or after surgery. The electrocautery probes permitted an easy and precise dissection of all soft tissue attachments to the apical sesamoid fracture fragments in all horses. Follow-up time was 7 to 44 months (median, 26 months); 10 of 14 horses returned to racing. Seven of nine horses that raced before surgery raced again and three of five that had not raced before surgery, raced afterwards. CONCLUSION: Arthroscopic excision of apical sesamoid fracture fragments can be accomplished arthroscopically using electrocautery probes. CLINICAL RELEVANCE: Arthroscopic electrosurgery is an efficient and safe alternative for intra-articular dissection in horses.     

Diagnosis and management of proximal sesamoid bone fractures in the horse

Fractures of the proximal sesamoid bones (PSBs) range in severity from simple to complex and comminuted and can be articular or nonarticular. The majority of PSB fractures are diagnosed in racehorses, but PSB fractures, especially simple ones, do occur in sport horses undertaking various disciplines. For simple apical, basilar and abaxial articular PSB fractures, surgical removal via arthroscopy carries the best prognosis for return to athletic performance. Removal of apical and abaxial PSB fractures generally result in a favourable prognosis for return to racing but are dependent on the amount of suspensory ligament injury. Removal of basilar PSB fracture fragments results in a less favourable or fair prognosis for return to racing. Mid‐body PSB fractures typically require (lag screw) surgical fixation preferably with arthroscopic guidance and carry a fair to guarded prognosis for return to racing.     

Arthroscopic surgery for osteochondral chip fragments and other lesions not requiring internal fixation in the carpal and fetlock joints of the equine athlete: What have we learned in 20 years?

Equine carpal and fetlock joints have been the most frequent sites for arthroscopic surgical procedures and were the initial locations where techniques were developed. The primary indication for surgical treatment of chip fragments in the equine athlete is normalization of the interior of the joint and prevention of osteoarthritis. Osteochondral chip fragments in the equine carpus are common in racehorses. The overall success rate with arthroscopic removal is 68.1% racing at a level equal to or better to preinjury in 88.6% starting at least one race. Depending on the degree of articular cartilage and bone damage, the prognosis for return to racing at a level equal to or better than preinjury ranges from 71% to 54%. Success rate with proximodorsal first phalanx chip fragments is 83.5% return to their previous use; 73.6% return to racing at the same level of performance. Other fracture fragments operated in the fetlock joint include, plantar or palmar first phalanx fragments, osteochondritis dissecans fragments from the sagittal ridge and distal dorsal metacarpus as well as apical, abaxial and basal sesamoid fragments. The success rates with these various arthroscopic surgeries are also presented.     

Size and geometry of apical sesamoid fracture fragments as a determinant of prognosis in Thoroughbred racehorses

Reason for performing study: Analysis was performed to examine a method for refining the preoperative prognosis for horses that had surgery to remove apical fractures of the proximal sesamoid bones (PSBs). Objectives: To determine if: 1) there was a difference in size or configuration of apical fractures between the different anatomical locations of the PSBs, which have been shown to affect the prognosis; and 2) the size or configuration could predict the prognosis for racehorses with these fractures. Methods: The study included 110 weanlings and yearlings and 56 training racehorses that underwent surgery to remove apical PSB fractures. Radiographs of the fractures were used for measurement of the abaxial and axial proportion and the abaxial to axial ratio, and race records were used to determine average earnings per start (AEPS) and total post operative starts. Analysis of variance and regression statistics were used to compare the fragment sizes between the specific PSBs on each of the limbs and compare size and configuration of the fractures to prognosis. Results: There was a significantly larger abaxial to axial ratio (more transverse fracture) for the forelimb medial sesamoids than for all other sesamoids in untrained racehorses (P = 0.03). There were no other significant differences in size. There was no relationship between fracture size or configuration and AEPS nor total post operative starts. Conclusions: Apical fractures in weanlings and yearlings tend to be more transverse in the forelimb medial PSBs than the other PSBs. Apical fracture size and geometry does not determine prognosis for apical sesamoid fractures. Potential relevance: Horses that undergo surgery to remove larger apical fractures of the PSBs do not have a worse outcome than those horses with smaller fractures.     

Management of proximal sesamoid bone fractures in the horse

The case records of 49 horses with proximal sesamoid bone fracture were studied. The population consisted of 20 Thoroughbreds, 20 Standardbreds, 5 Quarter Horses, 2 Arabians, and 2 grade horses. The fractured bones were classified into 5 categories: apical fractures, basilar fractures, abaxial fractures, middle one-third fractures, and bilateral comminuted-distracted fractures. Apical fractures occurred most frequently in the Standardbred, with the prevalence of medial fracture being equal to that of lateral fracture. Basilar fractures occurred predominantly in the Thoroughbred, with the highest prevalence in the lateral sesamoid bone of the right front fetlock. Bilateral comminuted-distracted fractures also occurred primarily in the right front fetlock. The prognosis following surgical removal of apical fractures appeared to be superior to that for stall rest alone. The prognosis for basilar fractures was poor.     

Abaxial tail attachment of bovine spermatozoa and its effect on fertility

The prevalence of abaxial sperm tails, accessory tails and double tails, was determined from semen evaluation records of 600 western Canadian range bulls and 449 bulls in Canadian artificial insemination centers. Spermatozoa with abaxial tails were produced by 10.5% of bulls, however, only 0.48% produced sperm with greater than 50% abaxial tails, and 0.86% of the 1049 bulls produced sperm with accessory and double tails. Three experiments were done to determine the importance of abaxial sperm tails to fertility. In experiments 1 and 2, frozen semen with 88%, 50% and 0% abaxial tails was used to inseminate synchronized heifers, which were allowed to develop pregnancy, and superovulated heifers, which were slaughtered prior to embryo recovery seven days after breeding. In experiment 3, a bull which produced 100% abaxial sperm was used in a competitive mating situation with three control bulls in a herd of 118 cows. The combined results of these experiments indicate that spermatozoa with abaxial tail attachment fertilize ova at a normal rate and are not associated with any increase in embryonic death.     

Effect of alkalinization on the local analgesic efficacy of ketamine in the abaxial sesamoid nerve block in horses

The objective of this study was to determine the effects of the alkalinization on the local analgesic efficacy of 1% ketamine in the abaxial sesamoid nerve block in horses. Thirty-six mature healthy horses were randomly assigned to four groups for the following treatments; an abaxial sesamoid block with 5 mL of saline solution (control saline); an abaxial sesamoid block with 5 mL of a solution containing 1% ketamine (KETs 1%); an abaxial sesamoid block with 5 mL of a solution containing saline solution and 0.5 mEq of sodium bicarbonate (control bicarbonate); and an abaxial sesamoid block with 5 mL of a solution containing 1% ketamine and 0.5 mEq of sodium bicarbonate (KETb 1%). All blocks were performed in one randomly selected front leg. To determine analgesia, hoof withdrawal from thermal stimulus from radiant heat lamp was assessed. Before each block, the hoof withdrawal reflex latency (HWRL) (time between lamp illumination and withdrawal of the hoof) was determined; after the block, local analgesic effects were determined using the heat lamp at 2 and 5 min after the injection and then every 5 min for 1 h. In KETs 1% group, there were significant increases in HWRL between basal values and values from 2 to 10 min after an abaxial sesamoid block. In KETb 1% group, significant increases in HWRL was collected between the basal value and values from 2 to 25 min following an abaxial sesamoid block. In KETs 1% group, of the nine horses, four had an abaxial sesamoid block that was unsuccessful. However, in KETb 1% group, only one of the nine horses had an abaxial sesamoid nerve block that was unsuccessful. The alkalinization of a 1% ketamine solution produced a more consistent and persistent local analgesia in horses when compared with 1% ketamine solution alone.     

Racing performance after arthroscopic removal of apical sesamoid fracture fragments in Thoroughbred horses age < 2 years: 151 cases (1989--2002)

REASONS FOR PERFORMING STUDY: Studies on arthroscopic removal of apical proximal sesamoid fracture fragments in Thoroughbred (TB) horses age > or = 2 years have reported a high success rate. However, there are no reports documenting the racing prognosis of TB horses that undergo such surgery as weanlings or yearlings. OBJECTIVES: To describe the incidence of apical proximal sesamoid fractures in immature TB horses, age < 2 years and determine probability and quality of racing performance after arthroscopic removal of such fractures in 151 TB weanlings and yearlings. METHODS: The medical records of TB horses age < 2 years that underwent arthroscopic surgery for removal of apical proximal sesamoid fracture fragments were reviewed. Follow-up information was obtained from race records. Student's t tests were used to compare performance variables of operated racehorses to that of their maternal siblings. RESULTS: Ninety-two percent (139/151) of fractures occurred in the hindlimbs and 8% (11/151) in the forelimbs (fracture of both fore- and hindlimb, n = 1). Horses with forelimb fractures had a greatly reduced probability of racing (55%) compared to those with hindlimb fractures (86%). Overall, 84% of the horses raced post operatively and had performance records similar to that of their maternal siblings, 78% (787/1006) of which raced. CONCLUSIONS: Arthroscopic removal of apical proximal sesamoid fracture fragments in TB weanlings and yearlings carries an excellent prognosis for racing in horses with hindlimb fractures and a reduced prognosis in those with forelimb fractures. Medial fractures of the forelimb carry the worst prognosis. POTENTIAL RELEVANCE: The determination of prognosis increases knowledge on apical sesamoid bone fractures and potential for arthroscopic restoration of the ability to race; and enables the value of yearlings for subsequent sale to be established.     

Zusammenhang zwischen Fertilität und Kopfschwanzkoppelung bei Eberspermien

Abstract: Relationship between the implantation of the tails and the fertility in boars In this study ejaculates of 47 different breed and age boars were examined. The aim of this study was to determine the relationship between the implantation of the tails and the fertility in boars. From the evaluation of 115 ejaculates it was observed that the rate of abaxial implantation of the tails in ejaculates of boars was very fluctuating. The rate of axial and abaxial implantation of the tails was stable in the ejaculates of the same boars. Although some studies indicate that abaxial implantation can be the reason for infertility the present authors observed better fertilisation results with ejaculates having higher percentages of abaxial spermatozoa.     

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.     

External Skeletal Fixation of Comminuted Maxillary Fractures in Dogs

An external skeletal fixation technique that was effectively applied on comminuted maxillary fractures is described. With this method, pairs of Kirschner wires and/or Steinman pins were seated into the fracture fragments and the exposed cut ends of the pins were embedded into an acrylic bridge. Excellent stabilization of the fractures was effected and normal oral alimentation was resumed immediately. Healing of the fractures usually occurred within two or three months and the pins were then removed. Three representative cases are presented.     

The bovine digital cushion--a descriptive anatomical study

The properties of the suspensory and supporting structures of the bovine claw are of particular importance in the pathogenesis of claw lesions since both must function optimally to prevent soft tissue compression and trauma. An essential component is the shock-absorbing digital cushion situated under the distal phalanx. The sound claws of 54 slaughtered cows were dissected. The digital cushion consisted of three parallel pads--axial, middle and abaxial--that ran longitudinally from the heel and underneath the distal phalanx with numerous transverse finger-shaped branches that connected the axial and abaxial pads cranial to the flexor process of the distal phalanx. The middle fat pad frequently ended just at the apical end of the flexor process of the distal phalanx, which may result in an inferior cushioning effect under the distal phalanx and increase the likelihood of ulcers. There were differences in the structure of the digital cushion with age and loose connective tissue in heifers' pads was first replaced by fat which, after the third lactation, was gradually supplanted by collagenous connective tissue.     

Arthroscopic removal of axial osteochondral fragments of the proximoplantar aspect of the proximal phalanx using electrocautery probes in 23 standardbred racehorses

OBJECTIVES: To describe the outcome after arthroscopic electrosurgical excision of axial osteochondral (OC) fragments of the proximal plantar aspect of the 1st phalanx (P1) in horses. STUDY DESIGN: Retrospective study. POPULATION: Twenty-three Standardbred racehorses. METHODS: Medical records of Standardbred racehorses that had arthroscopic dissection of axial OC fragments of the proximal plantar aspect of P1 with electrocautery probes were reviewed. Horses were positioned in dorsal recumbency; a 1.5% glycine solution was used to maintain joint distension. The arthroscope portal was in the proximal plantar joint pouch and OC fragments were approached using either an ipsilateral or a contralateral triangulation technique. Dissection of the fibrous attachments was performed using loop and hook electrocautery probes. Follow-up was obtained by telephone questionnaire of owners or trainers and examination of race summary records. RESULTS: Thirty-three axial OC fragments were removed from 28 metatarsophalangeal joints (left, 14; right, 14). No major operative or postoperative complications occurred. Seven of 8 (79%) of horses that raced before surgery raced after surgery. Thirty-six percent (n=4) of horses that had not raced before surgery raced after surgery. CONCLUSION: Intra-articular electrosurgery is a safe, easy alternative to conventional excision of axial OC fragments of the proximal plantar aspect of P1. CLINICAL RELEVANCE: Arthroscopic excision using electrocautery probes is a valid alternate method for removal of axial OC fragments of the proximal plantar aspect of P1. In addition, the dorsal recumbency position facilitates removal of several fragments and multiple joint surgery.     

Identification of grazed grasses using epidermal characters

The use of anatomical features of the abaxial epidermis of grasses is discussed for the identification of fragments of epidermis present in samples of rumen. The reliability of this technique, and the variation of the epidermal characters in two widely distributed species of grass, is given. A “Key” to identity certain genera of grasses occurring in Southern Africa, based on epidermal characters, is presented. The application of the technique to analyse rumen contents of .springbok and Merino sheep is shown.     

Modulus of elasticity and dry-matter content of bovine claw horn affected by the changes of chronic laminitis

The mechanical properties of horn samples from 22 hind claws with chronic laminitis were determined in adult Austrian Fleckvieh cows. The resistance to deformation was quantified as the modulus of elasticity (E). Tension tests revealed mean E values of 520MPa for the dorsal wall, 243MPa for the abaxial wall, 339MPa for the axial wall and 97MPa for the sole. E tended to be lower in laminitic horn than in sound horn in all segments tested, with the difference being largest in the abaxial wall. The mean dry-matter content (DMC) of the laminitic claws was 75.8% in the dorsal wall, 75.86% in the abaxial wall, 71.15% in the axial wall and 69.28% in the sole. These values are generally comparable to those for sound claws except in the axial wall. Further, E and DMC were only correlated in the axial wall. Chronic laminitis leads to a low resistance of claw horn to mechanical insults in the dorsal wall, abaxial wall and sole, and to the loss of a correlation between the E and DMC in these segments. The reason for these alterations is therefore not increased ingress of moisture, but must be due to changes in the microstructure, biochemical components and/or horn formation by the diseased dermis.     

Microstructure and Hardness of Buffalo's Hoofs

The aim of this study was to describe the microstructure of hoof capsules of the buffalo. In addition, the study emphasized the morphometric aspects of the horn tubules, the Vickers nanohardness of the dorsal and abaxial walls and sole of the digits of the thoracic and pelvic limbs of the buffalo. The abaxial wall in the thoracic and pelvic digits showed larger diameter of the horn tubules when compared to all dorsal wall and sole. In addition, the abaxial wall of the thoracic digits showed larger diameter of the horn tubules when compared with the pelvic digits. According to the three‐dimensional microtomography, the dorsal wall was higher in density compared with the abaxial wall. The latter exhibited an intermediate density, while the sole showed the lowest density. The Vickers nanohardness test showed that there was no difference in hardness and resistance between the experienced regions. However, the elastic modulus was greater on the transversal section of the hoof capsule. In conclusion, the results of the current study show that modern technologies such as microtomography and subsequent imaging can be used to investigate details of the basic morphology in different regions of the buffalo's hoof.     

Fenestration of the abaxial hoof wall and implantation of gentamicin-impregnated collagen sponges for the treatment of septic arthritis of the distal interphalangeal joint in cattle.

A novel surgical approach to the distal interphalangeal joint of cattle, through the abaxial hoof wall, for the treatment of septic arthritis is described. In seven cattle a rectangular piece of horn (15 x 40 mm) was excised from the abaxial hoof wall and the joint was lavaged with Ringer's solution. Infected and/or necrotic tissue was removed from the joint and gentamicin-impregnated collagen sponges were introduced. The piece of horn was reattached, a rubber block was glued to the contralateral claw, and a bandage applied. Aftercare consisted of changes of bandage, systemic administration of antimicrobial drugs and box rest. At follow-up, six of the cattle were sound but one cow which had been slaughtered five months after surgery had remained slightly lame.     

不同光质对黄秋葵幼苗生长、光合色素和气孔特征的影响

以黄秋葵品种‘五福’为试材,采用单因素随机区组设计,探讨不同光质对黄秋葵幼苗生长、光合色素和气孔特征的影响。试验结果表明:与荧光灯(CK)处理相比,蓝光(B)、紫光(P)、红光(R)和蓝红复合光(BR)处理下的黄秋葵幼苗的鲜质量、干质量及其叶片的光合色素含量等指标均有不同程度的增加,且以BR处理为最高;在黄秋葵幼苗叶片气孔特征方面,其上表皮的气孔密度以BR和R处理下最大,而下表皮的气孔密度仅BR处理下最大;上、下表皮的气孔长轴长度,以BR处理下最大,B处理次之;上表皮的气孔短轴长度及气孔弧长均在BR处理下最大,而下表皮的气孔短轴长度、气孔弧长以B处理下最大,BR处理次之。可见,BR处理能显著促进黄秋葵幼苗的生长,幼苗生长快速健壮,并提高了叶片光合色素的含量,气孔发育相对较好,因此可采用BR作为黄秋葵育苗的人工光源。     

Mineral composition and microstructure of the abaxial hoof wall in dairy heifers after biotin supplementation

The aim of this study was to evaluate the effect of daily biotin supplementation on the mineral composition and microstructure of the abaxial hoof wall in dairy heifers. The heifers were housed on a concrete floor and fed for weight gain more than 800 g per day, which is a challenging environment for the hoof. Twelve crossbred dairy heifers (Jersey × Holstein) were divided into two treatment groups. Animals in the control group (n = 6) received a diet without supplemental biotin, while the heifers in the biotin-supplemented feed group (n = 6) each received 20 mg of biotin daily for 120 days. Samples of the abaxial hoof wall were collected from the outer claw of the fore and hind limb, before and after supplementation. The samples were evaluated by X-ray fluorescence spectrometry, computed microtomography, atomic force microscopy and confocal laser scanning microscopy. Biotin supplementation increased the sulphur content and decreased the calcium and potassium content in the abaxial hoof wall. Biotin treatment also increased the percentage of horn tubules with smaller diameter marrow (17–51 µm). However, biotin did not influence the surface relief of the hoof wall, suggesting that its action is limited to the inner layers of the stratum corneum. Daily supplementation with 20 mg of biotin promoted changes in the mineral composition and microstructure of abaxial hoof wall of crossbred dairy heifers. These findings suggest biotin supplementation improves hoof quality and may help to understand the function of biotin in the stratum corneum.     

Biomechanical investigation of the association between suspensory ligament injury and lateral condylar fracture in thoroughbred racehorses

Objective-To determine whether partial transection of the medial branch of the suspensory ligament (MBSL) alters equine third metacarpal bone (MC3) condylar surface strains and forelimb, distal joint angles in a manner consistent with promotion of lateral condylar fracture. Study Design-In vitro biomechanical experiment. Sample Population-Right forelimbs from 7 Thoroughbred horse cadavers. Methods-Lateral and medial MC3 condylar, dorsal and abaxial, bone surface strains and distal joint angles were measured both before and after partial transection of the MBSL during in vitro axial limb compression. Dorsal, principal bone strains and abaxial, uniaxial, and proximodistal strains were compared before and after MBSL partial transection at 1,400-, 3,000-, and 5,600-N loads. Results-Bone strains increased in all locations with increasing axial load. All lateral condylar bone strains were significantly higher, and abaxial surface medial condylar bone strain was significantly lower, after partial transection of the MBSL. Respective distal joints became more flexed or extended as axial load increased but were not significantly different after partial transection of the MBSL. Conclusions-Partial transection of the MBSL increases in vitro MC3 lateral condylar bone surface strains. Clinical Relevance-Loss of integrity of the medial branch of the suspensory ligament could increase the risk for lateral condylar fracture in Thoroughbred horses by amplifying bone strain in the lateral condyle.