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Biomedical subjects

S J Dyson

Publications and source records attributed to S J Dyson.

At least 19 recordsLinked to original sources
PubMed2006

Risk factors for colic in horses after general anaesthesia for MRI or nonabdominal surgery: absence of evidence of effect from perianaesthetic morphine.

REASON FOR PERFORMING STUDY: Post anaesthetic colic is a recognised risk of general anaesthesia (GA), but causes are poorly understood. OBJECTIVES: To identify risk factors for development of colic following GA for magnetic resonance imaging (MRI) or nonabdominal surgery and to test whether the use of perianaesthetic morphine was associated with an increased risk of post anaesthetic colic. METHODS: A total of 553 anaesthetic and clinical records of 500 horses anaesthetised at the Animal Health Trust were analysed, 342 (62%) involved MRI and 211 (38%) nonabdominal, predominantly orthopaedic surgery. Multivariable logistic regression analysis was used to examine the association between post anaesthetic colic and explanatory variables, including use of perianaesthetic morphine. RESULTS: Twenty horses (3.6%) developed colic within 7 days of GA. A significantly larger (P = 0.001) proportion of the surgical cases developed post anaesthetic colic (7.1%) compared with MRI cases (1.5%). Having controlled for the effect of MRI/surgeon, there was evidence for a significantly increased risk of colic associated with maintenance of anaesthesia with isoflurane and administration of benzyl penicillin and/or ceftiofur. A reduction in risk of colic was associated with premedication with romifidine, longer duration of anaesthesia and sedation within 2 days of GA. Perianaesthetic morphine administration was not associated with increased risk. CONCLUSIONS: This study identified apparently novel risk factors for colic in horses following GA. Use of morphine was not found, after controlling for other MRI and surgery related risk factors, to be associated with an increased risk. The low prevalence of colic after GA and resulting low study power mean that further larger, multicentre collaborative studies are warranted to corroborate findings in this study. POTENTIAL RELEVANCE: Better knowledge of risk factors should lead to achievable measures to reduce frequency of occurrence.

Anesthesia, General↗
PubMed2005

Lameness associated with foot pain: results of magnetic resonance imaging in 199 horses (January 2001--December 2003) and response to treatment.

REASONS FOR PERFORMING STUDY: The diagnosis of foot-related lameness often remains elusive and it can be difficult to offer rational treatment, or to predict outcome. OBJECTIVES: To describe the spectrum of injuries of the foot identified using magnetic resonance imaging (MRI), to determine their relative prevalence among MRI diagnoses and to establish the long-term results of treatment. METHODS: The MR images of horses examined from January 2001--December 2003 were reviewed. Horses were selected for MRI if the pain causing lameness was localised to the foot using perineural analgesia but any clinical, radiological or ultrasonographic abnormalities were insufficient to explain the degree of lameness. The clinical significance of lesions identified using MRI was determined with reference to the results of local analgesia, radiography, ultrasonography and nuclear scintigraphy. Follow-up information was obtained in January 2004 for horses which had been examined 6-36 months previously and the outcome classified as excellent (horse returned to full athletic function without recurrent lameness), moderate (sound, but only in light work), or poor (persistent or recurrent lameness). RESULTS: One hundred and ninety-nine horses underwent MRI examinations. Deep digital flexor (DDF) tendonitis was the most common injury (59%) with primary injury in 65 horses (33%) and a further 27 horses (14%) having lesions of the DDF tendon and navicular bone. Seventeen percent of horses had injuries to multiple structures, including 24 with DDF tendonitis. Desmitis of a collateral ligament (CL) of the distal interphalangeal (DIP) joint was the second most common injury (62 horses, 31%), with primary injuries in 30 horses (15%) and a further 32 horses (16%) that had CL desmitis in conjunction with other injuries. Prognosis was best for horses with traumatic injuries of the middle or distal phalanges, with 5 of 7 horses (71%) having an excellent outcome. Horses with primary lesions of the DDF tendon or CL of the DIP joint had excellent results in only 13 of 47 (28%) and 5 of 17 horses (29%), respectively. Horses with combined injuries of the DDF tendon and navicular bone, or primary navicular bone abnormalities, had a poor outcome, with the majority of horses suffering persistent lameness. CONCLUSIONS: A wide variety of lesions associated with foot pain were identified using MRI, a high proportion of which were primary soft tissue injuries with a guarded prognosis for return to full athletic function. POTENTIAL RELEVANCE: It is now possible to propose more rational treatment strategies for the variety of foot injuries identified using MRI than had previously been possible; however, further information concerning aetiopathogenesis of these injuries is needed to improve their management.

Animals↗
PubMed2005

Osteoarthritis of the talocalcaneal joint in 18 horses.

REASONS FOR PERFORMING STUDY: Talocalcaneal osteoarthritis (TO) is an uncommon cause of moderate to severe hindlimb lameness, on which only isolated case reports have been published to date. OBJECTIVES: To review the clinical features of TO and determine optimal methods for diagnosis, management and prognosis. METHODS: The case records from 4 referral centres of 18 horses showing hindlimb lameness considered, as a result of clinical investigation, to be caused by TO, were reviewed. RESULTS: TO affected mature sports and pleasure horses (age 7-16 years) and caused moderate to severe lameness, usually of sudden onset with no obvious inciting cause. There were few localising signs, other than worsening of lameness by hock flexion. Tarsocrural joint analgesia produced improvement in lameness in 6/11 horses (55%) and perineural analgesia of the tibial and fibular nerves complete soundness in 6/14 horses (43%) in which it was performed; 7/14 horses (50%) showed a further substantial improvement. Radiological findings included subchondral bone lysis and sclerosis and irregular joint space width, seen most obviously in a lateromedial view. Nuclear scintigraphy revealed marked uptake of radiopharmaceutical predominantly plantaromedially in the region of the talus in the 7 horses in which it was performed. Fourteen horses were treated conservatively with box- or pasture-rest, with or without intra-articular corticosteroids, hyaluronic acid or polysulphated glycosaminoglycan, and all remained lame. Intra-articular corticosteroids appeared to have no effect in any horse. Of 10 horses receiving conservative management only, 6 were subjected to euthanasia, 3 were retired and 1 remained in light work, but was still lame. Two horses treated by either partial tibial and fibular neurectomy or subchondral forage failed to regain soundness and were retired. Six horses were treated by surgical arthrodesis of the talocalcaneal joint with 2 or three 5.5 mm AO screws introduced obliquely across the joint from the plantarolateral aspect of the calcaneus, which resulted in improvement in lameness in all cases. CONCLUSIONS: Osteoarthritis of the talocalcaneal joint causes acute onset severe lameness, but clinical findings and diagnostic analgesia often fail to identify precisely the site of pain. Consistent radiographic changes suggested TO was contributing to the lameness and this diagnosis was supported by nuclear scintigraphy. The poor success of conservative treatment (including intra-articular medication) suggests that surgical arthrodesis is the treatment of choice, although the prognosis is still poor for a return to full soundness. POTENTIAL RELEVANCE: The clinical features described should facilitate more accurate diagnosis and prognosis. A novel surgical treatment is described which appears to offer significant improvement in the lameness. Further work is necessary to determine the causes of this condition and more effective management.

Animals↗
PubMed2005

Is there a characteristic distal tarsal subchondral bone plate thickness pattern in horses with no history of hindlimb lameness?

REASONS FOR PERFORMING STUDY: Osteoarthritis (OA) is a common cause of distal tarsal pain, but disease development is poorly understood. Awareness of normal tarsal structure and function is important in order to understand the pathogenesis of OA. Thickening of the subchondral bone (SCB) plate has been related to the development of OA, but SCB plate patterns in the equine tarsus have not been documented. HYPOTHESES: There is a repeatable pattern of SCB thickness across the distal tarsal joints, and specifically that thickness would be greatest dorsally and laterally. METHODS: Twenty cadaver tarsi were collected from mature horses that had undertaken low-level exercise only with no history of hindlimb lameness. Magnetic resonance images were acquired using a high-resolution sagittal 3-dimensional T1-weighted spoiled gradient echo sequence. Subchondral bone thickness was measured on sagittal images at dorsal and plantar locations on the proximal and distal aspects of the central (CT) and third (T3) tarsal bones and proximal aspect of the third metatarsal bone (Mt3). RESULTS: On the proximal aspect of CT, medial and lateral SCB thickness were significantly greater than midline. On the distal aspect of CT and T3 and proximal Mt3, lateral SCB thickness was significantly greater than medial and midline sites. Dorsal SCB thickness was greatest on the proximal and distal aspects of CT and proximal Mt3. Subchondral bone accounted for a greater proportion of CT and T3 on the dorsal aspect than the plantar. CONCLUSIONS: There is a repeatable pattern of SCB thickness in the distal tarsal bones of horses with no history of hindlimb lameness. This reflects the pattern of loading across the joints. POTENTIAL RELEVANCE: This study provides evidence of a consistent osteochondral pattern in the equine tarsus for reference in identification of osteoarticular pathologies.

Animals↗
PubMed2004

Medical management of superficial digital flexor tendonitis: a comparative study in 219 horses (1992-2000).

REASONS FOR PERFORMING STUDY: There is a lack of long-term follow-up data for outcome of medical treatment of superficial digital flexor (SDF) tendonitis. OBJECTIVES: To determine whether intralesional injection of hyaluronan, beta aminoproprionitrile fumarate (BAPN) or polysulphated glycosaminoglycans (PSGAG) or systemic administration of PSGAG yielded better results than a controlled exercise programme alone in the management of SDF tendonitis, with a minimum follow-up period of 2 years after resumption of full work; and to determine whether reinjury rate was related to sports discipline and whether fibre alignment score (FAS) at 4 months could predict outcome. METHODS: In Study 1, 50 horses were managed by controlled exercise alone (Group A), 50 were treated with intralesional injection of hyaluronan (Group B), 20 received intralesional and systemic treatment with PSGAG (Group Ci) and 30 received systemic treatment with PSGAG (Group Cii). Horses in Groups B, Ci and Cii followed the same controlled exercise programme as Group A. In Study 2, 69 horses (Group D) were treated by intralesional injection of BAPN and followed a modified controlled exercise programme. Horses were re-examined clinically and ultrasonographically at intervals. Follow-up data were obtained for horses 2 years after resuming full work and for up to 6 years. RESULTS: There was no significant difference in reinjury rate of the treated limb(s) between Groups A, B, Ci and Cii (42.5-44.4%) (P>0.9). The reinjury rate (16%) in the treated limb(s) in Group D was significantly lower than in the other groups (P<0.001). However, when injury rate of the uninjured limb was considered, the results were similar to Study 1. In Study 2, the FAS at 4 months after treatment was a good predictor of outcome (P<0.001). Reinjury rates for different disciplines were similar in the 2 studies, with the risk of reinjury ascending from showjumpers to event horses to National Hunt and flat racehorses. CONCLUSIONS: Treatment with BAPN reduced the risk of reinjury in the treated limb, although the overall rate of subsequent injury was not affected. FAS at 4 months after treatment is a good predictor of outcome in the treated limb(s). POTENTIAL RELEVANCE: This study provides long-term follow-up data in horses from a variety of sports disciplines that can be used to provide prognostic information.

Adjuvants, Immunologic↗
PubMed2004

Collateral desmitis of the distal interphalangeal joint in 18 horses (2001-2002).

REASONS FOR PERFORMING STUDY: There have been no previously published case series of horses examined using either scintigraphy or MRI to diagnose collateral ligament injuries not detectable using ultrasonography or radiography, nor have other concurrent soft tissue lesions been described. OBJECTIVES: To describe the clinical features of horses with desmitis of the collateral ligaments of the distal interphalangeal (DIP) joint and to evaluate the results of radiographic, ultrasonographic, scintigraphic and magnetic resonance imaging (MRI) examinations. METHODS: Horses were examined between January 2001 and January 2003 and were selected for inclusion in the study if there was unequivocal evidence of collateral desmitis of the DIP joint based on ultrasonography or MRI. Subject details, case history, results of clinical examination and responses to local analgesic techniques were reviewed. The results of radiographic, ultrasonographic, scintigraphic and MRI examinations were assessed. RESULTS: Eighteen horses were identified with desmitis of a collateral ligament of the DIP joint, 3 horses (Group 1) based on ultrasonography alone, 7 (Group II) with positive ultrasonographic and magnetic resonance images and 8 (Group III) with no lesion detectable using ultrasonography, but lesions identified using MRI. Seventeen horses had forelimb injuries and one a hindlimb injury. The medial collateral ligament was injured most frequently (13 horses). In the majority of horses, no localising clinical signs were seen. Lameness was invariably worse in circles compared with straight lines. Lameness was improved by palmar digital analgesia in 16 horses (87%), but only 6 were nonlame. Intra-articular analgesia of the DIP joint produced improvement in lameness in 6/15 horses (40%). In 16 horses, no radiographic abnormality related to the DIP joint or collateral ligament attachments was identified. Eight of 14 horses (57%) had focal, moderately or intensely increased radiopharmaceutical uptake (IRU) at the site of insertion of the injured collateral ligament on the distal phalanx. Alteration in size and signal in the injured collateral ligament was identified using MRI. In addition, 5 horses had abnormal mineralisation and fluid in the distal phalanx at the insertion of the ligament. Eleven horses had concurrent soft tissue injuries involving the deep digital flexor tendon, distal sesamoidean impar ligament, navicular bursa or collateral ligament of the navicular bone. CONCLUSIONS AND POTENTIAL RELEVANCE: Collateral desmitis of the DIP joint should be considered as a cause of foot lameness. Although some injuries are detectable ultrasonographically, false negative results occur. Focal IRU at the ligament insertion on the distal phalanx may be indicative of injury in some horses. MRI is useful for both characterisation of the injury and identification of any concurrent injuries. Further follow-up information is required to determine factors influencing prognosis.

Animals↗
PubMed2004

Treatment of chronic or recurrent proximal suspensory desmitis using radial pressure wave therapy in the horse.

REASONS FOR PERFORMING STUDY: Proximal suspensory desmitis (PSD) is diagnosed with increasing frequency in horses and radial pressure wave therapy (RPWT) is a widely used therapy for painful orthopaedic conditions in man and dogs. There are, however, few published data as to the outcome of its use in PSD. OBJECTIVE: To evaluate the use of RPWT in the treatment of chronic or recurrent PSD in the horse, an injury which carries a poor prognosis for return to athletic function with conservative management alone. HYPOTHESIS: RPWT and controlled exercise improves the prognosis of chronic or recurrent PSD in the horse when compared to previously published results of controlled exercise alone. METHODS: The use of RPWT in the management of chronic or recurrent proximal suspensory desmitis (PSD) was evaluated in 65 horses. Diagnosis was based on response to local analgesia, ultrasonography and radiography. Horses were classified according to severity of ultrasonographic lesions, whether fore- or hindlimbs were affected, and duration of lameness prior to diagnosis. Horses were treated 3 times at 2-week intervals and followed a controlled exercise programme; they were reassessed clinically and ultrasonographically 10-12 weeks after diagnosis, when further exercise recommendations were made dependent upon the animal's progress. RESULTS: Forty-one percent of horses with hindlimb lameness and 53% with forelimb lameness were nonlame and returned to full work 6 months after diagnosis. The prognosis was significantly affected by the ultrasonographic grade at the time of diagnosis and by ultrasonographic evidence of resolution of the lesion in hindlimb cases. CONCLUSIONS: These findings, when compared to previously published results of treatment using controlled exercise alone, suggest that RPWT improves the prognosis for PSD in the hindlimb. POTENTIAL RELEVANCE: RPWT is a useful treatment modality for chronic or recurrent PSD when combined with controlled exercise. Further studies are required on the effect of RPWT employing histology and biomechanics in order to fully evaluate its use on equine tissues.

Age Distribution↗
PubMed2002

Normal ultrasonographic anatomy and injury of the patellar ligaments in the horse.

The purposes of this study were to investigate the ultrasonographic appearance of the patellar ligaments in clinically normal horses and to describe the clincical features, diagnosis and outcome of patellar ligament injury. The medial, middle and lateral patellar ligaments of 5 Thoroughbred and 5 Warmblood horses, free from lameness and in full work, were examined ultrasonographically. The ligaments were all of uniform echogenicity and each ligament was fairly consistent in its shape. The size of the ligaments of the Warmblood horses tended to be bigger than the lighter bodyweight Thoroughbred horses. The bone surfaces were smooth at the ligament insertions on the patella and tibia. Nine horses, including 7 showjumpers, were identified with a unilateral hindlimb lameness associated with ultrasonographic evidence of damage to one or more patellar ligaments. Four horses had primary desmitis of the middle patellar ligament, one of which had concurrent intermittent upward fixation of the patella and a second had abnormal movement of the patella. Two additional horses had desmitis of the middle patellar ligament associated with previous medial patellar desmotomy. Two horses had desmitis of both the middle and lateral patellar ligaments, and one horse had desmitis of the lateral patellar ligament alone. None of the 9 horses were able to return consistently to their former level of competition. Careful clinical evaluation and ultrasonographic examination of the patellar ligaments should be considered in horses with hindlimb lameness of otherwise undetermined cause.

Animals↗
PubMed2002

Subjective and quantitative scintigraphic assessment of the equine foot and its relationship with foot pain.

It was hypothesised that in solar bone images of the front feet of clinically normal horses, or horses with lameness unrelated to the front feet, there would be less than a 10% difference in the ratio of uptake of radiopharmaceutical in either the region of the navicular bone, or the region of insertion of the deep digital flexor tendon (DDFT), compared to the peripheral regions of the distal phalanx. Nuclear scintigraphic examination of the front feet of 15 Grand Prix show jumping horses, all of which were free from detectable lameness, was performed using dorsal, lateral and solar images. The results were compared with the examinations of 53 horses with primary foot pain, 21 with foot pain accompanying another more severe cause of lameness and 49 with lameness or poor performance unrelated to foot pain. None of the horses with foot pain had radiological changes compatible with navicular disease. All the images were evaluated subjectively. The solar views were assessed quantitatively using regions of interest around the navicular bone, the region of insertion of the deep digital flexor tendon and the toe, medial and lateral aspects of the distal phalanx. In 97% of the feet of normal showjumpers, there was <10% variance of uptake of the radiopharmaceutical in the navicular bone, the region of insertion of the DDFT and the peripheral regions of the distal phalanx. There was a significant difference in uptake of radiopharmaceutical in the region of the navicular bone in horses with foot pain compared to normal horses. There was a large incidence of false positive results related to the region of insertion of the DDFT. Lateral pool phase images appeared more sensitive in identifying potentially important DDFT lesions. There was a good correlation between a positive response to intra-articular analgesia of the distal interphalangeal joint and intrathecal analgesia of the navicular bursa and increased uptake of radiopharmaceutical in the region of the navicular bone in the horses with primary foot pain. It is concluded that quantitative scintigraphic assessment of bone phase images of the foot, in combination with local analgesic techniques, can be helpful in the identification of the potential source of pain causing lameness related to the foot, but false positive results can occur, especially in horses with low heel conformation.

Anesthetics, Local↗
PubMed2001

Scapulohumeral osteoarthritis in 20 Shetland ponies, miniature horses and falabella ponies.

This paper describes the clinical and diagnostic features of 20 cases of scapulohumeral osteoarthritis in Shetland ponies, miniature horses and falabella ponies. The history and clinical signs were similar in all the cases Radiographically they all had consistent changes which consisted predominantly of articular osteophytes and periarticular enthesiophytes. Six of the cases had radiographic evidence of dysplasia of the scapulohumeral joint, although it was uncertain whether this was a primary or a secondary finding. No specific treatment appeared to be advantageous. At follow up, six of the ponies had to be euthanased owing to continuing severe lameness; the other 14 ponies remained lame, but were maintained at pasture by the occasional use of oral non-steroidal anti-inflammatory drugs. No definitive aetiology for the condition was identified, but it is proposed that an underlying dysplasia, or lack of collateral support may predispose the scapulohumeral joint of miniature horse breeds to the disease.

Animals↗
PubMed1996

Infection of the intertubercular bursa in horses: four cases (1978-1991).

OBJECTIVE: To determine the clinical outcome of horses treated for infection of the intertubuercular bursa (infectious bicipital bursitis). DESIGN: Retrospective analysis of case records. ANIMALS: Four horses referred for treatment of infectious bicipital bursitis. PROCEDURE: Medical records of horses that were severely lame on admission were reviewed. RESULTS: In 3 horses, palpation over the bicipital bursa as well as flexion and extension of the scapulohumeral joint were resented. Ultrasonography performed in 1 horse revealed that the bicipital bursa was large and that excessive amounts of fluid containing hyperechoic material were evident within the bicipital bursa. Two horses were treated by the administration of antimicrobial and nonsteroidal antiinflammatory drugs. Both remained lame and failed to resume their former activity. Two horses additionally were treated surgically by means of a partial synovectomy. Both resumed their former activity although a subtle lameness remained in 1 horse. CLINICAL IMPLICATIONS: Partial synovectomy may be useful in the treatment of horses with infectious bicipital bursitis.

Animals↗
PubMed1996

Hypertrophic osteopathy (Marie's disease) in Equidae: a review of twenty-four cases.

The case records of 23 horses and one donkey affected by hypertrophic osteopathy (HO) (Marie's disease) were reviewed. All affected animals presented with limb swellings, which were bilaterally symmetrical and usually involved both fore- and hindlimbs. Associated signs included stiffness/lameness and weight loss. Radiological features included periosteal new bone formation over the diaphyses and metaphyses of affected bones. The metacarpal and metatarsal bones were most frequently affected. Articular surfaces remained free of disease. Seventeen animals were destroyed on humane grounds, 3 horses recovered after successful treatment of the primary disease, 3 horses recovered after symptomatic treatment and one horse was lost to follow-up. Significant primary diseases that were believed to predispose to HO were identified (pre- or post mortem) in 14 cases. In each of these cases, an intrathoracic disease was identified, although co-existing extrathoracic disease was present in 3 cases. Granulomatous inflammatory lesions were present in 9 of these 14 cases. In 4 horses, which underwent necropsy examination, no significant underlying disease was identified.

Animals↗
PubMed1996

Ultrasonography of the equine triceps muscle before and after general anaesthesia and in post anaesthetic myopathy.

The ultrasonographic appearance of the equine triceps muscle of clinically normal horses, before and after general anaesthesia, was investigated and compared with 5 cases of post anaesthetic myopathy. The triceps muscle areas were examined bilaterally using a 7.5 MHz linear array probe in 2 different planes, with each limb both weightbearing and nonweightbearing. The triceps muscles of 4 unanaesthetised horses were scanned twice, 24 h apart. Six horses underwent general anaesthesia and were scanned pre-anaesthesia and at 1 and 24 h intervals after recovery. Blood samples were obtained in the unanaesthetised group at each scan time and, in the anaesthetised group, pre-anaesthesia and at 10 min, 5 and 24 h after recovery. Creatine kinase (CK) and aspartate aminotransferase (AST) concentrations were measured. Anaesthetic details and recovery were related to the ultrasonographic and muscle enzyme findings. Five horses with post anaesthetic myopathy were scanned at intervals after the onset of clinical signs. In normal horses, the triceps muscle appeared ultrasonographically as echoic striations separated by anechoic areas. The fascia dividing muscle bellies was visible as an echoic line. Ultrasonographs obtained with the limb nonweightbearing had no change or a slight overall increase in echogenicity. The scans of control unanaesthetised horses were unchanged on successive days. All anaesthetised horses had uncomplicated anaesthesia and recoveries and did not exhibit any clinical signs of post anaesthetic myopathy. Elevated CK and AST values were found up to 342 and 195%, respectively, of the pre-anaesthetic values but no significant alterations in the ultrasonographic appearance of the muscles were detected. Clinical cases of post anaesthetic myopathy had disruption of the normal ultrasonographic pattern. There was an overall increase in echogenicity with a loss of the normal striated pattern. In 3 cases, there was localised increased echogenicity within the muscle. One of these horses was humanely destroyed for other reasons and histological examination of the affected muscle revealed a necrotic area correlating with the hyperechoic region. Two horses had bilateral involvement of the triceps musculature. Four horses recovered clinically from the myopathy and the ultrasonographic appearance returned to normal except in 1 horse where focal hyperechoic regions remained 10 weeks after the onset of the clinical signs.

Anesthesia Recovery Period↗
PubMed1996

Physiological responses in nonheat acclimated horses performing treadmill exercise in cool (20 degrees C/40% RH), hot dry (30 degrees C/40% RH) and hot humid (30 degrees C/80% RH) conditions.

The aim of the present study was to determine the effect of different environmental conditions on physiological response to exercise. Four winter acclimatised, nonheat acclimated horses of different breeds were exercised at 20 degrees C/40% RH (CD), 30 degrees C/40% RH (HD) and 30 degrees C/80% RH (HH). The exercise test was designed to represent the structure and intensity of a One star Speed and Endurance test (competition exercise test [CET]). All 4 horses were able to complete the full CET (60 min + 30 min active recovery) in CD and HD, but only one horse completed the CET in HH. Two horses were stopped because of pronounced general fatigue and one because of a right atrial temperature (TRA) of 43 degrees C. Oxygen uptake on each phase was not different between CD and HD, but was higher during Phases B, C and D in HH. Mean peak TRA at the end of Phase D was 40.3 +/- 0.2, 41.6 +/- 0.4 and 42 +/- 0.3 degrees C for CD, HD and HH, respectively. Corresponding, mean peak rectal temperatures (TREC) following Phase D were 39.5 +/- 0.1, 40.6 +/- 0.1 and 41.5 +/- 0.1 degree C for CD, HD and HH, respectively. Mean time to peak TREC was 9.3 +/- 1.1 (CD), 7.3 +/- 1.8 (HD) and 10.8 +/- 2.3 (HH) min and was not significantly different between conditions (P > 0.05). Heat dissipation amounted to 83 +/- 1, 73 +/- 2 and 70 +/- 1% of heat production in CD, HD and HH, respectively. Weight loss was significantly correlated with both body surface area (CD r = 0.85; HD r = 0.87; HH r = 0.81) and bodyweight (CD r = 0.97; HD r = 0.93; HH r = 0.94). The greatest weight loss recorded was 4.6% bodyweight in one horse in HD. The mean increase in exercise intensity over the whole CET (in terms of VO2) of HD and HH and HH compared with CD was 5 +/- 3 and 14 +/- 3% higher, respectively. The exercise induced hyperthermia and the reduced capacity for heat dissipation produced partial compensatory responses in minute ventilation (VE), particularly during Phase C, when the horses were trotting. In HD, the increase in VE was achieved mainly through an increase in frequency, whilst in HH it was achieved through an increase in tidal volume (VT). The horses demonstrated a high degree of tolerance to environmental heat load, suggesting a high thermoregulatory capacity. However, for unacclimatised animals exercising in severely hot and humid conditions, performance may be limited.

Acclimatization↗
PubMed1995

Comparison of arthroscopy and arthrotomy for the treatment of osteochondritic lesions in the femoropatellar joint of horses.

Forty-eight horses with osteochondritic lesions of the femoropatellar joint were treated, 23 of them by an arthrotomy and 25 by arthroscopy. Follow-up information was obtained from either the owner or the referring veterinarian by telephone inquiry. There were no statistical differences between the groups of horses undergoing the two procedures with regard to age, sex, breed, the involvement of one or both limbs, the size of the lesion, and the duration of either the surgery or anaesthesia. However, the horses treated by an arthrotomy spent 14.5 days in hospital after the operation whereas those treated by arthroscopy spent only three days. Nineteen of the horses treated by arthroscopy were able to pursue athletic activities and a further five were expected to enter training in the future, whereas only 12 of the horses treated by an arthrotomy were suitable for their intended use (P < 0.05). When the severity of the lesions was considered, the success rate after an arthrotomy deteriorated with increasing severity, whereas the success rate after arthroscopy remained at a high level. Fourteen of the 16 owners of horses treated by an arthrotomy who replied to the question considered that the horses had a palpable scar, a femoropatellar effusion or both, whereas only two of the horses treated by arthroscopy (8 per cent) were considered to have had a poor cosmetic outcome (P < 0.05).

Animals↗
PubMed1995

Aseptic tenosynovitis of the digital flexor tendon sheath, fetlock and pastern annular ligament constriction.

The anatomy of the digital flexor tendon sheath and related tendons and ligaments is described. Diagnosis and management of acute tenosynovitis and long-term tenosynovitis and associated tendon injuries are discussed, as well as the syndrome of stenosis of the fetlock canal (or fetlock annular ligament constriction) and palmar annular ligament constriction. Desmitis of the palmar annular ligament is also described.

Animals↗