Diagnostic and Operative Arthroscopy of the Coxofemoral Joint in Horses

Arthroscopic examination of the hip joint was performed in mature and juvenile horses, using a lateral approach and standard or long instruments depending on body weight. Nine hip joints were examined in three cadavers and four anesthetized horses. The lateral, cranial, and caudal regions of the femoral head and acetabulum were accessible, and, after distraction of the limb, the ligament of the head of the femur and the acetabular notch were also visible. In small horses, the medial regions of the hip joint were visible but were inaccessible in larger horses. Iatrogenic injury to the sciatic nerve or periarticular vasculature was not evident at necropsy examination. Six horses with lameness localized to the hip joint were examined arthroscopically. At surgery, two horses had tearing of the ligament of the head of the femur, two horses had osteochondrosis of the femoral head or acetabulum, and two horses had degenerative joint disease, one associated with a rim fracture of the caudal aspect of the acetabulum and the other of indeterminant origin. Improvement after debridement occurred in one of the horses with partial disruption of the ligament of the head of the femur and in both horses with osteochondrosis. Diagnostic and surgical arthroscopy of the hip can be accomplished in foals and weanlings using standard equipment, but, in adults weighing more than 300 kg, longer instruments are required and the ease of access and the visible extent of the hip joint is considerably reduced.     

Pelvic fractures in horses: 19 cases (1974-1984)

The clinical features of 19 horses with pelvic fractures were reviewed. The most common problem was a grade III or IV unilateral hind limb lameness. The prevalence of fractures was greater in females and horses less than 4 years old. All horses were treated with a combination of analgesic administration and stall rest for 2 to 6 months. Seven of 11 horses (64%) available for long-term follow-up evaluation recovered and 4 of 11 (36%) had no lameness when being ridden. Five of seven (71%) horses with fractures that involved the acetabulum recovered, and 4 (57%) had complete resolution of lameness. No correlation was found between the long-term outcome of the horses and the bone fractured, age of horse, or duration of injury before admission.     

Lameness and poor performance in horses used for team roping: 118 cases (2000-2003)

OBJECTIVE: To determine the types of musculoskeletal problems that result in lameness or poor performance in horses used for team roping and determine whether these problems are different in horses used for heading versus heeling. DESIGN: Retrospective study. ANIMALS: 118 horses. PROCEDURE: Medical records of team roping horses that were evaluated because of lameness or poor performance were reviewed to obtain information regarding signalment, primary use (ie, head horse or heel horse), history, results of physical and lameness examinations, diagnostic tests performed, final diagnosis, and treatment. RESULTS: Among horses evaluated by lameness clinicians, the proportion with lameness or poor performance was significantly greater in horses used for heading (74/118) and lower in horses used for heeling (44/118) than would be expected under the null hypothesis. Most horses examined for poor performance were lame. A significantly greater proportion of horses used for heading had right forelimb lameness (26/74 [35%]), compared with horses used for heeling (7/44 [16%]). Horses used for heading had more bilateral forelimb lameness (18/74 [24%]), compared with horses used for heeling (4/44 [9%]). Horses used for heeling had more bilateral hind limb lameness (3/44 [7%]), compared with horses used for heading (0%). The most common musculoskeletal problems in horses used for heading were signs of pain limited to the distal sesamoid (navicular) area, signs of pain in the navicular area plus osteoarthritis of the distal tarsal joints, and soft tissue injury in the forelimb proximal phalangeal (pastern) region. Heeling horses most commonly had signs of pain in the navicular area, osteoarthritis of the metatarsophalangeal joints, and osteoarthritis of the distal tarsal joints. CONCLUSIONS AND CLINICAL RELEVANCE: Horses used for heading were most commonly affected by lameness in the right forelimb. Horses used for heeling had more bilateral hind limb lameness than horses used for heading.     

Scapulohumeral arthrodesis in miniature horses

OBJECTIVES: To describe surgical arthrodesis of the scapulohumeral joint and to evaluate its efficacy in reducing morbidity associated with severe shoulder dysfunction in miniature horses. STUDY DESIGN: Retrospective study. ANIMALS: Four miniature horses. METHODS: Medical records and radiographs were reviewed for history, physical examination findings, lameness evaluation, radiographic evaluation, surgical techniques, postoperative complications, and outcome. A 10- or 11-hole, 4.5-mm narrow dynamic compression plate and 4.5-mm cortical screws were applied to the cranial surface of the scapula and cranial surface of the humerus after osteotomy of the intermediate tubercle. In most horses, 1 or 2 screws were inserted in lag fashion across the joint, through holes in the plate. RESULTS: Scapulohumeral osteoarthritis was diagnosed radiographically in 4 horses, and 3 horses had concurrent shoulder luxation or subluxation. All horses had grade 3 or 4 lameness before surgery, and most improved by 1 to 2 grades after surgery. Despite complications of implant failure (2 horses), infection (2 horses), scapular fracture (1 horse), and atrophy of the shoulder muscles (1 horse), functional arthrodesis reduced morbidity in all horses. CONCLUSIONS: Scapulohumeral arthrodesis facilitates early return to weight bearing in miniature horses with severe scapulohumeral joint osteoarthrosis. Despite functional gait abnormality, the horses ambulated quite well after surgery. CLINICAL RELEVANCE: Scapulohumeral arthrodesis should be considered for debilitating conditions of the shoulder joint in miniature horses, especially when the intended outcome is breeding or pasture soundness.     

Use of the Cobra Head Bone Plate for Distal Long Bone Fractures in Large Animals A Report of Four Cases

Four long bone fractures with a short distal fragment were repaired with a cobra head bone plate alone (2 cattle) or in combination with a straight, broad dynamic compression plate (2 horses). Three fractures were of the distal femur (1 horse, 2 cattle) and one was of the distal radius (1 horse). The long-term outcome of the three femoral fractures was soundness in one case and mild lameness in two. Although satisfactory bone healing progressed in the horse with the radial fracture, laminitis in the contralateral forelimb necessitated euthanasia at week 6.     

Fractures of the palmar aspect of the carpal bones in horses: 10 cases (1984-2000)

OBJECTIVE: To determine clinical and radiographic findings, treatment, and outcome of horses with fractures of the palmar aspect of the radial carpal bone, with or without concurrent fractures of the palmar surfaces of the other carpal bones. DESIGN: Retrospective study. ANIMALS: 10 horses. PROCEDURE: Medical records were reviewed to obtain information on history, signalment, clinical and radiographic findings, treatment, and outcome. Follow-up information was gathered from owners and referring veterinarians. RESULTS: 7 horses became lame after recovery from general anesthesia for treatment of an unrelated problem. The remaining 3 horses developed a fore-limb lameness after falling (1 horse) or being turned out in a pasture (2 horses). Fractures involved the palmar surface of the radial carpal bone in all 10 horses; in addition, the ulnar carpal bone was affected in 2 horses, the intermediate carpal bone in 2 horses, and the distal aspect of the radius in 4 horses. None of the 4 horses treated nonsurgically returned to work, and 3 were euthanatized because of recalcitrant lameness. In the other 6 horses, fragments were removed surgically. Two were euthanatized because of continued lameness, 1 was euthanatized for other reasons, 2 were sound enough for light work, and 1 returned to athletic work. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that fractures of the palmar aspect of the carpal bones are uncommon in horses. The prognosis appears to be poor for affected horses but may be better for horses that undergo arthroscopic removal of intra-articular fragments.     

Objective determination of pelvic movement during hind limb lameness by use of a signal decomposition method and pelvic height differences

OBJECTIVE: To evaluate pelvic movement over a large number of strides in sound horses and in horses with induced hind limb lameness by applying methods to the pelvis that have been described for evaluating vertical head movement in horses with induced forelimb lameness. ANIMALS: 17 adult horses. PROCEDURE: Horses were filmed while trotting on a treadmill before and after induction of transient mild and moderate hind limb lamenesses. Vertical pelvic movement was measured by a signal decomposition method. The vertical pelvic signal was decomposed into a periodic component (A1) that occurred at half the stride frequency (representing vertical pelvic movement caused by lameness) and another periodic component (A2) that occurred at stride frequency (representing normal vertical pelvic movement of a trotting horse). Vertical pelvic and foot positions were correlated for each stride to compare the difference between the minimum and maximum heights of the pelvis during and after stance of the right hind limb to the minimum and maximum heights of the pelvis during and after stance of the left hind limb. RESULTS: Maximum pelvic height difference and lameness amplitude (A1) differed significantly between sound and mild or moderate hind limb lameness conditions. Mean A1 value for vertical pelvic movement in sound horses was less than that previously reported for vertical head movement. CONCLUSION AND CLINICAL RELEVANCE: Pelvic height differences and signal decomposition of pelvic movement can be used to objectively evaluate hind limb lameness in horses over a large number of strides in clinical and research settings.     

Effect of Betamethasone and Exercise on Equine Carpal Joints With Osteochondral Fragments

Osteochondral fragments were created arthroscopically on the distal aspect of both radial carpal bones in 12 horses. On day 14 after surgery, one middle carpal joint of each horse was injected with 2.5 mL Betavet Soluspan (3.9 mg betamethasone sodium phosphate and 12 mg betamethasone acetate per milliliter) and the contralateral joint was injected with 2.5 mL saline as a control. Intra-articular treatments were repeated on day 35. On day 17, six horses began exercising 5 days per week on a high-speed treadmill. The other six horses were kept in box stalls throughout the study as nonexercised controls. On day 56, all horses were examined clinically and radiographically and then were euthanatized. Samples were obtained for histological, his-tochemical, and biochemical evaluation. Mild lameness was observed in five of the six exercised horses at day 56; four horses were lame in the control limb and one horse was lame in the treated limb. Of the five nonexercised horses evaluated for lameness, two were lame in the control limb, two were lame in the treated limb, and one was lame in both the control and the treated limb. No differences were noted on radiographs or palpation of steroid treated limbs versus control limbs. Firm reattachment of the osteochondral fragment to the radial carpal bone occurred in all but three joints. Gross cartilage damage was not different between steroid-treated joints and joints injected with saline. Histologically, there were no significant detrimental effects of betamethasone with or without exercise, but there was a tendency for more pathological change in treated joints. There was a trend toward decreased glycosaminoglycan staining in steroid treated joints of rested horses, whereas exercised horses had similar glycosaminoglycan staining in treated and control joints. No significant difference in the water content or uronic acid concentration was detected between treated and control joints. Intra-articular betamethasone administration in this carpal chip model was not associated with any significant detrimental effects in either rested or exercised horses.     

Proximal interphalangeal joint arthrodesis in 34 horses using two parallel 5.5-mm cortical bone screws

OBJECTIVE: To report clinical experience with arthrodesis of the proximal interphalangeal joint in horses using two parallel 5.5-mm cortical bone screws placed in lag fashion. STUDY DESIGN: Retrospective, clinical study. ANIMALS: Thirty-four horses, aged 1 to 19 years. METHODS: Medical records for all horses admitted (1991-1997) for pastern arthrodesis using two 5.5-mm ASIF cortical bone screws, in parallel orientation, and placed in lag fashion by use of a combined aiming device to facilitate accuracy were reviewed. Signalment, lameness diagnosis, duration of lameness, limb(s) involved, and outcome were recorded. Criteria for successful outcome were determined as return to previous level of function or future intended athletic use. RESULTS: Thirty-nine proximal interphalangeal joint arthrodeses were performed on 34 horses. One horse was euthanatized in the recovery room and was excluded from data analysis. Successful outcome occurred in 85% of frontlimbs and 89% of hindlimbs. Failure occurred in 5 joints; 1 horse had lameness directly associated with surgery, whereas 4 horses had unrelated lameness. CONCLUSION AND CLINICAL RELEVANCE: Age, breed, and initial disease did not affect outcome. Arthrodesis of the proximal interphalangeal joint by use of two 5.5-mm ASIF cortical bone screws, in parallel orientation, placed in lag fashion by use of a combined aiming device, resulted in sound use of the limb in >85% of the joints with shortened postoperative coaptation.     

Repeatability of subjective evaluation of lameness in horses

Reasons for performing study: Previous studies have suggested that agreement between equine veterinarians subjectively evaluating lameness in horses is low. These studies were limited to small numbers of horses, evaluating movement on the treadmill or to evaluating previously‐recorded videotape. Objectives: To estimate agreement between equine practitioners performing lameness evaluations in horses in the live, over ground setting. Methods: 131 mature horses were evaluated for lameness by 2–5 clinicians (mean 3.2) with a weighted‐average of 18.7 years of experience. Clinicians graded each limb using the AAEP lameness scale by first watching the horse trot in a straight line only and then after full lameness evaluation. Agreement was estimated by calculation of Fleiss' (κ). Evaluators agreed if they picked the same limb as lame or not lame regardless of the severity of perceived lameness. Results: After only evaluating the horse trot in a straight line clinicians agreed whether a limb was lame or not 76.6% of the time (κ= 0.44). After full lameness evaluation clinicians agreed whether a limb was lame or not 72.9% of the time (κ= 0.45). Agreement on forelimb lameness was slightly higher than on hindlimb lameness. When the mean AAEP lameness score was >1.5 clinicians agreed whether or not a limb was lame 93.1% of the time (κ= 0.86), but when the mean score was ≤1.5 they agreed 61.9% (κ= 0.23) of the time. When given the task of picking whether or not the horse was lame and picking the worst limb after full lameness evaluation, clinicians agreed 51.6% (κ= 0.37) of the time. Conclusions: For horses with mild lameness subjective evaluation of lameness is not very reliable. Potential relevance: A search for and the development of more objective and reliable methods of lameness evaluation is justified and should be encouraged and supported.     

Problems associated with the interpretation of the results of regional and intra-articular anaesthesia in the horse

The difficulties associated with the interpretation of the results of regional and intra-articular anaesthesia are discussed with reference to eight lame horses. The clinical and radiographic features of each horse are described, together with the results of anaesthesia. One horse had clinical and radiographic signs consistent with navicular disease but it was not possible to relieve the lameness. Two horses had fractures of bones within the foot but lameness was not improved by palmar (abaxial sesamoid) nerve blocks. One horse had more than one cause of lameness. Four horses had joint pathology but none responded to intra-articular anaesthesia.     

Femoral Capital Physeal Fractures in 25 Foals

The medical records of 25 horses 1 year of age or younger affected with femoral head and neck fractures during an 18 year period were reviewed. Each fracture involved the capital physis. The foals were 11 days to 12 months of age (mean, 5 months). No femoral capital physeal fractures occurred in horses older than 1 year of age during the same period. The history in each case included acute onset of severe unilateral hindlimb lameness, 3 hours to 2 months (mean, 12 days) before presentation. Injuries observed were violent falls, struggles, and kicks. Crepitation, swelling, pain with manipulation or palpation or both, and apparent fracture fragment displacement were inconsistently noted. Tentative clinical diagnoses were confirmed by radiography in 24 foals and by necropsy alone in one foal. Twenty-one foals were euthanatized due to poor prognosis. One foal sent home for stall rest was lost to follow-up. Surgical repair was attempted in three foals. Two fractures were repaired with multiple intramedullary pins and the foals were euthanatized within 2 weeks due to surgical failure and, in one case, contralateral limb breakdown. The third fracture was repaired with a compressing screw and plate device; the animal was pasture sound at month 20.     

Influence of rider on lameness in trotting horses

REASONS FOR PERFORMING STUDY: Equine lameness is commonly evaluated when the horse is being ridden, but the influence of the rider on the lameness has not been documented. OBJECTIVE: To document the effect of 2 riders of different training levels on the vertical movement of the head and croup. METHODS: Twenty mature horses were ridden at trot by an experienced dressage rider and a novice rider, as well as trotted in hand. Kinematic measurements of markers placed on the horse's head and sacral bone were carried out. The asymmetries of the vertical head and sacral bone motion were calculated as lameness parameters and compared with paired t tests. RESULTS: Trotting in hand, 17 horses showed forelimb lameness (1-4/10) and 13 hindlimb lameness (1-2/10). Intra-individually, 11 horses showed significant differences in forelimb lameness and 4 horses showed significant differences in hindlimb lameness when ridden. Over all horses, hindlimb lameness increased significantly under the dressage rider compared to unridden horses. CONCLUSIONS: The presence of a rider can alter the degree of lameness; however, its influence cannot be predicted for an individual horse. POTENTIAL RELEVANCE: In order to evaluate mild lameness, horses should be evaluated at trot both under saddle and in hand. If lameness is exacerbated, a second rider may be helpful; the level of training of the rider should be taken into consideration.     

Lameness due to pain associated with the distal interphalangeal joint: 45 cases

This paper describes the clinical and radiographic features, and response to treatment, of 45 horses which showed lameness that was improved by intra-articular anaesthesia of the distal interphalangeal (DIP) joint. Although many horses had poor conformation of the foot of the lame limb, the majority showed no localising clinical signs suggestive of involvement of the DIP joint. Lameness was usually unilateral. No horse with bilateral lameness responded to treatment. Palmar digital nerve blocks frequently improved or alleviated lameness, although in some horses palmar (abaxial sesamoid) nerve blocks were required to eliminate lameness. This difference in response did not affect response to treatment. Intra-articular anaesthesia of the DIP joint usually resulted in resolution of lameness within 5 mins; a partial improvement in lameness or a slow response were poor prognostic indicators. None of the horses had radiographic abnormalities compatible with navicular disease. Radiographic changes of the distal interphalangeal joint per se were generally detectable only in lateromedial views and were identified in less than one third of the horses. Success rates were low following treatment of cases with radiographic abnormalities. In those with no radiographic abnormalities the response to corrective trimming and shoeing and intra-articular administration of sodium hyaluronate, once or repeatedly, was variable and no parameters could be used to predict the likely outcome. Treatment was successful in approximately 30 per cent of cases. Subsequent treatment of horses which remained lame, by intra-articular administration of polysulphated glycosaminoglycans, was not helpful; only a small proportion became sound following prolonged (nine months) rest.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of magnetic resonance imaging for identifying subchondral bone damage in horses: 11 cases (1999-2003)

OBJECTIVE: To assess the use of magnetic resonance (MR) imaging for identifying subchondral bone damage in the distal limbs of horses. DESIGN: Retrospective study. ANIMALS: 11 horses. PROCEDURE: Medical records of horses with lameness and subsequent evidence of subchondral bone damage as determined by MR imaging were reviewed. Severity and duration of lameness, results of diagnostic local anesthesia and diagnostic testing, surgical and necropsy findings, and treatment were recorded. Outcome was determined by follow-up information obtained from the owner or referring veterinarian. RESULTS: Lameness was localized by physical examination and diagnostic local anesthesia. Lameness was localized to the metacarpophalangeal or metatarsophalangeal joint in 4 horses, distal interphalangeal joint in 5 horses, and tarsocrural joint in 2 horses. The duration of lameness ranged from 2 weeks to 20 months. Magnetic resonance imaging of the affected joints revealed abnormal fluid accumulation within the subchondral bone. None of the abnormalities observed by MR imaging were detected by radiography. Subchondral bone damage was diagnosed in all horses. Arthroscopy of the affected joint was performed in 4 horses. Communication with the articular surface of the affected bone was suspected on the basis of results of MR imaging in 4 horses and was confirmed by arthroscopy in 1 horse and by necropsy in 1 horse. CONCLUSIONS AND CLINICAL RELEVANCE: Magnetic resonance imaging was useful for providing a diagnosis when other imaging techniques did not definitively identify the cause of lameness. Subchondral bone damage was clearly identified by MR imaging and should be considered as a cause of lameness in horses in which radiographic findings are unremarkable.     

Rupture of collateral ligaments in metacarpophalangeal and metatarsophalangeal joints in horses: 17 cases (1999--2005)

OBJECTIVE: To characterize ruptures of collateral ligaments (CLs) in metacarpophalangeal and metatarsophalangeal joints in horses. DESIGN: Retrospective case series. ANIMALS: 17 horses with ruptured CLs. PROCEDURES: Data were obtained from medical records, including signalment, history, clinical signs, ultrasonographic and radiographic findings, treatment, and outcome. Additional follow-up information was obtained from owners or referring veterinarians. RESULTS: The lateral CL was ruptured in 11 horses; the medial CL was ruptured in 6 horses. Ultrasonography revealed ipsilateral rupture of the short and long components of the CL in 11 horses and rupture of only 1 component in 6 horses. No biaxial ruptures were detected, but 9 horses had desmitis of the CL on the nonruptured side of the affected joint. All horses were lame (lameness score range, 2/5 to 4/5). Joint instability was palpable in 9 horses; only 4 horses had episodes of joint luxation. Avulsion fractures were identified radiographically in 6 horses and ultrasonographically in another 2 horses. Stress radiography revealed joint instability in 10 horses. Horses were managed by stall confinement, limb immobilization, and gradual return to exercise. Eight horses returned to riding, 2 resumed breeding, 2 were retired, 2 were euthanized, and 3 were doing well 86 to 139 days after injury. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonographic examination is indicated in horses with acute lameness and swelling at the metacarpophalangeal or metatarsophalangeal joint, particularly when stress radiography cannot be performed or findings are equivocal. Affected horses can be conservatively managed. Prognosis for athletic use may be better than originally believed.     

Idiopathic hopping‐like forelimb lameness syndrome in ridden horses: 46 horses (2002–2014)

There has been no analysis of a hopping‐type forelimb lameness syndrome seen in ridden horses. The objectives of this retrospective study were to describe the clinical features of this syndrome, response to diagnostic analgesia and imaging findings and to document post mortem findings. Clinical records from 2002 to 2014 were reviewed and data concerning signalment, history, lame limb(s), lameness characteristics, response to diagnostic analgesia and diagnostic imaging were recorded. There were 46 horses from 4 to 13 years of age, 6 of which had a history of known or suspected trauma immediately before the onset of reduced performance or lameness. Lameness seen when ridden was characterised by an intermittent shortened cranial phase of the step of the lame forelimb at the trot and marked elevation of the head as the affected limb was protracted, with the horse appearing to ‘hop’ (on the contralateral limb) as if trying to break to canter. When lameness was at its worst horses were unwilling to trot. Three horses showed sporadic severe stumbling. Local analgesia of the affected limb did not improve the lameness and in 16 horses lameness deteriorated. Three of 5 horses showed some improvement (≥2/8 grades) in the hopping‐type lameness after intra‐articular analgesia of the articular process joints of the sixth and seventh cervical vertebrae, ipsilateral to the lame forelimb. Radiographic, ultrasonographic and nuclear scintigraphic examinations were inconclusive. Two of 4 horses responded to treatment with gabapentin. In 3 horses post mortem examination revealed mild lymphocytic inflammation within or around the dorsal root ganglia of the fifth and sixth cervical nerve roots, sixth cervical nerve root or second thoracic nerve root ipsilateral to the lame limb. Idiopathic hopping‐type lameness syndrome in ridden horses may be a pain‐related condition ± a neurological component and currently has a guarded prognosis.     

Osteochondrosis-like lesion of the anconeal process in two horses

A suspected lesion of osteochondrosis dissecans involving the anconeal process of the humeroradial joint (elbow) was found in 2 horses. In horse 1, the lesion was found during routine lameness examination, during which alleviation of the lameness was achieved after intra-articular anesthesia of the elbow. In horse 2, the lesion was found at necropsy. Horse 1 responded satisfactorily to intra-articular treatment with hyaluronic acid. Both horses also had other joints affected with osteochondrosis dissecans.     

Osteolytic lesions of the tuber calcanei in two horses

Two adult horses were evaluated for chronic hind limb lameness. Nonseptic calcanean bursitis with associated focal osteolytic lesions at the point of insertion of the gastrocnemius tendon was diagnosed in each horse by physical and lameness examinations, radiography, ultrasonography, and synovial fluid analysis. Both horses underwent arthroscopic exploration and lavage of the affected bursa, and one horse also underwent surgical debridement of the osseous lesion. Both horses remained lame for 13 months after the surgical procedures. To our knowledge, osseous lesions of the calcaneus in horses with nonseptic calcanean bursitis have not been reported. The flexed proximoplantar-to-distoplantar tangential radiographic view of the calcaneus was essential in localizing the lesions, as was the sonogram in one horse. Arthroscopy provided a thorough evaluation of the bursa and associated tendons. On the basis of the outcome of these 2 horses, the prognosis for complete recovery for horses with this condition appears to be unfavorable. Surgical debridement of the osseous lesion was of no benefit and may have been detrimental.