SOFT TISSUE MASSES IN THE FETLOCK JOINT OF HORSES

SUMMARY Eight cases of sessile, intra-articular soft tissue masses originating from the cranio-dorsal attachment of the capsule of the fetlock joint of horses are presented. In 4 of these cases an osteochondral fracture of the first phalanx was also present. Clinically the condition closely resembled villonodular synovitis; however the microscopic changes did not correspond to those reported. The clinical signs included lameness after exercise, joint effusion and pain on manipulation. The offending masses were surgically resected and their histology indicated a chronic proliferative synovitis. The results of these cases indicate that the condition carries a favourable prognosis.     

The fetlock tunnel syndrome in horses: literature review and retrospective study.]

The annular ligament constriction is characterized by a disproportion between the available space and the contents within the fetlock tunnel. The main symptoms are a persisting lameness, distention of the tendon sheath, a typical "notch" when the fetlock is viewed from the side and a hyperflexion pain in the fetlock. The surgical treatment consists of the transection of the fetlock annular ligament. The conservative management can be considered as a independent therapy or as a preparation for a subsequent desmotomy. The medical records of 75 horses suffering from fetlock tunnel syndrome presented at the Veterinary Surgery Clinic of the University of Zurich were studied. 39 horses with 41 affected limbs were reexamined clinically and ultrasonographically. 70% of the surgical cases and 82% of the conservatively treated cases were judged to be sound. Altogether it can be said that the surgical case group had a success rate of 62% while the conservatively treated group showed a success rate of 58%.     

A randomised, double-blinded, placebo-controlled study on the efficacy of a unique extract of green-lipped mussel (Perna canaliculus) in horses with chronic fetlock lameness attributed to osteoarthritis

Reasons for performing study: Lyophilised products from green‐lipped mussel (Perna canaliculus[LPPC]) are used to orally treat horses with osteoarthritis (OA). However, no randomised, controlled or double‐blinded studies on the efficacy of this treatment in horses have been reported to date. Objective: To investigate the effects of a unique LPPC (Biolane) ¹ in improving clinical signs of OA in the fetlock. Methods: Data were analysed from 26 horses with primary fetlock lameness in a controlled, randomised and double‐blinded, multi‐centre clinical trial. The study design was a partial crossover with a washout period and consisted of 19 horses treated with LPPC and 20 with a placebo. Horses were dosed orally with 25 mg/kg bwt/day LPPC or placebo for 56 days. Efficacy was evaluated by clinical assessment of lameness, passive flexion, pain, swelling and heat in the affected joint. Relationships between variables were analysed using an ordinal logistic model with random effects for horse and horse x treatment according to a modified intention‐to‐treat analysis. Results: Clinical evaluation of horses with a fetlock lameness treated with LPPC showed a significant reduction in severity of lameness (P<0.001), improved response to the joint flexion test (P<0.001) and reduced joint pain (P = 0.014) when compared with horses treated with placebo. Conclusions: The LPPC significantly alleviated the severity of lameness and joint pain and improved response to joint flexion in horses with lameness attributable to OA in the fetlock.     

Osteochondral fragmentation of the plantar/palmar proximal aspect of the proximal phalanx in racing horses

SUMMARY The clinical presentation and outcome of treatment is presented for 26 cases of osteochondral fragmentation of the plantar/palmar proximal aspect of the proximal phalanx. Twenty-three were racing Standardbreds and three were racing Thoroughbreds. The most common reason for presentation was an inability to run straight at high speed. Only eight horses presented for lameness, although on examination 19 were lame. A positive flexion test was recorded in 90% of affected fetlock joints and effusion in 48%. Arthroscopic fragment removal was performed on 23 occasions in 21 horses and arthrotomy in one horse. Of the 16 horses that had returned to racing, 12 had improved their performance, while three showed no improvement, and one was retired for other reasons. In three horses refragmentation occurred after surgery, two of which had improved after initial arthroscopic removal. Degenerative changes within the fetlock joint were detected at surgery in eight horses. Of the four horses treated conservatively, one returned to its previous level of performance temporarily after intra-articular medication, one showed no improvement and two were still resting. Plantar/palmar osteochondral fragmentation of the proximal aspect of the first phalanx is a common cause of low-grade lameness in racing horses, and arthroscopic removal results in improvement in race performance in a high percentage of cases.     

Changes in kinematic variables observed during pressure-induced forelimb lameness in adult horses trotting on a treadmill

OBJECTIVE: To determine whether kinematic changes induced by heel pressure in horses differ from those induced by toe pressure. ANIMALS: 10 adult Quarter Horses. PROCEDURE: A shoe that applied pressure on the cuneus ungulae (frog) or on the toe was used. Kinematic analyses were performed before and after 2 levels of frog pressure and after 1 level of toe pressure. Values for stride displacement and time and joint angles were determined from horses trotting on a treadmill. RESULTS: The first level of frog pressure caused decreases in metacarpophalangeal (fetlock) joint extension during stance and increases in head vertical movement and asymmetry. The second level of frog pressure caused these changes but also caused decreases in stride duration and carpal joint extension during stance as well as increases in relative stance duration. Toe pressure caused changes in these same variables but also caused maximum extension of the fetlock joint to occur before midstance, maximum hoof height to be closer to midswing, and forelimb protraction to increase. CONCLUSION AND CLINICAL RELEVANCE: Decreased fetlock joint extension during stance and increased head vertical movement and asymmetry are sensitive indicators of forelimb lameness. Decreased stride duration, increased relative stance duration, and decreased carpal joint extension during stance are general but insensitive indicators of forelimb lameness. Increased forelimb protraction, hoof flight pattern with maximum hoof height near midswing, and maximum fetlock joint extension in cranial stance may be specific indicators of lameness in the toe region. Observation of forelimb movement may enable clinicians to differentiate lameness of the heel from lameness of the toe.     

Clinical and low field magnetic resonance imaging features of osseous cyst‐like lesions of the proximal sesamoid bones in seven horses

Osseous cyst‐like lesions of the proximal sesamoid bones (PSBs) were diagnosed in 7 horses. The diagnosis was achieved radiographically prior to magnetic resonance imaging (MRI) in only one horse, and in the other 6 horses the diagnosis was made using low field MRI (retrospective evaluation of the radiographs after the MRI revealed ill‐defined radiolucencies of the PSBs in 4 of these horses). The horses ranged in age from 3 to 12 years, and the affected limbs included 3 forelimbs and 4 hindlimbs. The onset of lameness was reported to be sudden in 6 horses and insidious in one, and the duration of lameness at the time of MRI ranged from 0.3 to 11 months. The degree of lameness in the 6 horses with sudden‐onset lameness was moderate to severe. Pain on flexion of the affected metacarpo(tarso)phalangeal (fetlock) joint or exacerbation of the degree of lameness following fetlock flexion was recorded in 4 of the 7 horses. The MRI findings in all cases included a focal high signal intensity lesion (all magnetic resonance sequences) at various locations in one PSB. Both septic and nonseptic aetiologies were identified. Four of the 7 horses were subjected to euthanasia due to persistent lameness, one remained chronically lame and only 2 were able to return to their previous level of exercise.     

New surgical approach to the plantar fetlock joint through the digital flexor tendon sheath wall and suspensory ligament apparatus in cases of concurrent septic synovitis in two cattle

A new surgical approach to the infected fetlock joint is described in two cattle suffering from septic tenosynovitis of the lateral digital flexor tendon sheaths of the right lateral hind-digits with concurrent septic serofibrinous arthritis of the adjoining fetlock joints, caused by penetrating wounds. In both patients, the infected sheaths were opened and the superficial and deep digital flexor tendons were removed. Intraoperatively, a small entry through the fetlock joint capsule was detected, directly distal to the lateral proximal sesamoid bone. The tract was surgically enlarged and a second approach into the plantar fetlock joint pouch was created proximally by making a 3 cm long and 0.5 cm wide incision between the two lateral suspensory ligament branches. This allowed easy access to the plantar joint pouch, removal of fibrin clots and an effective joint lavage using 5L of sterile saline solution. The incisions of the fetlock joint capsules remained unsutured and were drained using soft polyurethane foam to preclude premature closure. The tendon sheath wounds remained unsutured. In both patients, the digital flexor tendon sheath and the fetlock joint were lavaged daily for the following three days. The infection was eliminated in both cattle and both fully recovered without residual lameness.     

Detection of lameness and determination of the affected forelimb in horses by use of continuous wavelet transformation and neural network classification of kinematic data

OBJECTIVE: To investigate continuous wavelet transformation and neural network classification of gait data for detecting forelimb lameness in horses. ANIMALS: 12 adult horses with mild forelimb lameness. PROCEDURE: Position of the head and right forelimb foot, metacarpophalangeal (ie, fetlock), carpal, and elbow joints was determined by use of kinematic analysis before and after palmar digital nerve blocks. We obtained 8 recordings from horses without lameness, 8 with right forelimb lameness, and 8 with left forelimb lameness. Vertical and horizontal position of the head and vertical position of the foot, fetlock, carpal, and elbow joints were processed by continuous wavelet transformation. Feature vectors were created from the transformed signals and a neural network trained with data from 6 horses, which was then tested on the remaining 2 horses for each category until each horse was used twice for training and testing. Correct classification percentage (CCP) was calculated for each combination of gait signals tested. RESULTS: Wavelet-transformed vertical position of the head and right forelimb foot had greater CCP (85%) than untransformed data (21%). Adding data from the fetlock, carpal, or elbow joints did not improve CCP over that for the head and foot alone. CONCLUSIONS AND CLINICAL RELEVANCE: Wavelet transformation of gait data extracts information that is important for the detection and differentiation of forelimb lameness of horses. All of the necessary information to detect lameness and differentiate the side of lameness can be obtained by observation of vertical head movement in concert with movement of the foot of 1 forelimb.     

Kinematics of the hind limb in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and intra-articular administration of anesthetic

OBJECTIVE: To identify hind limb and pelvic kinematic variables that change in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and after subsequent intra-articular administration of anesthetic. ANIMALS: 8 clinically normal adult horses. PROCEDURE: Kinematic measurements were made before and after transient endotoxin-induced lameness of the distal intertarsal and tarsometatarsal joints and after intra-articular administration of anesthetic. Fourteen displacement and joint angle (metatarsophalangeal [fetlock] and tarsal joints) measurements were made on the right hind limb, sacrum, and the right and left tubera coxae. Kinematic measurements were compared by general linear models, using a repeated measures ANOVA. Post hoc multiple comparisons between treatments were evaluated with a Fisher least squared difference test at alpha = 0.05. RESULTS: After lameness induction, fetlock and tarsal joint extension during stance decreased, fetlock joint flexion and hoof height during swing increased, limb protraction decreased, and vertical excursion of the tubera coxae became more asymmetric. After intra-articular administration of anesthetic, limb protraction returned to the degree seen before lameness, and vertical excursion of the tubera coxae became more symmetric. CONCLUSIONS AND CLINICAL RELEVANCE: Increased length of hind limb protraction and symmetry of tubera coxae vertical excursion are sensitive indicators of improvement in tarsal joint lameness. When evaluating changes in tarsal joint lameness, evaluating the horse from the side (to assess limb protraction) is as important as evaluating from the rear (to assess pelvic symmetry).     

Diagnostic imaging of the equine fetlock region using radiography and ultrasonography. Part 1: Soft tissues

The equine fetlock is the joint most commonly associated with lameness. Although the fetlock is regarded as a simple joint, diagnosis of a fetlock disorder can be a challenge and various imaging modalities are routinely used to arrive at an accurate diagnosis. This review describes the principal disorders affecting the soft tissues of the fetlock region and addresses some of the technical aspects involved in taking radiographic and ultrasonographic images of the different soft tissue lesions. A combination of radiography and ultrasonography is still the most commonly used diagnostic approach in clinical practice.     

Epiphysitis in beef cattle fattened on slatted floors.

A syndrome which causes severe lameness and affects the fetlock area of the hind limbs was recently encountered in beef cattle housed on slatted floors. This condition does not appear to have been reported to others. On radiological and pathological examination of the limb, a lesion of epiphysitis was found in the distal epiphysis of the metatarsus. The clinical, radiological and pathological features are reported and discussed.     

Treatment of coxofemoral luxation in a mature Welsh pony by femoral head ostectomy: Long‐term outcome

A 233 kg, 4‐year‐old Welsh pony stallion presented with a unilateral coxofemoral luxation and a history of previous upward fixation of the patella. This condition was surgically managed by femoral head ostectomy using a craniodorsal approach to the luxated coxofemoral joint, without greater trochanteric osteotomy. Immediate improvement in weightbearing was observed after surgery and primary intention healing was recorded. Long‐term outcome, 4 years after surgery, was assessed by radiographic, ultrasonographic and lameness examination. The pony was in good body condition and the initial weight of this patient was restored. Despite fetlock hyperlaxity of the contralateral hindlimb, amyotrophy and mechanical lameness of the affected hindlimb, the pony showed evident comfort without apparent signs of pain and was able to trot and gallop. Bone callus was observed at imaging examination.     

Pathogenesis of three lesions causing lameness of the foreleg in horses

The pathogenesis of three forms of lameness of the foreleg has been presented: fracture of splint bones, strain of the check ligament of the deep flexor tendon, and avulsion fracture of the Mc3 origin of the suspensory ligament. All three lesions have been related to improper positioning of the carpus relative to fetlock rotation at and immediately afterimpact of the foot with the ground.     

Osteochondritis dissecans of the sagittal ridge of the third metacarpal and metatarsal bones in horses

Osteochondritis dissecans of the sagittal ridge of the third metacarpal and metatarsal bones was diagnosed in 8 horses during an 18-month period. Seven of the horses were less than or equal to 2 1/2 years old. Synovial distention of the affected fetlock joints and a pain response to fetlock flexion were typical findings. Lameness predominated in 1 limb at a trot, although fetlock flexion frequently elicited lameness in other affected limbs. Radiography revealed bony lesions (flattening, erosion, or fragmentation) of the sagittal ridge in at least 2 fetlock joints in all horses. The onset of signs was not correlated with the severity of radiographic changes in all horses.     

A Quantitative Review of the Equinalysis System for Equine Locomotion Analysis

Movement analysis techniques allow objective and quantitative assessment of kinematic gait analysis. Consistent repeatability of the kinematic data is essential for such assessments. This study investigated whether the repeatability of a standardized Equinalysis Elite gait analysis system is sufficient to allow its use in clinical evaluation of equine lameness with reliable documentation of individual locomotion patterns. The extent to which examinations on different days affected the results when a standardized protocol was used was investigated. The repeatability of distal limb kinematics in nine sound horses over three successive days at one location was investigated. Measurements were performed at the examination area, for three motion cycles at the walk and trot, in each direction per day. Skin markers were placed on the lateral aspect of the coffin joint, forelimb fetlock joint, hindlimb fetlock joint, carpus, tarsus, elbow, and stifle, at clipped sites marked with a permanent marker. The inter-day repeatability of angular measurements of the carpus, tarsus, forelimb fetlock, and hindlimb fetlock joints was determined. A low degree of inter-day repeatability was found with statistically significant (P ≤ .05) differences between findings on different days, observed in the time-angle diagrams of left and right carpus, tarsus, forelimb fetlock, and hindlimb fetlock joints of all horses, at both walk and trot. The standardized Equinalysis Elite system for gait analysis of distal limb kinematics in the horse did not provide highly repeatable data in this setting.     

Epidemiological study of wastage among racehorses 1982 and 1983

An epidemiological study of wastage among racehorses was conducted in 1982 and 1983 among six stables, five of which were in Newmarket. The basis of the survey was the inability of horses to take part in cantering exercise as a result of injury or disease. The greatest number of days lost to training was caused by lameness (67.6 per cent) and respiratory problems (20.5 per cent). Conditions of the foot (19 pe cent), muscle (18 per cent), carpus (14 per cent), fetlock joints (14 per cent), tendons (10 per cent) and sore shins (9 per cent) were the major reasons for training days being lost in 198 cases in which a positive diagnosis of the site of lameness was made. The results confirm a previous investigation by Jeffcott and others (1982) and suggest that the diagnosis, therapy and prophylaxis of lameness merit a high priority in research efforts to reduce wastage among young racehorses.     

Alternative surgical treatment for synovial ganglion cyst of the digital tendon sheath in one horse

A 6-year-old Highland pony gelding was presented with severe left fore (LF) limb lameness of acute onset. The lameness occurred concomitantly with mild digital flexor tendon sheath (DFTS) effusion and focal painful swelling on the lateral aspect of the LF fetlock region. Clinical examination and diagnostic analgesia localised the lameness to the fetlock region and on ultrasound, a cyst-like structure filled with anaechoic fluid was detected just proximal to the lateral sesamoid bone, at the proximo-lateral aspect of the DFTS and adjacent to the lateral neurovascular bundle. Communication between the cyst-like structure and the DFTS was suspected ultrasonographically and then confirmed with contrast tenography. Tenoscopic examination of the LF DFTS was performed and the communication between the fluid-filled structure and the synovial cavity was detected. The defect in the DFTS wall was enlarged tenoscopically and the lining of the cyst-like structure was debrided. The horse recovered well post-operatively and was back in work with no evident lameness 8 months after surgery. This alternative minimally invasive surgical treatment had an excellent outcome and has the advantage of reducing the risk associated with en bloc resection.     

Treatment of a Cyst-Like Synovial Hernia Associated with the Digital Flexor Tendon Sheath of a 17-Year-Old Pony

The aim of this study is to describe the successful treatment of a synovial hernia associated with the digital flexor tendon sheath (DFTS) in a 17-year-old pony. The pony presented with left forelimb lameness and multiple unusual swellings of the palmar and plantar aspect of the fetlock. The lameness was isolated to a swelling in close proximity to the DFTS of the left forelimb using diagnostic analgesia, and on diagnostic imaging, the swelling was found to be associated with the DFTS. The hernia resolved after percutaneous drainage and intralesional corticosteroids and atropine and pressure bandaging. Reports of synovial hernias in the horse associated with the DFTS are rare. This difference should be considered when presented with cases exhibiting similar clinical signs.     

Diagnostic imaging of the equine fetlock region using radiography and ultrasonography. Part 2: the bony disorders

The metacarpophangeal/metatarsophalangeal (fetlock) joint in the horse is commonly associated with equine lameness and diagnostic imaging is routinely used to investigate disorders of the joint and its surrounding tissues. This review describes the osseous disorders of the fetlock as well as the technical aspects of taking radiographic and ultrasonographic images of the different lesions. In current clinical practice, a combination of radiography and ultrasonography is still the most frequently used approach to arrive at a diagnosis.     

Bilateral lameness in horses a kinematic study

Summary

The kinematic pattern of mild bilateral lameness was studied by inducing a supporting limb lameness in both forelimbs of 11 sound Dutch Warmblood horses. The kinematics of the horses were recorded while they trotted (3.5 m/s) on a treadmill. The locomotion analysis system CODA‐3 was used to determine the temporal stride patterns, limb movements as well as head and trunk movement patterns. The transient lameness model, by which pressure‐induced pain is evoked on the hoof sole, was used. Differences between left and right limbs as well as between the sound and the lame condition were tested using a paired t‐test.

Stride and stance duration did not change significantly (p < 0.05) during bilateral lameness compared to the pattern of sound horses. Diagonal advanced placement changed to an earlier placement of both forelimbs. Fetlock hyperextension decreased also in both forelimbs, while the pro‐ and retraction, hoof impact angle, maximal hoof height, and all hind limb variables remained unchanged. Vertical head and trunk movements tended to decrease, but these changes were not significant.

It was concluded that fetlock hyperextension and diagonal advanced placement indicate locomotor disturbances, but that mild bilateral lameness may be difficult to distinguish from individual patterns in single assessments because of the lack of locomotor asymmetries. Evaluation of these variables at regular intervals may allow an early detection of bilateral lameness, which then could be confirmed by diagnostic local anaesthesia.