Determination of the anatomic communications among compartments within the carpus, metacarpophalangeal and metatarsophalangeal joints, stifle joint, and tarsus in llamas

OBJECTIVE: To determine the anatomic communications among compartments within the carpus, metacarpophalangeal and metatarsophalangeal joints, stifle joint, and tarsus in llamas. SAMPLE POPULATION: 88 limbs from 22 llamas necropsied because of reasons unrelated to disease of the carpus; tarsus; or metacarpophalangeal, metatarsophalangeal, or stifle joints. PROCEDURE: 1 compartment (randomly assigned) of each joint was injected with blue latex solution. Communication between joint compartments was determined by observation of latex in adjacent compartments following frozen sectioning. RESULTS: Of the 44 carpi, 30 (68%) had anatomic separation between the radiocarpal and middle carpal joints, whereas the remaining 14 (32%) had communication between the radiocarpal and middle carpal joints. In the metacarpophalangeal or metatarsophalangeal joints, medial and lateral joint compartments remained separate in 83 of 88 (94%) joints injected. The tibiotarsal and proximal intertarsal joints communicated in all tarsi examined, whereas 14 of 38 (37%) communicated between the proximal intertarsal and distal intertarsal joints. Communication between the distal intertarsal and tarsometatarsal joints was detected in 17 of 25 (68%) specimens; all 4 tarsal joints communicated in 11 of 42 (26%) specimens examined. Examination of 33 stifle joints that were successfully injected revealed communication between the femoropatellar, medial femorotibial, and lateral femorotibial joints. CONCLUSIONS AND CLINICAL RELEVANCE: These data suggest that it is important to determine the joint communications specific to each llama prior to treatment of septic arthritis. The metacarpophalangeal or metatarsophalangeal joint compartments may be considered separate, although the lateral and medial compartments infrequently communicate along the proximal palmar or plantar aspect.     

Arthrographic Analysis of Communication between the Tarsometatarsal and Distal Intertarsal Joints of the Horse

The intra-articular anatomy of 103 equine tarsi was studied by contrast radiography with image intensification and computerized tomography. There was communication between the tarsometatarsal and distal intertarsal joints in 21 of 55 (38%) interpretable tarsometatarsal arthrograms, and in 11 of 48 (23%) interpretable distal intertarsal arthrograms. The difference was not significant. The volume of contrast agent and the pressure of injection did not correlate with communication. Forced injection caused subcutaneous leakage of contrast medium but not communication. Communication occurred via the tarsal canal and the space between the third and the combined first and second tarsal bones. Injection of the distal intertarsal joint from the dorsomedial aspect of the limb, distal to the palpable distal border of the medial branch of the tendon of the tibialis cranialis muscle and between the central, third, and combined first and second tarsal bones, provided reliable access except in the presence of severe periosteal proliferations.     

Surgical arthrodesis for the treatment of osteoarthrosis of the proximal intertarsal, distal intertarsal and tarsometatarsal joints in 30 horses: a comparison of four different techniques

Over a period of seven years, 30 horses were treated by surgical arthrodesis for lameness resulting from osteoarthrosis of the proximal intertarsal, distal intertarsal and tarsometatarsal joints (bone and occult spavin). Twenty-five horses were affected in one hock only and five were affected bilaterally. Four different techniques for achieving arthrodesis were used. Fourteen out of 18 horses (78 per cent) with involvement of the distal intertarsal and tarsometatarsal joints only and six out of 11 horses (55 per cent) in which the proximal intertarsal joint was also involved became sound following surgery. The status of one other horse, with involvement of the proximal intertarsal joint, is not known.     

Arthrodesis of the Distal Intertarsal and Tarsometatarsal Joints in the Horse

Arthrodesis created by destruction of the articular surfaces of the distal intertarsal and tarsometatarsal joints by repeated insertion of a drill was studied in one limb of each of nine horses. Postoperatively, the horses were housed in box stalls for 8 weeks and then confined to a paddock for 19 weeks. Clinical and radiographic evaluations were performed prior to surgery, immediately following surgery, and at 2,4, 6, 8,10,12,16, 20, and 27 weeks following surgery. There was a statistically significant positive correlation between decreasing degree of lameness and increasing radiographic evidence of bony fusion; fusion of the distal intertarsal and tarsometatarsal joints was present in five horses 27 weeks after surgery. The horses lost weight during the first 8 weeks after surgery. Flexion of the treated tarsal joints was decreased significantly at the end of the experiment.
Complications encountered included fracture of the third tarsal bone (five horses), instability of the tarsus (four horses), septic arthritis (three horses), and diarrhea (four horses).
Arthrodesis, with this method of surgical drilling of the distal intertarsal and tarsometatarsal joints, is not recommended because of severe pain, prolonged convalescence, and high incidence of complications.     

Prevalence of Radiographic Signs of Osteoarthritis in Lusitano Purebred Horses

Radiographic prevalence and correlation of radiographic findings has not been performed in Lusitano Purebred horses. The aim of this study was to (1) evaluate the prevalence of primary osteoarthritis radiographic findings in Lusitano Purebred horses; (2) to assess correlations between radiographic findings in different joints of the same limb and different limbs; and (3) elucidate the effect of age in the radiographic findings. A radiographic protocol of the stifle, tarsi, fetlocks and distal limbs was done in 98 Lusitanos and the classification of the radiographs was performed using a 0-4 scale developed and applied blindly by three veterinarians. The distal interphalangeal, proximal interphalangeal, metacarpophalangeal, metatarsophalangeal, tarsometatarsal, distal intertarsal, proximal intertarsal/, tibiotarsal and femorotibial-patellar joints were evaluated. Most joints presented no abnormal findings or minor abnormal radiographic findings (82.86% grade ≤1). The most affected joint was tarsometatarsal and more severe lesions were found in tarsometatarsal and distal intertarsal. Femorotibial-patellar radiographic changes were rare (2.13%). A strong/moderate correlation was found between contralateral joints with exception hindlimb fetlocks. A moderate correlation was found between fore and hindlimbs for distal limb joints. When analyzing ipsilateral as well as diagonal distal limbs, a strong/moderate correlation was also found. The total score progressed in 0.2 score points per each year of age, revealing that age can be a statistically significant predictor for radiographic changes. Overall, Lusitano horses presented a low prevalence of severe radiographic sings of primary osteoarthritis. Findings in contralateral joints tend to be correlated.     

Use of intra-articular administration of ethyl alcohol for arthrodesis of the tarsometatarsal joint in healthy horses

OBJECTIVE: To evaluate the efficacy and safety of intra-articular administration of ethyl alcohol for arthrodesis of tarsometatarsal joints in horses. ANIMALS: 8 healthy female horses without lameness or radiographic evidence of tarsal joint osteoarthritis. PROCEDURE: In each horse, 1 tarsometatarsal joint was treated with 4 mL of 70% ethyl alcohol and the opposite joint was treated with 4 mL of 95% ethyl alcohol. Lameness examinations were performed daily for 2 weeks, followed by monthly evaluations for the duration of the 12-month study. Radiographic evaluations of both tarsi were performed 1 month after injection and every 3 months thereafter. Gross and histologic examinations of the tarsi were undertaken at completion of the study. RESULTS: Horses had minimal to no lameness associated with the treatments. Radiography revealed that 8 of 16 joints were fused by 4 months after treatment, with significantly more joints fused in the 70% ethyl alcohol group. Fifteen of 16 joints were considered fused at postmortem examination at 12 months. Gross and histologic examinations revealed foci of dense mature osteonal bone spanning the joint spaces. Bony fusion appeared to be concentrated on the dorsolateral, centrolateral, and plantarolateral aspects of the joints. Significant differences were not detected between treatment groups for lameness or pathologic findings. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of ethyl alcohol into the tarsometatarsal joint of healthy horses appeared to facilitate arthrodesis of the joint in a pain-free manner. Results warrant further investigation into the potential use of ethyl alcohol in horses clinically affected with osteoarthritis of the tarsometatarsal and distal intertarsal joints.     

Surgical arthrodesis of distal tarsal joints in 17 horses clinically affected with osteoarthritis

Objective To evaluate the outcome of 17 horses that underwent surgical arthrodesis of the tarsometatarsal and distal intertarsal joints for treatment of lameness due to osteoarthritis.
Design Retrospective clinical study using client-owned animals.
Procedure Horses with hindlimb lameness were diagnosed with osteoarthritis of the distal tarsal joints following relief of lameness after intra-articular anaesthesia or intra-articular corticosteroid injection. Surgery to stimulate ankylosis was performed on 27 hocks by placing 3 diverging 3.2 mm drill holes approximately 3 cm through the tarsometatarsal and distal intertarsal joints from the medial aspect of the limb. The results of surgery were assessed by postoperative examinations, telephone communication with clients and analysis of race results.
Results In 71% of horses, surgery was considered to be successful as determined by clinical examination or telephone communication with clients: six of these horses had unilateral surgery and six had bilateral surgery. This represented 85% (6/7) of horses undergoing unilateral surgery and 60% (6/10) of horses having bilateral surgery. All (8/8) racing Standardbreds and 67% (4/6) of racing Thoroughbreds were considered a success. The average time between surgery and a return to racing was 9.5 months.
Conclusions The surgical technique used here can provide resolution of lameness from osteoarthritis of distal tarsal joints with a success rate similar to other reported surgical arthrodesis techniques that are more invasive and have a greater morbidity.     

Retrospective evaluation of equine prepurchase examinations performed 1991-2000

REASONS FOR PERFORMING STUDY: Prepurchase examinations of horses are used increasingly as a means of evaluating future soundness. Data is lacking in the literature of the radiographic findings and results of the lameness examination of comprehensive prepurchase examinations. OBJECTIVE: To summarise the clinical and radiographic findings of prepurchase examinations and determine if radiographic findings correlated with the lameness examination and sale outcome. METHODS: Records of 510 cases were reviewed, radiographs evaluated and grades assigned the navicular bone, distal phalanx, and tarsus. Follow-up information on the horse status was obtained by telephone interviews for 173 horses. RESULTS: Thoroughbred geldings represented the most common breed and sex, mean age 8 years, mean asking price 12,439.40 dollars, and 52.8% were lame. Radiography was the most common diagnostic procedure performed (61.6%), with views of the front feet requested most often (86.6%) followed by the tarsi (68.1%). Grade 1 was most common for the navicular bone while Grade 2 predominated for the distal phalanx. The number of sound horses decreased as grades became more severe. For the tarsi, Grades 0 and 1 were most common for the proximal intertarsal and distal intertarsal/metatarsal joints, respectively. Horses with significant tarsal changes were still able to compete at their expected level. With respect to the radiographic examination, the mean +/- s.d. grade of the horses which were not lame at follow-up was 1.2 +/- 0.9 for the navicular bone and 15 +/- 0.8 for the third phalanx. The mean +/- s.d. grade of sound horses for the distal intertarsal joint was 0.7 +/- 0.6 and 1.14 +/- 0.8 for the tarsometatarsal joint. Horses for which owner follow-up was available and which had a Grade 3 score were also evaluated. For the navicular bone, 17/31 with a Grade 3 remained in active use at follow-up and for the distal phalanx 21/27 were in active use. For the distal intertarsal and tarsometatarsal joints, 20/21 with a Grade 3 were still in active use. CONCLUSIONS: Prepurchase examinations can have a significant effect on the outcome of the sale. For the navicular bone and distal phalanx, higher grades were associated with lameness. In contrast, higher grades in the tarsus were less likely to be associated with lameness. Warmbloods tended to have more extensive changes in the navicular bone and distal phalanx relative to Thoroughbreds but were not as lame. POTENTIAL RELEVANCE: Radiographic changes detected in the navicular bone, distal phalanx and tarsus should be interpreted with consideration to the clinical examination.     

Chemical arthrodesis of the distal tarsal joints using sodium monoiodoacetate in 104 horses

OBJECTIVE: To evaluate chemical arthrodesis using sodium monoiodoacetate for treatment of degenerative joint disease of the tarsometatarsal and distal intertarsal joints. DESIGN: Retrospective clinical study. METHOD: Horses were diagnosed with degenerative joint disease of one or more of the tarsometatarsal or distal intertarsal joints based on history, lameness examination, radiographic findings and, in some cases, response to intra-articular anaesthesia or medication. Intra-articular injections of sodium monoiodoacetate were performed using 23 gauge needles in the sedated, standing horse. Positive contrast arthrography of the distal intertarsal joint was performed in all horses to evaluate needle placement and the presence or absence of communication with other synovial structures. The mean intra-articular dose of sodium monoiodoacetate was 192 mg. Horses were subject to a graded exercise program commencing 7 to 10 days after treatment. Where possible, follow up lameness examination and radiography was performed at 3, 6, 12 and 24 months after treatment. RESULTS: At 3, 6, 12 and 24 months after treatment, respectively, 0/57, 14/55, 41/50, and 29/34 of horses were sound. At 3, 6, 12 and 24 months after treatment, respectively, 5/55, 24/38, 26/30 and 18/18 of horses had radiographic evidence of ankylosis of treated joints. Post injection pain was marked in 6.7% of horses and significant complications requiring further treatment occurred in 3.8% of horses. CONCLUSIONS: Chemical arthrodesis using sodium monoiodoacetate was an effective treatment method for degenerative joint disease of the distal tarsal joints. The technique was performed in the sedated standing horse and required minimal equipment. Results were comparable to those achieved following surgical arthrodesis. The risk of significant complications was minimised through good technique using an appropriate injection volume and concentration.     

Effect of induced unilateral synovitis of distal intertarsal and tarsometatarsal joints on sagittal plane kinematics and kinetics of trotting horses

OBJECTIVE: To study the effect of unilateral synovitis in the distal intertarsal and tarsometatarsal joints on locomotion, including the compensating effects within and between limbs. ANIMALS: 4 clinically normal horses. PROCEDURE: Gait analyses including kinematics, force plate, and inverse dynamic analysis were performed at the trot before lameness, after which synovitis was induced by injecting endotoxin into the right distal intertarsal and tarsometatarsal joints. Gait analyses were repeated 24 to 30 hours later during lameness. Differences between the stride variables during the 2 conditions (lame and sound) were identified. RESULTS: Tarsal joint range of motion, peak vertical force, and vertical impulse were decreased during lameness. Mechanical deficits included a decrease in negative work performed by the tarsal extensors during the early stance phase and a decrease in positive work by the tarsal extensors during push off. No compensatory changes in work were performed by other joints within the lame hind limb during the stance phase. Vertical impulse in the diagonal forelimb decreased, but there were no significant changes in forces or impulses in the ipsilateral forelimb or contralateral hind limb. CONCLUSION AND CLINICAL RELEVANCE: Results indicate that horses are able to manage mild, unilateral hind limb lameness by reducing the airborne phase of the stride rather than by increased loading of the compensating limbs.     

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).     

Traumatic tarsal luxation repaired without internal fixation in three horses and three ponies

Three horses and three ponies were treated for traumatic luxation of the proximal intertarsal or tarsometatarsal joint. In each case, there were fractures of one or more tarsal bones. Three of the animals had disruption of one of the collateral ligaments. Five animals were treated by closed reduction and external coaptation. One pony was treated by open curettage, a cancellous bone graft, and cast immobilization. No internal fixation was used in any of these animals. From this series of cases, it would appear that closed reduction and external coaption alone is adequate treatment for most cases of tarsal luxation.     

Diagnosis, relative incidence, and probable cause of cunean tendon bursitis-tarsitis of Standardbred horses

A prospective study of the diagnostic results on 25 previously untreated, slightly lame Standardbred horses showed that manipulative tests are of some help in diagnosis. The lameness of each horse was diminished or the horse went lame on the opposite limb after being given an injection of anesthetic in the cunean bursa, and lameness improved more when local anesthetic was injected in the distal intertarsal and tarsometatarsal articulations. In four horses, lesions of the distal articulation of the hock were evident on radiography.     

High field magnetic resonance imaging contributes to diagnosis of equine distal tarsus and proximal metatarsus lesions: 103 horses

Injury of the distal tarsus and proximal metatarsus commonly causes lameness. Magnetic resonance imaging (MRI) allows concurrent assessment of both the distal tarsal joints and suspensory ligament origin, and aids identification of lesions that may otherwise go undetected by other modalities. In this retrospective observational study, the medical records of a veterinary imaging center were searched for MRI exams of the distal tarsus and proximal metatarsus for the years 2012 through 2014. Studies for 125 limbs of 103 horses were identified and retrospectively evaluated by two board‐certified veterinary radiologists. Soft tissue and osseous changes were characterized and graded by degree of severity. The patients’ signalment, lameness severity, and results of diagnostic analgesia were recorded. Osteoarthritic changes of the distal intertarsal and tarsometatarsal joints were the most common findings. Other findings included bone marrow lesions, degenerative changes of the small cuboidal bones, subchondral cystic lesions, and intertarsal desmopathy. Suspensory ligament desmopathy was found in 53% of limbs. Fourty‐seven percent of limbs that responded to analgesia of the proximal suspensory ligament had more severe lesions in the distal tarsus. Bone marrow lesions of the third tarsal bone were the only MRI finding that correlated with grade of lameness in patients for which lameness grade was reported. The grade of lameness has a poor correlation with the severity of lesions found on MRI. The findings support the use of MRI for simultaneous evaluation of the proximal metatarsus and distal tarsus, particularly given the difficulty of lesion localization with diagnostic analgesia.     

Fusion of the distal intertarsal and tarsometatarsal joints in the horse using intraarticular sodium monoiodoacetate

Six normal horses received 3 intra-articular injections of sodium monoiodoacetate (MIA) in the distal intertarsal (DIT) and tarsometatarsal (TMT) joints of one hindlimb. Injections were at three week intervals, and post injection pain was controlled with routine administration of phenylbutazone for five days following each injection. All horses underwent a gradually increasing exercise programme consisting of walking and trotting beginning one week after the first injection and continuing for 24 weeks. All treated joints showed increasingly severe radiographic evidence of degenerative joint disease with time. Clinical signs were mild or absent during exercise. All treated joints showed radiographic and histological evidence of fusion 24 weeks after the first injection. Amount of radiographic fusion ranged from 54.49 per cent to 88.64 per cent of the joint space. Histologically, the joint space that appeared radiographically fused was filled mainly with woven and lamellar bone. Fibrocartilage and fibrous tissue was seen frequently in the transition between fused and unfused areas. Articular cartilage in unfused areas was thin, fibrillated, hypocellular and histochemically showed diminished proteoglycan content. Existing joint space was filled with fibrin and necrotic, acellular chondroid matrix. We conclude that MIA will produce fusion of the DIT and TMT joints of normal horses in 24 weeks, and may offer a relatively easy, inexpensive and non-invasive treatment for distal tarsal osteoarthritis in the horse.     

EVALUATION OF DIFFERENT PROJECTIONS FOR RADIOGRAPHIC DETECTION OF TARSAL DEGENERATIVE JOINT DISEASE IN ICELANDIC HORSES

Radiographs from 196 tarsi in 98 Icelandic horses were evaluated to compare the accuracy of four different projections in detecting radiographic signs of degenerative joint disease in the distal tarsus. The extent and localization of tarsal degenerative joint disease found in one projection when reading all four projections of the same tarsus together was compared with the combined findings from all four projections. The results of reading individual radiographic projections without knowledge of the other three projections was also evaluated. Degenerative joint disease was detected most frequently in the plantarolateral-dorsomedial oblique (P1L-DMO) projection. The location with the highest relative frequency of radiographic findings was the dorsolateral aspect of the centrodistal and tarsometatarsal joints respectively. Radiographic signs of active bone remodelling was detected in 30 (33%) and periarticular osteophytes in 51 (56%) of 91 tarsi with degenerative joint disease.     

ULTRASONOGRAPHIC EVALUATION OF TARSOCRURAL JOINT CARTILAGE IN NORMAL ADULT HORSES

Ultrasonographic examination of the tarsus was performed on four clinically and radiographically normal limbs of adult horses. Particular attention was paid to the articular cartilage surfaces of the trochlear ridges of the talus and the distal intermediate ridge of the tibia. Two separate measurements of articular cartilage thickness were acquired from a longitudinal view at each site. Anatomy was confirmed with post mortem dissection. Ultrasonography was found to be a practical method for imaging the articular cartilage over the trochlear ridges of the talus and distal intermediate ridge of the tibia. The cartilage appeared as a hypoechoic band overlying the hyperechoic subchondral bone. The mean cartilage thickness over the lateral and medial trochlear ridges of the talus and the distal intermediate ridge of the tibia were 0.57 mm, 0.58 mm and 0.7 mm respectively. These measurements may have value for comparison to thickened cartilage and lesions of osteochondrosis and abnormally thinned cartilage of osteoarthritis. Ultrasound examination was not helpful in evaluating the proximal and distal intertarsal and tarsometatarsal joints, the close proximity of the articular surfaces obscured visualization of the articular cartilage.     

Comparison of three methods for arthrodesis of the distal intertarsal and tarsometatarsal joints in horses

OBJECTIVE: To evaluate the effects of diode laser surgery (LS), surgical drilling (SD), and intraarticular sodium monoiodoacetate (MIA) as methods for fusing the distal intertarsal (DIT) and tarsometatarsal (TMT) joints in horses. STUDY DESIGN: Experimental study. ANIMALS: Adult horses (15) without radiographic signs of osteoarthritis (OA) of the DIT and TMT joints. METHODS: Group 1 (n=3) had LS performed bilaterally on DIT and TMT joints; 1 horse was evaluated for 1 week and 2 horses were evaluated for 2 weeks. Group 2 (n=6) had LS on DIT and TMT joints of 1 tarsus and MIA administration into the contralateral DIT and TMT joints and were evaluated for 6 months. Group 3 (n=6) had LS performed on DIT and TMT joints of 1 tarsus and SD of the contralateral DIT and TMT joints and were evaluated for 12 months. Postoperative comfort, lameness, radiography, microradiography, and histology scores were compared using repeated measures ANOVA, and paired or 2 sample t-tests; significance was set at P<.05. RESULTS: LS caused the least postoperative morbidity. In group 2, horses were less lame in 4 LS-treated limbs and 2 MIA-treated limbs at 6 months when compared with the contralateral limb. In group 3, horses were less lame in 5 LS-treated limbs and 1 SD-treated limb at 6 and 12 months compared with the contralateral limb. On microradiography, 11 MIA joints and 2 LS joints had bone bridging the joint at 6 months whereas 8 SD joints and 5 LS joints had bone bridging at 12 months. Significantly more joint space was bridged by bone in MIA- (51.4%) and SD (46.2%)-treated joints compared with LS joints at 6 (30.6%) and 12 (28.5%) months, respectively (P<.05). CLINICAL RELEVANCE: SD and MIA resulted in more bone bridging of the distal 2 tarsal joints, than LS. However, LS seemingly caused less pain and discomfort to horses in the immediate postoperative period; horses were generally less lame in the LS limb. More laser energy may need to be applied to these joints to promote fusion; however, it may also have beneficial effects beyond fusion. Further research on horses with OA of the distal 2 tarsal joints is needed to determine whether LS can cause soundness without facilitating bony fusion.     

Surgical treatment of tarsometatarsal joint luxation in a miniature horse foal

A 2-week-old Miniature Horse foal was referred for evaluation and treatment of a luxated right tarsometatarsal joint. Treatment consisted of closed reduction and internal fixation using two partially threaded Steinmann pins placed in normograde fashion through the tuber calcis into the proximal third metatarsus. Traumatic luxation has been reported to occur in the tarsocrural, proximal intertarsal and tarsometatarsal joints within the equine tarsus. Treatment for luxation of the distal intertarsal joint has not been documented. The treatment method most commonly suggested for tarsal luxation is closed reduction and cast immobilisation. Internal fixation using lag screws and plating has also been described. A combination of internal fixation and external coaptation is thought to achieve maximal stability and allow faster convalescence in cases of tarsal luxation. This case report describes for the first time a technique using two Steinmann pins to achieve successful internal fixation of a traumatic tarsometatarsal joint luxation in a 2-week-old Miniature Horse foal.     

Radiologic and anatomic observations of plantar sesamoid bones at the tarsometatarsal articulations of greyhounds

In Greyhounds, 2 plantar sesamoid bones were identified in radiographs taken of the intact tarsus and also of the tarsometatarsal fibrocartilage, that had been dissected free from the joints. Anatomic dissections defined the precise position of each sesamoid. A prominent sesamoid was present on the lateral side of the tarsometatarsal articulation in 50% of the tarsi; it is proposed that this bone be named the lateral plantar tarsometatarsal sesamoid bone. A smaller bone was detected on the medial side of the tarsometatarsal articulation in 27% of the tarsi; it is proposed that this bone be named the intra-articular tarsometatarsal sesamoid bone.