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.     

Scapulohumeral arthrodesis in four Shetland ponies

Four Shetland ponies were presented with severe osteoarthritis of the scapulohumeral joint to the Faculty of Veterinary Medicine of Ghent University over a period of 4 years. Ponies were treated with internal fixation using locking compression plates (LCPs) applied cranially across the scapulohumeral joint. Although two ponies developed mild complications, all ponies were more comfortable in the limb within a few hours following arthrodesis.     

Pantarsal arthrodesis in a pony using a locking compression plate

This report describes a case of pantarsal arthrodesis for the treatment of a comminuted fracture and luxation of the equine tarsus using a locking compression plate (LCP). A 20-year-old, 250-kg Welsh Pony cross presented with a severely comminuted fracture of the right tarsus. A dorsal approach to the tarsus was made and a 14-hole, 5.5-mm LCP was used to achieve arthrodesis. The pony was maintained in a full-limb cast for 30 days post-operatively. The incision healed by primary intention, and no surgical complications developed. The pony maintained excellent use of the limb and returned to pasture soundness.     

Successful treatment of a severely contaminated open metatarsophalangeal joint luxation by arthrodesis

A horse with an open medial luxation of the left metatarsophalangeal joint with extensive cartilage and soft tissue damage and severe contamination of the wound was treated with a two-stage approach. In the first stage, the lesion was cleaned, the luxation was reduced, the wound was sutured and the limb was kept in a cast for a total time of 56 days. In the second stage, an arthrodesis of the affected joint was carried out, using a 13-hole broad 4.5 LCP plate. The limb was then kept in a cast for an additional total time of 56 days. At 70 days after the arthrodesis, the horse was brought in for a final check-up, and only a mechanical lameness remained at that time. No significant complications occurred. Previous case reports on the treatment of metatarso-/metacarpophalangeal luxations include neither cases as severe as the one presented here nor treatment by fetlock arthrodesis. This case illustrates that horses with a complicated, open luxation of the fetlock can be salvaged for breeding purposes.     

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.     

Bilateral distal radial epiphysectomy and pancarpal arthrodesis for correction of complex carpal deformities in an American Miniature horse

A 9‐day‐old American Miniature horse was referred for evaluation and treatment of congenital bilateral carpal deformities. Clinical examination revealed a combination of flexural, angular and rotational deformities affecting both carpi. Radiographic evaluation of both forelimbs revealed malformation of the distal radial epiphysis accompanied by flexural contracture and external rotation of the limb distal to the antebrachial carpal joint. Conservative therapy was attempted with splints and bandages and failed to result in improvement. Surgical intervention was elected and a bilateral distal radial epiphysectomy and pancarpal arthrodesis performed. Fourteen months later the mare was turned out to pasture and ambulating well.     

Nuclear Scintigraphic Evaluation of the Distal Tarsal Region in Normal Horses

Bone-phase scintigraphy is sensitive to the dynamic process of bone modeling and remodeling, which may be adaptive or pathologic. Our knowledge of normal patterns of radiopharmaceutical uptake (RU) is limited, making interpretation of images problematic. It is therefore important to characterize normal patterns of RU at specific sites and relate these to age and exercise, to ensure valid interpretation of images in clinical cases with subtle lesions. This study aimed to characterize patterns of uptake of radiopharmaceutical in the distal tarsal region in clinically normal horses, and to investigate the effects of age and work discipline. Retrospective evaluation of nuclear scintigraphic images of the distal tarsal region of 30 clinically sound, high-level showjumpers and lower-level riding horses was performed. All images were acquired dynamically as a series of 35 two-second frames, which were then motion corrected and summated. The images were assessed using vertical and horizontal profile analysis across the distal tarsal region, and regions of interest comparisons between the distal tarsal region and tibia within each horse. There was a repeatable pattern of RU across the distal tarsal region in both horizontal and vertical directions. There was significantly greater RU on the dorsal compared with plantar aspect, and lateral compared with medial aspect of the distal tarsal region. RU in the right distal tarsal region was significantly greater than in the left. Elite showjumpers had significantly higher RU ratio compared with the lower-level riding horses, but no significant alterations in the pattern of RU were detected.     

Carpal arthrodesis using a minimally invasive approach and locking compression plates: Three cases

Three horses with carpal instability due to comminuted second carpal bone fractures (Cases 1 and 3), fracture of the head of the second metacarpal bone (Case 1) or comminuted fractures of the fourth carpal bone, ulnar and intermediate carpal bones (Case 2) were treated by minimally invasive approach for partial (Cases 1 and 3) or pancarpal (Case 2) joint arthrodesis, using locking compression plates. The joint cartilage was removed by either an arthroscopic approach (middle carpal joint and antebrachiocarpal joint) or a percutaneous drilling technique (carpometacarpal joint). Two or 3 locking compression plates were contoured to the dorsolateral, dorsomedial and dorsoaxial aspects of the carpal joints using a custom‐made tunnelling tool and a minimally invasive tunnelling technique, and the screws were positioned through stab incisions. All cases recovered well, were lame free at the walk, were able to trot and gallop and could be used for leisure and pasture activities (partial carpal arthrodesis) and breeding (pancarpal arthrodesis). Post‐operative x‐rays showed progressive joint fusion after 12 months (Case 1), 5 months (Case 2) and 10 months (Case 3). Case 2 with a pancarpal arthrodesis showed a mechanical lameness at the walk due to the inability to flex the carpus. Carpal flexion after carpometacarpal and middle carpal arthrodesis in Case 1 was calculated to be 42.6° and 44° in Case 3.     

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.     

Proximal interphalangeal arthrodesis in 22 horses

The purpose of this study was to evaluate a new method of internal fixation technique for pastern arthrodesis. Pastern arthrodeses are performed commonly in horses with chronic osteoarthritis of the pastern joint or, in cases of acute traumatic injury to the pastern, in which the weightbearing bony column must be restored. Chronic osteoarthritis of the pastern is a frequent cause of lameness in the equine athlete and is evidenced by chronic lameness localised to the pastern joint, and supported radiographically by periosteal proliferation and loss of joint space. Nonsurgical and surgical treatments have both been described in the literature. Complications following pastern arthrodesis have been reported on several occasions and appear to focus on excessive periarticular exostoses and increased time in a cast due to prolonged time to bony fusion. The hospital records of horses presenting for pastern arthrodesis to the Rood and Riddle Equine Hospital in Lexington, Kentucky, were reviewed and 22 met criteria for inclusion in the study. Horses with chronic osteoarthritis of the proximal interphalangeal joint or horses with an acute traumatic injury to the pastern undergoing pastern arthrodesis with one of the following techniques were included in the study. Horses with severe comminution of the middle phalanx were excluded. Three 5.5 mm cortical bone screws placed in lag fashion alone or in combination with a 4 or 3 hole dynamic compression plate affixed with 4.5 mm cortical bone screws were compared. A lower limb fibreglass cast was applied in all cases. Period in cast, time to return to intended use, complications encountered and outcome were evaluated. Seven of the 8 hindlimbs treated with the combination technique became sound. Three out of 6 of the front limbs treated with the combination technique became sound. Four of the 5 horses with hindlimbs, and one of the 2 with front limbs, treated with screws only returned to their intended use. The type of internal fixation did not appear to influence the overall number of horses returning to the intended level of performance. The period spent in cast and the time to return to soundness were decreased in horses operated on using the combination technique. We concluded that, in the immediate postoperative period, the combination of the parallel screw technique with a dorsally-applied dynamic compression plate provides the most stable and secure fixation, minimising motion, expediting bone remodelling and therefore favouring rapid fusion of that joint.     

Subepiglottic cysts in 15 horses

Subepiglottic cysts (SECs) are an infrequent cause of upper respiratory tract noise and exercise intolerance in horses. They may also be associated with no clinical signs and be an incidental finding during routine upper airway endoscopy. The aim of this study was to assess the effect on performance of horses undergoing surgical removal of SECs. The case records of 15 horses (1995–2009) diagnosed with SECs were retrieved. Eleven (73%) of the 15 horses included in the study were Thoroughbred racehorses. Eleven (73%) of the 15 horses had no preoperative clinical signs related to the SECs, with the remaining 4 (27%) having a respiratory noise (n = 4), nasal discharge (n = 1), difficulty swallowing (n = 1) or a cough (n = 1). Endoscopic examination in the standing horse was diagnostic in 93% (n = 14) of horses. Nine (82%) of the 11 Thoroughbred horses were yearlings, of which only one horse (11%) presented with clinical signs consisting of a respiratory noise and nasal discharge. Four of the 11 (36%) Thoroughbred horses were found to have concurrent epiglottic entrapment. Surgical removal was successful in all cases. Eight of the 11 (73%) Thoroughbred horses in this study raced following SEC removal. The majority of SECs are identified during routine endoscopic examinations and are not associated with clinical signs. The prognosis following surgical removal of SECs is good and future performance does not appear to be affected.     

Tenoscopic-assisted treatment of a solitary caudodistal tibial osteochondroma

Solitary osteochondromas are a relatively infrequent cause of lameness in the horse, most commonly occurring in the caudal distal radial metaphysis, with sparse reports in other locations. Their presence adjacent to a synovial sheath frequently results in intra-thecal tendinous laceration and resultant synovial effusion. Surgical excision in combination with arthroscopic debridement of the tendinous pathology offers the best prognosis for soundness. This report details the successful treatment of a caudodistal tibial osteochondroma using a combination of open surgical excision and tarsal sheath tenoscopy.     

三河马运铁蛋白型的研究

采用聚丙烯酰胺凝胶电泳对 2 5匹三河马血清样品进行了分析。发现 1 2个运铁蛋白表现型 ,即DD ,F2 F2 ,RR ,DF2 ,DH2 ,DR ,F1 R ,F2 H2 ,F2 O ,F2 R ,H2 R和OR。其中F2 F2 ,DF2 和OR所占的比例最高 ,分别为 32 % ,1 6 %和 1 2 % ,其他表现型的比例都小于 8%。运铁蛋白型由 6个共显性常染色体等位基因控制 ,即TfD,TfF1 ,TfF2 ,TfH2 ,TfO 和TfR,其基因频率分别为 0 1 6,0 0 2 ,0 48,0 0 6 ,0 1 0和 0 1 8。基因杂合度 (H)和亲权排除概率 (PE)分别为 0 70和 0 47。