Ankylosis of the distal interphalangeal joint in a horse after septic arthritis and septic navicular bursitis.

A 6-month-old 300-kg Quarter Horse filly was treated for septic arthritis of the distal interphalangeal joint and septic navicular bursitis that developed as a result of a deep puncture to the foot. Initial treatment consisted of establishing ventral drainage for the navicular bursa, lavage of the distal interphalangeal joint, and administration of broad-spectrum antimicrobial drugs and non-steroidal anti-inflammatory drugs. Because of continuing sepsis in the distal interphalangeal joint, subsequent treatment included packing the defect in the bottom of the foot with cancellous bone in an attempt to prevent ascending contamination of the joint, placing the limb in a short limb cast, and inserting a Penrose drain into the joint for passive drainage of septic exudate. The goal of treatment was to encourage ankylosis of the distal interphalangeal joint. Because of the filly's persistent lameness and laxity of the lateral collateral ligament in the contralateral carpus, the palmar nerves of the affected foot were injected with a long-acting local anesthetic at the level of the proximal sesamoid bones to encourage weight-bearing. Ankylosis of the distal interphalangeal joint was complete 9 months after the puncture, but a grade-2 lameness remained and the horse had a varus deformity resulting from ligamentous laxity of the lateral collateral ligament in the contralateral carpus.     

Facilitated ankylosis of the distal interphalangeal joint in a foal

A 3-month-old Quarter Horse colt sustained a penetrating injury over the coronary band on the right forelimb resulting in an articular bone sequestrum and septic arthritis of the distal interphalangeal joint. Despite aggressive treatment for septic arthritis, severe osteoarthritis and ongoing sepsis resulted in persistent lameness. Facilitated ankylosis of the distal interphalangeal joint was performed using a combination of open surgical debridement, placement of an autogenous cancellous bone graft and stabilisation within a transfixation cast. Bony ankylosis of the joint was observed radiographically 7 weeks following surgery. Evaluation of the horse 30 months following surgery revealed complete fusion of the middle and distal phalanges, and the distal sesamoid bone. The horse is pasture sound and is used as a breeding stallion. This report describes the surgical approach and case management employed to achieve facilitated ankylosis as a treatment for unresolved septic arthritis of the distal interphalangeal joint. This is the first report of successful facilitated ankylosis of the distal interphalangeal joint in a foal.     

Osteomyelitis of the axial border of the proximal sesamoid bones in seven horses

Destructive lesions of the axial region of the proximal sesamoid bones were identified by radiography in eight fetlocks and seven lame adult horses. Lameness ranged from 2 to 5 (mean 4; scale 1 to 5) at the time of examination, with a duration of 10 days to two years (mean 5.6 months). Destructive lesions involved both proximal sesamoid bones when examined radiographically and were situated primarily at the level of the mid-body and apical region of the axial borders. Some lesions were cystic, whereas others eroded the axial border more diffusely. Scintigraphy revealed markedly increased activity within the proximal sesamoid bones of the clinically lame limb of four of the five horses examined. In four horses, post mortem computed tomography revealed axial border bone destruction and cavitary lesions within cancellous bone of affected proximal sesamoid bones. Lesions seen by computed tomography were larger than those identified on radiographic examination. Cavitary lesions not seen radiographically were identified in the proximal sesamoid bones of two clinically unaffected fetlocks examined for comparison in two of the seven horses. Evidence of acute, subacute or chronic/reparative osteomyelitis of the axial region of the proximal sesamoid bones was seen in the 10 fetlocks identified as abnormal from radiography or computed tomography. Also, three horses had septic synovitis of the flexor sheath of the clinically affected limb; of these, two had septic arthritis of the fetlock joint.     

Scintigraphic evaluation of metacarpophalangeal and metatarsophalangeal joints in clinically sound horses.

The purpose of this study was to describe the pattern of radiopharmaceutical uptake in the metacarpophalangeal (MCP) and metatarsophalangeal (MTP) (fetlock) joints in clinically sound horses. Scintigraphic images from 29 clinically normal horses were evaluated. All the images were assessed subjectively. The lateral views were assessed quantitatively using vertical line profiles through the center of the joint, and mean ratios of radiopharmaceutical uptake were calculated from regions of interest around the third metacarpal or metatarsal bones, and the proximal phalanx and proximal sesamoid bones. From the vertical line profiles, in the majority of forelimbs (65%) the peak activity of radiopharmaceutical distribution was at the proximal region of the proximal phalanx, with a significantly lower activity within the condyles of the third metacarpal bone. However, in 84% of hindlimbs there was a broader profile peak incorporating the condyles of the third metatarsal bone and the proximal aspect of the proximal phalanx, indicating a more generalized even uptake of radiopharmaceutical across the MTP joint. When the regions of interest were compared between front and hindlimbs, there was no significant difference between proximal phalanx and proximal sesamoid bones, but the distal condyles of the third metacarpal bone of the forelimb had significantly lower radiopharmaceutical activity than hindlimbs (P < 0.04). In lateral images, the mean forelimb ratios tended to be higher in the left MCP joint compared with the right (P = 0.069). In hindlimbs, the mean ratios tended to be higher in the right MTP joint than the left (P = 0.052). There was no significant effect of age.     

Fungal osteomyelitis of the axial border of the proximal sesamoid bones in a horse

CASE DESCRIPTION: A 12-year-old Standardbred gelding was referred for swelling of the right metacarpophalangeal joint. CLINICAL FINDINGS: Ultrasonography of the right metacarpal area revealed hypoechoic areas in the right digital sheath and metacarpophalangeal joint consistent with synovial effusion. Radiography of the right metacarpophalangeal joint revealed lysis of the axial border of the proximal sesamoid bones. Aspergillus fumigatus was detected on fungal culture of synovial fluid. TREATMENT AND OUTCOME: Regional limb perfusion (150 mg of amikacin in 60 mL of saline [0.9% NaCl] solution perfused for 30 minutes) was performed 2 and 4 days after admission. Itraconazole (5 mg/kg [2.27 mg/lb], PO, q 24 h) was administered for approximately 9 weeks. Joint lavage with amikacin (500 mg) in 1 L of saline solution was performed 4 times. Three months after discharge, the owner reported that the horse was mildly lame during trotting but was moving freely and comfortably during all gaits and had gained a considerable amount of weight. Because the osteoarthritis was not expected to improve and because it was recommended that the horse not return to purposeful exercise, the owner decided to retire the horse from racing. CLINICAL RELEVANCE: Various diagnostic imaging methods and fungal cultures are useful for diagnosing fungal osteomyelitis of the axial borders of the proximal sesamoid bones in horses. Fungal osteomyelitis of the sesamoid bones and erosive arthritis should be considered as a differential diagnosis for horses in which corticosteroids have been administered intra-articularly.     

Evaluation of computed tomographic anatomy of the equine metacarpophalangeal joint

OBJECTIVE: To determine the detailed computed tomography (CT) anatomy of the metacarpophalangeal (MCP) joint in healthy horses. SAMPLE POPULATION: 10 cadaveric forelimbs from 10 adult horses without orthopedic disease. PROCEDURES: CT of the MCP joint was performed on 4 forelimbs. In 1 of the limbs, CT was also performed after intra-articular injection of 30 mL of contrast medium (40 mg of iodine/mL). Transverse slices 1-mm thick were obtained, and sagittal and dorsal planes were reformatted with a slice thickness of 2 mm. The CT images were matched with corresponding anatomic slices from 6 additional forelimbs. RESULTS: The third metacarpal bone, proximal sesamoid bones, and proximal phalanx could be clearly visualized. Common digital extensor tendon; accessory digital extensor tendon; lateral digital extensor tendon; superficial digital flexor tendon (including manica flexoria); deep digital flexor tendon; branches of the suspensory ligament (including its attachment); extensor branches of the suspensory ligament; collateral ligaments; straight, oblique, and cruciate distal sesamoidean ligaments; intersesamoidean ligament; annular ligament; and joint capsule could be seen. Collateral sesamoidean ligaments and short distal sesamoidean ligaments could be localized but not at all times clearly identified, whereas the metacarpointersesamoidean ligament could not be identified. The cartilage of the MCP joint could be assessed on the postcontrast sequence. CONCLUSIONS AND CLINICAL RELEVANCE: CT of the equine MCP joint can be of great value when results of radiography and ultrasonography are inconclusive. Images obtained in this study may serve as reference for CT of the equine MCP joint.     

Gross anatomy,computed tomography,magnetic resonance imaging and bone mineral densitometry of the ovine metacarpo/metatarsophalangeal joint

This study was aimed to provide anatomical atlas of the ovine metacarpo/metatarsophalangeal joints using computed tomography (CT) scan and magnetic resonance imaging (MRI), as well as to investigate bone mineral density (BMD) and morphometric features of this joint. The limbs of twenty adult Sanjabi sheep were examined. Imaging was performed using a 16-slice multi-detector CT scanner and a 1.5 Tesla MRI scanner. The obtained images were correlated with corresponding anatomical sections. BMD was measured by Dual Energy X-ray Absorptiometry (DEXA) method. Also morphometric features included distance between metacarpal and metatarsal heads, width of metacarpal and metatarsal head, length, width and the height of the proximal sesamoid bones were measured. In MRI images, compact bones, ligaments and tendons showed less signal intensity (hypointense). The fatty tissue and bone marrow had more signal intensity (hyperintense), but articular cartilage and synovial fluid showed moderate signal intensity. BMD in the left hind limb was significantly higher than other three limbs (p ≤ 0.05). The length of proximal sesamoid bones in left forelimb was higher than right forelimb (p ≤ 0.05). The thickness of proximal sesamoid bones in left limbs was higher than those in their counterparts (p ≤ 0.05). The width of the medial head in the forelimbs was significantly greater than the hind limbs (p ≤ 0.05). The present results might be useful in managing the clinical techniques on this joint. Larger volume of the proximal sesamoid bones and wider medial head in the forelimbs compared to the hindlimbs impel this speculation that the centre of gravity is closer to the forelimbs.     

BIPARTITE PROXIMAL SESAMOID BONES IN YOUNG THOROUGHBRED HORSES

Twelve foals with unusual sesamoid development were found in a population of 107 Thoroughbred foals (60 males, 47 females) over a three year period. Radiographic examination was done at 14 days of age and at 42 day intervals thereafter. The routine administration was of a dorsopalmar view of the proximal sesamoid bones in the left forelimb. Changes of the proximal sesamoid bones were found in 11% of the foals between 14 and 56 days of age. The change was a radiolucent line at the junction of the middle and proximal third of the sesamoid bone. Of those which were observed with sesamoid bone changes, 8 had a normal radiographic appearance at 60 days. In most foals at least 2 or 3 sesamoid bones of the forelegs were affected. In some only 1 sesamoid bone was affected. The changes did not correlate with a clinical joint disorder. However, females seemed to be affected more than males. This condition may be similar to bipartite sesamoid bones described by others and probably a manifestation of secondary ossification centers.     

COMMINUTED FRACTURE OF THE DISTAL SESAMOID BONE AND DISTAL RUPTURE OF THE DEEP DIGITAL FLEXOR TENDON

A 10-year-old show jumper was evaluated for an acute severe lameness (grade 4 of 5) of the right foreleg. During weight bearing, the toe of the affected limb rotated dorsally suggesting rupture of the deep digital flexor tendon (DDFT). Upon radiographic examination of the hoof, a severe erosion at the flexor surface and a parasagittal fracture of the distal sesamoid bone were found. Ultrasonographic examination confirmed rupture of the DDFT. These findings were confirmed on post-mortem examination. Prior to the acute lameness, the horse was treated with corticosteroid injections into the podotrochlear bursa. Repeated intra-bursal injections of corticosteroids as a possible cause for DDFT rupture are discussed as well as the possible association between a degenerative distal sesamoid bone, a distal sesamoid bone fracture and a DDFT rupture.     

Use of autogenous cancellous bone graft for treatment of osteolytic defects in the phalanges of three cattle.

Osteolytic defects were detected radiographically in the distal sesamoid bone of a 16-month-old Bralers heifer, in the middle phalanx of a 14-month-old American Gray Brahman bull, and in the distal phalanx of a 3-year-old American Gray Brahman bull. The articular cartilage was damaged in each animal because of osteolysis or pathologic fracture. After each animal was anesthetized and positioned in lateral recumbency, the lesions were curetted and packed with cancellous bone harvested from the same animal's tuber coxae. Basic postoperative management involved stall rest and immobilization of the graft site with a fiberglass cast (42 to 79 days), after which a support bandage was used for approximately 2 weeks. Recurrence of lameness has not been observed in these animals for 60 months, 58 months, and 21 months, respectively. These cases exemplify the benefit of using an autogenous cancellous bone graft for treatment of severe osteolysis of a digit in cattle.     

A case of sesamoid bone fragmentation in the leg as the cause of lameness in a female Rottweiler

An eight-month-old female rottweiler was presented with a history of intermittent lameness of the right hindlimb of 4 weeks duration. Radiographs showed a fragmentation in two plantar sesamoid bones of the metatarsophalangeal joint. Based on these clinical and radiographic signs sesamoid disease of the 2nd and 7th sesamoid bone in the right hindpaw was diagnosed. The fragmented sesamoids were surgically removed and histologically examined. The treatment was successful and the dog became lamnessfree. Additional radiographs showed fragmentations of sesamoid bones VII of both the forepaws, but they did not cause any lameness.     

Management of bilateral flexural deformity of the metacarpophalangeal joints in three alpaca crias

Three neonatal alpacas were treated for MCP flexural deformities. Two crias responded well to conservative therapy using splints made from fibreglass cast material. One cria with severe deformity failed to respond to conservative treatment but recovered satisfactorily after transection of the suspensory ligament in both legs. It seems that mild cases of flexural deformity of the MCP joint in alpaca crias respond well to conservative therapy but that surgical correction may be required in more severe cases. Sequential transection of the structures limiting extension of the MCP joint may result in fewer complications than previously reported techniques.     

Unusual Polydactylism in a Foal: A Case Report

A 2 month old quarter horse colt had multiple skeletal abnormalities of the left fore limb, including two supernumerary metacarpal bones, two supernumerary carpal bones, abnormal carpal bone development, and a valgus deformity originating at the carpal joint. The largest supernumerary metacarpal bone was removed completely, a portion of the smaller supernumerary metacarpal bone was removed, and the leg was placed in a tube cast. Surgical treatment improved the clinical appearance and prevented further injury to the limb. The carpal joint width remained increased but the carpal valgus deformity partially responded to hemicircumferential periosteal transection. The foal was sound 2 1/2 years after surgery.     

Evaluation of increased subchondral bone density in areas of contact in the metacarpophalangeal joint during joint loading in horses

OBJECTIVE: To quantitatively evaluate contact area under 2 loads and subjectively compare contact areas with subchondral bone (SCB) density patterns in intact metacarpophalangeal joints of horses. SAMPLE POPULATION: 6 forelimbs from horses without musculoskeletal disease. PROCEDURES: Computed tomographic scans of intact metacarpophalangeal joints were analyzed to obtain SCB density measurements. Each limb was loaded on a materials testing system to 150 degrees and 120 degrees extension in the metacarpophalangeal joint, and the joint was stained via intra-articular injection with safranin-O or toluidine blue, respectively. Each joint was disarticulated, and the surface area was digitized. Total articular surface area, contact area, and percentage contact area at each angle were calculated for the distal third metacarpal condyles, the proximal phalanx, and the proximal sesamoid bones. RESULTS: Contact area on the third metacarpal condyles, proximal sesamoid bones, and the proximal phalanx significantly increased with increased load. Areas of contact subjectively appeared to have a higher density on computed tomographic scans. CONCLUSIONS AND CLINICAL RELEVANCE: Areas consistently in contact under higher load were associated with increased SCB density. This supports the idea that the SCB adapts to the load applied to it. As load increased, contact area also increased, suggesting that areas not normally loaded may have a high degree of stress during impact loading. Quantifying how contact in the joint changes under different loading conditions and the adaptation of the bone to this change in normal and abnormal joints may provide insight into the pathogenesis of osteochondral disease.     

Facilitated ankylosis of a juvenile,flexurally deformed,open, luxated and infected metacarpophalangeal joint using an alternative approach

A 4‐day‐old Arabian filly was referred for severe lameness due to a flexurally deformed, open, luxated and infected metacarpophalangeal joint. Arthrodesis was indicated as progressive cartilage destruction and osteomyelitis developed. An alternative arthrodesis technique was employed, which consisted of a loop of cerclage wire running through predrilled holes in a lateromedial direction and dorsal to the central axis of the third metacarpal bone and proximal phalanx, in combination with external coaptation using a half‐limb transfixation cast. Ankylosis was radiographically confirmed after 4 weeks. The foal was discharged from the hospital with a grade 1 out of 5 lameness and a 6–7° valgus deviation of the ankylosed metacarpophalangeal joint. At telephone follow‐up after 18 months, the owner reported persistence of the valgus deviation, soundness at walk, and a slight gait irregularity at trot. The described cerclage wire arthrodesis technique is a relatively simple method for attaining ankylosis that could be considered in similar cases.     

Osteitis of the axial border of the proximal sesamoid bones in horses: eight cases (1993-1999).

OBJECTIVE: To determine clinical, radiographic, and scintigraphic abnormalities in and outcome of horses with septic or nonseptic osteitis of the axial border of the proximal sesamoid bones. DESIGN: Retrospective study. ANIMALS: 8 horses. PROCEDURE: Data collected from medical records included signalment; history; horse use; severity and duration of lameness; results of perineural anesthesia, radiography, ultrasonography, and scintigraphy; and outcome following surgery. RESULTS: Five horses did not have any evidence of sepsis; the other 3 had sepsis of the metacarpophalangeal or metatarsophalangeal joint or the digital synovial sheath. All horses had a history of chronic unilateral lameness. Three of 5 horses improved after diagnostic anesthesia of the metacarpophalangeal or metatarsophalangeal joint; the other 2 improved only after diagnostic anesthesia of the digital synovial sheath. Nuclear scintigraphy was beneficial in localizing the source of the lameness to the proximal sesamoid bones in 4 horses. Arthroscopy of the palmar or plantar pouch of the joint or of the digital synovial sheath revealed intersesamoidean ligament damage and osteomalacia of the axial border of the proximal sesamoid bones in all horses. All 5 horses without sepsis and 1 horse with sepsis returned to their previous uses. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that osteitis of the axial border of the proximal sesamoid bones is a distinct entity in horses that typically is associated with inflammation of the associated metacarpointersesamoidean or metatarsointersesamoidean ligament and may be a result of sepsis or nonseptic inflammation. Arthroscopic debridement may allow horses without evidence of sepsis to return to their previous level of performance.     

Morphologic Radiographic Study of the Proximal Sesamoid Bones of the Forelimb in Thoroughbred Racehorses in Training

The aim of this study was to identify differences in bone shape (height and width) of proximal sesamoid bones (PSB) in 2‐year‐old Thoroughbred racehorses in training. Dorsal 15° proximal‐palmarodistal oblique images of each metacarpophalangeal joint were acquired before the horses started training and at 1 year after the start of exercise and racing. There were no changes in height and width of PSBs induced by training. There was a significant difference of height and width between medial and lateral PSBs. In both forelimbs, the medial PSB was significantly wider and shorter than the lateral PSB. The medial PSB of the right forelimb was significantly wider than that of the left forelimb. These results might explain some limb predilection for fracture of PSBs. The difference in strain pattern between medial and lateral PSBs in different loading conditions needs to be investigated.     

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.     

Locking Compression Plates for Pancarpal Arthrodesis in a Thoroughbred Filly

Objective— To report treatment of a comminuted ulnar carpal (UC) bone fracture associated with carpal instability by pancarpal arthrodesis using 2 locking compression plates (LCP).
Study Design— Case report.
Animals— A 2-year-old Thoroughbred filly.
Methods— An UC fracture and luxation of the proximal row of carpal bones was diagnosed radiographically. Pancarpal arthrodesis was performed with 2 LCP positioned dorsolaterally and dorsomedially and centered over the carpus through a single skin incision. The filly was maintained in a full limb cast for 15 days, followed by a tube cast for 14 days, and subsequently a full limb bandage with caudal splint for 21 days.
Results— Two LCP provided appropriate carpal stability resulting in a pasture sound horse 6 months after surgery. The filly was discharged from the hospital 63 days after surgery, walking well with only a slight mechanical lameness.
Conclusion— Use of 2 LCP applied on the dorsomedial and dorsolateral aspect of the carpus can provide carpal stability for pancarpal arthrodesis.
Clinical Relevance— Excellent stability of the carpal joints can be achieved with 2 LCP.     

Tarsocrural joint luxation in a horse.

A 14-year-old Quarter Horse x Thoroughbred gelding was admitted to the teaching hospital because of inability to bear weight on its right hind limb, associated with a severe deviation of the tarsus. The provisional diagnosis was tarsal joint luxation or fracture. Radiography revealed complete luxation of the tarsocrural joint. The luxation was reduced, using minimal force. The horse was confined to a box stall and was maintained in a full-length hind-limb cast for 33 days. Box stall confinement was continued for 3 months after removal of the cast. On reexamination 18 months after the injury, the horse had only mild lameness (grade 1 of 5), but had marked reduction in the range of motion of the tarsus. Radiography revealed extensive changes indicative of severe degenerative joint disease. The horse was still used occasionally as a light pleasure riding horse and maintained itself on pasture well.