Lateral Digital Extensor Tendon Research Articles

Differential Adhesion Selection for Enrichment of Tendon-Derived Progenitor Cells DuringIn VitroCulture

Preplating, a technique used to separate rapidly adherent fibroblasts from the less-adherent progenitor cells, has been used successfully to isolate skeletal muscle-derived stem cells. The objective of this study was to determine if preplating could also be applied to enrich tendon-derived progenitor cells (TDPCs) before monolayer expansion. Cell suspensions obtained by collagenase digestion of equine lateral digital extensor tendon were serially transferred into adherent plates every 12 h for 4 days. TDPC fractions obtained from initial (TPP0), third (TPP3), and seventh (TPP7) preplate were passaged twice and used for subsequent analyses. Growth/proliferation and basal tenogenic gene expression of the three TDPC fractions were largely similar. Preplating and subsequent monolayer expansion did not alter the immunophenotype (CD29(+), CD44(+), CD90(+), and CD45(-)) and trilineage differentiation capacity of TDPC fractions. Overall, TDPCs were robustly osteogenic, but exhibited comparatively weak adipogenic and chondrogenic capacities. These outcomes indicate that preplating does not enrich for tendon-derived progenitors during in vitro culture, and "whole tendon digest"-derived cells are as appropriate for cell-based therapies.

Radiographic and Computed Tomographic Anatomy of the Fetlock, Pastern and Coffin Joints of the Manus of the Donkey (Equus asinus)

The digit of the donkey as a draught animal is commonly susceptible to much affection. The purpose of the present study was to provide a detailed anatomic reference of radiographic and computed tomographic images in conjunction with cross and sagittal sections of the normal fetlock, pastern and coffin joints of the donkey for anatomists, surgeons and veterinary students. Eight adult donkeys of both sexes free from any joints affection were used in our study. The digit of two donkeys had undergone radiographic and computed tomographic scanning; the other donkey’s specimens were used to anatomical dissection and sectional anatomy. In the computed tomography (CT) of the fetlock joint all bone structures of the joint appeared also the soft tissue structures that could be identified and evaluated on the different soft tissue window planes included the common digital extensor tendon, lateral digital extensor tendon, superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), straight, oblique, and cruciate distal sesamoidean and intersesamoidean ligaments. For the pastern joint the structures that can be identified including the proximal phalanx, DDFT and digital cushion. In the coffin joint the collateral sesamoidean ligament (CSL) is difficult to identify on CT images.

MRI FEATURES OF METACARPO(TARSO)PHALANGEAL REGION LAMENESS IN 40 HORSES

Lameness originating from the metacarpo(tarso)phalangeal (MP) joint has a significant effect on the use and athletic competitiveness of a horse. The identification of the cause of lameness originating from the MP joint can be challenging, given the limitations of radiography, ultrasonography, and nuclear scintigraphy. Our purpose was to describe the injury types and incidence in magnetic resonance imaging (MRI) studies from 40 horses with lameness attributable to the MP joint region where it was not possible to reach a clinically plausible diagnosis using other imaging modalities. Horses were examined in a 1.5 T magnet (Siemens Medical Solutions) under general anesthesia. The frequency of occurrence of MR lesions was subchondral bone injury (19), straight or oblique distal sesamoidean desmitis (13), articular cartilage injury and osteoarthritis (eight), suspensory branch desmitis (seven), osteochondral fragmentation (seven), proximal sesamoid bone injury (seven), inter-sesamoidean desmitis (four), deep digital flexor tendonitis (four), collateral desmitis (three), superficial digital flexor tendonitis (two), enostosis-like lesions of the proximal phalanx or MCIII (two), desmitis of the palmar annular ligament (one), desmitis of the proximal digital annular ligament (one), and dystrophic calcification of the lateral digital extensor tendon (one). Twenty-five horses had multiple MR abnormalities. MRI provided information that was complementary to radiography, ultrasonography, and nuclear scintigraphy and that allowed for a comprehensive evaluation of all structures in the MP joint region and a diagnosis in all 40 horses.

SONOGRAPHY OF THE SOFT TISSUE STRUCTURES OF THE CANINE TARSUS

Currently, there are no available anatomic descriptions of the soft tissue structures that are visible with ultrasound in the canine tarsus. Eight cadaver hindlimbs and 10 clinically normal dogs (15-37 kg) were examined with ultrasound to establish which structures could be visualized in normal dogs. The structures always identified included the long digital extensor tendon, the tibialis cranialis tendon, the joint space, and the three bellies of the extensor digitum brevis muscle on the cranial/dorsal aspect of the tarsus. The lateral digital extensor tendon and the peroneus longus tendon were identified as a single structure on the lateral aspect of the tarsus. The caudal/plantar approach allowed identification of the calcaneal tendon, the deep and superficial digital flexor tendons, the plantar ligament, and the lumbricales and interosseus muscles. The medial collateral ligament can be identified on the medial tarsus of larger dogs. This technique has proved useful in the diagnosis of soft tissue injuries of the canine tarsus, and clinical examples of tibialis cranialis tendinopathy, deep digital flexor tendinopathy, fibrosis surrounding the medial collateral ligament and extent of invasion of a tarsal hemangiosarcoma are described.

Evaluation of computed tomographic anatomy of the equine metacarpophalangeal joint

To determine the detailed computed tomography (CT) anatomy of the metacarpophalangeal (MCP) joint in healthy horses. 10 cadaveric forelimbs from 10 adult horses without orthopedic disease. 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. 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. 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.

Extensor tendon lacerations in horses:50 cases (1982-1988)

Summary Medical records of 50 horses with extensor tendon lacerations affecting 53 limbs over 7 years (1982 to 1988) were reviewed to determine the clinical features and prognosis for athletic soundness after treatment. Mean and median ages were 4.8 and 3 years, respectively. Eighty-nine percent of the injuries involved the hind limbs, with approximately equal distribution between the right and left limbs. Hind limb lacerations involved the long digital extensor tendon (28 limbs), lateral digital extensor tendon (3 limbs), or both tendons (16 limbs). Forelimb lacerations involved the common digital extensor tendon (2 limbs), lateral digital extensor tendon (1 limb), or both tendons (3 limbs). Joint involvement was found in 6 cases. Wound management varied according to wound characteristics, financial constraints of owners, and clinician preference. External coaptation consisted of a 3-layered cotton bandage in 33 limbs, splint and cotton bandage in 12 limbs, fiberglass or plaster-of-Paris cast in 5 limbs, and no form of coaptation in 3 limbs. Follow-up information for 40 cases at least 1 year after injury revealed that 29 (73%) horses had returned to athletic soundness, 7 (18%) horses were pasture sound, 3 horses were chronically lame, and 1 horse was euthanatized during treatment because of wound sepsis. Depending on the hind limb tendons involved, return to athletic soundness ranged from 62% (long digital and lateral digital extensor tendons lacerated) to 80% (long digital extensor tendon lacerated) The small number of forelimb lacerations precluded any comparative data. Five of 6 horses with joint involvement returned to athletic soundness. Complications during treatment included wound sepsis/cellulitis, bone sequestra/osteitis of the third metatarsus, and exuberant granulation tissue.

Preliminary study of tendon biopsy in the horse.

A series of experimental tendon biopsies is described. Three biopsies were taken from the lateral digital extensor tendon (LDET) and three from the superficial flexor tendon (SFT). The LDET biopsies resulted in little discomfort whereas the SFT biopsies led to temporary lameness. The tendons were examined histologically up to 99 days after the biopsies were removed. In all of the tendons the defect filled with granulation tissue which subsequently became organised as a longitudinally orientated collagenous scar tissue. In this small series of biopsies the histological effects of the biopsy persisted longer in the SFT than in the LDET. It is concluded that tendon biopsy cannot be advocated for safe routine use in the horse.

Orbital Surgery in Two Horses

The case histories of 2 horses that required surgery within the orbit are described. In 1 horse, severely comminuted fractures of the left facial area and orbit were repaired in 2 stages, the first consisting of elevation and wiring of the depressed fractures. In the second stage, an autogenous tendon graft from the lateral digital extensor tendon of the left front leg was used to reconstruct the orbital floor and elevate the globe in the orbit. In the second horse, a retrobulbar tumor causing exophthalmos and prolapse of the nictitans was removed by creating a bone flap of the zygomatic process of the frontal bone for exposure.

Chronic Tenosynovitis of the Extensor Tendons and Tendon Sheaths of the Carpal Region in the Horse

Seven cases of chronic tenosynovitis affecting the extensor carpi radialis or lateral digital extensor tendon and their sheaths are described. All cases were chronic and in 4 of the cases previous treatment by drainage and local corticosteroid injection had been ineffective. Surgical exploration of 6 cases demonstrated a distinct lesion and specific surgical treatment was carried out.

A method for recording tendon strain in sheep during locomotion.

Strain change in the lateral digital extensor tendon of sheep was measured during locomotion by means of a small metal strain gauge transducer. The strain pattern was correlated with the activity of the muscle and the position of the limb. The main period of tendon strain occurred immediately following a phase of muscle activity as the foot was placed on the ground. A second period of tendon tension occurred as the foot was lifted from the ground. This was again usually associated with a muscular contraction. Daily recordings were taken from 14 animals for about 10 days after implantation of the transducer.