The Superficial Digital Flexor Tendon (SDFT) in horses is a critical component of the equine musculoskeletal system, primarily responsible for supporting the limb during locomotion. It is located on the back of the leg and extends from the muscle belly in the upper limb to its attachment on the pastern bone in the lower limb. The SDFT is prone to injury due to its high load-bearing function, particularly in performance horses. Injuries to this tendon can result from overuse, sudden trauma, or degenerative changes, leading to conditions such as tendinitis. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, function, injury mechanisms, and rehabilitation strategies for the Superficial Digital Flexor Tendon in horses.
Southwood LL, Stashak TS, Kainer RA, Wrigley RH.To describe a tenoscopic approach to the carpal sheath for desmotomy of the accessory ligament of the superficial digital flexor tendon. Methods: The surgical procedure was developed with use of normal forelimbs from equine cadavers and experimental horses. Methods: Twelve equine cadaveric forelimbs, 4 forelimbs from 2 horses anesthetized for terminal surgical laboratories, and 10 forelimbs from five experimental horses were used. Methods: The limbs were positioned lateral side up with the carpus slightly flexed. After distention of the carpal sheath, a portal was made approximately 2 cm proxi...
Wright IM, McMahon PJ.The paper describes a series of cases with longitudinal tears in the superficial or deep digital flexor tendons within the digital flexor tendon sheath. This appears to be a previously unreported condition. Twenty cases are described, one horse was affected bilaterally. Nineteen defects involved the deep digital flexor tendon and in 2 horses the manica flexoria of the superficial digital flexor tendon was torn. All affected horses were lame and there was marked distension of the digital flexor tendon sheaths. Ultrasonography revealed nonspecific signs of chronic tenosynovitis but not the cause...
Birch HL, Bailey AJ, Goodship AE.Injuries to the superficial digital flexor tendon are common in horses required to gallop and jump at speed. Partial rupture of this tendon usually occurs in the central core of the midmetacarpal region and may be preceded by localised degenerative changes. Post mortem examination of apparently normal equine flexor tendons has revealed an abnormal macroscopic appearance in the central core, characterised by a reddish discolouration. We have previously shown that there is also physical damage to the collagen fibres. In the present study we tested the hypothesis that the abnormal appearance is a...
Crevier-Denoix N, Collobert C, Sanaa M, Bernard N, Joly C, Pourcelot P, Geiger D, Bortolussi C, Bousseau B, Denoix JM.To assess histologic variations of the equine superficial digital flexor tendon (SDFT) according to site and to horse age and activity, and to correlate these data with reported segmental mechanical results. Methods: Superficial digital flexor tendons isolated from 42 horses 0.5 hour to 23 years old. Methods: 7 segments of each SDFT were delimited and submitted for conventional histologic examination. Each segment was examined and graded for fiber undulation, cellularity, number and size of interfascicular connective spaces (ICS), presence or absence of focal and diffuse chondroid metaplasia, ...
Smith RK, Zunino L, Webbon PM, Heinegård D.A protein prominent in guanidine hydrochloride extracts of adult bovine and equine digital flexor tendons was confirmed to be Cartilage Oligomeric Matrix Protein (COMP) by non-reducing and reducing SDS-PAGE, reaction with rabbit anti-COMP polyclonal antiserum on Western blots, trypsin digestion followed by HPLC on a C2/C18 column, and identification of COMP mRNA from tendon on Northern blots. Immunohistochemistry and Western blots of extracts showed COMP to be present in all regions of digital flexor tendons. Equine tendon COMP was purified by ion exchange chromatography and gel filtration and...
Patterson-Kane JC, Wilson AM, Firth EC, Parry DA, Goodship AE.Injury to the core of the mid-metacarpal region of the superficial digital flexor tendon in Thoroughbred racehorses is a very frequent but poorly understood condition. It has been suggested that subclinical changes induced by galloping exercise weaken the collagen in this region of the tendon, predisposing it to rupture. The longitudinally arranged collagen fibrils in tendon follow a planar waveform, termed the crimp. Fibril bundles with a smaller crimp angle fail at a lower level of strain than those with a larger crimp angle. This study tested the hypothesis that a specific 18 month exercise...
Gibson KT, Burbidge HM, Pfeiffer DU.This study documents the results of non-surgical treatment and treatment by superior check desmotomy in Thoroughbred racehorses with superficial digital flexor (SDF) tendonitis. Methods: A prospective study was made of 124 thoroughbred racehorses with unilateral or bilateral SDF tendonitis. Methods: The flexor tendons were assessed by physical and ultrasonographic examination before treatment, and the lesions detected in affected tendons were characterised according to lesion type, length and cross-sectional area. Ninety three horses were managed non-surgically and 31 by superior check desmoto...
Cohen ND, Peloso JG, Mundy GD, Fisher M, Holland RE, Little TV, Misheff MM, Watkins JP, Honnas CM, Moyer W.To describe and compare data from Thoroughbreds that sustained musculoskeletal injuries while racing with data from matched control horses. Methods: Matched case-control study. Methods: 216 Thoroughbreds that sustained a musculoskeletal injury while racing and 532 horses from the same races that were not injured. Methods: Data regarding racing history, race-entrant characteristics, racing events determined by analysis of videotapes of races, and results of prerace physical inspections were determined for all horses. Injured horses were compared with control horses by using conditional logistic...
Patterson-Kane JC, Parry DA, Goodship AE, Firth EC.One of the current concepts with regard to equine superficial digital flexor tendonitis is that cumulative subclinical microscopic damage weakens the structure, predisposing the tendon to partial or complete rupture. This microtrauma is likely to affect the waveform or crimp of the collagen fibrils, which are the units of tensile strength. Collagen fibril crimp morphology characteristics were determined in superficial digital flexor tendons of 18 horses presented for necropsy. Horses were separated into exercised (n = 9) and non-exercised groups (n = 9), based on recent function. Five of the e...
Birch HL, Wilson AM, Goodship AE.Tendons that store energy during locomotion, such as the equine superficial digital flexor tendon (SDFT) and human Achilles tendon, suffer a high incidence of central core degeneration which is thought to precede tendon rupture. Although energy storage contributes to the efficiency of locomotion, tendons are not perfectly elastic and some energy is lost in the form of heat. Recent studies have shown that the central core of equine SDFT reaches temperatures as high as 45 degrees C during high-speed locomotion. In this study, we test the hypothesis that hyperthermia causes tendon cell death and ...
Savelberg HH, Buchner HH, Becker CK.The recovery process of the equine locomotor system after desmotomy of the accessory ligament of the deep digital flexor tendon (AL-DDFT) was investigated by studying the movement patterns and joint moments in 6 horses before and 10 days and 6 months following surgery. Using a modified CODA-3 system the joint angles and angular velocities of the lower limb were assessed in the operated forelimb as before the operation. Simultaneously ground reaction forces were measured and joint moments calculated. At 10 days and 6 months after the operation the carpal joint started to bend earlier in the sta...
Crevier-Denoix N, Collobert C, Pourcelot P, Denoix JM, Sanaa M, Geiger D, Bernard N, Ribot X, Bortolussi C, Bousseau B.The objective of this study was to mechanically characterise superficial digital flexor tendon (SDFT) lesions. Eight pathological SDFTs, isolated from 6 adult horses, were tested in traction until rupture (at 1 mm/s). The stresses and strains simultaneously undergone by each of the 7 segments of a tendon were determined throughout the test, and the modulus of elasticity of each segment was evaluated from the segmental stress-strain curve thus obtained. These mechanical data were compared to those obtained on 10 normal SDFTs. After the test, the tendinous segments were submitted to a histologic...
Gibson KT, Burbidge HM, Anderson BH.To describe clinical findings, ultrasonographic features and outcome of injury to the branches of insertion of the superficial digital flexor (SDF) tendon in horses. Methods: Retrospective study of 14 cases. Methods: Fourteen Thoroughbred horses with tendonitis affecting the branches of insertion of the SDF tendon were examined for lameness, location and amount of swelling, and the presence of other musculoskeletal abnormalities. The flexor tendons were assessed by ultrasonographic examination, and recommendations were made for management of the cases. Outcome was assessed by re-examination of...
Gillis C, Pool RR, Meagher DM, Stover SM, Reiser K, Willits N.To assess tendon morphology and non-reducible crosslink concentration, and associations of these findings with horse age and previously reported mechanical and ultrasonographic findings. Methods: Superficial digital flexor tendon samples were obtained from 23 horses aged 2 to 23 years. The tendons had undergone ultrasonography and were submitted to biomechanical testing in the physiologic range prior to sample acquisition. Methods: Samples were sectioned in a transverse plane; then dorsal, palmar, central, lateral, and medial regions were evaluated for fascicle cross-sectional area (CSA), sept...
Patterson-Kane JC, Wilson AM, Firth EC, Parry DA, Goodship AE.This study was undertaken to test the hypothesis that collagen fibrils, the submicroscopic units of strength in tendon, would hypertrophy in response to a specific defined training programme. Fibril diameters were measured in central and peripheral regions of superficial digital flexor tendon (SDFT) samples from five 18-month-old horses which underwent a subsequent 18 month training programme and 6 age- and sex-matched controls. Central region fibrils from the trained horses had a mass-average diameter (MAD) of 105.3 nm, which was significantly lower (P < 0.01) than that of 131.7 nm for the...
Patterson-Kane JC, Firth EC, Goodship AE, Parry DA.To measure collagen fibril crimp angles and lengths as well as collagen fibril mass-average diameters in central and peripheral regions of the superficial digital flexor tendon of wild horses, to ascertain any age-related changes in either region in the absence of imposed galloping exercise. Methods: Measurements from a random cull of wild horses. Methods: Superficial digital flexor tendon samples were taken from 23 wild horses ranging in age from two to ten years. Methods: Horses were divided into 'young' (< 5 years, n = 10), 'middle-aged' (5 to < 10 years, n = 9) and 'ol...
Patterson-Kane JC, Parry DA, Birch HL, Goodship AE, Firth EC.The superficial digital flexor tendon is the most commonly injured tendon in the racing Thoroughbred. Despite the clinical significance of this structure, only limited data exist regarding normal age-related morphology of the tensile units, the collagen fibrils. The age at which these collagen fibrils become mature in composition and structure may be of importance. Consequently, the association of age and collagen fibril crosslink composition, diameter distribution and crimp morphology in the superficial and deep digital flexor tendons of Thoroughbreds up to and including three years of age ha...
Miller SM, Stover SM, Taylor KT, Zarucco LA.A technique was developed for arthrocentesis of the palmaroproximal pouch of the pastern joint. The landmark for percutaneous puncture is a 'V' shaped depression formed by the palmar aspect of the proximal phalanx (P1) dorsally, an eminence associated with the attachment of the collateral ligaments to P1 and the middle phalanx distally and the insertion of the lateral branch of the superficial digital flexor tendon palmarodistally. Comparison of arthrocentesis between the palmaroproximal approach and the traditional dorsal approach in 8 cadavers and 8 horses demonstrated that the palmaroproxim...
Crevier N, Pourcelot P, Denoix JM, Geiger D, Bortolussi C, Ribot X, Sanaa M.To determine the local variations of mechanical properties of the equine superficial digital flexor tendon (SDFT). Methods: 10 SDFT of adult horses, selected for absence of abnormality. Methods: Needles (with a dark marker at both ends) pinned perpendicularly through each tendon to delimit 7 segments. Each tendon was tested in traction until rupture; test was filmed, using an 8-mm video camera. For each image, the coordinates of the center of mass of each marker and the corresponding force were registered. The third-degree polynomial that best fits the stress-strain curve thus obtained was cal...
Riley CB, Archer FJ, Bailey JV.To compare the effects of different commercial nutrient media and sera on protein synthesis and maintenance of cellular density in cultures of the equine superficial digital flexor tendon (SDFT). Methods: 8 healthy 2- to 4-year-old horses. Methods: First Dulbecco's modified Eagle's medium, Ham's F12 nutrient mixture, RPMI 1640 medium, minimum essential medium with Earle's salts, minimum essential medium with Hanks' salts, and a Dulbecco's modified Eagle's medium/Ham's F12 nutrient mixture with 10% fetal bovine serum (FBS) were compared. Then FBS, fetal equine serum, and donor horse serum, each...
Riemersma DJ, van den Bogert AJ, Jansen MO, Schamhardt HC.Strains in the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), accessory ligament of the deep digital flexor muscle (inferior check ligament [ICL]) and the interosseus medius muscle (suspensory ligament [SL]) in the right forelimb of 5 ponies were measured using mercury-in-silastic strain gauges a few hours after implantation. Tendon strains were recorded at the walk with normal flat shoes, egg-bar shoes, a 7 degrees increased hoof angle accomplished by application of a heel-wedge and a 7 degrees decreased hoof angle using a toe-wedge, consecutively. Ground reactio...
Buchner HH, Savelberg HH, Becker CK.An analysis of joint moments was used to study the biomechanical implications, load redistribution and kinematic pattern following desmotomy of the accessory ligament of the deep digital flexor tendon (AL) in adult horses. Recordings of 6 sound horses were made before and 10 days after desmotomy of the AL of the right forelimb at the walk and the trot. Kinematic recordings of the right forelimb and the left distal forelimb were made using the CODA-3 system. Kinetic recordings of the ground reaction forces in both forelimbs were made using a Kistler force plate simultaneously with the kinematic...
Miles CA, Fursey GA, Birch HL, Young RD.The velocity, attenuation and apparent backscattering coefficient of 6-11-MHz ultrasound were measured in three orthogonal directions in equine deep digital flexor (DDF) and superficial digital flexor (SDF) tendons at 0 degree C. Ultrasonic measurements were examined for correlation with tendon water, collagen, DNA and glycosaminoglycans contents, determined by chemical analyses and with structure observed by scanning electron microscopy. The SDF tendon contained more water, more DNA (i.e., more cells), less collagen and less glycosaminoglycans and exhibited lower velocities and attenuations t...
Gillis C, Sharkey N, Stover SM, Pool RR, Meagher DM, Willits N.Results of studies in human beings and other species have indicated that aging significantly influences the strength, modulus of elasticity, and energy storage ability of tendon. We wanted to determine the effects of aging on the material and ultrasonographic properties of equine superficial digital flexor (SDF) tendon. Ultrasonographic measurements of left forelimb SDF tendon cross-sectional area and mean echogenicity were made in 23 standing horses ranging in age from 2 to 23 years. All horses had not been in work for a minimum of 6 months prior to the study. After euthanasia, left forelimb ...
Gillis C, Meagher DM, Cloninger A, Locatelli L, Willits N.Fifty Thoroughbred horses were examined. All horses had been in race training for a minimum of 4 months before examination and had worked at racing speed; 24 horses had raced. All horses were clinically sound at the time of examination. Ultrasonography was performed, using a 7.5-MHz transducer with built-in fluid offset. Videotaped images of the palmar soft tissue structures were obtained at 4, 8, 12, 16, 20 and 24 cm distal to the base of the accessory carpal bone (DACB). Images were digitized, and each image was calibrated. Values for cross-sectional area (CSA) and mean echogenicity (ME) wer...
Gillis C, Sharkey N, Stover SM, Pool RR, Meagher DM, Willits N.Ultrasonographic cross sectional area (CSA) measurements of equine superficial digital flexor (SDF) tendon were obtained to determine the feasibility of ultrasonography for CSA measurement of tendon in vivo and in vitro. Ultrasonographic measurements were compared with a more traditional CSA measurement method, ink-blot analysis. In addition, values for ultrasonographic SDF tendon mean echogenicity were obtained in vivo and in vitro. The left forelimb SDF tendons of 23 horses were evaluated ultrasonographically. Cross sectional images were acquired at 4-cm intervals distal to the base of the a...
Dyson SJ, Denoix JM.The palmar (plantar) aspect of the pastern is an anatomically complex area and an understanding of this is a prerequisite for accurate diagnosis of injuries in this area. The gross and normal ultrasonographic anatomy are described, and injuries of the superficial and deep digital flexor tendons and the digital flexor tendon sheath, the distal sesamoidean ligaments, and the palmar ligaments of the proximal interphalangeal joint are discussed.
Dik KJ, Leitch M.Contrast radiography provides a clear survey of the size, shape, and location of extratendovaginal fluid-filled cavities, distended bursa, and tendon sheaths and demonstrates intersynovial communication. Ultrasonography effectively demonstrates Achilles tendon injury, slippage of the SDFT off the summit of the calcaneus, assorted ligamentous injuries, and cystic or solid extratendovaginal masses. It will also demonstrate distended bursae and tendon sheaths, but it is not as effective in demonstrating a synovial herniation, or a narrow synovial fistula. Contrast radiography may prove to be the ...
Hogan PM, Bramlage LR.Medical records and lifetime race results were obtained for 61 Standardbred racehorses treated consecutively from 1985 to 1992 with transection of the accessory ligament of the superficial digital flexor tendon (AL-SDF) for tendinitis of one or both forelimbs. A clinical diagnosis of tendinitis was confirmed in all cases by ultrasonographic examination. After surgery, 50 (82%) horses raced and 42 (69%) completed 5 or more starts. Eight horses (13%) failed to start and/or complete 5 or more races due to a recurrence of tendinitis. Six (10%) horses did not start and/or complete 5 or more starts ...
Buchner HH, Savelberg HH, Becker CK.An analysis of joint moments was used to study the biomechanical implications, load redistribution and kinematic pattern following desmotomy of the accessory ligament of the deep digital flexor tendon (AL) in adult horses. Recordings of 6 sound horses were made before and 10 days after desmotomy of the AL of the right forelimb at the walk and the trot. Kinematic recordings of the right forelimb and the left distal forelimb were made using the CODA-3 system. Kinetic recordings of the ground reaction forces in both forelimbs were made using a Kistler force plate simultaneously with the kinematic...
Smith RKW, Schramme MC.Superficial digital flexor tendinopathy is one of the most common orthopedic soft tissue injuries in horses. The veterinary challenge for this condition is less related to identifying the presence of the injury (as it is usually readily evident clinically) but more related to improving the healing process so that the healed tendon is more like normal tendon in biology and function in order to reduce reinjury, which is the key adverse consequence of the injury. Diagnostic imaging has improved in recent years to aid with treatment choices and monitoring the healing process.
Clayton HM, Schamhardt HC, Willemen MA, Lanovaz JL, Colborne GR.To determine whether analysis of net joint moments and joint powers is a suitable technique for evaluation of mechanics and energetics of lameness in horses and to measure effects of superficial digital flexor tendinitis. Methods: 6 sound horses. Methods: Horses were evaluated before (sound evaluation) and after (lame evaluation) induction of superficial digital flexor tendinitis in 1 forelimb by injection of collagenase. Recordings were made with an optoelectronic system and a force plate as horses trotted. Net joint moments and joint powers in the sagittal plane at each joint in the forelimb...
Chesen AB, Dabareiner RM, Chaffin MK, Carter GK.To determine clinical signs, ultrasonographic findings, and outcome of horses with tendinitis of the proximal portion of the superficial digital flexor tendon (SDFT; group A horses) and to compare signalment, horse use, and outcome in these horses with that of horses with tendinitis of the midmetacarpal region of the SDFT (group B horses). Methods: Retrospective case series. Methods: 12 group A horses and 22 group B horses. Methods: Medical records were reviewed for signalment, horse use, and outcome information; data for group A horses also included severity of lameness, diagnostic results, a...
Shoemaker RS, Bertone AL, Mohammad LN, Arms SW.Effects of longitudinal compression before and after transection of the accessory ligament of the superficial digital flexor (SDF) muscle were measured in eight equine cadaver forelimbs. When compression was increased from 890 N to 3115 N, the metacarpophalangeal (MCP) and carpal joints hyperextended 20 degrees and 4 degrees, respectively, and strain in the SDF and deep digital flexor tendons was increased 3.5% and 1.4%, respectively. The accessory ligament did not elongate. Immediately after transection of the accessory ligament at 3115 N load, a 2.8 mm gap formed between the transected ends ...
Hill AE, Blea JA, Arthur RM, McIlwraith CW.Private-practice racetrack veterinarians in southern California recorded non-fatal injuries meeting defined criteria in Thoroughbreds for 1 year. Injury incidence was 2.29 injury events per 100 horse-months, which was lower than other studies where trainer reported injury data were collected. Of 477 injuries recorded, 344 (72.1%) were acute and 133 (27.9%) were chronic. Fractures were common (47.6% of injuries), with stress fractures accounting for 14% of injuries. Superficial digital flexor tendonitis and suspensory ligament desmitis accounted for 15.3 and 11.5% of injuries, respectively. Agr...
Lin YL, Brama PA, Kiers GH, van Weeren PR, DeGroot J.The objectives of the present study were to test the hypotheses that: (1) the composition of the extracellular matrix of the equine superficial digital flexor tendon (SDFT) shows great functional similarities with articular cartilage, i.e. that significant differences exist in biochemical composition of differently loaded areas (which in the case of tendons may be more apparent as tendon shows more obvious differences than cartilage); and (2) that, as in articular cartilage, no substantial alterations in biochemical composition take place during ageing once adulthood has been attained. Tendon ...
Takahashi T, Mukai K, Ohmura H, Aida H, Hiraga A.The purpose of this study was to create a lower forelimb model of the Thoroughbred horse for measuring the force in the superficial and deep digital flexor tendons (SDFT and DDFT), and the suspensory ligament (SL) during a trot. The mass, centers of gravity, and inertial moments in the metacarpus, pastern, and hoof segments were measured in 4 Thoroughbred horses. The moment arms of the SDFT, DDFT, and SL in the metacarpophalangeal (fetlock) and distal interphalangeal (coffin) joints were measured in 7 Thoroughbred horses. The relationship between the fetlock joint angle and the force in the SL...
Dik KJ, Leitch M.Contrast radiography provides a clear survey of the size, shape, and location of extratendovaginal fluid-filled cavities, distended bursa, and tendon sheaths and demonstrates intersynovial communication. Ultrasonography effectively demonstrates Achilles tendon injury, slippage of the SDFT off the summit of the calcaneus, assorted ligamentous injuries, and cystic or solid extratendovaginal masses. It will also demonstrate distended bursae and tendon sheaths, but it is not as effective in demonstrating a synovial herniation, or a narrow synovial fistula. Contrast radiography may prove to be the ...
Kasashima Y, Kuwano A, Katayama Y, Taura Y, Yoshihara T.Six live horses with various stages of acute to chronic superficial digital flexor (SDF) tendinitis were examined using magnetic resonance imaging (MRI). In each case, MRI findings were compared to the corresponding ultrasonographic (USD) and histologic findings, to establish the usefulness of MRI. In the acute cases, lesions characterized by hemorrhage were well defined as high signal intensity on MRI and hypoechoic regions on USD. Chronic tendon fibrosis was slightly hyperechoic and difficult to distinguish from the normal tendon tissue around the original injury by using USD. In contrast, M...
Watanabe T, Hosaka Y, Yamamoto E, Ueda H, Tangkawattana P, Takehana K.The Golgi tendon organ (GTO) is an encapsulated fusiform mechanoreceptor siding in the musculo-tendinous junction of many animal species. Inhibitory function of afferent nerve fibers distributed from nearby motor units, the organ responds to active tension exerted onto the muscle. The morphological features of the equine GTO have not yet been elucidated. Additionally, there is some controversy regarding to the existence of the GTO in the equine superficial digital flexor tendon (SDFT). Therefore, immunohistochemistry and immunoelectron microscopy using alcian blue (pH 2.5) staining and the sil...
Keg PR, van den Belt AJ, Merkens HW, Barneveld A, Dik KJ.The influence of regional nerve blocks on lameness resulting from tendon injury was studied in six horses. Tendonitis was induced in the midmetacarpal region of the Superficial Digital Flexor Tendon (SDF), Deep Digital Flexor Tendon (DDF) and the Suspensory Ligament (SL) through collagenase injections. The results were evaluated through sequential clinical examinations, ultrasonographic imaging and kinetic gait analysis (force plate) during a period of 144 days post injury and subsequently compared with gross and microscopic findings. The lameness corresponding to the SDF and DDF tendon lesion...
Rocconi RA, Sampson SN.To define a method for the basilar sesamoidean approach (BSA) to the digital flexor tendon sheath (DFTS) in horses and compare it with the axial sesamoidean approach (ASA) for DFTS synoviocentesis and injection. Methods: Evaluation study. Methods: 12 healthy adult mares without evidence of abnormalities related to the lower limbs. Methods: Each horse had 1 forelimb and 1 hind limb assigned to each DFTS approach (basilar vs axial, relative to the proximal sesamoid bones) in a Latin square design. The order of horses and of limb injection for each horse was randomly selected. All procedures were...
Smith RL, Murphy DJ, Day RE, Lester GD.To test single cycle to failure tensile strength characteristics of 6 suture material-pattern combinations in equine superficial digital flexor (SDF) tenorrhaphy, specifically to compare a 10-strand modification of the Savage core suture technique with the 3-loop pulley technique. Methods: Ex vivo mechanical experiment comparing 3 different suture patterns with 2 different materials. Methods: Forelimb and hindlimb SDF tendons (n=48) harvested from adult Thoroughbred and Standardbred horses of mixed age and gender. Methods: Six suture material-pattern combinations were evaluated: (1) 10-strand ...
Fulton IC, MacLean AA, O'Rielly JL, Church S.Bilateral superior check ligament desmotomy was performed on 31 Thoroughbred and 17 Standardbred horses as the sole method of treatment for superficial digital flexor tendonitis. Horses resumed racing between 6 and 19 months after surgery. Horses that were able to compete in 5 or more races without injury to the tendon again were considered to have had a successful return to racing. Twenty-five Thoroughbreds were suitable for later study and 13 of these (52%) raced on 5 or more occasions. Fifteen Standardbreds were suitable for later study and 10 of these (66%) raced on 5 or more occasions. Wi...
Khairoun A, Hawkins JF, Moore GE, Lescun TB, Adams SB.Superficial digital flexor tendinitis (SDFT) and proximal suspensory desmitis (PSD) are common causes of lameness in horses. Current treatment options include rest, controlled exercise, administration of anti-inflammatories, intralesional injections, surgery, and electrohydraulic shock wave therapy (ESWT). ESWT is safe, noninvasive, and is used to treat a variety of musculoskeletal abnormalities. Medical records between 2010 and 2021 were reviewed. Horses were separated into two categories: (group 1: ≥ 3 ESWT treatments; group 2: < 3 ESWT treatments). Our objective was to examine the effe...
Mc Nally TP, Slone DE, Hughes FE, Lynch TM.To describe a tenosynoviotomy technique for treatment of sepsis of the digital flexor tendon sheath (DFTS) in horses and report long-term outcome. Methods: Case series. Methods: Horses (n = 9). Methods: Horses were positioned in lateral recumbency with the affected limb uppermost. A linear incision was made just lateral to the mesotenon beginning 5 cm proximal to the apices of the proximal sesamoid bones, extending 2 cm distal to the bifurcation of the superficial digital flexor tendon (SDFT). The incision was continued through the skin, subcutaneous tissue, palmar/plantar annular ligament, an...
Micklethwaite L, Wood AK, Sehgal CM, Polansky M, Dowling BA, Dart AJ, Rose RJ, Hodgson DR.To determine whether quantitative analysis of sonographic brightness could be used to detect healing of an induced injury of the superficial digital flexor tendon in horses and whether rate of healing was influenced by equine recombinant growth hormone. Methods: 8 clinically normal Standardbreds. Methods: A localized injury was created in the left and right superficial digital flexor tendons of each horse by injection of 2,000 units of collagenase. After injury, 4 horses received equine recombinant growth hormone, a possible promoter of tendon healing. Sonographic images (7.5 MHz) of the flexo...
Jordana M, Cornillie P, Oosterlinck M, Simoens P, Pille F, Martens A.During endoscopy (tenoscopy) of the distal aspect of the equine digital flexor tendon sheath (DFTS), the digital manica flexoria can be visualized connecting the distal branches of the superficial digital flexor tendon. However, this structure has been inconsistently described and variably named in the veterinary literature. The objectives of this study were to describe the presence, configuration and variability of the digital manica flexoria in the equine distal limb. Dissection of 144 equine cadaveric limbs revealed the presence of this structure in all the feet, although different types an...
Riley CB, Archer FJ, Bailey JV.To compare the effects of different commercial nutrient media and sera on protein synthesis and maintenance of cellular density in cultures of the equine superficial digital flexor tendon (SDFT). Methods: 8 healthy 2- to 4-year-old horses. Methods: First Dulbecco's modified Eagle's medium, Ham's F12 nutrient mixture, RPMI 1640 medium, minimum essential medium with Earle's salts, minimum essential medium with Hanks' salts, and a Dulbecco's modified Eagle's medium/Ham's F12 nutrient mixture with 10% fetal bovine serum (FBS) were compared. Then FBS, fetal equine serum, and donor horse serum, each...
Valdez H, Clark RG, Hanselka DV.Flexible medical grade carbon fiber was surgically implanted in tenectomized or lacerated superficial and deep digital flexor tendons of 13 horses (7 clinical cases and 6 experimental), ranging in age from 15 months to 10 years and weighing 300 to 500 kg. The 6 experimental horses were euthanatized at 30-, 45-, 60-, and 90-day intervals for gross and histologic evaluation of the results. Three of the experimental horses served as their own controls. Of the 7 clinically affected horses, 3 were euthanatized because they developed laminitis or the wound failed to heal. The remaining 4 horses in t...
McIlwraith CW, Fessler JF.The usefulness of inferior check ligament desmotomy as a treatment for acquired tendon contracture in horses was evaluated in 13 cases of deep digital flexor (DDF) contracture and in 3 cases of combined superficial digital flexor (SDF) and DDF contracture. In 8 of 9 cases of DDF contracture in which the dorsal surface of the hoof had not passed beyond being vertical to the ground, the surgical procedure was successful in returning the limb to a normal position and function. Compared with DDF tenotomy, inferior check ligament desmotomy was a superior treatment technique because of decreased pos...
Dik KJ, van den Belt AJ, Keg PR.The diagnosis of restriction of free movement of the flexor tendons through the fetlock canal usually rests on the characteristic clinical appearance of this condition, or airtendography. In a series of seven normal Warmblood horses and 16 diseased horses of various breeds, the efficacy of ultrasonography in the diagnosis of this condition was determined. In normal limbs, the annular ligament is a very thin structure usually not visible on sonograms. In diseased limbs, ultrasonography outlined flexor tendon injury, distension and thickening of the digital sheath, peritendovaginal tissue prolif...
Alexander GR, Gibson KT, Day RE, Robertson ID.To measure the effects of transection of the accessory ligament of the superficial digital flexor (SDF) muscle (superior check desmotomy) on flexor tendon and suspensory ligament (SL) strain in vitro. Methods: In vitro experimental biomechanical investigation. ANIMALS USED: Ten equine cadaver forelimbs. Methods: The effects of superior check desmotomy were determined using equine cadaver forelimbs secured in a servocontrolled hydraulic testing machine. Strain sensors were used to measure strain on the superficial and deep digital flexor tendons and SL, and a goniometer was used to measure join...
Meagher DM, Aldrete AV.Lateral luxation of the superficial digital flexor tendon from the calcaneal tuber occurs in horses as a result of tearing or rupture of the medial retinaculum of the tendon. This report describes the repair of this condition in 2 Thoroughbred race horses, using a surgical technique in which 2 cancellous bone screws were placed in the calcaneus lateral to the tendon, along with suturing the medial retinaculum.
Barker WH, Wright IM.Accurate description of the calcaneal insertions of the superficial digital flexor tendon (SDFT) is lacking and inconsistent. The aim of this study was to undertake morphologic and morphometic evaluations of these structures to assist in elucidating their functional and pathogenic roles in displacement of the SDFT from the calcaneal tuber. Methods: Dissections were performed on 10 normal cadaveric hindlimbs. The anatomy was photographed to allow measurements at repeatable locations and differences in SDFT dimensions at the various locations were compared using a paired student t-test. Results:...
Horstmeier C, Ahrberg AB, Berner D, Burk J, Gittel C, Hillmann A, Offhaus J, Brehm W.The magic angle effect increases the MRI signal of healthy tendon tissue and could be used for more detailed evaluation of tendon structure. Furthermore, it could support the discrimination of hypointense artefacts induced by contrast agents such as superparamagnetic iron oxide used for cell tracking. However, magic angle MRI of the equine superficial digital flexor tendon has not been accomplished in vivo in standing low-field MRI so far. The aim of this in vivo study was to evaluate the practicability of this magic angle technique and its benefit for tracking superparamagnetic iron oxide-lab...
Wagner PC, Shires GM, Watrous BJ, Kaneps AJ, Schmotzer WB, Riebold TW.Fifteen horses with flexural deformity of the metacarpophalangeal joint were evaluated and their conditions were designated as mild, moderate, or severe. Evaluations were made on the basis of clinical signs and lesions seen on radiography. Horses with mild deformities were treated with corrective trimming and shoeing; those with moderate deformities were treated with desmotomy of the accessory ligament of the deep digital flexor tendon and corrective shoeing. Desmotomies of the accessory ligaments of both deep and superficial digital flexor tendons were performed on horses severely affected, f...
Gillis C, Sharkey N, Stover SM, Pool RR, Meagher DM, Willits N.Ultrasonographic cross sectional area (CSA) measurements of equine superficial digital flexor (SDF) tendon were obtained to determine the feasibility of ultrasonography for CSA measurement of tendon in vivo and in vitro. Ultrasonographic measurements were compared with a more traditional CSA measurement method, ink-blot analysis. In addition, values for ultrasonographic SDF tendon mean echogenicity were obtained in vivo and in vitro. The left forelimb SDF tendons of 23 horses were evaluated ultrasonographically. Cross sectional images were acquired at 4-cm intervals distal to the base of the a...
Hu AJ, Bramlage LR.To assess postoperative probability of racing, career longevity, and convalescent time in Thoroughbred racehorses with moderate to severe superficial digital flexor tendonitis (SDFT) in the forelimbs treated by desmotomy of the accessory ligament of the superficial digital flexor tendon (ie, superior check ligament desmotomy [SCLD]). Methods: Retrospective case series. Methods: 332 Thoroughbred racehorses with SDFT consecutively treated by means of SCLD. Methods: Medical records and racing records were reviewed to assess return to racing, number of races completed, time to first race, and life...
