Tarsal Sheath Research Articles

Disorders of the sustentaculum tali and the medial trochlear ridge of the talus in horses: Novel findings and surgical management of five cases

AbstractThe sustentaculum tali (ST) is located at the medial aspect of the tarsus and is considered a rare anatomic location for diseases. This retrospective case series describes the management of five horses with septic and non‐septic ST injuries. All horses were treated surgically with tenovaginoscopy, ST fragment and exostosis removal. In two cases, lameness was caused by an exostosis involving the ST and the plantar aspect of the medial trochlear ridge (MTR). There are no reports of exostosis involving ST and MTR causing lameness. In four horses, the long‐term outcome was considered good and the horses were able to return to the previous level; one horse developed a recurrence of ST and MTR exostosis leading to recurrence of lameness. Curettage of the ST and MTR exostosis, removal of fragments and tarsal sheath adhesions play a pivotal role in increasing prognosis and long‐term outcome. Poor prognosis is correlated with exostosis recurrence.

Ultrasound findings in tendons and ligaments of lame sport horses competing or training in South Florida venues during the winter seasons of 2007 through 2016

SummaryKnowledge of common soft tissue lesions in sport horses in training should prove beneficial for evaluating lameness and developing training and management regimens to avoid injury and aid rehabilitation. Medical records were reviewed from 2007 to 2016 to describe tendon/ligament lesions in lame sport horses training and competing at the same venues during the winter show circuit and identified by lameness and ultrasonographic examinations. Season, discipline, breed, age, gender, limb and ultrasound findings were recorded. Descriptive statistics were used to describe the population of horses. Significance of association of gender, discipline and limb with lesion type was evaluated using chi‐squared analyses. Values were considered significant at P ≤ 0.05. Lesions were identified in 296 horses: 176 dressage and 120 hunter/jumpers. Ninety‐two horses (31%) had multiple lesions. Suspensory ligament lesion locations (n = 281) were categorised as proximal (n = 144), body (n = 22) and branches (n = 115). Superficial digital flexor tendon (SDFT; n = 37), deep digital flexor tendon (DDFT; n = 27), inferior check ligament (ICL; n = 34), digital flexor tendon sheath (n = 17), distal sesamoidean ligament (n = 10), lower limb collateral ligament (n = 14), carpal sheath (n = 2), superior check ligament (n = 2) and tarsal sheath (n = 1) lesions were noted. Remaining lesions identified were medial branch SDFT (n = 2), lateral branch SDFT (n = 2), palmar annular ligament (n = 3), lateral plantar ligament (n = 2) and inter‐sesamoidean ligament (n = 1). Rear limb proximal suspensory abnormalities, specifically the right hindlimb (n = 68), were significantly over‐represented (P = 0.03). Suspensory origin, suspensory branch, ICL, SDFT and DDFT accounted for 82% of the abnormal findings identified. SDFT, DDFT and ICL lesions were most often identified in the front limb. The lesion type and location may provide insight in assessing training regimens, patient monitoring and rehabilitation guidelines.

Diffusion of Radiodense Contrast Medium Following Perineural Injection of the Deep Branch of the Lateral Plantar Nerve Using Two Different Techniques in Horses: an In Vivo Study.

This article evaluates and compares the diffusion pattern of radiopaque contrast medium following perineural analgesia of the deep branch of the lateral plantar nerve performed using two different techniques: weight-bearing or flexed. This was an in vivo experimental study. Eight horses were enrolled. Perineural injection of the right and left deep branch lateral plantar nerves was performed with a weight-bearing or flexed technique, using radiopaque contrast medium (iohexol). Radiographic evaluation was performed after 5 (T5), 15 (T15) and 30 (T30) minutes. The diffusion of contrast medium was assessed independently by two blinded readers who analysed the extension of the main contrast medium bulk and the maximum diffusion of contrast medium in both proximal and distal directions. The effect of time and technique employed on contrast medium diffusion was assessed using two-way analysis of variance for repeated measures (p ≤ 0.05). There was no significant difference in the diffusion of the contrast medium between the two techniques at T15. However, at T30 the weight-bearing technique resulted in a significantly increased diffusion in the proximal direction (p = 0.02). In one case, belonging to the weight-bearing group, contrast medium was identified within the tarsal sheath. There was no evidence of contrast medium in the tarsometatarsal joint of any horse, regardless of the technique used. The two techniques resulted in a similar diffusion at T15. However, the use of a weight-bearing technique resulted in a significant increase in proximal contrast medium diffusion 30 minutes after injection.

Case of focal dystrophic calcification in the peritarsal soft tissues of a horse

A 12-year-old Irish sports horse gelding presented with a recently developed oval firm mass at the plantaromedial aspect of right tarsus, located between the gastrocnemius and deep digital flexor tendon....

Tenoscopic‐assisted treatment of a solitary caudodistal tibial osteochondroma

SummarySolitary 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.

In vivodiffusion characteristics following perineural injection of the deep branch of the lateral plantar nerve with mepivacaine or iohexol in horses

Hindlimb proximal suspensory desmopathy is a common injury of sport horses but diagnosis can be difficult because diagnostic analgesia of the region lacks specificity. Perineural analgesia of the deep branch of the lateral plantar nerve (DBLPN) has been proposed as a more specific method of isolating pain of the proximal aspect of the suspensory ligament but the technique has not been evaluated in vivo. To determine the extent of diffusion of contrast medium and mepivacaine following DBLPN analgesia using a single-needle injection technique and to determine if there is inadvertent involvement of the tarsal sheath and/or tarsometatarsal (TMT) joint using this technique. In vivo experimental study. Perineural injection of the DBLPN was performed in 16 limbs with 3 ml of either mepivacaine hydrochloride or positive contrast medium. Contrast medium-injected limbs were radiographed 5, 15, and 30 min post injection and diffusion characteristics were described. In mepivacaine-injected limbs, synovial fluid from the TMT joint was obtained 10 and 20 min post injection and mepivacaine concentrations were analysed. At 5, 15 and 30 min post injection, the contrast medium extended, on average, 19.6, 20.6 and 21.0 mm proximal and 38.0, 43.5 and 51.9 mm distal to the injection site, respectively. Three of 8 (37.5%) limbs had evidence of contrast medium in the tarsal sheath. Two of 8 (25%) limbs had mepivacaine concentrations within the TMT joint sufficient to produce analgesia (>300 mg/l) at 10 min post injection. Contrast medium diffused further in a distal direction than in a proximal direction. Analgesia of the DBLPN can result in inadvertent involvement of the tarsal sheath and/or TMT joint.

Clinical and diagnostic imaging characteristics of lateral digital flexor tendinitis within the tarsal sheath in four horses.

Lateral digital flexor tendonitis is a rarely reported cause of hind limb lameness in performance horses. The purpose of this retrospective study was to describe clinical and diagnostic imaging findings for a group of horses with lateral digital flexor tendinitis within the tarsal sheath. Equine cases with a diagnosis of lateral digital flexor tendonitis and magnetic resonance imaging (MRI) studies of the affected region were retrieved from North Carolina University’s medical record database. Recorded data for included horses were signalment; findings from history, physical examination, lameness examination, and all diagnostic imaging studies; treatment administered; and outcome. Four horses met inclusion criteria. Lameness was mild/moderate in severity and insidious in onset in all patients. Responses to flexion tests were variable. All horses showed positive improvement(70–90%) in lameness after tarsal sheath analgesia. Radiographic, scintigraphic, and ultrasonographic findings were inconclusive. For all horses, MRI characteristics included increased T2, PD, and STIR signal intensity within the lateral digital flexor tendon in the area of the tarsal sheath. Tarsal sheath effusion was slight in three horses, and mild/moderate in one horse. With medical treatment, two horses were sound at 6-month follow up, one horse was sound at 1-year followup, and one horse had a slight persistent lameness (grade 1/5) at 9-month followup. Findings supported the use of MRI for diagnosing lateral digital flexor tendonitis within the tarsal sheath in horses. Affected horses may have a good prognosis for return to athletic performance following appropriate medical treatment.

Disease of the tarsal sheath in 13 horses

Disease of the tarsal sheath in 13 horses

Minimally invasive repair of a calcaneus fracture in a Standardbred foal

A 4-month-old Standardbred colt was examined because of a fractured right calcaneus of 8 days' duration with increased distraction of the fracture fragment evident on sequential radiographs. The foal was severely lame with diffuse periarticular tarsal swelling. Radiographically, a complete, displaced long oblique fracture of the right calcaneal body was evident. Because the fracture gap was increasing with time and lameness remained severe, despite medical management, surgical repair was recommended. The foal was anesthetized, and minimally invasive fracture reduction and internal fixation were achieved by use of two 4.5-mm cortical screws placed in lag fashion via stab incisions over the lateral aspect of the calcaneus. External coaptation with a Robert-Jones bandage only was used after surgery. The foal recovered well and the fracture healed appropriately, but at 8 weeks following surgery, tenosynovitis of the tarsal sheath had developed. This was attributed to the tip of the distal screw encroaching on the sheath. The screw was removed under anesthesia and the tarsal sheath drained. The tenosynovitis resolved with rest and bandaging. Fourteen months after surgery, the colt was free of lameness. Findings suggested that a minimally invasive internal fixation technique for treatment of a calcaneus fracture in horses may be successful and may be associated with decreased morbidity, compared with the use of open reduction and plate fixation.

Synoviocoeles associated with the tarsal sheath: Description of the lesion and treatment in 15 horses

To describe the presentation, clinical, ultrasonographic and endoscopic features associated with a defect in the tarsal sheath wall, to define the cavity created and to describe a method of treatment. So called 'false thoroughpins' can be caused by defects in the tarsal sheath wall creating a one way valve effect, removal of which could be therapeutic. Case records and diagnostic images of horses with synoviocoeles associated with the tarsal sheath were reviewed retrospectively and follow-up information obtained. Synoviocoeles were diagnosed in 15 horses. All were managed similarly and 10 horses had clinical resolution and returned to work. Terminology previously used to describe lesions involving the tarsal sheath does not define accurately the condition described and the term synoviocoele is recommended. Endoscopic enlargement of the sheath wall defect produced good clinical results in 10/15 horses. Clinicians should include synoviocoele in the list of differential diagnoses of fluid filled cavities associated with the tarsal sheath and should consider endoscopic surgery as a treatment modality.

In Vitro Evaluation of a Single Injection Technique for Diagnostic Analgesia of the Proximal Suspensory Ligament of the Equine Pelvic Limb

To examine the anatomic relationship of the deep branch of the lateral plantar nerve (DBLPN) with structures of the proximal metatarsal region, and to define the anatomic location of a solution injected using a single injection technique for diagnostic analgesia of the proximal suspensory ligament (PSL). Descriptive study. Cadaveric equine pelvic limbs (n=29). The proximal metatarsal region of both pelvic limbs (n=5 horses, 10 limbs) was dissected and measurements were made of anatomic structures relative to the head of the 4th metatarsal bone (HMT4). A single injection technique was used to inject dye 15 mm distal to the HMT4, axial to the MT4 at a depth of 25 mm in each limb from 10 equine cadavers (19 limbs). Hindlimbs were dissected and the position of the dye was recorded. DBLPN branched from the lateral plantar nerve (LPN) at a mean distance of 30 mm proximal to the HMT4 and entered the PSL at a mean distance of 17 mm distal to the HMT4. A 2nd DBLPN was observed in 1 of 10 dissected limbs. Blue dye surrounded the DBLPN in 18 limbs (95%). A single injection technique was likely to have resulted in desensitization of the DBLPN in 18 of 19 limbs (95%). This technique provides a reliable method using a single needle puncture for perineural analgesia of the DBLPN for diagnosis of proximal suspensory desmitis of the pelvic limb with a minimal risk of inadvertently desensitizing structures within the tarsal sheath and the tarsometatarsal joint.

Septic tenosynovitis of the tarsal sheath of an Arab gelding and suspected sepsis of the lateral digital flexor tendon subsequent to bacterial peritonitis

A 21-year-old Arab gelding with clinical signs of acute peritonitis had a perforating ulcer on the mesenteric border of the jejunum which resulted in localised contamination of the abdomen with...

Ultrasonographic Evaluation of the Metacarpus, Metatarsus, and Pastern

Ultrasonographic evaluation of the metacarpus (MC), metatarsus (MT), and pastern has been used to diagnose soft tissue injuries of these regions for the past two decades. Advancements in technology continue to improve user friendliness as well as our ability to diagnose tendon and ligament injuries. Relevance of these advances to the equine practitioner will be presented. Techniques to evaluate all major anatomic structures will be discussed, including the superficial and deep digital flexor tendons, inferior check ligament, suspensory ligament, straight and oblique distal sesamoidean ligaments, and collateral and abaxial and axial palmar/plantar ligaments of the pastern joint. Evaluation of associated synovial structures will be presented, including the carpal sheath, tarsal sheath, and digital sheath. An emphasis will be placed on measuring cross-sectional areas as a means to differentiate injured from noninjured structures and how to utilize those measurements to evaluate healing. Common history, physical examination findings, ultrasonographic features, healing, and prognosis for soft tissue injuries of MC, MT, and pastern will be reviewed. Practice tips to improve sonographic technique and image acquisition will also be presented.

Osteomyelitis of the sustentaculum tali in horses: 10 cases (1992-1998).

To determine outcome of horses with osteomyelitis of the sustentaculum tali (ST), with or without associated tarsal sheath tenosynovitis, following surgical debridement and lavage. Retrospective study. 10 horses in which a diagnosis of osteomyelitis of the ST had been made on the basis of history, physical examination findings, and results of radiography. Information on results of diagnostic testing, surgical findings, postoperative treatment, and short-term outcome was obtained from the medical records. Long-term follow-up information was obtained through reevaluation of horses at the teaching hospital and telephone conversations with referring veterinarians, owners, and trainers. Treatment consisted of surgical debridement, intra- and postoperative lavage, and long-term antimicrobial and anti-inflammatory treatment. Eight horses had evidence of involvement of the tarsal sheath. One horse was euthanatized after surgery because of a lack of response to treatment; the other 9 were discharged from the hospital. Severity of lameness had improved, but all still had grade-1 or -2 lameness at the time of discharge. One horse was euthanatized after discharge because of contralateral hind limb laminitis, and another horse was lost to follow-up. Of the remaining 7 horses, 6 returned to their previous use, and 1 was sound but retired for breeding for unrelated reasons. Results suggest that horses with osteomyelitis of the ST, with or without concomitant tarsal sheath tenosynovitis, can have an excellent to good outcome and may return to their previous use after surgical debridement of affected tissues and lavage of the tarsal sheath.

An investigation of injection techniques for local analgesia of the equine distal tarsus and proximal metatarsus

A positive radiographic contrast agent was injected into the tarsometatarsal (TMT) joints of both hindlimbs of 10 horses. Lateromedial radiographic views were obtained at 5, 15 and 30 mins after injection. Injection was successful in 19 of 20 limbs. Communication between the centrodistal (CD) and TMT joints was identified in 7 limbs (35%). Contrast agent extended around the tendons of tibialis cranialis (TC) and fibularis tertius (FT) in 18 limbs, and in 7 limbs some contrast entered the tarsal sheath. Slight to moderate plantar and/or distal extension of contrast agent was identified in 13 limbs. On a subsequent occasion positive contrast agent was injected subtarsally using one of two techniques and radiography was repeated. Contrast agent was principally distributed on the plantar aspect of the 3rd metatarsal bone, the plantar aspect of the suspensory ligament and between the superficial and deep digital flexor tendons. Extension of contrast agent into the TMT joint was identified in only 1 limb but in 8 limbs contrast agent extended into the tarsal sheath. The practical implications of these results include the possibility that local anaesthetic solution injected into the TMT joint may alleviate pain from the CD joint, the insertions of TC and FT or the tarsal sheath. It may also result in perineural analgesia of the dorsal metatarsal nerves or the plantar metatarsal nerves. In some cases subtarsal injection of local anaesthetic solution may result in alleviation of pain from the tarsal sheath. False negative results for subtarsal analgesia may be achieved by inadvertent injection into the tarsal sheath or into a blood or lymphatic vessel.

Surgical treatment of tarsal sheath effusion associated with an exostosis on the calcaneus of a horse

Surgical treatment of tarsal sheath effusion associated with an exostosis on the calcaneus of a horse

Unilateral distension of the tarsal sheath in the horse: a report of 11 cases.

Eleven horses with unilateral distension of the sheath are reported with emphasis on the use of plain and contrast radiography in diagnosis. Six had associated bony abnormalities of the sustentaculum tali, and two of these showed destructive or mixed destructive and proliferative lesions resulting from osteomyelitis. One horse had a fracture of the sustentaculum. In three horses proliferative changes were found. Bony changes were best demonstrated on a dorsomedial-plantarolateral oblique view. Contrast radiography of the tarsal sheath was performed in five cases without, and two horses with, associated bony lesions. In five cases ballooning with or without folding of the proximal aspect of the sheath was demonstrated. Additional band-like filling defects (two cases), triangular filling defect (one case), nodular intra-tendovaginal masses (two cases), or an extra-tendovaginal mass (one case) were noticed. The remaining two horses showed a semicircular collar shape dilation of the proximal aspect of the sheath. Contrast radiography appeared to be a helpful tool for the examination of tarsal sheath lesions. Two horses with associated bony changes were destroyed immediately after diagnosis, one failed to recover following surgical intervention and in three horses the outcome was unsatisfactory after conservative treatment. Three horses without associated bony lesions recovered completely after conservative treatment. One was operated on subsequently; the results are promising but the outcome of this case is not yet known. One was sold shortly after diagnosis and lost to follow up.

Use of contrast radiography in the investigation of tenosynovitis and bursitis in horses.

Contrast radiography, using a 25 per cent solution of sodium diatrizoate, has been used for the investigation of tenosynovitis and bursitis in horses. The procedure was undertaken on a series of 32 clinical cases and on specimens obtained at autopsy. Lesions affecting the extensor tendon sheaths at the carpus, the digital sheath, the tarsal sheath and the bursae at the elbow, hock and fetlock were examined by this means. The results showed the procedure offered the clinician useful information about the nature of the interior of these structures, particularly as regards the presence of adhesions and anastomoses between adjacent sheaths and joint capsules. Together with other clinical and laboratory findings, contrast radiography can assist in assessing the prognosis and in formulating appropriate treatment.