Histopathologic alterations in the eyelid after Hughes tarsoconjunctival flap: loss of Meibomian glands with preservation of accessory lacrimal glands

A 71-year-old female with invasive squamous cell carcinoma of the lower eyelid involving the ocular surface underwent surgical excision with negative margins and a subsequent reconstruction. The posterior lamellar defect was reconstructed with a Hughes tarsoconjunctival flap, and the anterior lamellar defect was reconstructed by advancing the lower eyelid skin. Three years later, the patient presented with signs suspicious for recurrence involving the tarsoconjunctival graft: a nodule along the mucocutaneus junction, symblepharon, and forniceal shortening. Repeat scouting biopsies showed variable degrees of moderate to severe squamous dysplasia so the patient underwent a staged full thickness excision of the lower eyelid and involved conjunctiva followed by reconstruction. Direct immunofluorescence was not diagnostic for ocular cicatrcial pemphigoid. Permanent histopathologic sections did not show any carcinoma, but the full thickness excisions involving the prior Hughes tarsoconjunctival flap highlighted two notable alterations: the Meibomian glands were absent and the accessory lacrimal glands of Wolfring were transposed to the mucocutaneous junction of the reconstructed lower eyelid.

Characteristics, surgical treatment, and outcomes of injuries involving the tarsus in greyhounds

Objective

The first objective of this study was to describe the type of tarsal injuries sustained, surgery performed, and postoperative complications in greyhounds presenting to a single veterinary hospital. An additional objective of the study was to determine the surgical site infection (SSI) and explantation rate, and if any variables were associated with an increased risk of SSI and/or explantation.

Animals

116 greyhounds receiving surgical intervention for a tarsal injury.

Proceures

Medical records from a single veterinary referral hospital were reviewed retrospectively. Data retrieved included signalment, details regarding the injury, surgical intervention, concurrent castration, surgical/anesthesia times, postoperative management, time to healing, and postoperative complications. In cases that underwent explantation, cause, time from initial surgery, and risk factors were evaluated.

Results

The most frequently diagnosed tarsal injuries were fracture of the central tarsal bone (CTB; 57.8%), calcaneal fracture (56.9%) and proximal intertarsal subluxation (34.5%). The most common injury combination was a CTB fracture with a calcaneal fracture (31.9%). In total 115 (99.1%) survived to discharge. Of these, 46 (40.0%) were diagnosed with an SSI and 59 (51.3%) underwent explantation. The most common indication for explantation was SSI. Concurrent medial and lateral surgical approaches was found to be associated with an increased likelihood of SSI and explantation.

Clinical relevance

Practitioners performing surgical intervention for tarsal injuries in greyhounds should be aware of the high SSI rate and likelihood that explantation will be required. This risk is elevated for injuries requiring a bilateral surgical approach.

Review of the Idaeaproximaria complex (Lepidoptera, Geometridae, Sterrhinae) with descriptions of four new species

The Idaeaproximaria complex is reviewed and four new species are described from China: Idaearectangularis Cheng & Han, sp. nov. from Guangxi and Fujian provinces, Idaearectispina Cheng & Han, sp. nov. from Hunan province, Idaeasetosa Xue & Han, sp. nov. from Hainan province, and Idaealinearis Xue & Han, sp. nov. from Hubei and Shaanxi provinces. Illustrations of adults and genitalia of the new species and known species are presented, and the variations in the form of the aedeagus of Idaeaproximaria are discussed.

Radiographic changes of the proximal third metatarsal bone do not predict presence or severity of proximal suspensory desmopathy in a predominately Quarter Horse population

BACKGROUND

Comparison of radiography to magnetic resonance imaging (MRI) can help objectively assess the value and limitations of radiographs in orthopaedic disease processes. The tarsus and proximal suspensory origin of the metatarsus are commonly imaged regions for lameness. The knowledge gained by comparison between imaging modalities will aid in improving accuracy of radiographic interpretation.

OBJECTIVE

To compare the radiographic and MRI findings of the proximal third metatarsal bone (MTIII) and proximal suspensory ligament using MRI as the gold standard.

STUDY DESIGN

Retrospective observational study.

METHODS

Single hindlimbs of 35 horses with radiographic and high-field (3Tesla (3T)) MRI studies were blindly evaluated by two board-certified veterinary radiologists and a radiology resident. Severity and location of the following parameters were assessed: radiographic MTIII sclerosis and lucent regions, MRI endosteal metatarsal sclerosis and bone marrow lesions, plantar cortical proliferation and resorption, and proximal suspensory desmopathy (PSD).

RESULTS

Radiographic osseous changes of MTIII were identified in 54% of limbs, whereas 40% limbs had osseous changes on MRI: 43% of limbs had PSD on MRI. No significant association was found between the presence of radiographic changes in MTIII and PSD on MRI (P = .7). A statistically significant association and positive correlation was found between the severity of radiographic changes and MTIII plantar cortical proliferation and resorption on MRI (P = .01).

MAIN LIMITATIONS

Retrospective study with no histopathology. Ability to correlate findings with lameness was limited by the lack of standardised time intervals between onset of lameness, diagnostic analgesia and advanced imaging.

CONCLUSION

Radiographic bony changes of proximal MTIII do not reliably predict presence or severity of PSD but are associated with osseous changes at the proximal MTIII. The presence of radiographic changes should warrant additional diagnostics in the region prior to making conclusions about the presence or absence of PSD.

What Is the Best Candidate to Replace the Tarsus? A Biomechanical, Histological, and Optical Study Comparing Five Grafts

Purpose

Reconstruction of the posterior lamella after eyelid tumor removal is challenging and not consensual. Tarsus is the most suitable graft, but is only available in small amounts. Herein, we aim to determine the most appropriate way to replace the tarsus by comparing the biomechanical, histological, and optical properties of five commonly used grafts.

Methods

This study was conducted at the University hospital of Nice between June 2019 and June 2020. Five posterior lamella grafts (tarsus, conchal cartilage, sclera, hard palate, and dermis) were harvested in five fresh frozen cadavers. Biomechanical properties were assessed by tractometry. Collagen and elastin fibers were analyzed by using histological analysis and optical characterization with the second harmonic generation imaging.

Results

The mean Young's modulus was 8.92 MPa (range, 2.90-22.90 MPa), 1.05 MPa (range, 0.39-1.76 MPa), 8.72 MPa (range, 2.0-23.50 MPa), 2.57 MPa (range, 0.41-4.35 MPa), and 1.44 MPa (range, 0.71-2.30 MPa) for the tarsus, the conchal cartilage, the sclera, the hard palate mucosa, and the dermis, respectively. The mean tensile strength was 3 MPa (range, 1.70-6.88 MPa), 0.54 MPa (range, 0.13-0.79 MPa), 2.87 MPa (range, 1.23-5.40 MPa), 1.4 MPa (range, 0.21-2.40 MPa) and 1.0 MPa (range, 0.46-1.43 MPa) for the tarsus, the conchal cartilage, the sclera, the hard palate mucosa, and the dermis, respectively. Hard palate mucosa was the closest to the tarsus regarding the ratio of elastin and collagen fibers. The average second harmonic generation intensity was 221 arbitrary units (a.u.) (range, 165-362 a.u.), 182 a.u. (range, 35-259 a.u.), 369 a.u. (range, 206-533 a.u.), 108 a.u. (range, 34-208 a.u.), and 244 a.u. (range, 195-388 a.u.) for the tarsus, the conchal cartilage, the sclera, the hard palate mucosa, and the dermis, respectively. The hard palate mucosa and the dermis were the closest to the tarsus regarding the collagen fiber size and orientation, respectively.

Conclusions

By attributing 2 points for each characteristic (biomechanical, histological, and optical), the hard palate mucosa and the sclera seem to be the most suitable grafts to replace the tarsus.

Translational Relevance

The aim of this article was to assess the biomechanical, histological and optical characteristics of five of the most commonly used tarsal grafts; this may be helpful in decisions for clinical practice.

A pilot study: Can calcaneus radiographic image be used to determine sex and breed in cats?

This study examined whether radiographic images measurements of the calcaneus in cats are determinative of sex and breed. For this purpose, radiographic images of 70 cats (37 male and 33 females) of different ages (from one to 18 years) and different breeds (41 mix-breed, 18 Scottish Fold and 11 British Shorthair cats) without orthopaedic problems were used. Right tarsal joint radiographs of these orthopaedically healthy cats were taken. Four linear measurements and two angle values of the calcaneus were obtained from the radiographic images. The MANOVA result showed that the most determining factor between the three groups was the greatest width (p value = 0.001). Calcaneal body length, calcaneal greatest length and calcaneal shortest depth were higher in mix-breed cats. Calcaneal tuber length was higher in Scottish Fold cats. The only statistically significant difference between Scottish Fold and British Shorthair was in the calcaneal tuber length (p value = 0.04). In the comparison made between the sexes regardless of species, the linear measurements in males were higher than in females. It was determined that these parameters are statistically significant in terms of sex differentiation in cats. Dorsal and plantar calcaneal angles are not sex determinants in cats. The effect of age on other measurements was analysed by correlation test. However, the effect of age on the measurements was not statistically significant. Mix-breed cats were examined in four groups according to their colour (grey, black-white, yellow, tri-colour). No statistically significant difference was found between calcaneal measurements of cats with different skin colour genotypes. In this study, calcaneus measurements were both determinative between breeds and sexes in cats.

A robotic leg inspired from an insect leg

While most insect-inspired robots come with a simple tarsus, such as a hemispherical foot tip, insect legs have complex tarsal structures and claws, which enable them to walk on complex terrain. Their sharp claws can smoothly attach and detach on plant surfaces by actuating a single muscle. Thus, installing an insect-inspired tarsus on legged robots would improve their locomotion on complex terrain. This paper shows that the tendon-driven ball-socket structure provides the tarsus with both flexibility and rigidity, which is necessary for the beetle to walk on a complex substrate such as a mesh surface. Disabling the tarsus' rigidity by removing the socket and elastic membrane of a tarsal joint, means that the claws could not attach to the mesh securely. Meanwhile, the beetle struggled to draw the claws out of the substrate when we turned the tarsus rigid by tubing. We then developed a cable-driven bio-inspired tarsus structure to validate the function of the tarsus as well as to show its potential application in the legged robot. With the tarsus, the robotic leg was able to attach and retract smoothly from the mesh substrate when performing a walking cycle.

Tarsus-Orbicularis-Septum Fixation in Double-Eyelid Blepharoplasty: A Reliable and Flexible Technique

Purpose

Incisional double eyelid blepharoplasty is the most common cosmetic operation in East Asia. Although numerous articles on surgical techniques have been published, complications, such as fold loss, asymmetry, and visible scars, still exist. To create a stable and dynamic double-eyelid crease, the author has introduced a modified technique of double-eyelid blepharoplasty.

Patients and Methods

The authors introduced a new surgical technique to reduce complications and create reliable and dynamic double eyelids. The orbicularis oculi muscle of the lower flap was anchored on the tarsus and sutured with the distal part of the septal flap. The skin incision was closed by skin–septal flap–skin suture. Postoperative evaluations were assessed at the twelfth postoperative month.

Results

One hundred ninety-three patients underwent double eyelidplasty with the TOS fixation technique. The mean follow-up duration was 18.6 months (range, 12–30 months). In the aesthetic outcome evaluation, 88 (45.6%) patients had very much improved results, 56 (29.0%) had much improved results, 29 (15.0%) had improved results, 8 (4.1%) had no change and 12 (6.2%) had worse results. Complications included crease asymmetry (n=7, 3.6%), partial fold loss (n=8, 4.1%) and complete fold loss (n =5, 2.6%).

Conclusion

Tarsus-orbicularis-septum (TOS) fixation is a reliable and flexible surgical technique for creating stable and dynamic double-eyelid creases.

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Periarticular plasma cell tumors in cats

This report describes periarticular plasma cell tumors with abundant amyloid in 11 cats. The tarsus was the most commonly affected joint (10/11), and the masses were often circumferential around the tarsal joint, involving the dermis and subcutis. The 2 cases in which synovium was examined had neoplastic cells expanding the synovium. Three of the 5 cases staged radiographically had bony lysis of the affected joint. Cutaneous biopsy specimens often consisted of more amyloid than plasma cells, making the diagnosis difficult on small samples. Follow-up information was available in 7 cases; in those cases, the median survival was 194 days (range 53-671 days). Four cases had confirmed metastases, most often to regional lymph nodes, liver, and spleen. Although canine cutaneous plasma cell tumors are typically benign, those with abundant amyloid surrounding the joints of cats may involve deeper tissues and have a more aggressive behavior. These tumors can be difficult to diagnose due to low cellularity and abundant amyloid.

Traumatic joint luxations in cats: Reduce, repair, replace, remove

PRACTICAL RELEVANCE

Traumatic joint luxations are usually associated with significant trauma and there may be concomitant systemic injury. Joints are unstable as a result of injury to one or more supporting structures and the clinician should aim to determine which structures are damaged with physical examination, diagnostic imaging and careful assessment under sedation/anaesthesia. The aim is to reduce the joint back to its anatomical position, and then to maintain this through repair of damaged structures. However, where this is not possible, replacement or removal (arthrodesis/excision arthroplasty) of the joint remain viable options.

CLINICAL CHALLENGES

Owing to the small size of feline joints and the severity of damage often seen, surgical management of these cases can be challenging. The first priority is to ensure the patient is systemically well before embarking on any specific surgical treatment of a luxated joint. Cats also present challenges in the postoperative period and a lack of patient and owner compliance can be detrimental to postoperative outcomes.

AIMS

This article aims to help the reader diagnose joint luxations and to assist decision-making with an overview of the management and treatment options available.

EVIDENCE BASE

There are a number of original articles and textbook chapters in the literature covering aspects of different joint luxations, particularly for the more common luxations. This article draws on information from key feline research and, where necessary, extrapolates from relevant canine research. The authors also offer practical guidance based on their own clinical experience.

Ultrasound-assisted injection of the centrodistal joint in the horse

BACKGROUND

Injection of the centrodistal (CD) joint in the horse is a commonly performed procedure for both diagnostic and therapeutic purposes. This procedure can be technically challenging, and while radiographic guidance has been previously used, ultrasound localised injection of the CD joint has not been described.

OBJECTIVES

The purpose of this study was to explore the feasibility of using ultrasound localisation to increase the accuracy of CD joint injection.

STUDY DESIGN

Experimental method assessment.

METHODS

One operator performed the ultrasound and injection of 24 CD joints in 12 sedated horses. The joints were injected with iohexol (2 ml), sterile saline (1.5 ml) and amikacin (0.5 ml). Dorsoplantar and dorsomedial plantarolateral radiographic projections were obtained immediately after injection to evaluate the presence of contrast material in the CD joint.

RESULTS

The CD joint was successfully injected in 17/24 joints, representing a 70.8% accuracy.

MAIN LIMITATIONS

The horses used in this study were from the University research herd, and not clinical cases. One investigator performed all the ultrasonography and CD joint injections.

CONCLUSIONS

The use of ultrasound localisation could improve success of CD joint injection as well as improve the learning curve of less experienced practitioners learning this procedure.

Distal leg structures of the Aculeata (Hymenoptera): A comparative evolutionary study of Sceliphron (Sphecidae) and Formica (Formicidae)

The distal parts of the legs of Sceliphron caementarium (Sphecidae) and Formica rufa (Formicidae) are documented and discussed with respect to phylogenetic and functional aspects. The prolegs of Hymenoptera offer an array of evolutionary novelties, mainly linked with two functional syndromes, walking efficiently on different substrates and cleaning the body surface. The protibial-probasitarsomeral cleaning device is almost always well-developed. A complex evolutionary innovation is a triple set of tarsal and pretarsal attachment devices, including tarsal plantulae, probasitarsomeral spatulate setae, and an arolium with an internal spring-like arcus, a dorsal manubrium, and a ventral planta. The probasitarsal adhesive sole and a complex arolium are almost always preserved, whereas the plantulae are often missing. Sceliphron has retained most hymenopteran ground plan features of the legs, and also Formica, even though the adhesive apparatus of Formicidae shows some modifications, likely linked to ground-oriented habits of most ants. Plantulae are always absent in extant ants, and the arolium is often reduced in size, and sometimes vestigial. The arolium contains resilin in both examined species. Additionally, resilin enriched regions are also present in the antenna cleaners of both species, although they differ in which of the involved structures is more flexible, the calcar in Sceliphron and the basitarsal comb in Formica. Functionally, the hymenopteran distal leg combines (a) interlocking mechanisms (claws, spine-like setae) and (b) adhesion mechanisms (plantulae, arolium). On rough substrate, claws and spine-like setae interlock with asperities and secure a firm grip, whereas the unfolding arolium generates adhesive contact on smooth surfaces. Differences of the folded arolium of Sceliphron and Formica probably correlate with differences in the mechanism of folding/unfolding.

MR and CT Imaging of the Normal Eyelid and its Application in Eyelid Tumors

T-staging of most eyelid malignancies includes the assessment of the integrity of the tarsal plate and orbital septum, which are not clinically accessible. Given the contribution of MRI in the characterization of orbital tumors and establishing their relations to nearby structures, we assessed its value in identifying different eyelid structures in 38 normal eyelids and evaluating tumor extension in three cases of eyelid tumors. As not all patients can receive an MRI, we evaluated those same structures on CT and compared both results. All eyelid structures were identified on MRI and CT, except for the conjunctiva on both techniques and for the tarsal muscles on CT. Histopathology confirmed the MRI findings of orbital septum invasion in one patient, and the MRI findings of intact tarsus and orbital septum in another patient. Histopathology could not confirm or exclude tarsal invasion seen on MRI on two patients. Although imaging the eyelid is challenging, the identification of most eyelid structures is possible with MRI and, to a lesser extent, with CT and can, therefore, have an important contribution to the T-staging of eyelid tumors, which may improve treatment planning and outcome.

Description of a rare osteochondrosis lesion of the medial aspect of the distal intermediate ridge of the tibia in seven Thoroughbred horses (2008-2018)

Osteochondritis dissecans (OCD) of the distal intermediate ridge of the tibia (DIRT) is commonly identified on either the lateral to medial (LM) or dorso45°medial-plantarolateral oblique (D45M-PLO) projection of the tarsus. This manuscript describes a retrospective case series out of Hagyard Equine Medical Institute, for which medical records and radiographic projections of the tarsus were reviewed, consistent with Keeneland's repository requirements. This original investigation identified seven yearling Thoroughbred horses between 2008 and 2018 with radiographic signs of atypical osteochondrosis lesions within the tarsus. The atypical lesions, originating along the medial margin of the distal intermediate ridge of the tibia, were initially only diagnosed on the dorso10°lateral-plantaromedial (D10L-PMO) projection and were overlooked on the LM and D45M-PLO views. Following the diagnosis of osteochondrosis in these seven cases, the radiographs were reviewed and re-evaluated, but osteochondrosis and/or fragmentation could not be definitively diagnosed on the LM and/or D45M-PLO projections alone. Our findings highlight the importance of a complete radiographic study of the equine tarsus when screening horses for OCD lesions of the distal intermediate ridge of the tibia and that atypical DIRT lesions may go undetected if the D10L-PMO projection is not performed.

Biomechanical and Morphologic Effects of Collagen Cross-Linking in Human Tarsus

Purpose

To investigate the feasibility of increasing the stiffness of human tarsal tissue following treatment with riboflavin and ultraviolet A (UVA) to induce cross-linking of collagen fibers.

Methods

In this case control study, 18 right and left upper eyelids were excised en bloc from 18 fresh-frozen cadavers. One side served as the control while the samples from the opposite side were cross-linked. Four 2 × 6-mm vertical strips of central tarsus were cut from the superior to inferior border of each tarsal plate. Sample tissue was irradiated with UVA at 6 mW/cm² for 18 minutes. A microtensile load cell and an optical coherence tomography scanner allowed calculation of stiffness (Young's modulus). Six cross-linked samples and corresponding controls were stained with hematoxylin and eosin (H&E) and Masson trichrome stains. Four controls and four cross-linked samples were also reviewed with a transmission electron microscope.

Results

Mean Young's modulus in the linear region for controls was 28 ± 9 MPa and was much higher at 138 ± 8 MPa for cross-linked samples (P < 0.001), yielding a 493% mean stiffness increase. Staining with H&E and Masson did not reveal any histologic changes. Transmission electron microscopy showed a decrease in average diameter of 50 randomly selected collagen fibers from 47.2 ± 1.9 nm prior to cross-linking to 34.2 ± 1.1 nm post cross-linking (P < 0.001). Qualitatively, the collagen fibers appeared more closely packed following cross-linking.

Conclusions

The findings of this study suggest that collagen cross-linking is a viable and effective modality for increasing the stiffness of human tarsal plates.

Translational Relevance

This work provides proof that collagen cross-linking produces stiffening of the human tarsal plate and may be used in disorders that cause eyelid laxity.

The association between collagen and bone biomarkers and radiographic osteoarthritis in the distal tarsal joints of horses

BACKGROUND

Osteoarthritis (OA) of the distal intertarsal (DIT) and tarsometatarsal (TMT) joints occurs commonly. Synovial fluid (SF) biomarkers of collagen and bone turnover have potential clinical value.

OBJECTIVES

To measure SF biomarker concentrations from DIT and TMT joints in adult horses and determine if they correlate with radiographic OA severity and are higher in joints with radiographic OA compared to controls.

STUDY DESIGN

Cross-sectional.

METHODS

Radiographic OA of DIT and TMT joints was evaluated from adult horses (5-35 years old). Overall radiographic scores divided horses into those with mild or moderate radiographic OA (16 joints from 9 horses) or controls (13 joints from 9 horses). Direct biomarkers of OA (Carboxypropeptide of type II collagen = CPII, carboxy-neoepitope of type II collagen exposed after collagenase-cleavage = C2C, Bone alkaline phosphatase = BAP and Chondroitin sulfate epitope = CS846) were measured via ELISA and CPII/C2C was calculated. Biomarkers were correlated with radiographic findings and concentrations from those with radiographic OA to control joints and were compared.

RESULTS

Concentrations of CPII (R = 0.84, P<0.001), C2C (R = 0.69, P<0.001) and BAP (R = 0.41, P = 0.03) as well as CPII/C2C (R = 0.69, P<0.001) values positively correlated with overall radiographic scores. Adjusted means ± s.d., after controlling for age, for CPII (P<0.001), C2C (P<0.001), CPII/C2C (P = 0.004) and BAP (P = 0.05) were significantly higher in DIT and TMT joints with radiographic OA (CPII: 2174.45 ± 1064.01; C2C: 233.52 ± 51.187; CPII/C2C: 9.01 ± 4.09; BAP: 21.98 ± 15.34) compared to controls (CPII: 594.53 ± 463.05; C2C: 153.12 ± 48.95; CPII/C2C: 3.96 ± 2.38; BAP: 12.76 ± 3.61). CPII (P<0.001), C2C (P = 0.001) and CPII/C2C (P = 0.001) were significantly higher with moderate radiographic OA (CPII: 2444.61 ± 772.78; C2C: 248.90 ± 44.94; CPII/C2C: 9.47 ± 2.97) compared to controls (CPII: 658.38 ± 417.36; C2C: 156.49 ± 47.61; CPII/C2C: 4.15 ± 2.04), with CPII also showing significantly higher concentrations (P = 0.04) with mild radiographic OA compared (1515.00 ± 584.95) to controls (658.38 ± 417.36). There were no differences in CS846 concentrations between radiographic OA and control joints. Age positively correlated with CPII (R = 0.48, P = 0.01) and C2C (R = 0.44, P = 0.02) concentrations.

MAIN LIMITATIONS

Radiographic OA was assessed, not clinical lameness. Controls were not age-matched to those with spontaneous radiographic OA.

CONCLUSIONS

There is an association between collagen (CPII, C2C and CPII/C2C) and bone (BAP) biomarkers and radiographic OA in the distal tarsal joints of horses.

Palpebral Tarsal Solitary Neurofibroma

Solitary neurofibroma is a rare, benign tumor of the peripheral nerve sheath, and is often associated with neurofibromatosis type 1. Herein, a case of palpebral tarsal solitary neurofibroma in a patient without neurofibromatosis is presented, with a review of the literature. A 68-year-old man presented with a subcutaneous mass in the right upper eyelid of 6 months’ duration. Eversion of the eyelid revealed a round, reddish mass on the lateral part of the tarsal plate which measured 12x8 mm in size. The lesion was excised with its tarsal base, diagnosed histologically, and did not recur during a follow-up of 34 months. Isolated, solitary neurofibroma of the eyelid has been reported in a total of 7 cases, including the case presented herein. The tumors arose from the eyelid margin in 4 cases, from the tarsal plate in 2 cases, and from the supratarsal conjunctiva in 1 case. The tumor did not recur after surgical excision in 5 cases for which follow-up data were available.

What are the most accurate categories for mammal tarsus arrangement? A review with attention to South American Notoungulata and Litopterna

The arrangement of the tarsus has been used to differentiate afrotherian and laurasiatherian ungulates for more than a century, and it is often present in morphological matrices that include appendicular features. Traditionally, it has two states: (i) an alternating tarsus, where proximal elements are interlocked with central and distal elements positioned like the bricks of a wall; and (ii) a serial tarsus, where elements are not interlocked. Over the years, these states became synonymous with the presence or absence of an astragalocuboid contact. Within the South American order Notoungulata, a third disposition was recognized: the reversed alternating tarsus, associated with a calcaneonavicular contact. This state was considered to be a synapomorphy of 'advanced' Toxodontia families (Notohippidae, Leontiniidae and Toxodontidae), but a further inspection of its distribution shows that it occurs throughout Mammalia. Additionally, it overlaps the serial tarsus condition as originally defined, and it probably has no functional or phylogenetic significance. Calcaneonavicular and astragalocuboid contacts are non-exclusive, and their presence within a species, genus or family is not constant. Serial and alternating imply movements of the articulations of the mid-tarsus in the transverse axis, while reverse alternating refers to a small calcaneonavicular contact that sometimes occurs in a serial condition or to a significant displacement of the tarsal articulations in a different (proximodistal) axis. The proximodistal arrangement of the joints could be functionally significant. Two new states are observed and defined: (i) 'flipped serial', present in Macropodidae, in which the calcaneocuboid articulation is medially displaced and significantly larger than the astragalonavicular contact, but the relationships between proximal and central elements are one to one; and (ii) 'distal cuboid', an extreme proximodistal displacement of the astragalonavicular joint. Serial and alternating, as originally defined (i.e. without any reference to which bone contacts which), seem to be the best states for classifying tarsal arrangement though as the disposition of distal or central bones in relationship to proximal bones.

Prevalence, radiographic resolution and outcomes of slab fractures of the third and central tarsal bones in juvenile Thoroughbred horses

BACKGROUND

Veterinarians are required to interpret the significance of radiographic findings for sale, soundness and future racing performance of weanling and yearling Thoroughbreds. We investigated the prevalence and radiographic appearance of slab fractures of the third (T3) and central tarsal (Tc) bones.

METHODS

Weanling and yearling horses with complete or incomplete T3 or Tc fracture were identified by searching a database of radiographs. The prevalence and radiographic appearance at initial diagnosis and after continued pasture turnout, as well as prognosis for racing, of fractures of T3 and Tc were determined.

RESULTS

Fractures were identified in 186 tarsi (184 T3 fracture only, 1 Tc fracture only, 1 Tc and T3 fracture) of 157 horses (126 unilateral T3, 29 bilateral T3, 1 contralateral Tc and T3, 1 unilateral Tc and T3) from 7676 examinations. The prevalence of T3 and Tc fractures was 2.40 (95% CI 2.07, 2.76) and 0.04 (95% CI 0.01, 0.11) per 100 radiographic examinations respectively. Fractures were identified on the D556-65°MPlLO view and occurred by survey examination at 11.1 ± 1.3 months in 85.7% horses. At initial diagnosis, 84.3% of T3 fractures appeared incomplete and involved the distal articular surface. Fracture score improved (P < 0.001), and dorsal modelling (P < 0.001) and osteoarthritis score increased in the distal intertarsal joint (P < 0.001), but not the tarsometatarsal joint, between survey and repository examinations. Fractures healed by repository examination in 71.9% of tarsi if there was > 6 months between examinations. There was no difference in sale price, and horses with T3 fractures had fewer trials when 2 and 3 years old (P = 0.023), yet no difference in other parameters of racing success when 2 or 3 years old compared with controls.

CONCLUSION

Tarsal slab fractures can occur in juvenile Thoroughbreds and most heal with continued pasture turnout of > 6 months. Further investigation is required to determine risk factors and before making firm conclusions regarding the optimal management, prognosis for racing and long-term soundness.

Comparing the clinical success rate of the dorsolateral approach to the medial approach for injection of the centrodistal joint in the horse

BACKGROUND

Centrodistal joint injection is an important component of lameness evaluation and treatment. Successful injection is poor for the medial approach. The dorsolateral approach is an alternative but has not been validated with contrast medium. Radiograph-guidance has not been studied to determine its necessity or benefit for either approach.

OBJECTIVES

To determine if the dorsolateral approach to the centrodistal joint is more successful than the medial approach. To determine if radiograph-guidance is beneficial.

STUDY DESIGN

Prospective, randomised study.

METHODS

Three operators injected 98 centrodistal joints in total, each horse served as its own control. In Phase 1, injections were performed by standard technique. In the Phase 2, operators were allowed to use radiography to assist needle placement. Contrast deposition was evaluated by a single radiologist.

RESULTS

Without radiographic assistance, 10/25 (40%) joints were successfully injected using either the medial or dorsolateral approach. With radiographic assistance, 19/24 (79%) joints were successfully injected using the medial approach, 11/24 (46%) joints were successfully injected using the dorsolateral approach.

MAIN LIMITATIONS

The population consisted of aged horses representing a variety of breeds with existing osteoarthritis, and multiple operators were recruited.

CONCLUSIONS

The dorsolateral approach was equivalent to the medial approach when traditional injection techniques were used. Radiograph-guidance improved success of the medial approach, but not the dorsolateral approach. Many injections performed from the dorsolateral approach (32/49; 65%) resulted in extensive perivascular subcutaneous contrast deposition after infiltration into the tarsal canal. Further research is needed to improve injection success of the centrodistal joint when using the dorsolateral approach.

An unusual case of idiopathic calcinosis of the eyelid

Idiopathic subepidermal calcinosis, also known as idiopathic calcinosis cutis, is a rare condition, which typically presents as a small, hard, subepithelial mass in the absence of systemic disease and trauma. We report on an atypical case of idiopathic calcinosis, which appeared in an otherwise healthy 61-year-old female along the tarsus of her right upper eyelid. The purpose of this case report is to demonstrate idiopathic calcinosis in an unusual location that is deep to the dermis and to discuss the vast differential diagnosis of this entity.

A comparison of tarsal morphology and traction force in the two burying beetles Nicrophorus nepalensis and Nicrophorus vespilloides (Coleoptera, Silphidae)

Our aim was to compare friction and traction forces between two burying beetle species of the genus Nicrophorus exhibiting different attachment abilities during climbing. Specifically, the interaction of adhesive hairs and claws during attachment with respect to various surface properties was investigated by using a 2 × 3 experimental design. Traction force was measured for two different surface energies (hydrophilic vs hydrophobic) varying in roughness from smooth to micro-rough to rough. Nanotribometric tests on single legs were also performed. The external morphology of the attachment devices investigated by scanning electron microscopy suggested higher intra-specific (intersexual) than inter-specific differences. Whereas differences between the two species in traction force were high on smooth surfaces, no differences could be detected between males and females within each species. With claws intact, both species showed the highest forces on rough surfaces, although N. nepalensis with clipped claws performed best on a smooth surface. However, N. nepalensis beetles outperformed N. vespilloides, which showed no differences between smooth and rough surfaces with clipped claws. Both species demonstrated poor traction forces on micro-rough surfaces. Results concerning the impact of surface polarity were inconclusive, whereas roughness more strongly affected the attachment performance in both species. Nanotribometric analyses of the fore tarsi performed on micro-rough and rough surfaces revealed higher friction in the proximal (pull) direction compared with the distal (push) direction. In these experiments, we detected neither differences in friction performance between the two species, nor clear trends concerning the influence of surface polarity. We conclude that the investigated morphological traits are not critical for the observed interspecific difference in attachment ability on smooth surfaces. Furthermore, interspecific differences in performance are only clear on smooth surfaces and vanish on micro-rough and rough surfaces. Our results suggest that even subtle differences in the adhesion-mediating secretion in closely related species might result in qualitative performance shifts.

Arthroscopic and Endoscopic Management of Posttraumatic Hindfoot Stiffness

Ankle, hindfoot, and toe stiffness can result from hindfoot trauma. It can be due to capsular fibrosis, tendon adhesion, muscle fibrosis, or malunion. For symptomatic stiffness that is resistant to nonoperative treatment, operative treatment should be considered. It is important to tackle the sources of stiffness, and careful preoperative clinical assessment is the key for proper formulation of the surgical plan. Whenever possible, arthroscopic/endoscopic surgery is preferable to open surgery because less extensive dissection and small surgical incisions allow immediate vigorous mobilization of the foot and ankle.

Zinc finger protein rotund deficiency affects development of the thoracic leg in Bombyx mori

The insect limb develops from the imaginal disc or larval leg during metamorphosis. The molecular mechanisms involved in the development from the larval to the adult leg are poorly understood. Herein, we cloned the full length of a zinc finger gene rotund from Bombyx mori (Bmrn), which contained a 1419 bp open reading frame, and encoded a 473 amino acid protein. Reverse transcription polymerase chain reaction and Western blot analyses demonstrated that Bmrn was expressed at higher levels in the epidermis than in other tissues tested, and it showed a very high expression level during metamorphosis. Knock-down of Bmrn produced defects in the tarsus and pretarsus, including the fusion and reduction of tarsomeres, and the developmental arrest of pretarsus. Our data showed that Bmrn is involved in the formation of the tarsus and pretarsus, whereas its homologous gene in Drosophila has been shown to affect three tarsal segments (t2-t4), suggesting that the remodeling of the leg has involved changes in the patterning of gene regulation during evolution.

Subdivision of the neotropical Prisopodinae Brunner von Wattenwyl, 1893 based on features of tarsal attachment pads (Insecta, Phasmatodea)

The euplantulae of species from all five genera of the Prisopodinae Brunner von Wattenwyl, 1893 were examined using scanning electron microscopy with the aim to reveal the significance of attachment pads regarding their phylogenetic relationships. The split into the conventional two sister groups is supported by the two-lobed structure of the euplantulae with a smooth surface in the Prisopodini and a nubby surface microstructure in the Paraprisopodini. The two lineages are well distinguishable by this feature, as well as by the shape of the euplantulae themselves. The functional importance of the attachment pad surface features is discussed.

FRACTURE OF THE CENTRAL TARSAL BONE IN NONRACEHORSES: FOUR CASES

Fractures of the central tarsal bone are a rarely recognized cause of acute severe hind limb lameness in nonracehorses. Diagnosis of these fractures can be challenging and little is known about their configuration or outcome. The objectives of this retrospective case series study were to describe the clinical features, imaging findings, and outcomes of fractures of the central tarsal bone in a sample of nonracehorses. Medical records from 2001 to 2014 were searched for cases of central tarsal bone fractures in nonracehorses. All available imaging findings including radiography, ultrasound, computed tomography (CT), and/or nuclear scintigraphy were reviewed. History, clinical presentation, and outcome were collected from the records. Four horses met the inclusion criteria. All had a similar configuration as a simple nondisplaced slab fracture in a dorsomedial to plantarolateral orientation. Initial radiographs failed to reveal the fracture in three of four cases. When additional plantarolateral-dorsomedial oblique radiographic views were obtained, the fracture could be identified in all cases. Fractures of the central tarsal bone seemed to occur in a consistent dorsomedial to plantarolateral orientation in this sample of nonracehorses, which is different from the configuration previously reported in racehorses. While CT can be used for detection and assessment of these fractures, authors propose that radiography can also identify these fractures with the appropriate view. Authors recommend the use of several plantarolateral to dorsomedial radiographic projections at varying degrees of obliquity for horses with a suspected central tarsal bone fracture.

Total Bilateral Tarsal Coalition: A Case Report

A 35-year-old male presented with pain and swelling of his right foot and ankle. His pain developed gradually and without overt pedal deformity. The radiologic examination revealed complete fusion of all tarsal bones of his right foot. Comparative radiographs of his left foot also showed complete tarsal coalition. Ankle osteoarthritis was diagnosed, and supportive treatment enabled the patient to return to an asymptomatic status and continue the duties of his employment. This case is presented to describe an adult patient with bilateral, massive tarsal coalition who was essentially asymptomatic until degenerative arthritic changes developed in one of his ankles.

Ontogenic differences in sexual size dimorphism across four plover populations

Sexual size dimorphism (SSD) among adults is commonly observed in animals and is considered to be adaptive. However, the ontogenic emergence of SSD, i.e. the timing of divergence in body size between males and females, has only recently received attention. It is widely acknowledged that the ontogeny of SSD may differ between species, but it remains unclear how variable the ontogeny of SSD is within species. Kentish Plovers Charadrius alexandrinus and Snowy Plovers C. nivosus are closely related wader species that exhibit similar, moderate (c. 4%), male-biased adult SSD. To assess when SSD emerges we recorded tarsus length variation among 759 offspring in four populations of these species. Tarsus length of chicks was measured on the day of hatching and up to three times on recapture before fledging. In one population (Mexico, Snowy Plovers), males and females differed in size from the day of hatching, whereas growth rates differed between the sexes in two populations (Turkey and United Arab Emirates, both Kentish Plovers). In contrast, a fourth population (Cape Verde, Kentish Plovers) showed no significant SSD in juveniles. Our results suggest that adult SSD can emerge at different stages of development (prenatal, postnatal and post-juvenile) in different populations of the same species. We discuss the proximate mechanisms that may underlie these developmental differences.

The centrodistal joint interosseous ligament region in the tarsus of the horse: Normal appearance, abnormalities and possible association with other tarsal lesions, including osteoarthritis

REASONS FOR PERFORMING STUDY

There have been no detailed descriptions of the radiological appearance of the centrodistal joint interosseous ligament region in horses with and without distal tarsal joint pain.

OBJECTIVES

To describe the normal radiological appearance of the centrodistal joint interosseous ligament region; to determine the prevalence of mineralisation or ossification of the interosseous ligament; and to describe radiological abnormalities surrounding the interosseous space and concurrent radiological abnormalities in the tarsus. The association between interosseous ligament region abnormalities and radiological evidence of osteoarthritis of the centrodistal joint was assessed.

STUDY DESIGN

Retrospective study.

METHODS

Case records and radiographs of all horses/ponies (n = 700) that underwent radiographic examination of one/both tarsi over 7 years were reviewed. Case history, height, bodyweight and cause(s) of lameness were recorded. Factors associated with abnormalities of the centrodistal interosseous ligament region were assessed using logistic regression analysis.

RESULTS

The normal interosseous space was an oval or circular-shaped radiolucent area bordered proximally and distally by a rim of bone of uniform opacity and thickness, which varied in thickness among animals. Abnormalities of the interosseous ligament region of the lame(r) limb were evident in 121/700 (17.3%; 95% confidence interval 14.5-20.1%) animals. Increasing bodyweight was associated with decreased odds of interosseous ligament region abnormalities. Forty-seven animals (6.7%; 95% confidence interval 4.9-8.6%) had radiological evidence of osteoarthritis of the centrodistal joint. A greater proportion of animals with interosseous ligament region abnormalities (36.4%) had radiological evidence of osteoarthritis of the centrodistal joint, compared to those with normal interosseous ligament regions (0.5%; P<0.001). Interosseous ligament region abnormalities and osteoarthritis of the centrodistal joint were not necessarily associated with distal tarsal joint pain.

CONCLUSIONS

There is an association between abnormalities of the centrodistal joint interosseous ligament region and osteoarthritis. Radiological evidence of abnormalities of the centrodistal intertarsal ligament region alone or in association with osteoarthritis may be present asymptomatically.

Detection of early osteoarthritis in the centrodistal joints of Icelandic horses: Evaluation of radiography and low-field magnetic resonance imaging

REASONS FOR PERFORMING STUDY

Validated noninvasive detection methods for early osteoarthritis (OA) are required for OA prevention and early intervention treatment strategies.

OBJECTIVES

To evaluate radiography and low-field magnetic resonance imaging (MRI) for the detection of early stage OA osteochondral lesions in equine centrodistal joints using microscopy as the reference standard.

STUDY DESIGN

Prospective imaging of live horses and imaging and microscopy of cadaver tarsal joints.

METHODS

Centrodistal (distal intertarsal) joints of 38 Icelandic research horses aged 27-29 months were radiographed. Horses were subjected to euthanasia approximately 2 months later and cadaver joints examined with low-field MRI. Osteochondral joint specimens were classified as negative or positive for OA using light microscopy histology or scanning electron microscopy. Radiographs and MRIs were evaluated for osteochondral lesions and results compared with microscopy.

RESULTS

Forty-two joints were classified OA positive with microscopy. Associations were detected between microscopic OA and the radiography lesion categories; mineralisation front defect (P<0.0001), joint margin lesion (P<0.0001), central osteophyte (P = 0.03) and the low-field MRI lesion categories; mineralisation front defect (P = 0.01), joint margin lesion (P = 0.02) and articular cartilage lesion (P = 0.0003). The most frequent lesion category detected in microscopic OA positive joints was the mineralisation front defect in radiographs (28/42 OA positive joints, specificity 97%, sensitivity 67%). No significant differences were detected between the sensitivity and specificity of radiography and low-field MRI pooled lesion categories, but radiography was often superior when individual lesion categories were compared.

CONCLUSIONS

Early stage centrodistal joint OA changes may be detected with radiography and low-field MRI. Detection of mineralisation front defects in radiographs may be a useful screening method for detection of early OA in centrodistal joints of young Icelandic horses.

Computed tomography assisted determination of optimal insertion points and bone corridors for transverse implant placement in the feline tarsus and metatarsus

OBJECTIVE

Describe optimal corridors for mediolateral or lateromedial implant placement in the feline tarsus and base of the metatarsus.

METHODS

Computed tomographic images of 20 cadaveric tarsi were used to define optimal talocalcaneal, centroquartal, distal tarsal, and metatarsal corridors characterized by medial and lateral insertion points (IP), mean height, width, length and optimal dorsomedial-plantarolateral implantation angle (OIA).

RESULTS

Talocalcaneal level: The IP were at the head of the talus and plantar to the peroneal tubercle of the calcaneus and OIA was 22.7° ± 0.3. Centroquartal level: The IP were at the centre of the medial surface of the central tarsal bone and dorsoproximal to the tuberosity of the fourth tarsal bone and OIA was 5.9° ± 0.06. Distal tarsal level: The IP were at the centre of the medial surface of the tarsal bone II and dorsodistal to the tuberosity of the fourth tarsal bone and OIA was 5.4° ± 0.14. Metatarsal level: The IP were at the dorsomedial surface of the proximal end of the metatarsal bone II and at the dorsolateral surface of metatarsal bone V and OIA was 0.5° ± 0.06. Significant positive correlation was found between body weight and the length of each corridor.

CLINICAL SIGNIFICANCE

Most of the corridors obtained in this study had a diameter between 1.5 mm and 2 mm with a length of 15 mm to 18 mm, which stresses the importance of their accurate placement.

Computed tomographic features of lesions detected in horses with tarsal lameness

REASONS FOR PERFORMING STUDY

Tarsal pain is a common cause of hindlimb lameness in horses. Diagnosis can usually be made with radiography and ultrasonography; however, in some cases, these techniques are inconclusive and additional imaging is necessary. No studies describing computed tomography (CT) features of different tarsal lesions in horses with tarsal lameness are reported.

OBJECTIVES

Our aims were as follows: 1) to characterise CT abnormalities in horses with tarsal lameness; 2) to compare CT findings with those from other imaging techniques; and 3) to assess whether CT can help to diagnose tarsal pathology.

STUDY DESIGN

Retrospective case series.

METHODS

Computed tomography of the tarsus was performed on 15 horses (n = 17 joints) with tarsal lameness. The horses were divided into 3 groups depending on the reason for CT examination, as follows: 1) other imaging techniques were inconclusive; 2) evaluation of a fracture; or 3) other imaging techniques showed tarsal lesions, and CT was performed to assess whether additional lesions were present.

RESULTS

Group 1 included 7 horses. Lesions detected with CT included subchondral cyst-like lesions (2 horses); an osteolytic lesion in the cochlea tibiae (one horse); degenerative changes of the distal tarsal joints (2 horses); osteolytic lesions tarsometatarsal joint (one horse); and sclerosis of the third tarsal bone with a lesion of the tarsometatarsal interosseous ligament (one horse). In this group, CT provided information on the character and extent of the lesion that was not available with other imaging techniques. Computed tomography revealed more information about the extent and complexity of the fracture than radiography in Group 2, whereas CT did not provide extra information in Group 3.

CONCLUSIONS

Focal lesions located between the tarsal bone surfaces are difficult or even impossible to detect with radiography and ultrasonography, but they can be detected and characterised with CT.

POTENTIAL RELEVANCE

Computed tomography of the tarsus should be considered when radiography and ultrasonography are inconclusive, or for further evaluation of tarsal fractures.

Relationship between hind limb lameness and radiographic signs of bone spavin in Icelandic horses in Sweden

A field study was designed to estimate the prevalence of hind limb lameness in a population of Icelandic horses in Sweden. All available Icelandic horses at 11 different farms within 150 km from Uppsala were examined once during a study period of 13 months. The relationship between hind limb lameness and radiographic signs of bone spavin (RSBS) was investigated. The rate of agreement between the outcome after palpation, motion evaluation and flexion test and radiographic examination was established. A total of 379 horses including 238 geldings, 125 mares and 16 stallions, with mean age 8.1 years (range 1-19 years) were examined by palpation of the medial aspect of the tarsal joints, motion evaluation and flexion test of the hind limbs. One dorsolateral-plantaromedial oblique radiographic view was recorded from each tarsus. Palpable abnormalities were found in 118 horses (31%). Forty-three horses (12%) were lame at presentation, 94 horses (25%) were positive on flexion test and 88 horses (23%) had RSBS. There was a significant relationship between palpable abnormalities, lameness, positive flexion test and RSBS. The proportion of joints with RSBS increased with increasing severity of physical findings. The proportion of lame limbs increased with increasing radiographic changes. The presence of palpable findings or positive flexion test was not influenced by the grading of radiographic changes. Using palpation, motion evaluation, and flexion test 75% of the horses with RSBS were identified. The rate of agreement between the clinical examination and the radiographic examination was 73%.

Prevalence and risk factors of bone spavin in Icelandic horses in Sweden: a radiographic field study

The present field study was performed to estimate the prevalence of radiographic signs of bone spavin (RSBS) and to evaluate some possible risk factors for RSBS in the Icelandic horse in Sweden. The survey included horses from 11 farms involving 379 horses, comprising 238 geldings, 125 mares and 16 stallions. Age ranged from 0 to 19 years with a mean age of 8.1 years. Horses were radiographed with a dorsolateral-plantaromedial-oblique projection of both tarsi. Information about age, gender, origin, working intensity, number of gaits and age when saddle broken were obtained by interviewing the owners. Features of each horse's conformation were obtained by measurement or inspection. Radiographic signs of bone spavin were found in 23% (n = 88) of the horses. Horses younger than 5 years did not show any RSBS and the prevalence increased from zero to 33% between 4 and 8 years of age. Using a multivariate logistic regression model increasing age and sickle hock conformation were found to be significantly associated with increased risk of RSBS. Age when saddle broken in combination with height at the withers also influenced the multivariate logistic regression model significantly.