Unicameral Bone Cyst in the Proximal Humerus with Secondary Infection in an 18 -Month-Old Foal

An 18-month-old warmblood filly was 4/5 lame on the front right limb at referral and showed severe swelling of the right shoulder region and pain during manipulation of the shoulder region. Radiography revealed a roundish 5 × 7 cm radiolucent area with defined borders within the greater tubercle and the presence of a fracture of the lateral tubercle associated with the cyst. Cellular blood count was 27,500 WBC/μL and serum biochemical analyses revealed fibrinogen of 855 mg/dL. The fractured bone was removed surgically; the cyst debrided and filled with autologous cancellous bone graft. Three and five weeks after surgery the filly was reoperated on because of an osseous sequestrum and a periostal defect on the distal dorsolateral aspect of the pastern of the right hind limb and a septic synovitis of the DFTS of the left hind limb. Fifteen month after surgery the filly was not lame and was introduced to training. Unicameral bone cysts (UBC) are well described lesions, often associated to pathologic fracture in the proximal humerus of children but, until present, no scientific report exists of UBC in the foal. The prompt surgical management had a favorable outcome

Arthroscopic removal of osteochondral fragments of the cervical articular process joints in three horses

Objective To report arthroscopic osteochondral fragment removal from the equine cervical spine articular process joints (APJs) including long-term follow-up. Study Design Case series. Animals Three Warmblood horses with forelimb lameness and/or reduced range of motion of the cervical spine with osteochondral fragments between the cervical vertebrae C5/C6 or C6/C7. Method Arthroscopy of the APJs of C5/C6 and C6/C7 was performed under general anesthesia. Following endoscopic evaluation of the joints, osteochondral fragments were removed using a rongeur. Results All horses recovered from anesthesia with no anesthetic or minor postanesthetic complications. One horse needed a second procedure for fragment removal. Fourteen to 31 months post-surgery the horses were sound for their intended use and neurological examination revealed no abnormalities. Conclusion Arthroscopic removal of osteochondral fragments can be performed safely in the equine cervical APJs of C5/C6 and C6/C7 resulting in a favorable long-term outcome. Clinical Significance Arthroscopic removal is a valid option for horses showing clinical signs that can be attributed to osteochondral fragments in the APJs of the neck

BMP2 and TGF-β Cooperate Differently during Synovial-Derived Stem-Cell Chondrogenesis in a Dexamethasone-Dependent Manner

Recent studies highlighting mesenchymal stem cell (MSC) epigenetic memory suggest that a different differentiation medium may be required depending on the tissue of origin. As synovial-derived stem cells (SDSCs) attract interest we aimed to investigate the influence of TGF-β1, BMP-2 and dexamethasone on SDSC chondrogenesis in vitro. We demonstrate that dexamethasone-free medium led to enhanced chondrogenic differentiation at both the mRNA and matrix level. The greatest COL2A1/COL10A1 ratio was detected in cells exposed to a combination medium containing 10 ng/mL BMP-2 and 1 ng/mL TGF-β1 in the absence of dexamethasone, and this was reflected in the total amount of glycosaminoglycans produced. In summary, dexamethasone-free medium containing BMP-2 and TGF-β1 may be the most suitable when using SDSCs for cartilage tissue regeneration

Diagnosis and outcome following tenoscopic surgery of the digital flexor tendon sheath in German sports and pleasure horses

Background Digital flexor tendon sheath (DFTS) pathology is an important cause of lameness in horses. The outcome after surgical treatment is variable and depends on the exact diagnosis. Objectives To (1) describe the prevalence of lesions associated with lameness caused by nonseptic DFTS tenosynovitis in a large population of German sports and pleasure horses; (2) determine the sensitivity and specificity of diagnostic imaging techniques for identifying lesions within the DFTS with tenoscopic diagnosis being the gold standard; (3) explore associations between tenoscopically diagnosed lesions and signalment, purpose, and limb affected; and (4) describe the outcome following DFTS tenoscopy with nonseptic DFTS tenosynovitis in this population. Study design Retrospective case series. Methods Medical records of horses admitted for tenoscopic surgery of nonseptic DFTS tenosynovitis between 2011 and 2020 were reviewed. Follow‐up information was obtained via telephone contact. Sensitivity and specificity of ultrasonography and contrast tenography were determined using tenoscopic diagnosis as gold standard and univariable analysis was used to explore associations between signalment, case history, and tenoscopic diagnosis. Results Medical records from 131 horses were retrieved, of which 8 horses had bilateral disease and 6 horses were presented for tenoscopy on two separate occasions (3 for tenoscopy in the same limb, 3 in a different limb), thus, making a total of 145 limbs. Lesions were most commonly diagnosed in the deep (DDFT; n = 55 limbs) and superficial (SDFT; n = 55 limbs) digital flexor tendons. Manica flexoria (MF) lesions were detected in 44 limbs and palmar/plantar annular ligament (PAL) constriction in 99 limbs. In 36 limbs, only one structure within the DFTS was injured, whereas in 109 limbs a combination of lesions was noted, the most common being the combination of a SDFT lesion with PAL constriction. All affected limbs were examined with diagnostic ultrasonography; contrast tenography was performed in 86 limbs. For diagnosis of MF and DDFT tears, tenography was more sensitive (89% [confidence interval, CI: 65.4%–95.2%]; 72% [CI: 46.4%–89.3%], respectively) than specific (64% [CI: 52.5%–77.6%]; 53% [CI: 42.2%–73.3%], respectively) whereas ultrasonography was more specific (92% [CI: 84.5%–96.3%]; 92% [CI: 83.6%–96.0%]) with lower sensitivity (64% [CI: 47.7%–77.2%]; 54% [CI: 39.5%–67.9%]). For SDFT lesions, ultrasonography was highly specific (94% [CI: 86.9%–97.9%]) with lower sensitivity (66% [CI: 51.3%–77.4%]). Follow‐up information following first surgery was obtained for 118 horses (132 limbs): 18 (15.3%) of 118 horses remained chronically lame, 40 (33.8%) performed at a reduced level and 60 (50.8%) performed at the same or higher level following rehabilitation after tenoscopy. Horses with DDFT lesions had the poorest outcomes with only 36.6% returning to the same or higher level of exercise. Main limitations Retrospective analysis of clinical records and subjective outcome assessment based on owner follow‐up with potential recall bias. Findings on diagnostic imaging are impacted by many factors including equipment quality and operator expertise and experience. Conclusion Diagnostic imaging techniques were complimentary and contrast tenography was sensitive and ultrasonography was specific for the diagnosis of MF and DDFT lesions. Following tenoscopic surgery for nonseptic tenosynovitis of the DFTS, approximately half the cases were able to return to preinjury level of exercise

Single-cut osteotomy for correction of a complex multiplanar deformity of the radius in a Shetland pony foal

Objective To describe the surgical correction of a multiplanar deformity of the radius in a pony using a single-cut osteotomy. Study design Case report. Animals A 9-week-old male Shetland pony foal with a bodyweight of 47 kg. Methods The foal presented with a complex multiplanar deformity of the right radius. A 3-dimensional model of the bone was created based on computed tomography (CT) imaging. To correct the deformity, the cutting plane for a single-cut osteotomy was calculated following the mathematical approach described by Sangeorzan et al. After osteotomy, the bone was realigned and stabilized with two 4.5 locking compression plates (LCPs). Results Recovery from surgery was uneventful, and the foal remained comfortable. A CT exam 15 weeks after surgery revealed that diaphyseal deformities improved substantially in procurvatum (from 8° to 1°), varus (from 27° to 0°), and rotation (30° to 5°). The operated radius was 2.1 cm shorter than the left. Eighteen-month follow up confirmed a functionally and cosmetically acceptable outcome. Conclusion The single-cut osteotomy resulted in the successful correction of a multiplanar equine long-bone deformity with a favorable outcome in a Shetland pony. Clinical significance Single-cut osteotomy is an alternative surgical technique for the correction of complex diaphyseal long-bone equine deformities. Computed tomography data and the possibility of printing 3D models provides a significant advantage for rehearsing the procedure and for evaluating the correction that was achieved

Modified toggle pin technique combined with prosthetic capsular reconstruction for surgical stabilization of coxofemoral luxation in a Shetland pony

Objective To describe open reduction and surgical stabilization of a coxofemoral luxation in a pony using a modified toggle pin technique and prosthetic joint capsule reconstruction without osteotomy of the greater trochanter. Animal A 2-year-old Shetland pony with a bodyweight of 167 kg. Study design Case report. Methods Radiographic examination confirmed craniodorsal luxation of the left coxofemoral joint. An open reduction with the aid of a pulley system was performed. A toggle pin was inserted through a bone tunnel extending from the level of the femoral shaft through the femoral head and the center of the acetabulum for the pin to be positioned on the medial wall of the acetabulum. FiberWire was subsequently passed through the cranial and caudal aspects of the acetabulum as well as a transverse tunnel in the femoral neck in a figure of 8 to facilitate capsular reconstruction. The pony was placed in a sling for 8 weeks and gradually returned to normal activity over 2 months. Results Postoperative radiographic examination confirmed the position of the femoral head in the acetabulum with the implants in place. On 2-year follow-up the pony was sound at walk and trot. Conclusion A combined intra- and extra-articular stabilization technique for coxofemoral luxation in a pony resulted in successful long-term reduction and excellent outcome

Findings consistent with equine proximal suspensory desmitis can be reliably detected using computed tomography and differ between affected horses and controls

The objective of this retrospective, observational, controlled study was to evaluate bone and soft tissue window CT images of the proximoplantar metatarsus III region in twenty horses with pain localized to the proximal suspensory ligament (PSL) and 20 horses with findings nonrelated to tarsal pain. All horses underwent CT and radiographic examination. Images were reviewed by three independent observers who graded the severity and localization of findings. Bone-related categories as well as soft tissue-related categories were evaluated. For the comparison of imaging findings in horses with and without proximal suspensory desmitis (PSD), mixed linear regression was performed. The intraclass correlation coefficient (ICC) was calculated to assess intraobserver agreement, and kappa statistics were employed to evaluate interobserver agreement. CT examination identified significantly more abnormalities in the diseased group. The scores for osseous exostosis (p = .015) and PSL enlargement (p = .004) were notably higher in PSD horses compared to controls. Intraobserver agreement was overall high (ICC .82–1.0), and interobserver agreement was substantial for the detection of mineralization (kappa = .61) and moderate for sclerosis (kappa = .43), exostosis (kappa = .43), and PSL enlargement (kappa = .48/.51). Measurements in the soft tissue window were significantly smaller than those in the bone window. Findings concurrent with PSD including osseous proliferation and sclerosis as well as soft tissue enlargement, mineralization, and avulsion can be reliably detected using CT. Findings from the current study supported the use of CT for evaluating horses with suspected PSD where high-field MRI is not available

Modified toggle pin technique combined with prosthetic capsular reconstruction for surgical stabilization of coxofemoral luxation in a Shetland pony

Objective To describe open reduction and surgical stabilization of a coxofemoral luxation in a pony using a modified toggle pin technique and prosthetic joint capsule reconstruction without osteotomy of the greater trochanter. Animal A 2-year-old Shetland pony with a bodyweight of 167 kg. Study design Case report. Methods Radiographic examination confirmed craniodorsal luxation of the left coxofemoral joint. An open reduction with the aid of a pulley system was performed. A toggle pin was inserted through a bone tunnel extending from the level of the femoral shaft through the femoral head and the center of the acetabulum for the pin to be positioned on the medial wall of the acetabulum. FiberWire was subsequently passed through the cranial and caudal aspects of the acetabulum as well as a transverse tunnel in the femoral neck in a figure of 8 to facilitate capsular reconstruction. The pony was placed in a sling for 8 weeks and gradually returned to normal activity over 2 months. Results Postoperative radiographic examination confirmed the position of the femoral head in the acetabulum with the implants in place. On 2-year follow-up the pony was sound at walk and trot. Conclusion A combined intra- and extra-articular stabilization technique for coxofemoral luxation in a pony resulted in successful long-term reduction and excellent outcome

Pharmacokinetic modelling of orally administered cannabidiol and implications for medication control in horses

Cannabidiol (CBD) products gain increasing popularity amongst animal owners and veterinarians as an alternative remedy for treatment of stress, inflammation or pain in horses. Whilst the use of cannabinoids is banned in equine sports, there is limited information available concerning CBD detection times in blood or urine. The aim of this study was to determine the pharmacokinetic properties of CBD following oral administration in the horse to assist doping control laboratories with interpreting CBD analytical results. Part 1: dose escalation study: Single oral administration of three escalating doses of CBD paste (0.2 mg/kg, n = 3 horses; 1 mg/kg, n = 3; 3 mg/kg, n = 5) with >7 days wash-out periods in between. Part 2: multiple dose study: oral administration of CBD paste (3 mg/kg, n = 6) twice daily for 15 days. Multiple blood and urine samples were collected daily throughout both studies. Following study part 2, blood and urine samples were collected for 2 weeks to observe the elimination phase. Concentrations of CBD, its metabolites and further cannabinoids were evaluated using gas-chromatography/tandem-mass-spectrometry. Pharmacokinetic parameters were assessed via two approaches: population pharmacokinetic analysis using a nonlinear mixed-effects model and non-compartmental analysis. AUC0–12 h and Cmax were tested for dose proportionality. During the elimination phase, the CBD steady-state urine to serum concentration ratio (Rss) was calculated. Oral CBD medication was well-tolerated in horses. Based on population pharmacokinetics, a three-compartment model with zero-order absorption most accurately described the pharmacokinetic properties of CBD. High volumes of distribution into peripheral compartments and high concentrations of 7-carboxy-CBD were observed in serum. Non-compartmental analysis identified a Cmax of 12.17 ± 2.08 ng/mL after single administration of CBD (dose: 3 mg/kg). AUC0–12 h showed dose proportionality, increase for Cmax leveled off at higher doses. Following multiple doses, the CBD terminal half-life was 161.29 ± 43.65 h in serum. Rss was 4.45 ± 1.04. CBD is extensively metabolized and shows high volumes of tissue distribution with a resulting extended elimination phase. Further investigation of the potential calming and anti-inflammatory effects of CBD are required to determine cut-off values for medication control using the calculated Rss

Computed tomographic study analysing functional biomechanics in the thoracolumbar spine of horses with and without spinal pathology

To better understand physiological and pathological movement patterns in the equine thoracolumbar spine, investigation of the biomechanics on a segmental level requires a constant moment. A constant moment along the spinal column means that the same torque acts on each vertebral segment, allowing the range of motion of different segments to be compared. The aims of this study were to investigate the range of motion of the equine thoracolumbar spine in horses with and without spinal pathology and to examine whether the pressure between the spinous processes depends on the direction of the applied moment. Thoracolumbar spine specimens (T8-L4) of 23 horses were mounted in a custom-made mechanical test rig to investigate spinal biomechanics during lateral bending, axial rotation, flexion and extension using computed tomographic imaging. Results were compared between horses with spondylosis, overriding spinous processes and specimens free of gross pathology. The interspinous space pressure was additionally determined using a foil sensor. The median lateral bending between T9 and L3 was 3.7°–4.1° (IQR 5.4°–8.0°). Maximum rotational movement with inconsistent coupled motion was observed at T9–T16 (p < 0.05). The dorsoventral range of motion was greatest in segments T9–T11 (p < 0.05). Spondylosis and overriding spinous processes restricted spinal mobility, depending on the severity of the condition. There was no significant difference in interspinous pressure during motion (p = 0.54). The biomechanical study confirmed that the range of motion of intervertebral joints depends on the anatomical position of the joint and the direction of the moment applied. Restricted mobility was evident in the presence of different grades of overriding spinous processes or spondylosis. A better understanding of equine spinal biomechanics in horses with spinal pathology facilitates individual rehabilitation