Comparison of interfragmentary compression across simulated condylar fractures repaired using four techniques

IntroductionEquine condylar fractures are commonly repaired using cortex screws applied in lag fashion. Inadequate interfragmentary compression can lead to post-operative complications.MethodsLateral condylar fractures were simulated in 21 cadaver limbs (8 third metatarsals, 13 third metacarpals). In each limb, pressure-sensitive film (Prescale®, Fuji Photo Film Co.) was placed in each osteotomy prior to repair with 4.5 mm diameter cortex screws placed in lag fashion. Screws were placed in linear (L), triangular (T), linear plus a washer (LW) and sequentially tightened triangular configurations (TD1). All screws were tightened to a torque of 4 Nm. Pressure prints obtained were scanned using dedicated software (Fuji FPD-8010E, Fuji Photo Film Co.). A Bayesian Network (BN) model was developed to investigate the impact and interrelationship of each factor on interfragmentary compression. Sixty-three repairs (20*L, 24* T, 11*TD1, and 8*LW) performed on 21 limbs were included in the analysis.ResultsThe BN predicted mean contact area (±s.d.) for pressures within the operating range of the prescale film [≥2.5 Megapascals (MPa) ≤ 10 MPa] by L, T, TD1 and LW repairs were 403mm2 ± (140), 411 mm2 ± (120), 403 mm2 ± (120), and 366mm2 ± (70). The mean contact area (± s.d.) created by L, T, TD1 and LW repairs at pressures >10 MPa were 112 mm2 ± (48), 167 mm2 ± (67), 142 mm2 ± (50), and 100mm2 ± (27). When pressures ≥2.5 MPA to ≤10 MPa were considered, the construct (T or L), washer and screw tightening sequence variables had a very low effect on interfragmentary contact area. At pressures >10 MPa BN sensitivity findings were 16.3, 5.03, and 0.133% for construct, washer and screw tightening sequence. The BN model indicated that triangular repair configuration had a weak influence in the ≥2.5 MPa ≤ 10 MPa range and a moderate influence in the <10 MPa range, on interfragmentary compression. The addition of a washer and the screw tightening sequence had a weak influence on interfragmentary compression at all pressure ranges.DiscussionThe results show that triangular repairs create larger interfragmentary contact areas at greater interfragmentary pressure in simulated condylar fractures, however it is unknown if this results in improved repair stability in the clinical scenario

Effect of intra-articular administration of superparamagnetic iron oxide nanoparticles (SPIONs) for MRI assessment of the cartilage barrier in a large animal model

<div><p>Early diagnosis of cartilage disease at a time when changes are limited to depletion of extracellular matrix components represents an important diagnostic target to reduce patient morbidity. This report is to present proof of concept for nanoparticle dependent cartilage barrier imaging in a large animal model including the use of clinical magnetic resonance imaging (MRI). Conditioned (following matrix depletion) and unconditioned porcine metacarpophalangeal cartilage was evaluated on the basis of fluorophore conjugated 30 nm and 80 nm spherical gold nanoparticle permeation and multiphoton laser scanning and bright field microscopy after autometallographic particle enhancement. Consequently, conditioned and unconditioned joints underwent MRI pre- and post-injection with 12 nm superparamagnetic iron oxide nanoparticles (SPIONs) to evaluate particle permeation in the context of matrix depletion and use of a clinical 1.5 Tesla MRI scanner. To gauge the potential pro-inflammatory effect of intra-articular nanoparticle delivery co-cultures of equine synovium and cartilage tissue were exposed to an escalating dose of SPIONs and IL-6, IL-10, IFN-γ and PGE₂ were assessed in culture media. The chemotactic potential of growth media samples was subsequently assessed in transwell migration assays on isolated equine neutrophils. Results demonstrate an increase in MRI signal following conditioning of porcine joints which suggests that nanoparticle dependent compositional cartilage imaging is feasible. Tissue culture and neutrophil migration assays highlight a dose dependent inflammatory response following SPION exposure which at the imaging dose investigated was not different from controls. The preliminary safety and imaging data support the continued investigation of nanoparticle dependent compositional cartilage imaging. To our knowledge, this is the first report in using SPIONs as intra-articular MRI contrast agent for studying cartilage barrier function, which could potentially lead to a new diagnostic technique for early detection of cartilage disease.</p></div

Ex vivo effect of gold nanoparticles on porcine synovial membrane

Gold nanoparticles (AuNPs) have great potential as carriers for local drug delivery and as a primary therapeutic for treatment of inflammation. Here we report on the AuNP-synovium interaction in an ex vivo model of intra-articular application for treatment of joint inflammation. Sheets of porcine femoropatellar synovium were obtained post mortem and each side of the tissue samples was maintained in a separate fluid environment. Permeability to AuNPs of different sizes (5−52 nm) and biomarker levels of inflammation were determined to characterize the ex vivo particle interaction with the synovium. Lipopolysaccharide or recombinant human interleukin-1β were added to fluid environments to assess the ex vivo effect of pro-inflammatory factors on permeability and biomarker levels. The synovium showed size selective permeability with only 5 nm AuNPs effectively permeating the entire tissues’ width. This process was further governed by particle stability in the fluid environment. AuNPs reduced matrix metalloproteinase and lactate dehydrogenase activity and hyaluronic acid concentrations but had no effect on prostaglandin E(2) levels. Exposure to pro-inflammatory factors did not significantly affect AuNP permeation or biomarker levels in this model. Results with ex vivo tissue modeling of porcine synovium support an anti-inflammatory effect of AuNPs warranting further investigation

Quantitative radiographic interpretation and conservative treatment outcome in horses with osteoarthritis of the distal tarsal joints

Various radiographic rating scales (RRSs) for use in horses with distal tarsal joint osteoarthritis (DTJ OA) have been described in the literature but little information is available on their reliability in use. The aim of the first experiment of the study was to develop a RRS based on the consensus of experts in equine diagnostic imaging and orthopaedics, and to test the RRS for reliability. For this purpose 17 experts were invited to participate in an iterative consultation process (Delphi) designed to develop an agreement on the importance of radiographic features, reported to be consistent with DTJ OA. This process was conducted by electronic questionnaire. Rradiographic features for which an agreement was found, were incorporated in the RRS, which used a visual analogue scale. To test the RRS's reliability nine equine surgeons from two academic institutions applied the RRS on two occasions, and a verbal descriptive rating scale, to three sets of tarsal radiographs, each comprising 4 standard radiographic views. Reliability was assessed using Bland-Altman plots and by calculating the 95% agreement limits. ANOVA was used to identify significant interactions between the ratings of different assessors made from different views and on each occasion. Of 17 invited experts nine participated and completed the consultation process. Seven radiographic features were identified and used in the RRS. Rating of DTJ OA was different for the nine equine surgeons (assessors). The most precise assessor's second ratings were between 16 mm higher and 18 mm lower than the 1st. Significant variables were: "joint", "assessor" and "assessment" (univariable ANOVA); and "joint and assessor" and "assessor and assessment" (multivariable ANOVA). Reliability of the verbal descriptive rating scale was higher than for the RRS. The RRS developed for radiographic interpretation of DTJ OA as a result of the Delphi consultation process was less reliable than the use of a verbal descriptive rating scale. The repeatability of the RRS was not affected by the assessors' professional experience. In conclusion the RRS would not be useful clinically. Osteoarthritis of the DTJ, affecting the distal intertarsal (DIT) and tarsometatarsal (TMT) joint, is a common cause of hindlimb lameness in horses. Management options include i.a. treatment of the affected joints but only anecdotal information is available on the outcome. The aim of the second experiment of this study was to document short and long term treatment outcome in horses receiving i.a. methylprednisolone acetate (MPA; Depo-MedroneV) or triamcinolone acetonide (TR; Adcortyl) with or without hyaluronic acid (HA; Hyonate) as treatment of DTJ OA.Cases were selected by searching medical records. Inclusion criteria included ? 50% improvement in lameness following i.a. analgesia of the DIT and/or TMT joint and i.a. treatment with TR (+/- HA) or MPA. Change in lameness grade between examinations was tested using a Wilcoxon signed rank test for each horse, and between horses, grouped according to radiographic severity of DTJ OA and treatment, using a Mann Whitney test. Significance was set at P<0.05. Long term outcome was assessed using an owner telephone questionnaire. A positive treatment outcome was no lameness with the horse able to perform as intended without NSAID administration. Horses treated once with i.a. MPA or TR (+/- HA) showed improvement in hindlimb lameness after a median of 56 days (P<0.000). No difference was found between the use of MPA and TR (P=0.81). In horses treated twice, no further improvement was seen after the first treatment (P=0.141). Lameness in horses with diffuse increased radiopharmaceutical uptake (IRU) of the DTJ identified at scintigraphy tended to improve, in contrast to horses with focal IRU (Pfocal = 0.1; Pdiffuse = 0.032). Radiographic severity of OA did not affect outcome. 13/34 horses (38.2%) had a positive and 21/34 (61.8%) a negative long term outcome. It was concluded that intra-articular corticosteroids can be effective in the management of DTJ OA in horses

Subtotal Ovariohysterectomy Following Fetal Maceration and Pyometra in a Maiden Welsh Pony Mare

Fetal maceration and pyometra were diagnosed in a 16-year-old maiden Welsh pony mare. Due to anatomical and surgical difficulties encountered throughout treatment, previously reported techniques including both per-vaginum removal of fetal remnants and ovariohysterectomy were attempted and resulted in novel complications. Fetal bones were unable to be removed completely transcervically due to failure of cervical dilation despite repeated attempts. Subsequent surgical complications such as inadequate exposure of the uterus and incorporation of fetal bones into the uterine stump following ovariohysterectomy also occurred. This case highlights some of the difficulties in managing rare cases of mid-term fetal loss and retention that result in maceration. Ultimately, this may provide useful insights to practitioners when managing similar cases in future

Visually Assessing Equine Quality of Movement: A Survey to Identify Key Movements and Patient-Specific Measures

Outcome measures are essential for monitoring treatment efficacy. The lack of measures for quality of movement in equine physiotherapy and rehabilitation impairs evidence-based practice. To develop a new field-based outcome measure, it is necessary to determine movements most frequently observed during assessment of rehabilitation and performance management cases. An online survey of 81 equine sports medicine veterinarians and equine allied-health clinicians was conducted. The key movements identified included walk and trot on both firm and soft surfaces in a straight line and on a small circle, plus step back, hind leg cross-over, transitions and lunging at walk, trot and canter. The main barriers to observing some movements are access to suitable surfaces and the training level of the horse and handler. Subjective visual assessment of live or videoed horses was the most common method used to track progress of complex movements. The majority (82%) of survey participants agreed or strongly agreed that a modified Patient-Specific Functional Scale would be useful for measuring complex movements. Comments from all professions show a desire to have outcome measures relevant to their needs. This survey identified 24 in-hand movements, which can be used to form the foundation of a simple field-based outcome measure for quality of movement

Table_1_Comparison of interfragmentary compression across simulated condylar fractures repaired using four techniques.pdf

IntroductionEquine condylar fractures are commonly repaired using cortex screws applied in lag fashion. Inadequate interfragmentary compression can lead to post-operative complications.MethodsLateral condylar fractures were simulated in 21 cadaver limbs (8 third metatarsals, 13 third metacarpals). In each limb, pressure-sensitive film (Prescale®, Fuji Photo Film Co.) was placed in each osteotomy prior to repair with 4.5 mm diameter cortex screws placed in lag fashion. Screws were placed in linear (L), triangular (T), linear plus a washer (LW) and sequentially tightened triangular configurations (TD1). All screws were tightened to a torque of 4 Nm. Pressure prints obtained were scanned using dedicated software (Fuji FPD-8010E, Fuji Photo Film Co.). A Bayesian Network (BN) model was developed to investigate the impact and interrelationship of each factor on interfragmentary compression. Sixty-three repairs (20*L, 24* T, 11*TD1, and 8*LW) performed on 21 limbs were included in the analysis.ResultsThe BN predicted mean contact area (±s.d.) for pressures within the operating range of the prescale film [≥2.5 Megapascals (MPa) ≤ 10 MPa] by L, T, TD1 and LW repairs were 403mm2 ± (140), 411 mm2 ± (120), 403 mm2 ± (120), and 366mm2 ± (70). The mean contact area (± s.d.) created by L, T, TD1 and LW repairs at pressures >10 MPa were 112 mm2 ± (48), 167 mm2 ± (67), 142 mm2 ± (50), and 100mm2 ± (27). When pressures ≥2.5 MPA to ≤10 MPa were considered, the construct (T or L), washer and screw tightening sequence variables had a very low effect on interfragmentary contact area. At pressures >10 MPa BN sensitivity findings were 16.3, 5.03, and 0.133% for construct, washer and screw tightening sequence. The BN model indicated that triangular repair configuration had a weak influence in the ≥2.5 MPa ≤ 10 MPa range and a moderate influence in the DiscussionThe results show that triangular repairs create larger interfragmentary contact areas at greater interfragmentary pressure in simulated condylar fractures, however it is unknown if this results in improved repair stability in the clinical scenario.</p

In vitro comparison of linear vs triangular screw configuration to stabilize complete uniarticular parasagittal fractures of the proximal phalanx in horses

Objective To assess fracture gap reduction and stability of linear vs triangular 4.5‐mm lag screw repair of experimental, uniarticular, and complete forelimb proximal phalanx (P1) fractures. Study design Experimental. Sample population Fourteen equine cadaver limbs/horses. Methods Simulated fractures were repaired with 2 lag screws under 4‐Nm insertion torque (linear repair). Computed tomography (CT) imaging was performed with the leg unloaded and loaded to forces generated while walking. The fracture repair was revised to include 3 lag screws placed with the same insertion torque (triangular repair) prior to CT. The width of the fracture gap was assessed qualitatively by 2 observers and graded on the basis of gap measurements relative to the average voxel size at dorsal, mid, and palmar P1 sites. Interobserver agreement was assessed with Cohen's κ. The effect of repair type, loading condition, and measurement site on fracture gap grades was evaluated by using Kendall's τ‐b correlation coefficients and paired nonparametric tests. Significance was set at P ≤ .05. Results Agreement between loading and fracture gap widening was fair in triangular (κ = 0.53) and excellent in linear (κ = 0.81) repairs. Loading resulted in fracture gap distraction in linear repairs (Plinear = .008). Triangular repairs reduced fractures better irrespective of loading (Punloaded = .003; Ploaded < .001). The type of repair was not correlated with fracture gap grades at unloaded mid and loaded dorsal P1 sites. Conclusion Repair of uniarticular complete parasagittal fractures with a triangular screw configuration improved in vitro fracture gap reduction and stability. Clinical significance Triangular lag screw repair likely improves biomechanical conditions during postoperative weight bearing