Review of intra-articular local anaesthetic administration in horses: Clinical indications, cytotoxicity, and outcomes.

Equine practitioners frequently inject local anaesthetics (LA) intra-articularly in both diagnosis of lameness and for pain management intra- or post-operatively with synovial endoscopy. Recent reviews of the human and veterinary literature support the concept that chondrotoxicity of LA on joint tissues depends on the type of drug, dose administered, and duration of exposure. The purpose of this review is to summarise the current literature describing intra-articular local anaesthetic use, including both in vitro and in vivo studies, and to draw some comparisons to literature from other species where potential toxicity and duration of effect have been evaluated with the goal of advancing the field's understanding of intra-articular local anaesthetic use in horses, and indicating future directions for the field. The aggregate data available from all species, while generally sparse for horses, indicate that LA are rapidly cleared from the synovial fluid after injection, often within 30 min. In vitro data strongly suggest that lidocaine and bupivacaine are likely more chondrotoxic than other LA, although to what extent is still unknown, and cytotoxicity of LA may be mitigated through concurrent injection with HA, PRP, and drug combinations including nonsteroidal anti-inflammatories and opioids. The current body of in vitro research is not reflective of the in vivo environment, and further in vitro work, if performed, should focus on mimicking the native joint environment, utilising PK data and joint/injection volumes to replicate the native environment more accurately within the joint and the expected exposures to LA.

Objective evaluation for analgesia of the distal interphalangeal joint, the navicular bursa and perineural analgesia in horses with naturally occurring forelimb lameness localised to the foot.

BACKGROUND: The outcome and interpretation of intra-synovial diagnostic analgesia of the distal interphalangeal joint (DIPJ) and the navicular bursa (NB) remain in dispute, and no objective studies have been carried out to establish the percentage of improvement over time from these two analgesia techniques. OBJECTIVES: To investigate the qualitative and time-dependent outcome of DIPJ-A and NB-A in naturally occurring forelimb lameness. STUDY DESIGN: Case series. METHODS: Twenty-three clinical cases with forelimb lameness were evaluated objectively using a body mounted inertial sensor system (BMIS). Lameness was localised to the foot with a palmar digital nerve block and/or an abaxial sesamoidean nerve block on day 1, and analgesia of the DIPJ (DIPJ-A) and NB (NB-A) were performed on days 2 and 3. Improvement following perineural analgesia was measured after 10 min and intra-synovial blocks after 2-, 5- and 10-min. Horses with at least 70% improvement measured objectively after diagnostic analgesia were included in the study. RESULTS: There was no significant association between improvement following perineural analgesia and the DIPJ-A and NB-A. The mean improvement in the lameness differed between DIPJ-A and NB-A at 2 min (p < 0.001) and at 5 min (p = 0.04), and it was no longer observed after 10 min (p = 0.06). A positive NB-A produced a high degree of improvement that remained stable, whereas the DIPJ-A improved over time. MAIN LIMITATIONS: Perineural and intra-synovial analgesia were performed without contrast medium to assess the diffusion of mepivacaine. CONCLUSIONS: Our results suggest that perineural analgesia is not reliable enough to differentiate pain originating from DIPJ and NB. Early evaluation of the DIPJ-A and NB-A can determine the origin of the pain. An improvement following NB-A was constant over time, but an improvement following DIPJ-A varied by up to 10 min.

Differentially Expressed Proteins in Intra Synovial Compared to Extra Synovial Flexor Tendon Grafts in a Rabbit Tendon Transplantation Model.

 Uncomplicated healing of grafts for tendon reconstruction remains an unsolved problem in hand surgery. Results are limited by adhesion formation and decreased strength properties, especially within the tight fibro-osseous sheath of the digits. This is especially problematic when an extra synovial tendon graft is used to replace an intra synovial flexor tendon. Compositional differences are likely to play an important role in these processes. The aim of this study was, therefore, to compare protein expression in pair-matched intra synovial tendon grafts with extra synovial tendon grafts, using a rabbit tendon injury model. We hypothesized that there would be significant differences in proteins critical for response to tensile loading and adhesion formation between the two groups. Using mass spectrometry and multivariate statistical data analysis, we found tissue-specific differences in 22 proteins, where 7 explained 93% (R2) of the variation, with a prediction of 81% (Q2). Among the highest discriminating proteins were Galectin, Histone H2A, and Periostin, which were found in a substantially larger amount in the extra synovial tendons compared to the intra synovial tendons. These findings may contribute to improved understanding of the differences in outcome seen after tendon reconstruction using tendon grafts with intra synovial and extra synovial grafts.

Bone marrow mesenchymal stem cells do not enhance intra-synovial tendon healing despite engraftment and homing to niches within the synovium.

BACKGROUND: Intra-synovial tendon injuries display poor healing, which often results in reduced functionality and pain. A lack of effective therapeutic options has led to experimental approaches to augment natural tendon repair with autologous mesenchymal stem cells (MSCs) although the effects of the intra-synovial environment on the distribution, engraftment and functionality of implanted MSCs is not known. This study utilised a novel sheep model which, although in an anatomically different location, more accurately mimics the mechanical and synovial environment of the human rotator cuff, to determine the effects of intra-synovial implantation of MSCs. METHODS: A lesion was made in the lateral border of the lateral branch of the ovine deep digital flexor tendon within the digital sheath and 2 weeks later 5 million autologous bone marrow MSCs were injected under ultrasound guidance into the digital sheath. Tendons were recovered post mortem at 1 day, and 1-2, 4, 12 and 24 weeks after MSC injection. For the 1-day and 1-2-week groups, MSCs labelled with fluorescent-conjugated magnetic iron-oxide nanoparticles (MIONs) were tracked with MRI, histology and flow cytometry. The 4, 12 and 24-week groups were implanted with non-labelled cells and compared with saline-injected controls for healing. RESULTS: The MSCs displayed no reduced viability in vitro to an uptake of 20.0 ± 4.6 pg MIONs per cell, which was detectable by MRI at minimal density of ~ 3 × 104 cells. Treated limbs indicated cellular distribution throughout the tendon synovial sheath but restricted to the synovial tissues, with no MSCs detected in the tendon or surgical lesion. The lesion was associated with negligible morbidity with minimal inflammation post surgery. Evaluation of both treated and control lesions showed no evidence of healing of the lesion at 4, 12 and 24 weeks on gross and histological examination. CONCLUSIONS: Unlike other laboratory animal models of tendon injury, this novel model mimics the failed tendon healing seen clinically intra-synovially. Importantly, however, implanted stem cells exhibited homing to synovium niches where they survived for at least 14 days. This phenomenon could be utilised in the development of novel physical or biological approaches to enhance localisation of cells in augmenting intra-synovial tendon repair.

Non-operative Treatment for Acute Intra-synovial Sheath ACL Rupture / 中国运动医学杂志

Objective To evaluate the effectiveness of non-operative treatment for the acute intra-synovial sheath anterior cruciate ligament (ACL) rupture.Methods Twenty-eight patients diagnosed as the acute intra-synovial sheath ACL rupture at outpatient clinic between May 2014 and July 2016 were included.All patients were immobilized with knee braces for 6 weeks,followed by range of motion (ROM) training and partial to full weight-bearing of knees.All patients returned 3 months later for MRI scanning and those with the side-to-side difference of the anterior-posterior laxity less than 5 mm continued with non-operative treatment,followed up for MRI examination and clinical assessments 6 and 12 months later.Results Four patients dropped out because they didn't meet the stability criteria at 3 months after the treatment,3 of whom received surgical reconstruction and 1 with muscle strengthening training.Another patient received surgical reconstruction at 5 months due to re-injury.The remaining 23 patients achieved satisfactory results at 12 months after the treatment,with the average side-to-side difference of the anterior-posterior laxity of 2.1mm (0-4 mm),MRI good-to-excellent rate of 85.2％ (8 of Grade 1 and 15 of Grade 2),subjective IKDC (International Knee Documentation Committee) score of 92.71 (89.7-98.9),Lysholm score of 91.6 (86-95),and modified Larson score 96.4 (92-99).Conclusions Patients with the acute intra-synovial sheath anterior cruciate ligament (ACL) rupture showed satisfactory functional scores and objective stability and healing on MRI after the non-operative treatment.

Intra-synovial Ropivacaine and Morphine for Pain Relief after Total Knee Arthroplasty -A Prospective, Randomized, Double Blind Study-

PURPOSE: Several analgesic techniques are available for pain management after a major operation. MATERIALS AND METHODS: From December 2005 to February 2006, a prospective, double-blind study was performed involving 90 patients who had undergone a total knee arthroplasty. Patients were randomly divided into three equal groups (n=30). Demographic data, including age, height, weight, knee score, visual analogue scale (VAS), and range of flexion were evaluated preoperatively. Before wound closure, patients were given intra-synovial injections of the following solutions: patients in group I received 40mL of 300mg ropivacaine with 1:200,000 epinephrine and 5mg morphine; patients in Group II received 40mL of 300mg ropivacaine with epinephrine; and patients in Group III received 50mL normal saline as a control. All patients received an epidural patient-controlled analgesia (PCA) for 24 postoperative hours. Analgesic efficacy was evaluated using the VAS at intervals of 2, 4, 6, 12, 24, 32, 40, and 48 hours postoperatively. During this period, the side effects, the dosage of rescue analgesia required, and the range of knee flexion were recorded for each group. RESULTS: There were no significant differences among the three groups with regards to the VAS and the required dose of rescue analgesia (p > 0.05). None of the groups demonstrated significant differences in the range of knee flexion and the incidence of postoperative nausea and emesis (p > 0.05). CONCLUSION: Therefore, we found that ropivacaine, alone or with morphine, injected into the synovial tissue, along with an epidural PCA has no additional benefits in pain control after a total knee arthroplasty.

The Effects of Intra synovial Ropivacaine and Morphine Injection on Postoperative Pain After Total Knee Arthroplasty

PURPOSE: Pain control after total knee arthroplasty reduces total admission days and is important in improving post operative range of motion. This study evaluates the efficacy of intrasynovial injection of morphine and ropivacaine after total knee arthroplasty. MATERIALS AND METHODS: A prospective, double blinded and randomized study was performed in thirty two patients with American society of anesthesiology stage I or II who underwent one staged total knee arthroplasty for both knees simultaneously under spinal anesthesia. Demographic data (age, height, weight, gender distribution, Hospital for Special Surgery knee score, Knee society score, visual analogue scores (VAS) and range of motion were evaluated in all patients preoperatively. Before closure of the joint capsule, a local injective analgesia of 50mL including 0.5 ml 5 mg of HCL morphine, 40 mL 0.6% 300 mg ropivacaine and 0.25 mL of 1:200,000 epinephrine was injected into the synovium of one knee and 50 mL of normal saline was injected into the synovium of the opposite knee. Analgesic efficacy was evaluated by visual analogue scores (VAS) at intervals of 2, 4, 6, 12, 24, 32, 40 and 48 hours after operation. During this period, the amount of postoperative bleeding and range of motion were compared between both knees in the same patient. RESULTS: There were no statistically significant differences among both knees in regard to VAS at intervals of 2, 4, 6, 12, 24, 32, 40 and 48 hours after surgery (p>0.05). There were no statistically significant differences between the range of motion among both knees (p>0.05). CONCLUSION: On the basis of the results of this study, we do not recommend the routine use of postoperative intrasy-novial ropivacaine and morphine injection for the purpose of reducing pain in patients undergoing knee arthroplasty under spinal anesthesia with epidural patient controlled anesthesia.