Radiation synovectomy by 188Re-Sulfide in haemophilic synovitis

Adverse reactions to therapeutic radiopharmaceuticals

Radiopharmaceuticals are drugs used in treatment or diagnosis that contain a radioactive part, usually a pharmaceutical part in their structure. Adverse drug reactions are harmful and unexpected responses that occur when administered at normal doses. Although radiopharmaceuticals are regarded as safe medical products, adverse reactions should not be ignored. More serious adverse reactions such as myelosuppression, pleural effusion, and death may develop in therapeutic radiopharmaceuticals due to their use at higher doses than those used in diagnosis. Therefore, monitoring adverse reactions and reporting them to health authorities is important. This review aims to provide information about adverse reactions that may be related to radiopharmaceuticals used in treatment.

Radiosynovectomy in haemophilic synovitis and arthropathy of the knee: A scoping review

INTRODUCTION

Radiosynovectomy is an established treatment for chronic synovitis in patients with haemophilia. Although its role in rheumatological diseases has diminished, it remains an accepted therapy for haemophilic synovitis.

AIM

The aim of this scoping review was to map and summarise the evidence surrounding radiosynovectomy in haemophilic knees, identify gaps in the literature and inform future research.

RESULTS

Forty-three manuscripts and abstracts were identified for this review. Evidence was limited to observational studies and Yttrium-90 was the most studied licensed radioisotope. Radiosynovectomy was associated with a reduction in bleeding frequency and pain, improvements in range of motion and a reduction in the use of factor replacement.

CONCLUSION

The literature reviewed lacks studies of sufficient methodological quality to permit systematic review and meta-analysis. Systematic review using risk of bias assessment for observational studies should be undertaken to better evaluate the efficacy and safety of radiosynovectomy. A causal relationship between RSV and key clinical outcomes remains undetermined.

Flexible use of commercial rhenium disulfide for various theranostic applications

Rhenium disulfide (ReS2) with distinct physicochemical properties has shown promising potential in disease theranostics, such as drug delivery, computed tomography (CT), radiotherapy, and photothermal therapy (PTT). However, the synthesis and post-modification of ReS2 agents for different application scenarios are time- and energy-consuming, which seriously hinders the clinical translation of ReS2. Herein, we proposed three facile excipient strategies for different theranostic applications of ReS2 just through the flexible use of commercial ReS2 powder. Three excipients, including sodium alginate (ALG), xanthan gum (XG), and ultraviolet-cured resin (UCR), were used to prepare different dosage forms of commercial ReS2 powder, like hydrogel, suspension, and capsule, respectively. These dosage forms of ReS2 with distinct characteristics showed great potential for second near-infrared window PTT against tumours, gastric spectral CT imaging, and functional evaluation of the digestive tract in vivo. In addition, these ReS2 formulations exhibited good biocompatibility both in vitro and in vivo, showing a promising prospect for clinical transformation. More importantly, the facile excipient strategies for commercial agents pave a bridge to the development and wide bioapplication of many other theranostic biomaterials.

Individual dose planning in radiosynoviorthesis treatment: Step by step

Radiosynoviorthesis (RSO) is a minimally invasive treatment aiming for the necrosis of the pannus tissue by the use of radionuclide. The method suggested here starts with the segmentation of the joint effusion, synovial thickness, and area of the synovial membrane using the 3D Slicer software. The last step is the estimated value of the activity to be injected without considering the leakage of the radiopharmaceutical into the articular cavity. It includes the S-values obtained by Monte Carlo simulation coupled with the calculated therapeutic distance (ST₉₀).

Rhenium-188 radiosynovectomy for chronic haemophilic synovitis: Evaluation of its safety and efficacy in haemophilic patients

INTRODUCTION

Radiocolloids labelled with less costly and more accessible radionuclides such as rhenium-188 are of interest to developing countries compared with those labelled with rhenium-186 and yttrium-90.

AIM

This study was aimed to evaluate the efficacy and safety of radiosynovectomy using rhenium-188 in patients with chronic haemophilic synovitis and recurrent hemarthrosis.

METHODS

In this quasi-experimental prospective study, 20 haemophilic patients were evaluated at preinjection, and at 1, 3, 6 and 12 months after injection. Magnetic resonance imaging (MRI) was done to measure synovial thickness and to calculate Denver score. Joint radiographs were taken to measure the Pettersson score. The Gilbert questionnaire, Functional Independence Score in Hemophilia (FISH) and visual analogue scale (VAS) for pain were completed, and the number of bleeding episodes and factor consumption were recorded at each follow-up visit.

RESULTS

The number of bleeding episodes, the amount of factor consumption per month, VAS pain scores and synovial thickness decreased significantly over time (P < .05). Gilbert and FISH scores showed significant improvement (P < .001). However, Pettersson score and Denver score showed no significant changes after injection. Minor complications including temporary pain and swelling occurred in 20% of patients, and no major complication was observed after rhenium-188 injection.

CONCLUSION

Our results indicated high clinical impact, efficacy, safety and low invasion of rhenium-188 in radiosynovectomy of haemophilic patients. Considering the availability and relatively low cost of rhenium-188 in developing countries, this can be a good treatment option for haemophilic patients with recurrent hemarthrosis, particularly when the synovial hypertrophy is not massive yet.

Rhenium Sulfide Nanoparticles as a Biosafe Spectral CT Contrast Agent for Gastrointestinal Tract Imaging and Tumor Theranostics in Vivo

Spectral computed tomography (CT) imaging as a novel imaging technique shows promising prospects in the accurate diagnosis of various diseases. However, clinically iodinated contrast agents suffer from poor signal-to-noise ratio, and emerging heavy-metal-based CT contrast agents arouse great biosafety concern. Herein, we show the fabrication of rhenium sulfide (ReS₂) nanoparticles, a clinic radiotherapy sensitizer, as a biosafe spectral CT contrast agent for the gastrointestinal tract imaging and tumor theranostics in vivo by teaching old drugs new tricks. The ReS₂ nanoparticles were fabricated in a one-pot facile method at room temperature, and exhibited sub-10 nm size, favorable monodispersity, admirable aqueous solubility, and strong X-ray attenuation capability. More importantly, the proposed nanoparticles possess an outstanding spectral CT imaging ability and undoubted biosafety as a clinic therapeutic agent. Besides, the ReS₂ nanoparticles possess appealing photothermal performance due to their intense near-infrared absorption. The proposed nano-agent not only guarantees obvious contrast enhancement in gastrointestinal tract spectral CT imaging in vivo, but also allows effective CT imaging-guided tumor photothermal therapy. The proposed "teaching old drugs new tricks" strategy shortens the time and cuts the cost required for clinical application of nano-agents based on existing clinical toxicology testing and trial results, and lays down a low-cost, time-saving, and energy-saving method for the development of multifunctional nano-agents toward clinical applications.

Discovery of rhenium and masurium (technetium) by Ida Noddack-Tacke and Walter Noddack

The history of the early identification of elements and their designation to the Mendeleev Table of the Elements was an important chapter in German science in which Ida (1896-1978) and Walter (1893-1960) Noddack played an important role in the first identification of rhenium (element 75, 1925) and technetium (element 43, 1933). In 1934 Ida Noddack was also the first to predict fission of uranium into smaller atoms. Although the Noddacks did not for some time later receive the recognition for the first identification of technetium-99m, their efforts have appropriately more recently been recognized. The discoveries of these early pioneers are even more astounding in light of the limited technologies and resources which were available during this period. The Noddack discoveries of elements 43 and 75 are related to the sub sequent use of rhenium-188 (beta/ gamma emitter) and technetium-99m (gamma emitter) in nuclear medicine. In particular, the theranostic relationship between these two generator-derived radioisotopes has been demonstrated and offers new opportunities in the current era of personalized medicine.

Dosimetry in Radiosynoviorthesis: 90Y VS. 153Sm

Although there are several radionuclides suitable for radiosynoviorthesis (RSO), not all of them can irradiate deeper synovium. Yttrium-90 (Y) is the beta radionuclide with more penetration range; therefore, it is predominantly used to treat knees. The aim of this paper is to highlight several dosimetry concepts to compare Y and Sm, also discussing the feasibility of implementing a dose planning methodology for both in RSO. The MCNPX Monte Carlo nuclear code version 2.6 was used for calculating S-values from which the activity to be injected into the joint was obtained. This activity is considered sufficient to deliver a 100-Gy absorbed dose in 1 mm of synovial tissue. The simulated mathematical model consisted of a system formed by several cylindrical slabs of 1-mm thickness, aligned consecutively. The different areas of the cylinder base simulate several synovial membrane sizes. The effective treatment range for each radionuclide was also calculated. Quantification of the synovial joint features (synovial thickness and synovial surface) by diagnostic imaging, such as magnetic resonance (MRI) combined with a Monte Carlo simulation, can be used to achieve a treatment planning strategy in RSO with the available radionuclides.

A new approach for radiosynoviorthesis: A dose-optimized planning method based on Monte Carlo simulation and synovial measurement using 3D slicer and MRI

PURPOSE

Recently, there has been a growing interest in a methodology for dose planning in radiosynoviorthesis to substitute fixed activity. Clinical practice based on fixed activity frequently does not embrace radiopharmaceutical dose optimization in patients. The aim of this paper is to propose and discuss a dose planning methodology considering the radiological findings of interest obtained by three-dimensional magnetic resonance imaging combined with Monte Carlo simulation in radiosynoviorthesis treatment applied to hemophilic arthropathy.

METHOD

The parameters analyzed were: surface area of the synovial membrane (synovial size), synovial thickness and joint effusion obtained by 3D MRI of nine knees from nine patients on a SIEMENS AVANTO 1.5 T scanner using a knee coil. The 3D Slicer software performed both the semiautomatic segmentation and quantitation of these radiological findings. A Lucite phantom 3D MRI validated the quantitation methodology. The study used Monte Carlo N-Particle eXtended code version 2.6 for calculating the S-values required to set up the injected activity to deliver a 100 Gy absorbed dose at a determined synovial thickness. The radionuclides assessed were: 90Y, 32P, 188Re, 186Re, 153Sm, and 177Lu, and the present study shows their effective treatment ranges.

RESULT

The quantitation methodology was successfully tested, with an error below 5% for different materials. S-values calculated could provide data on the activity to be injected into the joint, considering no extra-articular leakage from joint cavity. Calculation of effective treatment range could assist with the therapeutic decision, with an optimized protocol for dose prescription in RSO.

CONCLUSION

Using 3D Slicer software, this study focused on segmentation and quantitation of radiological features such as joint effusion, synovial size, and thickness, all obtained by 3D MRI in patients' knees with hemophilic arthropathy. The combination of synovial size and thickness with the parameters obtained by Monte Carlo simulation such as effective treatment range and S-value, from which is calculated the injected activity, could be used for treatment planning in RSO. Data from this methodology could be a potential aid to clinical decision making by selecting the most suitable radionuclide; justifying the procedure, fractioning the dose, and the calculated injected activity for children and adolescents, considering both the synovial size and thickness.

Radiosynovectomy in rheumatic diseases

Radiosynovectomy is a safe and repeatable treatment method of chronic synovitis with synovial overgrowth and refractory chronic or acute inflammatory joint effusion. It consist in the intraarticular administration of a radioactive isotope in the form of a colloid causing the extinguishing of active synovitis. The radiocolloid causes permanent irradiation of the synovium with beta ray electron beams, which ultimately leads to its fibrosis and extinguishes the inflammatory process destroying the joint.

The main indications for radiosynovectomy include chronic and acute arthritis in the course of systemic diseases, intraarticular bleeding in hemorrhagic diatheses (hemophilia), selected cases of osteoarthritis, recurrent effusions following surgery, e.g. arthroplasty, or other iatrogenic post-surgery complications causing arthritis. Radiosynovectomy is also performed in pigmented villonodular synovitis and crystal synovitis. The most common method used to determine the eligibility for radiosynovectomy is an ultrasound, which shows the location and activity of the thickened synovium. The administration of a radiocolloid into the joint, sheath or bursa should also be performed under the control of the ultrasound image, as this ensures a precise location of the puncture needle and full control of the isotope administration process. Clinical efficacy of radiosynovectomy depends on the proper qualification of patients for the procedure. The success rate of radiosynovectomy in common indications is 65–80%. It is confirmed by the visualization of avascular (fibrotic) synovium in follow-up ultrasound tests. The aim of this article is to present techniques and indications for the radiosynovectomy treatment.

Radiosynovectomy in haemophilia: long-term results of 500 procedures performed in a 38-year period

BACKGROUND

Radiosynovectomy (RS) can reduce the number of haemarthroses in chronic haemophilic synovitis. The purpose of this study was to assess the effectiveness of RS in terms of the objective improvement of five parameters (number haemarthroses, articular pain, degree of clinical synovitis, clinical score of the World Federation of Haemophilia (WFH), and radiological score of the WFH.

METHODS

In a 38-year period (1976-2013), five hundred radiosynovectomies were performed in 443 joints of 345 patients with haemophilia diagnosed with chronic synovitis. The mean patient age was 23.7 years (range, 6-53). The mean follow-up was 18.5 years (range: 6 months-38 years). The RS was carried out with either yttrium-90 or rhenium-186. We performed 1 to 3 injections (RS-1, RS-2, RS-3), with a 6-month interval between them.

RESULTS

RS resulted in significant improvement in all the parameters studied, except in the WFH radiologic score that showed no improvement. On average, the number of haemarthroses decreased by 64.1% and articular pain decreased by 69.4%. The degree of synovitis showed a reduction of 31.3%. The WFH clinical score revealed an improvement of 19%. The WFH radiological score showed no improvement. There were four complications (0.9%) of RS. Twenty-eight (6.3%) joints eventually had to be subjected to arthroscopic synovectomy or total knee replacement (TKR). No cancer was observed in this group of patients during the 38-year period.

CONCLUSIONS

Radiosynovectomy (RS) is an effective, safe, minimally invasive, well tolerated procedure in the long-term for the treatment of chronic haemophilic synovitis. Moreover, it is very easy to perform. The knee required more injections than the elbow or the ankle and more severe synoviums required a higher number of RS procedures.

Consecutive radiosynovectomy procedures at 6-monthly intervals behave independently in haemophilic synovitis

BACKGROUND

Previous studies on the same group of patients investigated here demonstrated the effectiveness of radiosynovectomy in the treatment of chronic haemophilic synovitis even if one, two or three radiosynovectomy procedures (RS-1, RS-2, RS-3) may be necessary. The purpose of this study was to determine whether the joints' response to each radiosynovectomy procedure behaved independently or not.

MATERIALS AND METHODS

One hundred and fifty-six radiosynovectomies were performed in 104 joints of 78 people diagnosed with chronic haemophilic synovitis. The patient's mean age was 18 years. Fifty-eight patients required radiosynovectomy in a single joint, whereas 20 received treatment in more than one joint. Of the 104 joints subjected to radiosynovectomy, 33 were elbows, 47 knees and 24 ankles. Radiosynovectomy was carried out with either yttrium-90 or rhenium-186 (1-3 injections with 6-month intervals between them). Of the 104 joints, 68 required a single injection of the radioisotope (RS-1), 20 required two injections (RS-2) and 16 required three injections (RS-3). In eight cases (7.6%), the affected joints eventually required surgery.

RESULTS

An analysis of seven variables (number of bleeding episodes, articular pain, range of motion in flexion and extension, muscle strength in flexion and extension, and synovial thickness by imaging) demonstrated that each consecutive radiosynovectomy behaves independently in haemophilic synovitis.

DISCUSSION

Each consecutive radiosynovectomy behaves independently in haemophilic synovitis. This finding had not been documented in the literature before the present study.

Radionuclide synovectomy in haemophilic joints

Chronic synovitis often occurs in people with haemophilia. Untreated chronic haemophilic synovitis affects the metabolism of chondrocytes, thus leading to haemophilic arthropathy. A recently introduced therapeutic protocol includes radiation synovectomy (RS), a safe and cost-effective therapeutic method, which has given satisfactory results in 75% of haemophiliacs with chronic hypertrophic synovitis. Because of its efficacy, we will discuss additional recommendations on the use of RS as a method of choice. The focus of this review is haemophilic arthropathy treatment, including its aetiopathogenesis, reasons for RS indication and its mechanism of action, and use of radioisotopes and other agents for treatment.

Micronucleus evaluation for determining the chromosomal breakages after radionuclide synovectomy in patients with hemophilia

OBJECTIVE

To investigate the genotoxic effects of (90)Y and (186)Re in patients with hemophilia who were undergoing radionuclide synovectomy (RS) procedure in the last 3 years.

METHODS

Nineteen patients were enrolled in the study. Most of the patients (n = 17) were hemophilia-A (mean age 20.6 ± 10.5 years) and 18 patients (mean age 22.6 ± 10.6 years) with hemophilia who were not exposed to RS procedure were included in the study as control group. Most cases in the control group (n = 13) were hemophilia-A. (90)Y for knee joints and (186)Re for elbow or ankle joints were used to perform RS in hemophilic patients. We studied the micronucleus (MN) test on peripheral blood lymphocytes as an indicator of radiation-induced cytogenetic damage and calculated nuclear division index.

RESULTS

There was no significant difference between the patients with and without RS with respect to MN values. However, both values obtained in RS-exposed patients and control group were much elevated than values reported in literature from healthy controls. The mean MN values of patients below 20 years old were much lower but not significant than those above 20 years old. MN frequencies between (186)Re and (90)Y groups were also analyzed, and no significant difference was observed. Hemophilia patients who were treated with (186)Re showed higher levels of MN compared to patients treated with (90)Y although the difference was not significant.

CONCLUSIONS

Radioisotope synovectomy (RS) seems to be a safe procedure not causing a significant genotoxic effect on hemophilic patients, however, further studies including larger series of patients are needed to better understand the effects of RS on patients' health.

Radiosynovectomy in hemophilia: quantification of its effectiveness through the assessment of 10 articular parameters

BACKGROUND

Radiosynovectomy (RS) can reduce the number of hemarthroses in chronic hemophilic synovitis. The purpose of this study was to quantitatively assess the effectiveness of RS in terms of the objective improvement of ten articular parameters.

METHODS

One-hundred and fifty-six radiosynovectomies were performed in 104 joints of 78 hemophiliacs diagnosed with chronic synovitis. The mean patient age was 18 years. The RS was carried out with either yttrium-90 or rhenium-186 (1-3 injections with a 6-month interval between them).

RESULTS

RS resulted in significant improvement in nine of the 10 variables studied, namely in the number of episodes of hemarthrosis, articular pain, range of motion (ROM) in flexion. ROM in extension, muscle strength (MS) in flexion, MS in extension, the degree of synovitis detected on clinical examination, the size of the synovium as measured by means of imaging techniques (in millimeters), the clinical scale developed by the World Federation of Haemophilia (WFH), and the radiologic scale of the WFH. The tenth parameter, the WFH radiologic score, showed no improvement. The other nine parameters studied improved independently for each one of the intra-articular injections of the radioisotope.

CONCLUSIONS

Categorization of the variables with regard to the degree of improvement achieved showed that the number of episodes of hemarthrosis and the severity of pain were the variables associated with the greatest improvement, with a 70% decrease in the amount of bleeding and in the level of pain experienced by the patient. The reduction of articular bleeding after RS was 67.6% when RS-1 was used, 62.1% with RS-2 and 61.2% with RS-3. Synovial hypertrophy as assessed clinically and by imaging techniques also showed a reduction of 30% and 39%, respectively. The WFH clinical scale revealed an improvement of around 19%. MS also improved in flexion and extension (7.9% and 8.2% improvement, respectively). ROM showed a slight but non-significant improvement.

Musculoskeletal complications of hemophilia

The most important clinical strategy for management of patients with hemophilia is the avoidance of recurrent hemarthroses by means of continuous, intravenous hematological prophylaxis. When only intravenous on-demand hematological treatment is available, frequent evaluations are necessary for the early diagnosis and treatment of episodes of intra-articular bleeding. The natural history of the disease in patients with poorly controlled intra-articular bleeding is the development of chronic synovitis and, later, multi-articular hemophilic arthropathy. Once arthropathy develops, the functional prognosis is poor. Treatment of these patients should be conducted through a comprehensive program by a multidisciplinary hemophilia unit. Although continuous prophylaxis can avoid the development of the orthopedic complications of hemophilia still seen in the twenty-first century, such a goal has not, so far, been achieved even in developed countries. Therefore, many different surgical procedures such as arthrocentesis, radiosynoviorthesis (radiosynovectomy) (yttrium-90, rhenium-186), tendon lengthenings, alignment osteotomies, joint arthroplasties, removal of pseudotumours, and fixation of fractures are still frequently needed in the care of these patients.

Characterization of Re-188–Sn microparticles used for synovitis treatment

Rhenium-188 labeled tin (Sn) microparticles were developed for pain palliation therapy in the patients suffering from synovitis with acute pain. The rhenium tin microparticles were prepared using stannous chloride and freshly eluted (188)ReO(4)(-) from (188)W/(188)Re generator. The aggregated colloidal particles, packed in a spherical form after boiling for 90-120min were analyzed using electron microscope. The size, surface morphology and stability of microparticles were analyzed by changing temperature and volume conditions. The small colloidal particles clustered and formed spherical microparticles. The 90% of microparticles were in 5-10microm range, after 90min and 120min of boiling. The radiolabeling efficiency was improved to 98% after centrifugation for 10min at 3500rpm. The formulations were stable but the increase in volume had inverse effect on labeling efficiency. No leak was observed from knee area up to 24h with 15-20mCi injection of (188)Re-Sn microparticles. The relief in treated patients, from the pain and inflammation, was observed clinically and by (99m)Tc-MDP perfusion scan.

Radiation synovectomy using 188Re-tin colloid improves knee synovitis as shown by MRI in refractory rheumatoid arthritis

BACKGROUND

Radiation synovectomy is a useful local treatment for patients with refractory synovitis. We previously demonstrated the efficacy and safety of Re-tin colloid for treating rheumatoid arthritis patients with refractory knee synovitis. This open-label, prospective controlled study investigates magnetic resonance imaging (MRI) changes as well as clinical response in knees after receiving different radioactivities of intra-articular Re-tin colloid.

METHODS

Sixteen patients with rheumatoid arthritis refractory to intra-articular corticosteroid therapy were treated with intra-articular injection of Re-tin colloid (555 MBq in six patients, 740 MBq in five, and 925 MBq in five). Contralateral knees were used as controls. Treatment efficacy and safety were evaluated 1, 3 and 6 months later. We compared the changes of synovial thickening and joint effusion between baseline and 6 months. Synovial thickness was measured by gadolinium-enhanced MRI.

RESULTS

Pain intensities on a visual analogue scale were significantly lower (median pain reduction, 78.9%; P=0.0001), joint swelling improved (median, -1.5; P=0.001), range of motion increased (median, 6 degrees , P=0.005), and joint tenderness decreased (median, -1; P=0.005) in treated knees after 6 months. The control knees did not show any significant clinical improvement. At 6 months after therapy, synovial thickening of treated knees improved in 87.5% of patients (P<0.001), and synovial thicknesses were significantly decreased in treated knees (P=0.0067). Furthermore, reduction in synovial thickness was most noticeable in the group treated with 925 MBq (P=0.007). No abnormalities in leukocyte or platelet counts, liver function tests, or urine analysis were observed.

CONCLUSION

Radiation synovectomy using Re-tin colloid in refractory rheumatoid arthritis patients improved MRI findings as well as clinical parameters.

Long-term evaluation of radioisotope synovectomy with Yttrium 90 for chronic synovitis in Turkish haemophiliacs: Izmir experience

Since 2001 we have performed 105 radioisotope synovectomy (RS) in 65 children and young adults, age ranging from 3 to 25 years with a average of 15 years in Ege University Hospital, Izmir, Turkey. One fourth of cases were below 10 years of age. All patients had severe haemophilia A and B. Ten patients (17 joints) had high responder inhibitor. We prefer to use Yttrium 90 for all joints (5 mCi for knees; 2 mCi for others). The knees were injected in 56 cases, elbows in 24 cases, ankles in 23 cases and shoulders in two cases. Steroid injections were not preferred as the principle drug of choice. Mean follow-up period after procedure was 2 years (range: 6 months to 3.5 years). All inhibitor patients had satisfactory results. The best results were obtained in elbows than knees and ankles. Excellent rates (no bleeding) were observed in grade-II synovitis 84% for knees, 93% for elbows and 50% for ankles. Because of the excellent and good response (bleeding reduction to 75%), rates were 100% for knees and elbows and 92% for ankles. In six cases, repeated injections were given at 6-month interval and all of them had good results. The grading of synovitis seems to be an important parameter than the age of the patient. Even in patients below 10 years of age, outcomes are not satisfactory in all joints with grade-III vs. grade-II synovitis (12% vs. 73%). No serious complications were observed during and after procedure except two cases. A mild and transient inflammatory reaction was observed in the ankle. There was a minimal radioisotope leakage to superficial skin in the elbow. RS seems to be a safe and effective treatment for chronic synovitis causing recurrent joint bleedings.