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Objective: Silica is an environmental substance strongly linked with autoimmunity. The aim of this study was to assess the prevalence of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and renal limited vasculitis, in a northeastern region of France and to evaluate whether there was a geospatial association between the localization of quarries in the region and the prevalence of these AAVs., Methods: Potential AAV patients were identified using 3 sources: hospital records, immunology laboratories, and the French National Health Insurance System. Patients who resided in the Alsace region of France as of January 1, 2016 and who fulfilled the American College of Rheumatology criteria for GPA or the 2012 Chapel Hill Consensus Conference definitions for GPA or MPA were included. Incomplete case ascertainment was corrected using a capture-recapture analysis. The spatial association between the number of cases and the presence of quarries in each administrative entity was assessed using regression analyses weighted for geographic region., Results: Among 910 potential AAV patients, we identified 185 patients fulfilling inclusion criteria: 120 patients with GPA, 35 patients with MPA, and 30 patients with renal limited vasculitis. The number of cases missed by any source as estimated by capture-recapture analysis was 6.4 (95% confidence interval [95% CI] 3.6-11.5). Accordingly, the estimated prevalence in Alsace in 2016 was 65.5 GPA cases per million inhabitants (95% CI 47.3-93.0), 19.1 MPA cases per million inhabitants (95% CI 11.3-34.3), and 16.8 renal limited vasculitis cases per million inhabitants (95% CI 8.7-35.2). The risk of AAV was significantly increased in communities with quarries (odds ratio 2.51 [95% CI 1.66-3.80]), and geographic-weighted regression analyses revealed a significant spatial association between the proximity to quarries and the number of GPA cases (P = 0.039). In analyses stratifying the AAV patients by ANCA serotype, a significant association between the presence of quarries and positivity for both proteinase 3 ANCAs (P = 0.04) and myeloperoxidase ANCAs (P = 0.03) was observed., Conclusion: In a region with a high density of quarries, the spatial association between the presence of and proximity to quarries and the prevalence of AAVs supports the idea that silica may have a role as a specific environmental factor in this disease., (© 2021, American College of Rheumatology.)

Primary muscular echinococcosis is an uncommon localization of hydatid cysts. The nonspecific clinical presentation and possible post-therapeutic complications lead to problems for the diagnosis of this infection and the support of the patient. The authors describe an unusual case of double hydatid cyst of the vastus intermedius muscle. After a precise preoperative evaluation based on clinical, radiological and biological examinations, a surgical excision by pericystectomy combined with perioperative chemotherapy enabled the authors to treat the patient and to prevent postoperative complications. The diagnostic tools and the treatment of this particular type of echinococcosis are discussed.

Purpose: The measured resection technique and the gap-balancing technique are two philosophies used in total knee surgery. It is still unknown whether one or the other technique provides superior results when computer-assisted surgery is performed. We hypothesized that the gap-balancing technique improves joint stability because the technique relies primarily on the soft tissue., Methods: A prospective controlled study was performed in 116 patients using the tibia-first or femur-first technique. The Columbus(TM) total knee system and the Orthopilot(®) (Aesculap(®) AG, Tuttlingen, Germany) navigation system were used in all cases. Sixty-three patients were allocated to the femur-first technique (group F) and 53 patients to the tibial first technique (group T). The mean follow-up time was 11.4 ± 1.1 months. The KSS, KOOS and SF-36 were taken prior to surgery and at the time of follow-up for clinical assessment. Long-leg weight-bearing radiographs were performed to assess ligament alignment. Radiographs in varus and valgus stress were performed using the Telos(®)-Instrument (Telos(®) GmbH, Greisheim, Germany) under a force of 15 N at the time of follow-up for the assessment of medial-lateral stability. The nonparametric t test (Mann-Whitney U-test) was used in order to compare the ligament stability and the scores between group F and group T., Results: The lateral joint space opening for groups F and T was 3.4° ± 1.4° and 3.9° ± 1.7°, respectively (n.s.), and the medial joint space opening for groups F and T was 4° ± 1.4° and 4.1° ± 1.7°, respectively (n.s.). The femorotibial mechanical axis for groups F and T revealed 1.4° ± 1.2° and 0.7° ± 2.0° of varus, respectively (p = 0.138). The clinical assessment showed significant improvement according to KSS, KOOS and SF-36 in all subscales. Neither of the sores showed significant differences between the two groups., Conclusion: The surgeon should use his/her preferred surgical technique providing the implantation is performed with computer assistance. It remains unclear whether the same findings will occur after conventional surgery., Level of Evidence: II.

Several different biodegradable bone graft materials are in clinical or preclinical use for the repair of bone defects in orthopedics, maxillofacial surgery, and periodontics. This study tested the hypothesis that poly-D,L-lactide-co-glycolide copolymer (PLG) can be used as an effective carrier of recombinant human bone morphogenetic protein-2 (rhBMP-2) and that the composite has osteoinductive ability. Porous PLG rods were shredded to a particle size ranging from 250 to 850 microm. Active and inactive demineralized freeze-dried bone allografts (DFDBA) with a comparable particle size were used as positive and negative controls, respectively. PLG particles were treated with vehicle or with 5 or 20 microg rhBMP-2. DFDBA and PLG particles were placed in gelatin capsules, mixed with vehicle or rhBMP-2, and implanted at intramuscular sites in male Nu/Nu (nude) mice. Each mouse underwent bilateral implantation with implants of the same formulation, resulting in five groups of four mice per group: active DFDBA, inactive DFDBA, PLG, PLG + 5 microg rhBMP-2, and PLG + 20 microg rhBMP-2. After 56 days, the implants were recovered and processed for histology. Bone induction was assessed by use of a semiquantitative scoring system based on the amount of new bone formed in representative histological sections. Histomorphometry was also used to measure the area of new bone formed and the area of residual implant material. The results showed that active DFDBA induced the formation of ossicles containing new bone with bone marrowlike tissue, whereas inactive DFDBA or PLG particles alone did not induce new bone. The addition of rhBMP-2 to PLG particles resulted in new bone formation that had a greater bone induction score than active DFDBA. Moreover, the histomorphometric analysis showed that the addition of rhBMP-2 to PLG particles induced the formation of a greater area of new bone and bone marrowlike tissue than active DFDBA. The resorption of the PLG particles was markedly increased with the addition of rhBMP-2, suggesting that rhBMP-2 may attract and regulate resorptive cells at the implantation site. The results of the present study indicate that PLG copolymers are good carriers for BMP and promote the induction of new bone formation. Further, the PLG copolymers with rhBMP-2 had a greater effect in inducing new bone formation and resorbing the implanted material than active DFDBA alone.