Faculty Bibliography

BACKGROUND/OBJECTIVE/OBJECTIVE:Arthrocentesis of the noneffusive knee is challenging. We hypothesized (1) pneumatic compression of the noneffusive knee would improve arthrocentesis, and (2) the increased synovial fluid yield would be diagnostically useful. METHODS:One hundred and thirty consecutive patients with a painful but clinically noneffusive knee underwent arthrocentesis. Arthrocentesis was performed with and without pneumatic compression and fluid volumes from each were measured. Successful arthrocentesis was defined as a fluid yield ≥1.0 mL. Synovial fluid samples were analyzed for total nucleated cell (TNC) count, TNC differential, the presence of crystals by polarized microscopy, and bacteria by culture. RESULTS:Arthrocentesis of the noneffusive joint was successful (≥1.0 mL) in 15.4% (20/130) with conventional arthrocentesis and in 53.8% (70/130) with pneumatic compression (OR: 6.4; CI: 3.6-11.6; p=0.0001). Pneumatic compression increased synovial fluid yield: conventional arthrocentesis: 0.5±1.1 mL, compression: 2.8±3.5 mL [2.3±3.0 mL increase (+460%), 95% CI: -2.9<-2.3<-1.7 mL; p=0.0001]. Synovial fluids were abnormal in 60.0% (42/70) of aspirated knees. Mean TNC was 2746±10,741 cells/mm3, including 40.0% normal fluid (TNC/mm3<200), 49.2% noninflammatory fluid (TNC/mm3 ≥200 but <2000), 10.8% inflammatory fluid (TNC/mm3 ≥2000), 1.5% hemorrhagic fluid, and 10% fluids with crystals that changed the diagnosis and subsequent therapy. CONCLUSIONS:Pneumatic compression-assisted arthrocentesis enables the successful collection of synovial fluid in the clinically noneffusive symptomatic knee. The majority of extracted synovial fluids are abnormal, indicating inflammatory arthritis, noninflammatory arthritis, or previously unrecognized crystal-associated disease. Pneumatic compression-assisted arthrocentesis is useful in the evaluation of the clinically noneffusive symptomatic knee.

AIM/OBJECTIVE:Complete arthrocentesis of the effusive knee ameliorates patient pain, reduces intra-articular and intraosseous pressure, removes inflammatory cytokines, and has been shown to substantially improve the therapeutic outcomes of intra-articular injections. However, conventional arthrocentesis incompletely decompresses the knee, leaving considerable residual synovial fluid in the intra-articular space. The present study determined whether external pneumatic circumferential compression of the effusive knee permitted more successful arthrocentesis and complete joint decompression. METHODS:Using a paired sample design, 50 consecutive effusive knees underwent conventional arthrocentesis and then arthrocentesis with pneumatic compression. Pneumatic compression was applied to the superior knee using a conventional thigh blood pressure cuff inflated to 100 mm Hg which compressed the suprapatellar bursa and patellofemoral joint, forcing fluid from the superior knee to the anterolateral portal where the fluid could be accessed. Arthrocentesis success and fluid yield in mL before and after pneumatic compression were determined. RESULTS:Successful diagnostic arthrocentesis (≥3 mL) of the effusive knee was 82% (41/50) with conventional arthrocentesis and increased to 100% (50/50) with pneumatic compression (P = .001). Synovial fluid yields increased by 144% (19.8 ± 17.1 mL) with pneumatic compression (conventional arthrocentesis; 13.7 ± 16.4 mL, pneumatic compression: 33.4 ± 26.5 mL; 95% CI: 10.9 < 19.7 < 28.9 mL, P < .0001). CONCLUSIONS:Conventional arthrocentesis routinely does not fully decompress the effusive knee. External circumferential pneumatic compression markedly improves arthrocentesis success and fluid yield, and permits complete decompression of the effusive knee. Pneumatic compression of the effusive knee with a thigh blood pressure cuff is an inexpensive and widely available technique to improve arthrocentesis outcomes.

Botulism is caused by a potent neurotoxin that blocks neuromuscular transmission, resulting in death by asphyxiation. Currently, the therapeutic options are limited and there is no antidote. Here, we harness the structural and trafficking properties of an atoxic derivative of botulinum neurotoxin (BoNT) to transport a function-blocking single-domain antibody into the neuronal cytosol where it can inhibit BoNT serotype A (BoNT/A1) molecular toxicity. Post-symptomatic treatment relieved toxic signs of botulism and rescued mice, guinea pigs, and nonhuman primates after lethal BoNT/A1 challenge. These data demonstrate that atoxic BoNT derivatives can be harnessed to deliver therapeutic protein moieties to the neuronal cytoplasm where they bind and neutralize intracellular targets in experimental models. The generalizability of this platform might enable delivery of antibodies and other protein-based therapeutics to previously inaccessible intraneuronal targets.

Background/Purpose : Arthrocentesis is an essential procedure in diagnosing inflammatory and septic arthritis and is a basic procedure for intra-articular therapy, including therapeutic arthrocentesis and intra-articular injection. Complete arthrocentesis before injection of corticosteroid or hyaluronan confirms the diagnosis, reduces the possibility of superimposed infection, reduces patient pain, and improves response to the injected drug. Meehan et al and others have demonstrated that constant external compression of the knee improves arthrocentesis yield and outcomes. As a quality improvement process, we used a pneumatic compression cuffto apply constant compression to the flexed knee to remove the operator's hands from potential needlestick, mobilize synovial fluid, and permit more complete arthrocentesis. Methods : 25 consecutive painful knees (11 OA, 9 OA/RA, 4 RA, 1 RA/septic joint) underwent arthrocentesis performed conventionally and with pneumatic compression. The mean age of the population was 61.3+/-14.3 years with male:female of 1: 2.1. Pre-procedural pain according to the 10 cm Visual Analogue Pain Scale (VAS) was 8.0+/-1.2 cm.The quality intervention was designed as a paired study in the same knee: that is, first conventional arthrocentesis in the flexed knee position using the inferolateral approach was performed and quality and outcome measures were obtained. After fluid return ceased, a pneumatic leg cuff, which was placed over the suprapatellar bursa prior to starting the procedure, was inflated to 60 millimeters Hg. Arthrocentesis was then re-attempted, and quality measures were obtained once again. Arthrocentesis in flexed knee position, using a pneumatic leg cuffArthrocentesis yield from the knee with and without pneumatic compression Results : Procedural pain according to the 10 cm VAS was 3.9+/-2.8cm and post-procedural pain was 1.0+/-1.3 cm. In 25 painful knees, conventional arthrocentesis yield was 7.8+/-18.2 ml and using pneumatic compression was 14.3+/-27.9 ml, an 84.1% increase (Figure 2). When the 13 effusive knees were analyzed separately, conventional arthrocentesis yield was 18.2+/-22.7 ml and using pneumatic compression was 27.9+/-28.6 ml, a 53.3% increase. The mean enhanced arthrocentesis yield reported here with the pneumatic compression in the flexed knee is similar to improved fluid yield that we have reported previously of 16.7+/-11.3 ml with elastomeric compression of the flexed knee (p = 0.69) and both are similar to the 16.9+/-15.7 ml arthrocentesis yield that was reported in conventional extended knee arthrocentesis (p = 0.69) (Yaqub et al 2018). Conclusion : The technique of constant compression using a pneumatic cuffmobilizes residual synovial fluid and improves arthrocentesis success. The use of a pneumatic leg cuffin the flexed knee is a low-cost quality improvement technique that can readily be incorporated into clinical musculoskeletal practice and is particularly useful for performing arthrocentesis in patients in the sitting position, confined to wheelchairs, or with flexion contractures of the knee. Further, since the pneumatic cuffis spatially superior to the inferolateral portal at the puncture site, errant synovial fluid flows down the leg away from the cuffand does not contaminate the device unlike compression devices used in the extended knee positioning

INTRODUCTION/OBJECTIVES/OBJECTIVE:We hypothesized that mechanical compression of the knee in rheumatoid arthritis (RA) would mobilize occult extractable fluid and improve arthrocentesis success. METHODS:Sixty-seven consecutive knees with RA and 186 knees with OA and were included. Conventional arthrocentesis was performed and success and volume (milliliters) determined; the needle was left intraarticularly, and mechanical compression was applied with an elastomeric knee brace. Arthrocentesis was then resumed until fluid return ceased. Fluid was characterized as to volume and cell counts. RESULTS:In the RA, knee mechanical compression decreased failed diagnostic arthrocentesis from 56.7% (38/67) to 26.9% (18/67) (- 47.4%, p = 0.003) and increased absolute arthrocentesis yield from 4.7 ± 10.3 ml to 9.8 ± 9.8 ml (108% increase, 95% CI - 8.5 < - 5.1 < - 1.7 p = 0.0038). Total extractable fluid yield was 96% greater in RA (9.8 ± 9.8 ml) than OA (5.0 ± 9.4 ml, p = 0.0008), and occult extractable fluid was 77% greater in RA than OA (RA 5.3 ± 8.7 ml, OA 3.0 ± 5.5 ml, p = 0.046). Large effusions versus small effusions in RA demonstrated increased neutrophils in synovial fluid (p = 0.04) but no difference in radiologic arthritis grade (p = 0.87). In contrast, large effusions versus small effusions in OA demonstrated no difference in neutrophils in synovial fluid (p = 0.87) but significant different radiologic arthritis grade (p = 0.04). CONCLUSION/CONCLUSIONS:Mechanical compression improves the success of diagnostic and therapeutic knee arthrocentesis in both RA and OA. Large effusions in RA are associated with increased neutrophil counts but not arthritis grade; in contrast, large effusions in OA are associated with more severe arthritis grades but not increased neutrophil counts. Key points • Mechanical compression of the painful knee improves arthrocentesis success and fluid yield in both rheumatoid arthritis and osteoarthritis. • The painful rheumatoid knee contains approximately 100% more fluid than the osteoarthritic knee. • Large effusions in the osteoarthritic knee are characterized by higher grades of mechanical destruction but not increased neutrophil counts. • In contrast, large effusions in the rheumatoid knee are characterized by higher synovial fluid neutrophil counts but not the grade of mechanical destruction, indicating different mechanisms of effusion formation in rheumatoid arthritis versus osteoarthritis.

Background: Botulinum neurotoxins (BoNTs) pose serious military and civilian mass casualty threats with potential to rapidly overwhelm medical resources. Currently, the only FDA-approved treatment for botulism is infusion of antibody-based antitoxins to neutralize BoNT that circulates in the bloodstream. Presently, there is no treatment to inactivate the protease activity of BoNTs within the neuron. Here, we describe a first-in-kind treatment approach to block the protease activity of BoNT at the site of intoxication. The technology is based on "atoxic" derivatives of botulinum neurotoxins (serotypes A and C) that can maintain their natural biological trafficking properties and deliver single-chain antibodies to inhibit the protease activity of BoNTs. This report focuses on in vitro and in vivo studies of a treatment candidate for BoNT/A, termed Cyto-111. Method(s): In vitro studies were performed using E18 rat cortical neurons. In vivo studies were performed in: (1) CD-1 female mice (22 to 27 g); (2) Hartley guinea pigs (250 to 350 g); and (3) adult Rhesus macaques (5 to10 kg). Result(s): In vitro, Cyto-111 binds and inhibits the light chain of BoNT/A. When administered intraperitoneally (ip), Cyto-111 traffics to the neuromuscular junction of the diaphragm, where it localizes with presynaptic markers. In a murine postsymptomatic model of BoNT/A toxemia, treatment ip or intravenously with Cyto-111 prevented death at stages of disease that are completely refractory to antitoxin treatment. In an FDA clinical surrogate model of lethal respiratory botulism in guinea pigs, treatment with Cyto-111 provided 55% survival. Currently, we are evaluating the safety and efficacy of Cyto-111 in a Rhesus macaque model of botulism. Conclusion(s): Collectively, these results demonstrate that Cyto-111 reverses clinical symptoms of botulism and prevents mortality following exposure to lethal doses of BoNT/A. Cyto-111 represents a first-in-class, novel therapeutic approach that allows the precise delivery of single-domain function-blocking antibodies to the presynaptic compartment of BoNT/A-intoxicated neurons. Disclaimer: The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army, Department of Defense, or the US Government. The experimental protocol was approved by the Animal Care and Use Committee at the United States Army Medical Research Institute of Chemical Defense, and all procedures were conducted in accordance with the principles stated in the Guide for the Care and Use of Laboratory Animals and the Animal Welfare Act of 1966 (P.L. 89-544), as amended. Funding(s): (1) Defense Threat Reduction Agency (DTRA), (2) NIH; R01-5R01AI093504, (3) ORISE, and (4) Geneva.

Technologies continue to shape the path of medical treatment. Orthopedic surgeons benefit from becoming more aware of how twenty-first century information technology (IT) can benefit patients. The percentage of orthopedic patients utilizing IT resources is increasing, and new IT tools are becoming utilized. These include disease-specific applications. This article highlights the opportunity for developing IT tools applicable to the growing population of patients with osteoarthritis (OA), and presents a potential solution that can facilitate the way OA education and treatment are delivered, and thereby maximize efficiency for the health care system, the physician, and the patient.

BACKGROUND/OBJECTIVE/OBJECTIVE:The objective of this study was to determine whether the extended or flexed knee positioning was superior for arthrocentesis and whether the flexed knee positioning could be improved by mechanical compression. METHODS:Fifty-five clinically effusive knees underwent arthrocentesis in a quality improvement intervention: 20 consecutive knees in the extended knee position using the superolateral approach, followed by 35 consecutive knees in the flexed knee position with and without an external compression brace placed on the suprapatellar bursa. Arthrocentesis success and fluid yield in milliliters were measured. RESULTS:Fluid yield for the extended knee was greater (191% greater) than the flexed knee (extended knee, 16.9 ± 15.7 mL; flexed knee, 5.8 ± 6.3 mL; P < 0.007). Successful diagnostic arthrocentesis (≥2 mL) was 95% (19/20) in the extended knee and 77% (27/35) in the flexed knee (P = 0.08). After mechanical compression was applied to the suprapatellar bursa and patellofemoral joint of the flexed knee, fluid yields were essentially identical (extended knee, 16.9 ± 15.7 mL; flexed knee, 16.7 ± 11.3 mL; P = 0.73), as were successful diagnostic arthrocentesis (≥2 mL) (extended knee 95% vs. flexed knee 100%, P = 0.12). CONCLUSIONS:The extended knee superolateral approach is superior to the flexed knee for conventional arthrocentesis; however, the extended knee positioning and flexed knee positioning have identical arthrocentesis success when mechanical compression is applied to the superior knee. This new flexed knee technique for arthrocentesis is a useful alternative for patients who are in wheelchairs, have flexion contractures, cannot be supine, or cannot otherwise extend their knee.

Background/Purpose: We hypothesized that mechanical compression of the knee in rheumatoid arthritis(RA) and osteoarthritis (OA) would mobilize occult extractable fluid and improve arthrocentesis success.
Method(s): 186 consecutive knees with gradeII-III OA and 67 knees with RA were included. Conventional arthrocentesis was performed and success and volume (milliliters) determined; the needle was left intra articularly, and mechanical compression was applied with an elastomeric knee brace. Arthrocentesis was then resumed until fluid return ceased. Fluid was characterized as to volume and cell counts.
Result(s): In the RA knee mechanical compression decreased failed diagnostic arthrocentesis from 56.7% (38/67) to26.9% (18/67) (-47.4%, p =0.003), and increased absolute arthrocentesis yieldfrom 4.7+/-10.3 ml to 9.8+/-9.8 ml (108% increase, 95% CI' -8.5 <-5.1< -1.7p=0.0038). Total extractable fluid yield was 96% greater in RA (9.8+/-9.8ml) than OA (5.0+/-9.4 ml, p = 0.0008), and occult extractable fluid was 77%greater in RA than OA (RA: 5.3+/-8.7 ml, OA 3.0+/-5.5 ml, p=0.046). Large effusions (>= 5 ml) in RA were associated with an increase in neutrophils in synovial fluid p=0.04) but not radiologic arthritis grade (p=0.87). In contrast, in the OA knee large effusions were associated with more severe arthritis grade(p=0.0001) but not synovial fluid neutrophil count (p=0.96).
Conclusion(s): Mechanical compression improves the success of diagnostic and therapeutic knee arthrocentesis in both RA and OA. Large effusions in RA are associated with inflammatory synovial fluid but not arthritis grade; in contrast, large effusions in OA are associated with more severe arthritis grades. (Figure Presented)