Ultrasound measurement of knee synovial fluid during external pneumatic compression

Abstract

Synovial fluid based biomarker research has been limited by the small volumes of synovial fluid from the knees of some patients. We used ultrasound (US) to determine if synovial fluid could be displaced into an access port during pneumatic compression to 100 mmHg. Forty knees from 37 consecutive arthritis patients with rheumatoid arthritis −25, osteoarthritis −8, psoriatic arthritis −2, and 1 each with systemic lupus erythematosus and gout were evaluated. This group of 28 females and 9 males with a median age of 59 years and an average body mass index of 26.9 kg/m2 had previously undergone a diagnostic arthrocentesis and or a therapeutic knee injection using this pneumatic compression device. Blinded digital image analysis of the anechoic region on ultrasound demonstrated an increase in fluid within the 9 cm × 6 cm access port (anterolateral or anteromedial joint) during inflation in all patients with a 2.5–3.5 fold increase in fluid area and a 2–3 fold increase in fluid depth after inflation, p < 0.001. Statement of clinical significance: External pneumatic compression to the knee provides a larger volume of synovial fluid under positive pressure which should allow investigators to achieve greater success in obtaining synovial fluid during arthrocentesis for biomarker research or provide more precise therapeutic injections than traditional non image‐guided anatomical landmark‐based techniques. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res

Extraction of Synovial Fluid from the Non-Effusive Pathologic Knee with Pneumatic Compression

“…Subsequently, the superior knee and suprapatellar bursa were compressed with a pneumatic blood pressure cuff to 100 mg Hg, arthrocentesis was again attempted with marked improved arthrocentesis success. Unlike previous reports that used a specialty compression cuff, the present study demonstrates that a widely available, inexpensive conventional thigh blood pressure cuff can be used to provide circumferential pressure to effectively extract fluid from the non-effusive knee [12,20,21,26,27].…”

“…Extraction of synovial fluid for crystal examination and cellular, immunologic, biomarker and metabolic analysis is presently an important area of clinical care and research integral to current and future joint preservation strategies and therapies [1][2][3][4][5][6][7][8][9][10]12,[22][23][24][25]. Thus, obtaining at least a minimal volume of synovial fluid from a painful or pathologic knee is important diagnostically, prognostically, for accurate injection of therapeutics, and scientifically, especially for research and development of precision arthritis therapies [20][21][22][23][24][25][26][27] In the current study we report significant improvement in terms of arthrocentesis fluid yield and diagnostic success from pneumatic compression of the non-effusive knee (Table 1, Figure 5). Using the flexed knee positioning, 111 consecutive clinically non-effusive OA knees underwent arthrocentesis using a standard anterolateral portal.…”

“…For the diagnosis of crystal disease often only a few drops of synovial fluid are required; however, special analyses may require 0.1 ml or more and conventional analysis usually requires at least 2 ml . To obtain adequate synovial fluid yield from the non-effusive knee, ultrasound guidance, stress maneuvers, joint lavage, and external compression may be used to obtain adequate synovial fluid volumes [12,[20][21][22][23][24][25][26][27][28][29].…”

Synovial Fluid Cytokines, Chemokines and MMP Levels in Osteoarthritis Patients with Knee Pain Display a Profile Similar to Many Rheumatoid Arthritis Patients

“…To facilitate SF removal, knee aspirations were obtained in all but 3 subjects using an external pneumatic compression device (KneeTap TM , Arthroventions LLC Denver CO) inflated to 100 mmHg as previously described [ 17 ]. One patient had an excessive thigh girth and 2 RA patients had very large effusions.…”

Precision Medicine for Rheumatoid Arthritis: The Right Drug for the Right Patient—Companion Diagnostics

“…Published studies indicate that in the absence of image guidance physicians may actually miss the intra-articular knee space for injections by up to 25% of attempts [43]. However, ultrasound localization of SF and other technologies may allow easier sampling of SF in the future [44][45][46].…”