The extended knee superolateral approach for arthrocentesis is clearly superior to the conventional flexed knee anterolateral approach, and thus, this study confirms and supports the extended knee positioning for conventional arthrocentesis. However, when constant mechanical compression is applied with an external compression brace to the suprapatellar bursa and patellofemoral joint of the flexed knee to displace fluid from the superior knee to the inferior knee where it can be accessed, the extended knee superolateral approach and the flexed knee anterolateral approach for arthrocentesis have identical arthrocentesis success and fluid yields. For the elderly, individuals with knee contractures, the obese, wheelchair-bound individuals, or those apprehensive individuals who involuntarily and forcefully contract the quadriceps muscles during a procedure, the standard extended knee superolateral approaches for arthrocentesis may be difficult and/or inconvenient. Thus, a method of aspirating the flexed knee that permits the patient to remain in the sitting position with a bent knee and does not require forcing the needle into the constrained anatomy of the patellofemoral joint, but provides similar levels of arthrocentesis success and yield, will be of obvious clinical utility in these selected clinical situations.
The authors thank Jackie Cremar for logistic assistance in preparation of this article. They also thank the staff of their local institutional review board (the Human Research Committee) for guiding them in the preparation of this study, data, and article.
J Clin Rheumatol. 2018;24(6):295-301. © 2018 Lippincott Williams & Wilkins