Elution of proteins by continuous temporomandibular joint arthrocentesis

Purpose: The purpose of this study was to determine whether specific proteins recovered from human temporomandibular joints (TMJs) by superior space arthrocentesis are eluted at different outflow volumes. Materials and Methods: Twenty subjects with unilateral TMJ pain and restricted mandibular range of motion underwent superior space arthrocentesis of the affected TMJ. Sixteen serial fractions of the arthrocentesis outflow volume were collected for analysis. The protein content of each fraction was determined by a BCA protein assay and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). In addition, samples from each collected fraction were assayed for protease activity. Results: The average amount of protein recovered in the total 32 mL of collected arthrocentesis fluid was 1.5 mg (0.72 to 2.1 mg). Significant differences (P = .03) in total protein recovered from arthrocentesis fluid were observed between males (0.824 +/- 0.43 mg/20 mL) and females (1.389 +/- 0.54 mg/20 mL). In general, protein concentration declined serially in collected TMJ lavage fluid fractions. Specific proteins and proteases detected in the lavage fluid were eluted at different outflow volumes. Conclusions: Although specific proteins are eluted from the TMJ at different outflow volumes during arthrocentesis, the procedure effectively reduces the protein concentration of the lavage fluid in a volume-dependent manner. Based on empirical assumptions, it is estimated that approximately 100 mL of total arthrocentesis volume is sufficient for a therapeutic lavage of the superior joint space of the human TMJ.