Table 2.

Arthroscopic EWAS (European Wrist Arthroscopy Society) Classification

Arthroscopic stage (EWAS)	Arthroscopic testing of SLIOL from MC joint
I	No passage of the probe in SL space but synovitis
II	Lesion of membranous SLIOL Passage of the tip of the probe in the SL space without widening (stable)
III A	Partial lesion involving the volar SLIOL Volar widening on dynamic testing from MC joint (anterior laxity)
III B	Partial lesion involving the dorsal SLIOL Dorsal SL widening on dynamic testing (posterior laxity)
III C	Complete SLIOL tear, joint is reducible Complete widening of SL space on dynamic testing, reducible with removal of probes
IV	Complete SLIOL with SL gap SL gap with passage of the arthroscope from MC to RC joint No radiographic abnormalities
V	Wide SL gap with passage of the arthroscope through SL joint Frequent X-ray abnormalities such as an increased SL gap, DISI deformity

SLIOL scapholunate interosseous ligament, MC midcarpal, RC radiocarpal, RSC radio-scapho-capitate, LRL long radiolunate, DIC dorsal intercarpal ligament, SL scapholunate, TH triquetro-hamate, ST scaphotrapezial, DRC dorsal radiocarpal, DISI dorsal intercalated segmental instability