Abstract: An arthroscopic surgery device for delivering a therapeutic formulation into a cartilage of an articular joint, wherein the device comprises: a flexible tubular delivery arm, comprising one or more internal channels for carrying the therapeutic formulation; a flexible external sleeve enveloping the delivery arm lengthwise; a pliable cup attached to an end of the delivery arm, for covering a cartilage part where the therapeutic formulation is to be delivered, arranged such that by outwards axial displacement of the delivery arm in respect to the external sleeve, the cup moves from inside to outside of the external sleeve, expanding the cup. The device may comprise a flexible internal sleeve between the delivery arm and the external sleeve, such that the flexible internal sleeve envelops the delivery arm lengthwise. The arthroscopic surgery device may be also used for extracting fluid from an articular cavity.