Patent ID: 8419763

Claim:
A method for accessing the interior of a hip joint, the method comprising: providing a safety needle comprising: a handle; a hollow needle fixedly mounted to the handle, the hollow needle having a sharp distal end; a trigger carriage slidably mounted to the handle for movement between a distal position and a proximal position; an obturator mounted to the trigger carriage and slidably received within the hollow needle, the obturator having a distal end wherein the distal end of the obturator is closed off by an end wall, and the obturator being sized such that (i) when the trigger carriage is in the distal position, the distal end of the obturator extends beyond the sharp distal end of the needle, and (ii) when the trigger carriage is in the proximal position, the distal end of the obturator is received within the sharp distal end of the needle; a spring for urging the trigger carriage into the distal position; a trigger mounted to the trigger carriage for urging the trigger carriage towards the proximal position when operated; a first latch for releasably locking the trigger carriage in the distal position when the first latch is set, the latch configured to be set or released by operation of the trigger; a second latch for releasably locking the trigger carriage in an intermediate position located between the distal position and the proximal position, wherein the distal end of the obturator partially emerges from the hollow needle when the trigger carriage is in the intermediate position, the second latch configured to be set or released by operation of the trigger; the first latch, the second latch, and the trigger being configured so that when the trigger carriage is in its distal position and the first latch is set, and the trigger is thereafter pulled proximally, the first latch is released and the trigger carriage moves proximally into its proximal position, and thereafter releasing the trigger causes the trigger carriage to move into the intermediate position and set the second latch; and further wherein, when the trigger carriage is in its intermediate position and the distal end of the obturator engages tissue surrounding the hip joint, the trigger carriage is moved proximally so as to release the second latch; configuring the safety needle so that the trigger carriage is in the distal position and the first latch is set by operation of the trigger; moving the trigger so that the first latch is released and the trigger carriage moves proximally into the proximal position; releasing the trigger so as to cause the trigger carriage to move into the intermediate position and set the second latch; and advancing the safety needle so that the sharp distal end of the needle and the distal end of the obturator engage tissue surrounding the hip joint.