The present invention provides a deformable body (2), wherein the deformable body comprises a force application surface (12) opposite a bone contact surface (52) to be pressed against periosteum of a bone surface (52) of a bone such that the bone contact surface adapts its shape to the shape of the bone surface, wherein the deformable body comprises one or more through-going openings (3) and/or one or more fixation locations (34) arranged to receive a fixation element such as as screw (20), and wherein the deformable body comprises an anaesthetic that is released from or through the bone contact surface. The anaesthetic can be bupivicaine, liposome bupivacaine, lidocaine or levobupivacaine. The anaestethic can be arranged in one or more compartments (6, 7) which have ifferent release rates. The screw can comprise a detent or rim to mate with the deformable body. A sleeve (80) can be arranged in the opening (3) to receive the screw. A pusher element (81) can push the deformable body from the sleeve into position on the screw.