A kit of parts for inserting a deformable implant into a cavity in a bone of a patient is described. An inserter instrument (1) comprises a body (100) having a cavity extending along a longitudinal axis from a distal end to a proximal end. An attachment mechanism (108) is provided at the distal end and to which a deformable implant can be releasably attached. A drive mechanism (132) is provided at the proximal end of the body. A push rod (150) is freely and slidably arranged within the cavity and has a distal end engageable with a part of the deformable implant and a proximal end abutable by the drive mechanism. The drive mechanism is operable to drive the push rod toward the distal end of the body. The kit also includes an impactor (210) dimensioned for slidable engagement within the cavity.
