Patent ID: 8277460

Claim:
An impactor for positioning and holding a surgical or veterinary prosthetic implant while it is being driven into position, said impactor including: (a) an impaction means; (b) an impaction shoe which is configured to receive and support a prosthetic implant in a predetermined position; (c) connection means which connect the impaction means to the impaction shoe and are configured to transmit an impact from the impaction means to the impaction shoe; (d) arms configured to engage an implant supported upon the impaction shoe; (e) each of said arms being spring biased by a first biasing means into engagement with said implant, wherein each of said arms is movable against the bias of said first biasing means out of engagement with the implant; (f) said connection means being adjustable between a first setting at which the impaction shoe is spring-loaded by a second biasing means so as to spring bias an implant supported upon the impaction shoe into engagement with said arms but at which the impaction shoe can slide relative to said arms, against said spring bias of said second biasing means; and a second setting at which both the impaction shoe and the arms are rigidly engaged with an implant supported upon the impaction shoe, to hold the implant in a predetermined position and orientation relative to the impaction means; (g) wherein the connection means includes an impactor plate which is rigidly connected to one end of a shaft, the other end of which is configured to be in load transmitting engagement with the impaction shoe when said connection means is at said second setting; (h) wherein a portion of said shaft is externally screw threaded and is in screw threaded engagement with a housing which is slidably engaged with the impaction shoe; said second biasing means comprising a spring mounted between the impaction shoe and the housing, said spring being configured to bias the impaction shoe away from the housing; (i) said shaft and said housing being configured such that when said connection means is at said first setting said screw threaded portion of said shaft is only partially engaged with the housing and when said connection means is at said second setting, said screw threaded portion of said shaft is fully engaged with the housing and said other end of said shaft is in load transmitting engagement with the impaction shoe.