An impactor for positioning and holding a surgicalor veterinary prosthetic implant whilst it is being driven into position,said impactor including:- (a) an impaction means； (b) an impactionshoe which is configured to receive and support a prosthetic implantin a predetermined position； (c) connection means which connect theimpaction means to the impaction shoe and are configured to transmitan impact from the impaction means to the impaction shoe； (d) armsconfigured to engage an implant supported upon the impaction shoe；(e) said arms being biased into engagement with said implant, butmovable against the bias out of engagement with the implant； (f) saidconnection means being adjustable between a first setting at whichthe impaction shoe is spring-loaded so as to bias an implant supportedupon the impaction shoe into engagement with said arms but at whichthe impaction shoe can slide relative to said arms, against said springbias； and a second setting at which both the impaction shoe and thearms are rigidly engaged with an implant supported upon the impactionshoe, to hold the implant in a predetermined position and orientationrelative to the impaction means.
