'The Implantation Contract. On the Warranty Liability of the Treating Party under Sales Law for Defective Implants': If a defective implant (e.g. pacemaker) has been inserted in a patient, the costs of replacement (new implant and revision surgery) are by now usually borne by the health insurance companies. This ignores the fact that the implantation contract is not merely a treatment contract but also contains an element of sales law. Patients or their (statutory) health insurance companies therefore have a claim of redress by repair or replacement against the hospital acting as the ¿seller¿ of the implant.