EXPERIMENTAL STUDY A novel implantation technique for engineered osteo-chondral grafts C. Candrian Æ Andrea Barbero Æ E. Bonacina Æ S. Francioli Æ M. T. Hirschmann Æ S. Milz Æ V. Valderrabano Æ M. Heberer Æ I. Martin Æ M. Jakob Received: 12 November 2008 / Accepted: 18 February 2009 / Published online: 21 March 2009 Ó Springer-Verlag 2009 Abstract We present a novel method to support precise insertion ofengineered osteochondral grafts by pulling from the bone layer, therebyminimizingiatrogenic damage associated with direct manipulation of the carti- lage layer.Graftswere generated by culturing human expanded chondrocytes on Hyaff Ò -11 meshes, sutured to Tutobone Ò spongiosa cylinders. Through the bone layer, shaped to imitate the surface-contours of the talar dome, two sutureswere applied:the first for anterograde implantation, to pull the graftinto the defect, and the second forretrograde correction, in case ofa too deep insertion.All graftscould be correctly positioned into osteochondral lesionscreated in cadaveric ankle joints with goodfit to the surroundingcartilage.Implants withstood short-term dynamic stability tests applied to the ankle joint, withoutdelamination or macroscopic damage. The developed technique, by allowing precise and stable positioning of osteochondral graftswithout iatrogenic cartilage damage, is essential for the implan- tation of engineered tissues, where the cartilage layer is not fully mechanically developed, and could be consi- dered also for conventional autologousosteochondral transplantation. Keywords Tissue engineering Osteochondral lesion Ankle joint Osteochondral transplantation Introduction Osteochondral lesions(OCL) of the anklejoint (i.e., defects which affect both the articular cartilage and the underlying subchondral bone)are typically caused by traumatic injuries, chronic ankle instability, malalignment or avascular necrosis [18, 19]. In orderto preventhe onsetof premature osteoarthritic changes of the ankle joint [2, 3, 16, 20], the treatment of symptomatic OCL of the talus has been approached using a variety of surgical options,such as microfracturing, autologouschondro- cytestransplantation [6] or autologousosteochondral transplantation [8]. Despitethe encouraging reported clinicalresults in the clinical routine use of autologous osteochondral grafts [8, 22], the technique (often referred to as ‘mosaicplasty’) still suffers from several problems such asthe limited availability of grafts,the frequent donor site morbidity in up to 70% of patients [ 7, 22], and the difficulty to match the size and shape of the graft with the defect. Moreover, it was reported that the commer- cially available extraction and implantation instruments, based on press-fit techniques and pushing of the graft with a probe into the defect zone, can lead to cell death in the cartilage layer of the native autologous osteochondral graft [9, 15]. C. Candrian A.Barbero S.Francioli V.Valderrabano M. Heberer I.Martin (&) M. Jakob Departments of Surgery and Biomedicine, Institute for Surgical Research & Hospital Management, University Hospital Basel, Hebelstrasse 20, ZLF, Room 405, 4031 Basel, Switzerland e-mail: imartin@uhbs.ch A. Barbero e-mail: abarbero@uhbs.ch C. Candrian M.T. Hirschmann Department of Orthopaedic Surgery and Traumatology, Kantonsspital, Bruderholz, Switzerland E. Bonacina I.R.C.C.S Istituto Ortopedico Galeazzi, Milan,Italy S. Milz AO Research Institute, Davos,Switzerland 123 Knee Surg Sports Traumatol Arthrosc (2009) 17:1377–1383 DOI 10.1007/s00167-009-0766-4