Surgical Considerations for Osteochondral Allograft Implantation
Precise fitting of the allograft and appropriate restoration of the articular anatomy are essential to long-term success.
By William D. Bugbee, MD; Andrea L. Pallante-Kichura, PhD; Simon Görtz, MD; Robert Sah, MD, ScD; and David Amiel, PhD
The operative procedure to implant osteochondral allografts demands precision to achieve reproducible results and minimize early graft failure related to surgical technique.
Precise fitting of the allograft and appropriate restoration of the articular anatomy are essential to long-term success. [7, 27-37] The surgical technique (Figure 1) for osteochondral allografting depends on the joint and surface to be grafted. Here, we highlight a few of the important considerations.
Figure 1. Surgical technique for osteochondral allograft transplantation.
In general, for femoral condyle lesions, a small arthrotomy is made to expose the cartilage defect and the lesion site is prepared. Then, a cylindrical plug or shell (free- hand) graft is harvested from the donor to match the defect. The donor OCA is carefully inserted (typically using short gentle impaction or manually pressed) until the cartilage is flush with the surrounding host cartilage.
Trochlea osteochondral allografts are more technically challenging, as the anatomy is complex and care must be taken to match the angle of approach.
For the patella, complete resurfacing can be performed in a manner similar to arthroplasty, whereas smaller lesions can be treated with dowel-type grafts (similar to femoral condyle lesions).
For tibial plateau osteochondral allografts, fluoroscopy is extensively used and the surgical technique is similar to unicompartmental arthroplasty; care must be taken to protect cruciate ligament and meniscal attachments, and the graft is typically thicker (minimum 10 mm) and fixed with interfragmentary screw fixation.
Relative contraindications include uncorrected ligamentous instability of the joint, or axial malalignment of the limb. These biomechanical parameters should be optimized prior to osteochondral allograft implantation, via ligament reconstruction or corrective osteotomy.
When an osteotomy is planned on the joint surface opposite the osteochondral allograft (ie, medial femoral condyle osteochondral allograft with tibial osteotomy), the procedures are performed concomitantly.
Conversely, if osteochondral allograft and osteotomy involve the same bone (commonly lateral femoral condyle osteochondral allograft with distal femoral osteotomy), then the procedures are staged to allow revascularization of the graft bed, with the osteotomy performed 6 months prior to osteochondral allograft.
The critical step in the procedure is to define the shape, size and exact location of the defect so that an exact orthotopic graft can be harvested from the donor. Donor and recipient are matched solely on the basis of size within 3 mm, determined using a mediolateral dimension of the tibia measured 0.5 cm below the joint surface.
In addition, the amount of allograft bone is typically limited to a few millimeters (3-4 mm), which is sufficient to provide stable fixation, but minimize the volume of transplanted bone. If bone involvement is extensive (>10 mm), autograft bone can be used to fill the defect. If the graft is large or is not circumferentially contained, additional fixation (absorbable pins) may be required.
William D. Bugbee, MD, is Adjunct Professor, Department of Orthopaedic Surgery, University of California, San Diego, and Attending Physician, Division of Orthopaedic Surgery, Scripps Clinic, La Jolla, California. Andrea L. Pallante-Kichura, PhD, is a medical writer, The Shiley Center for Orthopaedic Research and Education, Scripps Clinic, La Jolla, California. Simon Görtz, MD, is an orthopaedic surgery resident in the Department of Orthopaedic Surgery, University of California, San Diego. Robert Sah, MD, ScD is Professor, Departments of Bioengineering and Orthopaedic Surgery, University of California, San Diego, and Director of the Cartilage Tissue Engineering Laboratory. David Amiel, PhD, is Professor, Department of Orthopaedic Surgery, University of California, San Diego and director of the Connective Tissue Biochemistry Laboratory.
Excerpted with permission from Osteochondral Allograft Transplantation in Cartilage Repair: Graft Storage Paradigm, Translational Models, and Clinical Applications, by William D. Bugbee, MD; Andrea L. Pallante-Kichura, PhD; Simon Görtz, MD; Robert Sah, MD, ScD; and David Amiel, PhD; application for 2015 Kappa Delta Award, submitted June 2014.