Table 2.

Pearls, Pitfalls, and Risks

Pearls: • Donors must be under 45 yr old • Allograft sizing is performed in accordance with a preoperative CT scan (made both in the patient and on the graft), anthropometric agreement between donor and recipient, and Wiberg's classification for the shape of the patella • Ideally, 2 surgical teams work in parallel to optimize operating times • In the scenario of concomitant large trochlear cartilage injuries, a combined transplant of the patellar and trochlear surface can be a valid option • Care should be taken to position the cutting guide to eliminate only 6 to 8 mm of the subchondral bone tissue. This step is of utmost importance because the thicker the bone tissue, the higher the possibility of an immune reaction or bone resorption • To further diminish the graft immunogenicity, remove all the remaining soft tissues and use high-pressure pulsatile lavage irrigation • With a sterile skin marker, draw points at the proximal and lateral part of the graft to help in its orientation when placement in the recipient area is performed • The authors suggest using 1.5-mm absorbable pins positioned anterogradely because graft thickness is limited and fixation from the dorsal aspect of the patella with metal screws could be difficult • Circumferential denervation of the patella further helps in preventing residual anterior knee pain

Pitfalls and Risks: • Because it only allows storage for limited time before transplantation, hospital activity as well as surgeon and patient availability may make to cancel the procedure • Unaddressed patellofemoral instability may lead to failure • If the graft should fall on the floor, by any chance, we recommend a new washing process with the high-pressure pulsate irrigation system for no less than 20 min with subsequent immersion in a 1 g/100 mL vancomycin solution for 10 min • There is a potential risk for transmission of infectious diseases • Potentially, the procedure can lead to some degree of immunoreaction

CT, computed tomography.