Table 1.

Pearls and Pitfalls

Pearls

Pitfalls

1.Size-matching the patella allograft can optimize patellar tracking 2.Obtain preoperative CT and MRI scans to assess for trochlear dysplasia and/or osteochondral defects 3.Obtain preoperative fluoroscopic images of the normal, contralateral knee to assess baseline CDI 4.Before TTO, measure the allograft tibial tubercle according to length, width, and depth 5.Following patellectomy and before TTO, lay down the allograft over the affected knee and obtain fluoroscopic images to ensure proper patellar height as compared to the contralateral extremity 6.Preserve as much native quadriceps tendon as possible as a Pulvertaft weave of the allograft quadriceps tendon can improve graft incorporation 7.When placing sutures in the native quadriceps tendon, avoid placing Krackow sutures centrally as the allograft will be woven through the native tendon in this area

1.Use of a nonfresh, non-size-matched allograft could result in graft failure and/or patellar maltracking with pain 2.Failure to match or approximate the contralateral knee CDI can result in pain and/or patellar maltracking 3.Incorrectly sizing the tibial tubercle allograft bone block can put excess pressure on the skin and affect cosmesis 4.Failure to immobilize for 12 weeks in knee extension can result in tibial tubercle fracture and nonunion

CDI, Caton Deschamps Index; CT, computed tomography; MRI, magnetic resonance imaging; TTO, tibial tubercle osteotomy.