Review Question - QID 372

Joint space narrowing on a merchant view is a contraindication for autologous chondrocyte implantation for patellofemoral arthritis.

Saleh et al states ACI relies on intact, full-thickness cartilage margins to maintain the joint space so that the growing cartilage repair tissue may fill the defect. Cartilage loss seen with diffuse arthritis is not amenable to ACI. It is critical that there is a preserved patellofemoral joint space as seen on a Merchant or skyline view. The article states that ACI can be used for grade 3 or 4 defects on the patella or trochlea. Concomitant realigment procedures of the patellofemoral joint (such as lateral release, medial tubercle transfer, or anteromedial tubercle transfer) and the tibiofemoral joint (high tibial osteotomy) are indicated in the presence of mechanical malalignment.

The article by Peterson et al followed 94 patients for 2-9 years and found graft failure in only seven patients. Histologic analysis of 37 "second-look" arthroscopy biopsy specimens showed a correlation between hyaline-like tissue and good to excellent clinical results.

NOTICE: ACI is not FDA approved for use on the patella and the use of ACI "off-label" should be discussed with patients preoperatively.