The evolution of progressive postoperative weight bearing after autologous chondrocyte implantation in the tibiofemoral joint.

Autologous chondrocyte implantation (ACI) has demonstrated good clinical success in the repair of articular cartilage defects in the knee. Postoperative rehabilitation after ACI is considered critical in returning the patient to an optimal level of function by attempting to create the appropriate mechanical environment for cartilage regrowth, and it involves a progressive program that emphasizes full motion, progressive partial weight bearing (PWB), and controlled exercises. While evidence-based research is clearly lacking in all components of ACI rehabilitation, one important element in this treatment algorithm that has been subjected to some early scientific study is the gradual progression of the patient back to full weight-bearing (WB) gait after surgery. With the continual advancement of ACI surgical techniques, along with clinical experience and improved knowledge of histology and of the maturation process of chondrocytes, proposed postoperative WB protocols have evolved to better reflect the nature of the specific ACI surgery. The purpose of this article is to present the varied PWB programs that have been practiced alongside the evolving ACI surgical technique, the experimental basis for such protocols, the issues pertinent to the accurate prescription of WB, and future directions for developing such methods to best return patients to an optimal level of function after ACI.