Effective treatment of knee extensor mechanism disruptions requires prompt diagnosis and thoughtful decision-making with surgical and nonsurgical approaches. When surgery is chosen, excellent surgical technique can result in excellent outcomes. Complications and failures arise from missed or delayed diagnoses and from technical problems in the operating room. In particular, inappropriate surgical timing (especially late surgery), misplaced patellar drill holes, and failure to address concomitant injuries can result in complications seen when repairing a patellar or quadriceps tendon tear. We review the complications that can occur during treatment of these injuries (Table 1).