Patellofemoral instability (PFI) is a common clinical problem encountered by orthopedic surgeons specializing in the knee. Patellofemoral instability surgery have been shown to achieve satisfactory clinical outcomes through reducing patella dislocations, improving function, and returning to pre-injury levels of activity. However, complications and failures from surgery can be high. Foreseeably, an increasing number of revision PFI surgeries will be seen in upcoming years. There are numerous factors which contribute to stability of the patellofemoral (PF) joint and thorough clinical assessment and appropriate radiological investigations are essential in determining which risk factors need to be corrected to prevent failures in PF instability surgery. These complications can be largely split into two groups; complications resulting from not tailoring the operation to the patient`s individual risk factors and complications resulting from technical error. Patientspecific surgery in PFI is an important area with growing evidence. Studies have highlighted that failures of MPFL reconstruction can be high in the presence of significant trochlear dysplasia and high tibial tubercle-trochlear groove distances. Failure to address these bony factors can lead to poor outcomes and complications. It is, therefore, crucial to address significant bony abnormalities. The key bony factors to consider are increased valgus, patella alta, trochlear dysplasia, or rotational problems. This article will outline the approach to assess a patient presenting with failure of PFI surgery.