Proximal junctional kyphosis: What we didn't know, what we think we know, and what we need to know

Proximal junctional kyphosis (PJK) is a common post-operative phenomenon among patients with adult spinal deformity. In a subset of cases, PJK can progress to proximal junctional failure (PJF) which is PJK with structural failure and usually requires revision surgery. Many patient and surgical risk factors for PJK have been identified in an attempt to predict and prevent the development of PJF. In this paper, we summarize the existing literature regarding the risk factors for and treatment of PJK and PJF. We further provide evidence guided treatment recommendations for surgeons managing spinal deformity patients.