Pelvic Malunion: A Systematic Review, Dichotomy of Definitions and Treatment

Background and Objectives: Pelvic nonunion and malunion have been documented as rare complications in pelvic fractures and literature describing these topics is severely limited. Articles dedicated solely to pelvic malunion are nearly nonexistent. We conducted a literature search with the goal of providing a summary of the definition, causes, treatment strategies, and outcomes of pelvic malunion correction. Materials and Methods: An initial review of the literature was performed using the PubMed, ScienceDirect, and Cochrane Database of Systematic Reviews databases. Search terms used were "malunion" AND "pelvic" OR "pelvis". Duplicate articles, non-English language articles without translations available and non-human subject studies were excluded. Results: Eleven original publications were found describing experiences with pelvic malunion. Seven of the articles were exclusively dedicated to the topic of pelvic fracture malunion, and only two reported on a series of patients treated for malunion with variably staged procedures. Most reports define pelvic pain as the main indication for surgical correction, along with gait disturbance, standing or sitting imbalance, and urinary or sexual dysfunction. Radiographically, vertical displacement of one to two centimeters and rotation of the hemipelvis of fifteen degrees or more have been described in defining malunion. No treatment algorithms exist, and each patient is treated with a unique work-up and operative plan due to the complexity of the problem. Only one series reported a patient satisfaction rate of 75% following malunion treatment. Conclusions: Pelvic malunion is a rare complication of pelvic ring injury and is seldom discussed in the literature. We found two small case series reporting exclusively on malunion treatment and complications. While some of the combination studies made the distinction in the diagnosis of malunion and nonunion, they rarely differentiated the treatment outcomes between the two categories. This paper describes pelvic malunion and highlights the need for more research into surgical outcomes of treatment specifically regarding functionality, patient satisfaction, and recurrence of preoperative symptoms.