What are the outcomes of core decompression in patients with avascular necrosis? Protocol for a systematic review

Background: Core decompression is a hip preserving surgical procedure that is used to treat avascular necrosis (AVN) of the femoral head. The eventual clinical and radiological outcome following this procedure is varied in literature. Also, the time to a total hip replacement (THR) from the index procedure and the percentage of patients subsequently undergoing a THR is controversial. Furthermore, there are multiple surgical methods along with multiple augmentation techniques and various classification and staging systems described. The purpose of this systematic review, therefore, is to analyse the outcomes following decompression only, excluding any augmentation techniques for non-traumatic AVN of the femoral head. Methods: This protocol is being developed in line with the PRISMA-P guidelines. The search strategy includes articles from Medline, Embase, Google Scholar, CINHAL and Cochrane library. The review and screening will be done by two independent reviewers. Review articles, editorials and correspondences will be excluded. Articles including patients with sickle cell disease and with core decompression where augmentation is used will be excluded. The risk of bias and quality of articles will be assessed using the Joanna Briggs Institute Critical Appraisal Checklist for the different study designs included. Discussion: This study will be a comprehensive review on all published articles having patients with AVN of the femoral head and undergoing core decompression surgery only. The systematic review will then define the outcomes of the core decompression surgery based on clinical and radiological outcomes. Each outcome will include the different stages within it and finally, the total mean time to THR will be calculated. This will then be followed by assessing the cumulative confidence in evidence from all the data collected using the GRADE tool. Registration: This systematic review is registered in the International Prospective Register for Systematic Reviews and Meta-analysis (PROSPERO) under the registration number: CRD42018100596