Painful Total Hip Arthroplasty: A Systematic Review and Proposal for an Algorithmic Management Approach.

BACKGROUND:The etiological diagnosis of painful primary total hip arthroplasty and its management is a complex clinical challenge for pain physicians. Extrinsic sources of pain in the hip joint might be efficiently treated by clinical pain units, although the topic remains controversial. OBJECTIVES:To conduct a literature review and suggest an evidence-based algorithmic approach to managing painful hip arthroplasty. STUDY DESIGN:Systematic literature review with qualitative data synthesis. METHODS:We conducted an online search of Medline/Pubmed, Embase, Clinical Trials, and Cochrane database using the Medical Subject Heading (MeSH) and free terms on all biomedical literature published up to August 2019. Articles that described either the etiologies and management of painful primary total hip arthroplasty or the imaging techniques to specifically assess any of its causes were included. We collected the demographic data (gender, age, body mass index), main etiologies, diagnostic tests, and specific treatments applied in each study. Based on the reviewed evidence, we propose an algorithmic approach, with a special emphasis on etiologies that should be referred to pain clinics. RESULTS:Twenty-four studies were included for the synthesis, 16 of which were observational studies and 8 of which were non-systematic literature reviews that described a wide range of etiologies of painful primary total hip arthroplasty. The results showed that 2/3 of the causes of pain were intrinsic and need to be managed by orthopedic surgeons. One third of the etiologies were extrinsic and should be referred to pain clinics once intrinsic causes have been ruled out. Among extrinsic sources of pain, the most frequent was myofascial etiology. LIMITATIONS:A publication bias might have been present due to the inclusion of studies published only in English, Spanish, and German. The included studies also had heterogeneous methodologies. CONCLUSIONS:The current review suggests that painful hip arthroplasty is not a rare condition in clinical practice. We systematically reviewed etiologies and various treatments published in the literature and we suggest an algorithmic approach to management based on the available evidence. This approach incorporates the evidence regarding our knowledge of the etiologies, diagnosis, and management of chronic pain after total hip arthroplasty. Systematic review registration: The protocol was registered in PROSPERO the international prospective register of systematic reviews, ID CRD42020185663.