BackgroundLack of evidence contributes to unnecessary variation in treatment costs and outcomes. This study aimed to identify from interventions historically used for total knee or hip arthroplasty (TKA, THA): i) if routine use is supported by high-level evidence; ii) whether surgeon use aligns with the evidence.MethodsPart 1: Systematic search of electronic library databases for systematic reviews and practice guidelines concerning seven acute-care interventions. Intervention-specific recommendations concerning routine use were extracted by assessors. Part 2: Prospective medical record audit of the acute-care received by 1900 patients involving 120 orthopaedic surgeons. Surgeon use per intervention was summarized using caterpillar plots. Surgeon-specific routine and non-routine use was defined as use in ≥ 90% and ≤ 10% of patients, respectively. Primary analysis included only surgeons contributing ≥ 10 patients.ResultsContinuous passive motion (TKA): Routine use not recommended; 85.7% of surgeons did not use it routinely. Tranexamic Acid: Routine use recommended; 26.9% of surgeons used it routinely. Cryotherapy: Routine use not recommended; 45.7% of surgeons used it routinely for TKA; 31.8% used it routinely for THA. Intra-articular drainage: Routine use not recommended for TKA, but possible benefits for THA; 5.7% of surgeons used it routinely for TKA, 0.0% used it routinely for THA. Antibiotic loaded bone cement: Routine use for TKA not supported, recommendations for use for THA are inconsistent; 90.0% of surgeons used it routinely for TKA, 100.0% used it routinely for THA. Patella resurfacing (TKA): No recommendation could be made; 57.1% of surgeons routinely resurfaced the patella. Indwelling urinary catheterisation: Routine use recommended; 59.6% of surgeons used it routinely.ConclusionRecommendations for routine use or not exist for some of the acute-care interventions examined. Surgeon practices vary widely even in the presence of high-level recommendations. It is unclear whether further evidence alone would lessen unwarranted practice variation.