BMJ - Hip Surgery Volume and Complications

"Relation between surgeon volume and risk of complications after total hip arthroplasty: propensity score matched cohort study"  
http://www.bmj.com/content/348/bmj.g3284 
"Conclusions In a cohort of first time recipients of total hip arthroplasty, patients whose operation was carried by surgeons who had performed 35 or fewer such procedures in the year before the index procedure were at increased risk for dislocation and early revision. Surgeons should consider performing 35 cases or more a year to minimize the risk for complications. Furthermore, the methods used to visualize the relationship between surgeon volume and the occurrence of complications can be easily applied in any jurisdiction, to help inform and optimize local healthcare delivery."