Minimum dataset

Probably the most essential data item is the (new) National Health Service (NHS) number. This number is unique to each individual and should allow patients to be followed from birth to death. A number of audits in Scandinavia has been very successful at tracking patients over long periods and long distances because of the Swedish equivalent of the new NHS number. Outcome data on hip fractures and lower limb joint arthroplasty are examples of the type of long-term data collection that has occurred in Sweden (Thorngren, 1993).