Table 1

Characteristics of data in the non-registry periods

	Period reported	Reported data	Other details	Source
Included reports
New Zealand	1980–1991	Hip	Preregistry data	34
Iceland	1982–1996	Hip	Country without joint registry	35
USA	1990–2002	Hip and knee	Preregistry data	36
USA	2005–2011	Hip and knee	Preregistry data	21
England/Wales	1991–2000	Hip and knee	Preregistry data	12
Italy	2001–2005	Hip and knee	Preregistry data	13
Spain	1997–2011	Knee	Country without joint registry	11
Taiwan	1998–2009	Hip and knee	Country without joint registry	37