Table 4.

Sample size calculations comparing total hip arthroplasty (THA) and hemiarthroplasty (HA)

HA 1 year event risk	Total patients required	Expected events (n)	RRR
4%	1123	72	0.50
5%	1316	96	0.45
6%	1435	108	0.42

Sample size requirement for HEALTH Pivotal Trial (non-inferiority design).

RRR, relative risk reduction.