Table 3.

Incidence of periprosthetic infections at 90 d following total hip arthroplasty

Location	Spring	Summer	Fall	Winter	χ2
North East	0.82%	0.83%	0.84%	0.91%	0.358
Mid West	0.97%	0.97%	0.88%	1.04%	0.013
South	1.06%	1.06%	0.96%	1.10%	0.007
West	0.84%	0.84%	0.88%	0.89%	0.68
Mean	0.92%	0.92%	0.89%	0.98%
SD	0.11%	0.11%	0.05%	0.10%