TABLE IV.

High-Risk Pedigrees Demonstrating Excess Clustering of Periprosthetic Joint Infection

		Periprosthetic Joint Infection			Total Joint Arthroplasty
Founder*	Descendants	Familial Standardized Incidence Ratio	P Value	Observed	Familial Standardized Incidence Ratio	P Value	Observed	Ratio‡
1†	5,876	7.05	0.0001	7	1.22	0.0874	54	0.13
2	2,999	9.82	0.0002	5	1.27	0.1175	29	0.17
3	2,675	10.51	0.0001	5	1.51	0.0179	31	0.16
4	3,672	9.29	0.0002	5	1.58	0.0059	37	0.14
5	3,747	9.08	0.0003	5	1.58	0.0053	38	0.13
6	4,591	7.41	0.0007	5	1.32	0.0535	39	0.13
7	6,468	5.55	0.0009	6	1.31	0.0246	62	0.10
8	7,060	4.26	0.0071	5	1.05	0.3836	54	0.09
9	8,302	4.67	0.0021	6	1.14	0.1686	65	0.09

^*A founder is the ancestor from whom all family members are descended.

^†This founder is shown in Figure 3.

^‡This ratio is periprosthetic joint infections per total joint arthroplasty.