The “true” incidence of surgically treated deep prosthetic joint infection after 32,896 primary total hip arthroplasties

Figures & data

Figure 1. Revisions identified in either the DHR or the NRP.

Figure 2. Algorithm for classification of the1,522 first-time revisions performed because of deep infection or other causes.

Figure 3. Algorithm (continued) for classification of the revisions performed due to periprosthetic joint infection or other causes.

Table 1. Cumulative incidence of revision for any reason following total hip arthroplasty (THA)

Register	No. of primary THAs	No. of revisions	Cumulative incidence (%) (95% CI)
1 year
DHR	32,896	730	2.22 (2.06–2.38)
NRP	32,896	839	2.55 (2.39–2.73)
Combined	32,896	930	2.83 (2.65–3.01)
2 years
DHR	27,906	802	2.87 (2.68–3.08)
NRP	27,906	893	3.20 (3.00–3.41)
Combined	27,906	990	3.55 (3.34–3.77)
5 years
DHR	13,175	560	4.25 (3.92–4.60)
NRP	13,175	589	4.54 (4.19–4.90)
Combined	13,175	662	5.02 (4.66–5.41)

DHR: the Danish Hip Arthroplasty Register;

NRP: the National Register of Patients.

Table 2. Cumulative incidence of prosthetic joint infection following primary total hip arthroplasty (THA)

Register	No. of primary THAs	No. of revisions	Cumulative incidence (%) (95% CI)
1 year
DHR	32,896	167	0.51 (0.44–0.59)
NRP	32,896	158	0.48 (0.41–0.56)
Algorithm	32,893	285	0.86 (0.77–0.97)
2 years
DHR	27,906	185	0.61 (0.52–0.70)
NRP	27,906	150	0.54 (0.46–0.63)
Algorithm	27,903	266	0.96 (0.85–1.08)
5 years
DHR	13,175	84	0.64 (0.51–0.79)
NRP	13,175	75	0.57 (0.45–0.71)
Algorithm	13,172	136	1.03 (0.87–1.22)

DHR: the Danish Hip Arthroplasty Register;

NRP: the National Register of Patients.

Figure 4. Prosthetic joint infections over 1 year, with 95% CI.