Table 3.

Study characteristics and study methodology.

	Hip stems	Hip cups	Knees	All
Number of articles	63	34	54	151
Publication period	1995–2021	2007–2021	2002–2021	1995–2021
Location (%)
Europe	66.7	70.6	61.1	63.6
Americas	23.8	0	29.6	19.9
Asia	1.6	23.5	9.3	9.3
Other	7.9	11.8	1.9	5.3
Study type
Case report	3.2%	11.8%	1.9%	4.6%
Case–control	–	–	5.6%	2%
Cohort registry based	7.9%	11.8%	18.5%	12.6%
Other cohorts	84.1%	67.6%	59.3%	71.5%
Retrospective*	83.0%	56.5%	62.5%	72.2%
RCT	4.8%	8.8%	14.8%	9.3%
Comparator group(s), yes	41.3%	23.5%	59.3%	43.7%
Adjusted† analysis, yes	25.4%	5.9%	38.9%	25.8%
Number of prostheses included
Mean	615	613	1460	917
Median (range)	139 (1–14’147)	95 (1–14’147)	180 (1–27’193)	139 (1–27’193)
Median inclusion period (years)	3	2	3	3
Follow-up‡ (years)	5.5 (0.1–17.8)	5.0 (0.3–15.0)	3.4 (1–13.4)	4.6 (0.1–17.8)
First inclusion date to publication in years‡	10 (4–22)	9 (2–21)	11 (3–20)	10 (2–22)
FDA approval to first publication in years‡	5 ((–8)–10)	2 (1–3)	5 ((–3)–8)	5 ((–8)–10)
CE-mark date to first publication in years‡	9 (3–13)	10 (7–12)	7 (5–10)	9 (3–13)

^*Percentage of other cohorts; ^†matching instead of adjustment was used in 1 study; ^‡values are median (range).