Table 1.

Characteristics of patients undergoing primary total ankle arthroplasty

	All patients	Study time-periods						Comparison of 2009–10 (last) to 1998–00 (first)
	1998–2010	1998–2000	2001–2002	2003–2004	2005–2006	2007–2008	2009–2010	Last – first period (% difference)	p-value
Total	3,187	390	545	524	346	538	844	--	--
Mean Age	61 (12.7)	58 (14.0)	59 (13.2)	60 (12.4)	62 (12.6)	63 (11.6)	62 (12.2)	6.9%	<0.0001
% female	53.9	49.7	55.8	57.8	53.8	54.8	51.7	3.9%	0.49
Age group
<50	18.1	24.9	23.8	19.7	15.3	13.2	14.6	−41.4%	<0.0001
50–64	38.7	35.6	38.3	42.7	39.0	36.2	39.1	9.7%	0.24
65–79	38.6	36.4	35.6	31.3	40.5	46.1	40.5	11.3%	0.16
≥80	4.3	3.1	2.2	5.1	4.6	4.1	5.7	84.7%	0.047
Hospital volume
<5	34.6	37.2	29.0	35.7	44.5	39.2	29.4	−21.0%	0.006
5–9	23.9	17.7	21.3	19.7	32.4	28.6	24.8	40.0%	0.006
10–14	10.7	9.0	4.0	12.4	0	10.2	19.3	115.3%	<0.0001
15–24	14.0	13.8	17.3	20.0	15.3	8.0	13.0	−5.9%	0.69
≥25	16.4	22.3	28.4	12.2	7.8	13.9	13.5	−39.4%	<0.0001
Underlying diagnosis
Osteoarthritis	61.9	56.7	56.5	60.3	72.8	67.8	60.7	7.0%	0.18
Rheumatoid arthritis	6.7	10.8	8.8	7.6	3.8	5.8	4.9	−54.9%	0.0001
Fracture	0.1	0	0.5	0	0	0	0	0%	-
Avascular necrosis	0.7	0.5	0.9	1.1	0.3	0.7	0.5	−7.8%	-
Traumatic arthropathy	18.3	21.0	24.2	17.1	11.8	11.9	20.5	−2.2%	0.83
Other	12.3	11.0	9.0	13.7	11.3	13.7	13.5	22.5%	0.22
Deyo-Charlson score
0	71.3	73.6	73.2	75.2	73.4	66.9	68.4	−7.1%	0.06
1	23.6	24.1	24.9	21.2	21.7	23.6	24.8	2.7%	0.82
≥2	5.1	2.3	1.8	3.6	4.9	9.5	6.9	197.4%	0.001

-, small numbers did not allow for a comparison