Foot & Ankle International - June 2017 - 644

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Foot & Ankle International 38(6)

Table 1. Distribution of Discharges, Average Length of Stay, and Costs by Patient and Hospital Characteristics for TAR and Revision
in NIS 2011.
TAR/Revision
Discharges

All discharges
Age group
d18
18-<44
45-64
65-84
t85
Missing
Payer
Medicare
Medicaid
Private insurance
Uninsured
Other
Missing
Owner
Government
Private, not-for-profit
Private, for-profit
Missing
Teaching status
Nonteaching
Teaching
Missing
Region
Northeast
Midwest
South
West

All Hospital Discharges

TAR/Revision
Length of Stay

TAR/Revision Costs ($)

Count

Percentage

Count

Percentage

Mean

Median

Mean

Median

3528

100.0

38 590 733

100.0

2.4

2.0

19 057

18 033

-
186
1690
1615
31
6

0.0
5.3
47.9
45.8
0.9
0.2

5 664 403
9 385 257
9 694 504
10 533 410
3 283 176
29 982

14.7
24.3
25.1
27.3
8.5
0.1

-
3.0
2.4
2.4
3.4
2.0

-
3.0
2.0
2.0
3.0
2.0

-
22 483
19 714
18 484
18 572

-
20 348
19 080
17 608
17 236

1676
128
1566
10
148
-

47.5
3.6
44.4
0.3
4.2
0.0

15 336 984
7 577 744
12 231 289
2 068 277
1 266 698
109 742

39.7
19.6
31.7
5.4
3.3
0.3

2.3
2.8
2.5
4.1
2.4
-

2.0
2.0
2.0
5.0
2.0
-

18 762
17 878
19 402
19 045
19 715
-

17 522
17 738
18 800
15 625
19 060
-

289
2686
552
-

8.2
76.1
15.7
0.0

4 077 570
28 523 067
5 464 655
525 441

10.6
73.9
14.2
1.4

2.1
2.5
2.3
-

2.0
2.0
2.0
-

23 533
19 007
16 619
-

22 208
18 097
17 648
-

1494
2034
-

42.3
57.7
0.0

19 721 459
18 343 833
525 441

51.1
47.5
1.4

2.3
2.5

2.0
2.0

19 303
18 331

19 318
17 061

499
1324
857
848

14.1
37.5
24.3
24.0

7 528 258
8 768 800
14 802 929
7 490 746

19.5
22.7
38.4
19.4

2.4
2.6
2.4
2.2

2.0
2.0
2.0
2.0

17 416
17 939
19 332
21 325

15 326
16 274
19 228
21 196

Source: KNG Health Consulting, LLC Analysis of the 2011 Nationwide Inpatient Sample (NIS).
Abbreviation: TAR, total ankle replacement.

the number of orthopedic surgeries performed at the hospital, other than those related to ankle and foot, the higher the
hospital's propensity to perform TAR. The relationship
between a hospital's performance of TAR surgeries and its
overall margin was not statistically significant.
Poisson regression estimates indicate that among hospitals that had at least 1 TAR case, the number of TAR cases
performed was negatively associated with hospital size and
positively associated with the average margin on TAR
cases. We found that the rate of TAR surgeries was 53.9%
and 70.5% lower for medium and large hospitals, respectively, compared to small hospitals (IRR=0.461 and
IRR=0.295). Although the relationship between the average
TAR margin and the number of TAR surgeries performed
was statistically significant, the magnitude of this relationship was small. If the average TAR margin in the study

sample were to increase from -30% to +30%, the average
number of TAR cases would increase from 3.4 to 4.1.

Discussion
Because of improvements in instrumentation design and
reproducibility in its technique, use of total ankle arthroplasty in treating end-stage ankle arthritis has increased
considerably.17,18,23 Investigations by Raikin et al18 and
Pugely et al17 have demonstrated that over the past 5 years,
there has been a dramatic increase in hospital volume of
these procedures. Further, utilization has increased in those
patients with greater medical and operative complexity. A
recent cross-sectional study demonstrated that the performance of TAR increased 60% during a 6-year span.23
Coupled with this rise in utilization, a greater number of
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