Table 1.
Baseline Characteristics of patients with a primary procedure code for either lower extremity total joint arthroplasty
| Baseline Characteristics: Values given are frequencies with (%) unless noted. |
Primary Total Knee Arthroplasty N = 322,894 |
Primary Total Hip Arthroplasty N = 192,553 |
|---|---|---|
| Patient-level variables | ||
|
| ||
| Age – median (IQR) | 68 (60, 75) | 68 (57, 76) |
| - 18-59 | 76,399 (23.66%) | 58,542 (30.40%) |
| - 60-67 | 75,509 (23.38%) | 36,373 (18.89%) |
| - 68-74 | 80,308 (24.87%) | 40,549 (21.06%) |
| - 75+ | 90,679 (28.08%) | 57,088 (29.65%) |
|
| ||
| Gender | ||
| - Male | 114,333 (35.41%) | 81,404 (42.28%) |
| - Female | 208,556 (64.59%) | 111,140 (57.72%) |
|
| ||
| Race | ||
| - White | 186,669 (57.81%) | 116,106 (60.30%) |
| - Black | 16,786 (5.20%) | 8,676 (4.51%) |
| - Hispanic | 12,945 (4.01%) | 4,356 (2.26%) |
| - Asian/Pacific Islander | 2,210 (0.68%) | 1,021 (0.53%) |
| - Native American | 458 (0.14%) | 216 (0.11%) |
| - Other | 3,840 (1.19%) | 2,058 (1.07%) |
| - Missing | 99,986 (30.97%) | 60,120 (31.22%) |
|
| ||
| Charlson Score | ||
| - 0 | 216,431 (67.03%) | 135,660 (70.45%) |
| - 1 | 81,679 (25.30%) | 43,046 (22.36%) |
| - 2+ | 24,784 (7.68%) | 13,848 (7.19%) |
|
| ||
| Income level | ||
| - $1-24,999 | 9,668 (2.99%) | 5,056 (2.63%) |
| - $25,000-34,999 | 59,780 (18.51%) | 29,596 (15.37%) |
| - $35,000-44,999 | 85,242 (26.40%) | 46,519 (24.16%) |
| - ≥$45,000 | 161,058 (49.88%) | 107,238 (55.69%) |
| - Missing | 7,146 (2.21%) | 4,144 (2.15%) |
|
| ||
| Insurance Status (Primary payer): | ||
| - Private | 106,892 (33.12%) | 73,194 (38.03%) |
| - Medicare | 196,317 (60.83%) | 108,971 (56.62%) |
| - Medicaid | 7,632 (2.37%) | 5,242 (2.72%) |
| - Dual Medicare/Medicaid* | 15,665 (4.85%) | 9,056 (4.70%) |
| - Other (incl. Self-pay) | 11,908 (3.69%) | 5,076 (2.62%) |
|
| ||
| Provider-level variables | ||
|
| ||
| Hospital Region | ||
| - Northeast | 59,306 (18.37%) | 42,108 (21.87%) |
| - Midwest | 86,930 (26.92%) | 49,437 (25.67%) |
| - South | 117,440 (36.37%) | 61,486 (31.93%) |
| - West | 59,219 (18.34%) | 39,522 (20.53%) |
|
| ||
| Hospital Setting | ||
| - Urban | 276,641 (85.68%) | 169,438 (88.00%) |
| - Rural | 46,253 (14.32%) | 23,115 (12.00%) |
|
| ||
| Hospital teaching status | ||
| - Non-teaching | 182,023 (56.37%) | 95,428 (49.56%) |
| - Teaching | 140,872 (43.63%) | 97,126 (50.44%) |
|
| ||
| Hospital Bed Size | ||
| - Small | 46,690 (14.46%) | 28,212 (14.65%) |
| - Medium | 79,576 (24.64%) | 44,228 (22.97%) |
| - Large | 196,629 (60.90%) | 120,113 (62.38%) |
|
| ||
| Surgeon Volume (Cases/year) | ||
| - TKA: 1-17; THA:1-10 | 49,080 (15.20%) | 30,925 (16.06%) |
| - TKA: 18-35; THA:11-21 | 50,974 (15.79%) | 26,599 (13.81%) |
| - TKA: 36-66; THA: 22-52 | 47,610 (14.74%) | 28,450 (14.78%) |
| - TKA: ≥67; THA: ≥53 | 48,962 (15.16%) | 28,572 (14.84%) |
| - Missing | 126,269 (39.11%) | 78,008 (40.51%) |
|
| ||
| Hospital Volume (Cases/year) | ||
| - TKA: 1-100; THA: 1-64 | 83,060 (25.72%) | 50,248 (26.10%) |
| - TKA: 101-197; THA: 65-123 | 83,791 (25.95%) | 47,925 (24.89%) |
| - TKA: 198-293; THA:124-224 | 76,898 (23.82%) | 48,628 (25.25%) |
| - TKA: ≥293; THA: ≥225 | 79,146 (24.51%) | 45,751 (23.76%) |
|
| ||
| Hospital Ownership | ||
| - Government or Private | 190,951 (59.14%) | 124,914 (64.87%) |
| - Public | 17,722 (5.49%) | 9,005 (4.68%) |
| - Private Non-profit | 65,964 (20.43%) | 33,837 (17.57%) |
| - Private For-profit | 29,701 (9.20%) | 14,852 (7.71%) |
| - Private (Unspecified) | 18,556 (5.75%) | 9,945 (5.16%) |
|
| ||
| Unadjusted average Length of Stay (LOS) | 3.74 (±1.43) | 3.90 (±1.43) |