Table 3.
Comparison of TKA recipients, before and after matching.
| Before matching | After matching | |||||
|---|---|---|---|---|---|---|
| Short cases | Long cases | p-value | Short cases | Long cases | Standardized difference | |
| Number of patients | N = 35,753 | N = 56,590 | N = 17,815 | N = 17,815 | ||
| Demographics | ||||||
| Age (y) [Median (IQR)] | 68 (62–75) | 67 (61–74) | <0.001 | 68 (61–75) | 68 (61–74) | 0.01 |
| Female [N (%)] | 23,500 (65.7%) | 33,307 (58.9%) | <0.001 | 11,237 (63.1%) | 11,237 (63.1%) | 0 |
| Rural residence [N (%)] | 4725 (13.2%) | 10,726 (19.0%) | <0.001 | 2914 (16.4%) | 2924 (16.4%) | 0 |
| Income Quintile [N (%)] | <0.001 | |||||
| Lowest | 5796 (16.2%) | 10,043 (17.7%) | 3099 (17.4%) | 3149 (17.7%) | 0.01 | |
| 2 | 7453 (20.8%) | 11,698 (20.7%) | 3731 (20.9%) | 3715 (20.9%) | 0 | |
| 3 | 7495 (21.0%) | 11,449 (20.2%) | 3635 (20.4%) | 3665 (20.6%) | 0 | |
| 4 | 7361 (20.6%) | 11,657 (20.6%) | 3670 (20.6%) | 3617 (20.3%) | 0.01 | |
| Highest | 7563 (21.2%) | 11,610 (20.5%) | 3634 (20.4%) | 3626 (20.4%) | 0 | |
| Co-morbidities [N (%)] | ||||||
| Coronary artery disease | 1095 (3.1%) | 1864 (3.3%) | 0.052 | 552 (3.1%) | 566 (3.2%) | 0 |
| Congestive Heart Failure | 1746 (4.9%) | 3035 (5.4%) | 0.001 | 809 (4.5%) | 944 (5.3%) | 0.04 |
| Chronic Obstructive Pulmonary Disease | 6292 (17.6%) | 10,988 (19.4%) | <0.001 | 3195 (17.9%) | 3319 (18.6%) | 0.02 |
| Counseled about smoking cessation | 1478 (4.1%) | 2401 (4.2%) | 0.422 | 834 (4.7%) | 684 (3.8%) | 0.04 |
| Diabetes | 10,026 (28.0%) | 17,069 (30.2%) | <0.001 | 5060 (28.4%) | 5414 (30.4%) | 0.04 |
| Hypertension | 25,936 (72.5%) | 41,897 (74.0%) | <0.001 | 12,711 (71.3%) | 13,376 (75.1%) | 0.08 |
| Frail | 2013 (5.6%) | 3470 (6.1%) | 0.002 | 950 (5.3%) | 1092 (6.1%) | 0.03 |
| BMI >40 | 344 (1.0%) | 1156 (2.0%) | <0.001 | 127 (0.7%) | 127 (0.7%) | 0 |
| Charlson Score [N (%)] | <0.001 | |||||
| 0 | 26,076 (72.9%) | 39,552 (69.9%) | 12,969 (72.8%) | 12,463 (70.0%) | 0.06 | |
| 1 | 6241 (17.5%) | 10,660 (18.8%) | 3119 (17.5%) | 3380 (19.0%) | 0.04 | |
| 2 | 2279 (6.4%) | 4066 (7.2%) | 1162 (6.5%) | 1271 (7.1%) | 0.02 | |
| 3 or more | 1157 (3.2%) | 2312 (4.1%) | 565 (3.2%) | 701 (3.9%) | 0.04 | |
| Type of anesthesia | ||||||
| General Anesthesia [N (%)] | 4579 (12.8%) | 11,342 (20.0%) | <0.001 | 2426 (13.6%) | 2426 (13.6%) | 0 |
| Complication | Short cases | Long cases | p-value | Short cases | Long cases | p-value |
|---|---|---|---|---|---|---|
| Deep infection [N (%)] | 236 (0.7%) | 603 (1.1%) | <0.001 | 108 (0.6%) | 195 (1.1%) | <0.0001 |