Table 1.
Demographic features of study cohort as mean (SD) or n (%), unless specified otherwise
| Primary TKA | Revision TKA | |
|---|---|---|
| (n = 17,633) | (n = 4,090) | |
| Mean (SD) | Mean (SD) | |
| or n (%) | or n (%) | |
| Mean follow-up, years (SD) | 6.3 (4.7) | 5.1 (4.2) |
| Female | 9,781 (55%) | 2,084 (51%) |
| Bilateral | 4,719 (27%) | 804 (20%) |
| Mean age at surgery, years (SD) | 68.4 (10.0) | 67.9 (11.3) |
| Age category | ||
| ≤ 60 years | 3,352 (19%) | 915 (22.4%) |
| 61–70 years | 6,206 (35.2%) | 1,286 (31.4%) |
| 71–80 years | 6,493 (36.8%) | 1,476 (36.1%) |
| >80 years | 1,582 (9%) | 413 (10.1%) |
| Body mass index (BMI), kg/m2 (SD) | 31.2 (6.2) | 31.1 (6.5) |
| BMI category, kg/m2 | ||
| Missing | 67 (0.4%) | 36 (0.9%) |
| Normal, < 25.0 | 2,362 (13.4%) | 584 (14.4%) |
| Overweight, 25–29.9 | 5,961 (33.9%) | 1,363 (33.6%) |
| Obese, 30–39.9 | 7,710 (43.9%) | 1,731 (42.7%) |
| Morbidly obese, ≥ 40.0 | 1,533 (8.7%) | 376 (9.3%) |
| ASA class a | ||
| 1 | 291 (1.7%) | 50 (1.2%) |
| 2 | 9,614 (54.7%) | 1,869 (45.8%) |
| 3 | 7,544 (42.9%) | 2,098 (51.4%) |
| 4 | 117 (0.7%) | 61 (1.5%) |
| Mean Deyo-Charlson index (SD) | 1.5 (2.2) | 1.3 (2.1) |
| Deyo-Charlson index | ||
| 0 | 7,985 (45.3%) | 2,086 (51%) |
| 1 | 3,598 (20.4%) | 836 (20.4%) |
| 2 | 2,291 (13%) | 470 (11.5%) |
| 3+ | 3,759 (21.3%) | 698 (17.1%) |
| Previous cardiac event | ||
| No | 14,404 (81.7%) | 3,490 (85.3%) |
| Yes | 3,229 (18.3%) | 600 (14.7%) |
| Previous thromboembolic event | ||
| No | 16,869 (95.7%) | 3,873 (94.7%) |
| Yes | 764 (4.3%) | 217 (5.3%) |
| Operative diagnosis (primary TKR) | ||
| Osteoarthritis | 16,372 (92.8%) | |
| Rheumatoid arthritis | 657 (3.7%) | |
| Avascular necrosis | 152 (0.8%) | |
| Other b | 604 (3.4%) | |
| Operative diagnosis (revision TKR) | ||
| Failure: loose/wear/osteolysis | 2,154 (52.7%) | |
| Failure: previous surgery with | ||
| components removed | 801 (19.6%) | |
| Failure: fracture, dislocation | 877 (21.4%) | |
| Failure: non-union | 27 (0.7%) | |
| Failure: infection | 228 (5.6%) | |
| Implant fixation | Not applicable | |
| Uncemented | 1,555 (8.8%) | |
| Cemented or hybrid* | 16,078 (91.2%) |
a American Society of Anesthesiologists (ASA) score was missing in 67 (0.4%) of primary TKR patients and 12 (0.3%) of revision TKR patients
b Other diagnoses for primary TKA included: genu varum, genu valgum, hemophilia, Paget’s disease, failed previous disease including arthrodesis, failed previous osteotomy, failed previous patellectomy, Chacot arthropathy, chondromalacia, pigmented villonodular synovitis; data on operative diagnosis were missing for 3 patients with revision TKR.