Ostomy Prior to TKA is not associated with increased risk of PJI or all-cause revision.
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Methods
Summary of included patients
Initial data query yielded a total of 409,806 cases in 320,605 patients. Revision cases where the corresponding primary case was not found in the database (e.g., because the primary occurred prior to the study period or outside of New York state) were excluded (10,372 cases in 7,694 patients). Additional cases with illogical or inconsistent data, likely to be the result of medical coding errors, were removed (e.g., patients greater than 2 primary cases or more than 1 primary case of the same laterality). A total of 314,656 patients underwent 382,221 TKAs during the study period. For the purposes of this analysis, only patients with >= 2 years of postoperative follow up were included, leaving a final cohort of 216,037 TKAs in 182,298 patients.
Results
Demographics
| Characteristic | History of Ostomy | p-value2 | |
|---|---|---|---|
| Ostomy Prior to THA, N = 1,1031 | No Ostomy Prior to THA, N = 381,1181 | ||
| Indication | <0.001 | ||
| OA | 769 (69.7%) | 289,880 (76.1%) | |
| Inflammatory arthritis | 2 (0.2%) | 847 (0.2%) | |
| Other or Unspecified | 332 (30.1%) | 90,391 (23.7%) | |
| Age (years) | 68.9 +/- 9.4 | 66.2 +/- 9.9 | <0.001 |
| Sex | 0.039 | ||
| Female | 671 (60.8%) | 243,238 (63.8%) | |
| Male | 432 (39.2%) | 137,875 (36.2%) | |
| Race | <0.001 | ||
| White | 956 (86.7%) | 279,507 (73.3%) | |
| Black | 53 (4.8%) | 36,696 (9.6%) | |
| Hispanic | 53 (4.8%) | 29,908 (7.8%) | |
| Asian | 8 (0.7%) | 8,410 (2.2%) | |
| Native American | 2 (0.2%) | 1,161 (0.3%) | |
| Other or Unknown | 31 (2.8%) | 25,436 (6.7%) | |
| Elixhauser score | 1.7 +/- 5.6 | 0.4 +/- 4.3 | <0.001 |
| Insurance | <0.001 | ||
| Private | 356 (32.3%) | 167,431 (43.9%) | |
| Medicare | 677 (61.4%) | 181,967 (47.7%) | |
| Medicaid | 29 (2.6%) | 11,742 (3.1%) | |
| Worker's Compensation | 30 (2.7%) | 15,870 (4.2%) | |
| Other | 11 (1.0%) | 4,108 (1.1%) | |
| Follow-up duration (years) | 3.0 +/- 2.6 | 3.3 +/- 3.0 | <0.001 |
| 1 n (%); Mean +/- SD | |||
| 2 Fisher’s Exact Test for Count Data with simulated p-value (based on 2000 replicates); One-way ANOVA; Pearson’s Chi-squared test | |||
| Characteristic | History of Ostomy | p-value2 | |
|---|---|---|---|
| Ostomy Prior to TKA, N = 6191 | No Ostomy Prior to TKA, N = 215,4181 | ||
| Indication | 0.001 | ||
| OA | 492 (79.5%) | 183,740 (85.3%) | |
| Inflammatory arthritis | 1 (0.2%) | 318 (0.1%) | |
| Other or Unspecified | 126 (20.4%) | 31,360 (14.6%) | |
| Age (years) | 68.3 +/- 9.2 | 66.1 +/- 10.0 | <0.001 |
| Sex | 0.071 | ||
| Female | 380 (61.4%) | 139,714 (64.9%) | |
| Male | 239 (38.6%) | 75,704 (35.1%) | |
| Race | <0.001 | ||
| White | 542 (87.6%) | 162,441 (75.4%) | |
| Black | 30 (4.8%) | 19,955 (9.3%) | |
| Hispanic | 30 (4.8%) | 16,185 (7.5%) | |
| Asian | 1 (0.2%) | 2,809 (1.3%) | |
| Native American | 2 (0.3%) | 664 (0.3%) | |
| Other or Unknown | 14 (2.3%) | 13,364 (6.2%) | |
| Elixhauser score | 1.7 +/- 5.4 | 0.6 +/- 4.3 | <0.001 |
| Insurance | <0.001 | ||
| Private | 195 (31.5%) | 94,042 (43.7%) | |
| Medicare | 381 (61.6%) | 104,189 (48.4%) | |
| Medicaid | 19 (3.1%) | 5,655 (2.6%) | |
| Worker's Compensation | 19 (3.1%) | 9,365 (4.3%) | |
| Other | 5 (0.8%) | 2,167 (1.0%) | |
| Follow-up duration (years) | 4.9 +/- 2.1 | 5.5 +/- 2.3 | <0.001 |
| 1 n (%); Mean +/- SD | |||
| 2 Fisher’s Exact Test for Count Data with simulated p-value (based on 2000 replicates); Welch Two Sample t-test; Pearson’s Chi-squared test | |||
Outcomes
| Characteristic | History of Ostomy | p-value2 | |
|---|---|---|---|
| Ostomy Prior to TKA, N = 6191 | No Ostomy Prior to TKA, N = 215,4181 | ||
| Length of hospital stay (days) | 3.6 +/- 3.1 | 3.3 +/- 1.8 | 0.017 |
| Discharge disposition | 0.191 | ||
| Home | 306 (49.4%) | 112,782 (52.4%) | |
| Skilled Nursing Facility | 232 (37.5%) | 70,451 (32.7%) | |
| Inpatient Rehabilitation | 76 (12.3%) | 30,805 (14.3%) | |
| Transfer | 5 (0.8%) | 1,225 (0.6%) | |
| Against Medical Advice | 0 (0.0%) | 62 (0.0%) | |
| Discharged to Court | 0 (0.0%) | 71 (0.0%) | |
| Hospice | 0 (0.0%) | 20 (0.0%) | |
| Expired | 0 (0.0%) | 0 (0.0%) | |
| Unknown | 0 (0.0%) | 2 (0.0%) | |
| ED presentation within 3 months | 88 (14.2%) | 24,077 (11.2%) | 0.017 |
| Readmission within 3 months | 84 (13.6%) | 16,699 (7.8%) | <0.001 |
| Readmission within 12 months | 137 (22.1%) | 27,364 (12.7%) | <0.001 |
| All-cause revision | 23 (3.7%) | 10,068 (4.7%) | 0.259 |
| Revision for PJI | 11 (1.8%) | 3,127 (1.5%) | 0.499 |
| Time to first revision (years) | 1.2 +/- 1.3 | 2.4 +/- 2.1 | <0.001 |
| Reoperation within 3 months of primary | 8 (1.3%) | 1,133 (0.5%) | 0.018 |
| Reoperation within 12 months of primary | 12 (1.9%) | 3,237 (1.5%) | 0.374 |
| 1 Mean +/- SD; n (%) | |||
| 2 Welch Two Sample t-test; Fisher’s Exact Test for Count Data with simulated p-value (based on 2000 replicates); Pearson’s Chi-squared test; Fisher’s exact test | |||
Figure: Kaplan-Meier plots demonstrating (A) probability of PJI-free primary TKA survival and (B) probability of all-cause revision-free primary TKA survival. Based on log-rank test comparing the survival curves between patients with a history of colostomy or ileostomy prior to TKA and those without a history of prior ostomy, there is no significant difference in time to event. Note: y-axis is limited to 90-100% survival.
Cox proportional hazards
| Characteristic | Time to PJI | Time to All-Cause Revision | ||||
|---|---|---|---|---|---|---|
| HR1 | 95% CI1 | p-value | HR1 | 95% CI1 | p-value | |
| Ostomy Prior to TKA | ||||||
| No Ostomy Prior to TKA | — | — | — | — | ||
| Ostomy Prior to TKA | 1.48 | 0.93, 2.36 | 0.095 | 0.97 | 0.68, 1.38 | 0.860 |
| Age (years) | 0.98 | 0.98, 0.98 | <0.001 | 0.96 | 0.96, 0.96 | <0.001 |
| Sex | ||||||
| Female | — | — | — | — | ||
| Male | 1.87 | 1.76, 1.99 | <0.001 | 1.23 | 1.19, 1.28 | <0.001 |
| Elixhauser score | 1.04 | 1.04, 1.05 | <0.001 | 1.02 | 1.02, 1.03 | <0.001 |
| Operative indication | ||||||
| Unspecified | — | — | — | — | ||
| OA | 0.79 | 0.73, 0.85 | <0.001 | 0.91 | 0.87, 0.96 | <0.001 |
| Inflammatory arthritis | 0.66 | 0.27, 1.58 | 0.346 | 0.70 | 0.43, 1.15 | 0.161 |
| Obesity | ||||||
| No | — | — | — | — | ||
| Yes | 1.40 | 1.31, 1.50 | <0.001 | 1.08 | 1.04, 1.13 | <0.001 |
| DM | ||||||
| No | — | — | — | — | ||
| Yes | 1.10 | 1.02, 1.19 | 0.017 | 0.97 | 0.93, 1.02 | 0.249 |
| History of smoking | ||||||
| No | — | — | — | — | ||
| Yes | 1.41 | 1.27, 1.57 | <0.001 | 1.18 | 1.11, 1.26 | <0.001 |
| 1 HR = Hazard Ratio, CI = Confidence Interval | ||||||
Table: Cox proportional hazards models evaluating the effect of ostomy prior to TKA on PJI (left) and all-cause revision (right). When controlling for the covariates listed, there is no significant effect of ostomy prior to TKA.
GLM for risk of revision
| Characteristic | OR1 | 95% CI1 | p-value |
|---|---|---|---|
| Ostomy Prior to TKA | |||
| No | — | — | |
| Yes | 1.21 | 0.62, 2.09 | 0.536 |
| Age (years) | 0.98 | 0.97, 0.98 | <0.001 |
| Sex | |||
| Female | — | — | |
| Male | 1.82 | 1.70, 1.96 | <0.001 |
| Elixhauser score | 1.04 | 1.03, 1.05 | <0.001 |
| Operative indication | |||
| Unspecified | — | — | |
| OA | 1.09 | 0.98, 1.20 | 0.118 |
| Inflammatory arthritis | 0.48 | 0.08, 1.49 | 0.298 |
| Obesity | |||
| No | — | — | |
| Yes | 1.32 | 1.22, 1.43 | <0.001 |
| DM | |||
| No | — | — | |
| Yes | 1.15 | 1.05, 1.25 | 0.002 |
| History of smoking | |||
| No | — | — | |
| Yes | 1.35 | 1.19, 1.52 | <0.001 |
| 1 OR = Odds Ratio, CI = Confidence Interval | |||
Table: Logistic regression model demonstrating the odds of revision for PJI for patients undergoing TKA with at least 2 years of follow-up. When controlling for the effects of age, gender, Elixhauser score, operative indication, obesity, DM, and smoking history, the main effect of ostomy prior to TKA is not associated with an increased risk of PJI.
