Table 1.
Subject characteristics and differences by case (n=142) and control (n=426) status. Subjects in the two groups are matched on age, BMI, gender, KL-scores and race. Differences were assessed using independent t-tests or Pearson’s chi-squared test as appropriate. Data are expressed as unadjusted means ± SD. Significant p-values (p<0.05) are highlighted in bold.
| Controls (n=426) | Injury cases (n=142) | P-value Injury vs controls | |
|---|---|---|---|
| Age (years) | 59.61 ± 9.50 | 58.80 ± 9.26 | 0.376 |
| Body mass index (kg/m2) | 28.75 ± 4.04 | 29.40 ± 4.68 | 0.115 |
| Gender – Male [n (%)] | 168 (39.4%) | 55 (38.7%) | 0.882 |
| PASE score | 159.4 ± 85.6 | 173.9 ± 84.8 | 0.082 |
| WOMAC Pain | 2.29 ± 3.17 | 3.72 ± 3.57 | <0.001 |
| WOMAC Stiffness | 1.37 ± 1.54 | 2.18 ± 1.77 | <0.001 |
| WOMAC Disability | 6.81 ± 9.90 | 13.04 ± 12.71 | <0.001 |
| WOMAC Total Score | 10.44 ± 13.78 | 18.90 ± 17.12 | <0.001 |
|
| |||
| Baseline KL grade | 0.671 | ||
| KL 0 [n (%)] | 177 (40.8%) | 54 (38.7%) | |
| KL 1 [n (%)] | 69 (16.2%) | 22 (15.5 %) | |
| KL 2 [n (%)] | 180 (43.0%) | 66 (45.8%) | |
|
| |||
| Racial composition | 0.775 | ||
| Caucasian [n (%)] | 337 (79.1%) | 110 (76.8%) | |
| Other Non-white [n (%)] | 8 (1.9 %) | 4 (2.8%) | |
| African American [n (%)] | 81 (19.0%) | 28 (20.4%) | |
|
| |||
| OAI Risk factors | <0.001 | ||
| History of 1 knee injury [n (%)] | 0 (0.0%) | 105 (73.9%) | |
| History of 2 knee injuries [n (%)] | 0 (0.0%) | 24 (16.9%) | |
| History of 3 knee injuries [n (%)] | 0 (0.0%) | 13 (9.2%) | |
|
| |||
| Years since first injury | <0.001 | ||
| 0 – 5 years ago [n (%)] | - | 24 (16.9%) | |
| 6 – 10 years ago [n (%)] | - | 17 (12.0%) | |
| 11 – 20 years ago [n (%)] | - | 23 (16.2%) | |
| 21 – 30 years ago [n (%)] | - | 24 (16.9%) | |
| 31 – 40 years ago [n (%)] | - | 28 (19.7%) | |
| More than 40 years ago [n (%)] | - | 26 (18.3%) | |