Table I.
Bi-unicondylar arthroplasty compared to matched healthy controls and total knee arthroplasty subjects: demographic details and gait characteristics at top walking speeds, Oxford Knee Score, and EuroQol five-level five-dimension questionnaire.
| Subject | Healthy | Bi-UKA | TKA |
|---|---|---|---|
| Number of knees | 24 | 22 | 22 |
| Sex, M:F | 14:10 | 14:8 | 12:10 |
| Mean age, yrs | 63 (8) | 68 (13) | 67 (10) |
| Mean BMI, kg/m2 (SD) | 27 (5) | 28 (5) | 27 (4) |
| Mean height, cm (SD) | 173 (10) | 174 (8) | 174 (11) |
| Mean months post-surgery (SD) | 23 (20)* | 52 (51)* | |
| Median months post-surgery (IQR) | 17 (8 to 33) | 24 (16 to 76) | |
| Mean top walking speed, km/h (SD) | 7.4 (0.7) | 6.7 (0.9)* † | 5.6 (0.7)* † |
| Mean Hof speed, H (SD) | 0.7 (0.1) | 0.7 (0.1)* † | 0.6 (0.1)* † |
| Mean weight acceptance rate, BW/s (SD) | 10.8 (3.5) | 10.5 (4.0) | 7.9 (3.8) |
| Mean maximum weight acceptance force, BW (SD) | 1.6 (0.2) | 1.4 (0.1)* † | 1.3 (0.2)* † |
| Mean mid-stance force, BW (SD) | 0.5 (0.1) | 0.6 (0.1)* † | 0.7 (0.1)* † |
| Mean push-off force, BW (SD) | 1.0 (0.2) | 1.0 (0.1) | 1.0 (0.1) |
| Mean push-off rate, BW/s (SD) | 4.3 (1.0) | 4.0 (0.8) | 3.8 (0.9) |
| Mean step length, cm (SD) | 85 (10) | 82 (8)* | 73 (7)* † |
| Mean stride length, cm (SD) | 170 (20) | 163 (15)* | 150 (16)* † |
| Mean step width, cm (SD) | 13 (3) | 14 (3) | 13 (3) |
| Mean cadence, step/min (SD) | 60 (5) | 57 (6)* | 52 (5)* † |
| Mean impulse, BW/s (SD) | 385 (21) | 377 (23) | 380 (29) |
| Mean double support time, s (SD) | 0.28 (0.1) | 0.29 (0.1)* | 0.34 (0.1)* † |
| Mean gait cycle time, s (SD) | 2.0 (0.2) | 2.1 (0.2)* | 2.3 (0.2)* † |
| Mean contact time, s (SD) | 1.3 (0.1) | 1.4 (0.1)* | 1.5 (0.1)* † |
| Mean OKS (SD) | 40.9 (7.1)* | 36.0 (5.3)* | |
| Median OKS (IQR) | 42 (38 to 47)* | 38 (31 to 39)* | |
| Mean EQ-5D (SD) | 0.91 (0.1)* | 0.80 (0.1) * | |
| Median EQ-5D (IQR) | 0.94 (0.88 to 0.95)* | 0.83 (0.74 to 0.89)* |
Significant difference between implant groups (Demographics: RMANOVA, Gait: Mann–Whitney U test, significance p < 0.05 with Bonferroni correction).
Significant difference implant versus healthy control (Mann-Whitney U test, significance p < 0.05 with Bonferroni correction).
Bi-UKA, bi-unicondylar arthroplasty; BW, normalized to body weight; EQ-5D, EuroQol five-dimension questionnaire; IQR, interquartile range; OKS, Oxford Knee Score; RMANOVA, repeated measures analysis of variance; SD, standard deviation; TKA, total knee arthroplasty.