Table 1.
Reasons for conversion of UKA to TKA with the number and percentage for which stemmed or revision models were used
| Main reason for UKA conversion | Total | Standard implant | Stemmed/revision implant | ||
|---|---|---|---|---|---|
| Number | Percent | Number | Number | Percent | |
| Loosening | 347 | 37.7 | 278 | 69 | 19.9 |
| Progress | 299 | 32.5 | 272 | 27 | 9.0 |
| Knee pain | 105 | 11.4 | 92 | 13 | 12.4 |
| Wear | 48 | 5.2 | 42 | 6 | 12.5 |
| Instability | 47 | 5.1 | 41 | 6 | 12.8 |
| Patella | 21 | 2.3 | 20 | 1 | 4.8 |
| Fracture | 18 | 2.0 | 10 | 8 | 44.4 |
| Other | 27 | 2.9 | 21 | 6 | 22.2 |
| Missing | 8 | 0.9 | 8 | 0 | 0.0 |
UKA = unicompartmental knee arthroplasty.