Stages of patient selection for inclusion in study: primary care data
| Included | Excluded | |
| Patients with primary knee replacement in CPRD GOLD (64 071) | ||
| → | Outcome (knee revision) and index event (primary surgery) outside England: 5397 (8.4%); Wales 6982 (10.9%) | |
| → | Outcome (knee revision) and index event: 31 395 (42.9%) | |
| Patients with primary knee replacement in CPRD GOLD linked to HES and used in survival analysis (22 836) | ||
| → | Primary surgery after 2011 (allowing for 5 years of follow-up): 5458 (23.9%) | |
| Patient with primary knee replacement used in the survival analysis (17 378) | ||
CPRD, Clinical Practice Research Datalink; HES, Hospital Episode Statistics.