Design: Systematic review and meta-analysis of retrospective cohorts (Level III)
Population: 44 studies, 3,317 patients under 25 (5,632 joints)
Primary outcome: Complications, function, quality of life and all-cause revision
Effect: Revision 8.7% after THA, 12.4% after TKA; PJI 1.6% and 2.9%

This JBJS Reviews meta-analysis, published 23 September, pooled 44 studies of 3,317 patients (5,632 joints) under 25 who had total hip or knee replacement for end-stage joint disease.

After hip replacement, pooled rates were 1.6% for periprosthetic joint infection, 5.4% for aseptic loosening, 1.4% for periprosthetic fracture and 8.7% for all-cause revision. Function and quality of life improved substantially. After knee replacement, infection was 2.9%, aseptic loosening 9.9% and all-cause revision 12.4%. More recent cohorts had lower revision and infection rates after hip replacement.

For a young patient with a destroyed joint from juvenile arthritis, avascular necrosis or dysplasia, replacement is a legitimate option. The counselling should be explicit that a second operation within their lifetime is likely, and knee replacement fares worse than hip.

Offer hip or knee replacement to young patients with end-stage joint disease when other options are exhausted.
Counsel that revision risk is roughly 9% after hip and 12% after knee replacement in this age group.
Expect higher infection and loosening rates than in older adults.
Plan implant choice and bone stock preservation with future revision in mind.

Why it matters

Gives surgeons numbers for a consent conversation that usually relies on extrapolation from older adults.

The statistics, in plain English

The functional improvement (SMD 4.9) is very large, reflecting how disabled these patients are before surgery. Pooled revision rates come from retrospective series with varied follow-up, so they are best read as approximate.