An artificial joint , especially in young patients with congenital hip disease (CHD), has the likelihood of revision after certain years of function. This may delay, even for 30 or more years, but sometimes will occur as patient remains active.

For that reason, the follow-up of patients with total hip replacement (THR) for a lifetime and revision at the appropriate time is of fundamental importance (Fig. 10.1). The decision for the time of revision belongs to the surgeon, in contrast to the decision for the primary replacement which is taken in consultation with the patient.

Revision of THR, previously performed for CHD, has a wide spectrum of difficulty. It can be from a rather simple isolated polyethylene insert exchange to the need for megaprosthesis .

If the patient has a proper follow-up and a severe wear of the usually small diameter polyethylene is detected early, an isolated exchange with concomitant femoral head exchange may suffice, provided that both components are stable and the polyethylene locking mechanism is intact (Figs. 11.​27, 11.​28, 11.​29, 11.​30 and 11.​31). We have found, however, that companies do not always keep spare inserts for this exchange, thus the surgeon is forced to do a larger operation with consequences to the already defective bone stock and the economy.

Timely revision , before extensive bone destruction, may give to the patient several more years of a good quality’s life (Figs. 10.2 and 10.3).

Cemented and cementless devices, used in the primary THR, have different failure mechanisms . Loosening remains the major problem of the cemented all-polyethylene acetabular components (Fig. 10.4). Radiographically the acetabular component is considered to be definitely loose when there is migration of >2 mm in the vertical or horizontal direction. In the presence of a circumferential radiolucent line , up to 2 mm, without migration or a change of the position, the component is considered as probably loose [1]. A probably loose cemented acetabular component does not need an argent revision. It can be survived for many more years (Fig. 10.5). Also, wear of the polyethylene of a cemented component, without progressive osteolysis, does not need forthwith revision. It can last for years without osteolysis and loosening (Fig. 10.6). On the other hand, cementless acetabular components present other potential causes of failure , mainly the possibility of early wear of the liner that has been documented in earlier designs (Fig. 10.7). We should be aware that the processes of wear and osteolysis are initially symptomless.