Spontaneous dislocation of the polyethylene component following knee revision arthroplasty: case report

Abstract

Dislocation of the polyethylene component in knee arthroplasty is a rare complication. The main triggering factor is failure of the locking mechanism, which may result from technical errors of insertion, trauma or even implant failure. Here, a case of dislocation of the polyethylene component from the tibial base, nine years after revision arthroplasty, is reported. It is believed that this is the first such case reported in the Brazilian literature.

Dislocation of the polyethylene insert following fixed-bearing total knee arthroplasty: A case report

“…There have been a few cases reported in the literature of spontaneous dislocation, however no clear cause has been identified. The most popular opinion is that repeated posterior compressive forces can cause lift off of the anterior rim overtime leading to spontaneous dislocation [2][3][4][5][6] . From a biomechanical perspective, flexion movements particularly when starting from full extension cause greater posterior load as tibial-femoral contact moves in a posterior direction leading to force applied in an antero-superior direction.…”

“…Total knee arthroplasty (TKA) is a commonly performed orthopaedic operation and is shown to have excellent longevity and patient satisfaction [1] . There are many complications associated with TKA described in the literature such as post-operative infection and stiffness, periprosthetic fracture and polyethylene insert wear over time [1,2] . Dislocation of the polyethylene insert is a very rare and easily missed complication with only a few cases described in the literature.…”

Would You Reduce this Knee?

“…Dislocation of the polyethylene component of knee arthroplasty is a rare complication. The real incidence is unknown, 1 and only a few cases have been reported. 1 While dislocation of this component can be diagnosed on plain radiographs, it may be easily missed due to radiolucency of polyethylene.…”

“…The real incidence is unknown, 1 and only a few cases have been reported. 1 While dislocation of this component can be diagnosed on plain radiographs, it may be easily missed due to radiolucency of polyethylene. As with any knee dislocation, these injuries may be associated with injury to the popliteal vessels.…”