Distal Femoral Replacement With a Metaphyseal Sleeve: Outcomes and Risk Factors for Subsidence

Abstract

In this study, we report on the outcomes of our experience using a metaphyseal sleeve with a distal femoral replacement (DFR) and review the risk factors for sleeve subsidence over a 3 year period.

Keywords: Distal femur replacement; Limb preservation system; Metaphyseal sleeve; Outcome.

Figure 1

Postoperative radiographs of a second-stage revision left total knee replacement utilizing the LPS metaphyseal sleeve.

Figure 2

Determining the degree of subsidence and cortical thickness using postoperative anteroposterior radiographs: degree of sleeve exposure (e) and cortical thickness (c) at the distal femur. Determined for (A) medial and (B) lateral sides [4].

Figure 3

Serial radiographs of a migrating sleeve; (a) previous revision with a constrained total knee arthroplasty (TKA). (b) First stage following infection with a static spacer (humeral nail and cement), followed by the (c-d) second stage requiring wiring of femoral fracture adjacent to the sleeve and stem. (e-g) Progressive migration of the implant to the piriformis fossa. (h) Conversion to DFR with LPS stem

Figure 4

Serial radiographs of a migrating sleeve; (a-b) Previous revision with a unconstrained total knee arthroplasty (TKA). (c-d) First stage following infection with a static cement spacer. (e-f) Second stage with prophylactic wiring of the femoral. (g) Migration of the implant seen at 3 months to (h) final position at 12 months.

Figure 5

Serial radiographs of a failing sleeve; (a) previous revision with a cemented long femoral stem. (b-c) Single-stage revision with fracture to medial cortex and wire fixation. (d-f) progressive disintegration of fracture and loosening of sleeve. (g-h) Revised to a DFR with LPS stem.

Figure 6

Diagramatic representation of the sleeve position in the metaphysis compared to its use as distal femoral replacement (red line represents the contact area).