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Implant Removal in Revision Total Knee Arthroplasty


Algorithm

This algorithm presents the approach for implant removal in total knee arthroplasty.

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Chapter Synopsis

Implant extraction should be performed cautiously and with attention to avoiding iatrogenic damage. A systematic and preplanned approach obviates the need for unwanted intraoperative creativity.

Important Points

Be conservative in making your way through the bone–implant interface by using thin and flexible instruments. Make sure you undermine the implants as much as possible before slamming them out.

Surgical Pearls

  • Provide adequate exposure in order to reach the bone–implant interface.

  • Use thin and flexible sawblades or osteotomes.

  • Undermine the implants as much as possible.

  • Consider a tibial tubercle osteotomy or femoral slot in cases with well-fixed stems.

Surgical Pitfalls

  • Subtotal undermining can cause major damage to the underlying bone during component extraction.

  • Failure to address the well-fixed keel or stem may lead to fracture or inability to remove the implant.

Introduction

Component extraction is not always the easiest aspect of the revision procedure, and it can lead to unnecessary additional damage or increased complexity if performed without sufficient patience or attention.

No absolute truth or consensus exists regarding the optimal strategy for implant removal, and surgical practices may differ based on personal insights and experience. Supportive data from the literature are lacking on this subject.

It is obvious that implant extraction should be performed cautiously and with attention to avoid iatrogenic damage. A systematic and preplanned approach facilitates removal and also avoids the need for the surgeon to rely on his or her intraoperative creativity.

This chapter describes a step-by-step approach that can serve as a basis even for the inexperienced surgeon who is only occasionally confronted with revision total knee arthroplasty (TKA). My colleagues and I have used this algorithm since 2001 at our institution, and more than 450 revision TKAs have been performed following this protocol.

The algorithm consists of twelve consecutive steps that are executed always in the same order. The intention of this chapter is not to convince the reader to follow this algorithm meticulously but to suggest how component removal can be performed in a preplanned way that has provided excellent results.

Equipment

The following equipment is required:

  • Motorized oscillating saw

  • Thin flexible sawblades (width 15 to 20 mm)

  • Set of thin osteotomes (widths ranging from 7.5 to 40 mm)

  • System-specific (in situ) tibial insert introducer/extractor

  • Standby: cerclage wire set or large fragment screw set

Surgical Technique

1

Start by Removing the Polyethylene Insert

The arthrotomy of the knee usually does not achieve adequate exposure for revision TKA, and additional release of peripatellar adhesions and resection of scar tissue are often required. Removal of the polyethylene tibial insert can facilitate this process dramatically, because the tension in the peripatellar and femorotibial soft tissue structures will immediately become reduced by removal of the space-occupying insert ( Fig. 11.1 ). Extraction of the polyethylene insert is usually easy and can be performed with the use of a lever that is either implant specific or generic. For example, the tip of a standard Hohmann retractor inserted between the plastic and the baseplate serves well for this purpose. Systems using a screw or interlocking part can equally easily be dealt with by using the implant-specific instruments. Prior knowledge of the system specifications is required, and it is the responsibility of the surgeon to prepare accordingly.

FIGURE 11.1, Start by removing the polyethylene insert, because this will reduce capsular tension and increase the working space.

If a monoblock or all-polyethylene tibial component is in place, its postpone its removal until after removal of the femoral component. Its removal at this stage would be severely compromised because the femur is sitting in the way.

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