Surgical technique of metaphyseal sleeves and cones

In Part 1 of this newsletter we outlined how metaphyseal fixation of revision TKA can be performed with structural allograft, cones, or sleeves. Nowadays, most surgeons prefer cones or sleeves over allograft, so we have focused on these two treatment techniques here. In addition to describing the surgical techniques, we also interviewed one advocate for cone and one for sleeve technique with the aim of providing a balanced overview of each technique. 


Surgical technique using cones

After removing the previous components, the remaining bone is thoroughly cleaned of residual cement, fibrous, and nonviable tissue. This facilitates a correct assessment of the actual bone loss to properly prepare the bone for the correct cone size. While residual tissue may hinder osseointegration of the ingrowth surface, residual cement may even damage or deflect the instruments used to prepare for the cone during bone preparation creating excess bone loss or even fracture.

The position of the bony defect in relation to the intramedullary canal can be estimated with trial cones. The trial cones can be placed upside down on the bone surface over the reamer to assess the size and orientation of the defect and correct placement of the cone.

Various manufacturers provide different methods to guide alignment. All systems have in common that they use the medullary canal as the reference point to fix the guide. Depending on the manufacturer, fixed templates or variable dials are attached to the initial guide (Figure 1), which then allow exact placement of the instrumentation.



Once the guide and the template are in place, the cavity is prepared by cutting at a trajectory that mills or reams the bone to exactly match the shape of the implant. Since cones achieve their stability through press-fit, a good seating of the cone in the bone (Figure 2) is paramount for primary stability, which is the basis for osseointegration (Figure 3).


This is done with sequentially sized reamers, broaches, rasps, or burrs in a stepwise manner. It is important to pay particular attention to the amount of bone that is being removed. Enough bone should be removed to create a circumferential fit of the cone, however, one must ensure that bone is not removed excessively, because this may increase the risk of fracture.

While there is considerable variation in the techniques between the individual manufacturers, the instruments possess marks, which delineate the size and depth of the corresponding cone.

There may be cases in which the shape of the defect makes it impossible to create a perfect circumferential press fit on all sides of the cone due to bone loss being more prominent on one side compared to the other. In such situations, voids may be filled with morselized graft, demineralized bone matrix, or a suitable synthetic bone substitute. This is tightly packed around the cone until maximal stability is ascertained. This maneuver is not only to enhance the primary stability but also to prevent cement from flowing into the interface between cone and host bone when the final component is cemented into position.


Read the full article with your AO login

  • Positioning of the cone
  • Surgical technique using sleeves
  • Interview with David Dalury and Bryan Springer: cones versus sleeves

Part 1 | Indications for the use of metaphyseal fixation in revision total knee replacement

Part 3 | Outcomes of revision total knee arthroplasty using metaphyseal sleeves and cones

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Contributing experts

This series of articles was created with the support of the following specialists (in alphabetical order):

Omar Behery

Atrium Health Musculoskeletal Institute
Charlotte, United States

David F Dalury

University of Maryland St Joseph Hospital
Towson, United States

Glen Purnomo

St. Vincentius a Paulo Catholic Hospital
Surabaya, Indonesia

Bryan D Springer

Atrium Health Musculoskeletal Institute
Charlotte, United States

Seng-Jin Yeo

Singapore General Hospital

This article was compiled by Elke Rometsch, Project Manager Medical Writing, AO Foundation, Switzerland.