Cement-in-Cement Femoral Revision

• Recurrent instability: the dominant indication. Extracting the stem and re-cementing a smaller stem allows adjustment of version (typically 10 to 15 degrees of rotational freedom within the down-sized mantle), increased offset, longer neck length, or a change to a dual-mobility or constrained-compatible head, without touching the femoral bone.
• Access for acetabular revision: a well-fixed taper-slip stem often obstructs acetabular exposure and reaming. Temporary stem removal with cement-in-cement re-insertion at the end of the case ("removal for access") is quicker and safer than working around the stem.
• Periprosthetic fracture: Vancouver B1 fractures fixed by plating where stem exchange improves construct mechanics; selected B2 fractures around taper-slip stems where the mantle remains attached and intact within the reduced fragments — reduce and fix the femoral tube, then cement a stem (often longer, still within or extending the mantle) in cement.
• Taper, trunnion or stem fracture with a well-fixed mantle: the broken proximal component is removed and a new stem cemented in cement (distal fragment extraction may still require a cortical window).
• Leg-length or offset correction at the time of another revision procedure.
• Polyethylene wear or head exchange where stem removal facilitates the acetabular work.

Absolute

• Proven or suspected periprosthetic joint infection.
• Loose mantle: continuous or progressive lucent lines at the cement-bone interface, migration, or intraoperative movement on stress testing.
• Fractured or fragmented cement mantle.
• Endosteal osteolysis behind the mantle (the mantle may look intact but is unsupported).

Relative

• Gross malposition of the original mantle (severe varus, extreme anteversion or retroversion) that the required correction cannot be achieved within.
• Composite-beam stem bonded to the mantle — extraction usually destroys the mantle; if the mantle survives extraction intact, the technique remains valid, but this is uncommon.
• Very thin original mantle or deficient proximal cement, leaving no room for a meaningful new layer even after down-sizing.
• Requirement for a substantially longer stem beyond the mantle where distal cement removal and canal preparation would be needed anyway (a hybrid "cement-in-cement proximally, new cement distally" construct is possible but technically demanding).

Radiographic assessment (AP pelvis, AP and lateral femur, compare serial films)

• Map lucencies by Gruen zones 1 to 14 (AP and lateral). Any continuous cement-bone lucency, any progressive lucency, or lucency in more than one zone should prompt suspicion.
• Look for mantle fracture (most common at the tip and calcar), stem subsidence beyond expected taper-slip engagement (Exeter stems normally subside within the mantle by about 1 mm in the first two years — subsidence of the mantle itself is pathological), pedestal formation and endosteal scalloping.
• Barrack cement grading from the index films, if available, informs the quality of the original mantle.

Intraoperative assessment

• After stem extraction, inspect the entire inner mantle under direct vision and with a light source: look for cracks, especially at the calcar and around the tip.
• Mechanically stress the mantle with an instrument — any movement at the cement-bone interface, fluid expressed at the margin, or a hollow feel mandates conversion to full cement removal.
• Send tissue for culture and histology in every case; have a bail-out plan (long-stem cemented or cementless revision) on the shelf.

Position: as per surgeon's revision approach — posterior approach is most versatile for combined acetabular work and version adjustment; lateral decubitus with secure supports.

Imaging and equipment: full-length femoral radiographs; templates for the down-sized stem (identify the extracted stem's brand and size from operation notes — critical); high-speed burr with long fine tips; pulse lavage with long nozzles; narrow suction; cement gun with revision (narrow) nozzle; low-viscosity cement, usually antibiotic-loaded; full revision tray including cement removal instruments and long stems as bail-out; stem extraction devices appropriate to the implant.

Preparation: exclude infection preoperatively (inflammatory markers, aspiration where indicated); consent for possible full revision, fracture, and cortical windowing; cell salvage available; tranexamic acid per protocol.

1. Approach and exposure: extend the previous incision; protect the sciatic nerve (posterior approach); clear the shoulder of the stem of all overhanging cement and soft tissue so extraction does not lever off the greater trochanter.
2. Extract the stem: a polished taper-slip stem is disimpacted with a punch on the extraction hole or a dedicated extractor, driven in line with the stem axis. It should slide out with modest force. Resistance suggests residual cement over the shoulder or a bonded stem — stop and reassess rather than fracture the trochanter.
3. Inspect and stress-test the mantle as above. Confirm intact, well fixed, no fracture.
4. Roughen: burr the entire inner surface to remove the glossy layer and create macroscopic pits and grooves; deliberately avoid thinning the mantle or breaching to bone. Some surgeons also relieve the proximal-medial mantle to gain version freedom.
5. Trial: insert the down-sized trial fully within the mantle; confirm it seats without abutment, achieves the planned version and depth, and that head trials restore stability, offset and length. The trial must not contact the old mantle wall at any point where new cement is needed.
6. Lavage and dry: pulse lavage the mantle interior to clear burr debris, then dry meticulously with narrow swabs on a clip and suction — repeat until bone-dry. Pack a dry swab until the moment of cementation.

1. Cement: mix low-viscosity antibiotic-loaded cement, ideally vacuum-mixed. Timing matters — inject early in the working phase while flow is optimal.
2. Inject retrograde with a narrow revision nozzle to the depth of the old mantle (no distal restrictor is needed — the old distal cement plug is the restrictor). Pressurise proximally with a seal.
3. Insert the definitive polished stem slowly along the axis of the old mantle to the trialled depth and version; hold position unwaveringly until the cement cures — micro-movement during polymerisation laminates the new layer.
4. Remove extruded cement, particularly posteriorly where it can impinge.
5. Trial reduce, select head length, assess stability through a full arc, impact the definitive head on a clean dry trunnion, reduce and repair soft tissues (posterior capsule and short external rotators if posterior approach).
6. At-risk structures: sciatic nerve, greater trochanter (extraction levering), femoral cortex (burr breach), abductors.
7. Aftercare: full weight bearing as tolerated in most cases (the construct is immediately stable); standard hip precautions per approach; radiographs to document the composite mantle as the new baseline; await intraoperative culture results before discharge planning.

• Wet mantle at cementation: the commonest technical failure — new cement will not interdigitate. Prevent with obsessive drying; if bleeding wells up from a mantle defect, that defect signals loss of integrity — convert.
• Incomplete seating: usually the stem abutting unroughened or unrelieved mantle, or cement injected too late. Prevent by thorough trialling and early injection. If the stem sits proud, extract immediately before cure and restart.
• Mantle fracture during preparation or insertion: convert to full revision.
• Unrecognised loosening discovered at surgery: convert — never cement into a mobile mantle.
• Positive intraoperative cultures postoperatively: manage as periprosthetic infection; the retained mantle complicates eradication and staged revision may follow — this is why preoperative exclusion of infection is emphasised.
• Failure of the construct later: revision is usually straightforward — the polished stem again extracts easily, and a further cement-in-cement or full revision can be performed.