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Cementing Technique for THR


- See: Total Hip Replacement Menu:
          - Addition of Antibiotics to Cement:
          - Cemented Femoral Component Loosening:
          - Insertion of Cemented Femoral Stems:

- Discussion:
    - first generation technique:
          - finger packing technique, w/o use of pressurization (no cement gun and no medullary plug), and no reduction of porosity (centerfuge);
          - aseptic loosening may be as high as 30% at 10 years (Stauffer RN. (1982));    
          - references:
                  - Ten-year follow-up study of total hip replacement

    - modern cementing techniques:
          - medullary brush;
          - cement restrictor (either plastic or cement plug);
          - meduallary pusaltile lavage
          - insertion of adrenaline-soaked sponges
          - reduction of cement porosity (centerfuge)
          - precoating of the stem w/ cement (controversial)
                 - note that methods to increased bonding between the stem and the cement may actually lead to early loosening in some cases;
          - cement centralizers (applied to femoral stem tip)
          - cement gun for retrograde insertion and pressurization
          - pressurization: may be performed with surgeon's gloved finger or may be performed w/ a wedge shaped pressurization device which is pushed into the medullary canal;
     - hazards:
          - cement disease: 
          - insufficient cement:
                 - when using a new implant, always check w/ the manufacturing representative to ensure two 40 gm bags of cement are sufficient;
          - bone-cement radiolucencies:
                 - etiology may stem from thermal necrosis from large volumes of cement and 2% shrinkage which occurs w/ cement hardening;

- PreCementing Checklist:
    - optimize the exposure:
          - it is important to realize that total hip arthroplasty can be performed thru a fairly small
                  incision, but in contrast, careful insertion of a cemented femoral stem requires a
                  larger exposure inorder to avoid varus/valgus and anteversion/retroversion abnormalities;
                  - w/ an excessively small exposure, the femoral component will torque on the soft tissues (which creates cement voids) as the component is driven downward;
                  - check the adequacey of the exposure by hand inserting an under-sized broach component down the canal to ensure that the
                          surgeon's fingers (or the insertion jig) do not get in the way of a smooth femoral stem insertion;
    - calcar planning:
          - this step is necessary to maximize contact w/ the femoral collar;
          - countersink final broach size approx 2 mm below femoral neck cut;
          - for prosthesis w/ collar, use calcar planer to make final adjustments of collar against medial aspect of femoral neck cortex;
    - check anteversion:
          - prior to cementing, recheck femoral neck anteversion, by testing where component touches calcar (also ensure that component will
                   not be placed in varus);
          - once cement is injected, its illegal to rotate femoral component w/ in canal because this will create voids w/in cement;
    - trochanteric osteotomy wires:
          - if trochanter has been removed wires are introduced before cement is inserted and a further trial reduction then carried out;
    - canal plugging: (cement restrictor)
          - silastic plug is placed 1 to 1.5 cm distal to femoral stem tip (use a pen to mark the insertion rod at the proper distance as measured 
                  either off of the trial broach or stem);
          - some authors (Russotti, et al (1988)) argue that at least 2 cm of distal cement is necessary to prevent progressive radiolucency;
                  - other authors agrue that only 1-1.5 cm of distal cement is needed since the bigger stems used today achieve fit by wedging 
                          (not end bearing);
                  - in addition, w/ revision surgery, there is nothing worse than have to remove more than 2 cm of cement;
          - use largest silastic plug possible, becuase a small plug may be forced distally by the pressurized cement;
          - plug is inserted by hammering, which prevents sudden plunging, which might otherwise occur w/ hand insertion;
          - after restrictor is in place, reinsert femoral stem to ensure that there is adequate room;
          - w/ plug in place, no further bleeding will come from the canal;
          - references:
                  - Loosening of the femoral component after use of the medullary-plug cementing technique. Follow-up note with a minimum five-year follow-up
                  - Cemented total hip arthroplasty with contemporary techniques. A five-year minimum follow-up study.
    - removal of debris from femur:
          - may begin cement mixing while preparing bone bed for cement;
          - loose cancellous bone debris, blood, and tissue are removed w/ water pick & brush are helpful, & routine mechanical drying of both 
                  acetabular & femoral surfaces is important (continue water pick until returning fluid is clear);
          - apply dilute solution of Epi w/ moist sponge (prevents blood interposition)
          - use hypotensive anesthesia to reduce bleeding during cementing;
          - references:
                  - Medullary lavage reduces embolic phenomena and cardiopulmonary changes during cemented hemiarthroplasty.
                  - An in vitro study of femoral intramedullary pressures during hip replacement using modern cement technique.
                  - High-volume, high-pressure pulsatile lavage during cemented arthroplasty.
                  - The role of lavage in preventing hemodynamic and blood gas changes during cemented arthroplasty
    - clean field:
          - before inserting cement, keep field as dry as possible to optimize cement bonding;
          - an "illegal sponge" can be placed in the acetabulum and over the abductors;
          - suction:
                  - sucker tip should be changed, since contamination rate exceeds 50% after 100 min;
                  - in fact, it is often most useful to have a backup suction apparatus ready since the primary suction tubing often becomes partially 
                          clogged w/ debris during the lateral part of the case;
    - components on the field:
          - ensure that all components are on the field, and all insertion instruments are ready;
    - minimize risk of DVT:
          - consider use of intraoperative IV heparin to reduce the risk of DVT in THR;

- Cement Mixing: 
    - see vaccum mixing:
    - in some situations, the addition of antibiotics may be appropriate;
    - total joint replacement following renal or liver transplantation carries a risk of joint infection of appoximately 19%;
    - these patients will have a high relative mortality rate;
    - references:
          - The effect of centrifuging bone cement.    
          - Do we need to vacuum mix or centrifuge cement?

- Cement Delivery;
    - insert cement into cement gun at 2 minutes, and insert into medullary canal at 3-4 minutes;
    - insertion of cement w/ decreased viscosity results in greater strength;
          - low viscosity prevents laminations which significantly weaken the polymerized cement mass;
    - delivering cement w/ syringe to allow retrograde filling;
          - the syringe in which the cement is loaded must have a nozzle long enough to reach cement restrict plug;

- Cement Pressurization:
    - often the surgeon will wait until the cement is slightly doughy (4-6 minutes) before pressurization, realizing that it is difficult to pressurize when the cement is watery;
    - cement that extrudes around side should not be folded back on top because it is usually contaminated w/ blood (add fresh cement);
    - after cement is filled, the cement is pressurized w/ a mechanical device or with pressure from a finger over a rubber dam;
    - hazards: if pressurizing devices are used, then be sure to check the cement in the canal (as opposed to the cement on the field) every 30 
             to 60 seconds to ensure that it is not "maturing" too quickly;
            - it is important to check the canal cement rather than the residual cement on the field because they may mature at different rates 
                    (which means that the canal cement is hardening while the cement on the field is still soft);
    - references:
            - Cement pressurisation during hip replacement.
            - Pressurized cement fixation in total hip arthroplasty.

- Femoral Stem Insertion:
    - cement is allowed to reach doughy state before components are inserted;
            - if cement is not doughy at insertion, there will not be maximum pressurization as the stem is inserted;
    - usually the component should be inserted at 5-6 minutes;
    - insert stem straight into canal w/ proper anteversion;
    - any twisting of stem once in canal will change anteversion;
    - component is held rigidly in place for 12-15 min while methacrylate hardens (polymerizes), fixing the implant to the bone

The femoral component in total hip arthroplasty. Six to eight-year follow-up of one hundred consecutive patients after use of a third-generation cementing technique.

Radiographic comparison of cementing techniques in total hip arthroplasty.

Loosening of the femoral component after use of the medullary-plug cementing technique. Follow-up note with a minimum five-year follow-up.

The results of improved cementing techniques for total hip arthroplasty in patients less than fifty years old. A ten-year follow-up study.

Revision hip arthroplasty with the use of cement and impaction grafting. Histological analysis of four cases.

The effect of the type of cement on early revision of Charnley total hip prostheses. A review of eight thousand five hundred and seventy-nine primary arthroplasties from the Norwegian Arthroplasty Register.

The cement mantle in total hip arthroplasty. Analysis of long-term radiographic results.

Optimum pore size for bone cement fixation.

Tissue response to particulate polymethylmethacrylate in mice with various immune deficiencies.

The effects of modern cementing techniques on the longevity of total hip arthroplasty

The effect of improved cementing techniques on component loosening in total hip replacement: an 11 year radiographic review

Effects of Preheating of Hip Prostheses on the Stem-Cement Interface.