Cemented Femoral Stems - Wheeless' Textbook of Orthopaedics

- See: Total Hip Replacement Menu:
- Cemented Femoral Component: Loosening:
- Collar: in THR
- Optimal Cementing Technique
- Removal of Cemented Femoral Stems:

- Indications:
- cemented femoral stems probably remain gold standard for total hip arthroplasty;
- most indicated in older patients (more than 65 yrs), but are also used in younger patients since there is some indications
that cemented stems are less prone to develop osteolysis;
- useful for patients w/ "stove pipe" type femur, previous fracture, or previous osteotomy since these
patients would not be expected to achieve a tight fit which is necessary for ingrowth;
- may be indicated poor bone quality such as RA, osteoporosis, or Paget's disease;
- in the report by MA Harrington et al, the authors determined that in a stair-climbing test model, the peak proximal cement strains
were increased more by changes in body wt than they were by changes in neck length. Even during stair-climbing,
calcar-collar contact reduced peak cement strains;
- the peak strain magnitudes in the proximal cement mantle were increased more by changes in body weight than by changes
in the length of the neck of the stem;
- strong effect of stem size on the cement strains suggests that cemented femoral stems should not be used in heavy
patients with small medullary canals that require a small cemented stem;
- ref: Cemented femoral fixation: a historical footnote.
- outcomes:
- in the study by JJ Callaghan MD et al (J Bone Joint Surg [Am] 82-A: 487-97, 2000) the authors followed Charnley Total Hip Arthroplasty
patients (with cement) with a minimum 25 year follow up;
- of the 327 hips for which the outcome was known after a minimum of 25 years, 295 (90 %) had retained the original implants until
the patient died or until the most recent follow-up examination;
- of the 62 hips in patients who lived for at least 25 years after the surgery, 48 (77 %) had retained the original prosthesis;

- Cemented Component Design:
- prosthesis should have relatively smooth surfaces, w/ no sharp edges, so that sites of stress concentration are eliminated from both prosthesis and cement;
- a prosthesis that is broader laterally than medially may help to diffuse the compressive stress medially;
- tapered shape from proximal to distal allows controlled subsidence within the cement column;
- cobalt-chromium alloy stems are used in most stems, since they generate less particulate debris than titanium implants;
- triple taper concept: femoral component tapers to a point in both the AP and lateral planes and in addition, the stem is more narrow medially and widens laterally;
- references:
- Survivorship analysis of cemented high modulus total hip arthroplasty.
- Effects of Femoral Neck Length, Stem Size, and Body Weight on Strains in the Proximal Cement Mantle MA. Harrington Jr., MD. JBJS (Am) 84:573-579 (2002)
- The design features of cemented femoral hip implants.
- Analysis of 16 retrieved proximally cemented femoral stems.

- Component Surface:
- there is controversy about how much bonding should occur between the cement and the femoral stem;
- excessive bonding between the cement and stem may transfer wt bearing stress to the bone-cement interface, leading to loosening;
- in contrast, excessive motion between the cement-metal interface, may lead to excessive osteolysis and rapid loosening;
- definitions:
- polished: (Ra less than 1 micrometer) polished stems create little abrasion;
- matte: (Ra less than 2 micrometer) matte finnish will not create excessive abrasion unless stem allows large micomotion;
- rough: (Ra greater than 2 micrometer) expected to cause excessive abrasion;
- some are proponents of smooth surface, which may allow subsidence and thereby keeps the cement in compressive loading;
- many components have a matt finish, which allows some mechanical interlock with the cement;
- in the study by DW Howie et al (JBJS Vol 80-B, 1998), 4/20 matt coated stems had been revised for aseptic loosening whereas
0/20 polished stems had been revised (9 year minimum follow up);
- in the study by DK Collis et al, the authors evaulated loosening in grit blasted versus polished stems;
- study included 244 consecutive total hip arthroplasties with a cemented femoral component performed by one surgeon;
- 4 hips treated with the grit-blasted stem had aseptic loosening with substantial surrounding lysis and required revision;
- an additional two hips in this group had radiographic evidence of substantial lysis and were judged to have an impending need for revision;
- no hip treated with the polished stem required revision, and only one had minimal lysis;
- this difference regarding failures and impending failures was significant (p = 0.05);
- references:
- Loosening of matt and polished cemented femoral stems. DW Howie et al. JBJS. Vol 80-B. No 4. July 1998 p 573.
- Comparison of Clinical Outcomes in Total Hip Arthroplasty Using Rough and Polished Cemented Stems with Essentially the Same Geometry
Dennis K. Collis, MD. The Journal of Bone and Joint Surgery (American) 84:586-592 (2002)
- The skeletal response to matt and polished cemented femoral stems.
- Effects of design changes on cemented tapered femoral stem fixation.
- Loosening of matt and polished cemented femoral stems.
- Early loosening of the femoral component at the cement-prosthesis interface after total hip replacement.
- A Rough Surface Finish Adversely Affects the Survivorship of a Cemented Femoral Stem.
- Long-term results of use of a collared matte-finished femoral component fixed with second-generation cementing techniques. A fifteen-year-median follow-up study.
- Radiographic Failure Patterns of Polished Cemented Stems.

- Cement Technique:
- in the report by Michael F. Shepard, MD et al, the authors performed an experimental study on cement technique;
- they determined that when using a roughened or precoated cemented femoral component, the surgeon should consider
cementing earlier with wetter cement to maximize the cement-prosthesis bond;
- when implanting a polished femoral component, it is preferable that the cement is doughy, because the cement-
prosthesis bond is not influenced by the wetness of the cement and it is easier to maintain the
orientation of the femoral component.

- references:
- Influence of Cement Technique on the Interface Strength of Femoral Components. MF. Shepard, MD CORR 2000;2000:26-35
- Loosening of the femoral component after use of the medullary-plug cementing technique. Follow-up note with a minimum five-year follow-up.
- Pressurized cement fixation in total hip arthroplasty.
- Do we need to vacuum mix or centrifuge cement
- Patterns of osteolysis around total hip components inserted with and without cement.
- The prevalence of femoral osteolysis associated with components inserted with or without cement in total hip replacements. A retrospective matched-pair series.
- The results of improved cementing techniques for total hip arthroplasty in patients less than fifty years old. A ten-year follow-up study.
- Radiolucency at the bone-cement interface in total knee replacement. The effects of bone-surface preparation and cement technique.
- 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.
- Total hip arthroplasty with use of so-called second-generation cementing techniques. A fifteen-year-average follow-up study.

- Cement Mantle:
- current recommendations are to have at least 2 mm of a uniform cement mantle around the femoral component;
- in the study by RP Joshi et al (JBJS Vol 80-B, 1999), the authors found that a 3 mm cement mantle around the femoral component, and a
6 mm mantle around the acetabular component were associated with the lowest incidence of osteotlysis;
- references:
- Changes in the calcar femoris in relation to cement technology in total hip replacement. F Bocco et al. COOR. Vol 128. 1977. p 287-295.
- The cement mantle in total hip arthroplasty. Analysis of long-term radiographic results.
- Osteolysis after Charnely primary low friction arthroplasty. A comparison of two matched paired groups. RP Joshi et al. JBJS Vol 80-B. No 4. July 1998. p 585.
- Should the cement mantle around the femoral component be thick or thin?
- Cement microcracks in thin-mantle regions after in vitro fatigue loading.
- Importance of a thin cement mantle. Autopsy studies of eight hips.

- Grading of Cement Technique: (Barrack et. al. JBJS 1992 and Mulroy et.al. 1995)
- grade A: meduallary canal completely filled w/ cement (white out).
- grade B: a slight radiolucency exists at the bone cement interface.
- grade C: a radiolucency of more than 50% at the bone cement interface.
- grade D: a radiolucency involving more than 100% of the interface between bone and cement in any projection, including absence of cement distal to the stem tip;
- note: this grading system has been criticized since it is somewhat influenced by the amount of cancellous bone removed during reaming and broaching;
- when the entire cancellous bed is removed, there will often be "white out" (indicating good cementing technique), and yet
there will be no cancellous foothold for the cement;
- cement mantle:
- as noted by Mulroy et.al. 1995, a femoral cement mantle less than 1 mm and defects in the cement mantle are associated with early loosening;
- Jasty et al 1990, noted that cement voids and stem abutment against the femur (indicating an inadequate cement mantel) were associated w/ loosening;
- similarly, Maloney et al 1990, note that circumferential cement mantles with component centralization prevents loosening;
- references:
- Bone lysis in well fixed cemented femoral components. Maloney WJ et al, JBJS Vol 72-B. 1990. p 966-970.
- Radiographic comparison of cementing techniques in total hip arthroplasty.

- Cement Disease:
- references:
- Cement disease.
- Cardiac arrest during hip arthroplasty with a cemented long-stem component. A report of seven cases.
- Bone lysis in well-fixed cemented femoral components