0
    286
    views

    Use of Stems in Revision TKA: Press-Fit vs. Cement for Fixation

    Dr. Wayne Paprosky and Dr. Craig Israelite share their reasons for using stems in revision total knee arthroplasty procedures, as well as their preferred fixation method.

    After more than 30 years of performing total hip and total knee replacement procedures, Wayne G. Paprosky, MD, knows what he’s talking about when he says, “a revision knee arthroplasty is a complex procedure and should not be taken lightly.”

    One of the key issues is ensuring stability, which can be a challenge due to ligament insufficiency and inadequate bone stock for solid fixation of the prosthesis. The knee has already failed once; absent a stable foundation, the revision will fail too.

    At ICJR’s recent Revision Hip & Knee Course, Dr. Paprosky and Craig L. Israelite, MD, discussed their use of stems to provide needed stability in revision total knee arthroplasty (TKA) and made the case for their preferred fixation method: press-fit or cement.

    Use of Press-Fit Stems

    Bony surfaces are compromised in patients who need a revision procedure. Stems help recreate a stable joint that is oriented similarly to its normal anatomic axis.

    In about 95% of his revision patients, Dr. Paprosky, from Midwest Orthopaedics at Rush and Cadence Health Joint Replacement Institute in Chicago, Illinois, uses a press-fit stem with good diaphyseal engagement to accomplish his goals of stability and intramedullary alignment of the tibia and femur.

    He noted that loss of supporting bone in revision TKA causes increased transmission of forces across the joint, which can lead to early failure. Stems distribute the force away from the joint line. This allows the components to provide a rigid plate at the joint line, transmitting forces from the joint line through the stem to the metaphyseal and diaphyseal bone.

    Dr. Paprosky’s indications for using stems include:

    • Tibial defects requiring augments or bone grafts
    • Femoral bone defects requiring distal augments or bone grafts
    • Use of a constrained prosthesis
    • Toggling of trial components on host bone
    • Inadequate quality of bone to support implants

    He prefers to use longer, canal-filling stems, as they provide more support in rotational and bending planes and give him accurate intramedullary alignment. To be prepared, he advises templating for 2 different stem lengths in case of impinging or undersized stems during the procedure.

    Inserting a press-fit stem can sometimes be problematic. Issues typically occur on the tibial side due to anatomic discrepancy secondary to bone loss, abnormal proximal tibial flexion, or tibia vara. In these cases, correct component position and tibial rotation can be difficult to achieve.

    The solution, Dr. Paprosky said, is off-set stems that allow for correct component position and good canal fill of the stem.

    In cases with larger bone defects, Dr. Paprosky combines stems with trabecular metal cones for good metaphyseal fit and fill.

    Click the image below to watch Dr. Paprosky’s presentation from the Revision Hip & Knee Course.

    Use of Cemented Stems

    Dr. Israelite, from the University of Pennsylvania School of Medicine in Philadelphia, agrees with Dr. Paprosky that consideration for using stems in revision TKA is essential. He highlighted the following advantages to stems in these procedures:

    • Enhanced component stability
    • Decreased stress at the implant-to-bone surfaces
    • Load sharing to the diaphyseal cortex
    • Protection of host bone and minimization of migration
    • Enhanced alignment

    Unlike Dr. Paprosky, Dr. Israelite prefers cemented stem fixation in revision TKA. He gave the following as the pros and cons of using cemented stems:

    Advantages of Cemented Stems

    • Excellent early fixation
    • Long-term stem fixation
    • Accommodation of canal deformities
    • Antibiotic delivery in the cement
    • Possibility of using shorter stems than with cementless fixation, with the same mechanical stability
    • Preferred when using constraint

    Disadvantages of Cemented Stems

    • Potential for malalignment associated with short stems
    • May be associated with more stress shielding
    • Removal can be difficult

    Unfortunately, a review of basic science articles comparing press-fit stems, cemented stems, and hybrid fixation does not provide a clear answer as to which fixation technique is superior, Dr. Israelite said. [1-4]

    Kim et al [5] reported better results with cemented stems when using a constrained prosthesis. Only 10% of knees with cemented stems showed an incomplete radiolucent line of less than 1 mm at the proximal tibia versus 34% in the hybrid fixation group. In the hybrid fixation group, 7% of the knees showed circumferential radiolucent lines greater than 2 mm and were revised.

    Two studies from Mayo Clinic by Murray and Whaley [6, 7] reported on long-term outcomes of a monoblock, cemented stemmed revision prosthesis. Survival at 10 years of follow-up was found to be 96.7%.

    Another study by Mabry et al [8] from Mayo Clinic reported on long-term outcomes of revision TKA using a modular cemented stemmed prosthesis. They found 92% survivorship at 10 years of follow-up.

    A 2011 study by Sah and Paprosky [9] found that modified hybrid fixation of revision TKA using a diaphyseal-engaging stem and cementing only in the metaphysis was durable at 5 years of follow-up.

    Dr. Israelite also discussed the issue of stem pain after cementless revision TKA. Mihalko and Whiteside [10] found that more than 16% of patients had pain at the end of the press-fit stem and advised that this complication should be explained to patients prior to revision surgery.

    Stem pain also occurs with cemented stems, Dr. Israelite said, but not to the same extent as with uncemented stems.

    A 2015 meta-analysis by Wang et al [11] compared cemented and cementless stem fixation in revision TKA. They found no significant difference for any reason between the 2 fixation methods, and based on available literature, no superiority of any type of stem fixation was found.

    Dr. Israelite drew the following conclusions about cemented stems in revision TKA:

    • He finds them to be technically easier to use.
    • If necessary, the cement can provide antibiotic delivery into the canal.
    • Cemented stems are less dependent on the diaphyseal anatomy and provide immediate fixation.
    • It is generally possible to use shorter and thinner stems when using cement fixation.
    • Cemented stems are easier to remove than ingrowth/ongrowth devices.
    • Studies report less risk of diaphyseal “stem tip” pain and periprosthetic fracture with cemented stems.

    Current clinical results favor revision TKA with cemented stems, Dr. Israelite concluded; however, the literature lacks a high level of evidence – most studies are level 4 – and more randomized, prospective, controlled studies would be valuable.

    Click the image below to watch Dr. Israelite’s presentation from the Revision Hip & Knee Course.

    References

    1. Skwara A, Figiel J, Knott T, et al. Primary stability of tibial components in TKA: in vitro comparison of two cementing techniques. Knee Surgery, Sports Traumatology, Arthroscopy 17(10): 1199, 2009
    2. Beckmann J, Lüring C, Springorum R, et al. Fixation of revision TKA: a review of the literature. Knee Surg Sports Traumatol Arthrosc 2011;19:872–879
    3. Jazrawi LM, Bai B, Kummer FJ, Hiebert R, Stuchin SA. The effect of stem mod- ularity and mode of fixation on tibial component stability in revision total knee arthro- plasty. J Arthroplasty 2001;16:759–767
    4. Completo A, Rego A, Fonseca F, et al. Biomechanical evaluation of proximal tibia behaviour with the use of femoral stems in revision TKA: an in vitro and finite element analysis. Clin Biomech (Bristol, Avon) 2010;25:159–165
    5. Kim YH, Kim JS. Revision total knee arthroplasty with use of a constrained condylar knee prosthesis. J Bone Joint Surg Am. 2009;91(6):1440-7.
    6. Murray PB, Rand JA, Hanssen AD. Cemented long-stem revision total knee arthroplasty. Clin Orthop Relat Res. 1994;309:116–123
    7. Whaley AL, Trousdale RT, Rand JA, Hanssen AD. Cemented long-stem revision total knee arthroplasty. J Arthroplast. 2003;18(5):592
    8. Mabry TM, Vessely MB, Schleck CD, Harmsen WS, Berry DJ. Revision total knee arthroplasty with modular cemented stems: long-term follow-up. J Arthroplast. 2007;22(6):100
    9. Sah AP, Shukla S, Della Valle CJ, Rosenberg AG, Paprosky WG. Modified hybrid stem fixation in revision TKA is durable at 2 to 10 years. Clin Orthop Relat Res. 2011;469:839–846
    10. Mihalko WM , Whiteside LA. Stem pain after cementless revision total knee arthroplasty. Journal of Surgical Orthopaedic Advances 2015, 24(2):137-139
    11. Wang C, Pfitzner T, von Roth P, Mayr HO, Sostheim M, Hube R. Fixation of stem in revision of total knee arthroplasty: cemented versus cementless-a meta-analysis. Knee Surg Sports Traumatol Arthrosc. 2016 Oct;24(10):3200-3211. Epub 2015 Dec 19.