Cemented, Uncemented and Hybrid Fixation in THR

Part of The Joint Replacement Guide — Phase 4: The Operation · Article 22 of 44 · Hip

Key Points

  • The socket and femoral stem of a hip replacement can each be fixed with or without bone cement.
  • The main combinations are fully cemented, fully uncemented and hybrid fixation.
  • The most appropriate choice depends on factors including bone quality, age, sex, anatomy, activity level, implant evidence and the surgeon’s experience.
  • UK registry data has helped surgeons understand how outcomes vary between different fixation methods, implants and patient groups.
  • Cemented, uncemented and hybrid replacements can all provide excellent long-term results when a well-established implant is used appropriately.

Understanding Fixation

A total hip replacement has two principal components:

  • an acetabular component, or socket, placed in the pelvis; and
  • a femoral stem, placed inside the upper part of the thigh bone.

These components do not necessarily have to be fixed in the same way. Consequently, describing an entire hip replacement simply as “cemented” or “uncemented” can sometimes conceal an important difference between how the socket and stem are secured.

Cemented Fixation

In a fully cemented hip replacement, both the socket and femoral stem are fixed using polymethylmethacrylate, usually abbreviated to PMMA and commonly called bone cement.

Despite its name, bone cement does not act like household glue. It fills and interlocks with the prepared surface of the bone, creating immediate mechanical fixation around the implant.

Cemented hip replacement was developed and refined as part of Sir John Charnley’s low-friction arthroplasty. It has the longest established clinical history of the main fixation methods. Modern cementing techniques and well-established cemented implants continue to produce excellent long-term results.[1]

Cemented femoral stems are particularly valuable where the bone may not provide dependable initial grip for an uncemented stem. This can include people with thinner or more fragile bone and some older patients, particularly older women at greater risk of fracture around the implant.

Cement use has its own considerations. Introducing cement and the femoral component can occasionally affect blood pressure, oxygen levels or the circulation during surgery. This is sometimes described as bone cement implantation syndrome. Serious reactions are uncommon in elective hip replacement, but the anaesthetic and surgical teams take appropriate precautions, particularly in patients with significant heart or lung disease.[2]

Uncemented Fixation

Uncemented components usually have a roughened, porous or specially coated surface. They are inserted so that they obtain a firm mechanical fit against the bone at the time of surgery. This is commonly described as a press-fit.

Over the following weeks and months, living bone grows onto—and with some surfaces into—the implant. This biological process is called osseointegration.

Successful uncemented fixation therefore involves two stages:

  1. sufficient stability when the implant is inserted; and
  2. subsequent bone growth onto or into its surface.

If an implant moves excessively before bone ingrowth occurs, reliable osseointegration may be less likely. The surgeon must therefore obtain stable fixation without applying so much force that the bone fractures.

Uncemented implants are commonly used in younger patients and in people with strong bone, but they are not restricted to a particular age group. Some modern uncemented stems also perform well in selected older patients. The result depends on the patient’s bone, the specific implant design and how it is inserted—not simply on whether cement was used.

Most patients can put weight through an uncemented hip soon after surgery if their surgeon and physiotherapist advise them to do so. Biological fixation takes time to develop, but this does not automatically mean that the leg must be kept non-weight-bearing.

Hybrid Fixation

A hybrid hip replacement normally combines:

  • an uncemented socket; and
  • a cemented femoral stem.

This is a well-established and widely used combination. It allows the surgeon to use biological fixation for the socket while obtaining immediate cemented fixation in the femur.

The opposite combination—a cemented socket with an uncemented stem—is called a reverse hybrid replacement. It is used less commonly but may be appropriate in selected circumstances.

Hybrid fixation is not a compromise or a halfway form of hip replacement. It is a deliberate combination that can provide excellent long-term results.[1,3]

What UK Registry Evidence Shows

The National Joint Registry reports outcomes according to age, sex, fixation method, bearing surface and the particular combination of implants used. Its findings show that fixation cannot be judged in isolation: two implants described as “uncemented,” for example, may have different designs and different outcomes.[1]

Registry evidence has generally supported greater consideration of cemented femoral fixation in patients with poorer bone quality or a higher risk of periprosthetic femoral fracture. Uncemented stem insertion can cause a fracture during surgery or leave some patients at greater risk of a fracture around the stem afterwards.

However, the evidence does not support a single age cut-off that is correct for everyone. Recent UK research suggests that the relationship between stem design, age, sex and subsequent reoperation is more complex than a simple “cemented for older people and uncemented for younger people” rule.[4]

For example, a collared uncemented stem may behave differently from an uncollared design. Men and women of the same age may also have different fracture risks because their average bone shape and quality may differ.

It is therefore more accurate to say that increasing age—particularly when accompanied by fragile bone—may strengthen the case for cemented femoral fixation, rather than making cement mandatory solely because a particular birthday has been reached.

How the Choice Is Made

Your surgeon may consider:

  • the quality and shape of your femur and pelvis;
  • your age and sex;
  • osteoporosis or other conditions affecting bone strength;
  • previous fractures or operations;
  • your activity level and general health;
  • the risk of fracture during or after implantation;
  • the established results of the proposed implant;
  • the risks associated with cement use; and
  • the surgeon’s training and experience with that fixation method.

Bone quality is commonly assessed from your medical history, examination and ordinary X-rays, and it is also assessed directly during surgery. A DEXA bone-density scan may be appropriate if osteoporosis is suspected or if the result would alter your wider medical care, but it is not routinely required solely to decide whether a hip replacement should be cemented.

Implant Evidence Matters Too

“Cemented,” “uncemented” and “hybrid” describe broad categories rather than individual products. The design and evidence supporting the particular stem and socket are also important.

NICE recommends using total hip replacement constructs with a revision rate—or a projected revision rate—of no more than 5% at ten years.[5] Surgeons may also use ratings from the Orthopaedic Data Evaluation Panel and information from national registries when selecting implants.

A well-established implant used for an appropriate patient is generally more reassuring than choosing a fixation category solely because it is newer or marketed as more advanced.

In More Depth

Modern cementing involves careful preparation of the femoral canal. This may include:

  • washing/drying the bone using pulsed lavage;
  • inserting a plug to contain the cement;
  • introducing the cement in a controlled manner; and
  • pressurising it so that it interlocks effectively with the surrounding bone.

For uncemented fixation, the surgeon progressively prepares the bone to match the implant. The component must be stable enough to permit bone ingrowth while avoiding excessive force or damage to the surrounding bone.

Neither method is automatically “stronger,” and cement does not necessarily mean that a replacement is old-fashioned. Cemented fixation provides immediate mechanical stability, while uncemented fixation aims to develop a biological attachment to bone. Both methods can be durable when the implant, patient and technique are appropriately matched.

Questions You May Wish to Ask

You may find it helpful to ask your surgeon:

  • Will my femoral stem and socket be cemented or uncemented?
  • Why is that combination suitable for my bone and circumstances?
  • Does my bone quality increase my risk of fracture?
  • How well established are the proposed implants?
  • Are there reasonable alternative fixation methods in my case?

This article provides general information and does not replace individual clinical advice. Fixation and implant selection should be discussed with your surgical team because the most appropriate choice depends on your individual anatomy, health and bone quality.

References

  1. National Joint Registry. Outcomes after joint replacement, 2003 to 2022. In: 20th Annual Report 2023. National Center for Biotechnology Information.
  2. Griffiths R, White SM, Moppett IK, et al. Safety guideline: reducing the risk from cemented hemiarthroplasty for hip fracture 2015. Anaesthesia. 2015;70(5):623–626. doi: 10.1111/anae.13036.
  3. Deere KC, Whitehouse MR, Porter M, Blom AW, Sayers A. Assessing the non-inferiority of prosthesis constructs used in total and unicondylar knee arthroplasty and total hip arthroplasty using data from the National Joint Registry. BMJ Open. 2019;9. doi: 10.1136/bmjopen-2018-026736.
  4. Perry DC, Metcalfe D, Judge A, et al. The association between implant design, age, sex and the rate of major reoperation in patients undergoing primary total hip replacement: a retrospective study of UK National Joint Registry and Hospital Episode Statistics data. PLoS Med. 2025. PubMed PMID: 41296797.
  5. National Institute for Health and Care Excellence. Total hip replacement and resurfacing arthroplasty for end-stage arthritis of the hip. Technology appraisal guidance TA304. Published 26 February 2014. NICE TA304.

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