Knee Replacement Surgery
Let’s explore this topic in the following sections:
Knee prosthesis revision is a major surgical procedure required when a previously implanted knee prosthesis begins to show problems or functions suboptimally. This procedure is essential for various reasons and can significantly improve patients’ quality of life by reducing pain and restoring joint function.
The average lifespan of a knee prosthesis ranges between 10 and 25 years, and thanks to increasingly refined techniques, this duration continues to grow year after year. However, there are several reasons why a prosthesis might fail or require revision. These include prosthetic component wear or loosening from the bone, infections, fractures, new-onset instability, or patient-related factors—such as prior surgeries on the knee, body weight, or activity level. [1–2]
Regardless of the cause, implant failure generally presents the same cluster of symptoms: pain, reduced knee function, swelling, and sometimes increased local temperature.
When experiencing any of these symptoms, it is essential to undergo a specialist consultation to assess whether surgical revision is needed.
During this procedure, the surgeon removes some or all of the previously implanted prosthesis components, replacing them with new ones.
While the goal remains the same as the primary replacement—pain relief and improved function—revision surgery is longer and more complex, requiring careful planning and specific implants to ensure a successful outcome. In the primary procedure, femur, tibia, and patella surfaces are replaced with metal components.
Main Causes of Knee Prosthesis Revision
The main reasons for knee prosthesis revision include aseptic loosening, periprosthetic infections, osteoarthritis progression in unicompartmental prostheses, and prosthesis wear.
Approximately 15–20% of patients are dissatisfied with their knee prosthesis outcomes—sometimes without a clearly identifiable cause, other times due to issues revealed by lab tests or imaging. Infection is a potential complication of any surgery—including total knee replacement—and can occur during hospitalization or even years after the procedure.
Main Risk Factors for Knee Arthroplasty Infection
Knee arthroplasty infection is a serious complication that can severely impair implant function, leading to stiffness and pain. The implant may loosen or remain fixed while symptoms progress, making revision surgery necessary.
Major risk factors include:
- Previous knee surgeries;
- Obesity;
- Diabetes mellitus;
- Renal failure;
- Respiratory failure;
- Immune system disorders;
- Treatment with biological drugs;
- Infections in other parts of the body (e.g., urinary, intestinal, pulmonary, dental).
Periprosthetic Infection or Knee Prosthesis Infection
Infections involving knee prostheses are among the most serious postoperative complications. They may require urgent surgery to remove the implant, debride the area, and start specific antibiotic therapy.
Prompt diagnosis and early treatment are essential for optimal outcomes and to prevent complications. In many cases, it’s not possible to reimplant a new prosthesis immediately.
These situations require a two-stage revision procedure (Fig. 4). [2]
Aseptic Loosening of the Knee Prosthesis
Aseptic loosening affects about 1–2% of knee prosthesis patients. It occurs due to loss of implant adhesion to bone, often from insufficient cement fixation. Treatment is typically surgical and involves single-stage revision to restore stability and function (see Fig. 1).
Knee Prosthesis Revision for Fracture
Fractures near the prosthesis may require revision, especially if they compromise implant stability. This situation requires careful assessment and often a tailored intervention.
A “periprosthetic fracture” refers to a bone injury adjacent to the prosthetic components. These are often caused by falls and usually require revision surgery.
In planning the revision, the surgeon considers the fracture location, component stability, bone quality, and the patient’s general condition. In elderly patients with poor bone quality, large revision implants may be used to replace the fractured bone (Figs. 2 and 3).
Joint Stiffness or Instability
Stiffness and instability can greatly affect joint function and patient wellbeing. Sometimes, revision surgery is necessary to restore mobility and stability.
After total knee replacement, mobility may remain insufficient due to excessive scar tissue around the joint. In such cases, the orthopedic surgeon may perform a “manipulation under anesthesia” to break adhesions and improve motion.
Another common procedure is arthroscopic arthrolysis (removal of adhesions via arthroscopy). If the knee remains stiff or imaging shows malpositioned components, revision surgery may be required.
Worn-Out Knee Prosthesis
As previously mentioned, knee prostheses generally last 15–20 years, depending on use, patient weight, and activity level. Wear—especially of the polyethylene insert—may require revision.
Over time, friction and mechanical load cause component wear, leading to deterioration, pain, and limited motion. The decision to proceed with revision depends on the extent of wear, patient symptoms, and impact on quality of life.
How Is Knee Prosthesis Revision Surgery Performed?
Revision surgery involves removing the old implant, preparing the bone, and inserting a new prosthesis. The procedure is tailored to each patient and may vary significantly in complexity.
This delicate but crucial operation aims to restore joint function and improve quality of life. Accurate diagnosis of implant failure is essential to developing an effective surgical plan. Surgical steps typically include:
- Incision: along the previous scar, extended as needed;
- Evaluation: careful assessment of local conditions;
- Debridement: removal of debris or fibrotic tissue;
- Explantation: removal of the old prosthesis;
- Implantation: insertion of the new prosthesis;
- Reconstruction: filling any bone defects.
Patients typically begin partial weight-bearing 24 hours after surgery and start physiotherapy, which continues for 2–3 months. In some cases, full weight-bearing is delayed by 1–2 months depending on the extent of bone reconstruction.
If the prosthesis fails without infection, a single revision surgery—known as aseptic revision—is usually sufficient. [2]
Long-term outcomes are excellent. Many patients achieve satisfying results within a few months and return to daily activities. However, complete recovery of joint mobility or pain elimination may not always be possible, especially in cases involving infection or major bone loss.
Knee Prosthesis Revision: Prof. Marcheggiani Muccioli’s Background
Prof. Giulio Maria Marcheggiani Muccioli has distinguished himself in orthopedics, graduating with honors in Medicine and Surgery at the University of Bologna in 2006, specializing with honors in Orthopedics and Traumatology at the Rizzoli Orthopedic Institute, and earning a PhD in Surgical Sciences.
He is an Associate Professor of Orthopedics at the University of Bologna’s Faculty of Medicine and Surgery, with a focus on biomechanics and lower/upper limb pathology.
He expanded his expertise through international fellowships in the UK, Japan, and the USA, establishing himself as an orthopedic surgeon with extensive experience, performing over 250 surgeries annually.
He plays a key role in training new generations of doctors through academic teaching in various medical and surgical disciplines.
He is one of only ten Italian surgeons selected in the last 20 years by the American Knee Society for the prestigious John Insall Knee Surgery Fellowship. His contributions include over 250 scientific publications and constant academic and conference involvement, demonstrating his commitment to advancing minimally invasive techniques, sports medicine, and innovations in knee and shoulder treatment.
Bibliography
- High rate of implant loosening for uncemented resurfacing-type medial unicompartmental knee arthroplasty. Bruni D, Zaffagnini S, Iacono F, Bragonzoni L, Lo Presti M, Neri MP, Marcheggiani Muccioli GM, Nitri M, Raspugli G, Marcacci M. Knee Surg Sports Traumatol Arthrosc. 2016 Oct;24(10):3175-3182.
- Sharkey PF, Lichstein PM, Shen C, Tokarski AT, Parvizi J. Why are total knee arthroplasties failing today–has anything changed after 10 years? J Arthroplasty. 2014 Sep;29(9):1774-8. doi: 10.1016/j.arth.2013.07.024. Epub 2014 Jul 5. PMID: 25007726.
- Lombardi AV Jr, Kolich MT, Berend KR, Morris MJ, Crawford DA, Adams JB. Revision of Unicompartmental Knee Arthroplasty to Total Knee Arthroplasty: Is It as Good as a Primary Result? J Arthroplasty. 2018 Jul;33(7S):S105-S108.
- The adductor tubercle as an important landmark to determine the joint line level in total knee arthroplasty: from radiographs to surgical theatre. Iacono F, Raspugli GF, Bruni D, Filardo G, Zaffagnini S, Luetzow WF, Lo Presti M, Akkawi I, Marcheggiani Muccioli GM, Marcacci M. Knee Surg Sports Traumatol Arthrosc. 2014 Dec;22(12):3034-8.
- Lei PF, Hu RY, Hu YH. Bone Defects in Revision Total Knee Arthroplasty and Management. Orthop Surg. 2019 Feb;11(1):15-24.
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