Evaluation of 5-year Survival and Clinical Outcomes in Patients Undergoing Total Knee Arthroplasty With a Polyethylene Tibial Component (ALLPOLY-TKA)

Total knee arthroplasty (TKA) is one of the most successful procedures in orthopedic surgery for treating advanced knee osteoarthritis, providing pain relief, functional recovery, and improved quality of life. Advances in implant design and materials have further enhanced joint kinematics and patient satisfaction.

An aging population has increased the number of elderly patients with comorbidities, potentially affecting surgical outcomes and implant longevity. Polyethylene has long been used in knee prostheses; early all-polyethylene tibial components were abandoned due to high wear and failure rates, in favor of metal-backed designs, which became the gold standard.

Recently, highly cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) has renewed interest in all-polyethylene tibial components, although their use remains limited. These implants offer potential advantages, including elimination of locking mechanism failures, reduced backside wear, lower costs, and possibly better load distribution.

Evidence from registries, systematic reviews, and meta-analyses shows that 15-year survival of all-polyethylene tibial components is comparable or even superior to metal-backed designs, with no significant differences in clinical-functional outcomes. Additionally, all-poly components are significantly less expensive.

Given these findings, increasing their use and evaluating outcomes in Italy is warranted. The aim of the present study is to assess implant survival of the Link Symphoknee prosthesis with an all-polyethylene tibial component, along with clinical-functional outcomes and post-discharge readmission rates in patients treated at the Rizzoli Orthopaedic Institute.

Study Overview

• Status: Not yet recruiting
• Conditions: Arthropathy of Knee; Prosthesis Survival
• Intervention / Treatment: Device: Total knee arthroplasty

• Study Type: Interventional
• Enrollment (Estimated): 78
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: stefano zaffagnini; Phone Number: 0516366075; Email: stefano.zaffagnini@unibo.it

Study Locations

• Italy
  • Bologna, Italy, 40136
    • IRCCS Rizzoli Orthopedic Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Male and female subjects aged ≥50 and ≤85 years who are candidates for primary cemented total knee arthroplasty based on physical examination and medical history, including a diagnosis of severe knee pain and disability due to at least one of the following conditions:

   1. Primary or secondary osteoarthritis
   2. Collagen disorders and/or avascular necrosis of the femoral condyle
   3. Moderate valgus, varus, or flexion deformities (Hip-Knee-Ankle angle within ±15°).
2. Patients who provide consent and are able to complete the scheduled study procedures and follow-up assessments.
3. Patients who sign the informed consent approved by the Ethics Committee.

Exclusion Criteria:

1. Patients under 50 years of age and over 85 years of age;
2. Diagnosis of rheumatoid arthritis;
3. Patients with a contralateral joint prosthesis on the same side;
4. Coronal plane deformity with a Hip-Knee-Ankle (HKA) angle greater than 15 degrees in varus or valgus.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: TKA; Implantation of the Link Symphoknee prosthesis with an all-polyethylene tibial component.	Device: Total knee arthroplasty; Implantation of the Link Symphoknee prosthesis with an all-polyethylene tibial component

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Implant failure	It is defined as revision of the prosthesis for any reason-septic, aseptic, or traumatic.	Up to 5 years post-surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Knee injury and Osteoarthritis Outcome Score (KOOS)	It is a subjective score consisting of 42 questions divided into 5 main domains. These domains assess different aspects of symptoms and daily activities, as well as knee-related quality of life.	Up to 5 years post-surgery
Forgotten Joint Score (FJS)	The Forgotten Joint Score (FJS-12) is a patient-reported outcome measure consisting of 12 questions that assesses how frequently a patient forgets they have a joint prosthesis during daily activities. It measures the patient's perception of the artificial joint rather than pain or function alone, with higher scores (0-100) indicating better "forgetting" of the joint	Up to 5 years post-surgery
Visual Analog Scale (VAS) pain	A 10-point unidimensional visual analog scale (VAS) for pain assessment, consisting of a 10 cm horizontal line ranging from "no pain" (0) to "worst imaginable pain" (10). The patient marks their perceived pain intensity on the line, and the distance from zero is measured to quantify pain. It is also used pre- and post-operatively to assess lateral knee pain; a score >2 is considered the presence of lateral compartment pain, while ≤2 indicates its absence	Up to 5 years post-surgery
VAS Satisfaction	Intraoperative and postoperative complications will be recorded. Any hospital readmissions within 90 days of discharge after the arthroplasty procedure will also be documented	Up to 5 years post-surgery
Hip-Knee-Ankle angle (HKA)	It is the angle that measures the mechanical alignment of the lower limb, drawn between the hip, knee, and ankle axes on a weight-bearing radiograph. It is used to assess whether the leg is neutrally aligned or shows varus or valgus deformity	Up to 5 years post-surgery

Collaborators and Investigators

• Sponsor: Istituto Ortopedico Rizzoli

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): October 1, 2032
• Study Completion (Estimated): October 1, 2032

Study Registration Dates

• First Submitted: April 15, 2026
• First Submitted That Met QC Criteria: April 15, 2026
• First Posted (Actual): April 22, 2026

Study Record Updates

• Last Update Posted (Actual): April 22, 2026
• Last Update Submitted That Met QC Criteria: April 15, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Prosthesis Failure; Surgical Procedures, Operative; Arthroplasty, Replacement; Arthroplasty; Orthopedic Procedures; Plastic Surgery Procedures; Prosthesis Implantation; Arthroplasty, Replacement, Knee
• Other Study ID Numbers: ALLPOLY-TKA

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No