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.

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.