Does the Use of Patient Specific Instrumentation Improve Outcomes in Knee Arthroplasty Surgery for Osteoarthritis When Compared to Standard Posterior Referenced Instrumentation?

Total Knee Arthroplasty Inserted With Patient Specific or Standard Instruments

The goal of this randomized study is to see if using patient-specific instruments (PSI) during total knee replacement surgery improves outcomes compared to standard instruments. The study focuses on adults with knee osteoarthritis who need knee replacement surgery. Specifically, it aims to answer the following questions:

Does using PSI improve knee function and stability as experienced by the patient? Does PSI lead to more normal knee motion during bending and straightening? Does PSI result in at least as good tibial (shin bone) component fixation as standard instruments? Is PSI more cost-effective than standard instruments? Researchers will compare PSI with standard instruments in 70 patients. Half will receive knee replacement surgery using PSI, and the other half with standard instruments. Patients will be randomly assigned to each group.

Participants will:

Undergo knee replacement surgery with either PSI or standard instruments. Have a series of follow-ups, including assessments of knee function, satisfaction, and alignment of the knee implant, conducted before surgery and at 3 months, 1 year, 2 years, and 5 years after surgery.

The study will include patients aged 40-75 with primary osteoarthritis, a body mass index (BMI) below 35, and no other major medical conditions that could impact surgery. Patients will also need to be willing to undergo necessary imaging, such as magnetic resonance imageing (MRI) scans and standing X-rays.

Outcomes will be measured using various assessment tools, including the Oxford Knee Score, Knee Society Score, and a patient satisfaction survey. Researchers will also record surgery details, such as operating time, blood loss, and knee implant size. Imaging methods, including MRI, computed tomgraphy (CT) scans, and specialized X-rays, will be used to evaluate knee alignment and stability over time.

The results of this study are expected to provide insights into whether patient-specific instruments offer clinical or economic advantages over traditional tools in knee replacement surgery.

Inclusion Criteria:

• Medial or lateral primary osteoarthritis (OA) Ahlbäck Grade 2-4
• Varus or valgus deformity ≤10 degrees, extension defect ≤10 degrees
• Age 40-75 years
• BMI <35
• American Society of Anesthesiologists (ASA) score 1-3.
• Coming from independent living in own home
• Able and willing to undergo MRI scan (for custom patients), full-leg standing radiographs and follow up with RSA
• Written informed consent.

Exclusion Criteria:

• Cortisone treatment during the last 6 months before operation
• Neurological diseases with symptoms, stroke with sequel
• Endocrine diseases with symptoms
• OA secondary to trauma, infection, inflammatory disease or congenital and acquired deformities
• BMI >=35
• OA of the hip with symptoms
• Ongoing infection
• Any metal within 150 mm from the joint line on the side to become operated
• Unable or unwilling to participate in the follow-up.