Osteoarthritis (OA) of the Knee, Primary Osteoarthritis Patients Scheduled for Total Knee Replacement Surgery
Conditions
Keywords
Patient Specific Instrumentation, Total Knee Arthroplasty, Zimmer PSI, NexGen, Materialise
Brief summary
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.
Interventions
DEVICEPatient specific instrumentation (PSI)
Cutting guides that are manufactured using advanced imaging and modelling techniques to create instruments that align more closely with the unique anatomy of each patient. Custom guides were created based on a preoperative MRI protocol (Zimmer Patient Specific Instrumentation for NexGen® Complete Knee Solution, Zimmer Biomet, Warsaw, Indiana, United States in collaboration with Materialise NV, Leuven, Belgium) to optimize the placement of the components without the need for intramedullary alignment.
DEVICEConventional instruments
Instruments specific to the implant that are used to guide bone cutting in reference to the intramedullary canal or using an extramedullary jig.
PROCEDURECemented Total Knee Arthroplasty
A cemented TKA (NexGen® Complete Knee Solution, Zimmer Biomet, Warsaw, Indiana, United States) is used in all cases with a cruciate retaining (CR) or posterior stabilized (LPS) prosthesis as determined by the surgeon.
Sponsors
Zimmer Biomet
Ingabritt och Arne Lundbergs Forskningsstiftelse
Vastra Gotaland Region
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
40 Years to 75 Years
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Oxford Knee Score (OKS) | Prior to and 2 years post surgery | A instrument validated for use in Sweden for measuring patient reported functional outcomes following knee arthroplasty. The OKS is widely used due to its reliability and sensitivity to clinically meaningful improvements in knee function after TKA. The score ranges from 12-48 points with a minimal important change of 8 and a ceiling reported to be around 44-48 points. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Knee Society Knee Score (KSKS) | Prior to and up to 5 years post surgery | A clinician-rated tool that evaluates knee stability and function in activities of daily living. The KSKS is divided into two parts, Knee and Function, each with a max score of 100 points. The minimal clinically important difference of the KSKS is reported to be around 4-10 points for each individual part and a 39-40 increase is considered a substantial clinical improvement. |
| Oxford Knee Score (OKS) | Prior to and up to 5 years post surgery | See primary outcome measure. |
| EuroQol EQ-5D-3L | Prior to and up to 5 years post surgery | A generic health status measure that allows for the comparison of TKA outcomes across different populations and facilitates cost-effectiveness analyses based on quality-adjusted life years (QALYs). The instrument contains a set of questions reported on a Likert scale which is then converted to a total between 0 and 1 using a value set. The minimal clinically important difference has been reported at 0.0085. |
| Radiographic evaluation | Postoperatively, up to three months postop. | Conventional imaging in the anteroposterior (AP) and lateral views, along with full-leg standing radiographs and CT-scan. These images will be used to assess postoperative alignment and the positioning of TKA components in three planes-coronal, sagittal, and axial (rotational). |
| Radiographic evaluation, radiolucent lines | Up to 5 years post surgery | Areas of decreased density (radiolucency) between the bone and cement interface. These are monitored as a potential indicator of loosening or poor fixation. |
| Radiostereometric Analysis (RSA) | Up to 5 years post surgery | Used to quantify implant migration as a surrogate marker for fixation stability. Radiologically measures the migration of tantalum markers inserted in the bone in reference to the metal implants. |
| Pain and Patient Satisfaction Visual Analogue Scales (VAS) | (Prior to) and up to 5 years post surgery | Provides additional patient-centred measures of perceived pain relief and satisfaction with the procedure. The scores are reported on a 0-5 and 0-100 scale. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Number of patients undergoing revision surgery | Up to 5 years post surgery | Will be reported as descriptive elements. |
Countries
Sweden
Outcome results
None listed