Scorpio Posterior Stabilised (PS) vs Scorpio NRG ("Energize") PS - Total Knee Arthroplasty

Scorpio PS vs Scorpio NRG PS - Total Knee Arthroplasty Comparative Investigation of Function

Single-centre, prospective, randomized comparative study to compare the maximum flexion and Chair Raise achievement ratios of the Scorpio PS and and the Scorpio NRG PS. Documentation of all complications.

Surveillance design: Single-centre, prospective, randomized comparative study. Objectives: To compare the maximum flexion (active and passive) and Chair Raise achievement ratios. All complications will be documented.

Number of subjects to be enrolled: All consecutive Scorpio patients are included until a group size of 88 is reached.

Clinical evaluations: Chair raise test, Stair climb test, Western Ontario McMaster Osteoarthritis Index (WOMAC) patient self evaluation, EuroQuol - 5 dimension (EQ-5D) patient questionnaire. Standard clinical, functional and pain parameters (Knee Society Score), pre-operatively and post-operatively. All per- and post-op complications.

Inclusion Criteria:

• Patients requiring a primary total knee arthroplasty (TKA)
• Male and nonpregnant female patients
• Between 18 and 80 years of age at time of surgery
• Patients with a diagnosis of osteoarthritis (OA), avascular necrosis (AVN), and not severe posttraumatic arthritis
• No previous osteosynthesis of the involved knee during the last 12 months
• Patients who understand the conditions of the study and are wiling to participate for the length of the described follow up
• Patients who are capable of, and have given, informed consent for participation in the study

Exclusion Criteria:

• Patients requiring revision surgery of a previous implanted total knee system
• Patients with a diagnosis of severe posttraumatic arthritis (TA) and rheumatoid arthritis (RA)
• Patients with active infection
• Patients with malignancy
• Patients with an immobile hip or ankle arthrodesis
• Severe obese patients (BMI > 35)
• Patients with a neurological deficit
• Previous history of unicompartmental knee arthroplasty or patellar prosthesis
• Patients with concurrent illnesses which are likely to affect their outcome