This study will compare the clinical outcomes for patients undergoing a total knee replacement using a bipolar sealer, the Aquamantys® System, as compared to standard electrocautery. Total blood loss during the hospital stay and knee mobility and discharge factors will be analyzed.

Inclusion Criteria:

• Patient is ≥18 years of age
• Patient has failed conservative therapy of osteoarthritis of the knee and has been listed to undergo primary TKA
• Patient is willing and able to provide written informed consent.
• Pre-assessment Haemoglobin ≥ 11.0g/dl
• Patient is suitable to receive spinal anaesthesia with no peripheral nerve blocks
• Patients willing to undergo blood transfusion

Exclusion Criteria:

• Patients that are listed for unicondylar or revision TKA
• Patients who are being converted from a previous high tibial osteotomy and a previous unicondylar knee arthroplasty
• Fixed motor deficit thus affecting functional assessment of the knee
• Patients presenting with a non-osteoarthritis degenerative knee diagnosis
• Patients presenting with known contralateral knee osteoarthritis requiring simultaneous bilateral TKA
• Patients presenting with a history of previous knee infection
• Patients presenting with a pre-operative knee range of motion < 85°
• Knee deformity greater than 20 degrees varus or valgus
• Patients presenting with a history of bleeding disorders and/or are on chronic blood anticoagulation therapy
• Patients with significantly impaired renal function (defined by EGFR >30)
• Patients with allergy or sensitivity to non-steroidal anti-inflammatory drugs, ropivacaine, ketoprofen or adrenaline
• Patients presenting with an internal cardiac defibrillator
• Women who are pregnant
• Evidence of active (systemic or local) infection at time of surgery
• Patients who have habitual opioid use
• Patients who have a psychiatric or mental illness which could impair the consent process or ability to complete patient-report questionnaires
• Morbid obesity [BMI > 40]
• Patients who are unwilling to undergo blood transfusion, if necessary
• Patients who are receiving any implant used in conjunction with a customised-cutting block system
• Any patient who cannot or will not provide written informed consent for participation in the study
• Those whose prospects for a recovery to independent mobility would be compromised by known coexistent, medical problems