Verifying the Effectiveness of the NUsurface® System

The NUsurface® Meniscus Implant is intended for use in patients with medial compartment pain that have had a previous partial medial meniscectomy.

Patients who meet the inclusion/exclusion criteria will be assigned by balanced randomization into one of two groups: the Meniscus Implants versus non-surgical standard of care. The KOOS (Knee injury and Osteoarthritis Outcome Score) and IKDC (International Knee Documentation Committee) forms will be used to provide a comprehensive evaluation of the patients' pre-intervention and post-intervention condition including activity levels, pain, swelling, locking, stability, support, sports activity, and quality of life assessment.

Inclusion criteria

• Had > 6 months ago a medial partial meniscectomy as confirmed by patient history and MRI
• Is between age 30 and 75 years (inclusive) at the time of study treatment
• Has neutral alignment ±5º of the mechanical axis, as measured from the angle formed by a line drawn from the center of the femoral head to the medial tibial spine and a line drawn from the medial tibial spine and the center of the ankle joint
• Has ≥ 2 mm intact medial meniscal rim capable of being fitted with a NUsurface® device AND is also recommended for the baseline non-surgical (and, if likely to receive benefit, any injection) therapies to be administered in the study.
• Is willing to be entered into either arm of the study: implanted with the NUsurface device OR treated with the recommended control arm therapies.
• Is willing and able to attend all follow up visits, complete all study questionnaires, and undergo required X-ray and MRI schedule
• Is able and willing to understand and sign the Informed Consent Form
• Is able to read and understand the English language
• Has a KOOS Pain of ≤ 75 (100 being the highest attainable and no pain)

Exclusion criteria

• Has a symptomatic knee because of a tear that could be addressed by a repeat partial meniscectomy leaving > 4 mm of medial meniscus rim
• Has evidence of a Outerbridge Grade IV cartilage loss on the medial tibial plateau or femoral condyle that potentially could contact a NUsurface implant (e.g., a focal lesion > 0.5 cm2 correlating to a circular defect of > 8 mm in diameter)
• Has complete disruption of the posterior root attachment of the meniscus
• Has lateral compartment pain and Grade III or Grade IV Outerbridge cartilage score in the lateral compartment
• Has a varus or valgus knee deformity > 5º requiring a tibial or femoral osteotomy
• Has a laxity level of more than Grade II (IKDC), primary or secondary to an injury of the anterior cruciate ligament (ACL) and/or posterior cruciate ligament (PCL) and/or lateral collateral ligament (LCL) and/or medial collateral ligament (MCL)
• Has significant trochlear dysplasia, patellar instability or symptomatic patellar misalignment
• Has patellar compartment pain and Grade III or Grade IV Outerbridge cartilage score in the patellar compartment.
• Compared to a normal knee, has obvious radiological evidence of medial femoral squaring, anatomical variance in the medial tibial plateau, or irregularly shaped cartilage surface
• Had an ACL reconstruction performed < 9 months prior to study treatment
• Has a BMI > 32.5 at the time of study treatment
• Decides to receive (if eligible and an option) allograft medial meniscus transplantation
• Received any type of prosthetic knee implant made of artificial non-resorbable plastic, metal or ceramic, not including the NUsurface® Meniscus Implant
• Has a knee flexion contracture > 10º
• Has flexion < 90º
• Had a previous medial femoral condyle surgery (not including microfracture) or High Tibial Osteotomy (HTO)
• Has insufficiency fractures or avascular necrosis of the medial compartment
• Has an active infection or tumor (local or systemic)
• Has any type of knee joint inflammatory disease including Sjogren's syndrome
• Has neuropathic knee osteoarthropathy, also known as Charcot joint
• Has any medical condition that does not allow possible arthroscopy of the knee
• Has neurological deficit (sensory, motor, or reflex)
• Is currently involved in another investigation of the lower extremity
• Anticipates having another lower extremity surgery during the study period
• Is contraindicated for hyaluronic acid injections (i.e., patients with known hypersensitivity [allergy] to hyaluronan [sodium hyaluronate] preparations); patients having knee joint infections or skin diseases or infections in the site of possible injections
• Is contraindicated for corticosteroid injections (i.e., patients with allergy to any of the components or with idiopathic thrombocytopenic purpura)
• Has received any corticosteroid knee injections ≤ 3 months prior to study treatment
• Has chondrocalcinosis
• Is on immunostimulating or immunosuppressing agents
• Has ipsilateral or contralateral lower limb joint conditions that may affect ambulation or KOOS (e.g. have a leg length discrepancy > 2.5 cm [1 inch], causing a noticeable limp)
• Is a female who is lactating, expecting, or is intending to become pregnant during the study period
• Is an active smoker
• Is mentally incapacitated (incapable of appraising or controlling conduct) or have mental disability (e.g., dementia or Alzheimer's)
• Is a prisoner
• Is a patient who has economic incentive not to improve