The SUN Clinical Trial (Safety Utilizing NUsurface Meniscus Implant)

Inclusion Criteria:

1. Had > 6 months ago a medial partial meniscectomy as confirmed by patient history and
MRI

2. Has a KOOS Pain of ≤ 75 (100 being the highest attainable and no pain)

3. Is between age 30 and 75 years (inclusive) at the time of study treatment

4. 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

5. Has ≥ 2 mm intact medial meniscal rim capable of being fitted with a NUsurface®
device

6. Is able to do the study required follow-up visits, questionnaires, X-rays and MRI's

7. Is able to read and understand the English language if treated at a U.S. site or read
and understand one of the official country languages if treated at a site Outside the
U.S.

8. Is able and willing to understand and sign the Informed Consent Form

Exclusion Criteria:

1. Has a symptomatic knee because of a tear that could be addressed by a repeat partial
meniscectomy leaving > 4 mm of medial meniscus rim

2. 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)

3. Has complete disruption of the posterior root attachment of the meniscus

4. Has lateral compartment pain and Grade III or Grade IV Outerbridge cartilage score in
the lateral compartment

5. Has a varus or valgus knee deformity > 5º requiring a tibial or femoral osteotomy

6. 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)

7. Has significant trochlear dysplasia, patellar instability or symptomatic patellar
misalignment

8. Has patellar compartment pain and Grade III or Grade IV Outerbridge cartilage score
in the patellar compartment.

9. 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

10. Had an ACL reconstruction performed < 9 months prior to study treatment

11. Has a BMI > 32.5 at the start of study treatment

12. Decides to receive (if eligible and an option) allograft medial meniscus
transplantation

13. Received any type of prosthetic knee implant made of artificial non-resorbable
plastic, metal or ceramic, not including the NUsurface® Meniscus Implant

14. Has a knee flexion contracture > 10º

15. Has flexion < 90º

16. Had a previous medial femoral condyle surgery (not including microfracture) or High
Tibial Osteotomy (HTO)

17. Has insufficiency fractures or avascular necrosis of the medial compartment

18. Has an active infection or tumor (local or systemic)

19. Has any type of knee joint inflammatory disease including Sjogren's syndrome

20. Has neuropathic knee osteoarthropathy, also known as Charcot joint

21. Has any medical condition that does not allow possible arthroscopy of the knee

22. Has neurological deficit (sensory, motor, or reflex)

23. Is currently involved in another investigation of the lower extremity

24. Anticipates having another lower extremity surgery during the study period

25. Is contraindicated for hyaluronic acid injections (i.e., patients with known
hypersensitivity [allergy] to hyaluronan [sodium hyaluoronate] preparations);
patients having knee joint infections or skin diseases or infections in the site of
possible injections

26. Is contraindicated for corticosteroid injections (i.e., patients with allergy to any
of the components or with idiopathic thrombocytopenic purpura)

27. Has received any corticosteroid knee injections ≤ 3 months prior to study treatment

28. Has chondrocalcinosis

29. Is on immunostimulating or immunosuppressing agents

30. 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)

31. Is a female who is lactating, expecting, or is intending to become pregnant during
the study period

32. Is an active smoker

33. Is mentally incapacitated (incapable of appraising or controlling conduct) or have
mental disability (e.g., dementia or Alzheimer's)

34. Is a prisoner

35. Is a patient who has economic incentive not to improve

36. Certain patient populations that are at high risk for poor healing or outcomes such
as patients who have a co-morbidity that reduces life expectancy to less than 36
months

37. Patients who are contraindicated for MRI (i.e., pacemaker, defibrillator, cochlear
implants, etc.)