LEGION Hinge Safety and Efficacy Study

The objective of this study is to demonstrate statistically significant improvements in the
original Knee Society Clinical Score (KSCS) from baseline to 1 and 2 years in subjects using
the LEGION™ Hinge Knee System. The focus of the 1 and 2 year analyses will be on safety and
efficacy. The 5 year analysis will focus on survivorship and safety.

Inclusion Criteria:

- Subject has gross knee instability resulting from loss of collateral ligament
function, gross bone loss, comminuted fractures of the proximal tibia or distal femur,
rheumatoid arthritis, post-traumatic arthritis, osteoarthritis, degenerative
arthritis, failed osteotomies, unicompartmental replacement or total knee replacement,
or absent or incompetent posterior cruciate ligament and one or both of the collateral
ligaments

- Subject has a failed primary or revision knee replacement

- Subject is 18-80 years of age

- Subject is skeletally mature in Investigator's judgment i.e., subject is not actively
growing or does not have immature bones for any reason

- Subject has met an acceptable preoperative medical clearance and is free of or treated
for cardiac, pulmonary, hematological, infection or other conditions that would pose
excessive operative risk

- Subject is willing to sign and date an IRB/EC-approved consent form

- Subject plans to be available through the five (5) year postoperative follow-up

- If of child bearing potential, Subject reports she is not pregnant nor plans to become
pregnant during the study

- Subject agrees to follow the study protocol

Exclusion Criteria:

- Subject is receiving the study device as a primary knee replacement

- Subject has presence of malignant tumor, metastatic, or neoplastic disease

- Subject is not expected to return to normal ambulatory function (i.e., morbid obesity
or other limiting co-morbidities)

- Subject is pregnant or plans to become pregnant during the course of the study

- Subject has conditions that may interfere with the revision arthroplasty survival or
outcome (i.e., Paget's or Charcot-Marie-Tooth disease, vascular insufficiency,
muscular atrophy, uncontrolled diabetes, moderate to severe renal insufficiency or
neuromuscular disease)

- Subject has known (Subject reported) metal hypersensitivity

- Subject has an emotional or neurological condition that would pre-empt their ability
or willingness to participate in this study

- Subject has BMI>45

- Subject is participating in any other pharmaceutical, biologic, or medical device
clinical investigation or has been treated with an investigational product in the past
30 days

- Subject is facing current or impending incarceration

- Subject is not a good candidate for the study based on Investigator opinion