Uniglide™ Mobile Bearing Unicondylar Knee System vs the Uniglide™ Fixed Bearing Unicondylar Knee System

Arthritic knees are the most common cause of long-term disability resulting in decreased
mobility and increased pain. After other treatments for pain relief and return to
activities of daily living fail, knee joint replacement is often the best option and
unicompartmental knee arthroplasty was introduced as an appropriate treatment for management
of osteoarthritis when disease effects only a portion of the knee joint. This study is a
prospective, comparative, randomized, double blind (patient and post-operative evaluator),
multi-center clinical study under a common protocol to determine the safety and
effectiveness of the Uniglide Unicondylar Mobile Bearing knee implant system.

Inclusion Criteria:

- skeletally mature

- need to obtain pain relief and improved function

- moderate or severe pain with either walking or at rest on the Hospital for Special
Surgery Score

- preoperative medial tibiofemoral joint space narrowing on x-rays (Kellgren Lawrence
grade 3 or 4)

- preoperative Hospital for Special Surgery Knee Evaluation total score of < 69

- preoperative arc of motion of > 90o in the affected knee

- diagnosed with osteoarthritis in the medial compartment of the knee and non-surgical
treatment options have failed to provide relief for symptoms

- able to understand this clinical trial, co-operate with study procedures, and are
willing to return to the clinic, and/or hospital for all the required post-operative
follow-ups

- able to give and have given voluntary, written informed patient consent to
participate in this clinical investigation and have provided Authorization for
Release of Personal Health Information (HIPAA) for the purpose of this clinical study

- willing to be randomized with either of the devices used in the clinical trial as
determined by the randomization schedule

Exclusion Criteria:

- neurological disorders which may interfere or adversely affect gait or weight bearing
(e.g., muscular dystrophy, multiple sclerosis)

- a nutritional problem (protein, calorie, or vitamin/mineral deficiency) that may
impair wound healing mechanisms

- a diagnosed systemic disease that would affect their welfare or the overall outcome
of study (i.e. Paget's disease, renal osteodystrophy)

- immunologically suppressed

- on chronic corticosteroid or non-steroidal anti-inflammatory therapy

- with Charcot's disease

- with metabolic disorders (e.g. osteomalacia), which may impair bone formation

- with distant foci of infections, which may spread to the implant site

- have presence of vascular insufficiency, muscular atrophy and neuromuscular disease

- have diagnosed osteoporosis as evidenced on a DEXA scan (within the last 12 months)

- ave diagnosed rheumatoid arthritis or other forms of inflammatory joint disease

- have diagnosed avascular necrosis

- with malunion, arthrodesis or severe dysplasia in the affected limb

- with rapid joint destruction, marked bone loss or bone resorption in the affected
knee apparent on x-ray

- have incomplete or deficient soft tissue surrounding the affected knee

- have infection, sepsis or osteomyelitis in the affected knee

- have had revision of previously failed prosthesis, failed upper tibial osteotomy or
post traumatic arthritis after tibial plateau fracture in the affected knee

- with a fixed varus deformity (not passively correctable) of greater than 15 degrees
and a flexion deformity greater than 15 degrees in the affected knee

- with insufficient collateral, anterior or posterior cruciate ligaments in the
affected knee, which would preclude stability of the device

- with disease or damage to the lateral compartment of the affected knee (Outerbridge
classification II, III, or IV)

- with a Body Mass Index > 36

- with a sensitivity to device material

- Females who are pregnant

- prisoners,known drug or alcohol abuser, smoker, or have a psychological disorder

- Based upon intra-operative assessment, cartilage and bone erosions involving more
than the anterior and middle parts of the medial compartment. The posterior part of
the medial compartment and the lateral compartment having cartilage of less than
normal thickness. (as assessed using the Outerbridge Classification system).