LFIT™ Anatomic CoCr Femoral Heads With X3® Polyethylene Insert Study

Linear wear rate is defined as the annual rate of removal of the polyethylene from the X3 polyethylene insert mated with LFIT™ Anatomic CoCr Femoral Heads determined by comparing digitized images of serial radiographs obtained over the follow-up period.

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The change in HHS is reported by comparing the mean preoperative, 1, 3, and 5 year scores. The HHS assesses pain, function, joint deformity and range of motion. Scores can range from 0 to 100 with 0 being the worst and 100 being the best score. A score of 80-100 is considered good-excellent and a score of less than or equal to 79 is considered fair-poor.

90-100 = excellent 80-89 = good 70-79 = fair 0-69 = poor

This subscore of the overall HHS provides the patient with 6 possible answers to choose from ranging from, no pain/ignores it, to totally disabled/crippled/pain in bed/bedridden. A maximum of 44 points is possible for this subscore indicating no pain/ignores it.

Pain:

• None or ignores it = 44 points
• Slight, occasional, no compromise in activities = 40 points
• Mild pain, no effect on average activities, rarely moderate pain with unusual activity, may take aspirin = 30 points
• Moderate pain, tolerable but makes concessions to pain. Some limitation of ordinary activity or work. May require occasional pain medicine stronger than aspirin = 20 points
• Marked pain, serious limitation of activities = 10 points
• Totally disabled, crippled, pain in bed, bedridden = 0 points

This subscore of the overall HHS includes the total points awarded for five different ranges of motion (flexion, abduction, external rotation, internal rotation, adduction). Subscore range is minimum of 0 to maximum of 5 points; the higher the value, the better the outcome.

Flexion:

0-45 degrees x 1.0 index value = max 45 points

45-90 degrees x 0.6 index = max 27 points

90-110 degrees x 0.3 index = max 6 points

110-130 degrees = max 0 points

Abduction:

0-15 degrees x 0.8 index = max 12 points

15-20 degrees x 0.3 index = max 1.5 points

20-45 degrees x 0 index = max 0 points

External Rotation in extension:

0-15 degrees x 0.4 index = max 6 points

Over 15 degrees = max 0 points

Internal Rotation in extension:

Any = max 0 points

Adduction:

0-15 degrees x 0.2 index = max 3 points

Over 15 degrees - max 0 points

To determine the over-all rating for range of motion, multiply the sum of the index values x 0.05.

The change in SF-12 is reported by comparing the mean preoperative, 1, 3, and 5 year scores. The SF-12 Health Survey is a 12 item patient completed questionnaire to measure general health and well-being. It includes a physical component score and mental status component score; each ranging from 0-100. Low values represent a poor health state and high values represent a good health state.

The change in LEAS is reported by comparing the mean pre-operative, 1,3,and 5 year scores. The LEAS completed by the participant to assess activity level. Activity levels were ordered in terms of intensity from 1 to 18, with 18 indicating the highest activity level.

The number of hips that experienced a hip dislocation.

Radiographic instability is defined as having any of the following findings on x-ray:

• Radiographic indication of progressive radiolucent lines ≥ 2 mm in thickness around the entire acetabular component
• Radiographic indication of migration of ≥ 3 mm or ≥ 5° of the acetabular component
• Radiographic indication of progressive radiolucent lines ≥ 2 mm thickness around the entire femoral component
• Radiographic indication of progressive subsidence of the femoral component of ≥ 5 mm.

A revision is defined as surgical removal and replacement of the femoral bearing head or femoral stem components, or the acetabular shell or acetabular polyethylene liner.

The 97.42% estimate is obtained by Kaplan-Meier method.