Primary THA Using Thin Polyethylene Liners and Large Femoral Heads: A Minimum 5-Year Follow-Up.

BACKGROUND: Large femoral head sizes are commonly used in total hip arthroplasty (THA) to minimize the risk of instability. With small acetabular cup-size, large femoral head diameter often results in the use of thin polyethylene liners. The purpose of this study was to evaluate clinical and radiographic results of large femoral heads against thin polyethylene liners with minimum 5-year follow-up. METHODS: This was a retrospective review identifying 58 primary THAs utilizing thin polyethylene inserts from one manufacturer (X3 polyethylene, Stryker, Mahwah, NJ) and large femoral heads (36 mm or greater) with minimum 5-year follow-up. A total of 3 patients were deceased and 11 lost to follow-up, leaving 44 patients for review. All patients were female with mean age 65.7 (range 26-85) and mean body mass index (BMI) 29.9 (range 19.6-45.4). Average length of follow-up was 8.5 years (range 5.1-11.3). Outcome measures included survivorship, complications, PROMs and radiographic analysis. RESULTS: There were four revisions: two aseptic loosening, one prosthetic joint infection, and one recurrent dislocation. Average HOOS-Jr, FJS-12, and patient satisfaction using Likert score was 94.3/100, 92.9/100, and 4.69/5.00, respectively, with 94% of patients reporting being satisfied or very satisfied. Radiographic analysis at average of 8.5 years demonstrated well-fixed implants without evidence of progressive radiolucent lines, osteolysis, or failure of the polyethylene liner. Survivorship using failure of the thin polyethylene liner as the endpoint was 100% at an average of 8.5 years. CONCLUSION: Thin polyethylene liners used with large femoral head sizes in small acetabular cups demonstrated excellent results at average 8.5-year follow-up with no cases of liner fracture or osteolysis.

Playground Safety is Associated With Playground, Park, and Neighborhood Characteristics.

BACKGROUND: More than 200,000 children each year are treated at emergency departments for injuries occurring on playgrounds. Empirically derived data are needed to elucidate factors associated with playground safety and reduce injury rates. OBJECTIVE: Determine if neighborhood, park and playground characteristics are significantly associated with playground safety. METHODS: A 24-item report card developed by the National Program for Playground Safety was used to assess playground safety at 41 public parks in a small to midsized, Midwestern city. Trained assessors evaluated the parks and playgrounds in June/July and used a standardized method to count the numbers of users. Data from the 2010 U.S. Census were used to describe the neighborhoods surrounding the parks. RESULTS: The average safety score for all playgrounds was 77.4% which denotes acceptable safety levels. However, 17.1% of the playgrounds were potentially hazardous and in need of corrective measures. Playgrounds were safer in neighborhoods with more youth (< 18 years of age) and educated adults and in parks with better quality features. Playgrounds with fewer amenities were relatively less safe. CONCLUSIONS: Park safety levels need to be improved to reduce the risk of physical injuries. Future studies examining cause-effect associations between environmental features and playground safety are warranted.