Pittsburgh, PA, United States
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Kurtz S.M.,Exponent, Inc. | Kurtz S.M.,Drexel University | Ong K.L.,Exponent, Inc. | Lau E.,Exponent, Inc. | And 2 more authors.
ASTM Special Technical Publication | Year: 2013

The purpose of this study was to describe actual usage patterns for metal-on-metal (MOM) bearings in the United States using a nationally representative database. The 2005-2009 nationwide inpatient sample (NIS), in combination with the 2009-2010 state inpatient databases (SIDs), was employed to identify primary total hip arthroplasty (THA), revision THA, and resurfacing hip arthroplasty (RHA) patients implanted with a MOM bearing using ICD-9-CM codes. The MOM patient population was characterized by gender, age, race, U.S. Census region, hospital characteristics, and insurance coverage. The prevalence of MOM bearing usage was estimated between 2000 and 2010. Between 2005 and 2010, MOM bearing usage in the United States ranged between from 32 % and 40 % of primary THAs and from 26 % and 32 % of revision THAs. Utilization of MOM bearing types in primary/revision THA and RHA peaked in 2008. By 2010, 755000 patients were estimated to be implanted with MOM bearings in the United States between 2000 and 2010, we estimated that 83.7 % of MOM bearings in the United States were implanted during primary THA procedures, 11.7 % during revision THA, and the remaining 4.6 % during RHA. Our research demonstrates that the prevalence of MOM increased substantially up to a high water mark in 2008. Despite uncertain indications for use, MOM bearings were used extensively in female and elderly patients. Copyright © 2013 by ASTM International.


Hoshino Y.,University of Pittsburgh | Wang J.H.,Sungkyunkwan University | Lorenz S.,TU Munich | Fu F.H.,University of Pittsburgh | And 2 more authors.
Knee Surgery, Sports Traumatology, Arthroscopy | Year: 2012

Purpose: The variation of distal femur morphology has been often reported, especially in relation to ACL injury. However, it remains unknown how morphological differences affect knee kinematics and ACL function. The location of the transcondylar axis, a common anatomical reference line, may be a significant aspect of morphological variation. It was hypothesized that the location of this axis would be different between genders, and between ACL-injured and non-injured subjects. Methods: 3D CT scans of contralateral healthy femurs in 38 unilateral soft tissue injured patients (20 men/18 women, 26 ACL injury/12 non-ACL injury (7 with PCL injuries and 5 with medial meniscus root tears)) were analyzed three-dimensionally. Condyle offset was calculated as the distance between the transcondylar axis and the anatomical axis of the femur. Condyle offset ratio (COR) was then calculated by dividing the condyle offset by the condyle radius. Gender and ACL-injured and non-injured group differences were assessed. Results: Larger COR was found in women, 1.10 ± 0.14, than men, 0.96 ± 0.08. In women, the ACL-injured group had significantly larger COR than the non-ACL injury group, but no difference was found in men. Conclusion: COR is a unique morphological feature which is measureable from 3D CT. COR is larger in women, and could be a possible risk indicator for ACL injury in the female population. Level of evidence: III. © 2011 Springer-Verlag.

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