Thomas J. Blumenfeld

Hip fractures in the United States: 2008 nationwide emergency department sample

To evaluate the recent epidemiology of hip fractures in the US.

Fracture of a cross-linked polyethylene liner: a multifactorial issue.

A limited number of reports have detailed the cause of fracture of a highly cross-linked polyethylene liner. Typically, the fractures have occurred in a region of thin and/or unsupported polyethylene, in association with superiorly directed edge loading conditions secondary to an excessively inclinated acetabular component. This case report details an unusual fracture mechanism of a 5-mrad cross-linked liner caused by horizontal loading conditions. The report details several factors that were felt to be etiologic including the specific liner locking mechanism. The treatment options are discussed.

Midterm Results of Delta Ceramic-on-Ceramic Total Hip Arthroplasty

This study reports mid-term results of Delta ceramic on ceramic (COC) in total hip arthroplasty (THA). Subjects received Delta COC THA in a prospective multi-center study with either 28 mm (n=177) or 36 mm (n=168) articulations. Annual clinical and radiographic evaluations were performed, and patients were asked about hip noises. At mean 5.3-year follow-up there were 3 (0.9%) post-operative liner fractures. Nine revisions were performed (2 liner fracture, 4 stem loosening, 3 deep infection). Kaplan-Meier survivorship at 6 years was 96.9% (94.0-98.4). Twenty-six (7.5%) subjects reported squeaking, of whom none were revised. One (0.3%) subject could reproduce a sound in clinic. More patients reported squeaking with a 36 mm bearing (28 mm: 7/177, 36 mm: 19/168, P=0.013).

Implant choices, technique, and results in revision acetabular surgery: a review.

Acetabular reconstruction in revision total hip arthroplasty can successfully be achieved with hemispherical components featuring a porous or roughened ingrowth surface and options for placement of multiple screws. Most defects can be reconstructed with large hemispherical or “jumbo” cups. Achieving component stability and sufficient contact area on adequate host bone is mandatory. Defects with greater bony loss or compromised columns require either the use of modular augments combined with a hemispherical shell, reconstruction cages, structural allografts, or custom triflange acetabular components. This paper will detail the necessary pre-operative evaluation, the intra-operative details, and the reported results of these acetabular revisions.

In vivo assessment of total hip femoral head separation from the acetabular cup during 4 common daily activities.

In vivo video fluoroscopies of well-functioning total hip arthroplasties (THA) have shown that femoral head separation from the medial articular bearing surface occurs during gait. Other activities may cause the same phenomenon. We examined this while patients performed the following 4 activities of daily living: pivoting to each side in stance, shoe tying, sitting down, and standing up. Ten healthy patients (5 men, 5 women, average age 66 years) all 1 year or more after cementless THA performed for degenerative arthritis, with Harris Hip Scores ≥90, were studied. Each patient performed the activities of daily living while data was captured using video fluoroscopy. Based on previously reported criteria, femoral head separation (the femoral head sliding lateral to the acetabular liner) was determined to be reliably predicted if the distance between the femoral head and acetabular cup was ≥0.5. Results showed that the greatest femoral head separation occurred during the pivoting activity (mean, 1.53 mm; range, 0.00-3.34 mm; SD, 1.05 mm). The separation values identified during pivoting occurred at the extremes of internal or external rotation for all patients. The other 3 activities showed lower separation distances. Separation during the pivoting activity exceeded the reported separations occurring during walking. This finding was seen in a small group of patients, and the data should be interpreted with caution. We conclude from this study that the evaluation of gait alone may not be sufficient to accurately assess femoral head separation occurring during activities of daily living for healthy, active patients.

A painful metal-on-metal total hip arthroplasty: a diagnostic dilemma.

Infection, loosening, osteolysis, or other causes can lead to the development of pain about a previously well-functioning total hip arthroplasty. An inflammatory reaction unique to metal on metal arthroplasty can lead to a painful total hip. A synovial biopsy is needed to make this specific diagnosis, and included in the differential diagnosis is infection. The workup of infection includes obtaining a C-reactive protein and erythrocyte sedimentation rate. Elevations of both the C-reactive protein and erythrocyte sedimentation rate are felt to indicate possible infection. This case report describes both of these findings and the treatment rendered in a painful subluxing metal-on-metal total hip arthroplasty presenting with ongoing pain and a large effusion.

Risks and Benefits of Simultaneous Bilateral Total Knee Arthroplasty

As the annual number of total knee arthroplasties has continued to increase, a concomitant increase in the number of bilateral total knee arthroplasties has occurred. Approximately 6% of primary total knee arthroplasties performed each year in the United States are performed on both knees as a single procedure with the patient under anesthesia (simultaneous bilateral total knee arthroplasty). This rate represents an almost twofold increase compared with the rate in the 1990s, when approximately 3.7% of all total knee arthroplasty operations were performed as a simultaneous bilateral total knee arthroplasty1. Because the fastest increase in total knee arthroplasty is occurring among younger people, a continued increase in the performance of simultaneous bilateral total knee arthroplasty is possible2. The identification of patients of all ages with symptomatic bilateral knee arthritis who are appropriate candidates for simultaneous bilateral total knee arthroplasty can be difficult. A major deficiency of the current orthopaedic literature is the absence of any adequately powered, prospective, controlled clinical trials that have directly compared simultaneous bilateral total knee arthroplasty with two total …

CORR Insights ® : Is TKA Using Patient-specific Instruments Comparable to Conventional TKA? A Randomized Controlled Study of One System

This CORR Insights® is a commentary on the article “Is TKA Using Patient-specific Instruments Comparable to Conventional TKA? A Randomized Controlled Study of One System” by Roh and colleagues available at: DOI: 10.1007/s11999-013-3206-1. The author certifies that he, or a member of his immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research ® editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR ® or the Association of Bone and Joint Surgeons®. This CORR Insights® comment refers to the article available at DOI: 10.1007/s11999-013-3206-1.

The Use of Augment Devices in Revision Acetabular Surgery.

As the number of total hip arthroplasties performed in the United States increases, and as more young patients undergo this procedure, it can be expected that the number of revision hip arthroplasties will also increase. Most acetabular revisions can be performed with a hemispherical shell. Results with these components show a rate of survivorship free of aseptic loosening of 97% (range, 94% to 100%) in 729 revision surgeries1-9 at a mean follow-up time of 9.8 years (range, six to 21.3 years). Use of a hemispherical shell requires the creation of a supportive, concave hemisphere of bone. While in the majority of acetabular revisions this goal is attainable, at times the nature of the acetabular osseous defect makes this goal unobtainable. This can be understood as the inability to ream a large enough hemisphere, with the goal of reaching the apex of the superior aspect of the deformity, without in the process removing supportive anterior and posterior host bone. In this setting, an oblong osseous deficiency is left over (defined as the superior to inferior length of the overall defect being greater than the anterior to posterior width of the remaining …

Hip fractures in the United States: Nationwide emergency department sample, 2008

To evaluate the recent epidemiology of hip fractures in the US.