Identification of protective and 'at risk' HLA genotypes for the development of pseudotumours around metal-on-metal hip resurfacings.

Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around MoM hip resurfacings. A matched case-control study was performed using the prospectively-collected database at the host institution. In all, 16 MoM hip resurfacing 'cases' were identified as having symptomatic periprosthetic pseudotumours on preoperative metal artefact reduction sequence (MARS) MRI, and were subsequently histologically confirmed as high-grade aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) at revision surgery. 'Controls' were matched by implant type in the absence of evidence of pseudotumour. Blood samples from all cases and controls were collected prospectively for high resolution genetic a nalysis targeting 11 separate HLA loci. Statistical significance was set at 0.10 a priori to determine the association between HLA genotype and pseudotumour formation, given the small sample size. Using a previously-reported ALVAL classification, the majority of pseudotumour-positive caseswere found to have intermediate-grade group 2 (n = 10; 63%) or group 3 (n = 4; 25%) histological findings. Two further patients (13%) had high-grade group 4 lesions. HLA-DQB1*05:03:01 (p = 0.0676) and HLA-DRB1*14:54:01 (p = 0.0676) alleles were significantly associated with a higher risk of pseudotumour formation, while HLA-DQA1*03:01:01 (p = 0.0240), HLA-DRB1*04:04:01 (p = 0.0453), HLA-C*01:02:01 (p = 0.0453), and HLA-B*27:05:02 (p = 0.0855) were noted to confer risk reduction. These findings confirm the association between specific HLA genotypes and the risk of pseudotumour development around MoM hip resurfacings. Specifically, the two 'at risk' alleles (DQB1*05:03:01 and DRB1*14:54:01) may hold clinical value in preoperative screening and prospective surgical decision-making.

Third and fourth generation ceramic-on-ceramic total hip arthroplasty at a minimum of ten years.

Background: Ceramic on Ceramic bearings in Total Hip Arthroplasty (THA) afford a low friction coefficient, low wear rates and extreme hardness. Significant complications include hip squeak, ceramic fracture and poor polyethylene performance in revision procedures due to imbedding of abrasive microscopic ceramic fragments. We report on the results of this bearing at a minimum of 10 years. Methods: A single-centre retrospective review of 449 THAs was performed. Primary outcome measures included aseptic revision and all-cause revision rates at a minimum of 10 years post operatively. Evaluation of functionality was performed with WOMAC and SF-36 scores which were performed pre-operatively and at intervals of 6 months, one year, 2 years, 5 years and 10 years post operatively. Results: There was a 6.2% (n = 28) all-cause and 5.3% (n = 24) aseptic revision rate for ceramic on ceramic total hip arthroplasty at minimum of 10 years with a mean time to revision 4.8 years (range 2 months-11.6 years). Notably, there were 2 revisions for ceramic head fracture, one for ceramic liner fracture, 3 for aseptic loosening and 3 revisions for squeaking. Pain of unknown origin was the most common reason for revision. There was an improvement in postoperative WOMAC scores from a mean of 59.8 (range 15-95) pre-operatively to a mean of 15.6 (range 0-78) at 10 years. Conclusion: This study showed good functional outcomes but high revision rates for CoC THA at a minimum of 10 years. Our rates of ceramic fracture were consistent with other studies.

Methods to Mitigate Industry Influence in Industry Sponsored Research.

Medical and surgical research has always had a long-standing relationship with industry-based funding from sources, such as drug and device companies. Concerns exist surrounding the association between funding sources, outcome from studies and publication bias. Studies demonstrating increased odds ratios associated with positive results in industry sponsored studies across medicine have stimulated Cochrane reviews, literature reviews and other articles to examine this relationship further. In spine surgery in particular, studies with positive results have an odds ratio of 3.3 of being published. This article discusses the biases associated with industry sponsorship, possible ways to reduce such biases and ways to improve transparency in research relationships. This article explores the types of bias that can be encountered at different stages of research including previous trials in spine surgery. The means of improving transparency including the Physician Payment Sunshine Act of 2010 and International Committee of Medical Journal Editors (ICJME) accreditation are discussed. We recognize that physicians undertaking industry sponsored research should be protected and not be liable to perverse incentives. We conclude that mitigating bias in industry sponsored research is a multistep process and needs a multifaceted approach. The main beneficiary of research should be patients and as such a collective effort from medical professionals, health care institutions, journals and industry should approach research, and publications with that in mind.

What Is Finite Element Analysis?

Finite element analysis is a computational technique to predict how different materials will react when a range of forces are applied. In the field of orthopedics, this technique has predominantly been used for implant design and testing. As the technology improves, increasing clinical applications are being developed, offering promise in the areas of surgical planning and the opportunity to tailor implants to individual patient characteristics. This article introduces the various preclinical mechanical tests available, as well as providing a brief overview of the finite element analysis technology.

Advantages and Design of PROMIS Questionnaires.

The Patient-Reported Outcomes Measurement Information System (PROMIS) is a National Institute of Health initiative to improve the measurement of clinically important symptoms and outcomes. Patient-Reported Outcomes capture health outcomes that are relevant to the daily functioning of the patient and include the monitoring of physical, mental, and social health. PROMIS offers a standardized tool to measure Patient-Reported Outcomes for use in both the clinical and research setting. It is a flexible and dynamic tool for both patient and clinician, and its use is continuing to grow internationally. This article discusses the rationale and design of this tool, as well as its advantages to both research and clinical practice.