Have levels of evidence improved the quality of orthopaedic research?

BACKGROUND: Since 2003 many orthopaedic journals have adopted grading systems for levels of evidence (LOE). It is unclear if the quality of orthopaedic literature has changed since LOE was introduced. QUESTIONS/PURPOSES: We asked three questions: (1) Have the overall number and proportion of Level I and II studies increased in the orthopaedic literature since the introduction of LOE? (2) Is a similar pattern seen in individual orthopaedic subspecialty journals? (3) What is the interobserver reliability of grading LOE? METHODS: We assigned LOE to therapeutic studies published in 2000, 2005, and 2010 in eight major orthopaedic subspecialty journals. Number and proportion of Level I and II publications were determined. Data were evaluated using log-linear models. Twenty-six reviewers (13 residents and 13 attendings) graded LOE of 20 blinded therapeutic articles from the Journal of Bone and Joint Surgery for 2009. Interobserver agreement relative to the Journal of Bone and Joint Surgery was assessed using a weighted kappa. RESULTS: The total number of Level I and II publications in subspecialty journals increased from 150 in 2000 to 239 in 2010. The proportion of high-quality publications increased with time (p < 0.001). All subspecialty journals other than the Journal of Pediatric Orthopaedics and the Journal of Orthopaedic Trauma showed a similar behavior. Average weighted kappa was 0.791 for residents and 0.842 for faculty (p = 0.209). CONCLUSIONS: The number and proportion of Level I and II publications have increased. LOE can be graded reliably with high interobserver agreement. The number and proportion of high-level studies should continue to increase.

Amphotericin B delivery from bone cement increases with porosity but strength decreases.

BACKGROUND: Amphotericin B is a highly hydrophobic antifungal used for orthopaedic infections. There is disagreement about whether amphotericin B is released when it is loaded in polymethylmethacrylate (PMMA). It is unknown how much a poragen will increase amphotericin B release or decrease the compressive strength of the PMMA. QUESTIONS/PURPOSES: We therefore measured amphotericin B release and the compressive strength of amphotericin B loaded bone cement with and without adding high-dose poragen. METHODS: Antifungal-loaded bone cement was formulated with Simplex P cement and 200 mg amphotericin B with and without 10 g cefazolin (poragen) per batch. Twenty standardized test cylinders were eluted in deionized water for each formulation. Cumulative amphotericin B mass and compressive strength were measured. Data were analyzed using repeated-measures analysis of variance. RESULTS: Antifungal-loaded bone cement (ALBC) with 10 g poragen delivered more amphotericin B than ALBC containing amphotericin B alone by Day 15, 12.76 µg/cylinder (0.5%) versus 1.74 µg/cylinder (0.04%), respectively. With amphotericin B alone, compressive strength was unchanged and compressive strength did not decrease during elution. Adding 10 g poragen to ALBC with 200 mg amphotericin B decreased the compressive strength and compressive strength decreased further during elution, 80, 61, and 46 MPa at 0, 1, and 30 days, respectively. CONCLUSIONS: Amphotericin B is released in very small amounts from antifungal-loaded bone cement. Release can be increased by adding high-dose poragen, but compressive strength decreases sufficiently to limit its use for implant fixation.