Are the High Hip Fracture Rates Among Norwegian Women Explained by Impaired Bone Material Properties?

Hip fracture rates in Norway rank among the highest in the world, more than double that of Spanish women. Previous studies were unable to demonstrate significant differences between the two populations with respect to bone mass or calcium metabolism. In order to test whether the difference in fracture propensity between both populations could be explained by differences in bone material quality we assessed bone material strength using microindentation in 42 Norwegian and 46 Spanish women with normal BMD values, without clinical or morphometric vertebral fractures, no clinical or laboratory signs of secondary osteoporosis, and without use of drugs with known influence on bone metabolism. Bone material properties were assessed by microindentation of the thick cortex of the mid tibia following local anesthesia of the area using the Osteoprobe device (Active Life Scientific, Santa Barbara, CA, USA). Indentation distance was standardized against a calibration phantom of methylmethacrylate and results, as percentage of this reference value, expressed as bone material strength index units (BMSi). We found that the bone material properties reflected in the BMSi value of Norwegian women was significantly inferior when compared to Spanish women (77 ± 7.1 versus 80.7 ± 7.8, p < 0.001). Total hip BMD was significantly higher in Norwegian women (1.218 g/cm² versus 0.938 g/cm², p < 0.001) but regression analysis revealed that indentation values did not vary with BMD r² = 0.03 or age r² = 0.04. In conclusion Norwegian women show impaired bone material properties, higher bone mass, and were taller than Spanish women. The increased height will increase the impact on bone after falls, and impaired bone material properties may further enhance the risk fracture after such falls. These ethnic differences in bone material properties may partly explain the higher propensity for fracture in Norwegian women. © 2015 American Society for Bone and Mineral Research.     

AN ELASTIC EXERCISE BAND MOUNTED WITH A BANDCIZER? CAN DIFFERENTIATE BETWEEN COMMONLY PRESCRIBED HOME EXERCISES FOR THE SHOULDER

Background

Home‐exercise is commonly prescribed for rehabilitation of the shoulder following injury. There is a lack of technology available to monitor if the patient performs the exercises as prescribed.

Purpose

The purpose of this study was to investigate the validity of using three dimensional (3D) gyroscope data recorded with the Bandcizer™ sensor to differentiate between three elastic band exercises performed in the shoulder joint: abduction, flexion, and external rotation.

Design

Concurrent validity study.

Methods

This study was performed over two phases. In the first phase, 20 subjects performed three sets of 10 of shoulder abduction, external rotation and flexion exercises with a Thera‐Band mounted with a Bandcizer, while supervised by a physical therapist. The Bandcizer has an inbuilt three‐dimensional gyroscope, capable of measuring angular rotation. Gyroscope data were analyzed in Matlab, and a one‐way ANOVA was used to test for significant differences between each of the three exercises. An algorithm was then created in Matlab based on the exercise‐data from the gyroscope, to enable differentiation between the three shoulder exercises. Twenty new subjects were then recruited to cross‐validate the algorithm and investigate if the algorithm could differentiate between the three different shoulder exercises.

Results

A blinded assessor using the Matlab algorithm could correctly identify 56 out of 60 exercise sets. The kappa agreement for the three exercises ranged between 0.86‐0.91.

Conclusion

The ability to differentiate between the home exercises performed by patients after shoulder injury has great implications for future clinical practice and research. When home exercises are the treatments‐of‐choice, clinicians will be able to quantify if the patient performed the exercise as intended. Further research should be aimed at investigating the feasibility of using the Bandcizer™ in a home‐based environment.

Word count

2429

Level of Evidence

2     

Schizophrenia and Metacognition: An Investigation of Course of Illness and Metacognitive Beliefs Within a First Episode Psychosis

Cognitive Therapy and Research - The Self Regulatory Executive Function (S-REF) model implicates maladaptive metacognitive beliefs and processes in the predisposition and/or maintenance of positive...     

Characterization of metalloprotease cleavage products of human articular cartilage

OBJECTIVE: To identify, characterize, and compare proteolysis peptide products generated by metalloprotease digests of human articular cartilage. METHODS: Human articular cartilage was digested by the addition of exogenous metalloproteases, including matrix metalloproteinases 2, 3, 8, 9, 12, and 13 and aggrecanases ADAMTS-4 and ADAMTS-5. Proteolyzed peptide products were identified by proteomics methods using mass spectrometry. RESULTS: Complete sequences of the peptides proteolyzed from human articular cartilage, including N- and C-termini and hydroxylated posttranslational modifications, were determined. A wide variety of peptides, originating from types I, II, and III collagen, biglycan, prolargin, fibromodulin, fibronectin, decorin, cartilage oligomeric matrix protein, cartilage intermediate-layer protein, megakaryocyte-stimulating factor, mimecan, aggrecan, and lumican, was analyzed following metalloprotease digestion. Release of peptides varied as a function of time, enzyme specificity, and abundance. Specific type II collagen peptide biomarkers, including those containing the three-quarter-length fragment cleavage site and those containing the domains for helical peptide of type II collagen and C-telopeptide of type II collagen, were observed after release by selected proteases. CONCLUSION: The use of intact cartilage instead of purified protein substrates in the assay allowed for the identification of novel potential substrates and cleavage sites for individual enzymes under more physiologically relevant conditions. Characterization of these cartilage matrix peptides may help in the development of pharmacodynamic biomarkers of cartilage degradation, and also may contribute to an understanding of the bioactive peptides important in chondrocyte signaling.