Journal Club

1. Journal Club Young et al (2000) The durability of the Semmes-Weinstein 5.07 monofilament

2. Article Summary • This quantitative research tested 10 x 10g monofilaments up to 1500 times in order to determine if the pressure exerted by the filament reduces significantly with repetitive use • It was found that there was a significant different between 0 cycles, 500 cycles, 1000 cyclesand 1500 cycles • After every 500 cyclesthe filaments were rested for a minimum of 2 hours in which it was found the filaments recovered some of their force- possibly due to the nylon ‘memory’ • Some further investigation was done for up to 5000 cycleson two filaments which showed further reduction in pressure exerted by the filaments

3. Why it was conducted • Podiatrists had reported that the filament formed a natural bow after prolonged use which led to concerns about how effective the instruments were • This could have clinical repercussions, such as false positive diagnosis of neuropathy, as the pressure applied would not be the correct 10g • It seeks to discover the number of times a Semmes-Weinstein 10g monofilament can be used before it loses 10g of force – This is important because Birkes and Sims (1985) concluded in their research that sensitivity to the 10g monofilament was the best indicator of the minimum level of protective sensation in the foot • The problem of neuropathy is a serious one in diabetic patients and if a false positive diagnosis occurs, a great deal of concern can be caused and resources spent unnecessarily

4. Is a clear question asked? ‘The study was designed to determine the number of applications a filament could receive before it no longer delivered the 10g filament force’ However…. There is no clear stated hypothesis Such as: ‘that filament force will decrease in line with increased usage’

5. Is the method clear? • They used an Intron Dynamic Testing Instrument to secure the monofilament and apply the pressure to simulate a neurological examination as used in practice • the filament was secured in this machine perpendicular to a Mettler PM 2000 which measured the filament force applied in grams • The initial force of each filament was measured and then set to perform 100 cycles (i.e push the monofilament onto the Mettler Pm 2000 100 times) - 1 cycle is 1 touch of the filament against the force plate • The filament forces were then measured every 100 cycles up to 1500 cycles on all 10 of the monofilaments

6. What does that research achieve? • Originality of the study: It is the first to test this. Previous research by Levin (1977) found under what circumstances monofilaments should be considered unreliable, such as in high temperatures Raises awareness of limitations of the 10g monofilament: • Importance of rest times: at regular intervals if instruments are used repetitively to maintain reliability of results. For example after every 100 uses • Age of instrument: affects it’s reliability in testing the patients affectively

7. Positives of the research • Very clear set up • Good presentation of data, with tables and graphs, that are explained • Appropriate design was used to test the study • Two suitable statistical tests were used, the F test and Duncans multiple range test. Both found significant results. • Good referencing, with most key statements made supported by evidence • Pilot data was collected beforehand though with only 5 monofilaments (i.e to test filament alignment and positioning) • Good control of variables

8. Limitations of the research • Small sample size: with only 10 monofilaments tested and all from the same manufactured batch. Also only two filaments were tested up to 5000 cycles which is too small to obtain reliable results • Unspecified resting time: The monofilaments are rested for a period of at least 2 hours after 500 cycles – this is not specific or constant meaning some filaments may have regained a better original shape than others • Unclear statements:such as mention of nylon “memory” but no references or discussion as to what this is • Needs further discussion and research: on what is an acceptable loss of pressure of the monofilament • And to suggest a more reliable way of using the monofilament or help in the development of a better tool for testing protective neurological sensation. • Slight different length monofilaments: due to manufacturing, which affected the force that the monofilaments applied. Slightly shorter filaments= less force.

9. ......But overall it appears to be a well conducted and presented piece of research that is useful to practitioners! Any Questions?