Objective: To evaluate the evidence supporting the Semmes-Weinstein monofilament (SWM) and other threshold testing in preventing ulcers and amputation.
Search strategy: We searched the MEDLINE database using the Medical Subject Headings ("diabetic foot" or "diabetes mellitus" and ["foot ulcer" or "foot diseases"]) and ("sensory threshold" or "touch" or "vibration" or "monofilament [text word]" or "two point discrimination [text word]") restricted to studies with human subjects and published in the English language between 1985 and 2000.
Data abstraction: The studies were abstracted by one author (J.M.) and confirmed by the second author (J.S.).
Selection criteria: The studies had to contain original data collection and SWM or another threshold assessment method.
Data collection/analysis: All articles were abstracted for study design, testing method, population, and results.
Main results: We identified 6 prospective studies using SWMs and 4 with vibration perception thresholds (VPTs), including 1 randomized controlled trial. The increased risk of ulceration ranged from an odds ratio (OR) of 2.2 to 9.99, and the risk of amputation was a relative risk of 2.9 using the SWM and an OR of 4.38 to 7.99 for VPT. The randomized controlled trial of screening plus treatment for those with previous ulcers had no significant decrease in the number of ulcers or minor amputations but showed significantly fewer major amputations.
Conclusions: The SWM is currently the best choice for screening for clinically significant neuropathy because it is portable, inexpensive, painless, easy to administer, acceptable to patients, and provides good predictive ability for the risk of ulceration and amputation. Once the patient without protective sensation has been identified, management with protective footwear and patient education to prevent damage should be instituted but compliance is often difficult to implement.