Regarding the interesting S(AD) SAD system of ulcer classification (Macfarlane and Jefferson, The Diabetic Foot 2(4): 123-131). In any grading system one should avoid situations where the difference between grades may be so minimal as to be insignificant. One should also avoid too complex a system: one which is suitable for research may well not be ideal for everyday clinical practice. We agree that any grading system which does not differentiate between the neuropathic and the neuroischaemic foot would be useless both for clinical and research purposes.
Neuropathy and/or ischaemia and/or infection is involved in almost every ulcerative lesion of the diabetic foot and should be included in any grading system. A major problem with the widely used Wagner system is that these factors are not all included.
When grading ischaemia, the authors distinguish between a foot where both pulses are easily felt, a foot where there is diminution of both pulses or absence of one, absence of both pulses, and gangrene. However, this is not a practical grading system. In practice, if both pulses can be clearly felt, or even if there is just one palpable pulse per foot, then ischaemia is rarely a problem. In this part of the S(AD) SAD grading system, gangrene is assumed to be due to worsening ischaemia. However, it may be due to secondary infection of an ischaemic ulcer, or even a neuropathic ulcer.
Furthermore, in grading infection, there is no mention of wet gangrene, which is the progression of infection when cellulitis is not controlled. Gangrene may therefore be due either to ischaemia or to infection but is only mentioned in the ischaemia section of S(AD) SAD.
The authors introduce a grading system for neuropathy, which includes the Charcot foot, which is a totally separate entity to ulceration and confuses the issue. (Why, if they include Charcot foot, do they not include painful neuropathy?) Why do they not use the 10g monofilament? This is the most widely used and practical technique for quantitating neuropathy.
