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Traumeel for knee swelling, a biased trial

PainSci » bibliography » Thiel et al 1994
Tags: homeopathy, controversy, inflammation, debunkery, pain problems

One article on PainSci cites Thiel 1994: Does Arnica Gel Work for Pain?

PainSci commentary on Thiel 1994: ?This page is one of thousands in the bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided wherever possible.

A very old German experiment, in a journal owned by Traumeel’s manufacturer, straightforwardly claims to have found clear evidence that Traumeel is better than a placebo by several measures (very similar to Böhmer). It has a reasonably strong design. Thiel and Borho compared pain, swelling and range of motion in 73 freshly injured knees (hemarthrosis, bloody swelling). Although the results as summarized by the authors sound pretty good, they are playing with statistics. They set a threshold for “therapeutic” success that conveniently makes it seem like Traumeel worked way better than placebo, when in fact the results were sitting just on either side of the threshold — a modest actual difference. The results they report are positive for Traumeel, but using a threshold like that is a terrific way of exaggerating the results.

This actual differences were of the size than can all too easily be explained by fluke, error and biased reporting. For instance, it’s interesting that the authors point out that, just by chance, twice as many people getting the placebo were overweight — a likely risk factor for slower healing from a knee injury, and just the sort of thing that can create the illusion of a difference. It’s a terrific example of how relatively minor effects can vanish in a puff of statistics.

As with most Traumeel research available, the risk of bias is unusually high here. Thiel and Borho are undoubtedly extremely biased experimenters. They assume that the efficacy of Traumeel is “proved” on the basis of “a number of medical experience reports.” This is not an acceptable standard of evidence — indeed, it is almost the lowest possible.

This is one of ten studies cited on to substantiate that Traumeel has therapeutic effects. See Does Arnica Gel Work for Pain? for a full discussion of these references as a set.

~ Paul Ingraham

original abstract Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

In a randomized, placebo-controlled double-blind trial, 73 patients with traumatic hemarthrosis of the knee joint were immediately treated by puncture of the knee and by intra-articular administration of either 2 m Traumeel N or physiological saline solution 3 times over a period of 8 days. None of the injuries warranted surgical intervention.

After a single injection, 13.5% of the patients in the verum group required further punctures, which was markedly lower than the 25% in the placebo group. On the 8th day after the start of treatment, the punctate was still bloody for 5.4% in the verum group and 19.4% in the placebo group. An improvement in the degree of joint movement between the healthy knee and the injured, treated knee of 0 to 10 degrees was taken as the criterion for therapeutic success, along with a simultaneous improvement in the difference in the circumference of the joints of a maximum 0.5 cm. In the verum group, 78.4% of cases were improved with respect to extent of movement as against 38.9% in the control group. The treatment also proved to be successful With reference to a reduction in the circumference of the joint and the total pain scores. All of the patients included in the study tolerated the treatment without any drug-related adverse effects.

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