I do not have access to the Lancet journal article, but in the abstract it says this:
"In men with smaller femoral heads, resurfacing resulted in poor implant survival. Predicted 5-year revision rates in 55-year-old men were 4·1% (3·3—4·9) with a 46 mm resurfacing head, 2·6% (2·2—3·1) with a 54 mm resurfacing head, and 1·9% (1·5—2·4) with a 28 mm cemented metal-on-polyethylene stemmed THR. Of male resurfacing patients, only 23% (5085 of 22076) had head sizes of 54 mm or above."
My first thought when I saw that they were comparing a 28 mm cemented metal-on-polythene with HR is that it did "better" after five years because of the extreme activity restrictions associated with this kind of implant!
In the abstract they blow off reporting on "only" 23% of the data (that's one in four!), which seems to me to indicate some kind of bias. I can only imagine that they don't mention results on this group because HR did better. Also, I wonder why they focus specifically on five year data (and not a longer period) since apparently longer term data was available. A lot depends on how you organize the data. For example, what if you divide the data into two groups: those above, say, 52 mm and those below? I wouldn't be at all surprised if their data showed that in the group above 52 mm HR did as well or better than the THR group. I bet the longer term data would be even more definitive (it seems to me that most failures in HR come from fracture or acetabular component problems both which show up in less than five years). Even more important, I hope the researchers were unbiased enough to factor out problems with the faulty ASR device. Since I don't have access to the article I can't say anything for sure.
Here´s my personal opinion about this: even given that five year revision rates of a 46mm head HR are more than double that of a 28mm metal on polythene THR, if I had this hip size I would be more than willing to take that risk for the much increased functionality of the HR. The problem with the 28 mm ball is that you can dislocate your hip bending over or kneeling down. And it is well established that such an implant does not last very long or work very well in younger patients.