Many are afraid of statistics. However, it is important to realise that we need to learn statistics mainly to act as a data consumer, not data analyser. As such a basic understanding is all that is required. A few years back Prof. Aviva Petrie published an excellent write-up in JBJS which is sufficient for exam purposes.

For those more inclined there is "Statistics at square one": a best seller and now available free on the internet.

I would suggest additional reading on Kaplan-Meier analysis. This is much favoured by the examiners. Make sure you understand survival analysis, best place to practice is to look up the NJR results, it is full of survival graphs.