Clothing accessory digs into joints (8,4)

I believe the answer is:

shoulder pads

I'm a little stuck... Click here to teach me more about this clue!

'clothing accessory digs into joints' is the definition.
I can't judge whether this definition defines the answer.

'accessory digs into joints' is the wordplay.
'accessory digs' becomes 'pad' (synonyms. I am not sure about the 'accessory' bit.).
'into' means one lot of letters goes inside another.
'joints' becomes 'shoulders' (shoulder is a kind of joint).
'pad' inserted inside 'shoulders' is 'SHOULDER PADS'.

Can you help me to learn more?

I've seen this clue in The Telegraph.

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