Etter at hun tok smertestillende, kunne hun gå forsiktig ned trappen uten at ankelen gjorde så vondt.

Etter at means after when it is followed by a full clause.

So:

Etter at hun tok smertestillende
= After she took painkillers / pain medication

Why two words?

• etter = after
• at = a subordinating conjunction introducing a clause

If you only had a noun phrase, you would not need at:

• etter middagen = after dinner

But with a subject and verb, Norwegian normally uses etter at:

• etter at hun tok ... = after she took ...

Because the whole sentence describes a situation in the past.

• tok = took
• kunne = could / was able to
• gjorde = did in the idiom gjøre vondt

The timeline is:

1. She took pain medication.
2. After that, she was able to walk down the stairs.
3. Her ankle did not hurt as much during that time.

So the sentence is telling a past sequence of events, which is why all the finite verbs are in the preterite.

This is because of Norwegian V2 word order in main clauses.

The sentence starts with a fronted element:

Etter at hun tok smertestillende, ...

When something other than the subject comes first in a Norwegian main clause, the finite verb must come next. That gives:

• Etter at hun tok smertestillende, kunne hun gå ...

Not:

• Etter at hun tok smertestillende, hun kunne gå ... ❌

So kunne comes before hun because the sentence opens with the time clause.

Smertestillende means pain-relieving or, as a noun, pain medication / painkillers.

In this sentence, it is being used like a noun:

• tok smertestillende = took pain medication / took painkillers

There is no article because Norwegian often uses this word in a general, collective way, similar to English pain medication.

So this does not necessarily mean one single pill. It refers more generally to pain-relief medicine.

In this sentence, kunne is best understood as was able to.

• kunne hun gå forsiktig ned trappen
  = she could / was able to walk carefully down the stairs

English could can sometimes mean either ability or possibility, and Norwegian kunne works similarly. Here the context makes it clear that the medicine made it possible for her to walk, so was able to is a very natural interpretation.

Forsiktig means careful, but it can also function as an adverb meaning carefully.

So:

• gå forsiktig = walk carefully

Norwegian does not have a separate -ly ending like English. Very often, the adjective form is also used adverbially.

That is why forsiktig can mean both:

• en forsiktig person = a careful person
• hun gikk forsiktig = she walked carefully

Literally, it means walk down the stairs / staircase.

• gå = walk / go
• ned = down
• trappen = the stairs / the staircase

Norwegian often uses gå ned trappen where English says go down the stairs. So even if English uses go, Norwegian may use gå very naturally.

Because both refer to specific, known things.

• trappen = the stairs / the staircase
• ankelen = the ankle

In context, it is a particular staircase and a particular ankle, so the definite form is natural.

With body parts, Norwegian very often uses the definite noun where English might prefer a possessive:

• ankelen gjorde vondt = her ankle hurt

Norwegian does not need to say hennes ankel here, because it is already obvious whose ankle is meant.

Uten at means without followed by a full clause.

Here:

uten at ankelen gjorde så vondt
= without the ankle hurting so much

This is different from uten å, which is used with an infinitive:

• Hun gikk uten å klage = She walked without complaining

But in your sentence, the part after uten has its own subject, ankelen, so Norwegian needs uten at + clause:

• uten at ankelen gjorde ...

Gjøre vondt is a very common Norwegian expression meaning to hurt.

So:

• Ankelen gjør vondt = The ankle hurts
• Ankelen gjorde vondt = The ankle hurt

It uses vondt, not vond, because this expression is a fixed idiomatic pattern.

A useful comparison:

• Ankelen er vond = The ankle is sore/painful
• Ankelen gjør vondt = The ankle hurts

Both are possible, but they are different structures.

Here så means something like so much, so badly, or that much.

So:

• gjorde vondt = hurt
• gjorde så vondt = hurt so much / hurt that badly

In the full sentence, it suggests that the pain was reduced after she took the medication:

• uten at ankelen gjorde så vondt
  = without the ankle hurting so much

So så adds the idea of degree, not just the fact of pain.