Hvis hoften stadig gør ondt overmorgen, bestiller vi tid til en ny undersøgelse.

Hvis means if. It introduces a conditional subordinate clause:

Hvis hoften stadig gør ondt overmorgen
= If the hip still hurts the day after tomorrow

So the sentence sets up a condition first, and then gives the result in the main clause.

This is because Danish follows the V2 rule in main clauses: the finite verb normally comes in the second position.

Here, the whole Hvis... clause comes first:

Hvis hoften stadig gør ondt overmorgen, ...

That entire clause counts as the first element, so the verb in the main clause must come next:

bestiller vi tid...

If you started with the main clause by itself, you would say:

Vi bestiller tid til en ny undersøgelse.

But after a fronted clause, Danish changes the order:

Hvis ..., bestiller vi ...

Hofte means hip, and hoften means the hip.

• en hofte = a hip
• hoften = the hip

Danish adds -n to many common-gender nouns to make them definite. Since the sentence refers to a specific hip already understood from context, it uses hoften.

Gør ondt is a very common Danish expression meaning hurts or is painful.

Literally, it looks like does hurt/pain, but you should learn it as a set phrase:

• Det gør ondt. = It hurts.
• Hoften gør ondt. = The hip hurts.

So in this sentence:

hoften stadig gør ondt
= the hip still hurts

Ondt is the form used in the fixed expression gøre ondt.

The adjective is related to ond, but in this expression Danish uses ondt. So you should think of gøre ondt as a whole unit rather than trying to build it word by word.

A learner-friendly way to remember it is:

• gøre ondt = to hurt

not

• gøre ond

Stadig means still.

In this subordinate clause, it comes before the finite verb:

Hvis hoften stadig gør ondt...

This is normal Danish word order in subordinate clauses. English speakers often expect something more like English word order, but Danish often places adverbs like stadig before the verb in subordinate clauses.

So:

• hoften stadig gør ondt = the hip still hurts

Overmorgen means the day after tomorrow.

Danish often uses single words where English uses longer phrases:

• i morgen = tomorrow
• overmorgen = the day after tomorrow

So yes, it is normal that it is written as one word.

Danish very often uses the present tense for future meaning when the time is clear from context.

Here, overmorgen already makes the future obvious:

Hvis hoften stadig gør ondt overmorgen...

So Danish does not need a special future form here. English does something similar sometimes too, but Danish uses this pattern very naturally.

Bestille tid is an idiomatic Danish expression meaning to book/make an appointment.

So:

• bestille tid = book an appointment
• bestille en tid can sometimes be heard, but bestille tid is very common and natural

The noun tid here is used in a more general, idiomatic way, so the article is often omitted.

Here til means for:

bestiller tid til en ny undersøgelse
= book an appointment for a new examination

So the structure is:

• bestille tid til noget = to book an appointment for something

Examples:

• bestille tid til lægen = book an appointment with/for the doctor
• bestille tid til en undersøgelse = book an appointment for an examination

Undersøgelse is a common-gender noun:

• en undersøgelse = an examination
• undersøgelsen = the examination

So the indefinite article is en.

The adjective ny means new, and here it stays in its basic form because it matches a singular common-gender noun:

• en ny undersøgelse = a new examination

Yes, that is also possible, but it is a slightly different structure.

This sentence says:

Hvis hoften stadig gør ondt overmorgen...
Literally: If the hip still hurts...

Another natural Danish way is:

Hvis vi stadig har ondt i hoften overmorgen...
= If we still have pain in the hip the day after tomorrow...

So Danish can describe pain either by making the body part the subject:

• Hoften gør ondt.

or by making the person the subject:

• Vi har ondt i hoften.

Both are natural, but the original sentence focuses directly on the hip.

Yes, a few words may be tricky for English speakers:

• hvis: the h is usually silent, so it sounds roughly like vis
• hoften: the t is usually soft or not strongly pronounced
• gør: the vowel is difficult for English speakers; it is a rounded Danish vowel
• ondt: the final dt cluster is not pronounced the way it is spelled
• overmorgen: spoken Danish often smooths this out a lot in fast speech

The biggest thing is that spoken Danish is often much less clear from the spelling than English learners expect, so it helps to hear the whole sentence aloud several times rather than trusting the spelling alone.