Sounds horribly painful and my thoughts are with your husband.
If you are new to homeopathy, I would suggest that 30C potencies are what I consider to be the most useful.
However, having said that, the energy of the ailment has to be taken into consideration and the age/vital force of the patient.
Prescribing in a classical manner, before an operation, I would suggest an Arnica 30C. Only take another Arnica if there is much pain or bruising after the operation. (again... Less is more in homeopathy...)
If there is an adverse reaction to anaesthesia, I would give a Phos 30C. In Aust, the nurses in the ward give ice to patients recently returned from theatre, rather than water, and I have found that when this hits stomach temperature, in susceptible people, the nausea often begins.

caution again...

If there is nerve pain after surgery, then a 30C Hypericum. 1 dose only.
If the ankle is not enclosed in plaster or fibreglass, then bathing the affected limb in Hypericum tincture will act as an "antiseptic" and nerve healer, but don't do both. Work with what remedies you do have access to.
No vomiting/nausea or nervine pain - then just take an Arnica.
Later you could go to another remedy if indicated.

I have found that basically if doubt about something - don't do it!

Light massage, starting at the top of the leg toward the heart and then working toward the affected area(difficult if in plaster) will keep the lymph flowing and reduce the likelihood of DVT. (An aspirin - extract of willow bark - will also have a blood thinning effect. A full strength aspirin can affect the platelet clotting effects for about 5-6 days)