Both sides: together or staged?

Options

Simultaneous, or staged months apart

Simultaneous stay

Typically longer than a single side

Staged interval

Usually 3 to 6 months

Knees

Simultaneous considered in selected fit patients

Hips

Usually staged

Deciding factor

Medical fitness, not convenience

What it is.

A proportion of patients have arthritis badly enough on both sides that one operation will not solve the problem. That raises a question that is asked often and answered too casually: should both be done at once?

Two approaches:

• Simultaneous, sometimes called single-stage. Both joints replaced under one anaesthetic, in one admission.
• Staged. Two separate operations, typically three to six months apart.

The attraction of doing both at once is obvious: one anaesthetic, one admission, one recovery, one period off work. The case against is that the physiological load of two joint replacements in one sitting is not simply twice as manageable as one.

How it is performed.

What the evidence shows

For knees, simultaneous bilateral replacement has been studied extensively. Compared with staged surgery it is associated with a shorter total hospital stay, a shorter total recovery, and lower overall cost. It is also associated with higher rates of transfusion, and in some series higher rates of cardiac and pulmonary complications, particularly in older patients and those with cardiac disease.

The important qualifier is selection. Studies reporting good outcomes are generally reporting on carefully selected, medically fit patients. The results do not transfer to patients who would not have been selected.

For hips, simultaneous bilateral replacement is performed less commonly. Part of that is practical: recovery after a hip replacement depends on weight bearing comfortably on the other leg, and having two operated hips makes early mobilisation harder. Most bilateral hip replacement is staged.

How the decision is made

Against three things:

1. Medical fitness. Cardiac and respiratory reserve, kidney function, haemoglobin. This is an anaesthetic assessment and it is the deciding factor.
2. The state of both joints. If one side is clearly worse, doing that side alone often improves the other substantially by restoring gait and alignment. Patients are regularly surprised how much better the second side feels once the first is fixed, and a proportion never proceed with it.
3. Support at home. Recovering from two knee replacements at once is considerably harder than one, and it requires help. Someone living alone is usually better served by staging.

The usual recommendation

In this practice, staging is the default and simultaneous surgery is considered on request in patients who are medically fit, well supported at home, and have genuinely symmetrical disease. Doing the worse side first and reassessing is often the most useful plan, because it answers the question about the second side with information rather than prediction.

Recovery timeline.

Staged. Each side follows the standard recovery for that operation. The second is usually easier, because you know the process and the first joint is now helping rather than hindering.

Simultaneous. The early phase is harder. There is no good leg to take weight through, walking aids are needed longer, and inpatient rehabilitation is more often required. Beyond about three months the trajectory converges with staged surgery.

• Hospital. Longer than a single joint, often with a period of inpatient rehabilitation.
• Aids. Expect to need them longer.
• Help at home. Not optional. Arrange it before the operation.

Outcomes.

Both approaches produce good long-term results, and by a year the functional outcomes are similar. The differences sit in the early period and in the risk profile.

Simultaneous surgery in appropriately selected patients: less total time in hospital, faster overall return to function, one anaesthetic, lower total cost. Higher transfusion rates and, in less fit patients, higher rates of medical complication.

Staged surgery: lower physiological load each time, easier early rehabilitation, and the option of not proceeding with the second side. Two anaesthetics, two recoveries, longer overall.

Anyone recommending simultaneous surgery should be able to explain why you specifically are a suitable candidate, not simply that it is more convenient.

Rehabilitation.

The programme for each joint is unchanged. What changes after simultaneous surgery is that both legs are recovering at once, so progression is governed by the slower side and aids are needed for longer.

Protocols via For Physiotherapists.

Questions worth asking at your consultation.

Every one of these is a fair question and none of them should be awkward to ask. Print them or bring them on your phone.

• Am I a good candidate for bilateral joint replacement, and what would make me a poor one?
• What are the alternatives, including doing nothing for now?
• How many of these do you perform in a year?
• What does the Australian registry say about the implant you would use for someone my age?
• What does a realistic result look like for me specifically, and what will I still not be able to do?
• What is your plan if it does not go well?

Frequently asked questions.

References.

1. Australian Orthopaedic Association National Joint Replacement Registry. Annual Report. Adelaide: AOA.
2. Hu J, Liu Y, Lv Z, et al. Mortality and morbidity associated with simultaneous bilateral or staged bilateral total knee arthroplasty: a meta-analysis. Arch Orthop Trauma Surg. 2011;131(9):1291-1298.

This page provides general information about a medical condition and a surgical procedure. It is not individual medical advice and does not replace consultation with a qualified practitioner. Outcomes vary between individuals and all surgery carries risk. A referral is needed for a consultation with Professor Daevyd Rodda; without one, you can start with the practice nurse practitioner, who can provide it.