Will I Need My Other Hip Replaced?

It's one of the most common questions I hear: “If you fix this hip, will I need the other one done too?” The honest answer is that it depends — and what it depends on most is why you needed the first hip replaced in the first place. Some diagnoses tend to affect both hips; others are confined to one side. Here's how I think it through with patients.

It depends on the diagnosis

Hip replacements are performed for many different reasons, and the diagnosis is the single best predictor of whether the other side will eventually need attention. Common reasons include:

• Osteoarthritis
• Avascular necrosis (osteonecrosis), including steroid- or medication-induced
• Rheumatoid and other inflammatory arthritis
• Hip dysplasia (including developmental dysplasia, DDH)
• Femoroacetabular impingement (FAI)
• Post-traumatic arthritis and prior hip fracture
• Legg-Calvé-Perthes disease
• Arthritis after prior hip surgery

Which conditions tend to affect both hips?

A useful way to think about it is whether the cause is systemic/developmental (affecting the whole body or both hips' development) or localized (confined to one injured hip):

Primary osteoarthritis sits in between — it can be one-sided or affect both hips over time. To understand the most common driver, see hip osteoarthritis, and for the systemic and developmental causes, avascular necrosis, hip dysplasia, and hip impingement (FAI).

What the AP pelvis X-ray shows

When I evaluate a painful hip, I get an AP pelvis X-ray — a single view that captures both hips at once. That's a real advantage: while we're assessing the hip that hurts, we get a clear look at the other side too. On that film I'm looking at:

From these measurements I can tell you a lot about both hips — including a realistic sense of what the other side looks like today.

The X-ray guides — but how you feel decides

This is the part I most want patients to understand: we treat people, not X-rays. The film is a guide, not a verdict.

• I've seen hips that look severely bone-on-bone on X-ray in patients who have little or no pain.
• And I've seen moderate-looking arthritis in patients who are on crutches and can barely walk.

So a bad-looking second hip on X-ray doesn't automatically mean surgery, and a moderate one isn't automatically left alone. The decision comes down to your pain, function, and quality of life — see the signs it may be time for a hip replacement.

How I approach a patient with two hips in question

My general approach is straightforward and individualized:

When both hips are badly arthritic and painful, I stage the two operations roughly four weeks apart rather than doing them together — for the reasons I explain in double (bilateral) hip replacement. And if only one hip is symptomatic, there's no need to rush the other — we simply monitor it and act if and when it starts limiting you.

Can we predict when the other hip will go?

Honestly, no — not precisely. Arthritis progression is unpredictable. A second hip might become a problem in six months, or it might take many years; some never need surgery at all. Certain diagnoses tend to progress faster than others, which is part of why the underlying cause matters so much. Rather than guess, we monitor — and let your symptoms and function tell us when (or whether) it's time.

From Dr. Harb

Every patient is unique, and so is every hip. Because I take an AP pelvis X-ray, I can usually give you an honest read on both sides from your very first visit — but I'll never push surgery on a hip that isn't bothering you, no matter how it looks on film.

If one or both hips are keeping you from the life you want, that's a conversation worth having. Learn more about hip replacement with Dr. Harb and how long modern hip replacements last, or request a consultation when you're ready.