Hip Replacement Risks and Complications: What Can Go Wrong

For most people a hip replacement is one of the safest major operations there is, with serious complications affecting only a small minority: roughly 1 to 2 in 100 for dislocation and about 1 in 100 for deep infection. I have set the risks out plainly here, because in the weeks before mine I went looking for exactly this and found either reassuring vagueness or frightening forums, and very little in between.

What follows is the list of things that can go wrong, with the real numbers, ordered from the ones you are most likely to be warned about to the rare ones. None of this is meant to scare you off. It is meant to let you walk in knowing what the consent form actually means.

Dislocation: the early risk to respect

Dislocation is the complication surgeons most often warn about, and it sits at about 1 to 2 in 100 ¹. It means the new ball slips out of the new socket, and it is most likely in the first weeks while the muscles and capsule around the joint are still knitting back together.

This is the whole reason for the movement precautions you will hear about, which are commonly advised for the first 6 to 12 weeks after a posterior approach. For me that meant not bending past 90 degrees at the hip, not crossing my legs, and not twisting my upper body over a planted foot. I will admit the first time I dropped a sock on the floor I just stared at it. The surgical approach matters here too: the posterior, anterior, and lateral routes each have trade-offs, and none is clearly best for everyone. If you are prone to forgetting rules, say so, because the team can factor that in.

Infection: uncommon but taken seriously

Deep infection of the joint happens in about 1 in 100 cases, and it is the complication teams work hardest to prevent ². It is serious because it can need further surgery and a long antibiotic course, sometimes including removing and replacing parts of the implant.

The defences are routine and you will see most of them: a dose of antibiotics just before the skin is opened, a sterile theatre and the surgical safety checklist the World Health Organization promotes, and careful wound care afterward. My part was simple but real: keep the dressing dry, watch for spreading redness, fever, or fluid leaking from the wound, and call rather than wait. Most wound redness is nothing. The point is that you do not have to decide that yourself.

Blood clots: guarded against from day one

Blood clots are a recognised risk of any major lower-limb surgery, because the leg is still and the body is in a clot-prone state after an operation. A clot in the leg is a deep vein thrombosis (DVT); one that travels to the lungs is a pulmonary embolism (PE), and together these are called venous thromboembolism (VTE).

The reason you are made to get up and walk the same day or the day after is partly this: movement is one of the best clot preventers there is ³. On top of that you will usually have blood thinners and compression stockings or calf pumps. The symptoms to report quickly are a swollen, hot, painful calf, or sudden breathlessness and chest pain. I kept the ward sheet that listed these by my bed at home for the first fortnight.

Leg-length difference

A small difference in leg length is common after hip replacement, and a noticeable one is uncommon. Often the difference is partly an illusion that settles as you straighten up over the weeks and the long-tightened muscles relax. When mine first came up I was convinced one leg was longer; six weeks on, walking evenly, I could not tell at all.

If a real difference remains and bothers you, a shoe insert usually corrects it simply. The surgeon plans the implant sizing and position specifically to keep any difference as small as possible, so it is worth raising in your pre-operative questions.

Wear, loosening, and needing it done again

Over a long timeframe the main thing that can go wrong is the implant wearing or loosening, which is the chief reason a hip might one day be revised. This is a years-and-decades risk, not an early one. Around 90 to 95 percent of hip replacements are still in place at 10 years, about 6 to 8 in 10 are still working at 25 years in large pooled studies, and many last 15 to 25 years or longer ¹. Satisfaction sits around 9 in 10, higher than for knee replacement.

That is why follow-up continues even when you feel completely well: an X-ray can show early wear before you feel anything. If you are younger when you have it, as I was at 58, the conversation about possibly needing a second one later in life is a normal and sensible one to have early.

The rarer complications

A handful of complications are genuinely uncommon but belong on the list. Injury to a nerve or blood vessel near the hip is rare. A fracture of the bone around the implant during or after surgery is uncommon. Ongoing pain without a clear cause is unusual, given the operation is one of the most effective in modern surgery for relieving arthritis pain. And as with any general or spinal anaesthetic, there are small anaesthetic risks your anaesthetist will discuss with you on the day.

It helps to hold two things at once. These risks are real and worth understanding, which is why the conservative options like exercise, weight management, and pain relief are tried first before surgery is offered ⁴. And the odds are firmly in your favour: most people come through with excellent, lasting pain relief and a hip that eventually feels like their own again. Mine does.

If you take one thing from this, let it be that the early precautions are not fussiness. They are how you spend the first weeks on the right side of those numbers.

This is general information from my own experience and reading, not medical advice. Your risks depend on your health and your hip, so discuss them with a qualified clinician who can examine you.