A partial hip replacement, known medically as a hemiarthroplasty, typically lasts 10 to 15 years or longer. In one study of women over 70, 94% of implants were still functioning well at both the 5-year and 10-year marks, with 98% surviving the first year. How long yours lasts depends on your age, activity level, the condition of your cartilage at the time of surgery, and how the implant interacts with your natural hip socket over time.
What the Survival Numbers Look Like
Unlike a total hip replacement, which swaps out both the ball and the socket, a partial hip replacement only replaces the ball (the femoral head). The socket side of the joint keeps its natural cartilage. This distinction matters because the metal or ceramic ball now moves against living tissue instead of a manufactured liner, and that’s the main factor determining how long the implant holds up.
The good news is that most partial hip replacements perform well for years. A study tracking prosthesis survival in elderly women found a 94% survival rate at 10 years. That number stayed flat between years 5 and 10, meaning most failures happened relatively early rather than gradually increasing over time. For patients in their 70s and 80s, many will never need a revision surgery in their lifetime.
Comparing partial to total hip replacement, a large randomized trial published in the New England Journal of Medicine found nearly identical rates of secondary procedures within two years: 8.3% for partial replacements and 7.9% for total replacements. The types of complications differed, though. Total hip replacements were more than twice as likely to dislocate (4.7% vs. 2.4%), while partial hip replacements more often needed implant revision. Overall function and quality-of-life scores were similar between the two groups.
How a Partial Hip Replacement Wears Out
The weak point of a hemiarthroplasty is the natural cartilage lining your hip socket. Over time, the metal ball can erode that cartilage, gradually narrowing the joint space and eventually wearing into the bone underneath. This process, called acetabular erosion, is the most common reason a partial replacement eventually needs to be converted to a total hip replacement.
A retrospective study of nearly 2,500 hemiarthroplasty cases found that when acetabular erosion does cause pain, it tends to show up sooner than you might expect. The average time to symptomatic erosion was about 25 months, but half of all painful erosion cases appeared within the first 6 months. Radiographs in some patients showed progressive narrowing of the joint space as early as 6 to 18 weeks after surgery. This suggests that the condition of your cartilage at the time of surgery plays a major role. If the socket cartilage is already damaged before the implant goes in, erosion can accelerate significantly.
Not everyone who develops some cartilage wear becomes symptomatic. Many patients show mild joint-space narrowing on X-rays but experience no pain. Symptomatic erosion requiring conversion to a total hip replacement remains relatively uncommon across the full population of hemiarthroplasty patients.
Why Some Implants Fail Earlier
When partial hip replacements do fail, the reasons fall into a few categories. Data from revision hip surgeries shows the most common causes of failure:
- Loosening without infection (23%): the implant gradually loses its bond with the surrounding bone
- Dislocation (22%): the ball slips out of the socket, sometimes repeatedly
- Infection (22%): bacteria colonize the implant, which can happen weeks or years after surgery
- Mechanical complications (6%): problems with the implant components themselves
- Bone fracture (4%): a break in the bone around the implant, often from a fall
Loosening, dislocation, and infection each account for roughly equal shares of failures. Loosening tends to develop gradually over years, while dislocation and infection can happen at any point. Falls are a particular concern for elderly patients because a fracture around the implant stem often means a more complex revision surgery.
How Activity Level Affects Implant Wear
Implant wear is driven by use, not simply by the passage of time. Every step you take is one more cycle of the ball moving against the socket. Research tracking hip replacement patients found a massive range in daily activity: some patients took about 1,000 steps per day while others logged over 13,000, a 13-fold difference. That translates to anywhere from roughly 180,000 to 2.4 million movement cycles per year.
Activity levels tend to drop naturally with age. Patients aged 55 to 69 averaged about 4,900 steps per day (roughly 890,000 cycles per year), while those 70 and older averaged around 3,400 steps per day (about 630,000 cycles per year). This natural decline in activity is one reason partial hip replacements often last longer in older patients. Their implants simply accumulate fewer total cycles.
Interestingly, one study found no clear statistical link between individual activity levels and measured wear on the socket liner in total hip replacements, suggesting that other factors like implant materials and surgical positioning also matter. Still, the general principle holds: more movement means more wear over time, and this is especially relevant for partial replacements where the socket side is natural cartilage rather than engineered plastic.
Protecting Your Implant Long-Term
The activities you choose after surgery can influence how long your implant lasts. Rehabilitation guidelines from major orthopedic centers recommend sticking with lower-impact activities: swimming, walking, golf, cycling, dancing, and doubles tennis. These keep you mobile and strong without subjecting the joint to repetitive high forces.
Higher-impact activities like jogging, soccer, basketball, and football are generally discouraged because they create large, repeated loads on the joint and increase the risk of falls. Twisting and torque forces on the hip are also worth avoiding, as they stress the bond between the implant and bone and increase dislocation risk.
Strengthening the muscles around your hip through consistent, guided exercise helps stabilize the joint and distribute forces more evenly. Patients who maintain good muscle tone and balance are less likely to fall and less likely to experience dislocation, both of which are common reasons for early revision. Keeping your weight in a healthy range also reduces the load your implant bears with every step, effectively slowing the accumulation of wear cycles.
When a Partial Replacement Needs Revision
If a partial hip replacement does wear out, the typical next step is conversion to a total hip replacement. This involves removing the existing implant stem (if it has loosened) or keeping it in place (if it’s still well-fixed) and adding an artificial socket liner. The surgery is more complex than the original procedure, and recovery tends to take longer.
The signs that a revision may be needed include increasing groin or thigh pain that wasn’t present in the months after your original surgery, a feeling of instability or catching in the hip, and progressive difficulty walking. X-rays can reveal joint-space narrowing, implant loosening, or bone erosion around the socket. Not all of these findings require surgery, though. Many patients with radiographic changes remain comfortable and functional, and the decision to revise is based primarily on symptoms and quality of life rather than imaging alone.