A hip replacement is designed to closely mimic the function of a natural, healthy hip. However, there are some differences in the strength and mechanics between a hip replacement and a natural hip joint.
How strong is a hip replacement compared to a natural hip?
A hip replacement is quite durable and strong, allowing patients to maintain an active lifestyle. However, it does not quite match the strength and weight bearing capacity of a healthy natural hip.
There are a few reasons why a hip replacement may not be quite as strong as a natural hip:
- The materials used in a hip replacement – titanium and plastic – are not as strong as bone and cartilage.
- The junction where the ball (femoral head) attaches to the thigh bone stem is prone to wear and loosening over time.
- Without ligaments holding it in place, there is slightly more movement and micro-instability in a hip replacement.
Despite this, modern hip replacements using metal-on-plastic or ceramic-on-ceramic bearings can last 15-20 years or longer before wearing out in most patients. With proper precautions and activity modifications, an artificial hip can provide excellent function.
What materials are used in hip replacements?
The components used in a total hip replacement include:
- Ball and stem: Made of a cobalt-chromium alloy or ceramic material that attaches to the top of the femur (thigh bone).
- Socket: Made of titanium or titanium alloy with a plastic (polyethylene), ceramic, or metal liner.
The femoral stem is secured inside the thigh bone while the socket component is fixed into the pelvic bone. The ball portion then articulates against the socket liner to recreate hip joint movement.
Common types of hip replacement bearings:
- Metal-on-plastic: Cobalt-chromium ball with plastic (polyethylene) liner. Most common.
- Ceramic-on-plastic: Ceramic ball with plastic liner. Used in younger more active patients.
- Ceramic-on-ceramic: Ceramic ball and socket pairing. Very low wear but risk of fracture.
- Metal-on-metal: Not used much anymore due to high failure rates.
What is the average lifespan of a hip replacement?
With proper surgical technique and using modern bearing surfaces, a total hip replacement is expected to last 15-20 years or longer before needing to be replaced again (revision surgery).
Some key factors affecting lifespan of a hip replacement include:
- Age of patient at the time of surgery
- Activity level and impact on the joint
- Type of bearing surfaces used
- Surgical skill and technique
- Patient’s bone quality
In many cases, if the components are well fixed, only the plastic liner or ball portion may need to be changed out instead of the entire prosthesis during a revision surgery.
What activities can you do with a hip replacement?
Most patients with a hip replacement can return to relatively normal daily activities including:
- Climbing stairs
- Light household chores
- Yoga or tai chi
While hip replacements allow an active lifestyle, doctors typically advise avoiding high impact activities to preserve the longevity of the prosthesis. High impact sports such as jogging, football, hockey, basketball may put too much strain on the implant.
Activities requiring heavy lifting or repetitive hip twisting are also discouraged to protect the hip replacement from mechanical wear or loosening.
What are the risks or complications of hip replacements?
As with any major surgery, there are some risks involved with hip replacement surgery. These include:
- Infection – Occurs in about 1-2% of patients
- Dislocation – The ball can dislocate from the socket in 2-5% of cases
- Component loosening – Implant parts can loosen over time in 5-10% of patients
- Bone fracture – Periprosthetic fracture around the implant occurs in less than 3% of cases
- Nerve injury – Injury to nerves around the hip occurs rarely
- Leg length discrepancy – Legs may be slightly different lengths after surgery
- Chronic pain – Some patients have persistent hip pain after surgery
With newer techniques such as minimally invasive surgery, many of these complications occur less frequently than in the past. Overall, complication rates are relatively low with hip replacements.
How painful is recovery from hip replacement surgery?
Patients generally experience the most pain within the first 1-2 weeks after a hip replacement as the surgical trauma is healing. Pain then gradually improves over 6-12 weeks once the tissues have healed.
Medications are prescribed to keep patients comfortable, including:
- Narcotic pain medications for the first 1-2 weeks
- Anti-inflammatory medications
Utilizing new minimally invasive surgical techniques, many patients experience less pain and faster recovery compared to traditional open hip replacement procedures. Enhanced rehabilitation protocols also help patients regain mobility faster while managing discomfort.
Most patients are able to move the hip joint soon after surgery to prevent stiffness. Although uncomfortable at first, early mobilization improves outcomes. Complete pain relief can take 3-6 months.
How long does it take to recover after hip replacement surgery?
The recovery timeline after a hip replacement is:
- 1-2 days hospitalization – Patients are monitored post-operatively before being discharged
- 1-2 weeks – Dependence on walker or crutch to assist with walking
- 2-4 weeks – Gradual increase in activities with transition to cane
- 6 weeks – Driving allowed depending on recovery progress
- 12 weeks – Resume light athletic activities
With newer tissue-sparing surgical techniques, many patients are able to bear full weight and walk without any assistive device around 4-6 weeks after surgery. Complete recovery can take 3-6 months.
Physical therapy is vital after hip replacement for regaining strength and mobility. Recovery is highly variable, as some patients may return to normal function sooner while others take more time.
How long does a hip replacement procedure take?
The surgery to replace the hip joint takes 1-2 hours in most cases. However, patients should plan to be at the hospital or surgical center for around 4-6 hours from check-in to discharge for the full procedure.
The main steps and time estimates include:
- Anesthesia and prep – 30-60 minutes
- Incision – 15-30 minutes
- Removing old hip joint – 30-60 minutes
- Inserting new components – 30-60 minutes
- Closing incision – 30 minutes
- Recovery from anesthesia – 1-2 hours
Minimally invasive hip replacement may take slightly less time. Surgeon’s experience and complexity of the case can also affect the length.
In summary, a hip replacement provides excellent function and allows return to an active lifestyle. However, even the highest quality hip replacements cannot fully match the strength, stability, and mechanics of a natural healthy hip joint.
With proper technique and materials, a hip replacement typically lasts 15-20 years or more before needing revision. Avoiding high impact activities helps prolong the lifespan of a hip replacement. While not identical to a natural hip, a hip replacement is still a very functional option for patients suffering from painful hip arthritis.