The University of Southampton

Author: Amelia Hikin

Learning From My Nan – Hip Replacements

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In 1992, my nan received a “simultaneous bilateral total hip replacement”, meaning both hips were replaced during the same surgery. The surgeon had only performed this type of surgery once before her, as this was a newer type of surgery in the UK. She’s had a total of 4 hip replacements, 2 on each hip, all of which were metal-on-polyethylene implants. Unfortunately, she’s suffered from numerous complications both in and out of surgery.

First of all, both hips were cemented in. I wasn’t sure why this decision was made, so I was encouraged to investigate the pros and cons of cemented hips, which I’ve summarised into the table below [1].

Cement ProCement ConCementless ProCementless Con
Cement holds the implant to the bone

Faster Recovery
 
Hardens fast
 
Mouldable material so well fixated
 
Good for those with bone strength issues (osteoarthritis)
Can crack
 
Some people are allergic, which you would only discover after getting the implant
 
If allergies exist, the implant must be completely removed and redone, extending recovery time		Bone grows into the implant
 
Stronger connection
 
No concern over cement in the body
 
Lasts longer than cemented on average


Long recovery as bone needs time to grow into the implant
 
Longer and more difficult rehabilitation






My nan was in her 50s at the time of the operation. A cementless implant would be a favourable choice for someone her age, especially considering cementing hips in makes replacing them later more difficult. However, the reason she was having her hips replaced was due to having level 4 osteoarthritis in her hips, so her bones may not have been strong enough for a cementless replacement. Unfortunately, her left hip had dislocated 3 months after the operation. This meant more bone had to be removed to replace the dislocated hip.

Image showing pulmonary embolism in the lung, labelled as “blockage” (Image modified from [2])

After the operation, they insisted she stay in the hospital for a few days. This saved her life, she proceeded to suffer from a pulmonary embolism (see image to left). This is when a blood clot blocks a blood vessel in your lungs and can be fatal if not treated quickly. They proceeded to find numerous clots throughout her body as a complication of the surgery.


Simultaneous hip replacements have a higher risk of blood clots compared to staged replacements due to the increased time on the operating table [3]. The increased risk of complications means this surgery is typically saved for younger patients in good health. However, simultaneous hip replacements have their advantages, as you only need to enter the operating room once. This means only one dose of anaesthesia, shorter overall recovery time and is less expensive than staged operations [4].

Diagram showing standard polyethylene (left) and cross-linked polyethylene (right) (Modified from [6])

Implants have seen drastic improvement since my nan’s surgery, especially for polyethylene. While 3-4mm of polyethylene is still used, the standard polyethylene wears 0.2mm annually, meaning after 15-20 years, the polyethylene would be completely worn away [5]. The new cross-linked polyethylene only wears 0.04mm annually, meaning it’d take over 75 years to wear [5]. This allows younger patients to get their hip replacements sooner without worry of needing another replacement. The cross-linked polyethylene is more robust due to the additional bonding between chains, which we can see in the diagram to the right. This allows patients to perform high-demand activities after surgery without increasing further complications. If my nan had access to cross-linked polyethylene, she might not have dislocated her new hip nor needed any further hip replacements.

My nan’s hips have once again degraded, but as she is now in her 90s, she’s too old to be operated on again. However, with materials and technology used in hip replacements rapidly advancing, we are getting closer to prosthetics that won’t need replacing. The next generation will have access to safer and more efficient surgeries thanks to her and the millions of others who have undergone joint replacement surgeries.

References

[1] El_Paso_Manual_Physical_Therapy. YouTuber [Video]. 2023 21/09/2023 [accessed 25/03/2024]; Available from: https://youtu.be/OvWXltT6zoU?si=gGals_WT9svuWXON.

[2] Lear, S. Can Pulmonary Embolism Cause PH? Lung Sounds and More. 2023  [accessed 25/03/2024]; Available from: https://www.myphteam.com/resources/can-pulmonary-embolism-cause-ph-lung-sounds-and-more.

[3] Zhang, Z.-h., et al., Risk factors for venous thromboembolism of total hip arthroplasty and total knee arthroplasty: a systematic review of evidences in ten years. BMC Musculoskeletal Disorders, 2015. 16(1): p. 24.

[4] Yale Medicine, Simultaneous Bilateral Total Hip Replacement. [accessed 25/03/2024]; Available from: https://www.yalemedicine.org/conditions/simultaneous-bilateral-total-hip-replacement.

[5] Andrew_Yun_MD. YouTube [Video]. 05/11/2021 [cited 25/03/2024]; Available from: https://youtu.be/IQloOIiZvQI?si=2_R-vfoO24C85Kkk.

[6] Thomas, J., M.E. Thomas, and S. Thomas, Crosslinked Polyethylene: State-of-the-Art and New Challenges, in Crosslinkable Polyethylene: Manufacture, Properties, Recycling, and Applications, J. Thomas, S. Thomas, and Z. Ahmad, Editors. 2021, Springer Singapore: Singapore. p. 1-15.

I’ve linked further reading to key words – these will aid in understanding and provide some context. I really recommend checking out the YouTube video embedded to cross-linked polyethylene!

Waiting for a knee replacement

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Photo of Doctor holding a post-op knee

My dad, along with almost 400,000 others, has been waiting for a knee replacement on the NHS for over a year [1]. This wait has caused numerous complications for him, as originally he was only going to need a partial knee replacement. Now a full knee replacement is required, which will drastically increase recovery time, pain levels, complications and the cost of the procedure on the NHS [2].

Partial knee replacements have been shown to improve quality of life and could of saved almost £2000 on the NHS over my dad’s lifetime if they acted sooner [2]. If we were to go private, a full knee replacement would cost around £14,000 [1]. This amount of money is unfeasible for a lot of UK citizens, especially since the cost-of-living crisis. But for those who cant pay up, they have to suffer with degradation of health and lifestyle.

Image showing partial knee (left) and total knee (right) replacement https://www.drsantoshshetty.com/partial-vs-total-knee-replacement/ (accessed 11/03/2024)

Knee replacement surgery is rapidly developing, but is only accessible to those paying privately. By choosing NHS, you will lose access to using CT Scans to create 3D images of the patients knee, having assisting robotics in surgery and less invasive procedures. All of these have the potential to decrease recovery time and increase surgery success [1]. I believe the NHS should offer a partial payment service for those undergoing knee replacement, as some individuals who cannot afford £14,000 for private may still like to pay extra for more modern materials or procedures in order to increase their quality of life. This offers more balanced healthcare across those with different incomes and allows all individuals to have a say on how they want their body to be treated.

Day-to-day life becomes much more difficult; walking is a challenge, so chores around the house become an impossible task. Some individuals may even need to take time off work or find a new job entirely. Exercising can also become difficult, which may lead to weight gain. However increased weight leads to more pressure on the knee, creating higher levels of pain and will make recovery even harder after surgery.

Knee issues can be incredibly isolating and have a massive impact on mental health. It’s important to note how much waiting lists impact mental health. My dad has stated that the stress and pain that he’s gotten from his knee has worsened his heart condition – yet another issue that has arisen from having to wait. He’s also unable to play with his grandsons, as even getting onto the floor is an impossible task.

Treating patients for knee pain also becomes difficult with long waiting lists. Knee pain is excruciating, but there are no pain killers that are designed to be taken for moderate-severe pain daily for over a year.  This limits any help to only walking stick and physio exercises in the hopes of reducing pain.

Current NICE Guidelines state that adults should be allowed a choice between partial and full if both options are suitable [3]. But with increasing waiting lists, the “choice” is made redundant. With no end in sight, my dad’s knee will continue to degrade, leaving him with increasing pain with each passing day.

Recommended watch – Dame Judi Dench’s story on her total knee replacement

References:

1.           Knee Replacement Surgery in 2023: Should you Stick with the NHS or go Private? 2024  11/03/2024]; Available from: https://www.thebestofhealth.co.uk/health-conditions/consultants-specialists/how-much-does-knee-replacement-surgery-cost-in-the-uk/.

2.           Burn, E., et al., Cost-effectiveness of unicompartmental compared with total knee replacement: a population-based study using data from the National Joint Registry for England and Wales. BMJ Open, 2018. 8(4): p. e020977.

3.           Joint replacement (primary): hip, knee and shoulder. 2022, NICE Quality Standard 206.