The human impact of metal hypersensitivity in joint replacement surgery

min watch

The human impact of metal hypersensitivity in joint replacement surgery

The human impact of metal hypersensitivity in joint replacement surgery

There are countless stories of hip replacements and knee replacements being transformational to a person’s quality of life after years of being held back by joint pain. Whilst the majority are successful, worldwide, it is estimated that between 10%-20% of the procedures are being carried out again because original implants have failed.[i] Here we explore the human impact of a joint replacement going wrong.


The issue of allergic reactions to joint replacements

Research shows that 44% of failed knee replacements have been caused by metal hypersensitivity. [ii]Also known as an allergic reaction to the choice of metal used during the procedure; unfortunately, to date, it has been difficult to determine if the patient could have signs of metal hypersensitivity.


We spoke to a retired nurse who, having received a hip replacement, said “I experienced terrible pain which was constant and got in the way of enjoying my retirement. Investigations showed that I’d had a bad reaction to the metal prosthesis used in the replacement and that I’d need to have the prosthesis replaced.” When the patient learns they have metal hypersensitivity after their procedure, they are already experiencing this agonising pain combined with the distress of being along surgery waiting list.


It was a big shock to hear I’d need to go under the knife all over again, but the pain was horrendous, so it felt like it was the only option.”


Impact on caregivers

There are knock-on effects for the patient’s loved ones too. Relatives suddenly become around-the-clock carers. The Royal College of Surgeons reported that, in the aftermath of COVID-19, waiting lists are even longer than pre-pandemic. Figures suggest that up to 16,225 people wait beyond two years for knee or hip replacements.[iii] In the two years that can follow, caregivers spend time advocating for their loved ones; desperately wanting to be given solutions to the problem. An immense amount of pressure mentally – is placed on the caregiver as they live through their relative’s pain, often feeling helpless.


One patient’s caregiver described the period between the failed surgery and revision as ‘a living hell’.


Orthotype can reduce the burden of joint replacement surgery on patients and the NHS

ExplantLab has launched the Orthotype tests that give the patient knowledge of their risk of metal hypersensitivity pre-and post-replacement surgery. Using next-generation genetic sequencing, the tests identify genetic markers in the patient’s saliva or blood samples for specific variations of HLA genes which, if found, indicate patients will develop an adverse reaction to the cobalt chrome that can cause replacement complications. The test results can help ensure optimal implant selection so that they are well-tolerated the first time around, which reduces the need for post-operative chronic pain management or additional surgery down the line. Sally, aged 66 decided to use one of the Orthotype tests to prepare for her upcoming knee replacement, “Having this information is empowering because my doctor can use it to choose the best kind of implant for me, which makes me feel a lot more confident about having the surgery.” Sally is just one example of how we hope to achieve better outcomes for patients as well as helping to ease the waiting times for joint replacement surgery.  


Mr Jeremy Latham, Consultant Orthopaedic Hip Surgeon in Southampton, said: “We know that the majority of patients have an excellent outcome following joint replacement surgery.  However, some people do experience an adverse reaction to implants that are made from cobalt chrome alloy. The use of Orthotype will help us identify these patients so that we can make better decisions about the best implant for them. In the age of personalised medicine and shared decision-making, this is the type of innovation that we should be adopting in orthopaedics.”


Read more about Orthotype at

[i] Akil S, et al. Metal hypersensitivity in total hip andknee arthroplasty: Current concepts. J Clin Orthop Trauma. 2018Jan-Mar;9(1):3-6. doi: 10.1016/j.jcot.2017.10.003. Epub 2017 Oct 10.


[ii] Ng VY, Lombardi AV Jr, Berend KR, Skeels MD, Adams JB.Perivascular lymphocytic infiltration is not limited to metal-on-metalbearings. Clin Orthop Relat Res. 2011 Feb;469(2):523-9. doi:10.1007/s11999-010-1570-7. PMID: 20878289; PMCID: PMC3018196.


[iii] The Royal College of Surgeons: More than 2 millionpeople waiting longer than the statutory 18 weeks for NHS treatment. Accessed Oct 2022.