Risks of Shoulder Replacement Surgery 'Underestimated'

Liam Davenport

February 21, 2019

The risks associated with shoulder replacement surgery are higher than previously assumed, particularly for younger patients and those aged 85 years and over, say UK researchers who urge clinicians to make the potential for harm made clearer to patients before they undergo the procedure.

The researchers, from the University of Oxford, looked at hospital episode data on more than 58,000 procedures performed between 1998 and 2017, finding that the annual number of operations increased more than five-fold.

The data indicated that the lifetime risk of surgical revision of the implant was highest in men aged 55–59 years, at 1 in 4 cases, while it was lowest in women aged 85 years and older.

However, both women and men in the 85 and over age group had far higher risks of serious adverse events at both 30 days and 90 days post-surgery than younger patients.

Male Risks and Comorbidities

The research, published by The BMJ on 20th February, showed that being male and having comorbidities also predicted a higher risk of serious adverse events.

They team writes: "All younger patients, particularly men, need to be aware of the high likelihood of early failure of their implant and the need for further and more complex revision replacement surgery."

They add that with the ageing population, the demand for shoulder replacement surgery in older patients will continue to increase.

"The alarmingly high rates of adverse events in elderly patients with comorbidities suggests that better approaches to patient selection, preparation, and postoperative care might be required."

The researchers continue: "The high risk of adverse events described here should form part of shared decision making with patients."

"The risk levels in this study are higher than previously considered byclinicians. Patients need to be informed of these levels and carefully counselled about the potential risks of serious adverse events."

Low Perceived Risk

The study was led by Dr Richard Craig, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford.

He told Medscape News UK that the risks of shoulder replacement surgery and upper limb surgery in general "have been perceived to be much lower than other orthopaedic joint replacement operations for hip and knee arthritis".

"Our study shows that, whilst for most patients having shoulder replacement surgery the risks are relatively low, they are higher than previously considered."

He noted that, although the risk of blood clots after shoulder replacement surgery is lower than that for hip or knee replacement, "the chance of some other complications is actually similar".

Dr Craig added: "With regard to the risk of revision surgery, the trend of higher risks of revision in younger patients is similar to studies of the hip and knee, which actually find even higher rates for the under 60s.

"However, overall, shoulder replacements do not currently last as long as hip or knee replacements."

He said: "We hope that patients and surgeons will find our study useful in helping them decide whether to proceed with surgery."

Increase in Procedures

The authors note that studies have shown that primary shoulder replacement surgery offers early improvements in shoulder specific and overall quality of life.

This has led to an increase in the number of procedures performed and the rapid adoption of novel implant technologies.

However, they point out that "no large scale trials and very few published studies have been carried out on the long-term outcomes across different age groups, including the risks of revision surgery".

To investigate further, they gathered hospital episode statistics from the National Health Service (NHS) on all patients aged at least 50 years who underwent primary elective shoulder replacement surgery between 1998 and 2017.

They identified 58,054 procedures performed in 51,895 patients during the study period, with 6159 individuals undergoing bilateral surgery.

The mean age at primary surgery was 72.2 years, and 42,080 (72%) of the procedures were performed on women.

The most common indication for shoulder joint replacement was osteoarthritis or rotator cuff tear arthroplasty, which accounted for in 39,835 (69%) procedures, followed by inflammatory or other conditions, previous trauma, and osteonecrosis.

The number of procedures performed annually increased from 1018 in 1998 to 5691 cases in 2016, representing a 5.6-fold increase over the study period.

Serious Adverse Events

The rate of serious adverse events, including pulmonary embolism, myocardial infarction, lower respiratory tract infection, acute kidney injury, urinary tract infection, cerebrovascular events and all cause death, was 3.5% at 30 days and 4.6% at 90 days.

However, the team found that the risk of serious adverse events at 30 days and 90 days increased with increasing age.

In men, the 30-day incidence of serious adverse events increased from 1.6% among those aged 50–64 years to 17.4% in men aged at least 85 years, while the 90-day incidence increased from 2.1% to 21.2%.

In women, the 30-day incidence increased from 1.6% in those aged 50–64 years to 9.1% in those aged 85 years and over, while the 90-day incidence increased from 2.2% to 11.2%.

The results also showed that, among women aged 50–64 years, the relative risk of pulmonary embolism compared with baseline was 61 on days 0–30, and 28 for the first 90 days post-surgery.

Overall, the risk of dying from any case within 90 days of surgery was 0.47%.

Compared with baseline population mortality rates, the relative risk of all-cause mortality at 30 days following shoulder replacement surgery was 0.93, and was 0.63 at 90 days.

Logistic regression analysis revealed that age, sex, and Charlson comorbidity index scores were all significant predictors of serious adverse events at 30 and 90 days.

In all, 3891 implants required revision, with 456 revisions proceeded by another reoperation. The indication for revision or reoperation was infection in 10.7% of cases.

The lifetime risk of implant revision ranged from 2.7% in women aged 85 years and over to 23.6% in men aged 55–59 years, with the highest risk in the first 5 years after surgery.

Overall, revision-free implant survival rates were 90% at 10 years and 87.8% at 18 years post-surgery.

Need for Better Monitoring

The team writes: "Revision shoulder replacement surgery is complex, challenging, and with greater risk, and so surgeons often encourage patients to live with shoulder disability and a failing implant.

"As such, revision rates might not be fully reflective of the true failure rates, which are likely to be higher, and the burden of patients living with an unsatisfactory shoulder replacement is largely unknown."

They add: "As future innovation will undoubtedly increase the possibilities of treatment for both younger and older patients, a pressing need remains to monitor serious adverse events and revision rates and develop prediction tools to help identify those patients most likely to benefit from surgery, while minimising such adverse events, revision surgery, and further healthcare costs."

This research was supported by the National Institute for Health Research Oxford Biomedical Research Centre. Jennifer C. E. Lane is a Versus Arthritis research fellow, and Craig is a Royal College of Surgeons/National Joint Registry research fellow.

No conflicts of interest declared.

BMJ 2019; 364: l298. doi:10.1136/bmj.l298


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