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Common elective orthopaedic procedures and their clinical effectiveness: umbrella review of level 1 evidence

BMJ 2021; 374 doi: (Published 08 July 2021) Cite this as: BMJ 2021;374:n1511

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How to prove the value of ‘the operation of the century’

Dear Editor

End stage osteoarthritis of the hip is an invalidating disease. Fortunately, for more than 50 years, a total hip replacement had enabled people to be active, productive and independent again. Because of these very good long-term results, the procedure has been coined the ‘operation of the century’ in the Lancet (1). Blom et al. conclude that no strong evidence exists that a total hip prosthesis is superior to non-operative alternatives for end stage osteoarthritis. The authors are technically correct, by the lack of randomised controlled trials into this subject. This conclusion however demands some nuance, as not scientifically proven is not equivalent to not effective.

In this context, the BMJ has previously published on the effectiveness of the use of parachutes during free fall in preventing major trauma or death. A meta-analysis concluded that there was no proper evidence supporting the use of parachutes (2). However, we know from observation that the use of a parachute can significantly withstand gravitational forces, reducing major trauma or death. Likewise, we know from the study of large device registries, that artificial hips joints have a high survival rate, with a low number of adverse events (3). For example, the lifetime risk of requiring revision surgery in patients who had total hip or total knee replacement over the age of 70 years was 5%.

More than 1 million total hip replacements are performed each year worldwide, many of these patients are prospectively followed in arthroplasty registers (4). Revision surgery is the traditional endpoint of device registries. In recent years, clinician-reported outcomes such as adverse events and patient-reported outcome measures [PROMs], are increasingly integrated into the device registry in order to become large patient outcomes registries (5,6). Self-reported satisfaction is 90% after hip replacement surgery (6). In addition, hip replacement is a very cost-effective intervention (4). The cost per quality-adjusted life-year gained with hip replacement is between the reasonable values of $1500 and $10402. Furthermore, arthroplasty may lead to health care cost savings, with a reduction in costs of $278 every year per patient compared with an increase of $1978 every year per matched, non-operated control patient. How much more evidence is needed when real-world evidence, obtained with observational research, is available?

RCTs are considered to produce the highest level of evidence. The internal validity of RCTs is high, although its interpretation for general practice is often limited, considering the ideal circumstances under which RCTs are conducted. For surgical trials randomisation is cumbersome, sometimes inappropriate or even unethical (7). Several practical counterarguments could be made against requiring routine use of RCTs in surgical specialties. Besides the high costs and duration of study (8,9), issues related to homogeneity (8), clinical equipoise (7), blinding (7), and relatively small sample size to identify adverse events (8) are well recognized. Observational research, e.g. comparative research using patient outcomes registry data, is particularly valuable to investigate effectiveness, harms, prognosis, and infrequent outcomes in surgical populations as well as in situations where randomization is not possible (8). Therefore, the FDA nowadays recognises real-world evidence gathered with observational data from large device registries as valid to support regulatory decisions. The yardstick for decision-making should take into account the risks and benefits of local conditions, including broad patient selection and (logistics in) hospitals, in order to enhance generalization. This could be determined from patient outcomes registries. Decision-making should not be restricted to those of an ideal situation, as provided in randomized controlled trials (RCTs).

In conclusion, a total hip prosthesis keeps millions of people mobile and free of pain from an otherwise invalidating disease. As implants have high survival rates and allow most patients to participate in society again, hip replacement is a very cost-effective intervention from a societal perspective. The observational data obtained from device registries that demonstrate these favourable outcomes are increasingly recognised for regulatory decision-making. As Blom et al. briefly mention in their discussion, it seems unnecessary and unethical to study hip replacement under the circumstances of an RCT.

Jetze Visser, MD, PhD
Orthopaedic surgeon
Radboudumc, Nijmegen, the Netherlands

Miranda van Hooff, PhD
Clinical epidemiologist
Radboudumc and St. Maartensclinic, Nijmegen, the Netherlands

Wim Schreurs, MD, PhD
Orthopaedic surgeon
Professor of Dutch orthopaedic implant registration
Radboudumc, Nijmegen, the Netherlands

1. Learmonth ID, Yough C, Rorabeck C. The operation of the century: total hip replacement. Lancet 2007:370;1508-19
2. Smith GCS, Pell JP. Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomized controlled trials. BMJ 2003;327:1459-61
3. Bayliss LE, Culliford D, Monk AP et al. The effect of patient age at intervention on risk of implant revision after total replacement of the hip or knee: a population-based cohort study. Lancet 2017;389:1424-30
4. Ferguson RJ, Palmer AJR, Taylor A et al. Hip replacement. The lancet 2018;392:1662-71
5. Gliklich RE, Leavy MB, Dreyer NA (sr eds). Registries for Evaluating Patient Outcomes: A User’s Guide. 4th ed. Rockville, MD: Agency for Healthcare Research and Quality; 2020.
6. Wilson I, Bohm E, Lubbeke A et al. Orthopaedic registries with patient-reported outcome measures. EFFORT open rev. 2019;4:357-367
7. McGulloch P, Taylor I, Sasako M, Lovett B, Griffin D. Randomised trials in surgery: problems and possible solutions. BMJ 2002;324:1448-51
8. Marko NF, Weil RJ. The role of observational investigations in comparable effectiveness research. Value Health. 2010;13:989-97
9. Concati J, Lawler EV, Lew RA et al. Observational methods in comparative effectiveness research. Am J Med. 2010;123:e16-23

Competing interests: No competing interests

17 August 2021
Jetze Visser
orthopaedic surgeon
Miranda van Hooff, Wim Schreurs
geert grooteplein 10, Nijmegen