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The definition of a successful total knee replacement differs for Asian and European patients
Current outcomes and quality of life assessments do not consider cultural variations.
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by Bharat S. Mody, MS(Orth), MCh(Orth)
Total knee arthroplasty is widely acknowledged to be one of the most successful procedures in orthopaedic practice. Numerous long-term studies attest to the significant improvement in quality of life after TKA procedures, according to a report in 2003 by the Agency for Health Care, Research and Quality.
During the past 3 decades, numerous outcomes measurement instruments have been formed to quantify and calibrate the results of total knee arthroplasty (TKA) procedures. However, these instruments are of Western origin and do not capture the aspirations of many population segments of the world. Perhaps, the reason for this is that TKA was initially developed and widely deployed in Western countries.
Recently, however, this procedure has become increasingly accepted in many Asian countries and is rapidly gaining momentum. This increase is due to the rapid growth of these countries’ economies; their populations are now able to afford this relatively costly and advanced medical procedure.
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India is a classic example of this phenomenon. The last population census of India, conducted in 2001, showed that the number of people older than 65 years had increased by 29% during the previous decade.
Explosive growth of TKA procedures
Further, prevalence of radiographic knee osteoarthritis (OA) in the Indian population older than 60 years is estimated to be 43% in women and 25% in men. The prevalence of symptomatic knee OA is estimated to be 15% for women and 5% for men. The age spectrum is also significantly biased towards the younger age in Indian women. With a population of 1.2 billion, it is obvious that in the years to come TKA as a procedure will see explosive growth in numbers in India.
A total of 45,000 TKAs were performed last year in India. During the previous 5 years, the number of TKAs performed in India has increased an average of 30% each year and the same growth rate is expected to continue in the coming 10 years. This translates into more than 350,000 TKAs per year by the end of the decade.
Quality of life measures
These data bring into focus the importance and need to discuss certain issues related to TKA in terms of the needs of the Indian/Asian population.
Outcome measures, in general, are a component of the broad area of health-related quality of life (HRQL) measurement. The most commonly used HRQL measurement is the SF-36 questionnaire, which has been translated and employed in more than 50 countries, as part of the International Quality of Life Assessment Project. The SF-36 is a generic measurement tool, and not specific for post-TKA outcomes. It has a physical health and a mental health component. Within the physical health component, it has the physical functioning scale composed of the following elements:
- vigorous activities;
- moderate activities;
- lift and carry groceries;
- climb several flights of stairs;
- climb one flight of stairs;
- bend, kneel;
- walk a mile;
- walk several blocks;
- walk one block; and
- bathe and dress.
It is interesting to note that there is no mention of activities or postures such as cross-legged sitting, squatting or namaz (traditional Muslim prayer position).
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Image: Mody BS |
Post-TKA outcome measures
Let us now examine the specific outcome measures developed for post-TKA results.
The ideal knee arthroplasty outcome measure system should be applicable to all patients so that genuine comparison can be made between different population groups. The desirability of a universal tool for assessing outcome after joint replacement surgery has been identified as long ago as 1975 by Kettelkamp and colleagues.
In 1994, Drake and colleagues published a systematic review of rating scales for TKA. They identified 34 different rating systems that were published literature between 1972 and 1992.
The rating systems that are most commonly used throughout the world are the WOMAC, Knee Society Score, Oxford Score and Hospital for Special Surgery Score. None of these measuring systems have included cross-legged sitting, squatting and namaz as part of their assessment criteria in the performance of activities of daily living (ADL).
In fact, it is a general perception and has been reported in multiple peer- reviewed journals that patients who undergo TKA subsequently will not be able to achieve high-flexion postures — greater than 120° — such as cross-legged sitting. Perhaps this perception prevails because the vast majority of the Western populations hardly ever adopts these postures.
High-flexion postures are part of the ADL in many Asian cultures. The implant manufacturing industry has already recognized this fact and has begun marketing implants that are supposed to achieve or accommodate high flexion. The cost of these high-flexion implants is significantly higher compared with standard implants. The price difference between the all-polyethylene monoblock tibial component and the metal-backed modular high-flexion tibial component is approximately $600 in India. This is equivalent to an entire year’s income for millions of people in India.
Population-specific needs
It is time the more evolved Western health care systems and the rapidly evolving Asian health care systems collaborate to focus on issues of TKA which are relevant to the specific needs of the Asian population. For example, the general and specific outcome measure instruments should be modified to capture the aspirations related to the ADL of Asian populations.
It is not uncommon for Indian patients to consider their TKA a failure, despite “successful” outcomes measure scores. Although they may have gained relief from pain and they are able to walk a couple of blocks, they cannot perform ADL like cross-legged sitting, which are an integral part of their daily routine. It is the equivalent of telling European patients that their TKA has been successful, despite their not being able to sit on a chair.
We need to examine whether it is possible to evolve methods to achieve high flexion while still controlling the cost of the procedure. I have had the experience of incorporating certain surgical techniques while performing TKA which have given a high percentage of my patient population the ability to perform ADL, such as cross-legged sitting, while still using an all-polyethylene monoblock tibia and a standard femoral component.
The recent establishment of the EFORT Asia Panel can be an ideal vehicle to collaborate and address issues mentioned in this article for the benefit of the global population.
References:
- Drake BG, Callahan CM, Dittus RS, Wright JG. Global rating systems used in assessing knee arthroplasty outcomes. J Arthroplasty. 1994;9(4): 409-417.
- Kettelkamp DB, Thompson C. Development of a knee scoring scale. Clin Orthop Relat Res. 1975;(107):93-99.
- Total Knee Replacement. December 2003. Agency for Healthcare Research and Quality, Rockville, MD.
Bharat S. Mody, MS(Orth), MCh(Orth), is Director and Chief Arthroplasty Surgeon at the Centre for Knee and Hip Surgery at Welcare Hospital, Vadodara, India. He can be reached at centreforkneesurgery@gmail.com.