Elective total hip arthroplasty in the elderly: Three studies reviewed

Globally, the number of persons aged 80 years and over is projected to increase to more than 425 million by 2050.⁹ Here in South Africa, the exact number of persons over eighty is not known; however, according to StatsSA, the number of people aged 60 years or more is estimated to be 5.42 million, which represents a growth of 3%  for the period 2019- 2020⁹ - an upward trend that is expected to continue.

As populations age, the number and severity of comorbidities evidenced in these older population groups increase. Aside from a dramatic rise in cardiovascular, diabetic and cognitive conditions, the last three decades have seen a rapid rise in the incidence of debilitating musculoskeletal conditions.¹  In the US, osteoarthritis now accounts for most disabilities in their elderly population.¹¹ Indeed, so prevalent is the disease and its sequelae -  such as hip fractures -  that by 2030, the demand for total hip arthroplasty is expected to increase by a staggering 174%.¹¹

Locally, precise data is more difficult to determine. In recent years, various studies have indicated a similar increase in the occurrence of these musculoskeletal conditions in the southern African region as a whole. This is at odds with the commonly held belief that the diseases are a developing country phenomena.^2,5 Paruk et al., in their 2017 study, considered a sample of black patients, aged 60 years and older, who presented at five public hospitals in the eThekwini region with hip fractures.They reported that fractures in this group were tenfold higher than previously recorded. However, it should be noted the study was limited in design – both in sample number and location.⁵  

There are, nonetheless, significant differences between South Africa and countries such as the US and UK. Whereas in the United States, it appears that the increasingly ageing population accounts for the high number of hip fractures and other osteoarthritic complications, here in South Africa, additional drivers such as infectious disease, trauma (and other injuries), and HIV infections are significant contributors to the increase in incidence seen locally.¹ Indeed, as Gregson et al. commented in Lancet Global Health: "Increasing evidence is dispelling the outdated myth that fragility fractures are not a problem in sub-Saharan Africa." ^{2(pg e26)}

Hip arthroplasties are among the most cost-effective surgical interventions when considered in cost per quality-adjusted life-years gained.^3,7 Public health administrators appear to have acknowledged this efficacy. In 2015, the Gauteng Department of Health launched its innovative Move the Walk week at the Helen Joseph hospital in Johannesburg, intended to clear up the surgical backlog of arthroplasties by implementing periodic week-long intense surgical programs in which 25 - 35 arthroplasties are conducted. According to Sekeitto & Aden, this was "…the first documented implementation of standardised procedures for arthroplasty in the public sector." ^7(pg250)

When considered against this background, and taking into account a public healthcare system that caters for 84% of the total population⁷, the magnitude of the problem facing public healthcare administrators, healthcare practitioners and the care system, in general, becomes apparent. For public health programs such as Move the Walk week to be sustainable in a resource-constrained environment, it is imperative to develop standardised protocols to reduce the average and extended lengths of postoperative stay (EPLos) whilst simultaneously mitigating the risk of post-discharge complications. And to develop such protocols, it is necessary to understand what factors contribute to successful outcomes and what factors contribute to the converse, as evidenced in the development of complications resulting in extended stays and readmissions.

Two South African studies by Dlamini et al.¹, and Sekeitto & Aden ³, completed in 2019 and 2021, respectively, sought to address these questions.

In their 2019 paper, Dlamini et al. looked to define the incidence of extended-length of postoperative stay (EPOLS) for patients who underwent primary hip arthroplasty at a quaternary hospital in KwaZulu Natal. The researchers then wanted to determine which "patient-specific, clinical and surgical characteristics" ^1(pg41) contributed to these extended stays. Although not explicitly aimed at the oldest of the old  - only 23% of their sample group was older than 65 - their findings offered valuable insights into what factors should be considered in developing a risk-stratification program for these procedures.¹

Firstly they determined that the median length of hospital stay for an uncomplicated total hip arthroplasty was five days. 28.1% of the patients in this study had stays of greater than seven days, thereby establishing the incidence of EPOLS for participants in their research. The researchers noted that in comparative studies from the UK, Pakistan and US, the median stay was longer – a mean of 7- 8 days. Dlamini et al. hypothesised that this difference might result from the fast-tracking of certain procedures in our resource-constrained environment.  
 

They found three characteristics to be independently associated with EPOLS, namely:

1. Females were five times more likely to experience EPOLS following primary hip replacement

2. There was a correlation between a patient's maximum walking distance preoperatively and their recovery rate. While the researchers could only establish a maximum walking distance for 58.4% of their sample group,  28% of those patients could not walk 100 m or more before their procedure, and all experienced an extended postoperative stay

3. Finally, the length of surgery time contributed to a four-fold increase in the incidence of EPOLS

The 2021 study by Sekietto& Aden⁷ sought to quantify the costs of uncomplicated total hip arthroplasty in the public health environment.  Various studies referenced in this research, such as those by Meyer et al.⁴ and Rana & William et al.⁶, indicate that 66% of the costs of THA derived from the cost of the prosthesis, the anaesthesia and operating room costs, and the nursing and hospital costs;  Rana & Williams, however, concluded that the strongest predictor of cost in these procedures was the length of stay.⁶
 

1. Differentiate between the incidence of major or minor complications:
   1. A major complication was defined as "...deep wound infection, wound dehiscence, cerebral vascular accident, pulmonary embolism, failure to wean intubation, unplanned reintubation, cardiac arrest, myocardial infarction, sepsis, and unplanned reoperation. or minor." ^11(p2)
   2. A minor complication was defined as "…superficial wound infection, acute renal failure, deep venous thrombosis, peripheral neurological deficit, bleeding occurrence(s) requiring transfusion, and pneumonia." ^11(p2)

• COPD was the only comorbidity that increased the risk of readmission within 30 days.
• Congestive heart failure was the only comorbidity that increased the risk of significant complications following THA. These patients were also at an increased risk of postoperative mortality, which becomes an essential factor to consider preoperatively.
• Patients who were 85 years and older were at increased risk of minor complications and bleeding, which required transfusion than those in the 80-84 cohort.
• Male patients experienced less risk of minor complications or bleeding occurrence, which concurred with Dlamini et al.
• Operating times of longer than 120 minutes, and  an American Society of Anesthesiologists (ASA) score >2,  were both "..independently associated with increased risk of minor complications and bleeding occurrences." ^{11(pg 4)}
• Finally, of interest given the rising levels of obesity in our global societies, Yohe et al. found that overweight and obese patients  - those with BMI's of 25-25.9 and > 30 respectively - had reduced risks of bleeding occurrences requiring a transfusion compared to the normal BMI cohort. Based on this finding, the researchers stress that it is of utmost importance in this population group – the oldest of the old  -  to consider the presence of under-nutrition, which they say may be present in as many as 38% of elderly patients.

• Yohe et al. did not define the average length of postoperative stay for their sample group. However, the South African studies indicated that the mean average stay for patients with uncomplicated elective THA conducted within the public health system was significantly less than those recorded in studies reviewed from the US, UK and Pakistan. Dlamini et al. recorded a mean average of 5 days, and Sikettio and Aden a mean of 7.5 days.
• Both Dlamini et al. and Yohe et al. found that female patients were more likely to experience complications and extended length of stay for these elective procedures.
• The finding by Dlamini et al. of the correlation between pre-operative maximum walking distance capability and a successful outcome post-operatively, including the prevention of extended length-of-stay, should be considered when developing standardised pre-operative assessment protocols.
• Similarly, the link between nutrition and risk of bleeding tendency in the elderly cohort as established by Yohe et al. should be given particular attention in light of the economic demographic of our population and the high rate of malnutrition in our population.
• Finally, all three studies highlighted a high correlation between length of operative time and increased risk for bleeding, extended length-of-stay and readmission due to peri-operative and postoperative complications. Much of which could arguably be mitigated by adequate pre-assessment.

 
In conclusion, then, it appears in contrast to commonly held beliefs, there is an increasingly ageing population in South Africa, that, together with several distinct drivers such as the high incidence of HIV, trauma and another infectious disease, has resulted in an increased demand for total hip arthroplasty in our public healthcare system.

Setting aside questions of capacity and accessibility, the costs for conducting these THAs within the public health domain compare favourably with those in the private healthcare system. Nonetheless, such cost containment is prefaced on implementing standardised protocols, including robust pre-operative screening procedures and protocols aimed at reducing peri-and postoperative complications.

Finally, to determine and monitor the full scope of the healthcare burden from such procedures to inform such protocols, there is, as indicated by Paruk et al., a need for a national registry inclusive of both public and private sectors.

To this end, the South African Orthopaedic Association launched its 'world-first' combined orthopaedic registry in 2019. Visit the Association's website for more information - https://saoa.org.za/sa-orthopaedic-registry/  or watch their promotional video featured below.

 

Dlamini, NF, Ryan, PV, & Moodley, Y. (2019). Incidence and risk factors for extended postoperative length of stay following primary hip arthroplasty in a South African setting. SA Orthopaedic Journal

 Sekeitto, A R, & Aden, A A. (2021). Costing total hip arthroplasty in a South African state tertiary hospital. South African Medical Journal
Yohe, N., Weisberg, M. D., Ciminero, M., Mannino, A., Erez, O., & Saleh, A. (2020). Complications and Readmissions After Total Hip Replacement in Octogenarians and Nonagenarians. Geriatric Orthopaedic Surgery & Rehabilitation. 

Contributor: Linda Ravenhill
Linda Ravenhill is a medical professional with an MA in Journalism. She has worked in the medical, technology and digital development spaces for over 25 years, & has a particular interest in the impact of technology on the delivery of healthcare in the Sub-Saharan Africa region.