For patients with hip pain due to a variety of conditions, THA can relieve pain, can restore function, and can improve quality of life. Surgical technique, biomaterials, design of the prosthesis and fixation techniques have evolved with time adjusting to each other. Sir John Charnley, a British orthopaedic surgeon, developed the fundamental principles of the artificial hip and is credited as the father of THA. He designed a hip prosthesis in the mid to late 1960s that still sees use today. It is estimated that over 300,000 THAs are performed each year in the United States alone [1].

THA has revolutionized the quality of life of men and women of all ages since the 1960s, earning the title of “the operation of the century.” [2] In 2010, a survey of National Joint Registries (NJRs) estimated that around 959,000 annual primary and revision total hip procedures were being performed annually with the average rate at about 131 procedures per 100,000 population, and the average revision burden was found to be 12.9% [3]. Interestingly, 57.7% of the patients were women and 32.9% of patients were under the age of 65 years. On the financial side, the global market for a hip replacement has been estimated to be around $4.8 billion in 2014 with an estimated forecast of $5.9 billion by 2020 [4].

The clinical benefit and cost-effectiveness of the procedure are well proven. A systematic review of the cost-effectiveness has estimated the cost of a THA compared with no surgery at $10,402 per quality-adjusted life year gained. Furthermore, if the World Health Organizations' suggested cost-effectiveness threshold of <3 times the gross domestic product, or $144,000 based on 2011 data for the US, is used, then THA can be considered a highly cost-effective intervention [5].

The normal hip functions as a "ball-and-socket" joint. The femoral head (ball) articulates with the acetabulum (socket), allowing smooth range of motion in multiple planes. Any condition that affects either of these structures can lead to deterioration of the joint. This, in turn, can lead to deformity, pain, and loss of function. The most common condition affecting the hip in this way is osteoarthritis. Other conditions that may affect the hip adversely include inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis, spondyloarthropathies, etc), developmental dysplasia of hip, childhood hip disorders (Legg-Calve-Perthes disease, slipped capital femoral epiphysis, etc), trauma, neoplasms, and osteonecrosis of hip. THA is a procedure whereby the diseased articular surfaces are replaced with synthetic materials, thus relieving pain and improving joint kinematics and function [6].

THA is an elective procedure and should be considered as an option among other alternatives. The decision to proceed with THA is made with an understanding of the potential risks and benefits. A thorough understanding of both the procedure and the anticipated outcome is an important part of the decision-making process. For the appropriate candidate, THA can be a life-altering procedure that relieves pain, improves function, and enhances quality of life. Like any other operative procedures, THA does have its limitations and complications. Some of them are fatal, and some are minor, which may become manifested years after surgery. Each next surgical procedure following previous hip surgery is associated with considerably lower chances to be successful. Therefore, in primary total hip arthroplasty, preoperative evaluation and preparation of patients are essential. Absolute contraindication includes active infection of the hip joint, infection in any other region of the body and any medical condition that compromise patients ability to with stand anaesthesia, metabolic demands of surgery, wound healing and significant rehabilitation necessary to ensure a favourable functional outcome [7].

Relative contraindication includes any process rapidly destroying bone, neuropathic joint, insufficiency of abductor mechanism and urinary tract infection particularly with Klebsiella. Various complications with THR surgery include neurovascular injuries, fracture of femur and acetabulum, post-operative infection, limb length discrepancy, dislocation of hip joint, which are catastrophic. Femoral and acetabular loosening have emerged as the most serious long term complication.

Quality of life (QoL) assessment is becoming increasingly important for measuring the impact of illnesses, diseases, and their treatment and for deciding priorities when allocating resources. The World Health Organization (WHO) has defined “QOL” as “an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns” [8]. Recently, many general instruments have been used to measure QOL in different groups (e.g., patients, workers, population and so on). Disability has a substantial impact on the quality of life of patients and affects daily living [9]. It is associated with extensive direct and indirect costs and represents a considerable burden for the health care system and the society in general. The leading reason for locomotor disability in the general population is osteoarthritis (OA) [10].  Data from the Centers for Disease Control (CDC) show that approximately 1 in 3 adults (37.6%) with arthritis of hip reported limitation in their usual activities [11]. Depression, intensity of pain, level of education, BMI and social contacts are the most important factors associated with disability of the lower limb in patients suffering from osteoarthritis of the knee or hip.

Standard Harris Hip Score (HHS) is a validated and the most commonly used tool to measure the functional capacity of an individual before and after a surgical procedure. It has been used extensively in many studies for evaluating functional outcomes of THRs. However, HHS includes a component of physical examination, which can vary widely among examining surgeons Subsequently to minimise this variability, modified HHS was developed in which the clinical evaluation part was removed. Modified HHS has been used in the past to assess functional outcome of THR over telephone and for assessing functional outcome in non-traumatic indications of THR [12].

1. HCPUnet. Healthcare Cost and Utilization Project. Agency for Healthcare Research and Quality, www.hcupnet.ahrq.gov.

2. Learmonth, I.D. et al. “The operation of the century: Total hip replacement.” The Lancet, vol. 370, 2007, pp. 1508–1519.

3. Kurtz, S.M. et al. “International survey of primary and revision total hip replacement.” International Orthopaedics, vol. 35, 2011, pp. 1783–1789.

4. Markets and Markets. “Hip replacement market worth 5.9 billion USD by 2020.” Markets and Markets, www.marketsandmarkets.com/PressReleases/hip-reconstruction-devices.asp.

5. Daigle, M.E. et al. “The cost-effectiveness of total joint arthroplasty: A systematic review of published literature.” Best Practice & Research Clinical Rheumatology, vol. 26, 2012, pp. 649–658.

6. Sherrington, C. et al. “A randomized controlled trial of weight-bearing versus non-weight-bearing exercise for improving physical ability after usual care for hip fracture.” Archives of Physical Medicine and Rehabilitation, vol. 85, no. 5, 2004, pp. 710–716, https://doi.org/10.1016/S0003-9993(03)00620-8.

7. Dudics, S. et al. “Natural products for the treatment of autoimmune arthritis: their mechanisms of action, targeted delivery, and interplay with the host microbiome.” International Journal of Molecular Sciences, vol. 19, no. 9, 2018, https://doi.org/10.3390/IJMS19092508.

8. The WHOQOL Group. “What quality of life? world health organization quality of life assessment.” World Health Forum, vol. 17, no. 4, 1996, pp. 354–356.

9. Song, J. et al. “Population impact of arthritis on disability in older adults.” Arthritis & Rheumatism, vol. 55, no. 2, 2006, pp. 248–255.

10. Dominick, K.L. et al. “Health-related quality of life and health service use among older adults with osteoarthritis.” Arthritis & Rheumatism, vol. 51, no. 3, 2004, pp. 326–3114.

11. Centers for Disease Control and Prevention. “Racial/ethnic differences in the prevalence and impact of doctor-diagnosed arthritis—United States, 2002.” Morbidity and Mortality Weekly Report, vol. 54, 2005, pp. 119–123.

12. Poolman, R.W. et al. “Outcome instruments: Rationale for their use.” The Journal of Bone and Joint Surgery. American Volume, vol. 91, suppl. 3, May 2009, pp. 41–49, https://doi.org/10.2106/JBJS.H.01551.