Osteoarthritis and joint replacement surgery

Causes and future treatments
The management of the disease is broadly divided into non-pharmacological, pharmacological and surgical treatments. There are a number of drugs under development and there are several drugs on the market whose clinical effectiveness and long-term safety still need to be determined.
 
Scientists believe they are close to discovering the cause of osteoarthritis, offering the hope of more effective treatment. A team from the University of Southern Denmark found that shortened ends of chromosomes are linked to the onset of osteoarthritis.
 
Abnormally short chromosome caps, called telomeres, were found in cells from damaged knee joints and those near the areas of severe damage were "ultra short".  Researchers suggest that these lengths of DNA play an important role in the development of the osteoarthritis and it is hoped that this finding will lead to a more effective treatment for the disease. 
 
In 2012 The Lancet reported, "An important first step", which could also lead to new treatments for the disease. Researchers from Newcastle University, UK, discovered eight sections of our DNA that are responsible for osteoarthritis. They suggest that, at least two or three of these genetic regions could be used to treat the condition since they all contain genes responsible for the production of cartilage: the tissue between bones that is damaged by osteoarthritis.
 
A 2013 article in Cell Death and Disease found that urocortin, a naturally occurring protein is crucial for the survival of chrondrocyte cells that produce and maintain healthy cartilage. According to Professor Paul Townsend from the University of Manchester and co-lead researcher of the study, "boosting the level of urocortin could be a huge breakthrough since it would help to provide long-term benefit for osteoarthritis and also act as a preventative agent".  
 
Researchers acknowledge it will be some time before an effective treatment is developed and in the meantime, the incidence of joint replacement surgeries are expected to increase, particularly among younger patients.
 
Knee replacement surgery evolving
While all joints are affected by osteoarthritis, knee replacement surgery is fast becoming a treatment of choice when there is severe joint pain or dysfunction, which is not alleviated by less-invasive therapies.
 
The treatment modality is rapidly evolving and benefits from ongoing advances in surgical techniques, medical technology and prosthesis design. Combined with the use of minimally invasive surgery, gender-specific prosthetics and computer-assisted navigation systems; orthopaedic surgeons are now able to offer patients total and partial knee replacement procedures that are associated with minimal risks, smaller incisions, faster and less painful rehabilitation, reduced hospital stays and durable, well-aligned, highly functional knees.
 
Today, 95% of all knee replacement procedures can be confidently predicted to be successful and, even 10 to 15 years after the operation, will still be giving good service. However, given that more people are electing to have joint replacement surgeries at increasingly younger ages; 10 to 15 years might not be long enough.

Baby boomers electing to replace their warn-out knees
According to a 2012 US study published in the Journal of the American Medical Association, between 1991 and 2010, the incidence of knee replacement surgery increased by 161.5% for Medicare recipients alone. Today, in the US, knee replacement surgery is one of the most common surgeries being performed and costs between US$11,000 and US$50,000 per knee.
 
During the nine year study period, 3.2 million Medicare beneficiaries underwent knee replacement surgery, which at the lowest end of the cost spectrum, amounts to about US$3.2 billion for new knees for Medicare patients.
 
Many active middle-agers are wearing out their joints with running and sport and suffering osteoarthritis years earlier than previous generations. In the US, baby boomers are turning 65 at the rate of 8,000 a day and a significant number of these are opting for joint replacement surgery earlier in life rather than long term medical therapies.
 
According to the American Academy of Orthopaedic Surgery the fastest-growing patient group opting for joint replacement surgery is between 46 and 64. By 2016, over 50% of all US knee-replacement surgeries are expected to be performed on people under 65.
 
Projections suggest, in 10 years time, over three million knee replacements will be undertaken each year in the US alone and the demand for new knees could outpace there availability.
 
The future is replacement revisions
Arthritis Research UK is investigating the success rates of knee replacement surgery in younger age groups.  According to its medical director, Professor Alan Silman, in 2010 there were some 90,000 knee replacement operations performed in the UK and increasingly these are being carried out on people under 50.
 
Today, younger patients are more informed about surgical procedures and are more likely than past generations to demand specific treatments. "Patients with osteoarthritic knees", says Professor Silman, "demand earlier surgical intervention."
 
According to the UK's Office of National Statistics, a third of babies born in 2012 will live to 100. Longevity is one of the successes of 20^th century medical science and today, millions are retiring with a third of their lives still ahead of them.
 
No one knows the longevity of knee replacements in younger patients. According to Professor Silman, "We may well be faced with doing a lot more replacement revisions when these patients reach their 70s".