The joint reconstruction market covers large joints, such as the hip, knees and shoulders, and small joints, such as wrists, digits, ankles and elbows. Joint reconstruction devices such as hip and knee implants are placed inside the body to replace worn out joints and relieve the excruciating pain they cause. Age and trauma have been attributed as the leading causes of worn out joints.

The market was valued at $13.7bn in 2009 and is forecast to grow at a compound annual growth rate (CAGR) of 8% during 2009-2016. The market is expected to grow due to ageing populations across the world and the growing incidence of osteoarthritis.

Technological advances in implant materials and design, as well as the development of new procedures, are also enabling young arthritis patients to undergo joint reconstruction procedures. Direct-to-consumer campaigns by leading implant manufacturers have also drastically improved patient awareness about treatment options, shifting the mindset of patients who no longer want to bear the discomfort of pain. The result is more patients opting for surgery in order to lead a more active lifestyle.

Looking back and forward

Valued at $6.8bn, the knee replacement market was the biggest segment of the joint reconstruction market in 2009, and grew at a 9% CAGR from 2002-2009. The hip replacement market was the second largest market at $5.7bn and grew at a 7% CAGR from 2002-2009, while the shoulder replacement market was valued at $578.9m and grew at a 10% CAGR. Hip resurfacing was valued at $357.1m and was the fastest-growing joint reconstruction segment during the period, with an 18% CAGR.

The global joint reconstruction market is forecast to grow to $23.8bn by 2016. The knee replacement market will remain the biggest segment at $13.1bn in 2016, growing at a 10% CAGR. The hip replacement market is forecast to grow to $8.7bn in 2016, growing at a 6% CAGR, while the shoulder replacement market will grow at a 9% CAGR and is expected to exceed $1bn by 2016.The hip resurfacing market is forecast to reach $561m, growing at a 7% CAGR over the forecast period.

New procedures

“Procedures such as hip resurfacing and partial knee replacement, which use minimally invasive surgery techniques, are gaining popularity since they conserve the undamaged portion of the bone.”

Procedures such as hip resurfacing and partial knee replacement, which use minimally invasive surgery techniques, are gaining popularity since they conserve the undamaged portion of the bone, have shown good medium-term outcomes and are conducive to quick recovery and rehabilitation, as well as inflicting less pain.

Minimally invasive procedures use smaller incisions, measuring 4-6in as opposed to the 8-10in of traditional surgery. The patient benefits from reduced blood loss and tissue injury, allowing for a potentially faster recovery. This type of surgery also reduces the risk of wound infections, one of the major complications with total joint replacement surgery.

These procedures are targeted at adults aged 45-65 since they are more likely to benefit from gaining the bridge period between partial replacement and primary joint replacement. Partial or unicompartmental knee replacement involves the replacement of only the damaged component (either the medial or lateral compartment) of the knee. The implants used in the surgery are known as unicondylar knee replacement systems, the most popular of which employ metal-on-polymer designs.

Reverse shoulder surgery, another new type of procedure, provides older patients with end-stage rotator cuff tear with the option of surgery. It involves the reversal of the anatomy of a healthy shoulder: the femoral head is converted into the socket, while the ball portion of the implant is attached to the scapula. The surgery provides higher joint stability and a greater degree of joint movement.

Implant design technology

Advancements in implant technology have led to enhanced durability and function, with new implants claiming to last up to 20-25 years, compared with 15 years at present.

Due to the limited lifespan of the artificial joints, people under the age of 40 are generally not recommended surgery since they will outlive the implant, and revision surgeries to replace worn-out implants are difficult procedures. With superior implant materials increasing durability, an increasing number of young patients are now choosing surgery.

“Advancements in implant technology have led to enhanced durability and function, with new implants claiming to last up to 20-25 years, compared with 15 years at present.”

Advanced designs have led to the development of high joint stability and functionality, which provide a much better degree of movement. For instance, high-flex knees provide flexibility of up to 155 degrees, compared to the 125 degrees offered by conventional implants, while mobile-bearing knees allow the joint to rotate as well as glide, thus providing a more natural range of movement. These technological improvements have made surgery a more viable option for young, active patients.

Alternative bearing surfaces such as ultra-high molecular weight polyethylene (UHMWPE) or highly cross-linked polyethylene result in a low amount of friction when rubbing against a highly polished metallic surface, leading to the emergence of metal-on-polymer implants. For instance, Smith & Nephew’s Verilast technology uses UHMWPE as one of the bearing surfaces along with a transformed metal alloy. Meanwhile, advancements in polymer technology have resulted in the introduction of implantable grade polyether ether ketone, which has shown promising results due to its versatility and mechanical strength.

Ceramic-on-polyethylene combinations are also being considered as alternative bearing surfaces, as technology has resolved brittleness issues. New ceramic materials such as oxidised zirconium or oxinium, a transformed metal alloy, have resulted in the emergence of high-performance ceramic knee implants. The material has a ceramic bearing surface that combines low-friction and wear-resistant technology with the strength of a metal implant.

A new range of porous biomaterials has resulted in the development of cementless joint implants, which are claimed to be sturdier and longer lasting due to bone in-growth. Since cementless joint implants are better suited to young recipients, these materials have increased in importance.

Almost all the top players have proprietary in-growth promoting foam metals that are used in their products. The porous nature of the material is similar to bone and enables the new tissue to grow into the porous surface of the implant, providing added strength.

Computer-aided surgery

Computer-aided surgery (CAS) is now being adopted across the globe in a major way due to superior surgery outcomes, with a much smaller percentage of patients requiring revision surgery.

A five-year study of 1,000 procedures with computer-assisted robotic total knee replacements at Mercy Medical Center in New York, US, demonstrated that computer-assisted procedures resulted in better leg alignment, less likelihood of complicating infections, and a lower early failure rate than surgeries performed using conventional techniques.

The key indications for CAS are knee and hip replacements, a significant percentage of which are traditionally subject to a revision outcome within five or ten years.

“Computer-aided surgery is being adopted across the globe in a major way due to superior surgery outcomes.”

This is due to variations in surgical techniques, which included incorrect positioning or orientation of implants and improper alignment of the limb, leading to sub-optimal outcomes. CAS uses computer navigation technology, which results in enhanced accuracy during the fixation of implants.

The technique promises to provide improved functionality, better fits, improved quality of life and reduced post-operative pain. Companies such as Smith & Nephew have developed CAS technology, specifically for hip and knee replacement surgery. Its AchieveCAS system is a surgical tool that provides real-time navigation information.

Rising osteoarthritis

The global elderly population is rapidly growing due to a rise in average life expectancy, sparking a growth in the incidence of degenerative conditions such as osteoarthritis.

According to the World Health Organization, osteoarthritis accounts for more than 50% of the musculoskeletal disease burden. It is expected to be felt the most in developing countries, where life expectancy is increasing and access to arthroplasty and joint replacement is not readily available.

Rising obesity levels among the middle-aged is also expected to contribute to the earlier onset of osteoarthritis. Worldwide, there are 400 million adults defined as obese. Obesity levels range from below 5% in China, Japan and certain African nations to more than 75% in urban Samoa. By 2030, the number of obese adults is projected to grow to 573 million worldwide.

Despite rising numbers of people suffering from hip and knee joint disorders because of the factors outlined above, the need to remain active in later life is increasing steadily, and more old people now demand a better quality of life compared with earlier generations.

“Disease-modifying anti-rheumatic drugs are able to slow the progression of osteoarthritis to some extent, but drugs that stop progression are still decades away.”

It is estimated that more adults above the age of 65 years will need to continue to work to sustain themselves financially, and surgery is the only option through which they can regain substantial mobility and stay free of pain. These trends are expected to drive joint replacement surgery volumes in the future.

Medical solutions for end-stage or severe osteoarthritis are limited in scope and only help in symptom management, so surgery is the only option for treatment. The first line of medical therapy for mild-to-moderate osteoarthritis comprises pain medications and anti–inflammatory drugs, which are palliative and do not stop disease progression. In severe cases, pain medications are virtually ineffective. Disease-modifying anti- rheumatic drugs are able to slow the progression of the disease to some extent, but drugs that stop progression are still decades away.

Moreover, controversies over the safety of pain relief medications such as the Cycloxygenase-2 inhibitors are leading some to prefer non-pharmacological options for long-term pain relief. Thus, given the inevitability of losing joint function at some point, people with moderate-to-severe osteoarthritis are increasingly opting for joint replacement surgery.

Product recalls

Over the past few months, several reports about high failure rate of the DePuy ASR metal-on-metal hip replacement have surfaced. In the US, the Food and Drug Administration has received about 300 complaints relating to DePuy ASR hip problems since the beginning of 2008, while in the UK, the Medicines and Healthcare products Regulatory Agency (MHRA) has started reviewing potential problems with metal-on-metal hip implants. There are also growing concerns that the implants may cause non-cancerous tumours, swelling and other hip damage.

The MHRA has issued a guideline to doctors that requires patients fitted with metal-on-metal hip implants to be given regular follow-ups. These patients will have annual follow-ups for at least five years post-operatively, and more frequently in the presence of symptoms.

Considering that there is an increasing emphasis on reducing costs, these additional checks will put a burden on hospitals and surgeons. It is estimated that most surgeons will therefore switch to other hip replacement options, resulting in a significant loss in revenue for companies selling metal-on-metal hip replacement products, such as DePuy and Biomet.

“The top three companies, Zimmer, DePuy and Stryker, accounted for 60% of the total joint reconstruction market in 2009.”

In the pipeline

The top three companies, Zimmer, DePuy and Stryker, accounted for 60% of the total joint reconstruction market in 2009, with Zimmer and DePuy each holding a share of approximately 21%. Other significant players in the market are Smith & Nephew, Biomet and Wright Medical Technologies. Zimmer’s differentiating products are responsible for the company’s leading position in the knee replacement market.

Hip and knee-replacement products make up 70% of those in the pipeline. Most first-in-class pipeline products for these segments focus on increasing durability, bone conservation and enhanced mobility using innovative implant design.

For instance, iTotal is a tricompartmental knee resurfacing device intended for use in treatment of end-stage osteoarthritis. It uses scanned data to resurface the end of the thigh bone, providing an anatomic fit with far less bone cutting. Products such as the Signature personalised patient care system (Biomet) and the HemiCAP Femoral Condyle (Arthrosurface) showcase the next-generation of knee implants, where the implant is ordered specifically according to the patient’s knee anatomy.

There are many hip replacement pipeline products, which are experimenting with alternative bearing surfaces such as ceramic-on-ceramic and ceramic-on-polyethylene materials. A number of shoulder replacement pipeline products are experimenting with new implant materials.