Knee surgery is one of the most common surgery but that does not mean routine surgery. Find out how recently techniques have evolved and what robotics and stem cells therapy might change.
Combined with the use of minimally invasive surgery (MIS) techniques, gender specific prosthetics and computer-assisted navigation systems, orthopedic surgeons are now able to offer patients knee replacement procedures that are associated with
minimal risks during and after surgery by avoiding fat embolism, reducing blood loss and minimising soft tissue disruption;
faster and less painful rehabilitation;
reduced hospital stay and faster return to normal activities of daily living;
an improved range of motion;
less requirement for analgesics; and
a durable, well-aligned, highly functional knee.
With the ongoing advancements in surgical technique, medical technology and prosthesis design, knee replacement surgery is constantly evolving.
What are the Surgical Options for Knee Arthritis?
The Classical Arthroscopy
Arthroscopy involves a surgeon making a small incision in your knee and irrigating and removing loose pieces of cartilage. In the arthritic knee, there is a very limited role for an arthroscopy. Results of a “clean out” or a “wash out” are unpredictable at best and should be avoided.
Partial Knee Replacement – The Unicompartmental Knee
A surgeon performing a partial knee replacement, also known as a “uni,” replaces only the part of the knee that is worn out. This can be either the knee cap-femur joint (patello-femoral) or more commonly – the femur-shin joint (femoral-tibial). These procedures are appealing because they are generally less invasive, more normal tissue is retained, and recovery is easier.
The ideal candidate for these procedures is an evolving topic. Issues of location and amount of disease as well as the amount of deformity present are important considerations. Newer technologies such as computers, robots and custom guides have been introduced to this concept in attempts to improve outcomes. The influence of these technologies has yet to be determined. Outcomes of partial knee replacements can be comparable to total knee replacements ten years after surgery.
Total Knee Replacement
Total Knee Replacement (TKR) is the gold standard when conservative treatment for arthritis of your knee has failed. This procedure involves resecting the ends of the bones of the knee and replacing them with a combination of metal and plastic. The procedure is one of the most successful of all surgical procedures. On average, TKR provides 90-95% pain relief and has a 1-2% complication rate. Approximately 90% of replaced knees will be satisfactory twenty years after surgery. Read more about knee replacement procedure.
What is an Osteotomy?
This procedure involves cutting the bone and reorienting the alignment of the knee. It has traditionally been reserved for younger patients with malaligned knees who participate in high-demand activities such as sports. Osteotomy has fallen out of favor due to inferior results compared to knee replacements. There are some newer technologies that may improve outcomes, but currently osteotomy has a limited role in the treatment of osteoarthritis of the knee.
The new Cartilage Procedure Involving Cells Therapy
This procedure, according to AAHKS, involves harvesting cartilage cells and transplanting them into the area of disease in your knee. While appealing in concept, there is very little role for this procedure in an arthritic knee and has no role to play in the treatment of the advanced arthritic knee.
What are the Knee Surgery New Procedures?
If only your kneecap is damaged, an operation called a patellofemoral replacement or patellofemoral joint arthroplasty can be performed. This involves a smaller surgery with a faster recovery time. However, the long-term results are still unclear and it's not suitable for most people with osteoarthritis.
The Recent Knee Image-guided Surgery
The surgeon performs this operation using computerised images, which are generated by attaching infrared beacons to parts of your leg and to the operating tools. These are tracked on infrared cameras in the operating theatre. Results so far suggest that this may enable the new knee joint to be positioned more accurately.
Most hospitals don't yet have the equipment to do this and only around 1% of knee replacements are performed in this way.
Knee Replacements for Women - There are differences in size and movement between women's and men's knees. This may be linked to a greater incidence of knee osteoarthritis in women compared to men as they age. New replacement parts and advances in techniques allow physicians to more precisely match replacement knee components to the patient, a method referred to as gender-specific implant.
Recent Advances in Knee Replacement Surgery
Minimally invasive surgery (MIS) has revolutionized knee replacement surgery as well as many fields of medicine. Its key characteristic is that it uses specialized techniques and instruments to enable the surgeon to perform major surgery without a large incision.
Minimally invasive knee joint replacement requires a much smaller incision, 3 to 5 inches, versus the standard approach and incision. The smaller, less invasive approaches result in less tissue damage by allowing the surgeon to work between the fibers of the quadriceps muscles instead of requiring an incision through the tendon. It may lead to less pain, decreased recovery time and better motion due to less scar tissue formation.
Currently this less invasive procedure is performed by only a small percentage of orthopedic surgeons in North America.
This new technique has been recommended by the National Institute for Health and Care Excellence (NICE). It can be used for either total or half knee replacements, but is currently more commonly used for half knee replacements.
More recently, several new technologies had been introduced by the end of 2018 according to Doctors Iont and Proit.
Patient-specific Cutting Blocks
With this technology, the patient receives either a CT scan or an MRI. The scan is then sent to the manufacturing company. Technicians measure certain anatomical features of the patient's knee. A computerized surgical plan is sent to the surgeon. This plan contains detailed information as to the appropriate size implants and location of the bone cuts. After approval by the surgeon, the manufacturer creates specialized cutting blocks for that particular patient. These cutting blocks allow for bone cuts to be made with the patient's specific anatomy in mind to allow for optimal fit and alignment. This in turn, theoretically, may lead to longer implant life, more range of motion, and a quicker operation. However, "off-the-shelf" implants are still utilized.
A similar process is utilized with either a CT scan or MRI. In this case, not only are cutting blocks manufactured to fit the patient's own anatomy but also the knee replacement implants. This is the cutting edge of patient-specific knee replacement. However, this technology is not yet widely available.
These are truly exciting new advances in the field of knee replacement surgery. The drawbacks of this technology are the costs involved. Both incorporate the use of advanced imaging studies. Not only are these expensive, but in the case of a CT scan, it exposes the patient to significant amounts of radiation. Additionally, because the technologies are new, there is no long-term proof that these offer improved function or longevity according to Healthfitnessmag. With recent changes in health care delivery and a growing focus on cost containment, these technologies may never become widely available.
Advancement in Artifical Joint Replacement
The concept of biological joint reconstruction envisions the replacement of the degenerative articular cartilage with biologic, non-artificial, material that can be fully incorporated and integrated with the remaining healthy tissue. Even though the idea is miraculous, unfortunately the regeneration of articular cartilage has proven not a simple task so far. Articular cartilage represents a tissue composed of thick collagenous extraarticular matrix maintained by chondrocytes, the only cellular component of articular cartilage. As such, articular cartilage lacks vessels and nerves, and it has a poor healing and regeneration potential. Therefore, any attempt to enhance this potential is condemned to fail, especially in an environment that led to degeneration in the first place.
During the evolution and further development of the biological approaches for joint reconstruction over the last years, there are some interesting advancements and that may be proven important milestones in further progressing the field.
Kinematically aligned total knee replacement - Starting approximately 10 years ago, kinematically aligned knee replacement surprised most of us with the favorable subjective outcome scores reported. The goal in kinematically aligned total knee replacement is to align the femoral and tibial components so that the three axes that describe tibiofemoral and patellofemoral kinematics would be restored according to the normal joint lines.
Navigation Assisted Arthroplasty
Navigation-assisted arthroplasty was an innovation that improves better alignment and positioning of the arthroplasty implant. Specifically, in a prospective study, it was shown that computer-assisted TKA was associated with significantly less variability, resulting in a mechanical axis with more than 3 degrees difference only in 4% of the cases, which was significantly lower to the 22% of the conventional technique.
Robotic technology in orthopedics
Robotic surgery is probably the application that can better depict the future involvement of technology in clinical orthopedic practice. Even though robotic-assisted surgery started its first steps more than 20 years ago, with orthopedics being one of the first specialties that used a robotic system, it was only at the last 5 years that its use has been remarkably extended. The experience reported so far with noncompartmental knee arthroplasty has shown that robotic systems can improve coronal alignment and show some improvement in clinical outcome compared to conventional noncompartmental knee arthroplasty. Several other reports suggest better alignment and accuracy with robotic assisted surgeries.
Advancement in Biological Joint Reconstruction
Primary and Stem Cell-based Therapies
Primary chondrocytes remain the golden standard as a cell source for treatment of cartilage lesions, 20 years after their description of autologous chondrocyte implantation (ACI) that has initiated the concept of biological joint repair. Despite the fact that ACI and subsequent modifications have been applied in clinical practice for several years, it was only recently that its superiority over microfracture was evident in metaanalyses.
The recruitment of endogenous cells in an anatomic compartment due to various stimuli, and their contribution in tissue healing and regeneration is defined as cell homing mechanism. Even though the initial hypothesis has been stated for tissue growth and development, it seems that cell homing is a mechanism that takes place in multiple levels and various physiological processes. This concept was proven valid in musculoskeletal tissue regeneration as well. The entire articular surface of the proximal humerus was successfully regenerated via cell homing only, without any cell transplantation in the joint.
Biologic Growth Factors
The extensive use of biologic factors that can enhance cartilage repair, or even prevent degeneration, is probably the most “hot topic” of the last decade. PRP (platelet rich plasma) is one of these modalities that has sworn enemies and sworn supporters. Despite their popularity, high quality evidence that justifies their use and supports its effectiveness was only recently released. Unfortunately the existing evidence seems contradictory and does not clearly favor PRP use.
Tissue Engineering, Regenerative Medicine Applications and Clinical Biological Approaches
The idea of creating tissues in vitro that they can be implanted to replace degenerative tissue is a fascinating approach. The field is advancing fast with significant improvement in the biomechanical properties of the engineered tissue. Two of the most appealing clinical applications that demonstrate promising data are the use of particulated juvenile articular cartilage and the use of NeoCart™, an autologous cartilage tissue implant. Both emerging techniques seem to have a favorable safety profile and they show improved clinical outcome.
In conclusion, biological joint reconstruction can serve as a transitional period prior to joint replacement in the near future. The combination of both techniques and their proper use according to their specific indications and known limitations seem to be the only viable solution for now, as well as for the future. The successful use of biological reconstruction will delay further the conventional primary joint replacement and may eliminate the need of revision surgery. As always, further research and more high level evidence are essential in order to clarify further the advantages and disadvantages of the emerging techniques and to promote validation of their effectiveness and safety.
Oxinium Knee Implant
Oxinium, Oxidized Zirconium is a metal alloy consisting of 97.5% zirconium and 2.5% niobium, two of the most biocompatible metals known to man. Oxinium is a superior implant that is expected to last longer and will allow active, younger patients to benefit much earlier from a replacement knee. With this material’s resistance to abrasion and anticipated longevity, patients can once again enjoy an active lifestyle for nearly thirty years with oxinium implants when compared to the regularly used Cobalt chromium implant. Significant advantages include the durability, improved wear resistance and biocompatibility especially for patients who have metal allergies and is expensive compared to the other implants.
Cementless fixation relies on new bone growing into the surface of the implant for fixation according to Doctor Prashanth. Cementless implants are made of a material that attracts new bone growth. Most are textured or coated so that the new bone actually grows into the surface of the implant and is expensive.
Last update 15th of October 2018