Total Joint Replacement: Metal, Plastic and Ceramic Hips and Knees?

Total joint replacements are performed for severe degenerative disease of the hip, knee, ankle, shoulder and even wrist, fingers and spinal segments. The two most common procedures are total hip and knee replacements and this it where we’ll start today.

Each year, over 62,000 hip and knee joint replacement surgeries are performed across Canada. The number of these surgeries performed actually doubled over the ten year period prior to 2007 as governments and hospital systems recognized the health and wellness benefits of providing patients with the ability to keep moving into their elder years. With the “move it or lose” philosophy finally encouraged by funding bodies, programs to shorten wait times and increase access to total hip and knee replacement surgeries were launched Canada wide.knee_gsf_nexgen_glass2_200px

Hip and knee joint replacement requires removal of the degenerative joint surfaces and resurfacing with a prosthetic implant or implants. For knees, the ends of the femur (thigh) bone and the tibia (leg) bone are shaved or cut and replaced with a metal component that articulates against a space age plastic insert. The components may be cemented in place in most cases or made of a porous material that allows bone to grow into the pores to bond metal to bone over time. Although the plastic is extremely durable, it may wear away over years and require revision with a new insert. The metal components may loosen over the years and also require revision. Total knee replacements can last up to 20 or more years in many patients.

hip_mltaper_kinectiv_continuum_glass_200Hip replacements require arthroplasty of the ball and socket joint which connects the thigh (femur) bone to the pelvic cup (acetabulum). We typically remove the ball, or head of the femur bone, and replace it with a metal or ceramic ball that inserts into the marrow canal of the femur with a metal stem. The acetabulum, or socket part of the joint, is resurfaced with a metal shell typically and a plastic, ceramic or metal liner that articulates with the ball portion of the implant. Some hip replacements will last over 30 years in patients. Revision takes place for loosening, wear of the liner, instability or failure of the integrity of the prosthetic components or the bone around the components. Total hips and knees can also fail for other reasons including infection.

A patient undergoing hip or knee replacement will stay in the hospital anywhere between 2 and 5 days and start physical therapy and rehabilitation while there. Pain management and the prevention of blood clots in the legs are two of the most important post operative issues that the medical team will address. Medications are given for pain either by intravenous injections or by mouth. The use of pain patches, epidural anesthesia or spinal anesthesia has improved post operative pain management for total joint patients. Patient controlled pain pumps are also commonly used in most hospitals.surgery

The field of joint replacement is huge with billions of dollars worldwide directed at research and development of more durable, longer-lasting and better functioning prosthesis. Alternate bearing surfaces such as ceramics, and highly cross linked plastics with antioxidants to prevent degradation are currently the hottest topics in joint replacement research.

The Canadian Joint Replacement Registry (CJRR) was launched in 2000 to create a database of patients and implants used for arthroplasty procedures in order to offer insights into successes, failures, trends and complications that surgeons and patients experience. We can also see some interesting statistics about who is undergoing these procedures, in what regions, and by whom.

For example, the CJRR tells us that compared to men, Canadian females have higher age-adjusted rates per 105 for both total knee replacements and total hip replacements. Accordingly, women account for 57% of patients receiving total hips and 61% of patients receiving total knees. Using CJRR data, a strong relationship between obesity and subsequent risk of undergoing both hip and knee replacements was found.  The largest increases in both total hip and knee surgery rates occurred in the 45–65-year age groups, where the greatest increases in Canadian obesity rates have also occurred.

The CJRR also highlights some of the differences in hip and knee replacement surgeries across the globe. In Sweden, the incidence of total knee replacements in females for 2006–2007 was 136 per 105, and in Canada it was 182 per 105. Although the reasons for these differences may have many factors, it is likely that the higher rates of total knee replacement in Canada may be related to a higher levels\ of obesity among Canadians.

By adding revision surgery information to the database, we should eventually be able to develop survivorship information for specific implant types, the addition of antibiotic to cement, to surgical approach, and many others factors that are involved in procedure, implant selection and post operative care.

For more information about the CJRR please visit the website.

And for more information about total joint replacements, please visit one of zimmerthe largest manufacturers of prosthetic joint products, Zimmer.

Disclosure: the author has not received any remuneration for this blog from Zimmer. Zimmer is currently the author’s affiliate hospital’s primary hip and knee arthroplasty vendor.

Knee Injuries in the Weekend Warrior

I promised to talk a bit about some of the more common knee injuries as part of the series on weekend warriors. I’d say that half of my practice deals with treating knees. Half again of those are arthritic knees who eventually need knee replacements (arthroplasty). That leaves 25% of my practice focused on the patient with knee trauma.

The Knee is More Than a Hinge

The Knee is a rather simple joint when compared to other joints, like the elbow for example, but it is not a simple hinge joint as you might expect. It bends, but also rolls back. It pivots, and it opens laterally and medially a bit as well.

The structures that allow these movements are called ligaments, and to some extent, the cartilage cushioned called menisci (or meniscus for one–we have two in each knee). The ligaments on the sides of the knee are the collaterals (medial and lateral) and in the middle of the knee are the cruciates (anterior and posterior).

knee anatomyThe joint surfaces, on the ends of the femur and tibia bones which make up the weight bearing parts of the knee are coated with hyaline cartilage like on the end of a chicken bone. These surfaces, coated by a slippery substance called synovial fluid, create the articulation where the actions occur–similar to the contact between a ball-bearing in an engine, or a piston, coated with oil.

Internal Derangements of the Knee

Any of these structures can be damaged or injured during a twist, fall, contusion or a pull. If the bone on either side of the joint don’t break, then the ligaments, menisci and even some of the tendons from the large leg and thigh muscles which pass by the knee can tear.

Knee-anatomy-570I typically see meniscal tears and ligament injuries. Occasionally we see fractures of the top of the tibia, knee cap (patellar) or end of the femur either alone or less commonly associated with the soft tissue injuries.

Meniscal Tears

A meniscal tear usually results from a twisting injury or some type of force to the knee outside of the normal anatomic mechanical motions that happen when we walk, run, climb, kneel, crawl or jump. Forces which result in injuries may be minor–the perfect twist–or major as in a soccer collision, a motor vehicle accident or a major fall from height.

Meniscal injuries can be left alone in young people if they occur in an area of good supply–and that’s really limited to the back of the medial meniscus. Unfortunately most meniscal injuries, even in young patients, do not heal and may go on to create early-onset degenerative osteoarthritis in the knee if they act as an irritant to the hyaline cartilage surfaces, particularly in the area of the tear. They may require repair (if in an area of good blood supply) or excision, where we trim out the torn area using a minimally invasive procedure called arthroscopy.Anterior-Cruciate-Ligament-ACL-Injury

Ligament Injuries

Some ligament injuries require surgery, some are better left alone to heal. A medial collateral ligament–the ligament on the medial or inner side of the knee–will typically heal if braced to avoid stress. An anterior cruciate ligament injury–if completely ruptured and causing instability of the knee–usually needs to be reconstructed. Lateral collateral ligaments and posterior cruciate ligaments may or may not need repair/reconstruction and generally depend on the patient’s lifestyle, age, and the surgeon’s experience and clinical examination.

I probably reconstruct at least 4 to 6 anterior cruciate ligaments each month–sometimes more, sometimes less. We use the small hamstrings of the thigh or the middle third of the tendon that attaches the knee cap (patella) to the leg (tibia) in order to create a new ligament. Bracing, cryotherapy, and a significant course of physical therapy are required to recover from this injury in most patients.

The Knee of the Weekend Warrior

A typical weekend warrior injury is a twist that results in pain, swelling, stiffness and decreased weight bearing tolerance. If this does not clear up with rest, ice, gentle ,movement and elevation of the leg after 2 or 3 dthCAZTK19Uays, then you should see your doctor for a physical examination. Xrays, ultrasound and clinical findings can diagnose most major knee issues that would require immediate attention. MRI’s are typically reserved for unresolving symptoms that do not get better over a few days or a short number of weeks in spite of a good effort at nonoperative therapies.

An MRI will help to better identify hidden fractures, ligament tears and meniscal tears.

To book a visit with Dr. Smith Auguste, please ask your family doctor to send a referral to fax: 416 352 5123.

The Right to Fight: The Dilemma of Boxing as a Sport for Youth

Thousands of boys and girls younger than 19 years 30of age participate in boxing in North America. Although boxing provides benefits for participants, including exercise, self-discipline and self-confidence, the sport of boxing encourages and rewards deliberate blows to the head and face. Because of the risk of head and facial injuries, the Canadian Paediatric Society and the American Academy of Pediatrics oppose boxing as a sport for children and adolescents. These organizations recommend that physicians vigorously oppose boxing in youth and encourage patients to participate in alternative sports in which intentional head blows are not central to the sport. (Source: http://www.cps.ca/en/documents/position/boxing)

On the other side of the controversy, the Turner Boxing Academy reports that the  National Safety Council ranked boxing 71st in sports injuries, well below mainstream sports like wrestling, football, baseball, soccer aglovesnd even bowling. Most of the negative publicity about the sport is centered around professional boxing, which in fact is much different than amateur boxing.

No other amateur sport takes more precautions in regards to safety than amateur boxing. Amateur boxers must receive a physical examination before and after each match and special protective equipment is mandathelmetory to enter the ring. The primary objective of all amateur referees is the safety of the boxers, and all competition gloves and headgear contain an exact combination of shock-absorbent foams to reduce impact..

According to Turner, amateur boxing is a sport that rewards technical proficiency and the use of athleticism rather than the power of administering pain. A point system is used to score each match, and knockdowns are worth one point, the same as a correctly positioned punch. The goal is to score points, not punches. Less than one percent of all amateur boxing contests end in a knockout, which is less than the overall infection rate for elective nonurgent surgeries.25

How does amateur boxing compare to safety stats for other sports? Turner reports that over 20% of all high school football players suffer at least one concussion per season with 10 – 15 deaths in high school football alone in North America. Baseball has the highest fatality rate among all sports for children aged 5 – 14.

Pathologist Ed Friedlander writes in his blog pathguy.com. that “whatever consensus documents my professional colleagues draft, there will always be many young males who want to engage in amateur boxing. In my opinion, the health risks of today’s amateur boxing, properly supervised, have been exaggerated badly enough to justify my speaking out in the sport’s defense.

Personally, after spending Sunday March 3rd, 2013 as ringside doc at the Right to Fight event in Barrie, I was amazed at the attention to detail, safety, sportsmanship and respect for the sport and heroes of the sport. Having never worked a boxing event prior to now, I too was somewhat skeptical concerning the support of boxing as a sport for youth where one of the goals is to hit the other player in the head.

Yet, having watched children plunge down icy steep slopes of Nakiska at full speed, having myself competed in windsurfing events in shark-infested waters, and considering the number of young athletes who chose to flip motocross bikes in the air off cement and wooden ramps, boxing as a sport seems somewhat tame and significantly more controlled on the safety side of competition than most of the sports I have officiated at or competed in. The sum total of my treatments Sunday: one bloody nose and one cut lip–no one needed stitches, no paramedics were called, and that is not the case at a typical ski race day in the Rockies. There will always be controversy. But in the end, the Right to Fight remains.

7

Raymond Olubowale, current Canadian Heavy Weight Champ.

12George Chuvalo, former Canadian Heavy Weight Champion and DOAC staff.

Sources:

http://www.pathguy.com/boxing.htm

http://www.cps.ca/en/documents/position/boxing

http://turnerboxingks.com/?page_id=103