New Quad Sparing Technique May Provide Faster Recovery for Patients with Arthritis of the Knee
Last updated: February 14, 2011
Broadly speaking there are two types ways to insert a total knee replacement: the traditional approach and the newer minimally-invasive (sometimes called quadriceps-sparing) approach.
Traditional total knee replacement involves a roughly 8” incision over the knee a hospital stay of 3-5 days and sometimes an additional stay in an inpatient rehabilitation setting before going home. The recovery period(during which the patient walks with a walker or cane) typically lasting from one to three months. The large majority of patients report substantial or complete relief of their arthritic symptoms once they have recovered from a total knee replacement.
Minimally-invasive quadriceps-sparing total knee replacement is a new surgical technique that allows surgeons to insert the same time-tested reliable knee replacement implants through a shorter incision using surgical approach that avoids trauma to the quadriceps muscle (see figure 1) which is the most important muscle group around the knee. This new technique which is sometimes called quadriceps-sparing knee replacement uses an incision that is typically only 3-4” in length (see figure 2) and the recovery time is much quicker – often permitting patients to walk with a cane within a couple of weeks of surgery or even earlier. The less-traumatic nature of the surgical approach also may decrease post-operative pain and diminish the need for rehab and therapy compared to more traditional approaches.
The main potential benefits of this new technique include:
The major apparent risks of the procedure compared to traditional total knee replacement:
For some patients an implant other than a total knee replacement may be a reasonable choice. Partial knee replacements sometimes called unicompartmental (partial) knee replacements (see figures 5 and 6) also have a long track record in this country and in Europe. Partial knee replacements have been around for decades and offer excellent clinical results just like total knee replacements. Less invasive techniques are available to insert these smaller implants as well but only a minority of knee replacement patients (about 10%) are good candidates for this procedure. Minimally-invasive partial knee replacement (mini knee) is the topic of another article on this website.
By contrast the minimally-invasive quadriceps-sparing total knee replacement is appropriate for most patterns of knee arthritis.
Symptoms & Diagnosis
Characteristics of knee arthritis
Swelling and warmth
However some patients have arthritis limited to one compartment of the knee--most commonly the medial side (see figure 11). When patients with one-compartment arthritis (also called “unicompartmental” arthritis) decide to get surgery they may be candidates for minimally-invasive partial knee replacement (mini knee) (see figure 12).
This broad category includes a wide variety of diagnoses including Rheumatoid arthritis lupus gout and many others. It is important that patients with these conditions be followed by a qualified rheumatologist as there are a number of exciting new treatments that may decrease the symptoms and perhaps even slow the progression of the joint damage.
Patients with inflammatory arthritis of the knee usually have joint damage in all three compartments and therefore are not good candidates for partial knee replacement. However inflammatory arthritis patients who decide to have total knee replacement have an extremely high likelihood of success; these patients often experience total or near-total pain relief following a well-performed joint replacement.
Osteoarthritis is also called OA or “degenerative joint disease.” OA patients represent the large majority of arthritis sufferers. OA may affect multiple joints or it may be localized to the involved knee. Activity limitations due to pain are the hallmarks of this disease.
OA patients who have symptoms limited to one compartment of the knee sometimes are good candidates for minimally-invasive partial knee replacement (mini knee).
Sometimes patients with knee pain don't have arthritis at all. Each knee has two rings of cartilage called "menisci" (this is the plural form of "meniscus"). The menisci work similarly to shock absorbers in a car.
Menisci may be torn acutely in a fall or as the result of other trauma or they may develop degenerative tears from wear-and-tear over many years. Patients with meniscus tears experience pain along the inside or outside of the knee; sometimes the pain is worse with deep squatting or twisting. Popping and locking of the knee are also occasional symptoms of meniscus tears.Since some of these symptoms may be present with arthritis and the treatment of arthritis is different from that of meniscus tears it is important to make the correct diagnosis. A good orthopedic surgeon can distinguish the two conditions by taking a thorough history performing a careful physical examination and by obtaining imaging tests. X-rays and Magnetic Resonance Imaging (MRI) scans may be helpful in distinguishing these two conditions.
Also called infectious arthritis or septic arthritis a joint infection is a severe problem that requires emergent medical (and often surgical) attention. If not treated promptly knee infections can cause rapid destruction of the joint; in the worst cases they can become life-threatening.
Symptoms of a knee joint infection include:
Patients who suffer from arthritis are not more likely to develop such infections. They may occur in anyone. Arthritis patients who develop such infections would notice a significant worsening in their pain as well as some of the other symptoms listed above.
A physician will make the diagnosis of a joint infection based on history and physical examination blood tests and by sampling joint fluid from the knee.
Again a joint infection is a serious condition that requires immediate medical attention.
Incidence and risk factorsKnee involvement by rheumatoid arthritis (RA) is common. Approximately 20-30% of patients with RA will have knees affected by this disease.
History and physical examination
An orthopedic surgeon will begin the evaluation with a thorough history and physical exam. Based on the results of these steps (s)he may order plain X-rays.
If a patient has arthritis of the knee it will be evident on routine X-rays of the joint. X-rays taken with the patient standing up are more helpful than those taken lying down as the way the knee joint functions under load (i.e. standing) provides important treatment clues to the physician.
Also plain X-rays will allow an orthopedic surgeon to determine whether the arthritis pattern would be suitable for total knee replacement or for a different operation such as minimally-invasive partial knee replacement (mini knee).
Although there is some level of inflammation present in all types of arthritis conditions that fall into the category of true inflammatory arthritis are often very well managed with a variety of medications and more treatments are coming out all the time. Individuals with rheumatoid arthritis and related conditions need to be evaluated and followed by a physician who specializes in those kinds of treatments called a rheumatologist. Excellent non-surgical treatments (including many new and effective drugs) are available for these patients; those treatments can delay (or avoid) the need for surgery and also help prevent the disease from affecting other joints.
So-called non-inflammatory conditions including osteoarthritis (sometimes called degenerative joint disease) also sometimes respond to oral medications (either painkillers like Tylenol or non-steroidal anti-inflammatory drugs like aspirin ibuprofen celebrex or vioxx) but in many cases symptoms persist despite that type of treatment.
It is important to avoid using narcotics (such as Tylenol #3 vicoden percocet or oxycodone) since they are have many side effects are habit-forming and make it harder to achieve pain-control safely and effectively after surgery should that become necessary. Narcotics are designed for people with short-term pain (like after a car accident or surgery) or for people with chronic pain who are not surgical candidates. People who feel they need narcotics to achieve pain control should consider seeing a joint replacement surgeon (an orthopedic surgeon with experience in knee replacements) to see whether surgery is a better option.
Nutritional supplements like glucosamine and chondroitin have been shown to decrease pain in many patients who use them. These products typically take 6-8 weeks to achieve their maximum effect. However they do not work for all patients who try them and despite what some advertisements suggest they do not appear to regrow cartilage or reverse the arthritic process.
Joint injections either with corticosteroids (“cortisone shots”) or with viscosupplements like Synvisc or Hyalgan may also provide temporary relief. These products do not work in all people who try them and there is some risk of infection associated with injecting the knee joint though this is not very likely.
However exercise and general physical fitness have numerous other health benefits. Regular range of motion exercises and weight bearing activity are important in maintaining muscle strength and overall aerobic (heart and lung) capacity and help prevent the development of osteoporosis which can complicate later treatment. Certainly people who are physically fit are more resilient and in general are more able to overcome the problems associated with arthritis. Physically fit people also tend to recover more quickly from surgery should that eventually be necessary to treat the knee arthritis.
Possible benefits of minimally-invasive (quadriceps-sparing) total knee replacement
The large majority (more than 90 percent) of total knee replacement patients experience substantial or complete relief of pain once they have recovered from the procedure. The large majority walk without a limp and most don’t require a cane even if they used one before the surgery. It is quite likely that you know someone with a knee replacement who walks so well that you don’t know (s)he even had surgery! Frequently the stiffness from arthritis also is relieved by the surgery. Very often the distance one can walk will improve as well because of diminished pain and stiffness. The enjoyment of reasonable recreational activities such as golf dancing traveling and swimming almost always improves following total knee replacement.
However there are some potential benefits of the newer less-invasive total knee technique over the traditional technique of total knee replacement.
The main potential benefits of this new technique include:
Joint replacement surgery is the most effective method for restoring comfort and function to knees damaged by severe arthritis. When the normally smooth surfaces of the knee joint are severely damaged by arthritis injury or surgery total knee replacement may be the most effective method for restoring comfort and function to the joint. For a minority of patients with arthritis a minimally-invasive partial knee replacement is an option instead of total knee replacement but most patients with knee arthritis who undergo surgery are better served with total knee replacement.
Other surgical options such as arthroscopy or “clean up” operations have not been shown to give lasting benefit.
Knee fusion can stabilize the joint and decrease pain but does not allow motion at the knee joint.
For selected younger and more active patients realigning the joint using a procedure called osteotomy may be appropriate; however the durability and pain relief of this procedure does not seem to measure up to joint replacement particularly in older patients.
Who should consider minimally-invasive (quadriceps-sparing) total knee replacement?
What happens without surgery?
Total knee replacement
There are now several ways to perform total knee arthroplasty:
Traditional Total Knee Replacement
But not every patient with knee arthritis needs (or should have) total knee replacement. There are many other surgical options available for patients with certain patterns of knee arthritis. These include:
Minimally-invasive partial knee replacement (unicompartmental knee)
Minimally-invasive partial knee replacement (mini knee) is not for everyone. Only certain patterns of knee arthritis are appropriately treated with this device through the smaller approach.
Generally speaking patients with inflammatory arthritis (like Rheumatoid arthritis or lupus) and patients with diffuse arthritis all throughout the knee should not receive partial knee replacements.
Patients who are considering knee replacements should ask their surgeon whether minimally-invasive partial knee replacement (mini knee) is right for them.
However if X-rays demonstrate a significant amount of arthritis this may not be a good choice. Knee arthroscopy for arthritis fails to relieve pain in about half of the patients who try it.
Osteotomy involves cutting and repositioning one of the bones around the knee joint. This is done to re-orient the loads that occur with normal walking and running so that these loads pass through a non-arthritic portion of the knee. That’s why it doesn’t work well if more than one compartment of the knee is involved--in those patients there is no “good” place through which the load can be redistributed.
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Many studies show that 90-95 percent of total knee replacements are still functioning well 10 years after the surgery. Most patients walk without a cane most can do stairs and arise from chairs normally and most resume their desired level of recreational activity.
The goal of minimally-invasive quadriceps-sparing total knee replacement is to capitalize on the decades of experience surgeons have gained in total knee implant design and intra-operative ligament balancing but provide patients with a faster recovery and less post-operative pain. The same knee replacement implants and materials are used the point of attachment to the bones is the same (bone cement) and the same attention to surgical detail limb alignment and ligament balancing are given during the newer less-invasive procedure as during the traditional approach. It is important to remember that this is a new procedure compared to traditional total knee replacement and as a result we do not have long-term follow-up on outcomes. However short term studies on knee component and limb alignment and peri-operative complications have found results with those endpoints that are comparable to traditional approaches while providing patients with faster rehabilitation.
Regardless of the technique used to insert the knee replacement (traditional or minimally-invasive) in the event that a total knee replacement requires re-operation sometime in the future it almost always can be revised (re-done) successfully. However results of revision knee replacement are typically not as good as first-time knee replacements.
There is good evidence that the experience of the surgeon correlates with outcome in total knee replacement surgery; for this reason it is best to have the initial surgery done by an individual who is experienced (fellowship-trained and with a practice that focuses on knee replacement) in this kind of work.
Likewise the new technique of minimally-invasive quadriceps sparing knee replacement should only be performed by surgeons who have taken special training on the instruments and surgical approaches and who have experience using less-invasive surgical techniques around the knee.
Surgeons with this level of experience have been shown to have fewer complications and better results than surgeons who haven’t done as many knee replacements. It is therefore important that the surgeon performing the technique be not just a good orthopedic surgeon but a specialist in knee replacement surgery and in less-invasive joint replacement.
Risks specific to knee replacement include infection (which may result in the need for more surgery) nerve injury the possibility that the knee may become either too stiff or too unstable to enjoy it a chance that pain might persist (or new pains might arise) and the chance that the joint replacement might not last the patient's lifetime or might require further surgery.
Minimally-invasive quadriceps-sparing total knee replacement is a new procedure. For this reason it is fair to say that the specialty will need to pay close attention to results to make sure they are as good or better than the traditional techniques that have been in common use for quite some time now. However preliminary studies on the technique have shown no increases in surgical or medical risk with this approach compared to traditional total knee arthroplasty and these same studies have shown benefits in terms of post-operative pain and early recuperation and rehabilitation after surgery.
While the overall list of complications may seem long and intimidating the overall frequency of major complications following total knee replacement is low usually less than 5 percent (one in 20). Obviously the overall risk of surgery is dependent both on the complexity of the knee problem but also on the patient's overall medical health.
The major apparent risks of the minimally-invasive quadriceps-sparing procedure compared to traditional total knee replacement include the following:
Again the overall likelihood of a severe complication is typically less than 5 percent when such steps are taken.
Patients undergoing total knee replacement surgery usually will undergo a pre-operative surgical risk assessment. When necessary further evaluation will be performed by an internal medicine physician who specializes in pre-operative evaluation and risk-factor modification. Some patients will also be evaluated by an anesthesiologist in advance of the surgery.
Routine blood tests are performed on all pre-operative patients; chest X-rays and electrocardiograms are obtained in patients who meet certain age and health criteria as well.
Some patients opt to predonate their own blood in advance of surgery to try to minimize the likelihood that transfusions from the blood bank will be needed. Each patient’s individual circumstances need to be considered when deciding whether this is worthwhile.
Surgeons will often spend time with the patient in advance of the surgery making certain that all the patient's questions and concerns as well as those of the family are answered.
Some patients have complex medical needs and around surgery often require immediate access to multiple medical and surgical specialties and in-house medical physical therapy and social support services.
Finding an experienced surgeon
Some questions to consider asking your knee surgeon:
Next a well-positioned skin incision – typically about 4” in length (see figure 19) though this varies with the patient’s size – is made down the front of the knee just adjacent to the kneecap and the knee joint is inspected and preliminary ligament balancing is performed.
Next specially-designed alignment rods and cutting jigs – which are smaller and easier to pass through the smaller incision than those used for traditional total knee replacement – are used to remove enough bone from the end of the femur (thigh bone) the top of the tibia (shin bone) and the underside of the patella (kneecap) to allow placement of the joint replacement implants. Proper sizing and alignment of the implants as well as final balancing of the knee ligaments all are critical for normal post-operative function and good pain relief. Again these steps are complex and considerable experience in minimally-invasive knee replacement is required in order to make sure they are done reliably case after case. Provisional (trial) implant components are placed without bone cement to make sure they fit well against the bones and are well aligned; at this time good function--including full flexion (bend) extension (straightening) and ligament balance--is verified.
Finally the bone is cleaned using saline solution and the joint replacement components are cemented into place using polymethylmethacrylate bone cement (see figure 20). The surgical incision is closed using stitches and staples.
Length of minimally-invasive (quadriceps-sparing) total knee replacement
Pain and pain management
Alternatively an epidural catheter (a very thin flexible tube placed into the lower back at the time of surgery) to manage post-operative discomfort. This device is similar to the one that is used to help women deliver babies more comfortably. As long as the epidural is providing good pain control we leave it in place for two days after surgery. After the epidural is removed pain pills usually provide satisfactory pain control. Patients who have epidural or spinal anesthesia can expect to walk with crutches or a walker and to take the knee through a near-full range of motion starting on the day after surgery. In the days that follow the patient is transitioned on to pain pills to allow rehabilitation and rapid recovery following minimally-invasive quadriceps-sparing total knee replacement.
Some patients are not candidates for spinal or epidural anesthetics or choose not to have them. These patients receive pain medications by vein for the first day or two and then can go home on pain pills following minimally-invasive quadriceps-sparing total knee replacement.
Use of medications
Aggressive rehabilitation is desirable following this procedure and a high level of patient motivation is important in order to get the best possible result. “Minimally-invasive” does not mean “non-invasive” or “minor”; it is important to realize that even with the newer technique the biggest key to recovery is a motivated patient who is diligent about his/her rehabilitation and home exercises. Pushing through a certain amount of discomfort or pain is part of recovery from any knee replacement.
Oral pain medications help this process in the weeks following the surgery.
Most patients take some narcotic pain medication for between 2 and 6 weeks after surgery. Patients should not drive while taking these kinds of medications.
Effectiveness of medications
Minimally-invasive quadriceps-sparing total knee replacement seems to be associated with less pain than traditional total knee replacement. However it is important to realize that it is a real surgical procedure and a good outcome depends on a motivated patients who is willing to push through a certain amount of discomfort to get the best possible knee motion and outcome after surgery.
Important side effects
The overall duration of hospitalization after minimally-invasive quadriceps-sparing total knee replacement typically is 48 hours; some patients need to stay for a third day but many do not. Patients generally are discharged directly home from the hospital after minimally-invasive quadriceps-sparing total knee replacement and don't require any inpatient rehabilitation. Ultimately the length of hospital stay is individualized to meet each patient’s needs and discharge occurs when the patient can perform the necessary range of motion exercises and when home support systems for the patient are in place.
Recovery and rehabilitation in the hospital
At the time of discharge the patient should be relatively comfortable on oral medications should have a dry incision should understand their exercises and should feel comfortable with the plans for managing the knee. Management of these limitations requires advance planning to accomplish the activities of daily living during the period of recovery.
Patients are encouraged to walk as normally as possible immediately following minimally-invasive quadriceps-sparing total knee replacements. Most people use crutches or a walker for a week and then a cane for another week or so beyond that. Most people are walking nicely by about two weeks after surgery (see video above).
Patients are allowed to shower as soon as the surgical incision has been dry for a day or so.
Patients should not resume driving until they feel their reflexes are completely normal and until they feel they can manipulate the control pedals of the vehicle without guarding from knee discomfort. Certainly patients should not drive while taking narcotic-based pain medications. On average patients are able to drive between three and six weeks after the surgery.
Can rehabilitation be done at home?
For patients who are unable to attend outpatient physical therapy home physical therapy is arranged.
Most people walk using crutches or a walker for 2 weeks then use a cane for about 2 more weeks.
Most patients obtain and keep at least 90 degrees of motion (bending the knee to a right angle) by a day or two after surgery and most patients ultimately get more than 110 degrees of knee motion.
Most patients can return to sedentary (desk) jobs by about 4 weeks; return to more physical types of employment must be addressed on a case-by-case basis.
Most patients are back to full activities--without the pain they had before surgery--by about two months after the operation.
Duration of rehabilitation
Returning to ordinary daily activities
Most patients can return to desk work at least for part days by about a three weeks after surgery.Sample Video
Long-term patient limitations
Permitted when the patient finds them comfortable:
Since the joint replacement includes a bearing surface which potentially can wear walking or running for fitness are not recommended. Some patients feel well enough to do this and so need to exercise judgment in order to prolong the life-span of the implant materials. Swimming water exercises cycling and cross country skiing (and machines simulating it like Nordic Track) can provide a high level of cardiovascular and muscular fitness without excessive wear on the prosthetic joint materials.
Summary of minimally-invasive (quadriceps-sparing) total knee replacement for knee arthritis
Minimally-invasive quadriceps-sparing total knee replacement is a new technique for implanting well-tested total knee replacement components while minimizing post-operative pain and the time to full recovery. The length of the surgical incision while not a goal of the procedure is about half as long using the minimally-invasive approach compared to traditional total knee replacement approaches. One needs to remember that this is a new technique and although preliminary studies are promising it is likely we will continue to learn more about this procedure as time passes and there may be risks to this approach that are not fully appreciated at this time.
Like any major procedure there are risks to total knee surgery and the decision to have a knee replacement must be considered a quality-of-life choice that individual patients make with a good understanding of what those risks are.
Knee replacement is a surgical technique that has many variables; like most areas of medicine ongoing research will continue to help the technique evolve. It is important to learn as much as possible about the condition and the treatment options that are available before deciding whether--or how--to have a knee replacement done. While many of the changes now being explored in the field of total knee replacement may eventually be shown to be legitimate advances – perhaps including alternative bearing surfaces – it is important to compare them carefully to traditional total knee replacement performed using well established techniques which we know are 90-95% likely to provide pain relief and good function for more than 10 years after the surgery.