FAQ Category: Knee

There is some convincing evidence that altered kinematics is a major factor in patellofemoral pain syndrome (PFPS). Kinematics refers to patterns of movement — specifically how the patellofemoral joint and the knee joint rotate and glide in relation to one another during motion.

The patellofemoral joint occurs where the patella (kneecap) glides up and down over the femur (thighbone). Increased pressure from contact between the patella and the femur can lead to PFPS. This is called retropatellar stress — it means behind the kneecap.

Stress on the patellofemoral joint is made worse by rotations of the lower leg during weight-bearing activities. And repetitive actions with weight-bearing load during running and jumping increase retropatellar stress. The result is PFPS.

The mechanical factors that cause PFPS are likely present when you do the particular activities you are practicing. So doing more of them can make the problem worse. Altered hip and knee motion during weight bearing activities seems to be the main culprit.

Studies show that in athletes with PFPS (especially female athletes), there is an external rotation movement that occurs in the knee during single-leg squats and jumps. Evidently, this motion is not present in athletes who don’t have PFPS.

A closer look at the dynamics of movement has shown that when it comes to PFPS, changes in hip motion may be just as important as what the knee is doing. It appears that athletes who adduct the hip (knee moves toward the other knee) during single-leg squat motions have a greater tendency to develop PFPS. PFPS is more likely to occur if the knee externally rotates at the same time. The overall pattern of motion is one of medial collapse, sometimes referred to as dynamic knee valgus.

Training to stabilize the hip and retrain the knee to reduce the amount of external rotation during weight-bearing activities may be the answer. Physical therapists are actively studying this problem and looking for a solution. Someday, it may even be possible to identify athletes at risk for PFPS and put a stop to it before it even starts.

Patellofemoral pain syndrome (PFPS) is probably the biggest cause of knee pain in young athletes. And as you may have heard, girls are affected more often than boys. The average individual (male or female) isn’t usually plagued by this problem. It seems to come on with regular running and jumping activities.

Repetitive stress on the back of the kneecap where it moves up and down against the femur (thighbone) seems to be the major risk factor. This area is called the patellofemoral joint. But studies show that PFPS is a multifactorial problem. This means that more than one thing has contributed to the development of this condition.

Some of the problem could be genetic. But it’s likely that there are also neurologic, mechanical, and activity-related risk factors. Each one of these variables has an individual effect on the joint. A series of more recent studies has focused on the role of altered kinematics in PFPS.

Kinematics refers to patterns of movement — specifically how the patellofemoral joint and the knee joint rotate and glide in relation to one another during motion. It appears that females who adduct the hip (knee moves toward the other knee) during single-leg squat motions have a greater tendency to develop PFPS. PFPS is more likely to occur if the knee externally rotates at the same time.

Researchers are using three-dimensional (3-D) analysis in motion labs to figure out exactly what’s going on and what to do about it. Hopefully in the future, we will be able to predict who might develop this problem and prevent it (or at least treat it effectively when it does happen).

Many patients are afraid to attempt kneeling on their partial knee replacement. There is a concern that they might damage the new joint. And for those people who can no longer kneel before the surgery, there is the nagging fear that once they get down on the knee, they won’t be able to get back up.

Until recently, we weren’t even sure why patients couldn’t kneel after this surgery. There was wide speculation that it could be the location of the scar, pain, loss of knee motion, and/or numbness from nerve damage. But a study by physical therapists has shed some new light on this problem.

Practice kneeling (getting down and getting up) under the guidance of a physical therapist was very helpful in restoring this valuable skill. The therapist showed them how to kneel on a soft mat using arm support to aid in getting up and down. Kneeling was done on both knees. Limited knee flexion prevented sitting back fully on the heels. The therapist also offered feedback on proper posture and alignment and answered any questions the patients had.

There was no link between scar position, numbness, and range of motion and a change in kneeling ability. Sensitivity of the knee near the kneeling area from nerve injury was unpleasant, but didn’t affect kneeling ability. It appears that the key factors were to reduce fear and provide direction on how to kneel safely and easily.

Patient range-of-motion was not significantly different before and after surgery. This finding suggests that a loss of motion is not the reason patients can’t or don’t kneel after partial knee replacement. And problems in other joints were not a barrier to kneeling. Patients with arthritis in other joints reported being able to kneel using the therapist’s suggestions.

For older adults who want to play with grandchildren on the floor, it may be helpful to place yourself close to something you can use to lower yourself down and pull yourself back up. This could be a kitchen chair, the couch, or doorknob or handle. Until you practice enough to become sure of yourself, you may want to stay off the floor slightly. You can use a low chair (also placed strategically so you can get up and down.

But before trying this skill, make sure your orthopedic surgeon approves. Not all implants are designed for kneeling. You may want to schedule a follow-up appointment with the therapist who helped you with your rehab. Having a supervised session may be the best way to accomplish this task safely and easily.

Not necessarily. If the surgeon approved kneeling, she just may need a little help getting started. Kneeling is not possible with all implants. At least one study has shown it is okay to kneel with the Oxford® Partial Knee Replacement from Biomet Orthopedics. This partial knee implant was first approved for use in the United States by the Food and Drug Administration in 2004. Since then, it has become increasingly more popular.

It is designed to repair only the medial side of the knee (side closest to the other knee). About one in four patients with osteoarthritis have limited knee arthritis, known as medial compartment arthritis. A partial knee replacement replaces only one side of the knee joint. A total knee replacement removes all the knee joint surfaces.

Some advantages of the Oxford® partial knee replacement are that it removes 75 per cent less bone and cartilage than a total knee replacement. The implant is much smaller than a total knee implant. And the knee is less painful afterwards making recovery much faster.

By keeping all of the undamaged parts, the joint may bend and function more naturally compared to a total knee replacement. In theory, kneeling should be possible when it might not be allowed with other types of implants.

Many patients need a little help learning how to do this activity. If they have arthritis in other joints, a soft pad placed under the knees helps. Using the arms to support and guide the body down into the kneeling position is one other technique that helps. Patients are cautioned to put weight on both knees at the same time.

If you do not feel comfortable helping her regain this valuable skill, then consider making one or two appointments with the physical therapist. Education and supervised intervention after a partial knee replacement can make a difference. Practice kneeling (getting down and getting up) under the guidance of a physical therapist is very helpful in restoring this valuable skill.

The treatment of meniscus injuries has progressed and changed over the years. Meniscectomy (removing the meniscus) was the first procedure used. But long-term studies showed degeneration of the joint cartilage as a result. Meniscal repair is now performed whenever possible.

Symptoms such as knee swelling with activity, crepitus, and pain along the joint line can occur after meniscectomy (removal of the meniscus). Crepitus is the snapping or crackling felt or heard in the joint. When persistent pain with any of these other symptoms occur post-meniscectomy, a chondral defect (lesion in the joint cartilage) is suspected.

You may want to see your orthopedic surgeon for a follow-up exam. X-rays or more advanced imaging will show the location, size, and depth of any chondral defect. There are surgical procedures available now to repair and restore this layer of cartilage.

Meniscal autologous transplantation (MAT), osteochondral allograft(OA), andautologous chondrocyte implantation (ACI) are three of the newer repair methods. MAT repairs the meniscus. OA and ACI are used to repair damage that goes deeper into the cartilage layer underneath the meniscus.

Meniscal allograft transplantation (MAT) is a fairly new way to repair (rather than remove) damaged meniscus in the knee. It is an example of how the treatment of meniscus injuries has progressed and changed over the years. Meniscectomy (removing the meniscus) was the first procedure used. But long-term studies showed degeneration of the joint cartilage occurred as a result.

Researchers have been able to discover a way to transplant meniscal cells to help repair damaged areas of the meniscus. The transplanted cells can come from a healthy part of the patient’s own meniscus. This would be called an autologous transplant. Cells harvested from a donor can also be used. This type of transplant is called an allograft.

Rehab would be the same following either type of meniscal transplantation (autologous or allograft). According to a recent study from the Navy Medical Center in Bethesda, Maryland, a six-week rehab protocol begins with nonweight-bearing exercises using a continuous passive motion(CPM) machine.

The leg is placed in the CPM. The device slowly and steadily bends and straightens the knee joint. The amount of movement is regulated and progressed by five- to 10-degrees at a time. The unit is used for two hours at a time, and then the patient is given a rest. The patient spends a total of six to eight hours a day using the CPM. When out of the CPM device, the patients wear a hinged-knee brace with the knee held in a straight position.

The CPM unit is discontinued when the patient has 90-degrees of knee flexion. The brace is unlocked to allow some motion at the end of four weeks. Increasing amounts of active knee flexion are allowed as muscle control is improved. A physical therapist will guide you through this process. Patients are expected to regain full motion in eight to 12-weeks. With consistent attention to a home program, strength, motion, and function are fully restored by nine to 12-months.

Studies show that athletes involved in noncontact jumping sports have the highest rate of anterior cruciate ligament (ACL) injuries. The main mechanism of injury is called plant-and-cut maneuvers. There is too much load on the knee with the foot planted on the ground while the player changes direction quickly.

Dancers do have far fewer ACL injuries compared to athletes involved in jumping activities. The difference may be because dancers perform many more jumps in a daily 90-minute technique class compared to a 90-work-out on the basketball court.

The rigorous dance training may be enough to prevent ACL injuries. This is true even though load on the knee during jump landings in dance can put up to 12 times the dancer’s body weight in force on the knee joint. Dance training focuses on balance, alignment, footwork, and control. All of these skills may improve balance to a precise level needed to land single-leg jumps without injury.

Unlike athletes who don’t know what will happen next on the court, dancers practice the same steps in a routine. There are no surprise or unexpected movements to respond to. Basketball players collide with each other often. Contact with another dancer is rarely the cause of an ACL injury.

Practice, timing, alignment, balance, and posture may be the key factors. A focus on these variables during basketball practice may help reduce injuries in athletes involved in jumping activities.

You may be referring to supports used to help prevent or relieve pain from injuries during athletic events such as football, basketball, baseball, soccer, and volleyball. The commonly used knee strap is often seen on athletes with knee disorders such as chondromalacia patella, Osgood Schlatter’s disease, and runners and jumper’s knee.

You may even see older adults with arthritis and knee degeneration using such supports. In the case of the knee strap, it stabilizes and tightens up the patella (kneecap) by putting pressure on the patellar tendon just below the kneecap. This can help reduce inflammation and improves stability of the knee. This type of support can help keep the knee from giving out from under you. Many people can regain enough normal mobility that they are able to return to their regular activities.

The upper arm strap you see on athletes is worn above the biceps or triceps muscle. It puts pressue on the tendon fibers to help keep them from pulling and tearing. Sometimes swimmers use these to prevent painful swimmer’s arm. Anytime athletes participate in sports involving over use of the arm, the strap can help reduce the risk of painful tendinitis.

PFPS causes pain around and under the patella (kneecap). Activities that increase the load on this joint aggravate the condition. For example, many patients with PFPS report that walking, running, and using stairs make their symptoms worse. Moving the knee after a long period of sitting can also cause pain.

Nonpharmacologic treatment for this problem include exercise therapy, manual therapy, and ultrasound or other physical agents. It sounds like you’ve tried the most common conservative treatment for PFPS. Specific exercises, taping, and manual therapy to mobilize (move) the patella have some reported success. A more recent study has been published that also supports the need to strengthen hip muscles (abductors and external rotators).

Taping may be helpful but at present, there are no high quality reviews of studies to provide evidence supporting patellar taping. This does not necessarily mean taping does not work for this problem. Many athletes and active young adults with PFPS seem to find the best results using a combination of treatment methods.

The same group of interventions doesn’t always work for everyone. It usually takes a period of trial and error to find the right mix for each person. A physical therapist can help you with this. The therapist will evaluate you carefully for any postural, neuromuscular, or structural causes of your PFPS.

Treatment begins with efforts to restore normal flexibility, alignment, strength, and endurance. Adjustments to the treatment program and progression of the exercises should include specific sports training to help you advance in your athletic pursuits.

Actually, there has been some debate about whether oral contraceptives (birth control pills) may increase the risk of knee (anterior cruciate ligament or ACL) injuries. Scientists are studying whether or not ups and downs in hormone levels could be a risk factor for ACL injuries.

The basis for the possible link between hormones and knee injuries was discovered several years ago. Researchers found receptors on ACL for two hormones: estrogen and relaxin. Relaxin does produce a relaxation effect on ligaments. But the exact meaning of this relationship remains unknown.

A recent study comparing women taking oral contraceptives and who had ACL injuries with women taking oral contraceptives without ACl injuries did not find any effect caused by the birth control pills. All the women included in the study were either dancers or jumping athletes.

What they did find was that dancers had a low rate of ACL injuries. The authors offered several theories for the low rate of ACL injuries among dancers. First, dance training focuses on balance, alignment, footwork, and control. All of these skills may improve balance to a precise level needed to land single-leg jumps without injury. Second, dancers practice hundreds of jumps every day.

Third, jump practice progresses over time with supervision and guidance of an experienced dance instructor. And finally, unlike athletes, dancers practice the same steps in a routine. There are no surprise or unexpected movements to respond to. Rarely is there contact between two female dancers to cause an ACL injury.

The low incidence of ACL injuries among dancers points to different training techniques between dancers and other athletes. For dancers, monitoring fatigue and focusing more attention on reducing fatigue may be of benefit. Taking oral contraceptives is not advised for the purpose of preventing injuries.

Your first step should be to see your doctor for a follow-up exam. There may be a treatable reason for the knee instability you are experiencing. You many need a second course of physical therapy. An ongoing home program of exercise and activity modification may be required.

Frequent giving way of the knee suggests knee joint instability. An arthroscopic exam and/or X-rays may be helpful in diagnosing the problem. It’s possible there is a secondary meniscal tear. Or the ACL tear has become unstable resulting in this problem.

Sometimes, despite all efforts to avoid surgery, an operative procedure to repair the problem is really the best course of action. The long-term effects of any treatment approach selected should be considered. Chronic knee instability can lead to further injury. Some type of early intervention may help prevent future problems.

Different orthopedic surgeons may assess meniscal tears slightly differently. A minor tear may be one that repairs itself without surgery. The body has a limited ability to heal itself when the damage is not too severe. In the case of a meniscal tear, a partial tear that only involves part of the meniscus or a tear that doesn’t go through the full thickness of the meniscus may be labelled minor.

The surgeon can use an arthroscope to look at the full extent of the injury in order to advise the patient whether to repair or remove the torn cartilage. Location, depth, and extent of the injury are all evaluated and considered in the diagnostic process.

Meniscal tears and meniscectomy (removing a torn meniscus) are both risk factors for developing osteoarthritis of the knee. So care is taken to try and rehab first, repair second, and remove only if necessary.

Surgery is done in the most antiseptic conditions possible. All instruments used during surgery are sterilized, disposable equipment is all sealed until use, and the surgeons and nurses are covered in sterile clothing and use sterile gloves whenever they may have to touch the patients. They also wear masks to keep from coughing or sneezing, or even just breathing, germs into the air. As well, the ventilation system is specially designed to not allow “dirty” air into the operating room.

Despite all those precautions, infections can still happen. Sometimes the cause can be found, other times it can’t. One common reason for an infection in a joint replacement is if the patient already has an infection somewhere else in the body. It doesn’t have to be obvious and no-one may even be aware of it.

Many patient have to wait a while before they finally get their surgery date and they prepare for the surgery. Unfortunately, if they do have an infection, it’s very likely the surgeon will postpone the surgery. This is very upsetting if you’ve been waiting, so some people may be tempted to not alert the surgeon to the infection. This can be dangerous and result not only in an infection in the joint, but in life-threatening complications.

Any surgery has risks and the bigger the surgery, the more the risk. A knee replacement is a fairly routine surgery for orthopedic surgeons, but it’s still a major surgery.

Most of the possible complications are the same for just about any other surgery: infection, blood clots in the legs, and pneumonia (if you can’t get up and about, and can’t do the deep breathing exercises after having a general anesthetic). Complications specific to the replacement is loosening of the prosthesis, weakness or breakdown of the bone around the replacement, and stiffness in the knee.

With today’s improved surgical technology, patients have the option of bilateral total knee replacement (TKR) at the same time. This can be done by one surgical team doing both knees (first one, then the other) in the same operation. Or there can be two surgical teams working on both knees at the same time.

There are some concerns to consider. The overall rate of complications is greater for bilateral TKR compared with unilateral or staged bilateral procedures. Staged bilateral refers to having both knees replaced but they are done one at a time with a certain time interval (weeks to months) between procedures. The number of patients sent to the intensive care unit (ICU) is higher with simultaneous TKRs. The number of days they stay in ICU is also greater for bilateral versus unilateral TKR.

The risk of cardiac complications in patients having bilateral TKRs is four times the risk for those having one knee done. The risk of heart problems increases with age. There are several reasons for this. Heart disease is more common as we age. And the heart and lungs have less reserve capacity to respond to the stress of surgery.

On the plus side, there is less anesthesia used with bilateral simultaneous TKRs. Improved surgical technique means less blood loss. And rehab has to be done for both knees anyway. So the total length of time in recovery is less. There are fewer days of pain and a shorter hospital stay with fewer costs.

When making the decision to replace both knees at the same time, there are many factors to consider. Your overall health and the presence of any other medical problems or conditions must be weighed in the decision-making process.

It has been suggested by many researchers based on results of studies that bilateral knee replacements are best done in high-volume hospitals by an experienced surgeon. Usually such facilities also have adequate intensive care units to care for patients who need close monitoring. Hospital staffing of nurses, operating room tech support, and experience of surgeon and staff are all important points.

A frank discussion with your surgeon and your physical therapist will help direct your decision. Don’t hesitate to bring up your family’s concerns. You will benefit from the experiences of other patients and families who have already had this procedure done.

With today’s improved anesthesia and postoperative care, patients have the option of bilateral total knee replacement (TKR) at the same time. This can be done by one surgical team doing both knees (first one, then the other) in the same operation. Or there can be two surgical teams working on both knees at the same time.

An alternative approach is to have a staged bilateral procedure. Staged bilateral refers to having both knees replaced. But they are done one at a time with a certain time interval (weeks to months) between procedures.

However it’s done, it has been suggested by many researchers based on results of studies that bilateral knee replacements are best done in high-volume hospitals by an experienced surgeon. Usually such facilities also have adequate intensive care units to care for patients who need close monitoring.

Each surgeon has his or her own techniques and postoperative management measures. Steps can be taken during and after surgery to prevent complications. For example, the surgeon tries to avoid making too large of a hole in the shaft of the bone to insert the implant.

Improved surgical techniques are helping to reduce the number of fat emboli that cause postoperative problems. When the bone is cut open, a glob of fat from inside the bone marrow can enter the blood stream. The embolism can travel to the heart or brain causing serious problems such as death, heart attack, or stroke. Suctioning of the hole where the implant will go helps cut down on the number of fat emboli that occur.

Newer techniques to minimize blood loss, reduce stress on the heart and lungs, and prevent other complications have made this kind of surgery possible.

More and more bone and joint surgeries can be done on an outpatient basis these days. As a result, it has been necessary to improve pain management. One of the more popular and successful tools is the intra-articular pain pump.

These pumps are designed to deliver a small but steady amount of pain medication right at the site of the surgery. Patients do get good pain relief. They also use fewer narcotic drugs.

There are very few problems using these pumps. The most commonly reported complication is chondrolysis. Chondrolysis is a break down of the chondrocytes (cartilage cells) that line the joint.

Efforts are being made to study human joints and how they respond to medications dispensed via a pain pump. The most commonly used drugs include lidocaine and bupivacaine with or without epinephrine. Epinephrine is a stress hormone also known as adrenaline. It has the effect of increasing blood supply to the affected area. This can help speed up healing times.

A recent study has shown that epinephrine has a negative effect on chondrocytes. It appears that epinephrine may actually cause the death of many chondrocytes. Low doses of lidocaine or bupivacaine without epinephrine can be used safely and effectively for up to 48 hours. Most patients stop using the pain medication after the second day anyway.

Pain pumps are used now to deliver drugs directly to the joint. The pump is designed to make it possible to release a small amount of numbing agent and narcotic to the surgical site. The goals are good pain relief and less need for strong narcotic medications.

They seem to work well, especially in the first 24 to 48 hours. Patients are able to sleep better and function better. Some studies show faster recovery in rehab. With less pain, the patient can move better and with less stiffness and fewer compensatory movement patterns.

It sounds like your previous experience went well for you. But many times we don’t recall the extent of pain and dysfunction experienced years before. So give it a try at least for 24 hours and see how you like it. Anything that gets you up and moving again is worth a second look.

Hamstring injuries are very common among athletes and sports participants. They can be very mild or very disabling. Sprinters are especially susceptible. At full speed, the hamstring muscle contracts very fast to generate power needed for the run.

During sprinting, the hamstrings swing the thigh forward while bending the knee at the same time. When everything is in balance, the body’s center of gravity moves forward very smoothly and very quickly.

Any muscle deficit or imbalance of the hamstrings as they function in both capacities (as hip extensors and knee flexors) can lead to an injury. Olympic contenders have finely tuned bodies. They train every day and benefit from the expert advice of their trainers and coaches. The benefit of these counselors keeps the athlete in top shape and in the game (or in this case, on the track).

If there was a preseason loss of muscle strength in either concentric hip extension or eccentric knee flexion, the risk of a hamstring injury goes up. Concentric refers to muscle contractions as the muscle is shortening. An eccentric contraction is the action of a shortened muscle lengthening.

The length of time it takes to recover from a muscle injury depends on many factors. The degree of injury (mild sprain to complete rupture), strength, and flexibility all contribute to recovery. Other factors such as nutrition, fatigue, and intensity of preinjury training schedule can make a difference.

The 400 meter is the longest of the track events for sprint. Even though it still qualifies as a sprint event, the length of the course requires power, speed, and good technique. The runner has to break fast and push hard until the straight part of the track is reached. The pace is a little more relaxed but picks up again with increasing speed toward the finish line.

Hamstring injuries are very common among athletes and sports participants, especially sprinters. They can be very mild or very disabling. Throughout the race, the hamstring muscle carries out two functions.

It contracts concentrically to extend the hip and eccentrically to flex the knee. Concentric refers to muscle contractions as the muscle is shortening. An eccentric contraction is the action of a shortened muscle lengthening.

At full speed, the hamstring muscle contracts very fast to generate power needed for the run. If there is a preseason loss of muscle strength in either concentric hip extension or eccentric hip flexion, the risk of a hamstring injury goes up.

If you are working with an athletic trainer or physical therapist, it would be a good idea to have some muscle testing done. Any muscle deficit or imbalance can be addressed. Training should include weights, circuit training, leg and arm conditioning, plyometrics, and extensive stretching exercises.