knee pain

How is the knee designed, and what is its function?

The knee is a joint that has three compartments. The thigh bone (femur) meets the large shin bone (tibia) forming the main knee joint. This joint has an inner (medial) and an outer (lateral) compartment. The kneecap (patella) joins the femur to form a third compartment, called the patellofemoral joint.

The knee joint is surrounded by a joint capsule with ligaments strapping the inside and outside of the joint (collateral ligaments) as well as crossing within the joint (cruciate ligaments). These ligaments provide stability and strength to the knee joint.

The meniscus is a thickened cartilage pad between the two joints formed by the femur and tibia. The meniscus acts as a smooth surface for motion and absorbs the load of the body above the knee when standing. The knee joint is surrounded by fluid-filled sacs called bursae, which serve as gliding surfaces that reduce friction of the tendons. Below the kneecap, there is a large tendon (patellar tendon) which attaches to the front of the tibia bone. There are large blood vessels passing through the area behind the knee (referred to as the popliteal space). The large muscles of the thigh move the knee. In the front of the thigh, the quadriceps muscles extend the knee joint. In the back of the thigh, the hamstring muscles flex the knee. The knee also rotates slightly under guidance of specific muscles of the thigh.

The knee functions to allow movement of the leg and is critical to normal walking. The knee flexes normally to a maximum of 135 degrees and extends to 0 degrees. The bursae, or fluid-filled sacs, serve as gliding surfaces for the tendons to reduce the force of friction as these tendons move. The knee is a weight-bearing joint. Each meniscus serves to evenly load the surface during weight-bearing and also aids in disbursing joint fluid for joint lubrication.

What injuries can cause knee pain, and what other symptoms may accompany knee pain?

Injury can affect any of the ligaments, bursae, or tendons surrounding the knee joint. Injury can also affect the ligaments, cartilage, menisci (plural for meniscus), and bones forming the joint. The complexity of the design of the knee joint and the fact that it is an active weight-bearing joint are factors in making the knee one of the most commonly injured joints.

Ligament injury

Trauma can cause injury to the ligaments on the inner portion of the knee (medial collateral ligament), the outer portion of the knee (lateral collateral ligament), or within the knee (cruciate ligaments). Injuries to these areas are noticed as immediate pain but are sometimes difficult to localize. Usually, a collateral ligament injury is felt on the inner or outer portions of the knee. A collateral ligament injury is often associated with local tenderness over the area of the ligament involved. A cruciate ligament injury is felt deep within the knee. It is sometimes noticed with a "popping" sensation with the initial trauma. A ligament injury to the knee is usually painful at rest and may be swollen and warm. The pain is usually worsened by bending the knee, putting weight on the knee, or walking. The severity of the injury can vary from mild (minor stretching or tearing of the ligament fibers, such as a low grade sprain) to severe (complete tear of the ligament fibers). Patients can have more than one area injured in a single traumatic event.

Ligament injuries are initially treated with ice packs and immobilization, with rest and elevation. It is generally recommended to avoid bearing weight on the injured joint, and crutches may be required for walking. Some patients are placed in splints or braces to immobilize the joint to decrease pain and promote healing. Arthroscopic or open surgery may be necessary to repair severe injuries.

Surgical repair of ligaments can involve suturing alone, grafting, and synthetic graft repair. These procedures can be done by either open knee surgery or arthroscopic surgery (described in the section below). The decision to perform various types of surgery depends on the level of damage to the ligaments and the activity expectations of the patient. Many repairs can now be done arthroscopically. However, certain severe injuries will require an open surgical repair. Reconstruction procedures for cruciate ligaments are increasingly successful with current surgical techniques.

Meniscus tears

The meniscus can be torn with the shearing forces of rotation that are applied to the knee during sharp, rapid motions. This is especially common in sports requiring reaction body movements. There is a higher incidence with aging and degeneration of the underlying cartilage. More than one tear can be present in an individual meniscus. The patient with a meniscal tear may have a rapid onset of a popping sensation with a certain activity or movement of the knee. Occasionally, it is associated with swelling and warmth in the knee. It is often associated with locking or an unstable sensation in the knee joint. The doctor can perform certain maneuvers while examining the knee which might provide further clues to the presence of a meniscal tear.

Routine X-rays, while they do not reveal a meniscal tear, can be used to exclude other problems of the knee joint. The meniscal tear can be diagnosed in one of three ways: arthroscopy, arthrography, or an MRI. Arthroscopy is a surgical technique by which a small diameter video camera is inserted through tiny incisions on the sides of the knee for the purposes of examining and repairing internal knee joint problems. Tiny instruments can be used during arthroscopy to repair the torn meniscus.

Arthrography is a radiology technique whereby a contrast liquid is directly injected into the knee joint and internal structures of the knee joint thereby become visible on X-ray film. An MRI scan is another radiology technique whereby magnetic fields and a computer combine to produce two- or three-dimensional images of the internal structures of the body. It does not use X-rays and can give accurate information about the internal structures of the knee when considering a surgical intervention. Meniscal tears are often visible using an MRI scanner. MRI scans have largely replaced arthrography in diagnosing meniscal tears of the knee. Meniscal tears are generally repaired arthroscopically.

Tendinitis

Tendinitis of the knee occurs in the front of the knee below the kneecap at the patellar tendon (patellar tendinitis) or in the back of the knee at the popliteal tendon (popliteal tendinitis). Tendinitis is an inflammation of the tendon, which is often produced by a strain event, such as jumping. Patellar tendinitis, therefore, also has the name "jumper's knee." Tendinitis is diagnosed based on the presence of pain and tenderness localized to the tendon. It is treated with a combination of ice packs, immobilization with a knee brace as needed, rest, and antiinflammatory medications. Gradually, exercise programs can rehabilitate the tissues in and around the involved tendon. Cortisone injections, which can be given for tendinitis elsewhere, are generally avoided in patellar tendinitis because there are reports of risk of tendon rupture as a result of corticosteroids in this area. In severe cases, surgery can be required. A rupture of the tendon below or above the kneecap can occur. When it does, there may be bleeding within the knee joint and extreme pain with any knee movement. Surgical repair of the ruptured tendon is often necessary.

Fractures

With severe knee trauma, such as motor vehicle accidents and impact traumas, bone breakage (fracture) of any of the three bones of the knee can occur. Bone fractures within the knee joint can be serious and can require surgical repair as well as immobilization with casting or other supports.

What are diseases and conditions that can cause knee pain, and how are they treated?

Pain can occur in the knee from diseases or conditions that involve the knee joint, the soft tissues and bones surrounding the knee, or the nerves that supply sensation to the knee area. In fact, the knee joint is the most commonly involved joint in rheumatic diseases, immune diseases that affect various tissues of the body including the joints to cause arthritis.

Arthritis is inflammation within a joint. The causes of knee joint inflammation range from noninflammatory types of arthritis such as osteoarthritis, which is a degeneration of the cartilage of the knee, to inflammatory types of arthritis (such as rheumatoid arthritis or gout). Treatment of the arthritis is directed according to the nature of the specific type of arthritis. For more information on arthritis, please read the following articles: Psoriatic Arthritis and Reactive Arthritis.

Swelling of the knee joint from arthritis can lead to a localized collection of fluid accumulating in a cyst behind the knee. This is referred to as a Baker cyst and is a common cause of pain at the back of the knee.

Infections of the bone or joint can rarely be a serious cause of knee pain and have associated signs of infection including fever, extreme heat, warmth of the joint, chills of the body, and may be associated with puncture wounds in the area around the knee.

Tumors involving the joint are extremely rare. They can cause problems with local pain.

The collateral ligament on the inside of the knee joint can become calcified and is referred to as Pellegrini-Stieda syndrome. With this condition, the knee can become inflamed and can be treated conservatively with ice packs, immobilization, and rest. Infrequently, it requires a local injection of corticosteroids.

Chondromalacia refers to a softening of the cartilage under the kneecap (patella). It is a common cause of deep knee pain and stiffness in younger women and can be associated with pain and stiffness after prolonged sitting and climbing stairs or hills. While treatment with antiinflammatory medications, ice packs, and rest can help, long-term relief is best achieved by strengthening exercises for the quadriceps muscles of the front of the thigh.

Bursitis of the knee commonly occurs on the inside of the knee (anserine bursitis) and the front of the kneecap (patellar bursitis, or "housemaid's knee"). Bursitis is generally treated with ice packs, immobilization, and antiinflammatory medications such as ibuprofen (Advil, Motrin) or aspirin and may require local injections of corticosteroids (cortisone medication) as well as exercise therapy to develop the musculature of the front of the thigh.

Knee Pain At A Glance

• The knee joint has three compartments.
• Causes of knee pain include injury, degeneration, arthritis, infrequently infection, and rarely bone tumors.
• Ligaments within the knee (cruciate ligaments) and on the inner and outer sides of the knee (collateral ligaments) stabilize the joint.
• Surgical repair of ligament injury can involve suturing, grafting, and synthetic graft repair.
• Routine X-rays do not reveal meniscus tears but can be used to exclude other problems of the bones and other tissues.
• The knee joint is the most commonly involved joint in rheumatic diseases, which are immune diseases that affect various tissues of the body, including the joints, to cause arthritis.

Distinguishing among patellofemoral disorders

Stratifying by type of dysfunction helps clinicians make the diagnosis.

By Robert Afra, MD, and Anthony Schepsis, MD

Many classification systems have been devised to help clinicians understand and properly address patellofemoral dysfunction. However, no system has become uniformly accepted. As a result, there is no clear consensus about which therapeutic measures should be used for the various underlying pathologies that lead to patellofemoral problems.

In our opinion, grouping patients with patellofemoral dysfunction according to treatment strategy produces the most practical classification system. The major distinction to be made is between patellofemoral compression syndrome and patellofemoral instability.

Patients with patellofemoral compression syndrome present primarily with pain. They tend to have tight tissue that leads to excessive pressure between the patella and trochlea. Patients usually are treated with nonoperative measures, although operative procedures may be indicated.

Patients with patellofemoral instability complain of instability or pain or both. Instability concerns may manifest as frank patellar dislocation or may be more subtle (e.g., a patient with subluxation may feel the knee cap slip and slide during activities).

Pain complaints are similar to those by patients who have patellofemoral compression syndrome. First-time dislocation typically is managed nonoperatively if there is no loose body or osteochondral lesion; recurring instability is more likely managed with surgery.

Biomechanics

When the knee is in full extension, the patella sits on the supratrochlear fat pad lateral to the trochlea. As the knee moves from an extended to a flexed position, the contact area of the patella onto the trochlea shifts from distal to proximal.

For example, the trochlea articulates with the distal patellar and midpatellar articular surfaces at 10° to 20° and at 30° to 60° of knee flexion, respectively.¹ This concept is important when a physical therapy prescription is written as the location of chondral damage affects the range of motion in which strengthening exercises are performed.

If the tibial tubercle is significantly lateralized compared with the trochlea, the patellar tendon may exert a laterally directed force on the patella. This force vector may be quantified with CT scanning or clinically with measurement of the Q angle (the angle formed between the tibial tubercle, center of the patella, and anterior superior iliac spine; a Q angle greater than 20° is considered abnormal; see page 56).

Other force-producing factors that result in a laterally directed vector include femoral rotation, excessive femoral anteversion, and tight lateral retinacular tissue.

Symptoms

Pain. Patellar pain may manifest in the parapatellar area (just medial or lateral to the patella) or radiate to the back of the knee. Some authors have stated that they can distinguish between patellofemoral compression syndrome and patellofemoral instability based on the location of pain (personal communication, J. P. Fulkerson, 2006).

They relate lateral parapatellar pain with compression and medial parapatellar pain with instability. We have not found this association to be uniformly true.

Patients may present with posterior knee pain. In some cases, they enter a clinic with MRI results demonstrating a Baker cyst.

Discussing the diagnosis of patellofemoral disease with these patients becomes challenging because they are convinced that the pain is caused by the cyst.

Dye² attributed day-to-day changes in a patient with patellofemoral pain to a loss of patellar and peripatellar tissue homeostasis. He coined the term envelope of load acceptance, or envelope of function, to account for why the same load may lead to patellofemoral pain in one person and not in another, or even lead to pain in the same person at one time but not at another.³

The envelope of load acceptance is related to overuse or a discrete single event that is excessive. The loads transmitted across the knee vary according to complex factors, such as the dynamic center of gravity, rate of load application, and angles of flexion and rotation.⁴

A person who is out of shape, for example, tries to climb several flights of stairs for a workout. This level of activity may be beyond the range of acceptable physiological load across the joint, and patellofemoral pain may result. In this case, the pain is a result of overuse, although patellofemoral pain also may be caused by a discrete event (e.g., twisting a knee).

Another person does the same workout by climbing several flights of stairs but is well conditioned. In this person, this level of activity may be within the range of acceptable physiological load across the joint and patellofemoral pain might not result.

Thus, differing activity and conditioning levels of patients may lead to patellofemoral pain variability. More important, the envelope of load acceptance or function narrows after an injury; a previously well-tolerated activity can now cause pain. Because of the variances, rehabilitation with physical therapy should be tailored to individual patients.

Emphasizing this concept to patients is useful. A patient often is told that he or she has arthritis under the kneecap or that the kneecap has undergone wear and tear.

The patient’s immediate response may be that he or she didn’t have pain before doing a specific activity. An explanation that is easier for patients to understand is that there is irritation between the kneecap and the thigh bone groove (trochlea) on which the kneecap travels and that the patellofemoral pain resolves when the irritation has resolved.

Instability. Patients with patellar instability include those with recurring frank patellar dislocations and those with symptoms of subluxation. With subluxation, complaints of the patella being loose or slipping and sliding usually are made when it is in a position in which the femur internally rotates on a fixed, externally rotated tibia. Because this position is similar to that in which anterior cruciate ligament (ACL) tears occur, a clinician may mistake a patellar dislocation for an ACL tear.

Patients who have patellar instability present with tears of the medial patellofemoral ligament (MPFL). There may be exacerbating bony malalignment or dysplasia; patella alta; Q angle greater than 20º; tibial tubercle to trochlear groove distance greater than 15 mm; or trochlear dysplasia.

Long-term instability may lead to tissue contracture that may overlap with descriptions attributed to compression syndrome (tight lateral retinaculum), which is the result of a chronically displaced patella. Patients may describe symptoms of instability without complaints of pain.

Patients who have patellar instability may report episodes of pain with acute patellar subluxation or dislocations. The pain may result from an acute inflammatory process with soft tissue injury or bone injury (e.g., edema/bruise) or from an osteochondral fracture. A bone bruise typically is seen in the medial facet of the patella or in the lateral femoral condyle.

Patellar subluxation is not synonymous with knee buckling, or giving way, which occurs with patellofemoral pain—because of pain inhibition—as it does with meniscal pathology. In contrast, patellar subluxation or instability is a sense the patient has that the kneecap is slipping and sliding.

Nomura and associates⁵ reported that 95% of first-time patellofemoral dislocators sustained a cartilage injury; 72% demonstrated osteochondral patellar fragments, and 26% had articular damage of the lateral femoral condyle.

Several authors stated that the diagnosis was made with preoperative x-ray films in only 32% to 80% of patients with osteochondral fractures.^6,7

An MPFL tear is the essential lesion for patellar dislocation.⁸ The origin is in an area between the medial femoral epicondyle and the adductor tubercle. The insertion is at the proximal/medial aspect of the patella. The MPFL is superficial to the joint synovium.

Patellar dislocation risk factors

In a prospective study that evaluated a cohort of first-time patellofemoral dislocators and recurrent dislocators, Fithian and colleagues⁹ showed a 17% risk of a repeat dislocation after the first dislocation (similar to previously published results) and a 49% risk with a history of more than one previous dislocation.

At two to five-year follow-up, patients with a history of more than one dislocation had a 30% chance of contralateral patellofemoral dislocation, compared with 9% in patients with only one dislocation.

Girls aged 10 to 17 years were at highest risk for redislocation in both the first-time and recurrent dislocator cohorts. MRI findings at the time of the first dislocation associated with future recurrences are lack of edema in the vastus medialis obliquus muscle, MPFL midsubstance injuries, and MPFL femoral attachment injuries.

The chances of sustaining a dislocation were six times higher with a history of patellofemoral dislocation and four times higher with a family history. They were 15 times higher with a history of developmental dysplasia of the hip.

Larsen and Lauridsen¹⁰ reported that patella alta and lateral patellar displacement are significantly more common in patients with patellar dislocations who deny a history of trauma than in those who attribute the dislocation to trauma.

They also reported that patients who were younger than 20 years when they sustained their first patellofemoral dislocation tended to redislocate more than patients who were older than 20 years.

Generalized ligamentous laxity, initially described by Carter and Wilkinson,¹¹ has been shown to be a predictor of poor clinical outcome after realignment surgeries, procedures that aim to reef or tighten tissue or alter the vector of force.^12,13

The signs include dough-like skin consistency, elbow hyperextension, the ability to fold the thumb to reach the volar forearm surface, knee hyperextension, and the ability to touch the palms on the ground with the knees kept in extension.

Compression

Patellofemoral compression syndrome results from excessive tension or compression of soft tissue structures; exacerbating bony malalignment may be present.

A tight lateral retinaculum, for example, places the patella at risk for facing excessive compressive forces against the trochlea as the knee is flexed. If a shortened iliotibial band pulls posteriorly on the shortened lateral retinaculum, the patella faces even more profound compressive forces.¹⁴

These tightened structures lead to lateral tracking of the patella. In addition, a tight hamstring and tight gastrocnemius accentuate lateral patella tracking by increasing the dynamic Q angle.

Robert Afra, MD, is an assistant clinical professor in orthopedic surgery, division of sports medicine, at the University of California, San Diego. Anthony Schepsis, MD, is a professor of orthopedic surgery and chief, division of sports medicine, at Boston University.

A version of this article originally appeared in our sister publication, the Journal of Musculoskeletal Medicine, in June.

Foot orthoses play core role in treatment of plantar fasciitis

Practitioners prescribe different forms of orthoses, along with other nonsurgical modalities, for patients.

By Andria Segedy

The foot is critical for maintaining function, balance, and coordination while walking. However, thousands of Americans step out of bed every morning with an excruciating throbbing sensation in the foot and heel. Plantar fasciitis, a common form of heel pain related to microtearing or stretching of the plantar fascia, is one of the conditions most frequently seen by foot and ankle orthopedic surgeons, according to the American Academy of Orthopaedic Surgeons.

Nonsurgical treatment is effective for up to 85% of these patients.¹ The combination of foot and ankle stretching exercises, anti-inflammatory medication, patient weight loss, and the use of orthoses has proven to be a recipe for the successful treatment of plantar fasciitis. Current research is trying to determine the differences—or similarities—among over-the-counter, prefabricated, and custom-molded orthoses in treating plantar fasciitis.

“The condition of plantar fasciitis has stayed the same forever. What is changing is the technology to see what could be causing it,” said Matt Arciuolo, CPed, owner of Footstar Pedorthics Centers in Milford, CT.

Arciuolo predicts a hike in the number of plantar fasciitis cases in light of the trend in increased body weight in adults.

There is universal support for nonoperative treatment options for recalcitrant plantar fasciitis among practitioners, according to John G. Anderson, MD, an orthopedic surgeon with Orthopaedic Associates of Grand Rapids, MI, and a cochair of the Public Education Committee of the American Orthopaedic Foot and Ankle Society.

“Ideally, treatment modalities are those that take stress off the arch: good shoes, arch supports, stretching of the calf muscle and the plantar fascia, and weight loss,” he said.

One prospective randomized trial1 compared several nonoperative treatments for proximal plantar fasciitis, including custom and prefabricated orthoses. Researchers from the University of California, San Francisco, recruited 236 patients (160 women and 76 men) aged 16 years or older. Most had reported a duration of plantar fasciitis symptoms of six months or less.

The subjects were randomized prospectively into five treatment groups. All groups performed stretching of the Achilles tendon and plantar fascia in a similar manner. One group was treated with stretching only, while the other four groups stretched and used one of four shoe inserts. These were a silicone heel pad, a felt pad, a rubber heel cup, and custom-made polypropylene orthotic device. After eight weeks of treatment, patients were reevaluated and each group showed improvement. The silicone insert group improved by 95%; the rubber insert group, 88%; the felt insert group, 81%; the custom orthosis group, 68%; and the stretching only group, 72%.

Combining all the patients who used a prefabricated insert, researchers found that their improvement rates were higher than those assigned to stretching only (P = 0.022), and those who stretched and used a custom orthosis (P = 0.0074).

Researchers concluded that, when used in conjunction with a stretching program, a prefabricated shoe insert is more likely to produce improvement in symptoms as part of the initial treatment of proximal plantar fasciitis than a custom polypropylene orthotic device.

Pressure reduction

In San Antonio, data collection for a study that is evaluating the effects of foot orthoses on plantar pressures among people with diabetes should be completed by early September. The research is being overseen by Gordon Bosker, CPO, CPed, an instructor-researcher at the University of Texas Health Sciences Center and a clinician at the Texas Diabetes Institute.

The study, investigating three foot orthoses, might help establish better guidelines for practitioners providing optimal foot care to patients with diabetes.

The study calls for 42 participants to wear an extra-depth Brooks running shoe with a custom-molded trilaminar insert, a prefabricated trilaminar insert without modifications, or a contoured over-the-counter shoe insert made out of plastazote and polyurethane.

Ten more participants were added to the study to test a dynamic orthosis measuring device for plantar pressures, which is already on the market, according to Bosker. The device measures the plantar surface pressure when ambulating, and the data then get sent to the manufacturer for molding the custom insert.

“We are comparing the measuring device’s molded inserts with the three inserts in the original study,” he said. “With only 10 subjects, it’s just a pilot study to determine if more research is warranted.” Bosker presented a poster on the research at the Annual Meeting and Scientific Symposium of the American Academy for Orthotists and Prosthetists in February. Initial data show there are some benefits to the use of either OTC or custom-molded arch supports.“It would appear that for certain areas of the foot, a custom insert is more effective than an over-the-counter version because it reduces the pressure load,” Bosker said. “But because this is the early research stage, we don’t know if it is a trend.”

In the study, the foot was divided into five sections: heel, midfoot, first to third metatarsal, fourth to fifth metatarsal, and the great hallux. Several of these areas responded better to customized inserts than to the others.

“We are seeing some positive results with a full-foot orthosis that affects the first to third metatarsal, midfoot, and heel,” he said. “That’s not a surprise, but there is very little research to support this. We are attempting to solidify what has been researched to treat the diabetic patient.”

The results to date have shown that the OTC insert is effective in certain parts of the foot, such as the heel, especially for diabetic patients, according to Bosker.

“For other specific problems like meta­tarsal pressure, it would appear that we would need to have the custom-molded insert,” he said.

The material used to make a custom-molded insert needs to be further re­searched. Bosker and his team are in the process of securing funding for an investigation to determine the best materials for the custom-molded insert.

Patient evaluation

At Breakthrough Podiatry in Merrillville, IN, clinicians see a lot of patients who have had heel pain ranging from six months to many years, according to owner Bruce Williams, DPM, the current president of the American Academy of Podiatric Sports Medicine.

“We have a 95% to 98% rate of success in relieving pain when we use foot and ankle manipulation along with stretching exercises to increase the range of motion in the ankle joint,” he said. “I use Dr. Howard Dananberg’s technique when manipulating the ankle joint for patients who have a functional decrease in ankle joint dorsiflexion range of motion.”

Dananberg’s method of ankle manipulation, in basic terms, involves initially adjusting the fibula head in a posterior to anterior manner. Then, the practitioner adjusts the talar head in an anterior to posterior fashion.

Williams follows up the manipulation by having the patients perform gastrocnemius and soleus stretching exercises to maintain the range of motion as much as possible. He also provides plantar fasciitis patients with a custom foot orthosis, which helps to eliminate pain in most of them within three to five patient visits.

For patients who continue to have pain, Williams will use an in-shoe pressure analysis, or F-scan, to pinpoint problems in foot mechanics. He will then modify the prescription of the patient’s custom foot orthosis.

“In my practice, I use custom-made devices the majority of the time instead of over-the-counter devices,” Williams said. “Most insurance companies will cover the custom-made devices, and I feel this will provide my patients with the most specific adjunct in alleviating their foot and ankle pain.”

In some instances, Williams will use OTC devices. But he often ends up altering even those.

“Unfortunately, I usually have to modify most of these devices to achieve the specific effects I want in treating patients’ functional foot and ankle problems,” Williams said.

Arciulo also relies on in-shoe pressure mapping of his patients’ feet before he can prescribe an orthosis. The mapping helps him evaluate where excessive pressures are being applied in the foot.

“By using orthoses, you can take upwards of 20% of the pressure off the heel by raising the arch, because the arch is taking more of the weight,” he said.

Also, by slightly raising the heel, the patient’s center of mass can be brought slightly forward, which reduces pressure on the heel, according to Arciuolo. If the center of mass is brought too far forward, however, it can exacerbate metatarsal issues.

Materials matter

Material choices for orthoses for plantar fasciitis depend on the patient’s needs and preferences and the potential for secondary complications.

Some patients with plantar fasciitis may require really soft orthoses, particularly those with diabetes or who have poor sensation, according to Anderson. For individuals with normal sensation, a semirigid or semiflexible orthosis made of foam, cork, or a composite material is often better tolerated.

“Our experience tells us the use of a nonrigid device—something semirigid or flexible—is better tolerated by patients with plantar fasciitis than a rigid plastic device,” said Lowell Weil, Sr., DPM, medical director of the Weil Foot & Ankle Institute in Des Plaines, IL. “Rigid does a good job if there is pain in the legs, ankles, and sometimes in the heels.”

In addition to running the Weil Foot & Ankle Institute, which has 11 locations throughout the Chicago area, Weil is the team podiatrist for the Chicago White Sox. Each year, he and his staff see about 1500 new patients with plantar fasciitis.

Weil believes that the use of a deep heel cup is very important in helping to support the hydraulic structure of the heel. Given a choice, patients opt for a softer device, which is bulkier and cannot be worn in a nice shoe, he said. An orthosis made from softer materials such as cork, leather, or plastazote is best worn in a running shoe.

Weil recently started offering a Vasyli orthosis, which is fabricated on the spot. The device’s neutral shell can be modified to the patient’s foot. The orthosis is low profile, or thinner than most orthoses, and comes in several designs that can be modified with a heat gun. The only drawback to the Vasyli orthosis is that it tends to wear out faster than the laboratory-produced orthosis, which has a life of 10 to 15 years, according to Weil.

In addition to the various orthotic materials now available, there are many ways to combine all these elements to make an orthosis work effectively for patients with plantar fasciitis.

“There’s no one method to fix plantar fasciitis,” Arciuolo said. “I can do the same orthotic style for five patients, and they will all have different outcomes. Some respond better to stretching, some to cushioning, and others to support.”

Exercise can offset a predisposition to excess weight

by naveen chowdary

Though genetics do play a role in obesity, a new study shows that regular physical activity can offset the impact of a predisposition to being overweight.

The study investigated whether variations of a particular gene, known as the fat mass and obesity associated (FTO) gene, are linked with a high body mass index (BMI) in Old Order Amish individuals.

It also examined whether the detrimental associations of FTO gene variants can be lessened by an increase in physical activity. The University of Maryland study was published in the August issue of the Archives of Internal Medicine.

Seven hundred and four healthy adults with valid genotype data were selected from a sample group who had participated in the Heredity and Phenotype Intervention (HAPI) Heart Study, an investigation of gene vs. environmental interactions in cardiovascular disease.

Participants were members of the Older Amish community of Lancaster County, PA. Because of simi larities in tradition, formal education, and geographic location, the Old Order Amish have a relatively homogeneous lifestyle, including dietary habits.

Most men are farmers or work in physically demanding occupations. Women are homemakers and usually take care of many children. The mean age of the participants was 43.6 years. The study included slightly more men than women (53% male vs. 47% female).

Subjects who were defined as overweight had a BMI ≥25, and those who were considered obese had a BMI ≥30. The mean BMI was higher in women than in men. Additional measures of other obesity-related traits were obtained, including waist circumference and body composition (fat mass, lean mass, and derived percentage of body fat). The prevalence of overweight and obesity in the Amish men was 54.0% and 10.1%, respectively; in women, it was 63.7% and 30.5%, respectively.

Physical activity measurements were taken for each participant for seven consecutive 24-hour days. Based on these findings, researchers were able to compare the genotype associations of FTO variants in the Amish subjects in terms of “high” and “low” physical activity levels.

For women, mean energy expenditures were 2610 kilocalories per day for the low-activity group and 3590 kcal/day for the high group. For men, average energy expenditure for the low-activity group was 3130 kcal/day, compared with 3990 kcal/day for the high group.

Re searchers reported that activity levels in the high-activity stratum were approximately 900 kcal higher than in the low-activity one. High-level activities consisted of three to four hours of moderately intense physical activity, such as brisk walking, housecleaning, or gardening.

A DNA sequence variation—in the form of single-nucleotide polymorphisms  (SNPs)—asso ci a ted with BMI and related measures were seen only among the less physically active subjects.

By contrast, in the more physically active group, the FTO variant associations were much smaller and not statistically significant. Because the FTO geno type was not associated with physical activity, this finding suggests a strong moderating effect of physical activity on the deleterious effects of FTO variants, according to the researchers.

The study also reported that participants with certain variations of the FTO gene were more likely to be overweight. But the function of the FTO gene is still not completely understood, and its variants are prevalent, according to lead author Evadnie Rampersaud, MSPH, PhD.

In fact, about 30% of European populations have such variants, which are associated with a greater than 20% risk for obesity, she said.

“Weight increase resulting from the presence of these SNPs is much smaller and not statistically significant in subjects who are very physically active,” said Ram per saud. “This finding offers some clues to the mechanism by which FTO influences chan ges in BMI and may have im portant implications in targeting per son alized life style recommendations to prevent obesity in genetically susceptible individuals.”

More research is needed to determine the amount of activity required to negate the effect of an FTO-related genetic predisposition to weight gain, according to Rampersaud.

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