Pes anserinus bursitis (also referred to as anserine or pes anserine bursitis) is an inflammatory condition of the medial knee. Especially common in certain patient populations, it often coexists with other knee disorders.[1, 2] Diagnosis of pes anserine bursitis should be considered when there is spontaneous pain inferomedial to the knee joint.
Bursae are small synovial tissue–lined structures that help different tissues glide over one another, as when a tendon slides over another tendon or bone. Bursae may become painful when irritated, damaged, or infected. The pes anserinus (anserine) bursa, along with its associated tendons, is located along the proximomedial aspect of the tibia.
Community-dwelling older adults can also present with complaints of knee pain in which pes anserine bursitis and other nonarticular conditions may play a role. Sporting activities, diabetes, obesity, and female sex are also associated risk factors that have been reported.
Pes anserine bursitis is primarily a self-limiting condition, which responds well to an exercise/stretching program.[3] Recalcitrant cases should be referred to a specialist to confirm the diagnosis and to rule out other causes of the patient’s pain (eg, proximal tibial plateau stress fracture).
Typical findings in patients with pes anserine bursitis may include the following:
Pain and tenderness over the inner knee
Local swelling
Chronic refractory pain in the area during aggravating activities in individuals with arthritis of the knee or in obese females
The diagnosis of pes anserine bursitis usually is made on clinical grounds, and further workup is not necessarily indicated. In unusual cases (those that are persistent or suggestive of infection), a further workup can be obtained. In the rare cases where infection appears possible, appropriate laboratory studies may be ordered. If other pathology is suggested, radiography, radionuclide bone scanning, rheumatoid factor measurement, or other rheumatologic testing should be considered.
A diagnostic or therapeutic lidocaine or lidocaine-corticosteroid injection into the area of the pes anserine bursa may help the clinician to determine the contribution of pes anserine bursitis to a patient’s overall knee pathology, as well as possibly alleviate the patient’s symptoms.
Pes anserine bursitis is primarily a self-limiting condition.[3] Patients generally are treated successfully with conservative measures.
Rest, including cutting back or eliminating the offending activities, is essential to therapy. Along with the use of nonsteroidal anti-inflammatory drugs (NSAIDs), it represents first-line treatment.
Physical therapy is beneficial and often is indicated for patients with pes anserine bursitis. Rehabilitative exercise for persons with significant medial knee stress follows general physiatric principles for knee disorders and includes the following:
Stretching and strengthening of the adductor, abductor, and quadriceps groups (especially the last 30° of knee extension using the vastus medialis)
Stretching of the hamstrings
Intrabursal injection of local anesthetics, corticosteroids, or both constitutes a second line of treatment. Surgical therapy is indicated only in very rare cases.
Pes anserinus (“goose’s foot” in Latin) is the anatomic term used to identify the insertion of the conjoined medial knee tendons into the anteromedial proximal tibia; the name derives from the conjoined tendon’s webbed, footlike structure. From anterior to posterior, the pes anserinus comprises the tendons of the sartorius, gracilis, and semitendinosus muscles, each of which is supplied by a different lower-extremity nerve (femoral, obturator, and tibial, respectively). It lies superficial to the distal tibial insertion of the superficial medial collateral ligament (MCL) of the knee.
This bursa serves as a potential space where motion occurs. Its location is generally accepted to be between the conjoined tendons and the superficial MCL (tibial collateral ligament; see the images below). One recent anatomic investigation by ultrasound found variable locations in 170 individuals, most commonly between tendons and tibia and less frequently between MCL and tendons or among the tendons.[4] For various reasons such as injury or contusion, the synovial cells in the lining of the bursa may secrete more fluid, and the bursa may become inflamed and painful.
Another named bursa that is nearby, the musculi sartorii bursa, is smaller and located between the tendon of the sartorius and the conjoined tendons of the gracilis and the semitendinosus muscles; this bursa can communicate with the pes anserinus bursa proper. For the most part, the 2 bursae are regarded collectively as the pes anserinus bursa. In nonsurgical knees, there is usually no communication between these structures and the knee joint itself.
Pes anserine bursitis was initially described in the 1930s as an inflammation of the pes anserinus bursa underlying the conjoined tendons of the gracilis and semitendinosus muscles and separating them from the head of the tibia.[5] It was defined on the basis of observations of this type of bursitis in older adults with arthritis.
The sartorius, gracilis, and semitendinosus muscles are primary flexors of the knee. These 3 muscles also influence internal rotation of the tibia and protect the knee against rotary and valgus stress. Theoretically, bursitis results from stress to this area (such as may result when an obese individual with anatomic deformity from arthritis ascends or descends stairs).
Pathologic studies do not indicate whether symptoms are attributable predominantly to true bursitis, to tendinitis, or to fasciitis at this site.[6] Panniculitis at this location has been described in obese individuals. However, controversy remains regarding the true pathophysiology of the clinical syndrome of pes anserine bursitis/tendinitis, because in many cases where the disorder’s presence is clearly suggested, imaging studies (ultrasonography) fail to demonstrate pathologic findings in the pes anserinus bursa or tendon.
One case of gouty bursitis in the pes anserinus bursa has been described in a patient with known gout, elevated uric acid levels, periarticular MRI findings of pes anserine bursitis, and negative birefringent crystals on ultrasound-guided aspiration of the bursa. However, no contrast study was performed to fully exclude a communication with the articular space.[7]
One case of snapping pes anserine tendons was described associated with bursitis.[8]
The main cause of pes anserine bursitis is underlying tight hamstrings, which are believed to place extra pressure on the bursa, causing a friction bursal irritation.[9] In addition, some patients may have bursal irritation due to a direct blow and thus experience a contusion to this area, as well as resultant inflammation.
Pes anserine bursitis is a common finding in patients who have concurrent Osgood-Schlatter syndrome, suprapatellar plical irritation, or other causes of joint irritation that may cause spasm of the hamstrings (eg, medial meniscal tears or underlying medial compartment or patellofemoral arthritis). Further clarification of the conditions predisposing to pes anserine bursitis is needed, including its mechanical causes and specific pathologic variants. The medical literature suggests that this disorder continues to be underrecognized as a cause of medial knee pain.[10]
Conditions associated with pes anserine bursitis include the following:
Degenerative joint disease of the knee – As many as 75% of patients with such disease may have symptoms of pes anserine bursitis
Obesity (especially in middle-aged women)
Valgus knee deformity, alone or in combination with collateral instability – This appears to increase the risk of pes anserine bursitis or tendinitis[11]
Pes planus (ie, flat foot) – This may predispose patients to pes anserine bursitis and to other problems in the medial knee
Sporting activities that require side-to-side movement or cutting
Local trauma, exostosis, and tendon tightness
Diabetes – Although diabetes was linked to bursitis in 2 studies,[12] the extent to which patients were able to control the diabetes was not documented
A prospective study by Uysal et al found pes anserine bursitis in 20% of patients with symptomatic osteoarthritis and indicated that the diameter and area of pes anserine bursitis correlates positively with the grade of osteoarthritis. The study, which involved 85 patients with primary knee osteoarthritis, also found a greater prevalence of pes anserine bursitis in female and older individuals with osteoarthritis.[13]
Similarly, a study by Kim et al found that in middle-aged and elderly persons examined with radiography and magnetic resonance imaging (MRI), pes anserine bursitis was more common in individuals with knee osteoarthritis than in those without (17.5% vs 2.2%, respectively) and was also more common in persons with knee pain than in those without (14.4% vs 2.5%, respectively).[14]
Another report, by Resorlu et al, indicated that the prevalence of bursitis in the medial compartment of the knee is higher in patients with severe osteoarthritis of the knee or medial meniscus tear. However, no association was found between the presence of chondromalacia patella and the occurrence of medial compartment bursitis.[15]
A retrospective study by Hall et al indicated that in adolescent female athletes, the risk of developing patellofemoral pain is greater in those who specialize in a single sport than in girls who participate in multiple sports but that this does not apply to the development of pes anserine bursitis. According to the study, which involved 546 basketball, soccer, and volleyball players, girls who played just a single sport had a 1.5-fold greater relative risk of patellofemoral pain than did those involved in multiple sports; however, no greater risk between the two groups was found for pes anserine bursitis and several other conditions.[16]
The exact incidence of pes anserine bursitis is unknown, because studies on its prevalence do not exist. It commonly is not recorded as an individual entity by many physicians, who may report the diagnosis simply as anterior knee pain or patellofemoral syndrome. This condition is recognized as occurring in a large number of patients who present to a physician’s office with anterior knee pain.
In a review of 509 magnetic resonance imaging (MRI) scans of symptomatic adult knees suspected of having an internal derangement, evidence of pes anserine bursitis was evident in 2.5%.[17]
Reports suggest that pes anserinus bursitis is far more common in overweight females, owing to the different angulation of the female knee, which puts more pressure on the area where the pes anserinus inserts.[18, 19]
In addition, pes anserinus bursitis is commonly associated with, occurring in 24-34% of patients with type 2 diabetes who report knee pain.[12, 20] A descriptive study of 94 patients with non–insulin-dependent diabetes mellitus identified pes anserine bursitis in 34 subjects, of whom 91% were women and 9% men.[12] Among affected women with diabetes, 62% had the disease bilaterally. None of the control subjects had bursitis without diabetes. Pes anserine bursitis is associated with obesity, and on average, patients with diabetes in this study had greater body mass than the control subjects did.[12] However, the investigators noted that body mass alone did not explain the higher incidence of bursitis among individuals with diabetes.
Pes anserine bursitis is most common in young individuals involved in sporting activities and in obese, middle-aged women. This condition also is common in patients aged 50-80 years who have osteoarthritis of the knees.
In a study of 745 adults aged 50 years or older who had knee pain, the patient group with coexistent nonarticular conditions had significantly higher levels of pain severity and functional limitation than the group without such conditions did.[1] The presence of 1 or more nonarticular conditions accounted for a significant proportion of the variation in Western Ontario and McMaster Universities (WOMAC) physical function scores, even when age, sex, body mass index (BMI), and severity of radiographic osteoarthritis were considered. Of 273 patients with nonarticular conditions, infrapatellar, prepatellar, or pes anserine bursitis was found in 35 patients.
The incidence of pes anserine bursitis appears to be higher among obese, middle-aged women. Among older individuals with arthritis, a slight preponderance of females over males is also noted among patients with pes anserine bursitis arthritis. The prevalence of anserine bursitis in women may result from the broader female pelvis and the greater angulation of women’s legs at the knees, which place additional stresses on these structures.[18, 19]
No racial predilection for pes anserine bursitis is reported in the literature.
By itself, pes anserine bursitis is usually a self-limiting condition. Rest, administration of nonsteroidal anti-inflammatory drugs (NSAIDs), or injection brings about resolution in most cases; surgical intervention is required only rarely. A small risk of infection exists in recalcitrant cases in which the patient may have undergone an injection; however, if this procedure is performed properly under sterile conditions, the risk of infection is small.
Long-term sequelae are few if the individual decides to try to participate in sports or activities and play through the pain. Most athletes return to play sports. In most patients, a 6-8 week stretching and pelvifemoral strengthening exercise program alleviates the symptoms. Chronic arthritic diseases that frequently accompany bursitis obviously persist, but identification and treatment of pes anserine bursitis can significantly reduce pain.
Patients must be educated in the proper means of treatment and, in acute cases, need to allow adequate time for rest. In addition, they need to learn about the importance of proper exercises to rebuild the involved muscles; this is of particular value in helping older individuals with arthritis to avoid disuse atrophy. A home exercise program may be provided by the physical therapist. In athletic settings, patients, trainers, and coaches need to be educated regarding a gradual increase in the patient’s activity level and activity duration according to his or her symptoms.
For patient education resources, see the Arthritis Center, as well as Bursitis, Knee Pain, and Knee Injury.
Pes anserine bursitis can result from acute trauma to the medial knee, athletic overuse, or chronic mechanical and degenerative processes. This condition should not be overlooked when the diagnosis of osteoarthritis of the knee is made, because the 2 are commonly associated.[21] Typical findings in patients with pes anserine bursitis may include the following:
Pain and tenderness over the inner knee – This may occur with arising from a seated position, at night, or with ascending (or, possibly, descending) stairs, though not usually with walking on level surfaces; although patients sometimes point to an area directly over the pes anserine bursa, they may often point to a diffuse region over the medial aspect of the knee; many of these patients also have plical irritation or medial joint compartment pathology (eg, medial meniscal tears or medial compartment arthritis)
Local swelling
Chronic refractory pain in the area during aggravating activities in individuals with arthritis of the knee or in obese females
A history of athletic activity - Generally, susceptible persons are those who are involved in any sport that requires side-to-side movement or cutting; the incidence of pes anserine bursitis is higher among runners and in individuals who play basketball, soccer, and racket sports, in part because of the popularity of these activities
Pes anserine bursitis also has been reported in swimmers; accordingly, the condition occasionally is called breaststroker’s knee, although this term usually refers to medial collateral ligament (MCL) strains. Coexisting MCL pathology may be present among athletes or other individuals with pes anserine bursitis.
The hallmark physical finding in pes anserine bursitis is pain over the proximal medial tibia at the insertion of the conjoined tendons of the pes anserinus, approximately 5-7 cm below the anteromedial joint margin of the knee. At its worst, pes anserine bursal pain is only mild to moderate. Intense pain could suggest a proximal tibial stress fracture.
The pes anserine bursa can be palpated at a point slightly distal to the tibial tubercle and about 3-4 cm medial to it (about 2 fingerbreadths). However, the bursa may not be palpable unless effusion and thickening are present. Palpable crepitus consistent with bursitis occasionally is noted. Pain in this area indicates an underlying inflammation of the pes anserine bursa or a bursitis.
Palpation of this area of the knee is important in a patient who complains of medial knee pain because the examiner needs to determine whether the pain is from joint-line pathology or pes anserine bursal pathology (or both). The 2 may coexist, because pes anserine bursitis can accompany primary knee pathology. Some researchers report pain along the medial joint line, mimicking a meniscal tear. As many as 30% of asymptomatic people may report tenderness when the area of the pes anserine bursa is pressed, so it is important to palpate the contralateral normal knee to verify that the pain on the affected side is more or reproduces their symptoms.
Concurrently with the physical examination, the hamstring-popliteal angle should be assessed to determine the patient’s underlying amount of hamstring tightness. This assessment is made by having the patient’s hip flex to 90° and then passively extending the leg. The angle formed between a perpendicular line to the femoral shaft and the tibial shaft is the hamstring-popliteal angle.
With the sports-related variant or pes anserine bursitis, symptoms may be reproduced by means of resisted internal rotation and resisted flexion of the knee. With the chronic variant in older adults, flexion or extension of the knee usually does not elicit pain. Valgus stress may reproduce the symptoms in athletic individuals, making it hard to distinguish pes anserine bursitis from MCL injuries using this technique alone. Typically, painful tenderness in association with MCL injuries is superior and posterior to the pes anserine bursa.
Noticeable bursal swelling is less frequent among elderly patients with concurrent arthritis. Bursitis is found more frequently on the right side than on the left, and approximately one third of patients have bilateral involvement. If swelling can be traced more proximally along the pes anserine tendons, a formal tendinitis may be present, and a snapping of the pes anserine tendons can occur. Two case reports of large cystic swellings of the bursa that resolved with conservative management have been documented.
An exostosis of the tibia has been described in athletes and may contribute to chronic symptoms.
A study by Colak et al indicated that in rare cases of pes anserine bursitis, intramedullary extension occurs, possibly mimicking a neoplasm clinically and radiologically. The investigators found that out of 542 patients with pes anserine bursitis, eight of them (1.48%) demonstrated bony changes. Radiographic appearance of these changes varied according to the depth of cortical scalloping and intramedullary extension.[22]
In addition to the conditions listed in the differential diagnosis, other problems to be considered include the following:
Medial meniscal tear
Spontaneous osteonecrosis
Tumors
Other bursitis of the knee
Proximal tibia stress/fracture
Saphenous nerve compression
Medial collateral ligament (MCL) sprain can be excluded by means of physical examination or, if necessary, magnetic resonance imaging (MRI).
Medial meniscus injury presents with medial joint line tenderness, knee locking, or catching. The McMurray test is positive with valgus stress and external tibial rotation. In older patients, a degenerative medial meniscus may present with the insidious onset of medial knee pain. Medial synovial plica syndrome (medial plica) can result in point tenderness and palpable clicking over the medial femoral condyle. Parameniscal cysts and dissecting synovial cyst (from another location) can cause swelling in the area.
Medial ligament syndrome is a poorly defined syndrome described in rheumatology literature as causing pain at the site of insertion of the MCL. Valgus stress exacerbates pain, and the patient may have pain behaviors. The etiology is unknown, but, in some cases, an inflammatory arthropathy, such as ankylosing spondylitis, is present. Medial ligament syndrome is treated with rest, heat, and a small corticosteroid injection.
Medial tibial condyle bone marrow edema associated with soft tissue edema surrounding the MCL on MRI has been reported to result in a painful syndrome of medial tibial crest friction, possibly related to the angle of the crest.[23] This is not to be confused with medial tibial stress syndrome, "shin splints," which is pain in the mid-to-distal tibia.
Osteonecrosis (death of subchondral bone due to an unknown cause) of the femur may present with sudden, severe medial compartment knee pain that is constant (day and night). Bone scanning shows increased uptake in the femoral condyle.
Tumors in the region can include villonodular synovitis, osteochondromatosis, and synovial sarcoma.[24, 25, 26] Synovial hemangioma, meniscal cyst, xanthomas, and ganglion cyst also may occur here.
Of the more than 150 bursae in the body, at least 12 of them are found in each knee, including the suprapatellar, prepatellar, deep infrapatellar, adventitious cutaneous, gastrocnemius, semimembranosus, sartorius, anserine, and MCL bursae, as well as 3 lateral knee bursae located adjacent to the fibular collateral ligament and the popliteus tendon (laterally). Knee pain may be the consequence of inflammation of any of these bursae.
The MCL bursa is located at the anterior border of the MCL. It may be palpable during knee flexion as a small, tender, rounded nodule moving into the leading edge of the MCL. Pain can be elicited by palpating the bursa or by briskly extending the knee from a position of 90° flexion. Pes anserine tendonitis may exist exclusively or in conjunction with bursitis. So-called snapping tendinitis of the semitendinosus tendon is usually thought of as distinct from pes anserine bursitis, but some authorities classify it as the same inflammatory disorder.
Semimembranosus tendinitis can occur with running or cutting activities. This condition is characterized by swelling over the posteromedial aspect of the knee and by tenderness with resisted flexion or valgus strain. An insertional enthesopathy of the semimembranosus has also been described.
Stress fractures of the proximal medial tibia may produce pain in the area of the pes anserine bursa.
Nerve injuries causing medial joint pain include trauma to the infrapatellar branch of the saphenous nerve and injury during knee surgery, especially arthroscopy. Pain can be reproduced with the Tinel sign. One case report documents distal tibial pain from entrapment of the saphenous nerve caused by pes anserine bursitis.[27] Medial knee pain associated with back pain also could represent an L3-L4 radiculopathy. Electrodiagnostic tests, such as electromyography (EMG) and nerve conduction velocity tests, may be useful.
Osgood-Schlatter Disease
The diagnosis of pes anserine bursitis usually is made on clinical grounds, and further workup is not necessarily indicated. In unusual cases (those that are persistent or suggestive of infection), a further workup can be obtained. In the rare cases where infection appears possible, appropriate laboratory studies may be ordered. If other pathology is suggested, radiography, radionuclide bone scanning, rheumatoid factor measurement, or other rheumatologic testing should be considered.
A diagnostic or therapeutic lidocaine or lidocaine-corticosteroid injection into the area of the pes anserine bursa may help the clinician to determine the contribution of pes anserine bursitis to a patient’s overall knee pathology, as well as possibly alleviate the patient’s symptoms.
Infections of the pes anserine bursa are very rare and occur primarily in immunocompromised patients. These patients typically have a localized area of warmth, pain, and swelling. In such cases, a standard laboratory workup for infection is indicated, including determination of the erythrocyte sedimentation rate (ESR), a complete blood count (CBC) with differential, and measurement of the C-reactive protein (CRP) level.
If the bursa or joint is aspirated for this or other reasons, analysis of the fluid may include a cell count, assessment of fluid appearance, Gram staining, culture, and polarized light microscopy.
As a rule, radiography of the knee is not indicated for bursitis. However, plain radiographs (standing anteroposterior [AP] and lateral views) can be useful for ruling out a proximal tibial stress fracture, as well as for helping to diagnose concurrent pathology, such as medial compartment arthritis, osteochondroma, or osteochondritis dissecans, which could contribute to tight hamstrings and pes anserine bursal irritation. Arthritis may be observed in older adults. In rare cases, young, athletic patients have an exostosis in the metaphyseal area.
Ultrasonography can facilitate the diagnosis of pes anserine bursitis.[28, 29] Large, cystic bursal swellings have been identified by means of ultrasonography and computed tomography (CT). However, published reports suggest that in most suspected cases, ultrasonographic findings are lacking.[30] This lack of ultrasonographic findings has led some to question the frequency of pes anserine bursitis and its accepted pathophysiology.
In one study, only 3 of 29 patients with suspected pes anserinus tendinobursitis were found to have tendinitis on ultrasonographic images when compared with the uninvolved extremity or healthy controls.[30] In a study of patients with type 2 diabetes mellitus, 4 out of 14 patients who were clinically diagnosed with pes anserine tendinobursitis syndrome were found to have ultrasonographically apparent morphologic changes in the pes anserine tendons.[20]
Magnetic resonance imaging (MRI) is the preferred imaging technique for confirming the diagnosis of pes anserine bursitis and differentiating it from concurrent pathology of the medial compartment.[31, 32] On MRI, the pes anserine bursa is observed between the pes anserinus (ie, the insertion of the conjoined gracilis, semitendinosus, and sartorius tendons into the anteromedial proximal tibia) and the upper tibial metaphysis.
The appearance of pes anserine bursitis on MRI is characterized by increased signal intensity and fluid formation around the area of the pes anserinus bursa. A collection of fluid with low signal intensity is observed on T1-weighted images, and a homogenous increase in signal intensity is observed on T2-weighted images. Fluid-filled anserine bursae have been reported with a prevalence of 5% in asymptomatic knees; consequently, the diagnosis of pes anserine bursitis cannot be based solely on MRI findings.[31]
Limited axial and sagittal T2-weighted or T2 gradient-echo sequences usually are adequate for diagnosis. More extensive imaging with additional planes may be required to exclude other clinically relevant possibilities. Axial images are particularly helpful for differentiating fluid in the pes anserine bursa from other medial fluid collections, such as Baker and meniscal cysts, bone cysts, and fluid in the semimembranosus bursa.[33] MRI also is helpful for ruling out a proximal tibial stress fracture.[31]
At least 1 case of chronic pes anserine bursitis manifested as a solid, inflammatory synovial mass. One report describes tibial erosion under bursitis. Pigmented villonodular synovitis with hemosiderin deposits can occur focally in the bursae.
Pes anserine bursitis is primarily a self-limiting condition.[3] Patients generally are treated successfully with conservative measures and typically should receive outpatient physical therapy. For preventive purposes, every athlete should participate in a regular stretching program for the hamstring tendons.
Intrabursal injection of local anesthetics, corticosteroids, or both constitutes a second line of treatment. Surgical therapy is indicated only in very rare cases.
In patients whose symptoms last more than several months, consideration may be given to referring the patient to a specialist to confirm the diagnosis and rule out other potential causes of the patient’s pain (eg, proximal tibial plateau fracture). Cases that do not respond to a program of activity modification and exercise may be referred to a specialty-trained, sports medicine physician, primary care physician, or orthopedic surgeon for evaluation.
Rest, including cutting back or eliminating the offending activities, is essential to treatment. Along with the use of nonsteroidal anti-inflammatory drugs (NSAIDs), it represents first-line treatment.
Physical therapy is beneficial and often is indicated for patients with pes anserine bursitis. Rehabilitative exercise for persons with significant medial knee stress follows general physiatric principles for knee disorders and includes the following:
Stretching and strengthening of the adductor, abductor, and quadriceps groups (especially the last 30° of knee extension using the vastus medialis)
Stretching of the hamstrings
Thus, patients with pes anserine bursitis need to work on both a hamstring stretching program and a concurrent closed-chain quadriceps and pelvifemoral strengthening program. Such programs can usually be taught to the patient by an athletic trainer or physical therapist. Patients should understand that to gain the maximum benefit from this program, they must stretch their hamstrings frequently during the day, sometimes hourly. The quadriceps strengthening program is recommended in most patients because of other concurrent pathology in the knee.
A regular program of hamstring stretching and quadriceps strengthening usually results in alleviation of the pain from pes anserine bursitis in approximately 6-8 weeks. Addition of a nonsteroidal anti-inflammatory drug (NSAID) may help to alleviate some of the pain at this time. In addition, and an ice massage may help to reduce inflammation. Ice in foam cups can be applied and rubbed directly on the patient’s skin (ice massage) for up to 10 minutes at a time; other forms of cryotherapy (eg, cold packs) also may be used.
During the rehabilitation program, the patient should incorporate the following measures:
Continue with activity modification as necessary
Begin a gradual resumption of activities
Continue alternative training for cardiovascular fitness
After regaining full, pain-free motion with good isometric strength, work on improving strength and endurance
Advise older patients and those with chronic pain to avoid muscle atrophy from disuse. Address obesity in cases in which it is a contributing factor.
A small cushion placed between the thighs before sleeping is useful in managing medial knee bursitis.
If resective surgery is performed, the knee remains in extension or slight flexion within an immobilizer for 1-2 weeks after surgery. Pursue active range-of-motion (AROM) exercises until 3 weeks after surgery, then begin progressive resistive exercises (PREs).
Other appropriate means of and ideas for treating pes anserine bursitis include the following:
Ultrasound – This is reportedly effective in reducing inflammation associated with pes anserine bursitis
Electrical stimulation – This has been used in other forms of bursitis, although its use has not been documented specifically in pes anserine bursitis
A study by Khosrawi et al indicated that pes anserine bursitis can be effectively treated with extracorporeal shock wave therapy (ESWT). The visual analog scale and the McGill Pain Questionnaire total pain index were used to assess mean pain scores before and immediately after therapy, as well as 8 weeks after the treatment’s conclusion. The investigators found the follow-up scores to be significantly lower in patients who received ESWT than they were in patients who received sham ESWT.[34]
A study by Homayouni et al reported that in patients with pes anserine tendinobursitis, pain and swelling can be better reduced with kinesiotaping than with a combination of the nonsteroidal anti-inflammatory drug (NSAID) naproxen and physical therapy. The study compared kinesiotaping with treatment consisting of 250 mg of naproxen three times per day for 10 days plus 10 daily physical therapy sessions, with pain and swelling measured with the visual analog scale (VAS) and ultrasonography, respectively.[35]
Intrabursal injection of local anesthetics, corticosteroids, or both represents a second-line treatment option. It should be considered only for refractory cases that have not responded to physical therapy, rest, ice, and NSAIDs. A study found no difference in short-term pain relief between 3-5 mL of 1% lidocaine with methylprednisolone and the same amount of lidocaine without the corticosteroid.
Injection can be directed to the point of maximal tenderness. Care should be taken to avoid injecting any of the 3 tendons converging at the pes anserinus; injection within the tendons themselves can weaken these structures and intensify the patient’s pain. Ultrasound guidance has demonstrated effectiveness in cadaveric studies, increasing accuracy from 17% (unguided) to 92%.[36]
Occasionally, an area 0.5-1 cm higher than the tendons is injected in order to include the medial collateral ligament (MCL) bursa, which also may be a pain generator. Injection of the knee joint itself may be beneficial in recalcitrant cases.
Generally, use a 22-gauge or 23-gauge needle to inject 1-3 mL of 1% lidocaine and corticosteroid (20-40 mg of triamcinolone, 20-40 mg of methylprednisolone, or 6 mg of betamethasone). If infection—which is rarer here than in the bursae of the anterior knee—is suggested, use a larger, 19- or 20-gauge needle and a 20-30 mL syringe for aspiration. Relief is usually immediate but may not be complete.
Repeated lidocaine injections or the use of corticosteroids may result in longer-lasting relief (from 1 to several months). No more than 3 injections should be used over a 1-year period, with intervals of at least 1 month between injections. It should be kept in mind, however, that patients who do not respond to the initial injection rarely respond to repeat treatments.[18] Patients who do not respond to initial injection rarely respond to repeated bursal injections.
A study by Sarifakioglu et al indicated that physical therapy and corticosteroid injection are similarly effective in the treatment of pes anserine tendinobursitis. In the study, 60 patients with a combination of knee osteoarthritis and pes anserine tendinobursitis were divided into physical therapy and corticosteroid injection treatment groups, with significant improvement seen in functional capacity and pain scores in both groups after 8 weeks.[37]
Surgical management of pes anserine bursitis is very rarely warranted. Surgery is usually indicated when an immunocompromised patient has a localized infection that does not resolve with standard antibiotic treatment. Surgical decompression of the bursa may be performed in such cases.
Clinically, pes anserine bursitis can mimic distal anteromedial knee disorders or internal derangement of the knee, sometimes leading to unnecessary surgery. In an investigation of 509 magnetic resonance imaging (MRI) studies done on patients thought to have an internal knee derangement, the prevalence of pes anserine bursitis was found to be 2.5%.[17]
In cases of disability, such as those causing 6-8 weeks of limitation in athletes, some surgeons advocate resection, especially if mature exostosis is present and causing irritation. The operation includes excision of the bursa and any bony exostosis.
In patients with generalized anterior knee pain, activity modification may be necessary to allow the joint to quiet down and to allow the hamstring tightness to resolve. In most patients, this modification involves minimizing the use of stairs, climbing, or other activities that cause irritation of the joint.
Athletes and active patients may return to play or activities as their symptoms permit. In more severe cases, restrictions on activities may be necessary. Athletes who play contact sports may benefit from the use of a protective pad over the affected area.
In general, medications are not frequently used to treat pes anserine bursitis. In cases where pharmacologic therapy may be warranted to help alleviate symptoms, the addition of an over-the-counter or prescribed anti-inflammatory medication, such as a nonsteroidal anti-inflammatory drug (NSAID), may be indicated. In addition, injection of a local anesthetic, with or without a corticosteroid, may be helpful.
NSAIDs have analgesic, anti-inflammatory, and antipyretic activities. Their mechanism of action is not known, but they may inhibit cyclooxygenase (COX) activity and prostaglandin synthesis. Other mechanisms may exist as well, such as inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation, and various cell-membrane functions.
Although increased cost can be a negative factor, the incidence of costly and potentially fatal gastrointestinal (GI) bleeding is clearly lower with COX-2 inhibitors than with traditional NSAIDs. Ongoing analysis of the cost of preventing GI bleeding will further define the populations that will find COX-2 inhibitors the most beneficial.
Anesthetic (local) and corticosteroid combinations may be used. Local anesthetics stabilize neuronal membranes and prevent the initiation and transmission of nerve impulses, thereby producing local anesthesia. Corticosteroids have anti-inflammatory properties and cause profound and varied metabolic effects; in addition, they modify the body’s immune response to diverse stimuli. This compounded medication consists of 0.5 mL of betamethasone and 2.0 mL of 1% lidocaine without epinephrine.
Ibuprofen is the drug of choice for patients with mild to moderate pain. It inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.
Naproxen is used for relief of mild to moderate pain; inhibits inflammatory reactions and pain by decreasing the activity of cyclooxygenase, thereby decreasing prostaglandin synthesis.
Indomethacin is rapidly absorbed; metabolism occurs in the liver by demethylation, deacetylation, and glucuronide conjugation. It inhibits prostaglandin synthesis.
Ketoprofen is used for relief of mild-to-moderate pain and inflammation. Small dosages are initially indicated in small and elderly patients and in those with renal or liver disease. Doses greater than 75 mg do not yield increased therapeutic effects. Administer high doses with caution, and closely observe the patient for response.
Celecoxib primarily inhibits COX-2. COX-2 is considered an inducible isoenzyme, induced during pain and inflammatory stimuli. Inhibition of COX-1 may contribute to NSAID GI toxicity. At therapeutic concentrations, COX-1 isoenzyme is not inhibited; thus, GI toxicity may be decreased. Seek the lowest effective dose of celecoxib for each patient.
Corticosteroids have anti-inflammatory properties and cause profound and varied metabolic effects. They modify the body’s immune response to diverse stimuli.
Triamcinolone decreases inflammation by suppressing migration of polymorphonuclear leukocytes (PMNs) and reversing capillary permeability.
Methylprednisolone decreases inflammation by suppressing migration of PMNs and reversing increased capillary permeability.
Betamethasone decreases inflammation by suppressing migration of PMNs and reversing increased capillary permeability.
Overview
What is pes anserine bursitis?
What is the anatomy of the pes anserinus relevant to pes anserine bursitis?
What is the pathophysiology of pes anserine bursitis?
What causes pes anserine bursitis?
Which conditions are associated with pes anserine bursitis?
What are risk factors for pes anserine bursitis?
What is the prevalence of pes anserine bursitis in the US?
How does the prevalence of pes anserine bursitis vary by age?
Which patient groups are at highest risk for pes anserine bursitis?
What is the prognosis of pes anserine bursitis?
What information about pes anserine bursitis should patients be given?
Presentation
What are the signs and symptoms of pes anserine bursitis?
Which physical findings are characteristic of pes anserine bursitis?
DDX
Which conditions should be included in the differential diagnoses of pes anserine bursitis?
How is medial collateral ligament sprain differentiated from pes anserine bursitis?
How is medial meniscus injury differentiated from pes anserine bursitis?
How is medial ligament syndrome differentiated from pes anserine bursitis?
How is medial tibial condyle bone marrow edema differentiated from pes anserine bursitis?
Which tumors should be included in the differential diagnoses of pes anserine bursitis?
Which bursae of the knee may cause pes anserine bursitis?
How is semimembranosus tendinitis differentiated from pes anserine bursitis?
How are stress fractures differentiated from pes anserine bursitis?
How are nerve injuries differentiated from pes anserine bursitis?
What are the differential diagnoses for Pes Anserine Bursitis?
Workup
How is pes anserine bursitis diagnosed?
What is the role of lab studies in the workup of pes anserine bursitis?
What is the role of radiography in the workup of pes anserine bursitis?
What is the role of ultrasonography in the workup of pes anserine bursitis?
What is the role of MRI in the workup of pes anserine bursitis?
Treatment
What are the treatment options for pes anserine bursitis?
What is included in the conservative management of pes anserine bursitis?
What is included in a rehabilitation program for the treatment of pes anserine bursitis?
What is included in rehabilitative therapy following restrictive surgery for pes anserine bursitis?
What is the role of ultrasound and electrical stimulation in the treatment of pes anserine bursitis?
What is the efficacy of kinesiotaping in the treatments of pes anserine bursitis?
What is the role of surgical decompression and resection in the management of pes anserine bursitis?
Which activity modifications are used in the treatment of pes anserine bursitis?
Medications
What is the role of drug treatment for pes anserine bursitis?