perspectives on pain ADDRESSING PATIENT NEEDS Anserine bursitis An under-diagnosed, easily treatable cause of knee pain he anserine bursa was initially called the no-name-no-fame BY SUZAN M. ATTAR, MD tbursa. The term anserine bur- sitis presently in use was coined by Moshcowitz in 1937, when he first pelvic area, which results in angu- lateral ligament injury or from pes described the condition.1 lation at the knee joint, putting anserine tendonitis. Certain provo- The anserine bursa is located more pressure on the pes anserine cative manoeuvres, however, may medially, 6 cm below the joint line attachment. Secondary causes in- help: between the attachment of the med- clude medial compartment osteo- • tenderness that extends from ial collateral ligament and the con- arthritis of the knee, obesity, direct the anserine bursal area to the joined tendon (see Figures 1 and 2). trauma, abnormal gait, tight ham- joint line is more likely due to Pes anserinus means “goose’s foot” strings and, less commonly, over- inflammation or injury of the and is the anatomic location of the use injury, as in athletics.4 medial collateral ligament conjoined tendons formed by gracilis, • the supine valgus stress test, sartorius and semitendinosus mus- Clinical symptoms which is used to determine the cles in the knee.2 This article will pro- Pain is localized to a well-defined integrity of the medial collateral vide an overview, including the clinical area on the medial knee region over ligament, should not aggravate presentation and management. the upper tibia. Patients often point the pain of anserine bursitis to the spot with one finger. The pain • prone resisted knee flexion (ham- Presentation can be bilateral and nocturnal. It’s string contraction) may reproduce There are several bursae surround- aggravated by climbing stairs, getting the pain of anserine bursitis ing the knee, three of which com- out of a chair and bending the knee. It • in difficult cases, a local anesthe- monly become inflamed and cause may lead to the sensation of the knee tic block in the bursa can be used knee pain: “giving way.” to differentiate the symptoms of • the anserine bursa, located on the bursitis from other etiologies. inner side of the knee Exam and investigations Relief of pain with the injection • the prepatellar bursa, in front of On physical examination, upon pal- is diagnostic of anserine bursitis. the patella pation, tenderness is elicited about X-rays of the knee aren’t neces- • the two infrapatellar bursae, un- 5-6 cm below the medial joint line sary to make the diagnosis. Plain derneath the patella at the level of the tibial tubercle. films of the knee, though, includ- Anserine bursitis is used loosely There’s no evidence of joint effu- ing the sunrise view, are recom- to describe pain over the medial as- sion, but there may be some slight mended to assess for secondary pect of the upper tibia. This could swelling at the insertion of the med- osteoarthritis. arise from the medial collateral ial hamstring muscles. Infections of the pes anserine ligament, the anserine bursa and It’s often impossible to separate bursa are very rare and occur in the pes anserinus insertion.3 anserine bursitis from medial col- immunocompromised patients. A Idiopathic bursitis occurs mainly Suzan M. Attar, MBBS, FRCPC, ABIM is a clinical rheumatology fellow in the in women because of their broad Division of Rheumatology at the University of Ottawa. PARKHURST EXCHANGE 23 JULY 2005 perspectives on pain ADDRESSING PATIENT NEEDS • restriction of activities — elimi- peated after 6-8 weeks. About 70% nation of squatting and crossing of patients injected experience sig- the legs, and avoidance of direct nificant pain relief.5 pes anserinus pressure on the bursa (using a muscles pillow between the knees at night) Surgery • application of ice packs for 15- Surgery is indicated if two consec- 6 cm below the medial joint line 30 minutes every 4-6 hours to utive aspirations and injections fail at the level of the tibial tubercule tibial tubercule relieve pain to eliminate swelling. Still, bursec- • knee protection with elastic ban- tomy is rarely required — less than tibial bone dage to relieve the swelling 1% of cases. • physiotherapy for hamstring stret- Figure 1: Cross-section of the thigh ching and strengthening exer- Summary showing the anatomic location of the anserine bursa. cises for the quadriceps muscles Anserine bursitis is an under-diag- • anti-inflammatory therapy, e.g. nosed cause of knee pain. It can be non-steroidal anti-inflammatory ascertained by point tenderness and drugs, oral or topical, for 6-8 weeks. a negative valgus stress test, and is All these modalities are evidence easily treated with anti-inflammatory level 1C, i.e. no randomized controlled drugs or a cortisone injection. PE trial demonstrated efficacy. References: 6 cm below the medial Persistent symptoms 1. Handy JR. Anserine bursitis: a brief joint line, at the level of review. South Med J 1997;90(4):376-7. tibial tubercule Most of the patients respond to 2. West SG. Rheumatology Secrets. 2nd Ed. conservative treatment. Failure to Denver, CO. Hanley & Belfus, 2002: 445, 452. do so, however, may require a ste- 3. Hochberg M et al (eds). Rheumatology, 3rd Ed. Baltimore, MA. C.V. Mosby, 2003: Figure 2: Anterior view of the roid injection — 0.5 mL of a local Aspiration and injection of the joint and knee, showing the location of anesthetic plus 40 mg of methyl- periarticular tissue, p. 242. 4. Fireman HH. Don’t forget anserine bursitis. anserine bursa. prednisolone — inserted 6 cm below CMAJ 2001;165(10):1300. the medial joint line at the level of 5. Gnanadesigan N, Smith RL. Knee pain: standard workup for infection is the tibial tubercle.3 Injection after- osteoarthritis or anserine bursitis? J Am Med Dir Assoc 2003;4(3):164-6. required at that point. care is critical for success. The in- 6. Hill CL et al. Periarticular lesions detected dividual should be advised to rest on magnetic resonance imaging: prevalence in knees with and without symptoms. Treatment the joint for three days by avoiding Arthritis Rheum 2003;48(10):2836-44. The goals of treatment are to re- direct pressure, squatting and re- 7. Calmbach WL, Hutchens M. Evaluation of duce the inflammation and correct petitive bending. Ice packs should patients presenting with knee pain: Part II. Differential diagnosis. Review. the underlying cause. be applied for 15-30 minutes every Am Fam Physician 2003;68(5):917-22. 4-6 hours. Physiotherapy can be 8. Taunton JE, Wilkinson M. Rheumatology: 14. Diagnosis and management of anterior Conservative therapy resumed by day 4. If symptoms knee pain. Review. This consists of the following: persist, the injection could be re- CMAJ 2001;164(11): 1595-601. 24 PARKHURST EXCHANGE JULY 2005.