A Runner With Knee Pain

PATIENT PROFILE:

For 4 weeks, a 23-year-old runner has had a painful burning sensation about 1 inch above andlateral to the left knee cap. Occasionally, the pain radiates to her hip and 1 inch down the lateralside of her leg.The patient recently increased the length of her runs to prepare for a half-marathon.Initially, the pain began about 15 minutes into a run and subsided after she stopped. Now, itlimits her ability to run and persists after she stops. The pain increases when she runs downhill;however, sprinting does not exacerbate it. She started riding a bike as an alternativeexercise, but this activity worsened the pain. No other movements exacerbate it. The paindoes not limit her ability to sit with her kneeflexed for long periods, and she has notexperienced locking ("catching"), grinding,or buckling of the knee.The patient is healthy, and there is nohistory of direct trauma to the knee. She isnot obese and does not wear restrictive ortight clothing.

WHAT IS YOUR PRESUMPTIVE DIAGNOSISAT THIS POINT?

A.

Lateral meniscus tear.

B.

Patellar femoral tracking syndrome(chondromalacia).

C.

Iliotibial band syndrome.

D.

Meralgia paresthetica.

E.

Lateral collateral ligament tear.THE CONSULTANT'S CHOICE
Patellar femoral tracking syndrome (B) is a possibility,but it is usually associated with a different history.Typically, the pain is in the center of the knee. Affectedpatients usually complain of buckling and grinding,and they have difficulty keeping the knee flexed forprolonged periods.

¹

This patient has none of theseproblems.Meralgia paresthetica (D) is caused by compressionof the lateral femoral cutaneous nerve as it comesunder the inguinal ligament near the anterior superioriliac spine and runs over the sartorious muscle. Whenthis nerve is compressed, a burning pain on the lateralside of the thigh may result. Restrictive clothing thatis tight around the waist is the usual cause of thecompression, and the pain is aggravated by extendingthe back (bending backwards). This patient's painoccasionally radiates to the lateral thigh, but this is notits primary location. Moreover, she does not wear tightclothing.Meniscal tears (A) are associated with a history oftrauma (specifically, a twisting injury) and a historyof the knee's catching or buckling. None of these arepresent here.Lateral collateral ligament tears (E) are associatedwith lateral knee pain; however, these injuries arerare, are caused by direct trauma, and are associatedwith buckling. This patient has no history of trauma orbuckling.Rather, the history here suggests

iliotibial bandsyndrome

(ITBS) (choice C)--the most common overusesyndrome in distance runners. Sharp, burning lateralknee pain that may radiate up into the lateral thighor down to the Gerdy tubercle (easily palpated on thetibia just lateral to the distal portion of the patellar tendon)is the usual presentation. Runners often describe aspecific, reproducible setting in which their symptomsstart.

Pathophysiology of ITBS.

The iliotibial band (ITB)is a dense fascia on the lateral aspect of the knee and hip.It originates proximally from the tensor fasciae latae, thegluteus maximus, and the gluteus medius (an importantpoint to remember in rehabilitation). In the distal thigh,the ITB passes over the lateral femoral epicondyle and attachesto the Gerdy tubercle on the anterolateral aspectof the proximal tibia (

Figure 1

). Aponeurotic connectionsto the patella and the vastus lateralis stabilize the patellaagainst medially directed forces. The function of the ITBdepends on the position of the knee. At less than 20 degreesof flexion, the ITB acts as an extensor, and at morethan 30 degrees of flexion, it assists with flexion.The pain of ITBS results from friction that occurswhen the ITB crosses over the lateral femoral epicondyle,which happens when the knee is flexed between20 and 30 degrees. This range of angles is knownas the friction, or impingement, zone. With excessiveflexion and extension of the knee in the impingementzone, inflammation and ITBS result.Patients with ITBS typically note more pain withdownhill running because the knee is flexed more frequentlyin the impingement zone during this activity.Sprinting does not cause pain because when an athleteruns fast, the knee is flexed more often at anglesgreater than 30 degrees and not in the impingementzone. Riding a bicycle can also produce or aggravateITBS (as it did in this patient) because the knee isflexed for a considerable time in the impingement zone.

Physical findings in ITBS.

Note any swelling or atrophy,especially of the vastus medialis muscle. Atrophyof the vastus medialis is common in many knee injuries.Check the range of motion of the hip and knee, andnote any limitation on the injured side compared withthe normal side. These observations can be used to followtreatment progress. Look for weakness of the hipabductor (common in ITBS) and tenderness over thelateral femoral epicondyle (see

Figure 1

) when theknee is flexed more than 30 degrees. The latter findingis usually seen in affected patients.

WHICH OF THE FOLLOWINGTESTS IS MOST LIKELYTO YIELD A POSITIVE RESULTIN A PATIENT WITH ITBS?

A.

Patellar push test.

B.

Lachman test.

C.

Noble compression test.

D.

Knee varus stress test.

E.

McMurray test.THE CONSULTANT'S CHOICE
The Noble compression test(choice

C

) is used to diagnoseITBS. To perform this test, applypressure to the lateral femoral epicondylewhile the knee is fully extended(

Figure 2

), then slowly flexthe knee. The result is positive ifthe patient reports pain at 30 degreesof knee flexion (see

Figure2

) and/or the examiner palpates arubbing or snapping sensation asthe ITB passes over the lateralfemoral epicondyle.Perform the other tests listedabove to rule out other causes ofknee pain. The patellar push test (A)helps diagnose patellar femoraltracking syndrome. The Lachmantest (B) can identify an anteriorcruciate ligament injury. The varusstress test (D) stresses the lateralarea of the knee and assists in thediagnosis of lateral collateral ligamentinjuries. The McMurray test(E) helps diagnose injuries to the lateral and medialmenisci.The Ober test (

Figure 3

) can also help diagnoseITBS. This test assesses ITB tightness. Have the patientlie on the unaffected side with the lower hip and kneeboth flexed to 120 degrees. With the involved kneeflexed to 90 degrees, help the patient to abduct and thenhyperextend the hip on the same side. After this, let thetop leg drop. If the ITB is tight, it will prevent the extremityfrom dropping below an imaginary horizontalline passing midway between the 2 hips (see

Figure 3

).Tight ITB is commonly seen in ITBS.The results of a Noble test and an Ober test arepositive in this patient. Her hip abductors are weak, andan examination of her gait reveals that she pronateswith her left foot. Results of all other tests--for ligamentousstability and patellar femoral tracking syndrome--are negative.

WHAT WOULD YOU DO NOW?

A.

Obtain a radiograph of the knee.

B.

Obtain an MRI scan of the knee.

C.

Have the patient start a rehabilitationprogram.

D.

Prescribe crutches, and advise the patientto avoid weight bearing for 2 weeks.THE CONSULTANT'S CHOICE
The diagnosis is clear, and no further evaluation isneeded. Radiographs (A) are normal in ITBS. MRI (B)is used only to rule out other causes when a patient hasnot responded to conservative measures after 6 monthsand surgery is being considered.Most patients with ITBS respond to nonoperativemeasures. Recommend activity modification (walking insteadof running or cycling for 1 to 2 weeks), exercisesto strengthen weak hip abductors and hamstring muscles,and stretches to increase ITB flexibility (C). Also,prescribe a short course (7 to 10 days) of NSAIDs and,when appropriate (as in this case), orthotics to correctexcessive foot pronation. Neither the use of crutchesnor the avoidance of weight bearing (D) is necessary; infact, these prolong disability.After patients have avoided running and cycling fora short period, they can slowly start to run or bike again.Symptoms and conditioning guide this process. Havepatients continue to stretch the ITB and strengthen themedial abductors after they resume normal activity.Symptoms usually abate by 3 to 6 weeks. Consider acorticosteroid injection into the underlying bursa (

Figure4

) in refractory cases.The identification and correction of training errorsenhance treatment and prevent future injuries. Thismay involve decreasing mileage, altering stride length,avoiding hills, or periodically changing direction whenrunning on a sloped surface. Cyclistsmay need to change their seat heightor foot position.Surgery may be consideredafter at least 6 months of nonoperativemanagement. Following arthroscopyto exclude intra-articularpathology, a portion of the ITB isexcised.After 1 week of walking shortdistances and not running, the patientin this case gradually started torun again. She began to use orthotics,and she now increases thedistance she runs slowly rather thanabruptly. She still plans to competein a half-marathon, but at a laterdate.