Nontraumatic knee pain: A diagnostic & treatment guide

Treatment. A wide range of options, from eccentric training—eg, 3 sets of 15 repetitions performed twice a day for 12 weeks—and physical therapy to platelet-rich plasma (PRP) injections, sclerosing injections, and surgery, are available for the treatment of patellar tendinopathy.^13-15 While no specific data have proven the superiority of any one therapy, expert consensus recommends eccentric exercise as initial therapy, performed for 12 weeks.^14,15

Three weeks of platelet-rich plasma injections helped 75% of patients with patellar tendinopathy return to their pre-symptom activity level within 90 days. It’s also interesting to note that a recently published study showed that 3 weekly PRP injections helped 75% of patients—all of whom failed to respond to 4 months of eccentric therapy—return to their pre-symptom activity level within 90 days.¹⁶ Corticosteroid injections should not be used to treat patellar tendinopathy due to the risk of tendon rupture.¹⁵ Orthopedic referral for surgical intervention should be considered for patients who fail to respond after 3 to 6 months of conservative therapy.¹⁴

Lateral knee pain

Iliotibial band tendinopathy


Iliotibial band syndrome (ITBS) is a common source of lateral knee pain, particularly in runners, cyclists, and endurance athletes.^17-19,36,37 The exact pathophysiology behind this diagnosis is debatable, but the most accepted etiology is inflammation generated from micro trauma to the soft tissues with inadequate healing time, resulting in persistent inflammation. ITBS is often associated with excessive overall running mileage, a sudden increase in mileage, or an abrupt change in training.^18,37

Patients with ITBS often complain of persistent nontraumatic knee pain that worsens with repetitive knee flexion. Diagnosis. Patients often complain of persistent nontraumatic lateral knee pain that worsens with repetitive knee flexion (eg, running or cycling).^17-19,37 A physical exam will often reveal pain over the lateral femoral condyle and a positive Noble’s test (FIGURE 1). A positive Ober’s test (FIGURE 2) is suggestive of ITBS, as well. The sensitivity and specificity of these tests are not well established, but in patients performing repetitive knee flexion activities with subjective lateral knee pain, pain over the lateral femoral condyle and a positive Ober’s and/or Noble’s test suggest an ITBS diagnosis.¹⁸ Imaging is not indicated initially, but MRI should be used in refractory cases to rule out other etiologies.^17,19

Treatment. First-line therapy for ITBS is conservative,^17-19,36,37 often involving a combination of techniques such as refraining from the activity that triggers the pain, NSAIDs, activity modification to reduce the strain over the ITB, myofascial release via foam rollers, and physical therapy focused on stretching the iliotibial band, tensor fasciae latae, and gluteus medius while strengthening the gluteus medius and core muscles.¹⁷ No single program has been shown to be better than another.

Corticosteroid injections are second-line therapy and have been shown to improve pain compared with placebo up to 2 weeks post injection.^17,19 When symptoms persist for more than 6 months despite conservative treatment, surgical intervention may be indicated.^18,19 Patients who experience temporary pain relief with corticosteroid injections often respond best to surgery.³⁶

Medial knee pain

Medial plica syndrome

Because of its anatomic location, the medial plica—which can be palpated in up to 84% of the population²⁰—is susceptible to impingement by the medial femoral condyle or the patellofemoral joint. Trauma with repetitive knee movement leads to inflammation and thickening of the plica, resulting in medial plica syndrome.^20,38 Initial inflammation may be triggered by blunt trauma, a sudden increase in activity, or transient synovitis.²²

Diagnosis. Medial plica syndrome is a challenging diagnosis. Patients generally have nonspecific complaints of aching medial knee pain, locking, and catching similar to complaints of a medial meniscal injury.²⁰

A mediopatellar plica test was more accurate than an MRI in diagnosing medial plica syndrome, according to a recent systematic review. Evaluation should include the mediopatellar plica test, which is performed with the patient lying supine with the knee fully extended. Pressure is placed over the inferomedial patellofemoral joint, creating an impingement of the medial plica between the finger and the medial femoral condyle. Elimination or marked diminishing of pain with knee flexion to 90° is considered a positive test.²¹

A recent systematic review found this test to be more diagnostically accurate than an MRI (sensitivity of the test is 90% and specificity is 89%, vs 77% and 58%, respectively, for MRI) for detection of medial plica syndrome. Ultrasound is almost as accurate, with a sensitivity of 90% and specificity of 83%.³⁹

Treatment of medial plica syndrome centers on physiotherapy and quadriceps strengthening,²⁰ augmented with NSAIDs. Intra-articular corticosteroid injections are considered second-line treatment.^20,22 An orthopedics referral is indicated to consider arthroscopic plica removal for refractory cases.^20,22