MR imaging findings of medial tibial crest friction

Friction Syndromes of the Knee

The knee is a complex joint with many fascial and ligamentous interactions. The movement in multiple planes makes the knee a prime site for friction syndromes, especially in active individuals. The most common friction syndrome is the iliotibial band friction syndrome. This occurs commonly in runners and cyclists and can be diagnosed clinically in a patient with lateral knee pain during activity. The anterior fat pads of the knee can also be the site of friction syndromes, most often in the Hoffa fat pad. Edema here can be located in the superolateral aspect of the fat pad when associated with patellar abnormalities, or diffusely when impingement is due to other causes. Edema of the quadriceps or prefemoral fat pad may also cause anterior knee pain and may be diagnosed with magnetic resonance imaging. The posteromedial friction syndrome and medial tibial crest syndrome are rare causes of medial knee pain highly active individuals.

A Case of Medial Tibial Crest Friction Syndrome: A Rare Cause of Medial Knee Pain

Knee pain is among the most common problems in active patients, with common causes of medial knee pain including meniscal injury, osteoarthritis, medial collateral ligament (MCL) injury, and pes anserine bursopathy/distal hamstring tendinopathy. Some cases of medial knee pain are refractory to standard treatment options and may be caused by rare pathology. We present a case of medial knee pain secondary to medial tibial crest friction syndrome (MTCFS) in a 22-year-old male training for a sprint triathlon after rapidly increasing his training program. Magnetic resonance imaging revealed bone marrow and soft-tissue edema about the MTC deep to the MCL consistent with MTCFS. The patient failed a period of relative rest and activity modification, but improved with corticosteroid injection deep to the MCL in the location of his symptoms. This case highlights a potential management option for MTCFS, a disorder previously described only in radiologic literature.

Overstride-Induced Medial Knee Desmopathy: An Exploration Case Series

Nine runners with varied experience but similar running-gait forms presented with the insidious and progressive onset of medial knee pain. Functional tightness of the semimembranosus (SM) tendon appeared to be a concomitant factor in the pain presentation of these patients. When evaluating atraumatic medial knee pain in runners, clinicians must consider bone stress injuries and atypical conditions. A functionally tight SM may induce pain and desmopathy of the medial collateral ligament through direct fiber entanglement or cause entrapment of infrapatellar branches of the saphenous nerve or both. Relieving SM tension resulted in short-term pain reduction while eliminating the overstride during the running gait over the long term appeared to prevent recurrence.

[Bone marrow edema syndrome from the perspective of appraisers and insurance clerks]

Various diseases or groups of diseases can trigger bone marrow edema (BME). The task of the appraiser is to work out the role of a diagnosed BME in the context of the causality based on liability; however, the inconsistent ICD 10 coding of the BME complex also poses a problem, especially for medically untrained insurance clerks. The coding of the BME as a fracture provided by the coding guidelines poses a problem when assessing reserves for damage settlement. Based on the etiology of BME an algorithm is presented that should make it easier for the expert as well as for the insurance clerk in the case of liability and also for the private accident insurance to classify the diagnosis of BME in the case.

Magnetic resonance imaging of impingement and friction syndromes around the knee

The knee is a complex joint with its function dependent on a combination of osseous and soft tissue structures. Alteration in the relationship of these tissues, due to either acute or chronic repetitive injury with possible underlying congenital predisposing factors, can result in impingement between the structures resulting in pain, particularly on activity. The purpose of this article is to provide a comprehensive review of the MRI features of various impingement syndromes around the knee.

Ultrasound-guided injection for the diagnosis and treatment of posteromedial knee friction syndrome

OBJECTIVE

To describe an ultrasound guided injection technique for diagnosing and treating posteromedial knee friction syndrome, which occurs between the sartorius/gracilis tendons and medial femoral condyle (MFC).

MATERIALS AND METHODS

Our study was IRB-approved and HIPAA-compliant. We identified patients via a retrospective review of medical records and MRI with posteromedial knee pain and isolated edema between MFC and sartorius/gracilis tendons and no evidence for meniscal tear, ruptured Baker's cyst or degenerative joint disease. Patients were referred for an ultrasound-guided procedure to inject anesthetic and corticosteroid at the site of edema. Procedures were evaluated for technical success, which was defined as satisfactory identification of the injection site and adequate delivery of medication. Follow-up was available up to 8 weeks after the procedure to determine the response and any potential complications.

RESULTS

Fourteen subjects with MRI and symptoms of posteromedial knee friction syndrome underwent 14 injections. Technical success was achieved in all procedures, with no complications. At 8 weeks' follow-up, 92% of patients had symptom improvement. VAS before and 8 weeks after the procedure changed from 5.2 ± 2.7 to 0.9 ± 2.1 (p = 0.0002), respectively.

CONCLUSION

Ultrasound-guided injection of edema between the MFC and sartorius/gracilis tendons supports the diagnosis of a posteromedial knee friction syndrome and successfully treats its associated symptoms.

Effect of bone-soft tissue friction on ultrasound axial shear strain elastography

Bone-soft tissue friction is an important factor affecting several musculoskeletal disorders, frictional syndromes and the ability of a bone fracture to heal. However, this parameter is difficult to determine using non-invasive imaging modalities, especially in clinical settings. Ultrasound axial shear strain elastography is a non-invasive imaging modality that has been used in the recent past to estimate the bonding between different tissue layers. As most elastography methods, axial shear strain elastography is primarily used in soft tissues. More recently, this technique has been proposed to assess the bone-soft tissue interface. In this paper, we investigate the effect of a variation in bone-soft tissue friction coefficient in the resulting axial shear strain elastograms. Finite element poroelastic models of bone specimens exhibiting different bone-soft tissue friction coefficients were created and mechanically analyzed. These models were then imported to an ultrasound elastography simulation module to assess the presence of axial shear strain patterns. In vitro experiments were performed to corroborate selected simulation results. The results of this study show that the normalized axial shear strain estimated at the bone-soft tissue interface is statistically correlated to the bone-soft tissue coefficient of friction. This information may prove useful to better interpret ultrasound elastography results obtained in bone-related applications and, possibly, monitor bone healing.

Posteromedial knee friction syndrome: an entity with medial knee pain and edema between the femoral condyle, sartorius and gracilis

OBJECTIVE

To describe MRI features of an entity consisting of medial knee pain and edema between the posteromedial femoral condyle (PMFC), sartorius and/or gracilis tendons and determine whether reduced tendon-bone distances may account for these findings.

METHODS

We retrospectively identified MRI cases of edema between the PMFC, sartorius and/or gracilis tendons (25 subjects, 26 knees). Two musculoskeletal radiologists independently graded edema and measured the sartorius- and gracilis-PMFC distances and knee flexion angle. Age- and gender-matched subjects with normal knee MRIs (27 subjects, 27 knees) served as controls for measurements. Statistical analyses compared abnormal to control subjects.

RESULTS

Sartorius-PMFC and gracilis-PMFC spaces were narrower in abnormal compared to control subjects (1.6 ± 1.0 vs. 2.1 ± 1.2 mm, P = 0.04; 2.3 ± 2.0 vs. 4.6 ± 3.0 mm, P = 0.002, respectively). The knee flexion angle was similar between groups (P > 0.05). In subjects with clinical information, medial knee pain was the main complaint in 58 % (15/26) of abnormal subjects, with 42 % (11/26) having clinical suspicion of medial meniscal tear. Edema between the PMFC, sartorius and/or gracilis was mild in 54 % (14/26), moderate in 35 % (9/26) and severe in 12 % (3/26), and it was most frequent deep to both the sartorius and gracilis (50 %, 13/26).

CONCLUSIONS

Edema between the PMFC, sartorius and/or gracilis tendons identified on knee MRI may be associated with medial knee pain and may represent a friction syndrome.