Prevalence of triceps tendon tears on MRI of the elbow and clinical correlation.

OBJECTIVE: Triceps tendon injuries are reported to be very rare. To our knowledge, there have been no studies describing its prevalence or injury patterns on MR imaging. The purpose of this retrospective study was to determine the prevalence and patterns of triceps injuries based on a large series of consecutive MR examinations. Clinical correlation was obtained. MATERIALS AND METHODS: From 801 consecutive elbow MR examinations over a 15-year period, 28 patients with 30 triceps tendon injuries were identified and graded as partial tendon tear and complete tendon tear. The patients' medical records were reviewed to determine age, gender, cause of tears, and management. RESULTS: The prevalence of triceps tendon injuries was 3.8%. There were 5 women and 23 men with partial or complete tears (mean age: 46.6 years; range: 2.7 to 75.1 years). The most common injury was partial tear, found in 18 patients. There were 10 patients with 12 complete tears (2 had re-torn following surgical repair). A tear was suspected in 12 out 28 (43%) patients prior to the MRI. The most common presenting symptom was pain. The most common cause was athletic injury (8 patients [29%], including weightlifting [2 patients]). Tendon tear was found to be a complication of infection in 6 patients, and in 3 patients the tears were a complication of steroid use. Thirteen tendon tears were surgically repaired (8 of these were complete tears). CONCLUSIONS: Triceps tendon injury is not as rare as commonly reported and may often be clinically underdiagnosed.

Imaging findings, prevalence and outcome of de novo and secondary malignant fibrous histiocytoma of bone.

OBJECTIVE: To evaluate the radiographic and magnetic resonance (MR) imaging features of primary and secondary malignant fibrous histiocytoma in bone and determine the demographics, prevalence and outcome of patients with this tumor. MATERIALS AND METHODS: A retrospective search of files from two institutions identified 28 patients with malignant fibrous histiocytoma (MFH) of bone. Microscope slides were reviewed to confirm diagnosis and identify any pre-existing lesions. Medical records were reviewed with respect to patients' demographic characteristics and outcomes. RESULTS: Radiographic features demonstrated an aggressive osteolytic lesion with a permeative pattern of bone destruction. Periosteal reaction was seen in three of 13 lesions. T1-weighted images (T1WIs) demonstrated signal intensity iso- to slightly hyperintense to muscle. T2-weighted images (T2WIs) demonstrated mildly higher signal intensity than that of muscle. The 5-year survival rate was 53%. The tumor arose secondarily in pre-existing lesions in 43% of patients. Metastases occurred in 46% of patients during the course of the disease, with pulmonary and osseous metastases being the most common. CONCLUSION: Secondary MFH of bone was slightly less common than primary MFH and had a prognosis similar to that of primary MFH of bone. MR imaging showed variable and somewhat unusual low to intermediate T2 signal characteristics for a radiographically malignant osteolytic lesion.

Bilateral congenital absence of the long head of the biceps tendon.

Absence of the long head of the biceps tendon is a rare anomaly particularly when it occurs bilaterally. We present the magnetic resonance and arthroscopy findings in a patient with bilateral congenital absence of the long head of the biceps who presented with bilateral shoulder pain. Identification of a shallow or absent intertubercular groove may aid in differentiating congenital absence of the long head of the biceps from a traumatic tendon rupture.

Third head of the gastrocnemius: an MR imaging study based on 1,039 consecutive knee examinations.

OBJECTIVE: The objectives of this study were to determine the frequency of a third head of the gastrocnemius and to describe the course, morphology, and insertion of the third head as seen on the basis of routine magnetic resonance (MR) imaging of the knee. MATERIALS AND METHODS: This study was a prospective study of 1,039 consecutive knee MR examinations which were performed for symptoms of pain not associated with claudication. The examinations were performed between September 2004 and January 2005 and were evaluated for the presence of an anomalous third head of the gastrocnemius and to determine its origin and course. Examinations were performed on a variety of magnets ranging from 0.2 to 1.5 T. RESULTS: Of the 1,039 knees, 20 (1.9%) demonstrated an anomalous third head of the gastrocnemius which was seen arising near the midline of the posterior distal femur, between the mid and medial aspect, and joining the medial aspect of the lateral head of the gastrocnemius. The size of the third head varied from a thin threadlike muscle to a rather bulky muscle. In all of these patients, the third head coursed lateral to the popliteal vessels, and none coursed between the vessels. One additional case of a third head of the gastrocnemius was seen which joined the medial head of the gastrocnemius. CONCLUSION: A third head of the gastrocnemius joining the lateral head is not an uncommon variant, seen in 1.9% of knee MR examinations. Most are not associated with vascular symptoms.