To determine the optimum foot position and imaging plane at magnetic resonance (MR) imaging of each ankle ligament, 10 cadaver ankles were dissected to visualize the orientation, precise attachment sites, and relationships of each ligament. Then eight cadaver ankles were studied with MR imaging and were cryosectioned in the optimum imaging planes. The ankles of 12 healthy volunteers were imaged to ensure consistency in identifying the normal ligaments. With the foot taped into full dorsiflexion of 10 degrees-20 degrees, axial imaging provided optimum views of the anterior, posterior, and inferior tibiofibular ligaments and of the anterior and posterior fibulotalar ligaments and provided an overview of the deltoid ligament. Coronal images provided full-length views of the tibiospring, tibiocalcaneal, and posterior tibiotalar parts of the deltoid ligament. With the foot taped into full plantar flexion of 40 degrees-50 degrees, axial imaging optimized visualization of the fibulocalcaneal ligament and of the tibionavicular and anterior tibiotalar parts of the deltoid ligament. Sagittal images provided the best full-length views of the spring ligament.

The magnetic resonance (MR) images of 14 wrists of patients with carpal tunnel syndrome (CTS) were studied. Four general findings visible regardless of the cause of CTS included swelling of the median nerve, best evaluated at the level of the pisiform bone; flattening of the median nerve, most reliably judged at the hamate level; palmar bowing of the flexor retinaculum, best visualized at the level of the hamate bone; and increased signal intensity of the median nerve on T2-weighted images. Findings related to cause were tendon sheath edema in traumatic tenosynovitis, synovial hypertrophy in rheumatoid tenosynovitis, a ganglion cyst, and excessive amount of fat within the carpal tunnel, a persistent median artery, and a large adductor pollicis muscle. Knowledge of these findings may permit more rational choice of treatment. In four cases in which symptoms persisted after surgery, findings valuable in explaining or predicting the failure included incomplete incision of the flexor retinaculum, excessive fat within the carpal tunnel, persistent neuritis of the median nerve, and development of neuromas.

Radiological findings in 75 cases of aneurysmal bone cyst were analyzed. Sixty-five per cent were primary or simple and 35% were secondary, the aneurysmal bone cyst being combined with other osseous lesions. A primary aneurysmal bone cyst can be diagnosed with a high degree of certainty, but only 20% of secondary forms had the radiological appearance of aneurysmal bone cyst; in the other 80% the associated lesion dominated the radiological picture, particularly when it was malignant. In the secondary form a small biopsy specimen may show the features of aneurysmal bone cyst only; without radiological assistance a concomitant malignant lesion may be missed. Therefore, there must be close collaboration between the radiologist and and the pathologist.

Thirteen patients with clinically diagnosed sprained ankles underwent magnetic resonance (MR) imaging. Five of these cases are presented to illustrate the potential of MR imaging to enable identification of both primary and associated ligament injury sites, grading of the severity of the injuries, and visualization of the associated findings of tendon sheath and joint effusion. The appropriate combination of foot position and imaging plane is essential to achieve full-length visualization of each ligament. Two patients demonstrated findings compatible with total gross disruption of the anterior fibulotalar ligament; two, with injury to the fibulocalcaneal ligament with effusion of the overlying peroneus tendon sheath; and one, with thinning, lengthening, and fibrotic changes involving the anterior fibulotalar ligament. MR imaging can provide a noninvasive means to evaluate the site and severity of ankle ligament injuries (a) in acute ankle injuries that demonstrate significant instability, (b) in stable acute injuries involving athletes or litigation, or (c) in patients with repeated injuries or instability in whom surgery is contemplated.

Twenty-one joints with stable (n = 9) or loose (n = 12) osteochondritis dissecans (OCD) lesions were examined in 15 subjects with plain radiography, three-phase bone scintigraphy, and magnetic resonance (MR) imaging. The lesion size and the thickness of the sclerotic margin as measured on plain radiographs were good parameters for predicting loosening. However, bone scintigraphy was more sensitive and specific in determining the mechanical stability of OCD lesions. MR imaging permitted direct visualization of loosening and fragment displacement; the latter permits differentiation of in situ loosening from a grossly unstable lesion. The noninvasive nature of bone scintigraphy and MR imaging makes them potentially preferable diagnostic modalities to arthrography for evaluating the mechanical status of OCD lesions.