Does anterior cruciate ligament reconstruction restore normal knee kinematics?: A prospective MRI analysis over two years.

This prospective study used magnetic resonance imaging to record sagittal plane tibiofemoral kinematics before and after anterior cruciate ligament reconstruction using autologous hamstring graft. Twenty patients with anterior cruciate ligament injuries, performed a closed-chain leg-press while relaxed and against a 150 N load. The tibiofemoral contact patterns between 0 degrees to 90 degrees of knee flexion were recorded by magnetic resonance scans. All measurements were performed pre-operatively and repeated at 12 weeks and two years. Following reconstruction there was a mean passive anterior laxity of 2.1 mm (sd 2.3), as measured using a KT 1000 arthrometer, and the mean Cincinnati score was 90 (sd 11) of 100. Pre-operatively, the medial and lateral contact patterns of the injured knees were located posteriorly on the tibial plateau compared with the healthy contralateral knees (p=0.014), but were no longer different at 12 weeks (p=0.117) or two years postoperatively (p=0.909). However, both reconstructed and healthy contralateral knees showed altered kinematics over time. At two years, the contact pattern showed less posterior translation of the lateral femoral condyle during flexion (p<0.01).

Focal myositis.

Focal myositis is a rare, benign focal inflammation of muscle. The lesion often presents as a mass that may be mistaken for a soft tissue sarcoma. This report describes the MRI and histopathological features of a case and illustrates how the diagnosis may be suspected on the basis of the MR findings.

The use of MRI in the diagnosis of benign and malignant bone and soft tissue tumours.

Two hundred and thirty four suspected primary bone and soft tissue tumours were investigated using plain films and MRI. The MR appearance of 200 of these tumours was assessed with respect to the intensity of the lesion, the homogeneity of the tumour, the presence or absence of a capsule or lobulation, whether the tumour was whorled or not and whether it contained either fluid or blood. Apart from benign lipomas and some malignant myxoid liposarcomas, however, it seemed virtually impossible to tell one tumour from another and in many cases to differentiate a benign lesion from a malignant tumour using MRI alone. We recommend that the workup of a suspected soft tissue tumour should be initially by MR scanning and that the workup of a suspected malignant bone tumour should be plain films followed by an MRI scan.

Radiologic case study. MRI in the diagnosis of synovial disease.

Fourteen patients with various synovial diseases were imaged using conventional radiographic techniques and MRI. We had five patients with synovial tumors, including two each with PVNS and synovial osteochondromatosis. We had five patients with infections and four patients with various other forms of arthritis. Although MRI was found to be a useful means to visualize the synovium, the findings were nonspecific except in the case of PVNS.

Peripheral (extracranial) nerve tumors: correlation of MR imaging and histologic findings.

Magnetic resonance (MR) images of 16 peripheral nerve tumors (14 patients) were correlated with histopathologic appearance. Thirteen patients had surgically proved neuro-fibromatosis. There were 10 neurofibromas, four schwannomas, and two neurofibrosarcomas. Seven of the 10 neurofibromas showed a target pattern of increased peripheral signal intensity and decreased central signal intensity on T2-weighted images. This pattern appeared to correspond to a distinctive zonal histologic appearance that was found only in the neurofibromas. This pattern was not seen on MR images of the other peripheral tumors.

Bursitis in association with solitary osteochondromas presenting as mass lesions.

Three patients with solitary osteochondromas which were increasing in size have been recently examined. Plain films were available on all patients; two patients had MR studies, and two had CT scans. In all three cases, malignant transformation of the osteochondroma was suspected from the cross-sectional imaging studies, but pathologic examination proved that these patients all had bursa formation without any evidence of malignancy. The incidence of this rare complication of solitary osteochondroma is discussed. Ultrasound is also recommended for the evaluation of enlarging solitary osteochondromas.