Pretibial cyst formation after anterior cruciate ligament surgery with soft tissue autografts.

Four cases of subcutaneous pretibial ganglion, with direct communication to the tibial tunnel after autologous reconstruction of the anterior cruciate ligament (ACL) with hamstrings or iliotibial band, are reported. Tibial graft fixation was with a staple in three cases, and with a screw and soft tissue washer in one. The average time to ganglion development was 44 months, and all occurred more than 2 years after ACL surgery. At the time of cyst development, no patient had subjective or objective knee instability. No patient had evidence of tibial tunnel enlargement. All ganglion communicated with the tibial tunnel. This communication was shown with magnetic resonance imaging in two cases, which showed the origin at the joint. Three patients elected to have the ganglion removed; in each of these there was a direct communication with the tibial tunnel. Additionally, hardware was removed in all cases, and local autologous bone grafting of the tibial tunnel aperture was done in two. Minimum follow-up after surgical excision was 2 years, without evidence of recurrence.

Posterolateral rotatory instability of the elbow: usefulness of MR imaging in diagnosis.

PURPOSE: To evaluate the efficacy of magnetic resonance (MR) imaging in the assessment of the normal and abnormal ulnar band of the lateral collateral ligament for diagnosis of posterolateral rotatory instability. MATERIALS AND METHODS: In nine symptomatic patients and nine asymptomatic subjects, MR imaging was performed with three-dimensional gradient-recalled and fast spin-echo sequences. The nine patients had clinical symptoms suggestive of subtle elbow instability. RESULTS: The components of the lateral collateral ligament were identified; tears of the ulnar band were noted in all symptomatic patients. The anterior fibers of the lateral collateral ligament, including the annular ligament, were intact. All symptomatic patients subsequently underwent surgical exploration and reconstruction. Positive clinical findings were demonstrated at examination performed while the patients were under anesthesia. All tears of the ulnar band were confirmed. CONCLUSION: With use of appropriate pulse sequences, MR imaging is an effective tool in the preoperative, noninvasive diagnosis of posterolateral rotatory instability.

Labral injuries: accuracy of detection with unenhanced MR imaging of the shoulder.

PURPOSE: To prospectively assess the accuracy of unenhanced magnetic resonance (MR) imaging in the detection and localization of labral injuries. MATERIALS AND METHODS: One hundred three patients with clinically suspected shoulder injuries were prospectively examined with unenhanced MR imaging. A combination of gradient-echo and high-resolution fast-spin-echo axial pulse sequences were used. Surgical correlation was obtained in all patients. RESULTS: At surgery, 37 torn anterior, 36 torn superior, and 19 torn posterior labral were identified. The sensitivity for detection of these tears with MR imaging was 100%, 86%, and 74%, respectively; the specificity was 95%, 100%, and 95%, respectively. Overall, unenhanced MR imaging was 95% accurate in the detection of labral injuries. CONCLUSION: With appropriate pulse sequences, unenhanced MR imaging of the shoulder is an accurate technique for the detection and localization of labral injuries.