Femoral tunnel placement during anterior cruciate ligament reconstruction: an in vivo imaging analysis comparing transtibial and 2-incision tibial tunnel-independent techniques.

BACKGROUND: Recent studies have questioned the ability of the transtibial technique to place the anterior cruciate ligament graft within the footprint of the anterior cruciate ligament on the femur. There are limited data directly comparing the abilities of transtibial and tibial tunnel-independent techniques to place the graft anatomically at the femoral attachment site of the anterior cruciate ligament in patients. HYPOTHESIS: Because placement with the tibial tunnel-independent technique is unconstrained by the tibial tunnel, it would allow for more anatomic tunnel placement compared with the transtibial technique. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: High-resolution, multiplanar magnetic resonance imaging and advanced 3-dimensional modeling techniques were used to measure in vivo femoral tunnel placement in 8 patients with the transtibial technique and 8 patients with a tibial tunnel-independent technique. Femoral tunnel placement in 3 dimensions was measured relative to the center of the native anterior cruciate ligament attachment on the intact contralateral knee. RESULTS: The tibial tunnel-independent technique placed the graft closer to the center of the native anterior cruciate ligament attachment compared with the transtibial technique. The transtibial technique placed the tunnel center an average of 9 mm from the center of the anterior cruciate ligament attachment, compared with 3 mm for the tibial tunnel-independent technique. The transtibial technique resulted in a more anterior and superior placement of the tunnel compared with the tibial tunnel- independent technique. CONCLUSION: The tibial tunnel-independent technique allowed for more anatomic femoral tunnel placement compared with the transtibial technique.

Observer variability in assessing articular surface displacement in acetabular fractures using a standardized measurement technique.

The objective of this study was to determine the inter- and intraobserver reliability of plain films as compared with CT scans in quantitatively measuring articular displacement in acetabular fractures utilizing a standardized measurement technique. Three independent reviewers compared the standardized measurement technique to direct measurement of the articular displacement. Weighted kappa statistics were performed to assess the inter- and intraobserver agreement. The standardized method of measurement showed slightly better inter- (0.24) and intraobserver (0.36) reliability for measuring articular displacement, as compared to direct measurement (0.12 and 0.22). Measurements using CT scans showed higher inter- (0.3) and intraobserver (0.43) reliability, when compared to plain radiographs (0.27 and 0.36). Measurements performed on fracture patterns which did not include a posterior wall component had higher inter- (0.41) and intraobserver (0.44) reliability, when compared to patterns with posterior wall fractures (0.12 and 0.22). Based on these results, it was concluded that the use of the standardized method of measurement, as described by Borrelli etal., was not superior to direct measurement of articular displacement.

MRI appearance of surgically proven abnormal accessory anterior-inferior tibiofibular ligament (Bassett's ligament).

OBJECTIVE: A thickened accessory anterior-inferior tibiofibular ligament (Bassett's ligament) of the ankle can be a cause of ankle impingement. Its imaging appearance is not well described. The purpose of this study was to determine if the ligament could be identified on magnetic resonance imaging (MRI), to determine associated abnormalities, and to determine if MRI could be used to differentiate normal from abnormal. MATERIALS AND METHODS: Eighteen patients with a preoperative ankle MRI and an abnormal Bassett's ligament reported at surgery were found retrospectively. A separate cohort of 18 patients was selected as a control population. The presence of Bassett's ligament and its thickness were noted. The integrity and appearance of the lateral ankle ligaments, talar dome cartilage, and anterolateral gutter were also noted. RESULTS: In 34 of the 36 cases (94%), Bassett's ligament was identified on MRI. The ligament was seen in all three imaging planes and most frequently in the axial plane. The mean thickness of the ligament in the surgically abnormal cases was 2.37 mm, compared with 1.87 mm in the control with a p value=0.015 (t test). Nine of the 18 abnormal cases (50%) had talar dome cartilage lesions as a result of contact with the ligament at surgery, with only 3 cases of high-grade defects seen on MRI. Fourteen of the 18 abnormal cases (78%) had of synovitis or scarring in the lateral gutter at surgery, with only 5 cases with scarring seen on MRI. The anterior-inferior tibiofibular ligament was abnormal or torn in 8 of the 18 abnormal cases (44%) by MRI and confirmed in only 3 cases at surgery. DISCUSSION: Bassett's ligament can be routinely identified on MRI and was significantly thicker in patients who had it resected at surgery. An abnormal Bassett's ligament is often present in the setting of a normal anterior-inferior tibiofibular ligament. The cartilage abnormalities and synovitis associated with an abnormal Bassett's ligament are poorly detected by conventional MRI.

Quadrilateral space syndrome: incidence of imaging findings in a population referred for MRI of the shoulder.

OBJECTIVE: The purpose of this study was to determine the incidence of MRI findings suggesting quadrilateral space syndrome in a population referred for shoulder MRI. CONCLUSION: Focal teres minor atrophy or abnormal signal suggesting quadrilateral space syndrome is an uncommon, although not rare, finding on MRI of the shoulder in our referral population and is rarely an isolated abnormality.

MR imaging of infrapatellar plica injury.

OBJECTIVE: Injury to the infrapatellar plica (ligamentum mucosum) has not been previously described in the radiology literature to our knowledge. This article shows the MR imaging appearance of injury to the infrapatellar plica. CONCLUSION: Injury to the infrapatellar plica is uncommon but should be considered as a potential source of knee pain, especially if no other evidence indicates internal derangement. MR imaging can reveal a typical appearance for infrapatellar plica injury.

Utility of fine-needle aspiration in the diagnosis of primary osteosarcoma.

Fine-needle aspiration (FNA) is a reliable, safe, and cost-effective procedure with a well-established role in the diagnosis of various solid tissue neoplasms. The role of FNA in the diagnosis of primary bone tumors, including osteosarcoma (OGS), is controversial and has yet to be established. We reviewed our experience with the use of FNA as a diagnostic technique over the past 8 yr at our institution. Diagnosis was conclusive in 26 (65%) of 40 patients, 18 of whom went to neoadjuvant therapy and/or resection based solely on the FNA interpretation of either "high grade sarcoma" or "osteosarcoma." Of the remaining 14 (25%) patients, 12 had inconclusive diagnosis and two (5%) were false-negatives. An inconclusive diagnosis was most likely to be an inadequate or paucicellular aspirate, seen in six (15%) patients. An additional six patients had variants of osteosarcoma (four chondroid, one "giant cell rich," one parosteal) that made definitive diagnosis impossible. The two that were incorrectly classified were diagnosed as fracture callus and plasmacytoma. FNA is an accurate and cost-effective tool for the initial diagnosis of primary osteosarcoma with a sensitivity of 65% and accuracy of 95%. Inconclusive diagnoses are likely to be due to insufficient sample cellularity or the presence of OGS variant. In our experience, FNA is sufficient to provide the diagnosis of OGS prior to definitive treatment when interpreted in conjunction with imaging studies and clinical findings. In those cases where FNA fails to yield a diagnostic sample, a traditional biopsy can be performed.