Coronal oblique imaging of the knee: can it increase radiologists' confidence in diagnosing posterior root meniscal tears?

AIM: To investigate the utility of the coronal oblique sequence in the interrogation of posterior root meniscal lesions. MATERIALS AND METHODS: Following international review board approval, 62 consecutive knee arthroscopy cases were referred to the musculoskeletal (MSK) radiologists from the same orthopaedic surgeon for imaging/surgical correlation of the posterior meniscal roots. Of 62 cases, 45 lateral and 46 medial menisci met the inclusion criteria. Imaging evaluation was performed with standard magnetic resonance imaging (MRI) sequences, including a coronal oblique proton density sequence. Two blinded fellowship-trained MSK radiologists independently evaluated the menisci on standard sequences indicating whether a tear was identified and then specifying a confidence score using a scale of 1-3 on each study interpreted. Immediately thereafter, the coronal oblique sequence was evaluated using the same method. Statistics were performed on meniscal lesions involving the posterior horn/root junction or isolated root tears comparing confidence scores. RESULTS: Reader A identified nine posterior horn/root junction tears and 14 isolated root tears. Following the addition of the coronal oblique sequence, confidence scores increased in three of 14 (21.4%) isolated root tears. All three final reads were concordant with arthroscopy. Reader B identified 10 posterior horn/root junction tears and 19 isolated root tears. The confidence score increased in six cases: five of 19 (26.3%) isolated root tears and one of 10 (10%) posterior horn/root junction tears. All six final reads were concordant with arthroscopy. Kappa coefficients indicated near perfect agreement. CONCLUSION: The coronal oblique sequence increased reader confidence in nearly 24% of the posterior root cases identified in this series.

The posterior transtriceps approach for elbow arthrography: a forgotten technique?

OBJECTIVE: To evaluate the technical feasibility of performing elbow MR arthrography via a posterior approach through the triceps. MATERIALS AND METHODS: The images of 19 patients with elbow MR arthrography via a posterior transtriceps approach were retrospectively studied. The injections were performed by four musculoskeletal radiologists, using fluoroscopic guidance and a 22- or 25-gauge needle. The fluoroscopic and subsequent MR images were reviewed by two musculoskeletal radiologists and evaluated for adequacy of joint capsular distention, degree and location of contrast leakage, and presence of gas bubbles. RESULTS: The injection was diagnostic in all 19 patients, with a sufficient amount of contrast agent seen in the elbow joint. No significant contrast leakage occurred in 12 patients who received injections of 8 cc or less of contrast agent, but moderate contrast leakage occurred in 6/7 patients who received injections of greater than 8 cc. Contrast leakage generally occurred within the triceps myotendinous junction. No gas bubbles were identified in the injected joints. CONCLUSION: Patients often present for MR arthrography of the elbow with medial or lateral elbow pain. Contrast leakage during a radiocapitellar approach may complicate evaluation of the lateral collateral ligament or the common extensor tendon origin. Transtriceps MR arthrography offers an alternative to the more commonly used radiocapitellar approach. With injected volumes not exceeding 8 cc, the risk of significant contrast leakage is small. An advantage of the transtriceps injection is that contrast leakage through the posterior needle tract does not interfere with evaluation of the lateral structures.

The effect of recombinant human osteogenic protein-1 on allograft incorporation.

We used a canine intercalary bone defect model to determine the effects of recombinant human osteogenic protein 1 (rhOP-1) on allograft incorporation. The allograft was treated with an implant made up of rhOP-1 and type I collagen or with type I collagen alone. Radiographic analysis showed an increased volume of periosteal callus in both test groups compared with the control group at weeks 4, 6, 8 and 10. Mechanical testing after 12 weeks revealed increased maximal torque and stiffness in the rhOP-1 treated groups compared with the control group. These results indicate a benefit from the use of an rhOP-1 implant in the healing of bone allografts. The effect was independent of the position of the implant. There may be a beneficial clinical application for this treatment.