Patellofemoral replacement: the third compartment.

Isolated patellofemoral arthritis is a common condition and there are varying opinions on the most effective treatments. Non-operative and operative treatments have failed to demonstrate effective long-term treatment for those in an advanced stage of the condition. Newer designs and increased technology in patellofemoral replacement (PFR) have produced more consistent outcomes. This has led to a renewed enthusiasm for this procedure. Newer PFR prostheses have addressed the patellar maltracking issues plaguing some of the older designs. Short-term results with contemporary prostheses and new technology are described here.

MRI of meniscal bucket-handle tears.

OBJECTIVE: A meniscal bucket-handle tear is a tear with an attached fragment displaced from the meniscus of the knee joint. Low sensitivity of MRI for detection of bucket-handle tears (64% as compared with arthroscopy) has been reported previously. We report increased sensitivity for detecting bucket-handle tears with the use of coronal short tau inversion recovery (STIR) images. DESIGN AND PATIENTS: Three hundred and twenty-seven patients who had MRI of the knee between October 1994 and December 1996 and subsequently underwent arthroscopy were included in the study. We prospectively and retrospectively reviewed the MR examinations of the 30 patients with arthroscopically proven bucket-handle tears. Each of two observers examined each scan for the three traditional findings of bucket-handle tears: a double posterior cruciate ligament sign, a flipped meniscus sign and/or a fragment in the intercondylar notch. We also assessed STIR images in the coronal plane through the menisci looking for an area of increased signal within either meniscus with a displaced meniscal fragment. RESULTS: By using four criteria for diagnosis of meniscal bucket-handle tears, our overall sensitivity compared with arthroscopy was 93% (28 of 30 meniscal bucket-handle tears seen at arthroscopy were detected by MRI). The meniscal fragment was well visualized in all 28 cases on coronal STIR images. The double posterior cruciate ligament sign was seen in 8 of 30 cases, the flipped meniscus was seen in 10 of 30 cases and a fragment in the intercondylar notch was seen in 18 of 30 cases. CONCLUSION: By using four criteria for diagnosis of bucket-handle tears, overall diagnostic sensitivity of MRI compared with arthroscopy increased from the previously reported 64% to 93%. Coronal STIR images are useful for detecting small meniscal bucket-handle tears.

Usefulness of MR imaging in the detection of talar dome injuries.

OBJECTIVE: Patients with significant ankle injuries often have normal findings on conventional radiographs despite severe ligament, tendon, and bone injuries. MR imaging was used to assess the incidence of talar dome injuries in patients who had failed conservative therapy after ankle trauma. SUBJECTS AND METHODS: MR images were obtained in 30 patients with persistent ankle pain 6 weeks after an injury. All patients had normal findings on conventional radiographs. Patients with clinical symptoms suggesting ligamentous instability were excluded from the study. Simplified MR sequences using coronal T1-weighted and short inversion time inversion recovery images were used. Total scan time for each patient was 11 min. RESULTS: On MR imaging, 17 (57%) of 30 patients had injuries at the talar dome despite normal findings on conventional radiographs. Early detection resulted in cessation of physical therapy and casting of the ankle for 4 weeks. Ten of the patients with abnormalities on MR imaging underwent follow-up MR imaging within 1 year of first MR imaging, with resolution of the previously noted abnormalities. The 13 patients with normal findings on MR images 6 weeks after injury continued with physical therapy with subsequent resolution of their pain. CONCLUSION: Limited MR images of the ankle are useful for detecting talar dome injuries. A significant incidence (57%) of talar dome injury occurred despite normal findings on conventional radiographs in patients with persistent ankle pain.

MR imaging of the shoulder after surgery.

OBJECTIVE: This study examines the usefulness of MR imaging for assessing patients who have undergone shoulder surgery and have persistent postoperative complaints. SUBJECTS AND METHODS: Fifty patients with persistent postoperative shoulder pain underwent MR imaging before second-look arthroscopy. The MR imaging findings were correlated with findings at surgery. RESULTS: With surgical findings as the gold standard, we found MR imaging to be 100% sensitive and 87% specific in revealing full- or partial-thickness supraspinatus tendon tears. MR imaging was 84% sensitive and 87% specific in revealing residual impingement. The positive predictive value of MR imaging for diagnosing partial-thickness tears of the supraspinatus tendon was 56%. With this exception, the MR imaging findings correlated well with findings at arthroscopic second-look surgery. CONCLUSION: In patients who have undergone shoulder surgery, MR imaging is useful in pinpointing disorders and in planning for second-look surgery in patients with persistent postoperative complaints.

Intraosseus ganglia of the wrist.

PURPOSE: To determine the prevalence of intraosseous ganglion cysts in patients with unexplained wrist pain and evaluate the radiographic methods used for their detection. MATERIALS AND METHODS: Four hundred patients with unexplained wrist pain were prospectively examined. All patients underwent standard three-view radiography of the wrist. Patients with cystic areas on conventional radiographs underwent further examination with bone scanning. Ultimately, 17 patients whose bone scans demonstrated increased radiotracer uptake that localized to a particular carpal bone underwent magnetic resonance (MR) imaging. RESULTS: Of these 17 patients, intraosseous ganglion cysts were diagnosed in 15. Some of these ganglia were occult on conventional radiographs and were detected only at bone scanning and MR imaging. CONCLUSION: Intraosseous ganglion cysts in the wrist are more common than previously reported. In some patients, bone scanning, conventional radiography, and/or MR imaging will aid surgical resection that could provide symptomatic relief of unexplained wrist pain.

MRI of anterior cruciate ligament reconstruction.

Eleven asymptomatic patients 1-9 months after arthroscopic assisted anterior cruciate ligament (ACL) reconstruction with autogenous semitendinosus and gracilis tendons as a "neoligament" were studied by MR. Each neoligament was clinically intact. Examinations were performed at 1.5 T with T1- and T2-weighted sagittal and oblique spin echo images in the plane of ACL repair. On MR in 9 of the 11 patients (82%) the ACL neoligament appeared as a smooth well-defined band of low signal intensity along its entire course. In two patients (18%) the integrity of the neoligament could not be determined by MR. Ligaments in which integrity could not be determined demonstrated irregularity or a wavy contour, high signal intensity change within the ligament, or discontinuity of the ligament. We conclude that, contrary to previous reports, MR can demonstrate an intact ACL reconstruction.