Reactive synovitis of the knee joint: MR imaging appearance with arthroscopic correlation.

OBJECTIVE: To evaluate the use of routine MR imaging sequences in detecting and characterizing secondary reactive synovitis of the knee joint using arthroscopy as the standard of reference. DESIGN AND PATIENTS: Fifty consecutive patients with a history of knee pain who were referred for MR imaging and subsequently underwent arthroscopy of the knee comprised the study group. MR images were evaluated for the presence and appearance of synovitis reflected in synovial thickening and irregularity. Synovial thickening was graded on MR imaging as follows: 0=normal, 1=thin line of increased signal intensity, 2=increased signal intensity with frond-like or hair-like projections and a granular appearance of joint fluid. Standard knee imaging protocols were used. RESULTS: The sensitivity, specificity, and accuracy of MR imaging in detecting synovitis compared with arthroscopy were 88%, 97%, and 95%, respectively. Grade 1 synovitis was best seen on proton-density-weighted images, demonstrating increased signal intensity of the synovium against the relatively low signal intensity of the joint fluid. Grade 2 synovitis was best seen on proton-density images and T2-weighted spin echo and fast spin echo images with fat saturation, demonstrating a granular and linear hair-like appearance of joint fluid. Axial and sagittal imaging planes were most helpful in the diagnosis of synovitis. CONCLUSION: Routine MR pulse sequences are useful in identifying the presence and extent of synovial abnormalities. The detection of different stages of synovial pathology should become an important part of the evaluation of the post-traumatic patient as treatment may be altered as a result.

Accuracy of T2-weighted fast spin-echo MR imaging with fat saturation in detecting cartilage defects in the knee: comparison with arthroscopy in 130 patients.

OBJECTIVE: The purpose of this study was to assess the accuracy of routine T2-weighted MR imaging in detecting and grading articular cartilage lesions in the knee compared with arthroscopy. SUBJECTS AND METHODS: We examined 130 consecutive patients who underwent MR imaging and arthroscopy of the knee for suspected internal derangement. MR imaging consisted of axial and coronal T2-weighted fast spin-echo sequences with fat saturation and sagittal T2-weighted spin-echo sequences. Each single plane was evaluated and graded for the presence and appearance of articular cartilage defects using a standard arthroscopic grading scheme adapted to MR imaging. RESULTS: Of the 86 arthroscopically proven abnormalities, 81 were detected on MR imaging. Sensitivity of the T2-weighted fast spin-echo sequence with fat saturation was 61% for the coronal plane alone and 59% for the axial plane alone. Specificity for each plane was 99%. Sensitivity for the sagittal T2-weighted spin-echo sequence was 40%, and specificity was 100%. Sensitivity of the combination of axial and coronal T2-weighted fast spin-echo sequences with fat saturation and sagittal T2-weighted spin-echo sequence compared with arthroscopy for revealing cartilage lesions was 94%, specificity was 99%, and accuracy was 98%. Sensitivity of coronal and axial T2-weighted fast spin-echo sequences with fat saturation was 93%, and specificity was 99%. Fifty-five lesions (64%) were identically graded on MR imaging and arthroscopy. Seventy-eight lesions (90%) were within one grade using MR imaging and arthroscopy, and 84 lesions (97%) were within two grades using MR imaging and arthroscopy. CONCLUSION: T2-weighted fast spin-echo MR imaging with fat saturation is an accurate and fast technique for detecting and grading articular cartilage defects in the knee. The combination of the axial and coronal planes offers sufficient coverage of articular surfaces to provide a high sensitivity and specificity for chondral defects.

A practical approach to imaging of the shoulder with emphasis on MR imaging.

Our understanding of shoulder disorders has changed considerably as a result of improved diagnostic tools, such as arthroscopy and multiplanar imaging modalities. The diagnosis of the cause of shoulder pain can be difficult because a spectrum of disorders, including cervical spine disease, acromioclavicular arthritis, and shoulder instability. Impingement and denervation syndromes can present with similar clinical findings. Accurate depiction of anatomic abnormalities is important for treatment planning. The purpose of this article is to report on the application of available imaging modalities, with emphasis on MR imaging. A strategy for the appropriate use of these studies and their variations of technique is also provided.

Elongation of arthroscopically tied knots.

It has been postulated that some arthroscopic shoulder stabilization failures may be due to knot slippage. In an effort to improve arthroscopic technique, we performed tensile testing on four arthroscopically tied knots with two commonly used suture materials. Handtied square knots served as controls. Sutures of No. 1 Maxon and No. 1 Ticron were used. Four types of sliding knot configurations were tested: the overhand loop, the Duncan loop, the Roeder knot, and the Snyder knot. Knots were tied via a knot pusher, and testing was performed in a normal saline-filled thermoplastic chamber. Knots were tied around two rings connected to a Bionix 858 materials testing apparatus. The knots were tested under conditions of cyclic loading and loading to failure. Results of the testing revealed that the most important factor in knot security was the type of suture material, although there were differences with the type of knot. With the Maxon suture, there was significantly decreased ultimate failure load of all of the arthroscopically tied knots compared with handtied square knots. Knots tied with Ticron were similar in strength for both arthroscopically and handtied groups. The surgeon who chooses a monofilament absorbable suture should be aware that a high percentage of knots fail under low load cyclic testing, and that all of these knots were inferior to handtied square knot controls in testing to failure.

Common disorders of the shoulder.

The shoulder joint is a complex articulation requiring coordinated interaction of bone and soft-tissue structures for normal function of the upper extremity. Trauma or overuse of the shoulder may lead to dysfunction requiring medical evaluation. Most shoulder problems may be treated without surgery by the primary care physician. Appropriate conservative management depends on an accurate diagnosis of the underlying pathology.

Heterotopic ossification of the patellar tendon following intramedullary nailing of the tibia: report on two cases.

Heterotopic ossification (HO) of the patellar tendon following intramedullary nailing of the tibia for fracture, which has not been previously documented, occurred in 2 of 31 patients reviewed who had adequate follow-up after this procedure. One suffered grade IV HO and the other grade II HO using a modification of the Brooker classification. The patient with grade IV HO had serious disability from pain and decreased range of motion. Risk factors previously suggested were associated with the formation of heterotopic bone in our two patients. These factors included head injury and long-term hypoxemia.

Comparison of the effect of temperature on kidney cortex mitochondria from rabbit, dog, pig, and human: Arrhenius plots of ADP-stimulated respiration.

The effect of temperature on the rate of ADP-stimulated respiration of mitochondria from dog, rabbit, pig, and human kidney cortex mitochondria was plotted according to the Arrhenius relationship. The temperature at which the plot demonstrated a break was at 15 degrees C for mitochondria from dog, pig, and human kidneys. The discontinuity occurred at 10 degrees C or less for mitochondria from rabbit kidneys. This difference suggests that mitochondria from rabbit kidneys undergo a lipid-phase transition at lower temperatures than for other species commonly used in experimental renal preservation. The implications of this difference suggest caution in using results obtained with rabbit kidneys for comparison to results obtained from hypothermic renal preservation of other species kidneys. Apparent fluidization of dog kidney mitochondrial membranes with adamantine abolished the discontinuity in the Arrhenius plot.