Ring sequestrum: radiographic characteristics of skeletal fixation pin-tract osteomyelitis.

Major pin-tract infections are a potentially dangerous complication associated with the use of skeletal transfixation pins. The presence of a characteristic radiographic finding, the ring sequestrum, is virtually diagnostic of this abnormality. The clinical and radiographic findings in seven patients treated for this complication are presented. Thermal necrosis without infection presents as a zone of sclerosis around the tract. A narrow, radiolucent halo may surround the dense bone. When a narrow ring sequestrum is surrounded by a radiolucent halo, there is associated infection.

Unique features of group B streptococcal arthritis in adults.

Group B streptococci have rarely been reported to cause serious infection in adults and even less frequently to result in septic arthritis. We reviewed our clinical and radiologic experience with septic arthritis and uncovered five cases of infectious arthritis caused by group B streptococci. Unlike previously described patients with monoarthritis and complete recovery, our patients displayed polyarticular involvement. The infection in some cases was aggressive, resulting in destruction of multiple joints. Therefore, the series supports the view that this uncommon pathogen may produce an aggressive polyarthritis with the potential for serious functional damage and permanent morbidity. Culture and identification of a group B streptococcal pathogen and prompt institution of therapy can help avoid these complications.

Computed and conventional arthrotomography of the glenohumeral joint: normal anatomy and clinical experience.

The glenohumeral joint was studied in 25 cadavers and 136 patients using computed arthrotomography (CAT) and conventional arthrotomography (AT) to assess shoulder instability. Cadaver shoulders were injected with air or latex, sectioned with a band saw, and normal articular anatomy outlined. CAT was performed in 81 patients and characterized the glenoid labrum as normal, abnormal, or detached in 38 of the 44 patients who had surgery or arthroscopy (sensitivity, 96%; accuracy, 86%). Hill-Sachs defects were seen in 20 out of 29 patients with anterior labral abnormalities, while bicipital tendon abnormalities were evident on CAT in 6. Of 55 patients who had AT, the status of the labrum was clarified in 13 of the 16 patients who had surgery or arthroscopy (sensitivity, 86%; accuracy, 81%). Both methods can characterize the labrum; however, CAT is more comprehensive and appears ideal for both detection of Hill-Sachs defects and imaging the bicipital tendon. CAT requires less technical expertise and radiation than AT and is tolerated better by patients in pain.

Triplane fracture of the distal tibial epiphysis: radiographic and CT studies.

We analyzed six cases of triplane fracture of the ankle and reviewed the literature. A previously undescribed fracture pattern was identified in one patient. CT studies proved to be useful diagnostic tools in the evaluation of triplane fractures when operative reduction was contemplated.

Digital arthrography in the evaluation of painful joint prostheses.

Digital arthrography was accomplished in 16 patients who had painful prostheses. In each instance, resulting arthrographic abnormalities were compared with those apparent on subsequent overhead radiographs. Results indicate the potential value of the digital technique in this clinical setting. The examination is easy to perform and rapid, and allows the examiner to view the changing images in the subtraction mode. Image manipulation and enhancement are also possible.

Replantation of digits or hands followed by destructive joint disease.

The clinical records and radiographs of 45 patients who had undergone replantation of a total hand, or a part thereof, were reviewed in order to determine the prevalence and the type of articular changes occurring distal to the site of anastomoses. In three patients, destructive joint changes were observed, consisting of bony fragmentation, spiculation, and cystic or erosive lesions. These changes, which developed between five and ten months after replantation, are most likely neuropathic or osteonecrotic in pathogenesis.

Clues to the initial radiographic evaluation of skeletal trauma.

Significant injuries to the musculoskeletal system usually result in a radiographic abnormality. The physician is faced with the problem of recognizing and correctly interpreting these abnormalities. The best way to recognize an abnormality is to thoroughly understand what is normal. Knowledge of normal appearances and relationships will allow identification of even subtle fractures and dislocations.

The nature of humeral pseudocysts.

In an effort to define the nature of the humeral pseudocyst, we examined a large number of macerated specimens. The area of rarefaction, located in the lateral aspect of the proximal humerus, may be a prominent radiographic finding in young individuals. In older individuals, with loss of trabecular bone in the proximal portion of the humerus, a less obvious rarefaction is present. Precise radiographic features allow differentiation of this normal finding from significant lesions in this region.

Shoulder impingement syndrome: radiographic evaluation.

The impingement syndrome is an important source of shoulder pain that occurs when the bony and soft-tissue structures of the superior aspect of the shoulder encroach upon the coracoacromial ligamentous arch during abduction of the arm. Subacromial bursitis, bicipital tendinitis, and rotator cuff disruptions are common sequelae of this abnormality. The presence of bony excrescences arising from the anteroinferior aspect of the acromion and of flattening and sclerosis of the greater tuberosity of the humerus is an important plain radiographic sign of the impingement syndrome. Fluoroscopy, shoulder arthrography, subacromial bursography, and bursotomography are fundamental diagnostic imaging modalities in this disorder.

Intracapsular pressure monitoring during arthrographic evaluation of painful hip prostheses.

Aspiration-arthrography with continuous monitoring of intraarticular pressure and volume was performed on 10 consecutive patients with painful total-hip arthroplasties. Five of these patients demonstrated clinical and arthrographic evidence of adhesive capsulitis, a condition that was associated with a dramatic rise of intraarticular pressure as increasing amounts of contrast material were introduced. The precise etiology of adhesive capsulitis is not clear.

Computed tomography of the normal radioulnar joints.

Computed tomography followed by sectional radiography and photography as performed on eight cadaveric specimens in order to define the anatomy and normal motion of both the proximal and the distal radioulnar articulations. Osseous landmarks were defined that allowed measurement of rotation at the glenohumeral, proximal radioulnar and distal radioulnar joints as well as rotation between humerus and radius and between humerus and ulna. Findings included the absence of independent ulnar rotation and the presence of normal translatory motion at the distal radioulnar articulation that may be misinterpreted as evidence of subluxation of the distal ulna.

Computed tomography of the normal soft tissues of the wrist.

Computed tomography and sectional radiography and photography were performed on eight cadaveric wrist specimens in order to define the soft tissue structures of the normal wrist. Three specific levels were analyzed in detail: the levels of the distal radioulnar joint, of the pisotriquetral joint, and of the hook of the hamate. All soft tissues, with the exception of arteries and veins, were well demonstrated with computed tomography. In particular, the contents of both Guyon's canal and the carpal tunnel could be delineated. The position of the extensor carpi ulnaris tendon and sheath could also be evaluated. Contrast opacification of the flexor tendon sheaths and palmar synovial sacs did not contribute to the analysis. Computed tomography appears to be an important imaging modality in the evaluation of significant clinical problems, including the carpal tunnel and ulnar tunnel syndromes and subluxation of the extensor carpi ulnaris tendon.

The bicipital groove: radiographic, anatomic, and pathologic study.

By using patient radiographs and pathologic specimens, the bicipital groove of the humerus was studied to determine the normal configuration and common abnormalities of this region. Factors analyzed in evaluating the bicipital groove included the medial wall angle, depth and width of the intertubercular sulcus, and presence or absence of bony spurs arising from the floor or medial wall of the groove. The supratubercular ridge was observed as an osseous protuberance in about one-half of the population; it does not seem to be of pathologic significance. A specific radiographic projection is described, which allows evaluation of the bicipital groove.