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Juvenile osteochondritis dissecans is a diagnosis based on plain radiographic appearance. Although it is on occasion difficult to decide whether the observed radiographic abnormality represents osteochondritis dissecans or physiologic irregular ossification, 50% of children should evidence healing with nonoperative activity modification management. In those who fail this regimen, the majority require simple drilling of the lesion through intact articular cartilage.

Thirty-six consecutive ankle arthroscopies from 1991 to 1996 were reviewed. Indications for arthroscopy were loose bodies, osteochondritis dissecans, and post traumatic and degenerative ankle joints. Thirty patients were re-examined 5-60 months postoperatively (median follow-up 12 months). Among twelve patients with an ankle fracture, a loose body was arthroscopically removed from eight patients while the remaining four patients were treated with local synovectomy. Of these twelve patients, nine had no symptoms at follow-up. Of eight patients with initial ankle sprain, four had no symptoms after removal of soft tissue lesions. Of five patients with osteochondritis dissecans treated by drilling through the fragment into the subchondral bone or, alternatively, removal of small pieces, two had no symptoms at follow-up. Five patients with degenerative joint disease had no improvement after arthroscopical debridement. Ankle arthroscopy seems to provide an effective treatment of loose bodies and soft tissue impingement, but the results are not convincing in osteochondritis dissecans and are poor in degenerative ankle joint disease.

Osteochondral loose bodies are an uncommon finding in the temporomandibular joint (TMJ), but occur relatively frequently in large joints such as the knee, elbow, hip, wrist, and ankle. Loose joint bodies can be divided in three groups: 1) synovial chondromatosis; 2) osteochondral fracture fragments and; 3) cases of degenerative arthritis or avascular necrosis. The most common clinical features of loose joint bodies are pain, swelling, joint noise and impaired joint movements. A case of loose joint bodies of the temporomandibular joint is presented. The pantomograph and lateral cephalograph revealed several irregularly shaped, variably sized radiopaque structures in the region of the right temporomandibular joint. CT and MR scans confirmed the initial diagnosis. The dimensions of the loose joint bodies varied from 1-2 to 5-6 mm. In this patient, the loose joint bodies may have been secondary to osteoarthritis, may have preceded and caused the degenerative changes, or may be only a coincidental finding.

Hip arthroscopy can be performed on an outpatient basis and has a shorter period of rehabilitation than is necessary after an open hip arthrotomy or reconstruction. The procedure makes possible accurate diagnosis and treatment of acetabular labral tears and loose bodies. Further advancements are necessary in optical equipment; manual and motorized equipment; and simple, reliable traction devices specific for this procedure. Refinements in patient selection and the increased availability of specific outcome data will help to define the role of hip arthroscopy in orthopedic practice.

Purpose: To determine the effectiveness of magnetic resonance (MR) imaging in the diagnosis of anterolateral impingement of the ankle., Materials and Methods: MR images were reviewed in 12 patients (12 ankles) with arthroscopically proved anterolateral impingement and in 19 control subjects (20 ankles) with diagnoses other than impingement. MR images were scored by means of consensus of two musculoskeletal radiologists and independently by a third radiologist. Patients underwent imaging at 1.5 T, with use of standard imaging sequences and a dedicated extremity coil., Results: For the consensus reading, the sensitivity, specificity, and accuracy of MR imaging for the diagnosis of impingement were 42%, 85%, and 69%, respectively. The frequency of lateral gutter fullness and anterior talofibular ligament thickening on MR images was higher in the 12 ankles with impingement (seven [58%] and seven [58%] ankles, respectively) than in the 20 control ankles (seven [35%] and five [25%] ankles, respectively), but these trends did not reach statistical significance. Interobserver agreement for anterior talofibular ligament thickening was high, whereas that for lateral gutter fullness was fair., Conclusion: Conventional MR imaging of the ankle is insensitive for anterolateral impingement. Anterior talofibular ligament thickening and soft-tissue fullness in the lateral gutter may be suggestive of the diagnosis, but the reliability of the latter finding is questionable.

The radiological findings of ultrasound, CT and MR of a case of bilateral subacromial bursitis with macroscopic rice bodies is described. The previous literature is also reviewed.

We assessed MR findings of throwing injuries occurring in the elbow joint using three-dimensional Fourier transform (3DFT) and short tau inversion recovery (STIR) images. MR images of 63 elbows in 63 male patients aged from 10 to 32 years (mean age, 15 years 11 months) suffering from throwing injury were visually analyzed. The sequences used for the study were axial 3DFT and coronal STIR. Full-thickness tears were demonstrated in 34 elbows and undersurface tears of the ulnar collateral ligament (UCL) were demonstrated in five elbows. Thirty loose bodies were detected in 14 elbows. Cartilaginous damage due to osteochondral injury was depicted in 21 elbows. Multiplanar reformatted images using the 3DFT data set were useful for assessing torn UCLs, intraarticular loose bodies, and capitellar fragments. Full-thickness tears and undersurface tears of the UCL could be differentiated with STIR images. 3DFT and STIR sequences depict various aspects of throwing injuries occurring in the elbow.

Acute patellar dislocation and relocation produces major forces at the articular surfaces. Articular injury was assessed in 48 patients, 24 boys and 24 girls (mean age, 14 years), with acute, initial, noncontact patellar dislocations. Correlation of the findings of radiographic and arthroscopic examinations was done. Eleven of the 48 patients (23%) had radiologic diagnoses of articular injuries. Thirty-four of the 48 patients (71%) had arthroscopic evidence of articular damage, 32 osteochondral and 2 chondral injuries. Eight of the 28 (29%) arthroscopically identified osteochondral loose bodies (4 to 20 mm) were identified radiologically. Overall, only 11 of the 34 (32%) arthroscopically documented articular injuries were defined by preoperative radiographs. These standard radiographs provided limited information for management decisions. Poor results after patellar dislocation treatment may involve nonrecognition of articular compromise.

The bicipito-radial bursa, which lies at the biceps tendon insertion on the radial tuberosity, is a rare site of chronic bursitis. We describe the clinical, radiological, and pathological findings in a case complicated by multiple rice body formation. In so doing, we describe MR appearances that allow discrimination of this entity from both synovial chondromatosis and pigmented villonodular synovitis.

A case of 15 years old schoolgirl with synovial chondromatosis of the right shoulder is presented. The diagnosis has been confirmed by MRI. At arthroscopy approximately 70 oval loose bodies 5-8 mm in size have been removed. Postoperatively, no complication occurred. The case presented demonstrates advantage of arthroscopic treatment of this rare condition.

Impingement syndrome is usually caused by encroachment on the rotator cuff of the acromion, coracoacromial ligament, acromioclavicular joint or coracoid process. Bursal causes of impingement are rare but include rheumatoid thickening, and thickening from previous and iatrogenic causes such as sutures, pins, or wires left from previous surgery. We report a case of synovial osteochondromatosis presenting as chronic impingement syndrome. Synovial osteochondromatosis may be difficult to differentiate from chronic calcific tendinitis, but we describe a radiological sign and its anatomical basis that can differentiate between the two. If densities are seen on plain radiographs distal to the greater tuberosity, then loose bodies within the subacromial bursa should be considered.

In the past several years, the role of MR imaging in diagnosing pathologic conditions of the elbow has dramatically increased. Aside from imaging soft-tissue tumors, it can accurately visualize partial and complete tears of tendons and ligaments, as well as displacement of epiphyseal fractures in children. Its role in identifying loose bodies, particularly when they are nonosseous, and areas of osteochondritis dissecans has also increased. The use of MR imaging for diagnosing neuropathies, particularly when electrodiagnostic studies are negative, offers exciting possibilities as additional technical improvements are developed.

Objective: MR arthrograms were retrospectively reviewed for susceptibility artifacts induced by accidental injection of a small amount of gas when paramagnetic contrast solution was injected. A pitfall to interpretation, an unusual distribution of intraarticular gas into the sheath of the long biceps tendon that resembled a rope ladder, was observed and compared with findings of bicipital tenosynovitis., Conclusion: Intraarticular gas contamination during MR arthrography must be differentiated from intraarticular loose bodies and findings of bicipital tenosynovitis. Most reliable for the differential diagnosis are the different shapes and sizes of the gas-induced susceptibility artifacts on spin-echo and gradient-recalled echo images.

MR imaging provides clinically useful information in assessing the elbow joint. Superior depiction of muscles, ligaments, and tendons as well as the ability to visualize nerves, bone marrow, and hyaline cartilage directly are advantages of MR imaging relative to conventional imaging techniques. These features of MR imaging may help to establish the cause of elbow pain by accurately depicting the presence and extent of bone and soft-tissue pathology. Ongoing improvements in surface coil design and newer pulse sequences have resulted in higher quality MR images of the elbow that can be obtained more rapidly. Recent clinical experience has shown the utility of MR imaging in detecting and characterizing disorders of the elbow in a noninvasive fashion.

Purpose of the Study: We have retrospectively studied the results of arthroscopic removal of loose bodies in the elbow. The aim of the study was to determine if the etiology of the loose bodies could be considered as a criteria for technical difficulty and clinical prognosis., Material: 16 patients (11 men and 5 female) had an elbow arthroscopy for loose bodies removal. Their average age was 29.5 years (range: 16-49). The post-operative results were recorded in their medical files with an average follow-up of six months., Methods: In each case we have determined the etiology of the intra-articular loose bodies. The results were analyzed according to technical difficulty and clinical outcome., Results: The etiology of the loose bodies was 8 chondromatosis, 4 osteochondritis dissecans and 4 post-traumatic osteoarthritis. The removal of the loose bodies was possible in 13 cases. Three arthroscopies were interrupted because of arthritic joint space narrowing. Twelve patients with primary chondromatosis and osteochondritis dissecans were improved. We did not find any significant clinical improvement in osteoarthritic elbows. A correlation between the results and the etiologies could therefore be shown., Discussion: In arthroscopic removal of elbow loose bodies, technical difficulties and clinical results are correlated to the etiology of the loose bodies and also to the statement of the osteochondral surfaces.

In a prospective, randomized study, 47 patients underwent arthroscopic evaluation of the knee in an operating room setting with both a standard rod-lens arthroscope and a newer flexible optical catheter fiberoptic system. The goal of the study was to assess the diagnostic accuracy of the newer catheter system, which is recommended for use in the office setting. Forty-four patients were included in the data analysis, three were eliminated because we were unable to perform an adequate examination with the catheter scope secondary to intraarticular adhesions or excessive bleeding. A comparison of the two systems revealed an overall underestimation and underrecognition of intraarticular knee pathologic changes. Anterior cruciate ligament tears were missed in 3 of 21 knees; no posterior cruciate ligament tears were detected by the rod-lens arthroscope in 44 knees, but one false-positive result was "seen" using the optical catheter device. Similar trends in diagnosis (sensitivity, 25% to 67%; specificity, 96% to 99%) were seen for tears of the medial and lateral menisci, chondral lesions, and the identification of loose bodies. We conclude from the results of this study that the use of the optical catheter system for arthroscopic evaluation and treatment of the knee in the office setting may result in a significant compromise in visual acuity, resulting in missed and incorrect diagnoses.

Although magnetic resonance imaging (MRI) of the knee is known to be an accurate technique for diagnosing soft tissue disorders of the knee, the value of MRI in improving patient outcome is controversial. The purpose of this project was to study the value of MRI in a subgroup of patients with knee pain and disability whose diagnosis was uncertain after standard orthopaedic evaluation. An extensive database was recorded prospectively for each of 208 patients providing clinical data as well as diagnoses from clinical, MRI, and surgical observations. These data were analyzed to determine the effect of MRI on diagnosis and patient outcome regarding surgical decision making. The overall diagnostic accuracy of MRI was determined to be 97% in patients undergoing arthroscopy. MRI differed from the clinical diagnosis in 33% of cases, the most common variance being diagnosis of meniscal tear. After combining the MRI and clinical information, surgical decision making was altered in 27% of cases. In a group of patients with acute knee symptoms, the decision not to proceed with surgery was made in 64% of cases. The study shows that MRI of the knee is a valuable tool for augmenting the diagnostic process. The data further show that MRI is a cost-effective technique for avoiding unnecessary surgery and affects patient outcome by improving surgical decision making.

Purpose: To compare magnetic resonance (MR) imaging and MR arthrography with computed tomography (CT) and CT arthrography in the detection of intraarticular bodies in the knee., Materials and Methods: Cuboid (3- or 6-mm-long sides) osseous and cartilaginous bodies were implanted in 16 cadaveric knee specimens. MR imaging was performed with T1-weighted spin-echo (SE), T2-weighted SE, proton-density-weighted SE, gradient recalled acquisition in the steady state (GRASS), and spoiled GRASS sequences. MR arthrography was performed in two phases with saline and 2 mmol/L gadopentetate dimeglumine. CT and CT arthrography were performed in the transaxial plane., Results: MR arthrography yielded the highest accuracy for the detection of osseous and cartilaginous bodies combined (92%) and was significantly (P < .01) better than MR imaging (57%-70%), CT arthrography (80%), and CT (74%). Accuracy of CT arthrography was significantly better than that of MR imaging and that of CT. Accuracy of saline-enhanced MR arthrography was significantly inferior (P < .001) to that of gadolinium-enhanced MR arthrography., Conclusion: MR arthrography is the best imaging technique for detection of individual intraarticular bodies. CT arthrography is the second most accurate method. Spoiled GRASS and T2-weighted SE sequences are the most accurate at MR imaging. The presence of intraarticular fluid and performance of saline-enhanced MR arthrography improve detectability of intraarticular bodies.

With an understanding of the normal anatomy of the elbow and a pertinent clinical history, MR imaging of the elbow need not be a source of fear and confusion for the MR radiologist. Because positioning and scan planning are not as straightforward as they are with other joints such as the knee or shoulder, these processes can be time-consuming. The position in which the patient is optimally scanned is inherently uncomfortable. In a busy MR center with rigorous time constraints, these factors and patient fatigue can limit the time available to acquire images. Thus, a tailored approach to designing a scanning protocol for the elbow is warranted. The preceding discussion attempts to address a streamlined approach to MR imaging of the more common pathologic processes occurring around the elbow. The sequences we have described may require some modification on different imaging systems to take into account variations in field strength and to account for disparity in hardware and software parameters of different vendors. In combination with the information provided in the clinical history, the guidelines we provide should serve as a general template upon which the practicing radiologist can base his or her approach to MR imaging of the elbow.

Improvements in techniques and instrumentation are extending the diagnostic and therapeutic indications for ankle arthroscopy. We aimed to study the diagnostic and therapeutic benefits and complication rate from 112 consecutive ankle arthroscopies performed between 1991 and 1994 under local and general anaesthesia. One-hundred and twelve outpatient ankle arthroscopies were performed in 72 male and 37 female patients, 16-64 years old. The patients were comparable in terms of gender and age in the arthroscopies done under local (n = 69) and the arthroscopies done under general anaesthesia (n = 43). The indications for surgery were pain in 75%, instability in 15%, limited function in 7% and swelling in 4%, and these criteria were similar in both groups. Antero-medial and anterolateral portals were used in all cases. No tourniquet was used and an external distractor was used in one case only. In 64 cases (57%) surgery was performed and included synovectomy, removal of loose bodies, shaving drilling of osteochondritic or other cartilage lesions, resection of impinging osteophytes, fibrosis and meniscoid lesions. In 95 ankles (85%) a definite diagnosis was established. Comparable diagnostic and therapeutic potentials were found between local and general anaesthesia. The complication rate was low. One patient who was operated on under general anaesthesia sustained a deep infection, and three suffered minor superficial nerve injuries. In conclusion, ankle arthroscopy may be performed under local or general anaesthesia with similar diagnostic value and with a low complication rate.

Meniscal ossicles are rare and may cause diagnostic difficulty on plain radiograph at presentation. Magnetic resonance imaging is useful in detecting meniscal ossicles because their characteristic appearance on MRI can differentiate them from other disease. Arthroscopy can also diagnose the meniscal ossicle, which in our patient appeared as a swelling in the meniscus. If the patient is asymptomatic before the time of diagnosis, removal of the ossicle may not be indicated and, as with our patient, normal function is possible with the ossicle retained.

Magnetic resonance (MR) arthrography is possible in any joint in which standard arthrography is performed. The diagnostic potential of this technique is optimized in the assessment of complex anatomical structures and intra-articular abnormalities that are difficult to visualize on conventional MR images. This paper presents the most common applications of MR arthrography in the shoulder, hip, knee, ankle, elbow and wrist, and explores the clinical indications in which MR arthrography adds the greatest benefit compared to standard arthrography and conventional MR imaging. Arthrographic MR images are most valuable in the evaluation of glenoid and acetabular labra, tendons of the rotator cuff, post-operative menisci, osteochondral fractures and loose bodies.

A 45-year-old patient sustained a traumatic dislocation of 1 hip. During a 29-year period, 10 to 13 multiple calcified loose bodies developed slowly in the hip. These first grew in size and became very radiodense, but later showed progressively less radiodensity. Progressive osteoarthritis of the hip was the indication for hip arthrotomy. The loose bodies had become reattached to the synovial surface of the hip joint and were revascularized, having converted from calcified cartilage to bone. This case dramatically shows the body's mechanism for attempting to remove loose bodies from joints.

We report the MR appearance of a meniscal ossicle, which is an unusual etiology for knee pain. The role of MR in differentiating a meniscal ossicle from a loose body is presented. The MR images also demonstrated associated tibial cartilage thinning and a possible meniscal tear. These MR findings led to arthroscopic treatment rather than conservative management. A review of the literature on meniscal ossicles is also presented.

Arthroscopy of the elbow has proven to have a diagnostic and therapeutic benefit. Removal of loose bodies and a thorough evaluation of associated intra-articular pathologies are possible without arthrotomy. The authors have found this procedure to be safe and effective in the treatment of loose bodies of the elbow and other associated pathologies.

Loose bodies are a rare cause of temporomandibular joint symptoms. Their main source is synovial chondromatosis. We report on clinical findings, diagnostic methods, treatment choices and outcome following the removal of loose bodies in 10 patients. Seven patients were evaluated and treated by means of arthroscopy, while in three patients open arthrotomy was performed. In five patients, no diagnostic imaging technique had demonstrated the presence of loose bodies prior to arthroscopy. In six patients, histology revealed synovial chondromatosis. In four patients, osteochondral fragments alone were found. Until now, the recommended treatment of choice for the removal of all loose bodies and of affected synovial tissue required open arthrotomy. We conclude that the advantages of arthroscopy consist in locating loose bodies that are not detectable radiologically and in reducing operative trauma.

Preoperative assessment of posttraumatic flexion contracture of the elbow includes plain radiographs and tomograms, which are difficult to obtain in the coronal plane due to the contracture. We conducted this study to determine the usefulness of MR imaging in the work-up of these patients. Twelve patients with flexion contracture of the elbow were studied. In addition to standard spin-echo sequences, a sagittally acquired spoiled gradient-recalled echo 3D data set of the flexed elbow was obtained and reformatted coronally using a curved plane of reconstruction. The MR findings were compared to the plain films, tomograms and surgical results. MRI allowed identification of loose bodies that were sometimes poorly visualized, or not seen, on plain films, and demonstrated degenerative changes equally as well as tomograms. MR showed soft tissue abnormalities including capsular and collateral ligament thickening. Curvilinear reconstructions were helpful in the assessment of collateral ligaments in patients with severe contractures. We conclude that MR is useful in the evaluation of elbow flexion contractures, particularly in assessing soft tissue causes.

Synovial cysts are most frequently found about the knee. Less commonly they have been described at the shoulder, elbow, ankle, and hip joints. Synovial cysts of the shoulder are associated with rheumatoid arthritis, osteoarthritis, chronic steroid use, Charcot joint disease, and long-standing rotator cuff tears. Although often asymptomatic, patients may present complaining of pain, loss of joint motion, or presence of an unexplained mass. The authors present the case of an elderly man with a very large synovial cyst presenting as an anterior chest wall mass.

Two children, aged 5 and 11 years, presented clinically with ankle pain and a mobile bony hard lump in the ankle. Radiological examination revealed a large radio-opaque shadow in relation to the talus. Intraoperatively, a loose body was found. It resembled a detached exostosis with cartilaginous cap and was confirmed histologically as an osteochondroma. In the older child, there was a remnant stalk attached to the lateral surface of the talus. In the younger child, the exostosis probably came from the talus as the osteochondroma could not originate from the epiphyses that form the ankle mortise.

Objective: In routine MR imaging of the temporomandibular joints, a low-signal structure posterosuperior to the mandibular condyle is occasionally seen on the two-dimensional gradient-echo sequence. The structure is ovoid and may have a higher-signal core, simulating a loose body within the joint. We undertook a clinical and cadaveric study to determine the cause of this finding., Materials and Methods: In a clinical study, we reviewed the MR images of 100 temporomandibular joints. We scored each joint for the presence and appearance of a low-signal structure posterosuperior to the mandibular condyle: type 1 was ovoid with a low-signal rim and a higher-signal core, type 2 was ovoid with uniformly low signal, type 3 was a low-signal structure inseparable from the posterior wall of the glenoid fossa, and type 4 was normal. Using this scoring system, we determined the appearance and frequency of the finding on two-dimensional gradient-echo, T1-, T2-, and proton density-weighted images. To determine the cause of the finding, we correlated the imaging and anatomic findings in a cadaveric specimen., Results: Of the 100 MR images of joints reviewed, 22 showed a type 1 structure, 24 a type 2 structure, 11 a type 3 structure, and 43 were normal. The finding was seen only on the two-dimensional gradient-echo sequences, never on the spin-echo sequences. Correlation between the imaging and anatomic findings in the cadaveric specimen showed that the finding was caused by the superficial temporal artery. The variability in its appearance is thought to result from the complex manifestations of flowing blood within this artery., Conclusion: The finding posterosuperior to the mandibular condyle seen on two-dimensional gradient-echo MR images is a flow phenomenon within the superficial temporal artery. Recognition of the nature of this finding will avoid mistaking it for disease, such as an intraarticular loose body.

Magnetic resonance imaging (MRI) was performed on seven patients with aseptic osteonecrosis (n = 4) and osteochondritis dissecans (OCD; n = 3) of the elbow. Precontrast MRI was superior to plain radiographs, which did not show any abnormality in three cases of osteonecrosis. On gadopentetate-dimeglumine-enhanced T1-weighted images, which were obtained in three patients with osteonecrosis and three patients with OCD, all cases of osteonecrosis demonstrated homogeneous enhancement of the lesions. All cases of OCD were diagnosed on plain radiographs. On MRI one showed significant enhancement of the loose body. In another case an incompletely enhancing loose body was surrounded by a diffusely enhancing region. In the third patient only a small marginal enhancement of the defect was observed. Our results suggest that MRI can improve the accuracy in diagnosis of aseptic osteonecrosis of the elbow. The use of gadopentetate dimeglumine allows the viability of the lesions or the loose bodies to be demonstrated and reparative tissue to be detected.

Localized pigmented villonodular synovitis is a rare condition of the knee that may present with symptoms suggesting internal derangement. We report a case of juvenile patient who presented with a 1-year history of signs and symptoms of a loose body in the knee. Radiographic examination and MRI were within normal limits. The lesion was treated arthroscopically by resection.

Technical improvements in MR imaging have resulted in the ability to detect soft tissue and bone pathology, with great facility in the elbow joint. This allows application of MRI to the elbow in the same valuable ways it has been used in other joints for a much longer period.

The case presented is a 22-year-old man with previously treated synovial chondromatosis of the shoulder. He subsequently presented with pain and tenderness above the biceps tendon. Magnetic resonance imaging and radiographs revealed recurrent synovial chondromatosis in the biceps tendon sheath. The patient underwent an open procedure to remove the loose bodies and partial tenosynovectomy. The patient has subsequently done well and resumed normal activities. To our knowledge there are no reported cases of synovial chondromatosis involving the biceps tendon sheath in the literature.

Objective: The purpose of this prospective study was to compare the value of MR imaging in the detection of injuries associated with acute acetabular fractures (femoral head fracture, free fragments within the hip joint, and injury to the sciatic nerve) with the value of preoperative CT examinations, intraoperative inspection, intraoperative somatosensory evoked potentials (SEP), and clinical neurologic examinations., Subjects and Methods: Coronal fat suppressed long TR/TE and unenhanced and contrast-enhanced T1-weighted MR images were obtained preoperatively in 37 patients with acetabular fractures. The sciatic nerve was assessed for injury and the femoral head was assessed for fracture, dislocation, and contusion. MR results were compared with CT findings for acetabular fractures and fractures of the femoral head. The appearance of the sciatic nerve on MR images was correlated with intraoperative changes in SEP and results of the clinical neurologic examination., Results: Although MR images showed acetabular fractures, intraarticular fragments were often obscured. Fragments were readily apparent on CT scans. MR images showed fracture of the femoral head in 10 (27%) of 37 cases. Nine of these fractures also were seen on CT scans. MR images showed subchondral contusion of the femoral head in 24 (65%) of 37 cases. The same areas appeared normal on CT scans. MR images of the sciatic nerve obtained after injection of contrast material showed intraneural or perineural enhancement in all patients with either changes in baseline SEP (n = 19) or preoperative neurologic deficit (n = 10). Although baseline changes in SEP were more common with intraneural enhancement, the difference in the prevalence of neurologic deficits was not significant. The preoperative enhancement pattern alone could not be used to predict a neurologic deficit., Conclusions: MR imaging of acetabular fractures can be used to detect subclinical injury of the sciatic nerve and occult injuries of the femoral head not readily apparent on CT scans. However, intraarticular fragments may be obscured.

The correct therapy of osteochondritis dissecans in patients under 16 years is very important to prevent the knee joint from secondary arthritis. We analysed clinical, radiological and with MRI the long term (10 years) results of a follow-up study on 36 patients under 16 years with 42 operatively treated osteochondritis dissecans of the knee joint. There were excellent and good results in 81% of the patients. After an average of 10 years there were no signs of arthritis which would necessitate any treatment.

Two cases of bursitis complicated by rice bodies (C.O., corpora oryzoidea) are described. One case occurred after local elbow trauma, in the other case tuberculous bursitis was found. C.O. is a rare manifestation of fibrinous inflammation, seen not only in TB but also, perhaps more frequently, in rheumatoid conditions. Removal of the bursa and C.O. followed by microscopic investigation is recommended.

Eighty-four consecutive cases of ankle arthroscopy performed between 1985 and 1990 were reviewed. These patients had all undergone conservative treatment for at least six months for chronic ankle pain. This consisted of non-steroidal anti-inflammatory agents, physiotherapy and/or immobilisation. Arthroscopy was performed when there was no response to conservative treatment. Eighty-one percent (68) of the patients were between the ages 20 and 29 years. Eighty-nine percent (75) were male. The most common lesions identified were transchondral fractures, localised synovitis, osteoarthritis and loose bodies. These were treated by arthroscopic surgery which included debridement, removal of loose bodies and abrasive chondroplasty. All the patients were followed up for at least one year or until they were asymptomatic. Excellent results were observed in transchondral fracture, localised synovitis associated with chronic lateral ligament instability, loose bodies, anterior impingement syndrome, osteochondritis dissecans and meniscoid syndrome. Good to fair results were obtained in osteoarthritis and fibroarthrosis. There were no intra-operative or postoperative complications.

The evaluation of loose bodies in the elbow is usually done by means of clinical examination, radiography, and postarthrographic computed tomography (CT). The authors review their experience with magnetic resonance (MR) imaging in place of post-arthrographic CT for the evaluation of loose bodies in the elbow. The prospective interpretation of MR studies of the elbow in 20 patients was compared with arthroscopic findings. All elbows were imaged in multiple planes with thin sections, surface coils, and combinations of T1, T2, and proton-density weighting. The sensitivity for showing loose bodies with MR imaging was 100%, and the specificity was 67%. Because this was a nonblinded study, the results are biased and caution must be used when extrapolating these results to the general population. In this limited experience, MR imaging has reliably shown loose bodies in the elbow, and in the authors' institutions has replaced postarthrographic CT for that purpose.

13 patients who in childhood had had osteochondral lesions (OCL) of the talar dome participated in a long-term follow-up including physical examination, computed tomography (CT) and conventional radiographs. Most of the cases were caused by trauma. Conventional radiographs showed abnormal findings in 4 cases and CT in a further one. In 3 cases the primary lesion could still be seen as an osteochondral defect, and 2 had a loose body in the joint. 3 of these 5 patients had mild symptoms. We conclude that arthrosis following OCL in childhood is infrequent and recommend conservative treatment initially. In those with persisting symptoms, additional imaging evaluation with CT and MRI is recommended.

Meniscal ossicles are uncommon in humans. They are usually located in the posterior horn of the medial meniscus and are generally first observed on roentgenograms as intraarticular corticated bone densities. Many different entities appear similar to meniscal ossicles on roentgenography. Magnetic resonance imaging (MRI) can help to distinguish between these different entities and thereby assist in guiding treatment. Magnetic resonance imaging also can identify concurrent intraarticular pathology (e.g., meniscal tears), which may influence the choice of treatment. In a 29-year-old man, MRI confirmed the intrameniscal location of a corticated bone density seen in the posteromedial knee on roentgenograms. An associated medial meniscus tear was found at arthroscopy. The patient's symptoms were relieved after resection of the meniscal ossicle and the associated meniscal tear.

Magnetic resonance imaging (MRI) scans were performed on 155 patients who had been placed on a diagnostic knee arthroscopy waiting list 4 to 18 months previously. In all, 32 per cent were removed from the waiting list following this investigation. A total of 24 patients on the waiting list improved spontaneously, including 13 per cent of those with MRI-demonstrable meniscal tears. MRI had an accuracy of 93 per cent, a sensitivity of 100 per cent and a specificity of 67 per cent using arthroscopy as a standard; the false-positive rate was 7 per cent and the false-negative rate 1 per cent. It is concluded that the use of MRI can reduce the requirements for diagnostic arthroscopy, but that the ideal time for MRI is not clear.

Distinguishing between calcific soft-tissue masses and intra-articular loose bodies about the elbow can be difficult. We present the case of a 59-year-old woman with a slowly enlarging soft-tissue mass about the elbow. History, physical examination, and diagnostic studies did not establish a definite diagnosis, nor did they rule out the possibility of a neoplastic process. Excisional biopsy revealed a loose body contained in a cystic mass with elbow joint communication.

Calcified bodies may arise in a joint due to trauma, arthropathy resulting in joint destruction or synovial osteochondromatosis. These calcified loose bodies may pass into a popliteal cyst though posterior joint-bursal communications, or can arise in a popliteal cyst de novo on account of chondrometaplasia. A case history illustrates the differential diagnostic considerations. X-ray combined with ultrasound investigation will exclude soft tissue tumors and vascular lesions.

We studied 13 cases of osteochondritis dissecans of capitellum humeri in 12 children, 11 boys and 1 girl, aged between 10 and 15 years. We distinguished this affection from Panner's disease which affects young children and resembles Legg-Perthes-Calvé disease of the hip. Operative treatment was performed in 7 out of 13 elbows for removal of loose bodies or excision of osteochondritis in situ with cartilage damage. In other cases, functional treatment was carried out. At long-term follow-up, ranging from 2 to 13 years, clinical examination demonstrated satisfactory results in 9 cases; in 3 cases limitation of movement was related to fracture of the radial head or to delay in operative treatment for too long. Roentgenographically, changes related to growth disturbance were constantly observed; they involved the radial head, the olecranon, the trochlea and the proximal end of the ulna.

Localized pigmented villonodular synovitis is a rare condition of the knee that can present with symptoms suggesting internal derangement. We report a case of a patient who presented with signs and symptoms of a loose body in the knee. The lesion was treated with resection using arthroscopic cautery.