Lumbosacral nerve root avulsions: MR imaging demonstration of acute abnormalities

Most of the previously reported lumbosacral nerve root avulsions presented with pseudomeningoceles at the time of delayed initial imaging. We report a case of traumatic lumbosacral nerve root injury associated with an isolated femur fracture and demonstrate the evolution of pseudomeningoceles following nerve root avulsions and edema in the perineural fat identified on the initial MR imaging.

Entrapment of the acetabular labrum following reduction of traumatic hip dislocation in a child

In traumatic hip dislocation, concentric reduction can be prevented by various causes. Soft-tissue interposition, such as entrapment of the acetabular labrum, is a rare but important cause of failed reduction of a hip. Early diagnosis of incomplete reduction due to interposition of soft tissue is important, because delayed treatment is associated with a greater incidence of avascular necrosis of the femoral head and early onset of osteoarthritis. This report describes a case of acetabular labral entrapment following reduction of traumatic hip dislocation in a child. The importance of CT and MRI in arriving at an early diagnosis is emphasized.

MDCT of tendon abnormalities using volume-rendered images

OBJECTIVE

Our objectives were to report tendon abnormalities diagnosed on 3D volume-rendered images from MDCT data and to validate the clinical usefulness of this technique.

CONCLUSION

We present 18 tendon abnormalities from 16 patients that were diagnosed on 3D volume-rendered MDCT images generated by commercially available software. Certain abnormalities such as avulsions, partial tears, and dislocations of tendons are clearly shown by this technique. This technique may prove useful in the evaluation of tendon abnormalities when MRI or sonography cannot be used.

T1-weighted MR imaging for distinguishing large osteolysis of Paget's disease from sarcomatous degeneration

OBJECTIVE

To report five symptomatic patients, four with unequivocal Paget's disease and large areas of osteolysis and one patient with presumed osteolytic Paget's disease, evaluated by MR imaging to confirm or exclude a sarcoma.

DESIGN AND PATIENTS

Four men and one woman (median age 74 years) presented with new symptoms of pain. Four of these patients had unequivocal Paget's disease with large areas of osteolysis; one patient presented with large focal osteolysis and no other finding. MR imaging was performed in each case to exclude malignancy in the area of osteolysis.

RESULTS

Two patients whose MR images showed a low signal abnormality on the T1-weighted sequence corresponding to osteolysis on the radiograph were found to have malignant degeneration. Three patients with osteolytic lesions on T1-weighted MR imaging showed preservation of fat signal in the areas of osteolysis, were not biopsied and have been free of malignant disease for from 12 months to 2 1/2 years. One patient had one area of osteolysis in the iliac bone which showed malignancy and another area of osteolysis which showed preservation of fat signal on the T1-weighted sequence.

CONCLUSIONS

The information obtained from T1-weighted MR imaging sequences performed on patients with Paget's disease who have new symptoms and large areas of osteolysis could reliably be used in the clinical decision-making process between conservative follow-up and biopsy.

Focal fibrocartilaginous dysplasia: curettage as an alternative to conservative management or more radical surgery

We describe two cases of focal fibrocartilaginous dysplasia, one treated conservatively while the other underwent curettage of the lesion. Resolution of tibia vara and healing of the focal fibrocartilaginous dysplasia was noted at 6 months in the patient who underwent curettage while the conservatively managed patient required 8 years of follow-up. Of the 17 cases of conservatively followed tibial focal fibrocartilaginous dysplasia described in the literature, 11 showed complete recovery after a median interval of 57 months. We believe that curettage may result in rapid healing by removing the persistent mesenchymal anlage which can interfere with the normal growth of the tibia.

Atypical calcific tendinitis with cortical erosions

OBJECTIVE

To present and discuss six cases of calcific tendinitis in atypical locations (one at the insertion of the pectoralis major and five at the insertion of the gluteus maximus).

PATIENTS AND RESULTS

All cases were associated with cortical erosions, and five had soft tissue calcifications. The initial presentation was confusing and the patients were suspected of having infection or neoplastic disease.

CONCLUSION

Calcific tendinitis is a self-limiting condition. It is important to recognize the imaging features of this condition to avoid unnecessary investigation and surgery.

Contribution of individual projections alone and in combination for radiographic detection of ankle fractures

OBJECTIVE

We wanted to determine whether the standard three-view ankle radiographic series could be replaced by a two-view combination, and if so, which two-view combination (anteroposterior with lateral or mortise with lateral) would be superior.

MATERIALS AND METHODS

During a 12-month period, we retrospectively reviewed 556 consecutive ankle radiographic studies consisting of anteroposterior, mortise, and lateral views. One hundred twenty patients with at least one ankle fracture were paired with 140 healthy control subjects. Each image in the three-view examination was separated and sorted by view and studied independently; all images were reviewed by two skeletal radiologists and two orthopedic surgeons. Each radiograph was evaluated for fracture of the medial, lateral, and posterior malleoli and the foot using a five-point confidence rating. Performance of each view and modeled two- and three-view combinations of views was evaluated with modified receiver operating characteristic analysis.

RESULTS

The data provide little support for preferring either two-view combination (anteroposterior-lateral or mortise-lateral) for any type of fracture. The three-view combination does detect significantly more fractures than some two-view combinations in some locations, and there is a statistically significant cost in diagnostic accuracy for eliminating the anteroposterior or mortise view.

CONCLUSION

Reducing the ankle radiographic series from three to two views would result in a small but significant decrease in the detection of fractures of the ankle and foot. Both two-view combinations are equivalent for fracture detection.

Imaging features of avulsion injuries

Avulsion injuries are common among participants in organized sports, especially among adolescent participants. Imaging features of both acute and chronic avulsion injuries of the pelvis, knee, ankle and foot, shoulder, and elbow were evaluated to help distinguish these injuries from more serious disease processes such as neoplasm and infection. At radiography, acute injuries (ie, those resulting from extreme, unbalanced, often eccentric muscular contractions) may be associated with avulsed bone fragments, whereas subacute injuries have an aggressive appearance that may include areas of mixed lysis and sclerosis. Chronic injuries (ie, those resulting from repetitive microtrauma or overuse) or old inactive injuries may be associated with a protuberant mass of bone and may bear a striking resemblance to a neoplastic or infectious process. Although not usually required, computed tomography is helpful in the diagnosis if radiographic findings are equivocal or if the injury is not in the acute phase. MR imaging is best suited for the evaluation of injuries to muscles, tendons, and ligaments. Recognition of characteristic imaging features and familiarity with musculotendinous anatomy will aid in accurate diagnosis of avulsion injuries.

Case report: paraarticular soft-tissue osteoma of the hip

A case of paraarticular soft-tissue osteoma of the hip is presented. The patient is a 30-year-old white male with a two year history of progressive left hip pain. Plain film and cross-sectional imaging in conjunction with pathologic correlation are used to make the diagnosis. The lesion lacks the typical zoning pattern of myositis ossificans, shows no direct communication with native bone, and is extraarticular in location as opposed to synovial osteochondromatosis. Soft tissue osteomas most commonly occur around the knee, the foot, and the ankle. Soft tissue osteomas are rare tumors and this case is unusual in that it occurs around the hip.

Subchondral metastasis: report of five cases

Subchondral metastasis is a rare occurrence and poses a diagnostic dilemma as initial films may show a lytic lesion in the subchondral region often misinterpreted as being benign. We present five cases of subchondral metastasis as well as a review of the literature. In our cases, we present subchondral metastasis in the elbow, shoulder, and hip joints. All patients had pain over the affected joint and most presented with a lytic lesion in the subchondral bone. Three patients have died since presentation and two are doing well at last follow up visit. Subchondral metastasis is a rare entity, but it should be included in the differential of a lytic lesion in the subchondral bone.

Elastofibroma dorsi: prevalence in an elderly patient population as revealed by CT

OBJECTIVE

We wanted to determine the prevalence and appearance of elastofibroma dorsi in an elderly patient population (n = 258) who underwent CT of the chest for reasons other than to evaluate posterolateral chest wall pain, stiffness, or a mass.

CONCLUSION

Five elastofibromas were detected in four patients; none of these elastofibromas were noted at initial examination. Our study suggests that the prevalence of elastofibroma dorsi revealed by CT is 2%, which is lower than the 11-24% found in autopsy series but higher than expected for such a rare tumor. Elastofibroma dorsi typically has a layered appearance on CT; however, in our study, homogeneous soft-tissue attenuation was noted. The diagnosis is often missed prospectively. Familiarity with the location and imaging appearance of elastofibroma dorsi may enhance detection and characterization of posterolateral chest wall masses in elderly patients.

Modified technique for fluid aspiration from the hip in patients with prosthetic hips

A modified technique was used for diagnostic aspiration of fluid from the hip in 185 patients who had previously undergone total hip arthroplasty. The aspiration needle was advanced past the lateral aspect of the shaft of the prosthesis and into the dependent portion of the joint. Fluid was successfully aspirated in 181 of 185 patients; thus the dry-tap rate was 2.2% (four of 185 patients). The modified technique was simple, could be performed quickly, and was effective for sampling joint fluid in patients with hip prostheses.

MRI of complete rupture of the pectoralis major muscle

Rupture of the pectoralis major muscle is a rare clinical entity. Only few reports have discussed its MRI or CT features. We have reviewed the imaging features of four cases of complete rupture of the pectoralis major muscle. One case of acute injury underwent surgical repair. MRI is useful in delineating the site and extent of the rupture in relation to the musculotendinous junction, which will help the surgeons with possible treatment options and surgical planning. Because of the complex anatomy of the pectoralis major muscle near its insertion on the humerus and the signal characteristics of hematoma and edema in the muscle, axial T2-weighted images were most valuable for the evaluation of acute and subacute injuries. Axial T1-weighted images were helpful in delineating chronic injuries. CT is inferior to MRI for direct visualization of muscle rupture.

Seronegative spondyloarthropathies

The seronegative spondylarthropathies are a group of multisystem inflammatory disorders that share a variety of clinical, radiologic, and genetic features. They include ankylosing spondylitis, psoriatic arthritis, Reiter's disease, and arthritis associated with inflammatory bowel disease. This article reviews these multisystem inflammatory disorders.

Imaging of muscle injuries

Although skeletal muscle is the single largest tissue in the body, there is little written about it in the radiologic literature. Indirect muscle injuries, also called strains or tears, are common in athletics, and knowing the morphology and physiology of the muscle-tendon unit is the key to the understanding of these injuries. Eccentric muscle activation produces more tension within the muscle than when it is activated concentrically, making it more susceptible to tearing. Injuries involving the muscle belly tend to occur near the myotendinous junction. In adolescents, the weakest link in the muscle-tendon-bone complex is the apophysis. Traditionally, plain radiography has been the main diagnostic modality for evaluation of these injuries; however, with the advent of MRI it has become much easier to diagnose injuries primarily affecting the soft tissues. This article reviews the anatomy and physiology of the muscle-tendon unit as they relate to indirect muscle injuries. Examples of common muscle injuries are illustrated.

Posterior atlantooccipital subluxation in Down syndrome

Three Down syndrome patients with posterior atlantooccipital (AO) subluxation are described. All are asymptomatic. The subluxation becomes manifest during active extension of the neck and reduces in flexion. Methods of assessing posterior AO subluxation are discussed. The abnormality is attributed to ligamentous laxity in patients with Down syndrome.

Arthrotomography of the wrist. The palmar radiocarpal ligaments

Twenty-one fresh cadaver wrists were studied by arthrography and arthrotomography. Arthrography was unreliable in accurately delineating the palmar radiocarpal ligaments. However, lateral arthrotomograms predictively and precisely outlined the radiolucent radiocapitate and radiotriquetral ligaments. The radial and more distant radiolucent area was the radiocapitate ligament, and the ulnar and more proximal area was the radiotriquetral ligament. A constant radiopaque invagination between the outlines of contrast material demonstrated the sulcus anatomically separating these two ligaments. When the ligaments were transected contrast material entered the substance of the ligaments, rendering them radiopaque and, thus, visible on the radiographs. The authors believe that arthrotomography may be a useful clinical tool in the evaluation of post-traumatic injuries to the palmar radiocarpal ligaments of the wrist.

Meniscotibial (coronary) ligament tears

Preservation of the meniscus whenever possible is essential in maintaining knee stability and preventing premature osteoarthritis. Peripheral meniscal tears are the most amenable to surgical repair. This study evaluates the peripheral attachments of the medial meniscus and focuses on a specific tear limited to the meniscotibial ligament (coronary ligament). The diagnosis is made arthrographically when the medial meniscus floats above the tibial plateau without separating completely from the capsule. The lateral meniscus is rarely involved in this type of injury.

Fine-needle aspiration biopsy of bone

The technique of fine-needle aspiration biopsy seems to be ideally suited for the diagnosis of lytic bone lesions at practically any location in the skeleton. The technique is simple, carries minimum risks, and can often be performed on an outpatient basis. Advances in cytological techniques have made it possible to reach an accurate diagnosis for most patients within twenty-four hours. The accuracy rate in the present study of seventy patients was 87.5 per cent, but the lesions studied included few primary bone tumors. One limitation of the technique is the difficulty in sampling a lesion that is covered by compact bone.

Arthrotomography of the wrist. The triangular fibrocartilage complex

Eighteen fresh cadaver wrists were radiographically studied using both arthrography and arthrotomography, to evaluate the results of the two techniques. With arthrography, communications between the distal radioulnar and radiocarpal joints were discovered in eight of the 18 wrists (44%). Although defects in the triangular fibrocartilage complex (TFCC) could be inferred from the arthrograms, the locations and dimensions of the defects could not be assessed satisfactorily. Using arthrotomography, three distinct patterns of TFCC defects were observed radiographically, which correlated with subsequent anatomic dissections of the cadaver specimens. Type I defects, located near the radial margin of the TFCC, are long, narrow posteroanterior fissures with thick regular borders that readily appose. Type II defects, located more centrally in the TFCC, are wide defects with thin irregular margins. Type III defects represent a communication between the prestyloid recess and the distal radioulnar joint. Arthrotomography of the wrist accurately delineates TFCC defects in cadaveric specimens and may become a valuable clinical radiographic procedure.

Normal sagittal diameter and variation in the pediatric cervical spine

The sagittal diameter of the cervical spinal canal is traditionally evaluated when an expansile intraspinal lesion is suspected. Some workers have concluded that the normal sagittal diameter gradually decreases from C1 to C7 in some people, while in others it decreases from C1 to C3 and remains nearly constant from C4 to C7. The authors' study of 158 young individuals with no evidence of cervical cord lesions showed that gradual widening of the lower canal and even ballooning of the mid-canal are frequently seen in normal children 10 years old or younger, and occasionally in persons up to 18 years of age. The mechanism by which the canal attains a funnel-shaped appearance in adults is discussed.

Subtalar dislocation

Over a period of three years we have seen nine patients with subtalar dislocation, all of whom sustained violent trauma to the region of the ankle and hind foot. All but one patient were males. Clinically a subtalar dislocation resembles a complicated fracture dislocation of the ankle but a definitive diagnosis can only be made radiographically. The mechanism of injury and radiographic features of this injury are discussed.

Congenital aplastic-hypoplastic lumbar pedicle in infants and young children

Nine cases of congenital aplastic-hypoplastic lumbar pedicle (mean age 27 months) are described. Their data are compared to those of 18 other reported cases (mean age 24.7 years)and the following conclusions are made: (1) Almost exclusively, the pedicular defect in infants and young children is due to developmental anomaly rather than destruction by malignancy or infectious processes. (2) This anomaly, we think, is more common than it is believed to be. (3) Unlike adults, infants and young children rarely develop hypertrophy and/or sclerosis of the contralateral pedicle. (4) Detection of pedicular anomaly is more than satisfying a radiographic curiosity and may lead to discovery of other coexisting anomalies. (5) Ultrasonic screening of the patients with congenital pedicular defects may detect the associated genitourinary anomalies, if present, and justify further studies in a selected group of patients.

A radiographic study of skeletal deformities in treated clubfeet

Thirty-two patients with treated unilateral clubfoot deformity were followed for a period of 13 to 30 years. The functional results were satisfactory in 28 feet. A comparison of the skeletal features of the normal and the clubfeet was made on roentgenographs. Many clubfeet had small, slightly flattened talar heads, decreased talocalcaneal angles, undersized or misshapen facets of the subtalar joint, and medially displaced navicular. The residual deformity of the hindfoot was compensated by the lateral displacement and lateral angulation of the cuneiforms with respect to the navicular resulting in a normal alignment of the forefoot in relation to the hindfoot. The range of ankle dorsiflexion, subtalar and midtarsal joint motion was restricted in the clubfeet.

Stress fractures of the femoral neck: a scintigraphic sign for early diagnosis

Two patients with hip pain are presented; both patients were on steroid therapy. The diagnosis of a stress fracture was initially missed because the patients were not exceedingly active and the plain roentgenograms were essentially normal. The bone scan demonstrated a discretely localized area of increased radionuclide uptake in the femoral neck, which alerted us to the correct diagnosis. This scintigraphic sign is helpful in arriving at an early diagnosis and preventing prolonged disability.

The fallen fragment sign in unicameral bone cyst

The roentgenographic findings in unicameral bone cyst may be difficult to differentiate from a solid tumor of bone. When present, the fallen fragment sign may aid in determining the roentgenographic diagnosis of unicameral bone cyst. In this finding, with a pathologic fracture a fragment of cortical bone may become dislodged and gravitate to the dependent portion of the unicameral bone cyst. Two examples of the fallen fragment sign demonstrate the displacement of a fragment of cortical bone to the dependent portion of the cystic cavity.

Gas and metrizamide myelography in abnormalities of the craniovertebral junction

Ten symptomatic patients with skeletal abnormalities of varying etiology at the craniovertebral junction were studied with gas or metrizamide myelography. The type of compressive pathology was accurately delineated by these techniques. The surgical approach was determined by the findings on the myelograms.

Cranial settling in rheumatoid arthritis

Cranial settling occurs in about 5-8% of patients with rheumatoid arthritis, sometimes resulting in severe neurological problems or even death. It is caused by collapse of the supporting structures at the craniovertebral junction, mainly the lateral masses of C1. Twelve cases are presented; 2 patients with severe neurological problems were treated surgically.

A new radiographic technique utilizing multidirectional tomography with double contrast arthrography for studying the glenoidal labrum

The glenoid labrum is an important anatomical structure in the shoulder. Its function and pathophysiology of labral tears are discussed. Detailed description of a new radiographic technique to visualize the labrum utilizing arthrotomography is presented.

Neuropathic fractures in patients with diabetes mellitus

Six patients with diabetes mellitus sustained neuropathic fractures. All had depressed or absent pain sensation in their legs. Four patients had unusual avulsion fractures in the posterior tubercle of the calcaneus. One had sustained six fractures within a period of six months. In 4 patients the fractures were followed by or associated with neuroarthropathy. The incidence and etiology of such fractures are discussed.

Radionuclide bone image in growing and stable bone island

A normal radionuclide bone image can facilitate distinction between a bone island and significant pathologic processes, especially an osteoblastic metastasis. This distinction becomes more crucial when growth is detected in an isolated sclerotic bone lesion or if a relatively large sclerotic lesion is detected de novo in patients with a known neoplasm. This report presents three patients with isolated bone islands: two with interval growth, the other with a relatively large stable lesion; all showing a normal radionuclide bone image.

Symptomatic bursa formation with osteochondromas

Two cases of bursa formation in association with osteochondromas are presented. This condition may be confused radiographically and clinically with malignant transformation of the cartilage cap. Ultrasound examination on one of the patients proved helpful in arriving at the correct preoperative diagnosis. Ultrasonography was also helpful to the surgeon with regard to size and extent of the bursa.

Arthrotomography of the glenoid labrum

Arthrotomography was used to study the glenoid labrum in 8 patients with problems of shoulder instability. In 4 patients, an anterior lesion of the labrum was noted radiographically. The abnormality was confirmed at surgery in 3 of the 4. In 1 of the 3, anterior capsular detachment was also demonstrated radiographically and confirmed surgically. One patient had voluntary posterior subluxation: radiographically, the labrum was normal, and at surgery no abnormalities could be found. The technique, which is simple to perform is described and radiographic anatomy discussed.