Robert D. Wissman

Acute knee dislocation: review of an elusive entity.

The knee consists of three articulations: the patellofemoral, the tibiofemoral, and the proximal tibiofibular joint. Any of these joints can dislocate. Dislocations are uncommon, tend to spontaneously reduce, and can be difficult to detect on clinical examination. There are, however, telltale imaging features and the radiologist may be the first to suggest the correct diagnosis. A timely diagnosis is important as some forms are associated with limb-threatening complications. Lateral patellofemoral dislocation, in the acute setting, is typically an injury of young athletes and usually spontaneously reduces at the time of trauma. In transient lateral dislocation, contusions may be seen in the inferomedial pole of the patella and the anterior lateral aspect of the nonarticular portion of the femur. The important magnetic resonance imaging findings include this characteristic contusion pattern and injury to the medial patellar soft-tissue restraints. These are frequently associated with osteochondral fractures, which may be an indication for surgery. Recurrent patellofemoral dislocations tend to be associated with abnormalities of bony and/or soft-tissue restraints. The important imaging considerations are the length of patellar tendon, the depth of trochlear groove, and the position of patella in relation to the trochlear groove. Tibiofemoral dislocations are rare and are usually associated with high-impact trauma. These are multi-ligamentous injuries, which most often involve both cruciate ligaments with either medial and/or lateral ligament tears. There is an associated risk of popliteal artery and peroneal nerve injury, even if reduced, at the time of presentation. Dislocations of the tibiofibular joint are also rare and are classified based on location of fibular head. The tibiofibular joint is lax in flexion, and thus, most dislocations tend to occur in the flexed knee position. Anterolateral dislocation is the most common, while posteromedial dislocation is frequently associated with peroneal nerve injury. The purpose of this article is to review the epidemiology of knee dislocations, important imaging findings, and the most common complications.

Percutaneous balloon humeroplasty for Hill-Sachs lesions: a novel technique

INTRODUCTION Hills-Sachs lesions are commonly associated with anterior shoulder dislocations and can be a source of recurrent instability. Studies have shown that, even after soft tissue repair of a Bankart lesion, there is still a risk for redislocation in a patient with significant bony defects. The purpose of this study is to ascertain whether balloon humeroplasty is an effective technique of reducing acute Hill-Sachs defect in a cadaveric model. METHODS Eighteen cadaveric humerii dissected free of soft tissue were used for this study. Hill-Sachs lesions were created in a reproducible manner in the anatomical posterolateral aspect of the head with a mallet edge. An inflatable balloon tamp (balloon, IBT) was used to reduce the lesion via a small transcortical window. Cement was used to fill the void created by the balloon. We utilized computed tomography (CT) to collect volume data of each humeral head pre- and post-procedure. From this data, we calculated the volume of the Hill-Sachs defect and the percent corrected. A paired t test was performed to analyze the data statistically. RESULTS The average prereduction Hill-Sachs defect volume was 1515.5 mm(3). The average post-reduction lesion residual volume was 31 mm(3) with 99.3% reduction to the original humeral head volume. The Hill-Sachs lesion reduction was statistically significant with P value of .0004. CONCLUSION Balloon humeroplasty proved to be an effective technique for reducing Hill-Sachs lesions in a cadaveric model. This technique may be used as an adjunct to arthroscopic versus open Bankart procedure for engaging acute Hill-Sachs lesions.

Cysts Within and Adjacent to the Lesser Tuberosity and Their Association With Rotator Cuff Abnormalities

OBJECTIVE The purpose of our study was to determine the incidence of cysts in and adjacent to the lesser tuberosity and their association with rotator cuff abnormalities and subcoracoid impingement. MATERIALS AND METHODS A retrospective review of 1,000 consecutive MRI examinations of the shoulder was performed by consensus of two radiologists. Cysts were grouped by location into one of two groups: those within the lesser tuberosity and those adjacent to the lesser tuberosity. The rotator cuff was defined as intact, partial tear or tendinosis, or full-thickness tear. The shortest distance from the coracoid to the humeral head was measured on axial images. RESULTS Forty-eight patients (26 women, 22 men; age range, 35-79 years; mean age, 61 years) had cysts adjacent to or within the lesser tuberosity. Thirty-two patients (67%) had cysts just superior to the tuberosity and 16 (33%) had cysts in the lesser tuberosity, resulting in an incidence of 3.2% and 1.6%, respectively. All 16 patients (100%) with lesser tuberosity cysts had subscapularis and supraspinatus tendon abnormalities including 11 (69%) full-thickness supraspinatus tears. Patients with cysts superior to the tuberosity had 20 (63%, p = 0.004) abnormal subscapularis tendons and 28 (88%) abnormal supraspinatus tendons, including six (19%) full-thickness tears (p = 0.002). The coracohumeral distance was noted to be less than 10 mm in 10 patients (63%) with lesser tuberosity cysts as compared with 10 patients (31%, p = 0.06) with cysts superior to the tuberosity. CONCLUSION Cysts located within the lesser tuberosity are rare and are indicative of subscapularis and supraspinatus tendon abnormalities.

The next accreditation system in radiology: A report from the APDR residency structure committee

In a move to emphasize the educational outcomes of training programs, the ACGME has created the Next Accreditation System (NAS). The stated goals of NAS include aiding the ACGME in the accreditation of programs based on educational outcome measures, decreasing program burdens associated with the conventional process-based approach to ACGME accreditation, allowing good programs to innovate while enabling struggling programs to steadily improve, and providing public accountability for outcomes. Diagnostic radiology is among the first group of specialties to undergo NAS implementation and began operating under the NAS in July 2013. This article describes the various components of the NAS and explains the new elements, including the clinical learning environment review program, the milestones, the clinical competency committee, and the self-study visits.

The Role of Imaging in Diagnosing Diseases of the Distal Radioulnar Joint, Triangular Fibrocartilage Complex, and Distal Ulna

OBJECTIVE The purpose of this article is to review the anatomy, biomechanics, and multimodality imaging findings of common and uncommon distal radioulnar joint (DRUJ), triangular fibrocartilage complex, and distal ulna abnormalities. CONCLUSION The DRUJ is a common site for acute and chronic injuries and is frequently imaged to evaluate chronic wrist pain, forearm dysfunction, and traumatic forearm injury. Given the complex anatomy of the wrist, the radiologist plays a vital role in the diagnosis of wrist pain and dysfunction.

Lead poisoning from a gunshot wound.

Lead poisoning from gunshot wounds is unusual. Awareness of this rare but serious complication can guide the physician in making a prompt diagnosis. We present a case of a 30-year-old male who had a remote history of a gunshot wound in the right knee and presented with right knee pain. Plain film showed intrarticular invasion of the bullet fragments. He was also found to have microcytic anemia with high blood lead levels. Chelation therapy was immediately started, followed with surgical removal of the bullet fragments. Lead intoxication is a rare but fatal complication of gunshot wounds. After a timely diagnosis, chelation therapy should be immediately started.

Multiple intraosseous lipomatosis: a case report.

IntroductionIntraosseous lipoma is an uncommon entity that presents almost exclusively as a solitary lesion. Multiple intraosseous lipomas are exceedingly rare with only a few cases being reported in the literature.Case presentationWe present a case of 43-year-old African American female who presented with left leg and left wrist pain. The initial radiographs revealed well-defined radiolucent lesions in multiple bones involving the left wrist and the left lower limb. The magnetic resonance demonstrated multiple lesions, which showed high signal on the T1 and low signal on the fat suppressed T2 images. This favored the diagnosis of intraosseous lipomatosis that was confirmed by biopsy.ConclusionMultiple intraosseous lipomatosis is an uncommon but important differential for multiple radiolucent lesions on the plain radiographs. This condition can lead to pathological fractures. Magnetic resonance imaging can aid in providing an accurate diagnosis. The awareness of this condition can help the clinician in guiding the correct diagnosis and management.

Case 165: Oncogenic Osteomalacia

Oncogenic osteomalacia is an acquired paraneoplastic syndrome caused by secretion of fibroblast growth factor 23, often resulting in severe bone pain at presentation and a high frequency of fractures.

Extensor Mechanism Injuries in Tibiofemoral Dislocations

The purpose of this study is to evaluate the incidence, location, and associated findings of extensor mechanism injuries in the setting of tibiofemoral knee dislocations. Methods: A retrospective search for patients with previous knee dislocation and MRI of the knee was made during a 5-year period. Images were evaluated for abnormalities commonly seen in patellar instability. Patellar and quadriceps tendon integrity were also evaluated. Results: A total of 14 patients were included in the study. Medial patellofemoral ligament injuries were identified in 10 patients (71%) with tibiofemoral dislocation. As in patients with previous patellar dislocation, medial patellofemoral ligament injuries commonly occurred at the femoral attachment of the ligament. Medial patellofemoral ligament injuries correlated well with vastus medialis oblique elevation. Patellar tendon injuries were less common identified in only 5 patients (36%). Conclusions: Medial patellofemoral ligament injuries can be associated with tibiofemoral knee dislocations. In addition, patellar tendon injuries can also occur, although these are usually partial tears.

Acute Concomitant Anterior Cruciate Ligament and Patellar Tendon Tears in a Non-dislocated Knee

Anterior cruciate ligament (ACL) tears are common and may occur in isolation or with other internal derangements of the joint. Tears of the patellar tendon (PT) occur less frequently and are rarely associated with intra-articular pathology. Acute combined tears of both the ACL and PT are known complications of high-energy traumatic knee dislocations. We present a case of an acute concomitant ACL and PT tears in a low-energy non-dislocated knee. To our knowledge, this injury has only been described in a limited number of case reports in the orthopedic literature. We present the imaging findings of this combined injury and discuss the importance of magnetic resonance (MR) in diagnosis.