Martin Breitenseher

MRI visualization of proteoglycan depletion in articular cartilage via intravenous administration of Gd-DTPA.

The effect of intravenous administration of gadolinium diethylenetriamine-pentaacetic acid (Gd-DTPA) on MR images was studied in vitro, using pathologic osteochondral specimens removed during surgery for total endoprosthesis, and in vivo, on a group of volunteers. In ex vivo specimens, lesions of different shape having lower T1 were detected which corresponded to areas with depleted proteoglycans found histologically. In vivo experiments on young volunteers showed that the time course of cartilage enhancement was different for different anatomies. The time for maximum enhancement ranged from 45 min for the ventral femoral condyle to 270 min for patellar cartilage.

Magnetic resonance imaging of occult scaphoid fractures.

Occult fractures of the scaphoid bone occur frequently and may lead to nonunions. In a prospective blind study, we performed magnetic resonance imaging (MRI) examinations on 32 patients who had sustained a wrist injury and in whom a scaphoid fracture was clinically suspected, but could not be confirmed on the original set of two routine and four scaphoid view radiographs. The MRI examinations were performed an average time of 2.8 days after the trauma. This prospective study proved that MRI is able to diagnose occult scaphoid fractures without delay and without the use of radioactive diagnostic means. Sensitivity and specificity of MRI were 100%. This conventional method could save

Importance of subchondral bone to articular cartilage in health and disease.

7,200 (US) per 100,000 inhabitants in providing an immediate and correct diagnosis and avoiding unnecessary cast immobilization. Additional injuries that may be misdiagnosed by conventional radiographs are also detected with a specificity and sensitivity of 100%.

Rotator cuff tears in asymptomatic individuals: a clinical and ultrasonographic screening study.

The almost absolute barrier to diffusion of nutrients between articular cartilage and subchondral bone does not exist. These anatomic regions represent a functional unit. Repetitive overloading in degenerative disease leads primarily to lesions in the subchondral region (including vessels), which in turn impede flow of nutrition to articular cartilage. As a result, in degenerative joint disease the subchondral region shows reactive enhanced vascularization and heightened metabolism with insufficient repair. In aging, however, vascularization and metabolism are decreased; no repair takes place. In many cases, MRI allows visualization of these subchondral abnormalities. It also demonstrates the basic similarities of degenerative osteoarthritis, osteochondritis dissecans, and avascular necrosis. These different entities may have the same basic etiology but with different disease severity.

Imaging Articular Cartilage Defects with 3d Fat-suppressed Echo Planar Imaging: Comparison with Conventional 3d Fat-suppressed Gradient Echo Sequence and Correlation with Histology

OBJECTIVE To determine the prevalence and clinical impact of rotator cuff tears in asymptomatic volunteers. MATERIALS AND METHODS Sonographic examinations of the shoulder of 212 asymptomatic individuals between 18 and 85 years old were performed by a single experienced operator. The prevalence and location of complete rotator cuff tears were evaluated. The clinical assessment was based on the Constant Score. Magnetic resonance imaging (MRI) of the shoulder was obtained in those patients where US showed rotator cuff pathology. RESULTS Ultrasound showed a complete rupture of the supraspinatus tendon in 6% of 212 patients from 56 to 83 years of age (mean: 67 years). MRI confirmed a complete rupture of the supraspinatus tendon in 90%. All patients reported no functional deficits, although strength was significantly lower in the patient group with complete supraspinatus tendon tear (P < 0.01). CONCLUSION There is a higher prevalence in older individuals of rotator cuff tendon tears that cause no pain or decrease in activities of daily living.

Degenerative joint disease: cartilage or vascular disease?

PURPOSE Our goal was to shorten examination time in articular cartilage imaging by use of a recently developed 3D multishot echo planar imaging (EPI) sequence with fat suppression (FS). We performed comparisons with 3D FS GE sequence using histology as the standard of reference. METHOD Twenty patients with severe gonarthrosis who were scheduled for total knee replacement underwent MRI prior to surgery. Hyaline cartilage was imaged with a 3D FS EPI and a 3D FS GE sequence. Signal intensities of articular structures were measured, and contrast-to-noise (C/N) ratios were calculated. Each knee was subdivided into 10 cartilage surfaces. From a total of 188 (3D EPI sequence) and 198 (3D GE sequence) cartilage surfaces, 73 and 79 histologic specimens could be obtained and analyzed. MR grading of cartilage lesions on both sequences was based on a five grade classification scheme and compared with histologic grading. RESULTS The 3D FS EPI sequence provided a high C/N ratio between cartilage and subchondral bone similar to that of the 3D FS GE sequence. The C/N ratio between cartilage and effusion was significantly lower on the 3D EPI sequence due to higher signal intensity of fluid. MR grading of cartilage abnormalities using 3D FS EPI and 3D GE sequence correlated well with histologic grading. 3D FS EPI sequence agreed within one grade in 69 of 73 (94.5%) histologically proven cartilage lesions and 3D FS GE sequence agreed within one grade in 76 of 79 (96.2%) lesions. The gradings were identical in 38 of 73 (52.1%) and in 46 of 79 (58.3%) cases, respectively. The difference between the sensitivities was statistically not significant. CONCLUSION The 3D FS EPI sequence is comparable with the 3D FS GE sequence in the noninvasive evaluation of advanced cartilage abnormalities but reduces scan time by a factor of 4.

Die „transiente Osteoporose“ als reversible Sonderform der Hüftkopfnekrose

Abstract The aetiology of degenerative joint diseases is multifactorial, but one main cause is overloading (mechanical stress). While until recently it was well accepted that this represented primarily a disorder of cartilage with reactive subchondral changes, there is now some evidence that it might be primarily a subchondral problem with secondary changes in the articular cartilage. Early subchondral changes include redistribution of blood supply with marrow hypertension, oedema and probably micro-necrosis. These findings are very similar to those in avascular necrosis of bone and raise the question of a vascular aetiology. While these first reports need further proof, it seems clear that the articular cartilage and subchondral regions are one functional unit, in which the subchondral region is more stress sensitive. Recently described channels connecting these two regions strengthen this opinion. These new concepts are exciting and may make a major impact in the near future on the management of and research into degenerative joint disease.

Mason type-I radial head fractures and interosseous membrane lesions--a prospective study.

ZusammenfassungEs wird bis heute kontrovers diskutiert, ob die „transiente Osteoporose“ des Hüftgelenks ein eigenständiges, selbstlimitierendes Krankheitsbild, oder eine reversible Sonderform der Osteonekrose (ON) darstellt. Die „transiente Osteoporose“ ist auch unter den Synonymen „Algodystrophie der Hüfte“, „transient marrow edema“ oder „Knochenmarködemsyndrom (KMÖS)“ bekannt. Das klinische Erscheinungsbild besteht aus mechanischen Hüftgelenkschmerzen, ON-Risikofaktoren und einem diffusen Knochenmarködem in der MRT. Die histomorphologischen Veränderungen entsprechen den Frühformen einer ON. Während jedoch das KMÖS einen suffizienten diffusen Reparaturmechanismus zeigt, erfolgt bei der ON nur eine insuffiziente fokale Reparatur in der Randzone der Nekrose. Der klinische Verlauf ist daher völlig unterschiedlich. Während das KMÖS in fast allen Fällen einen reversiblen Spontanverlauf zeigt, kommt es umgekehrt bei der ON ab dem Stadium II zu einer progredienten Zerstörung des Hüftkopfes. Das bevorzugte Behandlungskonzept ist daher die konservative Therapie mit Entlastung für das KMÖS und die operative Therapie für die ON. In einer prospektiven Studie von 43 Hüftgelenken bei Patienten mit KMÖS wurde der klinische, röntgenologische und MRT Verlauf nach Hüftkopfentlastungsbohrung untersucht. Alle Patienten zeigten eine spontane Schmerzerleichterung unmittelbar nach der Entlastungsbohrung und die durchschnittliche Beschwerdedauer von 6 (3–24) Monaten bei konservativer Therapie konnte mit der Entlastungsbohrung auf durchschnittlich 2 Monate reduziert werden. Perioperativ traten keine Komplikationen auf. Basierend auf unseren Erfahrungen mit inzwischen über 100 Patienten mit KMÖS sind wir überzeugt, dass es sich hierbei nicht um ein selbständiges Krankheitsbild sondern vielmehr um eine reversible Sonderform einer ON handelt. Aufgrund der ausgezeichneten klinischen Ergebnisse mit der Hüftkopfentlastungsbohrung empfehlen wir diese operative Behandlungsmethode beim schmerzhaften KMÖS des Hüftgelenks.SummaryThere is still controversy whether transient osteoporosis of the hip joint represents a distinct self-limiting disease, or reflects only an early, reversible subtype of non-traumatic osteonecrosis (ON). Transient osteoporosis has several synonyms: algodystrophy of the hip; transient marrow oedema; or bone marrow oedema syndrome – BMOES. Clinical presentation of BMOES shows mechanical hip joint pain, ON risk factors, and a diffuse bone marrow oedema in MR imaging. Histomorphological changes resemble early ON, but with diffuse sufficient repair in BMOES and focal and insufficient repair only at the border of the necrotic lesion in ON. Therefore the clinical course and outcome are significant different, with restitution occurring in BMOES, while progressive destruction of the joint takes place in ON. So far, the preferred treatment strategies are protected weight bearing for BMOES, but operative treatment for ON. In a prospective study of patients with BMOES, the clinical, radiographic, and MRI course of 43 hip joints after core decompression treatment were investigated. All patients showed immediate relief of pain after surgery and the average duration of symptoms with conservative treatment could be dramatically reduced by core decompression from 6 months down to 2 months. There were no perioperative complications. Based on our experience with over 100 BMOES patients , we are convinced that this syndrome represents not a distinct disease but an early reversible subtype of non-traumatic ON. Due to the excellent clinical results of core decompression, we recommend this operative therapeutical concept in patients with painful BMOES.

MRI versus lateral stress radiography in acute lateral ankle ligament injuries

BACKGROUND The role of the forearm interosseous membrane (IOM) in trauma remains not fully understood. Information from experimental models simulating sudden axial loading of the IOM is limited. The results from several cadaver studies are controversially discussed in literature. Pronation and supination of the forearm as well as varus and valgus position of the elbow joint have been suspected to have influence on the injury pattern. The purpose of the current study, therefore, was to further investigate the role of the IOM in trauma mechanism. METHODS We prospectively screened the forearms of 14 patients with Mason type-I radial head fractures for additional occult IOM lesions. The fractures were classified according to the Mason classification using plain radiographs. All patients were subjected to forearm magnetic resonance imaging visualizing the entire IOM within a week. Treatment consisted of nearly total immobilization of the elbow joint using a special elastic and gauze bandage for 7 days followed by an early motion recovery program. RESULTS Partial disruptions of the distal part of the IOM were found in nine cases. The biomechanically essential interosseous ligament was not attained by these ruptures in any of the cases. None of the patient had the classical findings of the Essex Lopresti lesion. All patients had regular roentgenograms of both wrists. Patients were asymptomatic at the time of a 4-week follow-up. CONCLUSION Our results suggest that injuries of the IOM are more frequent than generally expected. The findings support the conclusions of some of the previous cadaver studies. If IOM lesions are suspected, magnetic resonance imaging tomography should be performed.

Imaging of avascular necrosis of bone

PURPOSE Our goal was to compare the abilities of MRI and stress radiography to detect the extent of recent lateral ankle ligament inversion injuries. METHOD In this prospective study, 60 athletically active patients (aged 18-45 years) with recent inversion trauma (< or = 7 days) underwent stress radiography and MRI. In 15 patients, the MR findings were reviewed at surgery. Patients were divided into three groups according to severity of ligament injury on MRI (no, one, or two to three ligament tears). Based on bilateral stress radiography, patients were classified into three groups according to the differential degree of talar tilt (< or = 5, 6-14, or > or = 15 degrees) and compared with patients from the MR groups. RESULTS Surgery showed MRI to have 74% sensitivity and 100% specificity in the evaluation of complete lateral ankle ligament tears. Agreement between MR and stress radiography groups for the severity of recent lateral ankle ligament tears was poor (kappa = 0.030). CONCLUSION MRI should be performed in young, athletically active patients if surgical intervention is contemplated, especially at 6-14 degrees talar tilt on stress radiography, since stress radiography tends to over- and underestimate the severity of lateral ligament trauma.