RESUMEN
OBJECTIVES: To assess the frequency of anterolateral ligament (ALL) tears and ramp lesions (RL) detected with MRI in patients with anterior cruciate ligament (ACL) tears and to describe associated injuries indicative for these lesions. METHODS: In this retrospective study, 164 patients with surgically verified ACL tears were included. Preoperative MRI scans were reviewed for ALL tears and different types of RL. All coexisting meniscal tears, tears of the medial (MCL) and lateral collateral band (LCL), and posterior-medial tibial bone marrow edema (BME) were recorded. The frequency of ALL tears and RL was assessed and coexisting injuries were correlated using Pearson's chi-square test. A p < 0.05 was defined as statistically significant. In cases of multiple testing, Bonferroni's correction was applied. RESULTS: ALL tears and RL combined were detected in 28 patients (17.1%), ALL tears in 48 patients (29.3%), and RL in 54 patients (32.9%) which were significantly associated to each other. ALL tears were significantly associated with tears of the posterior horn of the lateral meniscus (PHLM), BME, and with tears of the LCL and MCL. RL were significantly associated with tears of the posterior horn of the medial (PHMM) and PHLM, with BME, and with tears of the LCL. CONCLUSIONS: ACL tears are associated with RL or ALL tears in about one-third of cases and with both lesions combined in about one-fifth of cases. ALL tears and RL are significantly associated with additional posttraumatic injuries, which can thus be indicative of these lesions. KEY POINTS: ⢠ACL tears were associated with ramp lesions or ALL tears in about one-third of the cases. ⢠Ramp lesions and ALL tears were significantly associated with each other, tear in the PHLM, tear in the LCL, and BME. ⢠ALL tears were more frequently associated with instable classified ramp lesion type 4b and type 5.
Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Lesiones de Menisco Tibial , Humanos , Lesiones del Ligamento Cruzado Anterior/diagnóstico por imagen , Lesiones del Ligamento Cruzado Anterior/complicaciones , Estudios Retrospectivos , Meniscos Tibiales/patología , Ligamentos , Imagen por Resonancia MagnéticaRESUMEN
Magnesium alloys offer great advantages as degradable implant material for pediatric fracture fixation and hold the potential to overcome certain critical shortcomings inherent to currently used degradable (co)polymers. Besides good biocompatibility and appropriate degradation kinetics, sufficient implant anchorage in host bone is critical to prevent implant failure. Bone-implant anchorage of biodegradable magnesium alloys, however, has not yet been related and compared to that of copolymers, their degradable counterparts currently in clinical use. The aim of this study, therefore, was to comparatively assess bone-implant interface strength and the amount of peri-implant bone of a biodegradable magnesium alloy pin (Mg-Y-Nd-HRE) and a self-reinforced copolymeric control (85/15 poly(l-lactic-co-glycolic acid)). To this purpose, push-out testing, microfocus computed tomography (µCT), histological and scanning electron microscopic examination was performed after 4, 12 and 24 weeks of transcortical implantation in 72 rats. Biomechanical testing revealed significantly higher ultimate shear strength for the magnesium alloy pins than for the copolymeric controls at all 3 timepoints (P≤0.001 for all comparisons). As evaluated by µCT, the amount of bone present near the interface and in a wider radius (up to 0.5mm) around it was higher in the magnesium alloy implants at 4 weeks, without significant differences at 12 and 24 weeks. Histological examination confirmed direct bone-to-implant contact for both implant types. In vivo degradation of implants did not induce any noticeable local or systemic inflammation. This data suggests that the investigated degradable magnesium alloy rod exhibits markedly superior bone-implant interface strength and a greater amount of peri-implant bone than a self-reinforced copolymeric control currently in use; thus it fulfills a crucial prerequisite for its successful clinical deployment as an alternative degradable orthopedic implant material. Further studies, however, are warranted to evaluate the long-term degradation behavior and biocompatibility of the investigated degradable magnesium-based alloy.
Asunto(s)
Clavos Ortopédicos , Fijación Interna de Fracturas/métodos , Magnesio/química , Fenómenos Mecánicos , Oseointegración , Polímeros/química , Microtomografía por Rayos X , Aleaciones , Animales , Materiales Biocompatibles/química , Fenómenos Biomecánicos , Fémur/diagnóstico por imagen , Fémur/lesiones , Fémur/patología , Fémur/cirugía , Magnesio/metabolismo , Masculino , Tamaño de los Órganos , Ratas , Ratas Sprague-DawleyRESUMEN
Previous research on the feasibility of using biodegradable magnesium alloys for bone implant applications mainly focused on biocompatibility and corrosion resistance. However, successful clinical employment of endosseous implants is largely dependent on biological fixation and anchorage in host bone to withstand functional loading. In the present study, we therefore aimed to investigate whether bone-implant interface strength and osseointegration of a novel biodegradable magnesium alloy (Mg-Y-Nd-HRE, based on WE43) is comparable to that of a titanium control (Ti-6Al-7Nb) currently in clinical use. Biomechanical push-out testing, microfocus computed tomography and scanning electron microscopy were performed in 72 Sprague-Dawley rats 4, 12 and 24 weeks after implantation to address this question. Additionally, blood smears were obtained from each rat at sacrifice to detect potential systemic inflammatory reactions. Push-out testing revealed highly significantly greater maximum push-out force, ultimate shear strength and energy absorption to failure in magnesium alloy rods than in titanium controls after each implantation period. Microfocus computed tomography showed significantly higher bone-implant contact and bone volume per tissue volume in magnesium alloy implants as well. Direct bone-implant contact was verified by histological examination. In addition, no systemic inflammatory reactions were observed in any of the animals. We conclude that the tested biodegradable implant is superior to the titanium control with respect to both bone-implant interface strength and osseointegration. These results suggest that the investigated biodegradable magnesium alloy not only achieves enhanced bone response but also excellent interfacial strength and thus fulfils two critical requirements for bone implant applications.
Asunto(s)
Aleaciones/farmacología , Materiales Biocompatibles/farmacología , Huesos/efectos de los fármacos , Huesos/fisiología , Oseointegración/efectos de los fármacos , Titanio/farmacología , Animales , Fenómenos Biomecánicos/efectos de los fármacos , Huesos/citología , Huesos/diagnóstico por imagen , Inmunoensayo , Implantes Experimentales , Interleucina-6/sangre , Microscopía Electrónica de Rastreo , Ratas , Ratas Sprague-Dawley , Microtomografía por Rayos XRESUMEN
BACKGROUND: Fractures of the talus represent serious injuries of the foot skeleton. The most significant complications include osteonecrosis and posttraumatic malalignment with subsequent arthritis. The aim of our study was to compare treatment and outcome of fractures of the talus between children and adolescents. METHODS: From 1990 to 2005, 24 patients (18 male, 6 female) presented with 25 fractures of the talus. The medical records were reviewed retrospectively. Follow-up was performed by radiographical grading, and the functional outcome was measured using the Foot-Function-Index. RESULTS: Nine patients were 12 years of age or younger, and 15 patients presenting 16 talar fractures were older than 12 years. Although most fractures of the talus in children younger than 12 years were classified as Marti-Weber type I and II fractures, more than two thirds of the fractures in patients older than 12 years were Marti-Weber type III and IV fractures. Two thirds of the patients younger than 12 years were treated nonoperatively, whereas nonoperative treatment was possible in only three talar fractures in adolescents. No necrosis at follow-up (mean period, 3.2 years; range, 7 months to 8.4 years after end of treatment) was detected in children (<12a), whereas five patients older than 12 years developed persisting necrosis. CONCLUSION: Even though there is no apparent difference in the cause of the trauma leading to fractures of the talus, adolescents present with more severe fractures of the talus compared with children younger than 12 years. In addition, we did not observe persistent osteonecrosis in patients younger than 12 years old, and the outcome is favorable in most cases irrespective of the mode of treatment.
Asunto(s)
Fracturas Óseas/complicaciones , Astrágalo/lesiones , Adolescente , Artritis/etiología , Niño , Preescolar , Femenino , Fracturas Óseas/patología , Fracturas Óseas/terapia , Humanos , Masculino , Osteonecrosis/etiología , Resultado del TratamientoRESUMEN
Infantile myofibromatosis is a rare benign tumor-disease (1/400,000). Four different types have been reported in literature. The most commonly affected body areas are the head, the neck, and the trunk. We would like to present a rare case of a multicentric type with singular visceral involvement and a literature review of all case series with more than five patients. A 9-month-old boy presented with a swelling on the medial side of his proximal left tibia. The lesion which was present since birth, was well palpable, indolent, hard, and mobile in relation to the surrounding tissue. Radiographic films and ultrasound examination presented a pretibial soft-tissue tumor mass with calcifications and two osteolytic lesions with a sclerotic rim. A skeletal survey showed more osteolytic lesions, but the magnetic resonance imaging showed no more soft-tissue lesions. The rapid frozen section biopsy hinted at the diagnosis of histiocytosis X. The definitive histological result 6 days later was infantile myofibromatosis. As therapy, we determined a wait-and-see policy with controls all 3 months. At 20 months follow-up, the boy showed beginning of regression of all lesions. Infantile myofibromatosis is a very rare benign tumor-disease. Radiologically often soft-tissue masses with calcifications and osteolytic lesions with sclerotic rims are described. These findings also can be interpreted as histiocytosis X, which is a potential differential diagnosis. Histopathologically, cells characteristically appear as spindle-shaped fibroblast cells with pale pink cytoplasm and elongated nuclei and the immunophenotype is defined with a positive reaction on smooth-muscle antigen vimentin and the muscle-specific antigen HHF-35. The data of the literature review underline that a wait-and-see-policy should be considered as the first treatment of choice as in most instances the bony lesions regress spontaneously. However, a thorough examination has to be carried out to exclude lesion in other organs like gastro-intestinal or cardio-pulmonary nodular tumor masses. In conclusion, the present case report and the literature review support the notion that infantile myofibromatosis should be considered as a possible differential diagnosis for soft tissue expansions and/or osteolytic lesions in a newborn.