A prospective nonrandomized study was made of 17 basketball players with fractures of the proximal third of the shaft of the fifth metatarsal. Eight had acute fractures, which were treated with a cast without weight-bearing, and the other nine had stress fractures for which percutaneous compression screwing was initially used. In the first group, union was obtained in four cases in an average of 9 weeks, with resumption of sport by 12 weeks. Three had a good outcome and the fourth was fair. The other four cases, which had not healed after 12 weeks of immobilization, were subsequently treated using compression screws. Resumption of sport was achieved 20-24 weeks after the fracture. Two of these had a good result; in the other two the results were fair. Of the nine patients with stress fractures in which a screw was inserted, all healed between 8 and 14 weeks and returned to sport within 7-12 weeks. Seven had a good result and the other two only fair. There was one intraoperative complication, but no postoperative complications, such as nonunion or refracture, were observed. Even if the non-operative treatment is able to provide a good result, immobilization without weight-bearing does not guarantee healing. In this series, percutaneous screw fixation was able to achieve successful healing in a short period of time. Thus, this procedure seems to be preferable for primary treatment of this lesion in athletes.

No abstract

The application of porous materials is increasingly being used in orthopaedic surgery due to its good results. Bone growth within the pores results in excellent mechanical fixation with the bone, as well as good bone regeneration. The pores, in addition to being colonised by bone, produce a decrease in the modulus of elasticity that favours the transfer of loads to the bone. This research shows the results of an experimental study where we have created critical osteoperiosteal defects of 10 mm on rabbit’s radius diaphysis. In one group of 10 rabbits (experimental group) we have implanted a bioactive porous titanium cylinder, and in another group we have allowed spontaneous regeneration (control group). Mechanical tests were performed to assess the material. Image diagnostic techniques (X-ray, scanner and 3D scan: there are no references on the literature with the use of CT-scan in bone defects) and histological and histomorphometric studies post-op and after 3, 6 and 12 months after the surgery were performed. All the control cases went through a pseudoarthrosis. In 9 of the 10 cases of the experimental group complete regeneration was observed, with a normal cortical-marrow structure established at 6 months, similar to normal bone. Titanium trabecular reached a bone percentage of bone inside the implant of 49.3% on its surface 3 months post-op, 75.6% at 6 months and 81.3% at 12 months. This porous titanium biomaterial has appropriate characteristics to allow bone ingrowth, and it can be proposed as a bone graft substitute to regenerate bone defects, as a scaffold, or as a coating to achieve implant osteointegration.

Conceptos biomecánicos de los clavos «en cerrojo» Biomechanical properties of «keyhole» nails Resumen Se pasa revista a las propiedades mecánicas comparativas de los diferentes montajes alcanzables con los distintos modelos y concepciones de clavos «en cerrojo*. Es evidente que la rigidez y resistencia de los clavos macizos y después de los clavos huecos de sección cerrada es superior a los clavos convencionales o de primera generación. Igualmente el bloqueo por tornillos o pernos sobre cortical es mejor que el proporcionado por aletas u otros artilugios a nivel de la esponjosa. No cabe duda que los clavos «en cerrojo)) suponen un gran avance y ventaja en el tratamiento de las fracturas complejas de la extremidad inferior.

Constrained liners are a salvage procedure for treating or preventing recurrent dislocations. The Longevity® constrained liner (Zimmer) has a special design with cut-outs on its circumference for avoiding impingement in certain areas and a metallic constraining ring that has to be impacted. The ring impaction may be technical demanding. We recommend preassembly with the head component prior to seating into the acetabular cup, thus avoiding the soft tissue or cement interference and malposition due to bad angle of incidence of impaction force.