The objective of this study was to evaluate the suitability of autologous periosteal cells for spinal fusion in humans. Lumbar spondylodesis has a slow consolidation rate with a consecutive lengthy period of inability to work and the risk of non-union. This study evaluates the applicability of a cell-matrix construct for spinal fusion using clinical and radiological parameters.

All experiments were approved by the university ethics committee. Lumbar spondylodesis of the segments L4/5 or L5/S1 was performed in 20 healthy patients (mean age 45 years). Indication for surgery was DDD resistant to conservative treatment. 10 weeks before fusion operation, a piece of periosteum was harvested from the proximal tibia of the patient. The material was chopped and digested. In the washed cell suspension cell number and viability were determined. The viability was greater 90% before seeding. After four passages, the cells were mixed with human fibrinogen, and soaked into polymer fleeces. Polymerization was achieved by adding thrombin. The 3D constructs were cultured for 3 weeks. The final application form were chips of 2mm thickness and 8mm diameter. Spondylodesis was performed using a ventral approach for implantation of 2 titanium cages and a dorsal approach for application of a transpedicular screw-rod system (Medtronic, Sofamor Danek). In 10 patients the chips were implanted ventrally within the cage. The other 10 patients obtained a dorsal intertransverse transplantation of the chips. Pre-operative, 3, 6, 9, and 12 months after surgery a clinical examination was performed, radiographs, and functional scores were obtained.

No implant associated side effects were noted. Especially, signs of infection or allergic reaction have not been observed. The harvest sites of all patients presented symptom-free after 3 months. The rate of consolidation was 60% after 6 months, 90% after 9 months, and 100% after 12 months. No clinical or radiological signs for implant failure or malpositioning were observed. 90% of the patients were satisfied with the outcome of the surgery.

Cultured autologous periosteal cells are a suitable material for anterior as well as posterior spinal fusion in humans. They may accelerate the rate of fusion and reduce the risk of non-union. Rate and velocity of osseous consolidation need to be compared to that of patients treated with iliac crest autograft. A major advantage might be the lower rate of graft site morbidity.

Fracture of the lateral process of the talus (FLPT) is one of the common, yet frequently missed, fractures in snow boarders and can cause severe long-term disability if not treated properly. This fracture has been thought to result from dorsiflexion and inversion combined with axial loading. This assumption is based on injury mechanism reported by patients and anatomical studies and has not been supported by experimental data. We have to understand the mechanism of fracture generation in order to identify potential preventive strategies in equipment design or snowboarding techniques.

In order to understand the pathomechanics of FLPT generation we conducted dynamic impact tests on 19 fresh cadaver lower limbs. A test apparatus was constructed to deliver a pure inversion or eversion moment to the foot and ankle along the centre of rotation of the subtalar joint. An axial load of 2.5 kN was applied to all the legs. The legs were tested in four configurations: inversion with and without dorsiflexion, and eversion with and without dorsiflexion. All the specimens underwent post-test radiographic examination and a necropsy.

Necropsy revealed various injuries including ligamental injuries, malleolar fractures, osteochondral fractures of the talus and joint subluxations. In this study, ten cadaveric leg specimens were subjected to inversion or eversion of an axially loaded and dorsiflexion ankle. Inversion failed to produce any LPT fractures in three injured specimens. However, all six specimens subjected to eversion sustained an LPT fracture. Eversion of an axially loaded and dorsiflexion ankle may be an important injury mechanism for LPT fracture in snowboarders.

Axial loading of the foot/ankle complex is an important injury mechanism in vehicular trauma, responsible for severe injuries such as calcaneus, talus and tibial pilon fractures. Axial loading may be applied to the leg externally, by the toepan and/or pedals, as well as internally by active muscle tension applied through the Achilles tendon during pre-impact bracing. In order to evaluate the effect of active muscle tension on the injury-tolerance of the foot/ankle complex, axial impact tests were performed on isolated lower legs, with and without experimentally stimulated muscle tension applied through the Achilles’ tendon. Acoustic emission was used to determine the exact time of fracture during the tests. The primary fracture mode was calcaneal fracture in both groups, but tibial pilon fractures occurred more frequently with the addition of Achilles tension. A linear regression model was developed that describes the expected axial loading injury tolerance of the foot/ankle complex in terms of specimen age, gender, mass and level of Achilles tension.