Background: The number of total ankle replacements has been raising in the last years. Most publications present short- and medium-term results. Comparison of outcomes is difficult because of inconsistent terminology and different parameters used. Moreover, poorly performing implants cannot be identified quickly because of low numbers, delayed reporting or publication bias.

Methods: Therefore, we have developed a module for total ankle prostheses in the framework of the International Documentation and Evaluation System (IDES) for standardized and centralized documentation of TAA outcomes. Content validation was conducted with a single surgeon series of 74 HINTEGRA_ ankle replacements.

Results: Between March 2004 and February 2008 74 patients were treated. The preoperative diagnosis was 18.9% osteoarthritis, 32.4% rheumatoid arthritis, 43.3% posttraumatic, 1.4% osteonecrosis and 4% others. There were intraoperative complications in 4%, local postoperative complications in 17.6% and revision surgeries in 16.2% of patients. The AOFAS hind-foot score improved from 23.8 points preoperative to 75.3 points after a mean followup time of 8.4 months. No significant differences in outcome were revealed between the various diagnostic groups.

Conclusion: The IDES-forms facilitate a structured and standardized data collection that is feasible in a research orientated but also purely clinical setting; this because of the different extents to which data can be recorded. The consistent use of the system assures a stringent internal quality assurance, and more interesting, an external quality assurance by means of comparisons and benchmarking with other users feeding the data pool with the exact same variables and outcomes. The Hintegra ankle appeared as a safe device with low complication rates in the hands of a foot and ankle specialist. A surgical learning curve was seen in the first two years.

Background: The Evans osteotomy has been proven to be very effective in treating flatfoot deformity in adults. However, it has not been shown whether the site of osteotomy influences the contact areas and peak pressures within the subtalar joint. It is hypothesized that the posterior facet of the calcaneus rotates posteriorly and laterally resulting in altered contact characteristics and peak pressures in the subtalar joint.

Materiala and Methods: We used a finite-element model (FEA) of the hindfoot. Computed tomography slides of patients who suffered from adult flatfoot deformity were prepared by means of open-source software and converted into a three-dimensional model of the hindfoot. The FEA model allows the virtual performance of an osteoteomy and simulates force transmissions through the hindfoot and calculates joint contact characteristics and peak pressure alterations as well. Two different kind of osteotomies were tested:

an osteotomy 10mm proximal to the calcaneocuboid joint line and

Results: There were small but significant differences found between osteotomies done either close to the calcaneocuboid joint or directly adjacent to the posterior facet. At both sites the posterior calcaneal facet rotated posteriorly and laterally. However we found a significant decreases in contact areas and raises in peak pressures within the subtalar joint in cases where the osteotomy was performed close to the posterior calcaneal facet.

Summary: This study presents the effects of virtual Evans osteotomies on the subtalar joint and their dependence upon the site of the osteotomies.

Background: Calcaneonavicular coalitions (CNC) have been reported to be associated with anatomical aberrations of either the calcaneus and/or navicular bones. These morphological abnormalities may complicate accurate surgical resection. Three-dimensional analysis of spatial orientation and morphological characteristics may help in preoperative planning of resection.

Materials and Methods: Sixteen feet diagnosed with CNC were evaluated by means of 3D CT modeling. Three angles were defined that were expressed in relation to one reproducible landmark (lateral border of the calcaneus): the dorsoplantar inclination, anteroposterior inclination and socket angle. The contact surface area was determined from the depth and width of the coalitions. Three-dimensional reconstructions of the calcanei evaluated the presence and morphology of the anterior calcaneal facet and of a navicular beak. The inter-observer correlations were assessed for the accuracy of the measurement methods. Sixteen normal feet were used as controls for comparison of the socket angle and anatomy of the anterior calcaneal facet and of the navicular beak.

Results: The dorsoplantar inclination angle averaged 50° (±17), the anteroposterior inclination angle 64° (±15), and the pathologic socket angle 98° (±11). The average contact area was 156mm2. Ninety-four percent of all patients in the CNC group revealed a plantar navicular beak. In 50% of those patients the anterior calcaneal facet was replaced by the navicular portion and in 44% the facet was totally missing. In contrast, the socket angle in the control group averaged 77° (± 18), which was found to be statistically different than the CNC group (p=0.0004). Only 25% of the patients in the control group had a plantar navicular beak. Statistically significant inter-observer correlations were found for all measured angles.

Conclusions: Computer aided CT analysis and reconstructions help to determine the spatial orientations of CNC and provide useful information in order to anticipate morphological abnormalities of the calcaneus and navicular.

Purpose of the study: Chronic lateral instability of the ankle is often associated with residual varus deformity of the rear foot and exaggerated plantar flexion of the first ray. Several surgical techniques have been described to treat this problem, but recurrence can occur if all the components of the instability are not corrected. The purpose oft his work was to present was to present a new diagnostic and therapeutic approach to the treatment of recurrent lateral instability of the ankle.

Material and methods: Eight patients with talipes cavovarus(9 feet) were treated for recurrent chronic instability of the ankle. All patients had undergone at least one prior procedure to stabilize the rear foot and suffered persistent pain as well as subjective ankle instability. Mean age was 25 years. All patients underwent a calcaneal osteotomy for lateralization and transfer of the long fibular onto the short fibular ligament, with an additional Bronström ligament reconstruction in four cases. Clinical and radiological follow-up was 37 months on average.

Results: All patients were very satisfied. The AOFAS score improved from 58 points preoperatively to 97 points (max 100 points) at last follow-up. Postoperative alignment of the rear foot was considered physiological in all cases.

Conclusion: Recurrent chronic lateral instability of the ankle is often associated with chronic misalignment of the rear foot, leading to gait disorders and persistent pain. Ligament insufficiency, varus misalignment, and over-solicitation of the long fibular should be investigated and treated with an individually adapted surgical procedure in order to correct the recurrent instability. The results of this approach have been very promising and have been associated with very strong patient satisfaction.