Bone shape variability within a specific population has been seldom investigated and used to optimize implant design. There is insufficient anatomical fitting of the existing prebend periarticular plates for the distal fibula. We developed a methodology for design of orthopaedic implants that fit a maximum percentage of the target population, both in terms of geometry and biomechanical stability. In co-operation with an implant manufacturer and different academic institutions, a virtual bone database has been developed that contains anatomical data of more than 1000 CT datasets with the implemented possibility to generate idealized implant fits for different anatomical sites. This program (Stryker Virtual Bone Database (VBD) is able to generate statistical anatomical shapes for different populations like age groups or ethnical groups. Based on this, an implant for the distal fibula has been developed (VariAx Distal Lateral Fibula Locking Plate) for distal fibula fracture treatment. Aim of this study was to develop and validate an implant that is optimized for the specific anatomical area. It should be precontoured and still fit to the majority of patients sustaining a distal fibular fracture. Another objective was to create a distally tapered design as there is less soft tissue cover in that anatomic area. Materials & Methods. ProE CAD system was used in combination with the Bone Database (VBDB) to evaluate the bone shape of the target population plate shape. Several bones (from CT scans) have been used in a first validation process in comparison with an implant already available on the market (SPS Fibula Plate). Additionally, the results have been verified with a bone fitting study which was conducted in collaboration with the Maurice E. Müller Institute (MEM) in Bern/Switzerland. In a second step, the finished implant design was validated against statistical bone shapes of populations of different ethical origin. Results. The comparison of the new Plate's shape with real bone data confirmed that the neutral form does cope with the anatomic situation laterally which means that no systematic pre-bending of the plate is required. Comparing with a conventional implant, the new implant could have been implanted unbend in 6 of 7 cases of virtual matching with real patient datasets compared to none with the conventional implant. The validation of statistical datasets of different ethnical origin (Caucasian, Asian) showed no statistical difference of implant mismatch. Conclusion. Based on these results, the new Plate can be considered an efficient solution to treat distal fibula fractures without or only limited time consuming intra-operative bending. Although technically now possible, different plate designs for Caucasians and Asians are not required

Assessment of stability in ankle fractures is key in deciding the most appropriate mode of treatment. Stress radiographs have been suggested as a potential method for assessing ankle stability in patients with apparently isolated lateral malleolar fractures. Whilst stress radiographs have been found to be both sensitive and specific in cadaveric experiments, recent clinical studies have suggested that a widened medial clear space (MCS) on stress radiographs may not equate to a functionally unstable ankle. We aimed to assess whether patients with an apparently isolated lateral malleolar fracture on presentation but with a positive gravity stress radiograph (GSR) could be successfully managed non-operatively. A prospective study of all patients with lateral malleolar fractures presenting to our orthopaedic trauma department was undertaken. Patients with an oblique distal fibular fracture pattern and no obvious MCS widening on routine radiographs underwent a GSR. Measurements of the radiographic MCS and superior clear space (SCS) were made and compared with published criteria. 155 patients were included in the study and treated non-operatively fully weight bearing in either a cast or removable boot. Following fracture union all patients had both anatomical alignment of the ankle mortise and good or excellent function. The MCS of 79% of these patients was found to be greater than 4 mm with 19% greater than 6 mm. All of these patients were successfully managed non-operatively. The currently used criteria for measurements on stress radiographs result in high numbers of false positive cases. This may be leading to unnecessary surgery. Further investigation is required in order to identify other clinical or radiographic criteria that may be of use in the assessment of functional ankle stability after fracture

Our aim was to compare the one-year post-operative outcomes following retention or removal of syndesmotic screws in adult patients with a fracture of the ankle that was treated surgically. A total of 51 patients (35 males, 16 females), with a mean age of 33.5 years (16 to 62), undergoing fibular osteosynthesis and syndesmotic screw fixation, were randomly allocated to retention of the syndesmotic screw or removal at three months post-operatively. The two groups were comparable at baseline.

One year post-operatively, there was no significant difference in the mean Olerud–Molander ankle score (82.4 retention vs 86.7 removal, p = 0.367), the mean American Orthopedic Foot and Ankle Society ankle-hindfoot score (88.6 vs 90.1, p = 0.688), the mean American Academy of Orthopedic Surgeons foot and ankle score (96.3 vs 94.0, p = 0.250), the mean visual analogue pain score (1.0 vs 0.7, p = 0.237), the mean active dorsiflexion (10.2° vs 13.0°, p = 0.194) and plantar flexion (33.6° vs 31.3°, p = 0.503) of the ankle, or the mean radiological tibiofibular clear space (5.0 mm vs 5.3 mm, p = 0.276) between the two groups. A total of 19 patients (76%) in the retention group had a loose and/or broken screw one year post-operatively.

We conclude that removal of a syndesmotic screw produces no significant functional, clinical or radiological benefit in adult patients who are treated surgically for a fracture of the ankle.

Cite this article: Bone Joint J 2014;96-B:1699–1705.

Using human cadaver specimens, we investigated the role of supplementary fibular plating in the treatment of distal tibial fractures using an intramedullary nail. Fibular plating is thought to improve stability in these situations, but has been reported to have increased soft-tissue complications and to impair union of the fracture. We proposed that multidirectional locking screws provide adequate stability, making additional fibular plating unnecessary. A distal tibiofibular osteotomy model performed on matched fresh-frozen lower limb specimens was stabilised with reamed nails using conventional biplanar distal locking (CDL) or multidirectional distal locking (MDL) options with and without fibular plating. Rotational stiffness was assessed under a constant axial force of 150 N and a superimposed torque of ± 5 Nm. Total movement, and neutral zone and fracture gap movement were analysed.

In the CDL group, fibular plating improved stiffness at the tibial fracture site, albeit to a small degree (p = 0.013). In the MDL group additional fibular plating did not increase the stiffness. The MDL nail without fibular plating was significantly more stable than the CDL nail with an additional fibular plate (p = 0.008).

These findings suggest that additional fibular plating does not improve stability if a multidirectional distal locking intramedullary nail is used, and is therefore unnecessary if not needed to aid reduction.

Cite this article: Bone Joint J 2014;96-B:385–9.

Filling the empty holes in peri-articular locking plates may improve the fatigue strength of the fixation. The purpose of this in vitro study was to investigate the effect of plugging the unused holes on the fatigue life of peri-articular distal femoral plates used to fix a comminuted supracondylar fracture model.

A locking/compression plate was applied to 33 synthetic femurs and then a 6 cm metaphyseal defect was created (AO Type 33-A3). The specimens were then divided into three groups: unplugged, plugged with locking screw only and fully plugged holes. They were then tested using a stepwise or run-out fatigue protocol, each applying cyclic physiological multiaxial loads.

All specimens in the stepwise group failed at the 770 N load level. The mean number of cycles to failure for the stepwise specimen was 25 500 cycles (sd 1500), 28 800 cycles (sd 6300), and 26 400 cycles (sd 2300) cycles for the unplugged, screw only and fully plugged configurations, respectively (p = 0.16). The mean number of cycles to failure for the run-out specimens was 42 800 cycles (sd 10 700), 36 000 cycles (sd 7200), and 36 600 cycles (sd 10 000) for the unplugged, screw only and fully plugged configurations, respectively (p = 0.50). There were also no differences in axial or torsional stiffness between the constructs. The failures were through the screw holes at the level of comminution.

In conclusion, filling the empty combination locking/compression holes in peri-articular distal femur locking plates at the level of supracondylar comminution does not increase the fatigue life of the fixation in a comminuted supracondylar femoral fracture model (AO 33-A3) with a 6 cm gap.