The syndesmosis ligament complex stabilizes the distal tibiofibular joint, while allowing for the subtle fibular motion that is essential for ankle congruity. Flexible fixation with anatomic syndesmosis reduction results in substantial improvements in functional outcomes. New dynamic CT technology allows real-time imaging, as the ankle moves through a range of motion. The aim of this study was to determine if dynamic CT analysis is a feasible method for evaluating syndesmosis reduction and motion following static and flexible syndesmosis fixation. This is a subgroup analysis of a larger multicenter randomized clinical trial, in which patients with AO 44-C injuries were randomized to either Tightrope (one knotless Tightrope, Group T) or screw fixation (two 3.5-mm cortical screws, Group S). Surgical techniques and rehabilitation were standardized. Bilateral ankle CT scans were performed at one year post-injury, while patients moved from maximal dorsiflexion (DF) to maximal plantar flexion (PF). Three measurements were taken at one cm proximal to the ankle joint line in maximal DF and maximal PF: anterior, midpoint, and posterior tibiofibular distances. T-tests compared Group T and Group S, and injured and uninjured ankles in each group. Fifteen patients (six Group T [three male], nine Group S [eight male]) were included. There was no difference for mean age (T = 42.8 ± 14.1 years, S = 37 ± 12.6, P = 0.4) or time between injury and CT scan (T = 13 ± 1.8 months, S = 13.2 ± 1.8, P = 0.8). Of note in Group S, seven of nine patients had at least one broken screw and one additional patient had screws removed by the time of their dynamic CT. There was no significant difference between treatment groups for tibiofibular distance measurements in maximal PF or DF. Group T showed no significant difference between the injured and uninjured side for tibiofibular measurements in maximal PF and DF, suggesting anatomic reduction. For Group S, however, there was a significantly larger distance for all three measurements at maximal PF compared to the uninjured ankle (all P < 0 .05). In all but one Group S patient, screws were broken or removed prior to their dynamic CT, allowing possible increased syndesmotic motion, similar to Group T. Despite this, dynamic CT analysis detected increased tibiofibular distance in Group S as ankles moved into maximal PF when compared with the uninjured ankle. Given the importance of anatomic syndesmosis reduction, dynamic ankle CT technology may provide valuable physiologic information warranting further investigation

Traditional screw fixation of the syndesmosis can be prone to malreduction. Suture button fixation however, has recently shown potential in securing the fibula back into the incisura even with intentional malreduction. Yet, if there is sufficient motion to aid reduction, the question arises of whether or not this construct is stable enough to maintain reduction under loaded conditions. To date, there have been no studies assessing the optimal biomechanical tension of these constructs. The purpose of this study was to assess optimal tensioning of suture button fixation and its ability to maintain reduction under loaded conditions using a novel stress CT model. Ten cadaveric lower limbs disarticulated at the knee were used. The limbs were placed in a modified external fixator frame that allows for the application of sustained torsional (5 Nm), axial (500 N) and combined torsional/axial (5Nm/500N) loads. Baseline CT scans of the intact ankle under unloaded and loaded conditions were obtaining. The syndesmosis and the deltoid ligament complex were then sectioned. The limbs were then randomised to receive a suture button construct tightened at 4 kg force (loose), 8 kg (standard), or 12 kg (maximal) of tension and CT scans under loaded and unloaded conditions were again obtained. Eight previously described measurements were taken from axial slices 10 mm above the tibiotalar joint to assess the joint morphology under the intact and repair states, and the three loading conditions: a measure of posterolateral translation (a, b), medial/lateral translation (c, g), a measure of anterior-posterior translation (f), a ratio of anterior-posterior translation (d/e), an angle (Angle 1) created by a line parallel to the incisura and the axis of the fibula, and an angle (Angle 2) created between the medial surfaces of two malleoli. These measurements have all been previously described. Each measurement was taken at baseline and compared with the three loading scenarios. A repeated measures ANOVA with a Bonferroni correction for multiple comparisons was used to test for significance. Significant lateral (g, maximum 5.26 mm), posterior (f, maximum 6.42 mm), and external rotation (angle 2, maximum 11.71°) was noted with the 4 kg repair when compared to the intact, loaded state. Significant posterior translation was also seen with the both the 8 kg and 12 kg repairs, however the incidence and magnitude was less than with the 4 kg repair. Significant overcompression (g, 1.69 mm) was noted with the 12 kg repair. Suture button constructs must be appropriately tensioned to maintain reduction and re-approximate the degree of physiological motion at the distal tibiofibular joint. If inserted too loosely, these constructs allow for supraphysiologic motion which may have negative implications on ligament healing. These constructs also demonstrate overcompression of the syndesmosis when inserted at maximal tension however the clinical effect of this remains to be determined

Ankle sprains have been shown to be the most common sports related injury. Ankle sprain may be classified into low ankle sprain or high ankle sprain. Low ankle sprain is a result of lateral ligament disruption. It accounts for approximately 25% of all sports related injuries. The ankle lateral ligament complex consists of three important structures, namely the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL) and posterior talofibular ligament (PTFL). The ATFL is the weakest and most easily injured of these ligaments. It is often described as a thickening of the anterolateral ankle capsule. The ATFL sits in a vertical alignment when the ankle is plantarflexed and thus is the main stabiliser against an inversion stress. T he CFL is extracapsular and spans both the tibiotalar and talocalcaneal joints. The CFL is vertical when the ankle is dorsiflexed. An isolated injury to the CFL is uncommon. Early diagnosis, functional management and rehabilitation are the keys to preventing chronic ankle instability following a lateral ligament injury. Surgery does not play a major role in the management of acute ligament ruptures. Despite this up to 20% of patients will develop chronic instability and pain with activities of daily living and sport especially on uneven terrain. Anatomic reconstruction for this group of patients is associated with 90% good to excellent results. It is important that surgery is followed by functional rehabilitation. One of the aims of surgery in patients with recurrent instability is to prevent the development of ankle arthritis. It should be noted that the results of surgical reconstruction are less predictable in patients with greater than 10 year history of instability. Careful assessment of the patient with chronic instability is required to exclude other associated conditions such as cavovarus deformity or generalised ligamentous laxity as these conditions would need to be addressed in order to obtain a successful outcome. High ankle sprain is the result of injury to the syndesmotic ligaments. The distal tibiofibular joint is comprised of the tibia and fibula, which are connected by anterior inferior tibiofibular ligament, interosseous ligament and the posterior inferior tibiofibular ligament (superficial and deep components). The mechanism of injury is external rotation and hyperdorsiflexion. High index of suspicion is required as syndesmotic injuries can occur in association of low ankle sprains. The clinical tests used in diagnosing syndesmotic injuries (external rotation, squeeze, fibular translation and cotton) do not have a high predictive value. It is important to exclude a high fibular fracture. Plain radiographs are required. If the radiograph is normal then MRI scan is highly accurate in detecting the syndesmotic disruption. Functional rehabilitation is required in patients with stable injuries. Syndesmotic injuries are often associated with a prolonged recovery time. Accurate reduction and operative stabilisation is associated with the best functional outcome in patients with an unstable syndesmotic injury. Stabilisation has traditionally been with screw fixation. Suture button syndesmosis fixation is an alternative. Early short-term reviews show this alternate technique has improved patient outcomes and faster rehabilitation without the need for implant removal

Ten patients, who were unsuitable for limb lengthening over an intramedullary nail, underwent lengthening with a submuscular locking plate. Their mean age at operation was 18.5 years (11 to 40). After fixing a locking plate submuscularly on the proximal segment, an external fixator was applied to lengthen the bone after corticotomy. Lengthening was at 1 mm/day and on reaching the target length, three or four screws were placed in the plate in the distal segment and the external fixator was removed. All patients achieved the pre-operative target length at a mean of 4.0 cm (3.2 to 5.5). The mean duration of external fixation was 61.6 days (45 to 113) and the mean external fixation index was 15.1 days/cm (13.2 to 20.5), which was less than one-third of the mean healing index (48 days/cm (41.3 to 55). There were only minor complications.

Lengthening with a submuscular locking plate can successfully permit early removal of the fixator with fewer complications and is a useful alternative in children or when nailing is difficult.

We report the results of using a combination of fixator-assisted nailing with lengthening over an intramedullary nail in patients with tibial deformity and shortening. Between 1997 and 2007, 13 tibiae in nine patients with a mean age of 25.4 years (17 to 34) were treated with a unilateral external fixator for acute correction of deformity, followed by lengthening over an intramedullary nail with a circular external fixator applied at the same operating session. At the end of the distraction period locking screws were inserted through the intramedullary nail and the external fixator was removed.

The mean amount of lengthening was 5.9 cm (2 to 8). The mean time of external fixation was 90 days (38 to 265). The mean external fixation index was 15.8 days/cm (8.9 to 33.1) and the mean bone healing index was 38 days/cm (30 to 60).

One patient developed an equinus deformity which responded to stretching and bracing. Another developed a drop foot due to a compartment syndrome, which was treated by fasciotomy. It recovered in three months. Two patients required bone grafting for poor callus formation.

We conclude that the combination of fixator-assisted nailing with lengthening over an intramedullary nail can reduce the overall external fixation time and prevent fractures and deformity of the regenerated bone.