Introduction. The dichotomy between surgical repair and conservative management of acute Achilles tendon ruptures has been eliminated through appropriate functional management. The orthoses used within functional management however, remains variable. Functional treatment works on the premise that the ankle/hindfoot is positioned in sufficient equinus to allow for early weight-bearing on a ‘shortened’ Achilles tendon. Our aim in this study was to test if 2 common walking orthoses achieved a satisfactory equinus position of the hindfoot. Methods. 10 sequentially treated patients with 11 Achilles tendon injuries were assigned either a fixed angle walking boot with wedges (FAWW) or an adjustable external equinus corrected vacuum brace system (EEB). Weight bearing lateral radiographs were obtained in plaster and the orthosis, which were subsequently analysed using a Carestream PACS system. The Mann-Whitney test was used to compare means. Results. Initial radiographs of all patients in cast immobilization showed a mean tibio-talar angle (TTA) of 55.67° (SD1.21) and a mean 1. st. metatarsal-tibia angle (1MTA) of 73.83° (SD9.45). There were 6 Achilles tendons treated in the FAWW. Their measurements showed a mean TTA of 27.67°(SD7.71) and 1MTA 37.00 (5.22). 5 tendons were treated using an EEB; there was a statistically significant (p< .05) increase in both the TTA 47.6° (SD5.90) and 1MTA 53.67 (SD5.77) compared to the FAWW group. Discussion. Plantar-flexion at the ankle was significantly greater in the EEB comparative to the FAWW, and very similar to the initial equinus cast. The use of wedges produced an equinus appearance through the midfoot, without producing equinus in the hindfoot as the heel pad rests on the top wedge. We express caution in the use of wedges for Achilles treatment as they do not shorten the Achilles tendon and may result in a lengthened tendon and reduced plantar-flexion power in the long-term

Introduction. Survival rates of recent total ankle replacement (TAR) designs are lower than those of other arthroplasty prostheses. Loosening is the primary indication for TAR revisions [NJR, 2014], leading to a complex arthrodesis often involving both the talocrural and subtalar joints. Loosening is often attributed to early implant micromotion, which impedes osseointegration at the bone-implant interface, thereby hampering fixation [Soballe, 1993]. Micromotion of TAR prostheses has been assessed to evaluate the stability of the bone-implant interface by means of biomechanical testing [McInnes et al., 2014]. The aim of this study was to utilise computational modelling to complement the existing data by providing a detailed model of micromotion at the bone-implant interface for a range of popular implant designs, and investigate the effects of implant misalignment during surgery. Methods. The geometry of the tibial and talar components of three TAR designs widely used in Europe (BOX®, Mobility® and SALTO®; NJR, 2014) was reverse-engineered, and models of the tibia and talus were generated from CT data. Virtual implantations were performed and verified by a surgeon specialised in ankle surgery. In addition to the aligned case, misalignment was simulated by positioning the talar components in 5° of dorsi- or plantar-flexion, and the tibial components in ± 5° and 10° varus/valgus and 5° and 10° dorsiflexion; tibial dorsiflexed misalignement was combined with 5° posterior gap to simulate this misalignment case. Finite element models were then developed to explore bone-implant micromotion and loads occurring in the bone in the implant vicinity. Results. Micromotion and bone loads peaked at the end of the stance phase for both the tibial and talar components. The aligned BOX and SALTO demonstrated lower tibial micromotion (with under 30% of bone-implant interface area subjected to micromotion larger than 100µm, as opposed to > 55% for Mobility; Figure 1). Talar micromotion was considerably lower for all designs, and no aligned talar component demonstrated micromotion larger than 100µm. The aligned SALTO showed the largest talar micromotion (Figure 2). Dorsiflexed implantation of all tibial components increased micromotion and bone strains compared to the reference case; interestingly, the SALTO tibial component, which demonstrated the lowest micromotion for the aligned case, also demonstrated the smallest changes in micromotion due to malpositioning (Figure 3). The posterior gap between the tibia and implant further increased bone strains. Dorsi- or plantar-flexed implantation of all talar components considerably increased micromotion and bone loads compared to the reference case (Figure 2), often resulting in micromotion exceeding 100µm. The SALTO talar component demonstrated the smallest changes in micromotion due to malpositioning. Discussion. The aligned Mobility had greater tibial micromotion than the SALTO and BOX, which agrees with higher revision rates reported in registry data (e.g. NZJR, 2014). The increased micromotion associated with dorsi- or plantar-flexion misalignment highlights the importance of aligning the implant correctly, and implies that SALTO can be more “forgiving” for malpositioning than the other TAR designs. Implant design and alignment are therefore important factors that affect the implant fixation and performance of the reconstructed ankle

Introduction. Osteochondral autologous autograft (also called mosaic arthroplasty) is the preferred treatment method for very large osteochondral defects in the ankle. For long-term success of this procedure, the transplanted plugs should reconstruct the curvature of the articular surface. The different curvatures between femoral-patella joint and the dome of the talus makes the reconstruction difficult and requires lots of experience. Material. Prior to the surgery a CT arthrogram of the ankle, as well as a CT of the knee were obtained and 3D bone models for the knee, the ankle as well as a model for the ankle cartilage were created. Using custom-made software a set of osteochondral grafts (“plugs”) positioned over the defect site were planned and an optimal harvest location for each plug was chosen. Intraoperatively, an optoelectronic navigation system was installed and sensors were attached to femur, talus, and conventional harvest and delivery chisels. A combined pair-point and surface matching was performed to register femur and talus. For each planned plug the surgeon positioned, oriented, and rotated the harvest and delivery chisels with respect to preoperative plan by using the visual and numerical feedback of the system. Results. We performed the above described procedure on a 37 year old female patient with osteochondral injury of the dome of the right talus with an approximate size of 20mm × 9mm. One 8mm and two 6mm plugs were planned and intraoperative navigated. At 6 months postoperative she had a significant improvement in her passive range of motion from 0–15° dorsi-flexion and 0–60° plantar-flexion, compared to her uninjured ankle of 0–15° dorsi-flexion and 0–80° plantar-flexion. The inversion and eversion of the ankle are normal and x-ray evaluation showed good and complete integration of the osteochrondal plugs. Discussion. A virtual preoperative planning tool helped to solve the complex geometrical problem of reconstructing the articular cartilage surface of the talus using multiple autologous osteochondral plugs from the knee. The intraoperative optoelectronic guidance allowed the surgeon to transfer this plan into the intraoperative situation

Background: There is abundant literature on the treatment of Achilles tendon rupture; however data on sports and recreational activities after this injury is scarce. Patients and Methods: 71 patients were assessed in a prospective cross-sectional study after an average of 3 years after Achilles tendon rupture. 44 patients were treated non-operatively, using a functional algorithm, and 23 patients were treated operatively. Outcome parameters were the AOFAS-Score and the SF-36 Score. The strength of plantar-flexion was measured using the Isomed 2000 system, the structural integrity of the tendon was assessed sonografically. Results: Patients treated operatively had a higher complication rate than patients treated non-operatively (p=0.05). Re-rupture rate was identically in both groups. No difference was noted between the two groups for the AOFAS score (92 vs. 90). Moreover the SF-36 score did not show any significant difference between the groups. However, if compared to the age-adjusted normative population significant lower scores were achieved. A significant reduction in practicing sports was detected, as well as a reduction of plantar flexion of the affected foot (p=0.04). Conclusion: Except for complication rate no significant difference could be detected between the groups. Thus operative treatment in the recreational athletes should only be considered, if no adaptation of the ends of the tendon is diagnosed during the initial or repeated ultrasound. Regardless of the therapeutic intervention chosen an Achilles tendon rupture leads to marked changes in sports- and recreational activities

A new design of total ankle replacement was developed. According to extensive prior research, the design features a spherical convex tibial component, a talar component with radius of curvature in the sagittal plane longer than that of the natural talus, and a meniscal component fully conforming to these two. The shapes of the tibial and talar components are compatible with a physiologic ankle mobility and with the natural role of the ligaments. Within an eight-centre clinical trial, 114 patients were implanted in the period July 2003 – September 2006, with mean age 62.2 years (range 29 – 82). The AOFAS clinical score systems and standard radiographic assessment were used to assess patient outcome, here reported only for those 75 patients with follow-up longer than 6 months. Intra-operatively, the components maintained complete congruence at the two articulating surfaces of the meniscal bearing over the entire motion arc, associated to a considerable anterior motion in dorsiflexion and posterior motion in plantarflexion of the meniscal-bearing, as predicted by the previous mathematical models. Mean 10.0 and 23.5 degrees respectively of dorsi- and plantar-flexion were measured immediately after implantation, for a mean additional range of motion of 19.2, which was maintained at follow-ups. Radiographs showed good alignment and no signs of evolutive radiolucency or loosening. The mean AOFAS score went from 40.8 pre-op to 66.2, 74.6 and 77.2 respectively at 3, 6 and 12 month follow-ups. One revision only was performed successfully three days after implantation because of a technical error. In the score system utilized, Function and RoM sections scored better than any average previous total ankle result, Pain scored similarly. The satisfactory though preliminary observations from this novel design encourage continuation of the implantation, which is now extended over a few European countries. Instrumented gait and three-dimensional fluoroscopic analyses are in progress to quantify functional progresses

Optical motion analysis (MA) is a useful tool for evaluating musculoskeletal function in health and disease. MA is particularly useful in quantifying joint kinematic and kinetic abnormalities accompanying osteoarthritis. However, current practice does not allow the joints of the foot to be measured since the foot is treated as a single rigid segment. To develop a multi-segment kinematic model of the foot for use in a clinical motion analysis laboratory. Apply the model to a healthy population during normal walking and gait intentionally disrupted by a high arch orthotic. The foot was defined as five rigid segments: hindfoot (calcaneus), midfoot (tarsus), medial forefoot (first metatarsal), lateral forefoot (fifth metatarsal) and the hallux (both phalanges). Each of these segments were tracked individually using custom-built marker triads attached to the skin. Thirty healthy subjects (eleven male, nineteen female; mean age 27.7 years, range 19–53) were examined using MA (eight Eagle camera, EvaRt system, Motion Analysis Corp., Santa Rosa, CA, USA) during normal walking and gait disrupted with a high arch orthotic taped to the plantar surface. All trials were performed barefoot. The special foot marker system was applied to the right foot with the remaining markers in the Helen Hayes configuration. Three motions are reported. The hallux-medial forefoot angulation (HA) is reported in the sagittal plane (plantar-dorsiflexion). The hindfoot-midfoot angulation (HFA) is also reported in the sagittal plane (plantar-dorsiflexion). The height-to-length ratio of the medial-longitudinal arch (MLA) is reported, normalised to zero in quiet standing. Paired t-tests compared the normal and disrupted gait conditions. All angles were compared at the instant of foot flat. HA was not significantly changed between normal and disrupted conditions: from 8.5° ± 6.4° to 8.6° ± 7.4° (p=0.88). The HFA plantar-flexion significantly increased from 0.5 ° ± 3.3° (normal) to 2.9° ± 4.4° (disrupted; p< 0.01); mean difference = +2.5° (95% CI: 0.81 to 4.1°). The MLA was significantly increased (arch raised) from 0.004 ± 0.018 (normal) to 0.017 ± 0.021 (disrupted; p< 0.01); mean increase = +0.012 (95% CI: 0.00421 to 0.021). A multi-segment kinematic model of the foot has been successfully implemented in an optical motion analysis laboratory. The model was sensitive to an intentional disruption of normal foot kinematics during walking in a healthy population

Background: Interventional MRI provides a novel non-invasive method of in-vivo weight-bearing analysis of the subtalar joint. Preceding in-vivo experimentation with stereophotogammetry of volunteers embedded with tantalum beads has produced valuable data on relative talo-calcaneal motion (Lundberg et al. 1989). However the independent motion of each bone remains unanswered. Materials and Methods: Six healthy males (mean 28.8 years), with no previous foot pathology, underwent static right foot weight bearing MRI imaging at 0°, 15° inversion, and 15° eversion. Using identifiable radiological markers the absolute and relative rotational and translational motion of the talus and calcaneum were analysed. Results and Discussion:Inversion: The calcaneum externally rotates, plantar-flexes and angulates into varus. The talus shows greater plantar-flexion with similar varus angulation, with variable axial rotation. Relative talo-calcaneal motion thus involves, 6° relative talar internal rotation, 3.2° flexion and no motion in the frontal plane. Concurrently the talus moves laterally on the calcaneum, by 6.5mm, with variable translations in other planes. This results in posterior facet gapping and riding up of the talus at its posterolateral prominence. Eversion: The calcaneum plantar-flexes, undergoes valgus angulation, and shows variable rotation in the axial plane. The talus plantar-flexes less, externally rotates, and shifts into varus. Relative motion in the axial plane reverses rotations seen during inversion (2.5° talar external rotation). The 8° of relative valgus talo-calcaneal angulation is achieved consistently through considerable varus angulation of the talus, in a direction opposite to the input motion. This phenomenon has not been previously reported. From coronal MRI data, comparative talo-calcaneal motion in inversion is prevented by high bony congruity, whereas during eversion, the taut posterior tibio-talar ligament prevents talar valgus angulation. Conclusion: We have demonstrated that Interventional MRI scanning is a valuable tool to analysing the weight bearing motion of the talo-calcaneal joint, whilst approaching the diagnostic accuracy of stereophoto-gammetry. We have also demonstrated consistent unexpected talar motion in the frontal plane. Talo-calcaneal motion is highly complex involving simultaneous rotation and translation, and hence calculations of instantaneous axes of rotation cannot effectively describe talo-calcaneal motion. We would suggest that relating individual and relative motion of the talus / calcaneum better describes subtalar kinematics