The paper deals with the torques of external muscles acting on the upper ankle joint under weight-bearing conditions and their importance in diagnosing and treating the human foot. Experimental data were collected and calculations were performed. Based on the experiments with the biomechanical model of the foot and upper ankle joint, it was shown how the changes in the force arms of the external muscles of the foot under weight-bearing conditions, change the torque. The real values of muscle forces and torques of the external muscles of the foot were calculated. Taking into account the distance of the lines of muscle action from the axis of rotation of the upper ankle joint the rotational force of the muscles was calculated. The influence of changing the force arm on the rotational efficiency of the muscle balancing the moment of gravity was shown. Knowledge of muscle torque under weight-bearing conditions is crucial for correctly assessing foot biomechanics. It has been shown that torque (gravitational and muscular), not pure force, is crucial when assessing the rotational capacity of the analyzed joint. A change in the approach to diagnostics and treating paresis or weakness of extrinsic foot muscles was proposed through the manipulation of the distance of their action line from the axis of joint rotation.

OBJECTIVE: The aim of this paper is to describe the anterolateral approach using an anatomical plate for ankle arthrodesis and to present the first mid-term results with this technique in a high-risk population.
METHODS: The indication for arthrodesis of the ankle joint with this described technique is moderate to severe osteoarthritis of the ankle.
METHODS: In addition to the general contraindications typical of any operation, there is a specific contraindication in cases of active infection of the soft tissues and accompanying osteomyelitis at the ankle.
METHODS: The incision is made along the course of the peroneus tertius muscle. After that, the mobilization of the peroneus superficialis nerve is carried out, followed by the mobilization of the long extensor tendons, especially the extensor digitorum muscle in a medial direction opening the capsule and removal of the residual cartilage on the distal tibia and talus. Subsequently, the subchondral sclerosis is opened, and the implantation of a suitable osteosynthesis material, e.g., an anatomical angle-stable plate, is carried out. Finally, wound closure is performed involving the muscle belly of the extensor digitorum muscle covering the plate.
METHODS: Immobilization of the ankle for 5-7 days in a dorsal knee-high splint. Retention in a walker after decongestion for another 5 weeks. Increased loading can be done after X‑ray/computed tomography (CT) control from the 6th week.
RESULTS: In all, 11 patients were observed retrospectively for an average of 14 months. There were no complications. The European Foot and Ankle Society (EFAS) score improved significantly from 3.3 to 17.8 points. All patients were subjectively satisfied with the result and would have the operation again.
UNASSIGNED: OPERATIONSZIEL: Ziel der Operation ist die Arthrodese des Sprunggelenkes bei symptomatischer Knorpeldestruktion des oberen Sprunggelenkes.
UNASSIGNED: Die Indikation zur Arthrodese des Sprunggelenkes mit dieser beschriebenen Technik besteht bei mittel- bis hochgradiger Arthrose des oberen Sprunggelenkes (OSG).
UNASSIGNED: Neben den für jede Operation typischen allgemeinen Kontraindikationen besteht spezifisch eine Kontraindikation bei florider Infektion der Weichteile sowie begleitender gelenknaher Osteomyelitis.
UNASSIGNED: Die Schnittführung erfolgt entlang des Verlaufes des M. peroneus tertius. Hiernach wird die Mobilisation des N. peroneus superficialis und Sicherung des Nerven durchgeführt. Im Weiteren erfolgt die Mobilisation des M. extensor digitorum nach medial. Im Anschluss wird die Kapsel eröffnet und der Restknorpel an der distalen Tibia sowie am Talus entfernt. Hiernach wird die subchondralen Sklerose eröffnet. Es erfolgt die Implantation einer anatomischen winkelstabilen Platte. Hiernach wird der Wundverschluss unter Einbeziehung des Muskelbauches des M. extensor digitorum über dem Osteosynthesematerial durchgeführt.
UNASSIGNED: Zur Weiterbehandlung erfolgt zunächst die Ruhigstellung des OSG für 5 bis 7 Tage in dorsaler kniehoher Schiene mit anschließender Retention im Walker nach Abschwellen für weitere 5 Wochen. Die Aufbelastung kann nach Röntgen/Computertomographie (CT)-Kontrolle ab der 6. Woche erfolgen.
UNASSIGNED: Elf Patienten wurden über durchschnittlich 14 Monate retrospektiv beobachtet. Es gab keine Komplikationen. Der European Foot and Ankle Society(EFAS)-Score verbesserte sich signifikant von 3,3 auf 17,8 Punkte. Alle Patienten waren mit dem Ergebnis subjektiv zufrieden und würden sich erneut operieren lassen.

The hook test is a widely used intraoperative method for assessing syndesmosis stability. However, there are no recommendations regarding the force required to perform this test. Furthermore, the reliability of the test is unclear. Ten experienced surgeons performed hook tests on a cadaver bone model. The applied forces were recorded in a blinded manner. In addition, standardized hook tests with defined forces (50, 80, and 100 N) were performed on 10 pairs of cadaver lower legs and the syndesmosis was sequentially destabilized. Diastasis of the syndesmosis was recorded using an optical 3D camera system. A median force of 81 N (Range: 50 N-145 N) was applied. A proportion of 82% of the tests showed a force < 100 N. The data showed good intraraterreliability and poor interraterreliability. In the standardized investigation of the hook test on the cadaver bone model, both the force and the instability of the syndesmosis had a significant influence on the syndesmosis diastasis. Nevertheless, even with maximum instability of the syndesmosis, diastasis > 2 mm could only be measured in 12 of the 19 evaluable specimens. The widely used hook test shows a high variability when performed in practice. Even in a standardized manner, the hook test cannot detect a relevant syndesmosis injury.

In the treatment of ankle fractures, complications such as wound healing problems following open reduction and internal fixation are a major problem. An innovative alternative to this procedure offers a more minimally invasive nail stabilization. The purpose of this biomechanical study was to clarify whether this method was biomechanically comparable to the established method. First, the stability (range of motion, diastasis) and rotational stiffness of the native upper ankle were evaluated in eight pairs of native geriatric specimens. Subsequently, an unstable ankle fracture was created and fixed with a locking plate or a nail in a pairwise manner. The ankles showed significantly less stability and rotational stiffness properties after nail and plate fixations than the corresponding native ankles (p < 0.001 for all parameters). When comparing the two methods, both showed no differences in their range of motion (p = 0.694) and diastasis (p = 0.166). The nail also presented significantly greater rotational stiffness compared to the plate (p = 0.001). However, both fixations remained behind the native stability and rotational stiffness. Due to the comparable biomechanical properties of the nail and plate fixations, an early weight-bearing following nail fixation should be assessed on a case-by-case basis considering the severity of fractures.

The case describes the revision of an upper ankle prosthesis because of loosening. When ankle replacement is the first choice and actual bone quality does not allow a replacement of the prosthesis, arthrodesis is the only way of reducing pain and gaining stability. The amount of missing bone due to the removed prosthesis was severe. Shark Screws®, made of human allograft cortical bone, were used to fix an allograft femoral head and tibia as well as fibula and talus to each other for stabilization. This was performed without any autologous bone graft and without metal screws. The human matrix of the cortical allograft allows the creation of new vessels followed by osteoblastic activity and production of new bone. The revascularization of the allografts reduces the risk of infection and wound problems. Over time, the patient\'s bone metabolism allows the allografts to be remodeled into the patient\'s bone. The case reported here had severe multimorbidity. The loosening of the prosthesis mainly affected the ability to perform housework, mobility, enjoying leisure, and it had a great impact on the emotion and well-being of the patient. One year after surgery, the patient is very satisfied to be able to walk without pain and scratches for about 90 min.

BACKGROUND: This biomechanical study aimed to test if the fixation of the posterior malleolus (PM) only with screws inserted from posterior to anterior (PA) restores stability comparable with the natural condition. The extent of stability was also compared with that of anterior to posterior (AP) screw osteosynthesis (OS) with an additional syndesmotic screw (SS).
METHODS: First, the stability of the upper ankle joint in seven pairs of intact lower legs were examined. Subsequently, half of the lower legs were treated with PA screw fixation of a PM fracture without SS and the other half with AP screw fixation with additional tricortical SS.
RESULTS: PA OS without SS showed significantly more diastasis (p = 0.027). The AP OS with an SS revealed a diastasis that was comparable with the intact condition (p = 0.797). The use of SS led to significantly higher stability compared to OS without SS (p = 0.019).
CONCLUSIONS: The Fixation of the PM alone without an additional syndesmotic screw cannot achieve intact upper ankle stability. Fixation of a PM fracture with an SS helps in nearly achieving the natural condition.

BACKGROUND: Suture-button repair is a widely accepted surgical treatment for acute and isolated ankle syndesmosis injuries. To our knowledge, midterm results have not previously been reported.
OBJECTIVE: To evaluate the clinical, qualitative, and quantitative radiological midterm outcomes of suture-button repair after acute isolated ankle syndesmosis injuries.
METHODS: Retrospective case series; Level of evidence, 4.
METHODS: Clinical outcomes were measured using the Foot and Ankle Disability Index (FADI) and the American Orthopaedic Foot and Ankle Society (AOFAS) score. Three-tesla magnetic resonance imaging (MRI) was performed bilaterally at the ankle. Besides morphological sequences for evaluation of the syndesmosis and degenerative changes of the ankle using the Ankle Osteoarthritis Scoring System (AOSS), the MR protocol included a coronal 2-dimensional multislice multiecho sequence for quantitative cartilage T2-weighted mapping. Spearman correlations and paired t tests were used for statistical analysis.
RESULTS: This retrospective study included 19 consecutive patients (mean age, 29.7 ± 11.5 years) with acute isolated syndesmosis injuries treated with a suture-button system between January 2006 and June 2014, with a mean follow-up of 5.1 ± 2.6 years. Postoperatively, the median FADI score was 136 (range, 78-136), and the median AOFAS score was 100 (range, 87-100). Seventeen (89.5%) patients reported to have reached their preinjury level of sports activities. MRIs of 16 patients were obtained and all showed intact anterior and posterior syndesmotic ligaments; however, in most patients, the previously injured syndesmotic ligament was thickened compared with the uninjured ankle. Average width of the anterior (P = .81) and posterior (P = .60) syndesmosis was not significantly different between the ipsilateral (3.2 ± 1.2 and 4.4 ± 0.9 mm) and contralateral ankles (3.0 ± 0.6 and 4.2 ± 0.7 mm). The median AOSS score was 1.5 (range, 0-11) for the ipsilateral ankle and 0 (range, 0-6) for the contralateral ankle. T2 values of articular cartilage did not significantly differ between the involved and the uninjured ankle (P = .68). Five patients needed hardware removal due to persistent skin irritation, and 1 patient suffered from reinstability of the ankle resulting in revision surgery 2 years after the index surgery.
CONCLUSIONS: Suture-button fixation is an excellent treatment for acute and isolated syndesmosis injuries, resulting in stable ankles without early or advanced osteoarthritic changes at midterm follow-up.