Geert Pagenstert

Subchondral osteosclerosis, characterized by an increase of hypomineralized bone material, is a pathological hallmark of osteoarthritis. The cellular components in the subchondral marrow compartment that participate in this aberrant bone remodeling process remain to be elucidated. This study assessed the presence of marrow inflammatory cells and their relative abundance between nonsclerotic and sclerotic tissues in knee osteoarthritis. Bone samples from osteoarthritic knee tibial plateaus were stratified for histological analyses using computed tomography osteoabsorptiometry. Immunohistological analysis revealed the presence of CD20 (B-lymphocyte) and CD68 (macrophage), but not CD3 (T-lymphocyte) immunoreactive mononuclear cells in subchondral marrow tissues and their relative abundance was significantly increased in sclerotic compared with nonsclerotic bone samples. Multinucleated osteoclasts that stained positive for CD68 and tartrate-resistant acid phosphatase, predominantly asso...

Osteoarthrits is listed number one reason for adult disability. Therefore treatment of arthritis has maximum impact for the general practitioner. Disability of knee and ankle osteoarthritis causes inability to work and loss of independence. Patients will ask their physicians about expectations after total knee or ankle arthroplasty when other treatment has failed. The satisfaction rate after knee prosthesis is 75 – 89 % and for total ankle arthroplasty even slightly higher at 79 – 97 %. This is surprising because the survival in joint registry data after knee arthroplasty is 94 % compared to ankle arthroplasty significantly less at 69 % after 10 years, when a component revision is used as endpoint. In addition, knee component revision usually means exchanging to knee revision prosthesis while at the ankle it is usually prosthetic removal and conversion to ankle fusion. This difference of satisfaction is probably caused by the fact that knee arthroplasty is a standard operation and patients have very high expectations. Key to this is realistic patient education before surgery by general practitioners and specialists about the typical postoperative course with significant pain reduction not within days but rather in the first 2 postoperative years with moderate activity allowed. Candidates for total ankle replacement must be carefully selected because the prosthesis relies on a good bone stock, stable ligaments and proper limb alignment. Unlike for the knee, none of these can currently be corrected by the ankle prosthesis itself. Patients can expect significant pain reduction, better function and a slight improved range of motion after knee and ankle prosthesis. Sports activities are possible, but should be in a low-impact area. Heavy physical work or running and jumping activities are usually not possible and surely not recommended due to increased wear.

Precise knowledge of lateral ankle ligaments anatomy and biomechanics is mandatory for successful surgical reconstruction. The displayed reconstruction procedure fulfilled these requirements, and showed excellent clinical outcome. The described harvesting of the plantaris tendon at the proximal calf allows the use of a relatively long tendon autograft compared with the traditional harvesting procedure at the os calcis. Consequently, this procedure gives the surgeon a more efficient access to a local tendon autograft for numerous surgical procedures in the field of foot and ankle surgery.

The medial ligaments of the ankle are injured more often than generally believed. Complete deltoid ligament tears are occasionally seen in association with lateral malleolar fractures or bimalleolar fractures. Chronic deltoid ligament insufficiency can be seen in several conditions, including posterior tibial tendon disorder, trauma- and sports-related deltoid disruptions, and valgus talar tilting in patients who have a history of triple arthrodesis or total ankle arthroplasty. This article focuses on the anatomy and function of the medial ligaments of the ankle and establishes a rationale for the diagnosis and treatment of incompetent deltoid ligament.

This study reports first evidence of a modified procedure for osteochondral autologous transplantation where bony periosteum-covered plugs are harvested at the iliac crest and transplanted into the talar osteochondral lesion. Thirteen out of 14 patients, average age 39.6 (SD 14.4) years, were followed clinically and radiographically for a median of 25 (24-28) months (minimal follow-up, 24 months). For these 13 patients, the American Orthopaedic Foot and Ankle Society hindfoot score increased from 47 (SD 11) points pre-operatively, to 81 (SD 14) points postoperatively (p < 0.0001). The average pain score decreased from 6.6 (SD 1.3) points pre-operatively, to 1.4 (SD 1.9) points postoperatively (p < 0.0001). Seven patients returned to sports activity. Radiographically good plug osteointegration was observed in nine out of 11 ankles. Follow-up arthroscopy showed fibrous cartilage in four ankles, periosteum hypertrophy in five ankles, and partial or total missing of coverage of the bone in three ankles. Three revision surgeries had to be performed. This modified mosaicplasty might be recommended for severe and recurrent osteochondral lesions of the talus and may lead to restoration of the subchondral bone stock, formation of fibro-cartilage, and stable joint function. IV.

Total ankle replacement is becoming an increasingly used treatment for patients with degenerative arthritis of the ankle; however, there is limited literature available addressing the incidence of thromboembolic complications after total ankle replacement. Therefore, we performed a systematic literature review addressing thrombosis prophylaxis and incidence of thromboembolic complications after total ankle replacement. Furthermore, we evaluated the incidence of thromboembolic complications in our clinic. A systemic literature review was performed using established medical literature data bases. The following information was retrieved from the literature: thrombosis prophylaxis and duration and deep vein thrombosis/pulmonary embolism as postoperative complication. The incidence of thromboembolic complications was evaluated in our patient cohort including 964 total ankle replacement procedures. A total of 21 clinical studies were included in the systematic literature review. The range of incidence of thromboembolic complications was between 0.0 % and 4.8 %. In our patient cohort the incidence of symptomatic deep vein thrombosis was 3.4 %. There were no cases of pulmonary embolism. All patients received low molecular weight heparin prophylaxis. The incidence of thromboembolic complications in our patient cohort was comparable to that of symptomatic deep vein thrombosis in patients undergoing total knee or hip replacement or ankle fusion. We suggest the prophylactic use of low molecular weight heparin for patients after total ankle replacement.

Chronic ankle instability represents a typical sports injury which can mostly be seen in basketball, soccer, orienteering and other high risk sports. 20 to 40 % of the acute ankle sprains develop into chronic ankle instability. From a sports orthopaedic point of view, chronic ankle instability can be subdivided into a lateral, medial or a combination of both so called rotational ankle instability. From a pathophysiological point of view, chronic ankle instability can be either mechanical with a structural ligament lesion or functional with loss of the neuromuscular control. For the sports physician, the chronic ankle instability is a difficult entity as the diagnosis is usually complex and the therapy usually surgical. This review on chronic ankle instability addresses pathomechanism, diagnostics, indications for conservative and surgical treatments, and possible long-term sequelae, as ligamentous osteoarthritis.

ABSTRACT Introduction Magnet resonance imaging (MRI) is the gold-standard of non-invasive diagnostics in OCL of the talus. Single photon emission computed tomography – computed tomography (SPECT-CT) shows additional, high-resolutioned information of osteoblastic (szintigraphic) activity and bony morphology. The study aimed for evaluating the influence of the SPECT-CT on clinical application of the imaging information and decision-making in OCL therapy. Methods MRI and SPECT-CT of 26 patients (average age: 32 y) were analyzed separately by 3 blinded, independent orthopaedic foot and ankle surgeons experienced in treating OCL and working with MRI and SPECT-CT for treatment decision-making. Imaging information was analyzed by using a specified questionnaire. Results By the SPECT-CT, a change in treatment was documented in 46 of 78 decisions (59%) in comparison to the MRI. Following treatment decisions were chosen most often (total decisions: 156): Retrograde drilling: 64 (41.0%); microfracture and antegrade drilling: 28 (17.9%); osteochondral autologous transplantation (mosaicplasty): 23 (14.8%); excision and debridement: 16 (10.3%); physiotherapy: 9 (5.8%); autologous chondrocyte implantation: 5 (3.2%); joint-sacrificing therapy (e.g. joint replacement): 5 (3.2%); cancellous bone grafting: 4 (2.6%); passive conservative therapy (e.g. cast): 1 (0.6%); drug therapy (e.g. hyaluronic acid): 1 (0.6%); refixation: 0 (0%). However, overall distribution of therapies remained unchanged between MRI and SPECT-CT. The questionnaire revealed main differences in imaging interpretation for: subchondral bone plate morphology (17; 65%), subchondral sclerosis (16; 62%), subchondral cysts (11; 42%), and kissing lesions (10; 38%). The area of szintigraphic activity in comparison to bone bruise was found to be smaller in 50% of cases (13) and bigger in 27% (7 cases). Discussion The additional information provided by the SPECT-CT influences the decision-making for the treatment of OCL in the talus significantly. This is due to changed interpretation of subchondral bone plate morphology and subchondral bone activity. No study reported on SPECT-CT in OCL yet. SPECT-CT may become important in diagnostics and treatment decision-making in OCL of the talus.

Introduction: Joint preserving surgeries have gained popularity as treatment of asymmetric early and mid-stage ankle osteoarthritis. However, only limited long-term data on strength and walking biomechanics are available. Therefore, the purpose of this study was to quantify isometric plantar- and dorsiflexion strength and gait parameters (dynamic range of motion, peak moments) in patients who underwent realignment surgery. Methods: Eight patients, a minimum of seven years after realignment surgery (age: 44.7 ± 7.0 years); body mass index (BMI): 27.2 ± 4.6), and eight age-and gender matched healthy controls (age: 44.3 ± 6.6 years; BMI: 25.2 ± 3.4 kg/m2) were included in the study. The measurements consisted of 1) an instrumented gait analysis with a six camera motion analysis system (Vicon, Oxford, UK) and two force plates (Kistler, Winterthur, Switzerland) to assess ankle, knee, and hip kinematics and kinetics, and 2) an isometric torque measurement (torque transducer: SM-500N, Inte...

Introduction: Osteoarthritis (OA) of the ankle is often asymmetric with a hindfoot malalignment into varus or valgus. Patients often have partially intact articular cartilage and can benefit from joint preserving realignment surgery with hindfoot and supramalleolar osteotomies. The purpose of this study was to quantify bilateral biomechanical and neuromuscular adaptations during walking in patients with asymmetric ankle OA before and after realignment surgery. Methods: A 3D gait analysis with bilateral surface electromyography (EMG) of gastrocnemius medialis, soleus, peroneus longus, and tibialis anterior was performed in: 7 patients with asymmetric ankle OA before (P1a) and 12 to 18 months after surgery (P1b), 7 other patients 8 to 9 years after surgery (P2), and 15 healthy subjects (C). For each subject 6 trials were recorded. EMG envelopes of each muscle were analyzed using principal component analysis (input: 101 time points x 432 trials). The first 2 principal components (PC) s...

We analyzed the histopathologic findings in end-stage osteoarthritic ankle joint tissue that display increased uptake of bone-seeking radiotracer in single-photon emission computed tomography-computed tomography (SPECT-CT) imaging. Six consecutive patients with end-stage osteoarthritis undergoing total ankle replacement received preoperative SPECT-CT imaging using (99m)Technetium dicarboxypropane diphosphonate ((99m)Tc-DPD). Using imaging data for stratification, osteochondral tissue sections were prepared from SPECT-positive (+) and -negative (-) areas of tibial and talar resection specimens. Histomorphometric analyses of osteoblast numbers, collagen deposition, and cartilage degeneration were performed on hematoxylin and eosin, van Gieson's and Safranin-O stained tissue sections. Osteoclast activity was visualized using tartrate-resistant acid phosphatase (TRAP) staining. Increased (99m)Tc-DPD uptake was observed exclusively subjacent to the subchondral bone plate of tibial an...

Objective: Single photon emission computed tomography (SPECT)-CT is an emerging diagnostic imaging tool for osteoarthritis (OA). While subchondral bone sclerosis is a hallmark of end-stage OA, the cellular and molecular mechanisms of increased bone turnover in OA remain elusive. In this study, we investigated the cellular mechanisms of increased bone remodeling, defined by SPECT-CT, in patients suffering from end-stage ankle OA. Methods: Pre-operative SPECT-CT imaging, using 99mTechnetiumdicarboxypropane diphosphanate (99mTc-DPD), was performed in six consecutive OA patients (mean age 63, range 52–72) undergoing total ankle replacement. AOFAS score and VAS were used for clinical evaluation in this study group. Intra-operative distal tibial and talar resections were obtained and standardized samples (5 x 5 mm) were divided into four categories according to subchondral bone density (low or high) and 99mTc-DPD uptake (negative or positive). For histological analyses, tissue sections (1...

Introduction: Single photon emission computed tomography (SPECT)/CT enables accurate non-invasive and simultaneous acquisition of information on tissue morphology and biological processes in disease. SPECT/CT imaging using a radiographic bone tracer, such as 99mTechnetium-dicarboxypropane diphosphanate (99mTc-DPD), is frequently applied for differential diagnosis of foot and ankle pathologies that pose a diagnostic challenge due to their complex anatomy. Uptake of bone-seeking radiotracers is primarily determined by the degree of bone perfusion and chemisorption to the hydroxyapatite structure of bone tissue and can be influenced by environmental factors, such as pH. In this study we sought to identify the cellular and morphological changes that associate with increased 99mTc-DPD uptake in ankle joint osteoarthritis (OA). Methods: Six consecutive patients with end-stage ankle OA scheduled for total ankle replacement received preoperative 99mTechnetium-dicarboxypropane-diphosphanate ...

ABSTRACT Osteochondral lesions of the talus often affect young, sports active patients. Different pathomechanisms influence the development of an osteochondral lesion: trauma, ligamentous instability, hypovascularity, and malalignment. To the understanding of the authors, pathomechanisms have to be diagnosed and considered for the choice of treatment. The choice of treatment is wide. Only few qualitative studies offer answers to guide the therapy. A big part of therapy relies on the experience and know-how of the surgeon. Chondral, osseous and osteochondral therapies are available. This review offers an over-view of the actual know-how and treatment options.

About 1% of adults suffer from painful osteoarthritis of the ankle. The current literature contains no information on the percentage of such patients who derive long-term relief of symptoms from conservative treatment. Advanced ankle osteoarthritis can be treated with non-joint-preserving measures, such as total ankle replacement and ankle fusion. This review is based on selected relevant publications, guidelines from Germany and abroad, and the authors' personal experience. Before surgery is considered, conservative measures such as physiotherapy and orthopedic aids should be used to the fullest possible extent. No randomized trials have yet been published comparing total ankle replacement with ankle fusion. Total ankle replacement with newer types of prosthesis yields good to very good intermediate-term and long-term results, with mean success rates of up to 90% at 10 years (range, 68-100%). Independent risk factors for the failure of ankle replacement are age over 70 years (o...

More than half of the patients with ankle osteoarthritis have a malalignment of the hindfoot. These patients might benefit from joint-preserving realignment surgery. This article provides an overview of the effects of asymmetric ankle osteoarthritis on the patients' biomechanical and neuromuscular gait patterns in comparison to data from healthy subjects. Furthermore, data from gait analyses after joint-preserving realignment surgery are presented that give an indication of the biomechanical and neuromuscular adaptations to supramalleolar osteotomies.

Pain is the key symptom of patients suffering from osteochondral lesions (OCLs) of the ankle joint. Routine radiographic imaging methods for diagnosis and staging of OCL fail to visualize the pain-inducing focus within the joint. SPECT-CT (Single-photon emission computed tomography-computed tomography) is a new hybrid imaging technique allowing exact digital fusion of scintigraphic and computer tomographic images. This allows precise localization and size determination of an OCL within the joint. Using this novel imaging method, we conducted a study to evaluate the correlation between pathological uptake within an OCL and pain experienced by patients suffering from this condition; 15 patients were assessed in the orthopaedic ambulatory clinic for unilateral OCL of the ankle joint. Pain status was measured with the Visual Analogue Scale (VAS). A SPECT-CT was performed. All patients underwent CT-guided ankle injection with a local anesthetic and iodine contrast medium. The VAS score a...

The upper ankle joint is one of the target-joints of the haemophilic patient. Therefore, the secondary arthritis of the upper ankle joint is one of the most frequent forms of haemophilic arthropathy. It is a secondary form of arthritis not only because of chronic synovitis and cartilage injury resulting from chronic recurrent intraarticular bleeds, but also due to the misalignment of the joint and abnormal joint stress. The consequences are manifest even in young patients and finally lead to upper ankle joint arthritis. In such clinical situations, the upper ankle joint-arthroplasty is a viable alternative to arthrodesis. After several years of bleeding of the upper ankle joint many patients with haemophilia suffer from symptomatic arthritis. Open joint cleansing considerably improves mobility in the upper ankle joint and alleviates the pain in the talonavicular joint. However, the recovered mobility of the arthritic upper ankle joint also activates arthritis, associated with severe...

Pseudo tumours are amongst the rare yet pathognomonic complications of haemophilia. They are old, encapsulated haematomas which due to their sometimes enormous size can cause massive complaints. These haematomas are surrounded by a thick fibrous capsule. They are attributed to persistent bleedings. The pathophysiology of pseudo tumors is not conclusively established yet. Some believe that they originate from bone material or the periosteum, while others suggest their development from soft tissue. They spread aggressively, displace the surrounding tissue, and cause secondary periosteal erosion of the bone. This results in bone resorption and destruction of surrounding muscular and soft tissue. Pseudo tumours develop slowly over many years. They occur primarily in adults and are largely unresponsive to conservative treatment. A 48-year-old man with moderate hemophiliaA (FVIII:C 2%) and no FVIII inhibitor. Due to recurrent bleeding into the muscle of the right thigh diagnosis of two ps...

Secondary arthrosis of the upper ankle joint (talocalcanean joint) is one of the most frequent forms of haemophilic arthropathy. It is a secondary form of arthrosis not only because of chronic synovitis and cartilage injury resulting from chronic recurrent intraarticular bleeds, but also due to the misalignment of the joint and abnormal joint stress. The consequences are manifest even in young patients and finally lead to subtalar joint ankylosis with the biomechanical disorder of foot drop (talipes equinus). In such clinical situations, implantation of a subtalar joint endoprosthesis is a viable alternative to arthrodesis. A man (age: 52 years), suffering from severe haemophilia A (residual FVIII activity < 1 %), no inhibitor formation. The patient has a history of several years of painful ankylosis of the right ankle joint and minor talipes equinus, and suffers from symptomatic talonavicular arthrosis. Open joint cleansing considerably improved mobility in the upper ankle joint...

The purpose was to measure the effect of flexion and additional rotation of the femur relative to the tibia on the tuberosity-trochlear groove distance (TT-TG) in the same subject in 20 cadaveric knees joint. In 20 human adult cadavers, formal fixed knees (age: 81.9 years, SD 12.3; 10 female) CT scans were performed in extension and 30° of flexion as well as in neutral, maximal possible internal (IR), and external rotation (ER). On superimposed CT scan images, TT-TG was measured in each position. TT-TG measurements were correlated in all knee positions. TT-TG in full extension/neutral rotation was 7.8 mm (SD 3.4, range, 2.4-15.3). TT-TG in full extension and IR was significantly lower, and TT-TG in full extension and ER was significantly higher than in neutral rotation (5.4 ± 2.3 vs. 10.9 ± 4.8 mm; P < 0.001). IR and ER varied between 1.0°-7.6° and 0.2°-9.2°, respectively. TT-TG in 30° flexion/neutral rotation was 3.9 mm (SD 1.8, range, 1.3-7.8), which was significantly lower than in full extension and neutral rotation (P < 0.001). TT-TG in 30° flexion and IR was significantly lower, and TT-TG in 30° flexion and ER was significantly higher than values obtained in neutral rotation (2.7 ± 1.2 vs. 6.5 ± 3.4 mm; P < 0.001). IR and ER in 30° flexion varied between 0.6°-10.7° and 1.9°-13.0°, respectively. Flexion as well as rotation of the knee joint significantly alters the TT-TG. These results may have wider clinical relevance in assessing TT-TG and further decisions based on it.

ABSTRACT Einleitung Auch bei strenger Indikation hat das laterale Release (LR) der Patella in bis zu 30% Komplikationen wie Rezidiv der Hyperkompression oder mediale Patella-Instabilität. Daher wurde statt der Durchtrennung eine z-Verlängerung des lateralen Retinakulum-Kapsel-Komplexes (LV) propagiert. Hypothese LV reduziert die Komplikationen des LR bei gleicher Schmerzreduktion. Methode 08/2006–09/2008 wurden 28 Patienten (21 w, 7 m, Durchschnittsalter 42,5 Jahre) mit HKS der Patella, abwechselnd entweder mittels LR (14 Patienten) oder LV (14 Patienten) über eine einheitliche laterale parapatelläre Hautinzision operiert. Operateur, Wundverschluss und Rehabilitationsschema waren gleich. Präoperativ, nach 3, 6, 12 und 24 Monaten erfolgte eine Dokumentation mittels Fragebogen zu Schmerz und Funktion (Kujala Score: 0–100 Punkte), mit Hilfe einer Visual Analog Scala zu Schmerzen (VAS, 0–10 Punkte), Untersuchung zur Hyperkompression (passiver Patella Tilt: positiv-negativ (PPT) und mediale Patella Verschieblichkeit: 0–4 Quadranten (MLV) nach Kolowich), Stabilität (Gravitation-Subluxations-Test nach Nonweiler: positiv-negativ (GST)) und Quadrizepsatrophie (Oberschenkelumfang in cm, 10 cm oberhalb der Patella). Dies erfolgte durch zwei Personen, ohne Wissen über das operative Vorgehen. Ergebnisse Die mittlere Nachkontrollzeit betrug beim LR 21,4 Monate (m) und bei LV 21,7 m (Range jeweils 18–24 m). Von präoperativ zur letzten Kontrolle änderten sich die Variablen wie folgt: Kujala Score verbesserte sich signifikant für LR (p<0,05) von 52,2 auf 77,2 und für LV (p<0,05) von 51,8 auf 88,4 Punkte, mit signifikantem Unterschied zischen den Gruppen (p<0,05). PPT für LR entwickelte sich von positiv in 14 Fällen zu positiv in zwei Fällen und für LV von positiv in 14 zu einem Fall, ohne signifikantem Unterschied zwischen den Verfahren (p>0,05). Bei der MLV für LR änderte sich der Mittelwert von 0,4 Quadranten (Q) zu 2,5 Q (Range, 1–4Q), für LV von 0,4 zu 1,6 Q (Range, 0,5–2 Q), mit signifikantem Unterschied (p<0,05). GST für LR entwickelte sich von positiv in 0 zu 4 Fällen, und blieb für LV unverändert bei 0 Fällen (p<0,05). Die Quadrizepzatrophie im Vergleich zur Gegenseite änderte sich für LR von 0,4 zu 1,8 cm und für LV von 0,4 zu 0,2 cm, mit signifikantem Unterschied zwischen den Gruppen (p<0,05). Diskussion LR und LV eignen sich zur Therapie des HKS der Patella. Allerdings zeigt die LV eine kontrolliertere mediale Patella Verschieblichkeit (niedrigere Range der Werte bei MLV) ohne mediale Instabilität und ohne deren Risikofaktor einer Quadrizepsatrophie, was durch das Erhalten der Kontinuität des Retinakulum-Kapsel-Komplexes erklärt wird. Die Auswirkungen dieser Unterschiede zeigen sich auch in den besseren subjektiven Bewertungen (Kujala Score). Bis zum GOTS-Jahreskongress wird die prospektive Studie abgeschlossen sein (alle Patienten werden bis Juni 2010 mindestens 24 Monate nachkontrolliert sein) und damit ein gültigeres Studienergebnis zu berichten sein.

ABSTRACT Synovialbiopsien werden üblicherweise im Rahmen einer Arthroskopie durchgeführt. Die Indikationen hierfür sind vielfältig und beinhalten die Abklärung von metabolischen, entzündlichen und infektiösen Ursachen der Arthritis, die teilweise auch Sportverletzungen oder Überlastungsreaktionen imitieren können. Wir haben kürzlich ein neues Instrument zur retrograden Synovialbiopsie mitentwickelt (Retroforce, KARL STORZ GmbH, Tuttlingen, Germany). In dieser Studie wurde die Anwendung dieses Instrumentes während der uniportalen Arthroskopie mit der alleinigen Anwendung unter Lokalanästhesie verglichen. Insgesamt wurden zwölf Patienten eingeschlossen, bei denen die Indikation zur Synovialbiopsie gestellt wurde. Bei sechst Patienten wurde die Arthroskopie durchgeführt, bei den anderen sechs Patienten nur die blinde retrograde Synovialbiopsie. Bei allen Patienten konnte genug representatives Material für eine histologische und gegebenenfalls mikrobiologische Diagnose gewonnen werden. Der Zugang erfolgte entweder über den Softspot oder lateralen suprapatellären Rezessus. Komplikationen wie Blutung oder Infektionen sind nicht aufgetreten. Zusammenfassend erscheint die retrograde Synovialbiopsie sowohl im Rahmen einer uniportalen Arthroskopie als auch unter Lokalanästhesie verlässlich und sicher durchführbar.

ABSTRACT Bandläsionen des oberen Sprunggelenkes sind die häufigste Verletzung im Sport. Das Risiko einer Distorsion des oberen Sprunggelenkes (OSG) zu erleiden, hängt von intrinsischen (Rückfußstellung, Laxität, Kraft, neuromuskuläre Reaktion u.a.) sowie extrinsischen Faktoren (Schuhwerk, Sportart, Aufwärmen u.a.) ab. Entsprechende Maßnahmen zur primären Prävention sind das Aufwärmen vor dem Sport, Training der Muskulatur und neuromuskulären Reaktion sowie korrektes Schuhwerk und ggf. äußere stabilisierende Maßnahmen. Die korrekte Behandlung des Erstereignisses einer OSG-Distorsion konservativ und operativ sowie die Behandlung der Risikofaktoren und klinische Nachkontrollen stellen die wichtigsten Bausteine zur sekundären Prävention der chronischen Instabilität dar. Die Behandlung der chronischen Instabilität stellt einen wichtigen Punkt in der tertiären Prävention einer posttraumatisch-ligamentären OSG-Arthrose dar.