O acometimento da articulação radioulnar distal, ocasiona um importante comprometimento funcional da mão, sendo um ponto crítico para a manutenção da estabilidade do antebraço, causando um grande impacto na qualidade de vida desta população. O objetivo foi estudar os pacientes operados pela técnica de Sauvé- Kapandji por diversas etiologias, comparando nossos resultados com os da literatura. O estudo foi de coorte transversal, realizado através de levantamento de 24 pacientes já operados, no período de seis anos, pela técnica de Sauvé-Kapandji em acompanhamento no ambulatório. Os dados pós-cirúrgicos foram de imagem (radiografia), física (Grip e Pinch) e funcional, através de questionário PRWE (Patient Rated Wrist Evaluation) e a auto avaliação do paciente sobre a presença de dor e o resultado funcional da cirurgia. Nossos resultados foram satisfatórios em 62,25% dos casos. A principal indicação foi sequela de fratura de radio distal (62,5%). Houve necessidade de nova intervenção em 37,75%, (9 casos),sendo 7 casos por sintomas de dor na região do parafuso. Nao se observou diferença significativa quando comparado radiografia sem carga e com carga. Houve melhora da dor de 9,2 para 3,46 na nota dada pelo paciente. Quando avaliada a força entre o membro operado e o membro contralateral não foi observada significância estatística, assim como no PRWE. Concluiu-se que os resultados foram satisfatórios indicando bom prognóstico para os pacientes com alteração na articulação radioulnar distal operados pela técnica de Sauvé-Kapandji. Novos estudos clínicos serão necessários para avaliar se esta técnica poderá servir como referência para este tipo de indicação. / The involvement of the distal radioulnar joint causes an important functional impairment of the hand, being a critical point for maintaining the stability of the forearm, causing a great impact on the quality of life of this population. The objective was to study the patients operated by the Sauvé-Kapandji technique for several etiologies, comparing our results with those of the literature. The study was a crosssectional cohort study, carried out by a survey of 24 patients already operated on during the six-year period, using the Sauvé-Kapandji technique under follow-up at the outpatient clinic. The postoperative data were imaging (radiography), physical (Grip and Pinch) and functional, through a PRWE (Patient Rated Wrist Evaluation) questionnaire and the patient\'s self-assessment of the presence of pain and the functional outcome of the surgery. Our results were satisfactory in 62.25% of the cases. The main indication was distal radius fracture (62%).There was need a new intervention in 37.75% (9 cases), with 7 cases due to pain symptoms in the screw region. No significant difference was observed when compared to unloaded and loaded radiography. There was improvement in pain from 9.2 to 3.46 on the patient\'s note. When the strength was evaluated between the operated limb and the contralateral limb, no statistical significance was observed, as in PRWE. It was concluded that the results were satisfactory indicating a good prognosis for patients with alterations in the radioulnar joint operated by the Sauvé-Kapandji technique. Further clinical studies will be needed to assess whether this technique may serve as a reference for this type of indication.

Introduction: The forearm is a complex biological unit, which has allowed man's evolution. This PhD commenced with an analysis of the normal biomechanical functioning of the key components of the forearm: notably the distal radioulnar joint (DRUJ), interosseous ligament (IOL) and proximal radioulnar joint (PRUJ). Understanding normal forearm physiology, a clinical study followed to delineate the pathophysiology of a new clinical entity, related to DRUJ dysfunction. Methods: Biomechanical Study: A biomechanical testing jig was developed to facilitate collection of data about normal functioning of the DRUJ, IOL and PRUJ in both unloaded and loaded states. This permitted testing throughout the range of forearm pronosupination. Thawed fresh frozen cadaveric upperlimbs were mounted into the jig. Using Microstrain® strain gauges and Tekscan™ pressure sensors, the functional anatomy of the key components of the forearm was delineated, both with the forearm flexed at 90° and maximally extended at the elbow. Clinical Study: A series of 3-Tesla MRI scans was undertaken on patients symptomatic of an intermittent ulnar neuropathy. The causative pathophysiology was determined using 3D qualitative and quantitative analyses. Results: Biomechanical Study: Reproducible patterns of force transmitted and joint contact area have been determined for the DRUJ, and for the first time, the PRUJ. With the exception of PMax and P60 for the PRUJ, application of load increases contact areas and transmitted forces across the joints (P<0.05). The converse is true for PMax and P60 in the PRUJ. The IOL is lax during pronation, strain gradually increasing as the arm moves to neutral. In neutral the middle-portion of the IOL (m-IOL) demonstrates most strain, this decreasing again in supination, whilst the distal and proximal portions (d- & p-IOL) exhibit more strain (P<0.05). Axial loading consistently increases strain in all ligaments (P<0.05). Observed behaviour patterns across the joints and in the ligaments alter with elbow extension (P<0.05). Clinical Study: Salient symptoms of the new syndrome were described. Displacement of the ulnar nerve from its normal course was seen with compression/distraction in the distal forearm and Guyon’s canal. This was considered causative of the syndrome. As a by-product of the research, a new clinical device was also developed, which improves the patient pathway when investigating DRUJ dysfunction. Conclusions and Outcomes: This research has analysed normal forearm biomechanics determining that the PRUJ is a load-bearing joint, interrelated with the DRUJ and IOL. Elbow extension has been shown to alter the normal biomechanics of the forearm. A clinical entity of a dysfunctional forearm has been defined, called subluxation-related ulnar neuropathy or SUN syndrome. Finally, a new clinical device has been developed, which it is anticipated will translate into visible improvements in patient care.

Residual dysfunction after a fracture of the distal radius is most often mild but may give rise to significant impairment especially in the younger active population. The symptoms often manifest around the distal ulna when loading the hand or rotating the forearm. In this region are found articular and soft tissue connections running from the distal ulna to the distal radius as well as to the ulnar side of the carpus. The aims of this thesis were to investigate the effects of distal radius fractures on the structures about the distal ulna and to what extent malunion and ulnar soft tissue lesions affect function. Both patients and cadaver specimens were used in the five different studies. In a retrospective study of 17 malunited distal radius fractures supination impairment improved significantly by correction of the skeletal malunion. This highlights the importance of distal radioulnar joint congruity for forearm rotation in a subset of cases. The pathomechanisms of injury to the triangular fibrocartilage complex (TFCC) were studied. In a cadaveric distal radius fracture model different restraining properties and injury patterns were investigated. Similar patterns of injury were then observed in 20 patients with a displaced distal radius fracture. It was found that a TFCC injury can be expected with dorsal displacement of the distal radius fragment of 32o or more from the anatomically correct position. The distribution of a TFCC injury apparently differs depending on the size of an associated ulnar styloid fracture. In cases of an intact ulnar styloid or a concomitant tip fracture (Type 1) the first stage of injury seems to be extensor carpi ulnaris subsheath separation from the distal ulna and the dorsal radioulnar ligament. Thereafter follows a disruption of the deep insertions into the fovea of the ulna starting from the palmar and extending dorsally and radially. An extensive injury can be detected with a novel non-invasive test called the ‘bald ulnar head test’, which is performed under anaesthesia. Diagnosis of an acute TFCC injury is difficult using non-invasive methods. In a prospective study of 48 patients, CT scanning to detect pathologic subluxation was found to be of little use in both acute and chronic cases, and is therefore not endorsed on this indication. A radioulnar stress test, which in previous studies has correlated well to a deep TFCC injury, was found to be highly reliable but not to correspond with significant disability in self-administered questionnaires of functional outcome two years or more after injury. This indicates that the subset of patients possibly benefiting from acute repair must be identified by other means.

Einleitung Die klinische Bedeutung einer radio-ulnaren Inkongrunz (RUI) bei Hunden mit Ellbogengelenksdysplasie, sowie die präzise Bestimmung einer geringgradigen RUI sind umstrittene Fragestellungen in der Kleintierorthopädie. Zielstellung (1) die 3D-Technik zur Bestimmung einer RUI in ihrer Genauigkeit zu verbessern (2) mit Hilfe dieser verbesserten Technik, die Beziehung zwischen Ausprägung und Grad einer vorliegenden RUI und dem Ausmaß an damit verbundenen Gelenkschäden im medialen Kompartiment des Ellbogengelenkes zu untersuchen. Material und Methoden In einer ersten Studie wurden 63 CT-basierte 3D-Modelle der radio-ulnaren Gelenkpfanne mit bekannter RUI (-2mm, -1 mm, 0 mm, +1 mm, +2 mm), unter Verwendung einer Kugel, welche genau der Incisura trochlearis jedes individuellen Modells angepasst war, bezüglich der vorhanden RUI untersucht. Diese Messungen erfolgten geblindet in zufälliger Reihenfolge der 63 Modelle und wurden hinsichtlich Spezifität und Sensitivität ausgewertet. In der zweiten Studie wurden 86 Ellbogengelenke klinischer Patienten retrospektiv mit der neuen 3D-Kugel-Methode bezüglich ihrer RUI vermessen. Dieser Wert wurde in Beziehung mit dem in der Arthroskopie diagnostizierten Gelenkschaden im medialen Kompartiment gesetzt (Korrelation nach Pearson und logistische Regression), wobei die Gelenke in zwei Gruppen unterteilt wurden; die mit geringen Veränderungen (FPC-Gruppe) und solche mit fortgeschrittenen Schäden (MCD-Gruppe). Ergebnisse Unter Verwendung der Kugel-Methode betrug die mediane Sensitivität eine RUI auf einen Millimeter genau zu bestimmen 0,94 wobei die mediane Spezifität bei 0,89 lag. Der intra-Class-Korrelationskoeffizient für die interobserver Übereinstimmung betrug 0,99. 14 % der Gelenke wiesen eine negative RUI auf, 40 % zeigten keine messbare RUI und 46 % wiesen eine positive RUI auf. Das Quotenverhältnis (odds ratio) für das Vorliegen fortgeschrittener Gelenkschäden betrug für jeden Millimeter RUI 6,4. Schlussfolgerungen Die Anwendung der Kugel-Methode verbessert die Diagnose der RUI deutlich. Der vermutete Zusammenhang zwischen RUI und Gelenkschäden konnte mit der klinischen Studie bestätigt werden. Allerdings ist bemerkenswert, dass 40 % der Gelenke keine RUI aufwiesen. Somit ist davon auszugehen, dass andere Faktoren neben einer RUI an der Pathogenese klinisch beobachteter Gelenkschäden beteiligt sind. Ebenso ist festzustellen, dass ca. 15 % der Gelenke eine negative RUI aufweisen. Somit scheint es nicht gerechtfertigt alle Gelenke mit einer Form der Ellbogenosteotomie zu behandeln, da eine negative bzw. positive RUI und insbesondere keine RUI unterschiedliche geometrische Korrekturen benötigen. / Introduction The clinical significance of RUI in dogs with elbow dysplasia and precise estimation of small degree of RUI are controversial topics in small animal orthopedics. Objectives (1) improve the accuracy of the 3D technique for the estimation of RUI (2) using the improved technique to examine the relationship between the shape and degree of present RUI and the amount of related joint damage in the medial compartment of the elbow joint. Material and methods In a first study, 63 CT-based 3D models of the radio-ulnar joint cup with known RUI (-2 mm, -1 mm, 0 mm, mm +1, +2 mm) were examined us-ing a sphere, which was exactly fitted to the trochlear ulnar notch of each individual model. The assessment of the radioulnar joint conformation was evaluated blindly in a random manner and analized in respect to sensitivity and specificity. In the second study, 86 elbow joints of clinical patients were retrospectively graded with the new 3D sphere technique with respect to their RUI. This value was correlated with the arthroscopically diagnosed joint damage in the medial compartment, where the joints were divided into two groups. Those with minor changes (g-FPC) and those with advanced damage (g-MCD). Results By using the sphere fitting technique, the median sensitivity of a RUI on a millimeter basis was 0.94 and the median specificity was 0.89. The intra-class correlation coefficient for interobserver agreement was 0.99. In the clinical joints 14 % had a negative RUI, 40 % showed no measurable RUI and 46% had a positive RUI. The odds ratio for the presence of advanced joint damage for every millimeter RUI was 6.4 Conclusions The application of the sphere fitting technique significantly improves the diagnosis of the RUI. The assumed relationship between RUI and joint damage could be confirmed in the clinical study. However, it is noteworthy that 40 % of the joints showed no RUI. Thus, it can be assumed that other factors besides RUI are playing rule in the pathogenesis of clinically observed joint damages. Also it should be noted that approximately 15 % of the joints have a negative RUI. Thus, it does not seem to be wise to treat all the joints with a type of elbow osteotomy, as a negative or positive RUI and in particular no RUI need different geometric corrections

Optimal management of fractures, post-traumatic arthritis and instability of the distal radioulnar joint (DRUJ) requires an understanding of the forces existing across this joint as a function of the activities of daily living. However, such knowledge is currently incomplete. The goal of this research was to quantify the loads that occur at the DRUJ during forearm rotation and to determine the effect that individual muscles have on those loads. Human and cadaver studies were used to analyze the shear (A-P), transverse (M-L) and resultant forces at the DRUJ and to determine the role that 15 individual muscles had on those forces. Data for scaling the muscles forces came from EMG analysis measuring muscle activity at nine positions of forearm rotation in volunteers during isometric pronation and supination. Muscle orientations were determined from the marked muscle origin and insertion locations of nine cadaveric arms at various stages of forearm rotation. The roles that individual muscles played in DRUJ loading were analyzed by removing the muscle of interest from the analysis and comparing the results. The EMG portion of this study found that the pronator quadratus, pronator teres, brachioradialis, flexor carpi radialis and palmaris longus contribute significantly to forearm pronation. The supinator, biceps brachii, and abductor pollicis longus were found to contribute significantly to supination. The results of the DRUJ analysis affirm that large transverse forces pass from the radius to the ulnar head at all positions of forearm rotation during pronation and supination (57.5N-181.4N). Shear forces exist at the DRUJ that act to pull the radius away from the ulna in the AP direction and are large enough to merit consideration when examining potential treatment options (7.9N-99.5N). Individual muscle analysis found that the extensor carpi radialis brevis, extensor pollicis longus, extensor carpi ulnaris, extensor indicis and palmaris longus had minimal effect on DRUJ loading. Other than the primary forearm rotators (pronator quadratus, pronator teres, supinator, biceps brachii), the muscles that exhibited the largest influence on DRUJ loading were the abductor pollicis longus, brachialis, brachioradialis, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris.

Einleitung Die klinische Bedeutung einer radio-ulnaren Inkongrunz (RUI) bei Hunden mit Ellbogengelenksdysplasie, sowie die präzise Bestimmung einer geringgradigen RUI sind umstrittene Fragestellungen in der Kleintierorthopädie. Zielstellung (1) die 3D-Technik zur Bestimmung einer RUI in ihrer Genauigkeit zu verbessern (2) mit Hilfe dieser verbesserten Technik, die Beziehung zwischen Ausprägung und Grad einer vorliegenden RUI und dem Ausmaß an damit verbundenen Gelenkschäden im medialen Kompartiment des Ellbogengelenkes zu untersuchen. Material und Methoden In einer ersten Studie wurden 63 CT-basierte 3D-Modelle der radio-ulnaren Gelenkpfanne mit bekannter RUI (-2mm, -1 mm, 0 mm, +1 mm, +2 mm), unter Verwendung einer Kugel, welche genau der Incisura trochlearis jedes individuellen Modells angepasst war, bezüglich der vorhanden RUI untersucht. Diese Messungen erfolgten geblindet in zufälliger Reihenfolge der 63 Modelle und wurden hinsichtlich Spezifität und Sensitivität ausgewertet. In der zweiten Studie wurden 86 Ellbogengelenke klinischer Patienten retrospektiv mit der neuen 3D-Kugel-Methode bezüglich ihrer RUI vermessen. Dieser Wert wurde in Beziehung mit dem in der Arthroskopie diagnostizierten Gelenkschaden im medialen Kompartiment gesetzt (Korrelation nach Pearson und logistische Regression), wobei die Gelenke in zwei Gruppen unterteilt wurden; die mit geringen Veränderungen (FPC-Gruppe) und solche mit fortgeschrittenen Schäden (MCD-Gruppe). Ergebnisse Unter Verwendung der Kugel-Methode betrug die mediane Sensitivität eine RUI auf einen Millimeter genau zu bestimmen 0,94 wobei die mediane Spezifität bei 0,89 lag. Der intra-Class-Korrelationskoeffizient für die interobserver Übereinstimmung betrug 0,99. 14 % der Gelenke wiesen eine negative RUI auf, 40 % zeigten keine messbare RUI und 46 % wiesen eine positive RUI auf. Das Quotenverhältnis (odds ratio) für das Vorliegen fortgeschrittener Gelenkschäden betrug für jeden Millimeter RUI 6,4. Schlussfolgerungen Die Anwendung der Kugel-Methode verbessert die Diagnose der RUI deutlich. Der vermutete Zusammenhang zwischen RUI und Gelenkschäden konnte mit der klinischen Studie bestätigt werden. Allerdings ist bemerkenswert, dass 40 % der Gelenke keine RUI aufwiesen. Somit ist davon auszugehen, dass andere Faktoren neben einer RUI an der Pathogenese klinisch beobachteter Gelenkschäden beteiligt sind. Ebenso ist festzustellen, dass ca. 15 % der Gelenke eine negative RUI aufweisen. Somit scheint es nicht gerechtfertigt alle Gelenke mit einer Form der Ellbogenosteotomie zu behandeln, da eine negative bzw. positive RUI und insbesondere keine RUI unterschiedliche geometrische Korrekturen benötigen.:1 EINLEITUNG 1 2 PUBLIKATIONEN 3 2.1 Sensitivity and specificity of 3D models of the radioulnar joint cup in combination with a sphere fitted to the ulnar trochlear notch for estimation of radioulnar incongruence in vitro 3 2.2 Relationship between axial radio-ulnar incongruence with cartilage damage in dogs with medial coronoid disease 16 3 DISKUSSION 32 4 ZUSAMMENFASSUNG 36 5 SUMMARY 38 6 LITERATURVERZEICHNIS 40 / Introduction The clinical significance of RUI in dogs with elbow dysplasia and precise estimation of small degree of RUI are controversial topics in small animal orthopedics. Objectives (1) improve the accuracy of the 3D technique for the estimation of RUI (2) using the improved technique to examine the relationship between the shape and degree of present RUI and the amount of related joint damage in the medial compartment of the elbow joint. Material and methods In a first study, 63 CT-based 3D models of the radio-ulnar joint cup with known RUI (-2 mm, -1 mm, 0 mm, mm +1, +2 mm) were examined us-ing a sphere, which was exactly fitted to the trochlear ulnar notch of each individual model. The assessment of the radioulnar joint conformation was evaluated blindly in a random manner and analized in respect to sensitivity and specificity. In the second study, 86 elbow joints of clinical patients were retrospectively graded with the new 3D sphere technique with respect to their RUI. This value was correlated with the arthroscopically diagnosed joint damage in the medial compartment, where the joints were divided into two groups. Those with minor changes (g-FPC) and those with advanced damage (g-MCD). Results By using the sphere fitting technique, the median sensitivity of a RUI on a millimeter basis was 0.94 and the median specificity was 0.89. The intra-class correlation coefficient for interobserver agreement was 0.99. In the clinical joints 14 % had a negative RUI, 40 % showed no measurable RUI and 46% had a positive RUI. The odds ratio for the presence of advanced joint damage for every millimeter RUI was 6.4 Conclusions The application of the sphere fitting technique significantly improves the diagnosis of the RUI. The assumed relationship between RUI and joint damage could be confirmed in the clinical study. However, it is noteworthy that 40 % of the joints showed no RUI. Thus, it can be assumed that other factors besides RUI are playing rule in the pathogenesis of clinically observed joint damages. Also it should be noted that approximately 15 % of the joints have a negative RUI. Thus, it does not seem to be wise to treat all the joints with a type of elbow osteotomy, as a negative or positive RUI and in particular no RUI need different geometric corrections:1 EINLEITUNG 1 2 PUBLIKATIONEN 3 2.1 Sensitivity and specificity of 3D models of the radioulnar joint cup in combination with a sphere fitted to the ulnar trochlear notch for estimation of radioulnar incongruence in vitro 3 2.2 Relationship between axial radio-ulnar incongruence with cartilage damage in dogs with medial coronoid disease 16 3 DISKUSSION 32 4 ZUSAMMENFASSUNG 36 5 SUMMARY 38 6 LITERATURVERZEICHNIS 40