Christian Ries

Reliability of Magnetic Resonance Imaging Signs of Posterolateral Rotatory Instability of the Elbow

PURPOSE To evaluate radiographic signs of posterolateral rotatory instability (PLRI) on magnetic resonance imaging (MRI). The goal was to establish objective radiographic criteria to aid in the diagnosis of PLRI. METHODS The MRI scans of 60 patients were evaluated retrospectively. Two study groups were compared. Group 1 (n = 30) consisted of unstable elbows in which PLRI was confirmed by clinical examination and arthroscopy. Group 2 (stable; n = 30) served as the control group. Patients in group 2 had transient epicondylitis without clinical suspicion of instability. Joint incongruity was analyzed for sagittal views through the radial head and the coronoid tip and for coronal and axial views. Interobserver and intra-observer reliability were evaluated. RESULTS In the sagittal view through the radial head, average radiocapitellar incongruity differed significantly between groups 1 and 2. In addition, mean ulnohumeral incongruity in an axial view through the motion axis of the distal humerus showed significant differences between groups. Sagittal views through the tip of the coronoid and coronal views did not reveal significant differences in patients with unstable elbows compared with the control group. CONCLUSIONS The current study provides useful MRI criteria indicative of PLRI when combined with physical examination. Cutoff points of 1.2 mm for radiocapitellar incongruity (sagittal view) and 0.7 mm for axial ulnohumeral incongruity (axial view) are suitable to screen for PLRI. Radiocapitellar incongruity greater than 2 mm and axial ulnohumeral incongruity greater than 1 mm are highly suspicious of elbow instability. TYPE OF STUDY/LEVEL OF EVIDENCE Diagnostic IV.

Short-keeled Cemented Tibial Components Show an Increased Risk for Aseptic Loosening

BackgroundThe choice of implant design plays an important role for primary fixation of a TKA. Short-keeled tibial components allow implantation through a smaller approach with less femorotibial subluxation.Questions/purposesThe purpose of this study was to detect early implant failure resulting from aseptic loosening after cemented short-keeled and standard tibial baseplate implantation.MethodsBetween 2008 and 2010, a group of 160 consecutive patients (with 80 standard and with 80 short-keeled tibial trays) received cemented TKAs. At 1-year followup, patients were examined clinically and radiographs were analyzed regarding aspects of radiolucency. The components were divided into five zones on each radiographic view and the measurements of the 10 zones were added.ResultsThe mean sum of radiolucencies was increased significantly with the short-keeled baseplates. In the current study, short-keeled tibial trays revealed a revision rate of 6.3% after 1-year followup. In contrast, none of the standard tibial baseplates were revised.ConclusionsThe implantation of cemented, short-keeled tibial components is linked to an increased rate of early loosening. Therefore, the indication for cemented, short-keeled component implantation should be reviewed.Level of EvidenceLevel III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Do the radial head prosthesis components fit with the anatomical structures of the proximal radioulnar joint

PurposeThe fitting accuracy of radial head components has been investigated in the capitulo-radial joint, and reduced contact after prosthetic replacement of the radial head has been observed. The kinematics of the proximal radioulnar joint (PRUJ) are affected by radial head arthroplasty as well, but have not yet been investigated in this regard.MethodsThe elbow joints of 60 upper extremities of formalin-fixed body donors were disarticulated to obtain a good view of the PRUJ. Each specimen was mounted on the examining table and radial head position in the native PRUJ was assessed in neutral position, full pronation, and full supination. Measurements were repeated after implantation of mono- and bi-polar prostheses.ResultsAnalysis of the distribution of the joint contacts in the compartments showed significant differences after radial head replacement. In comparison to the native joint, after bipolar and monopolar radial head replacement, the physiological shift of the proximal radius was altered.DiscussionThe physiological shift of the joint contact of the radial head from anterior to posterior during forearm rotation that was found in the native joint in our cadaver model was not observed after prosthetic replacement. With higher conformity and physiological kinematic of radial head prostheses, possibly lower shear forces and lower contact pressures would be generated.Clinical relevanceThe tested radial head prostheses do not replicate the physiological kinematics of the radial head. Further development in the prosthesis design has to be made. The meticulous reconstruction of the annular ligament seems to be of importance to increase joint contact.

Endoprothetik der akuten Radiuskopffraktur

Radial head arthroplasty is the treatment of choice for non-reconstructble radial head fractures. Solid prostheses made of metal or pyocarbon can restore valgus stability of the elbow independent of design or stem fixation. Short-term and mid-term results show mostly good to excellent results without any evident differences between the different prosthesis philosophies. In order to obtain good results it is important to implant the prosthesis correctly without overfilling and to judge concomitant ligament injuries correctly. This article discusses the anatomical and biomechanical basis of radial head arthroplasty as well as the surgical technique and radiological diagnosis of overfilling.ZusammenfassungDie Radiuskopfprothese stellt die Therapie der Wahl für nicht rekonstruierbare Radiuskopffrakturen dar. Solide Prothesen aus Metall oder Pyocarbon können unabhängig vom Design oder Verankerungsoptionen die Valgusstabilität des Ellenbogens wiederherstellen. Kurz- und mittelfristige Ergebnisse zeigen überwiegend gute und sehr gute Ergebnisse, ohne dass bisher wesentliche Unterschiede zwischen den verschiedenen Prothesenphilosophien ausgemacht werden können. Wichtig für das Erreichen eines guten Ergebnisses sind die korrekte Implantationstechnik unter Vermeidung eines „Overstuffing“ und die korrekte Einschätzung der ligamentären Begleitverletzungen. Dieser Artikel diskutiert die anatomischen und biomechanischen Grundlagen der Radiuskopfendoprothetik, die Operationstechnik und die radiologische Diagnostik des „Overstuffing“.AbstractRadial head arthroplasty is the treatment of choice for non-reconstructble radial head fractures. Solid prostheses made of metal or pyocarbon can restore valgus stability of the elbow independent of design or stem fixation. Short-term and mid-term results show mostly good to excellent results without any evident differences between the different prosthesis philosophies. In ordert to obtain good results it is important to implant the prosthesis correctly without overfilling and to judge concomitant ligament injuries correctly. This article discusses the anatomical and biomechanical basis of radial head arthroplasty as well as the surgical technique and radiological diagnosis of overfilling.

Treatment of radial head and neck fractures: in favor of anatomical reconstruction

Radial head fractures represent the most common elbow fractures. Undisplaced fractures usually occur in isolation and can be treated nonsurgically. Displaced fractures should be treated surgically. Simple two-part fractures can easily be handled by osteosynthesis, but comminuted fractures pose a major problem for reconstruction. As the radial head is an important stabilizer of the elbow joint—especially in the context of concomitant ligamentous injuries—its resection may lead to pain, limited range of motion, and instability. Therefore, radial head resection is not recommended for the acute situation and open reduction internal fixation (ORIF) or prosthetic replacement should be aimed for. Complications such as secondary loss of fixation, radial head necrosis, and nonunion due to insufficient stability of the osteosynthesis have often been described. Therefore, prosthetic replacement is recommended if stable reconstruction is impossible. With the development of new locking plates especially designed for the maintenance of radial head fractures, the indications for osteosynthesis may be extended. As radial head fractures are complicated by a high percentage of ligamentous injuries and concomitant elbow fractures such as the coronoid, capitellum, and proximal ulna, these additional injuries have to be taken into account. The current treatment concepts are discussed within this paper.

Morphology of the proximal and middle phalanx of fingers with regard to the Ascension PyroCarbon PIP total joint

The Ascension PyroCarbon prosthesis has been used in proximal interphalangeal joint osteoarthritis. The dimensions of the intramedullary distal metadiaphyseal canal (isthmus) of the proximal phalanx and the base of the middle phalanx of cadaver fingers were investigated radiographically (n = 304) and macroscopically (n = 152). In up to 30% of the phalanges, the isthmus was smaller than the stem of the smallest proximal component size. The distal component head was always smaller than the middle phalanx base. Insertion and success of the Ascension PyroCarbon prosthesis is strongly dependent on bone morphology. A critical examination of the isthmus in radiographs is recommended in planning. If the isthmus is clearly smaller than the smallest proximal component, insertion of the prosthesis could be inadvisable. A clear mismatch between the distal component and the middle phalanx base should be avoided due to the potential risk for late subsidence and failure of the prosthesis.

[Anatomic relationship between the pronator quadratus and brachioradialis muscle insertion: implications for repair of the muscle after volar plate fixation of distal radius fractures].

BACKGROUND In open reduction and volar plate fixation of distal radius fractures, the pronator quadratus (PQ) muscle is usually detached at the radial edge of the distal radius. Repair of the muscle is reasonable for coverage of the plate and to maintain normal pronation of the forearm. However, repair of the muscle is not always satisfactory. In this study, the topographic relationship of both the PQ and the brachioradialis muscle (BR) insertions are investigated with regard to optimising the repair of the PQ in open reduction and volar plate fixation of distal radius fractures. MATERIALS AND METHODS Twelve forearm pairs fixed in formalin were examined. The muscular boundaries of the PQ and the insertion of the BR were dissected, photographs were taken and measured digitally. RESULTS The average distance of the PQ insertion was 4.75 cm. Distally, a close topographic relationship exists between the insertions of both the PQ and BR. A fascial connection of both muscles was detected in all specimens. The average distance of the common insertion was 1.75 cm. After removal of the PQ fascia, 0.85 cm of common insertion remained. In 25 % a muscular connection between both the PQ and BR was detected after removal of the PQ fascia. CONCLUSION Both the PQ and BR have a common connective tissue and partially a common muscular insertion. Detaching the PQ insertion with a part of the BR insertion in open reduction and volar plate fixation of distal radius fractures can presumably lead to a more stable repair of the PQ in contrast to a repair within the muscle.

Endoprosthetics of acute radial head fractures

Radial head arthroplasty is the treatment of choice for non-reconstructble radial head fractures. Solid prostheses made of metal or pyocarbon can restore valgus stability of the elbow independent of design or stem fixation. Short-term and mid-term results show mostly good to excellent results without any evident differences between the different prosthesis philosophies. In order to obtain good results it is important to implant the prosthesis correctly without overfilling and to judge concomitant ligament injuries correctly. This article discusses the anatomical and biomechanical basis of radial head arthroplasty as well as the surgical technique and radiological diagnosis of overfilling.ZusammenfassungDie Radiuskopfprothese stellt die Therapie der Wahl für nicht rekonstruierbare Radiuskopffrakturen dar. Solide Prothesen aus Metall oder Pyocarbon können unabhängig vom Design oder Verankerungsoptionen die Valgusstabilität des Ellenbogens wiederherstellen. Kurz- und mittelfristige Ergebnisse zeigen überwiegend gute und sehr gute Ergebnisse, ohne dass bisher wesentliche Unterschiede zwischen den verschiedenen Prothesenphilosophien ausgemacht werden können. Wichtig für das Erreichen eines guten Ergebnisses sind die korrekte Implantationstechnik unter Vermeidung eines „Overstuffing“ und die korrekte Einschätzung der ligamentären Begleitverletzungen. Dieser Artikel diskutiert die anatomischen und biomechanischen Grundlagen der Radiuskopfendoprothetik, die Operationstechnik und die radiologische Diagnostik des „Overstuffing“.AbstractRadial head arthroplasty is the treatment of choice for non-reconstructble radial head fractures. Solid prostheses made of metal or pyocarbon can restore valgus stability of the elbow independent of design or stem fixation. Short-term and mid-term results show mostly good to excellent results without any evident differences between the different prosthesis philosophies. In ordert to obtain good results it is important to implant the prosthesis correctly without overfilling and to judge concomitant ligament injuries correctly. This article discusses the anatomical and biomechanical basis of radial head arthroplasty as well as the surgical technique and radiological diagnosis of overfilling.

Endoprothetik des Ellenbogengelenks – Implantation am Beispiel der Latitude-Prothese (Tornier)

Due to technical progress, the indication for total elbow arthroplasty could be expanded in recent years. As a result, the demand regarding functionality and mobility of the replaced joint has risen as well. Elbow arthroplasty has to be considered as technically demanding. Only with detailed knowledge of this surgical procedure and its possible intraoperative pitfalls can one provide the best possible results. In this instructional video we explain the implantation of the Latitude elbow prosthesis (Tornier) putting emphasis on the correct approach as well as implantation of the prosthesis and subsequent wound closure.

Die anatomische Rekonstruktion des Hüftgelenks: ein Vergleich von Kurz- und Standardschaft

BACKGROUND Currently, short cementless femoral stems are alternative implants to treat osteoarthritis in young patients with sufficient bone quality in order to get a more proximal load transfer. The purpose of the present study was to biomechanically compare joint reconstructions resulting from implantations of a short-stemmed and a conventional hip replacement. METHODS 100 patients (50 short-stemmed and 50 conventional) were retrospectively examined. For evaluation of biomechanical parameters standardised pre- and postoperative X-rays (pelvic AP views) were used and digitally analysed. RESULTS The horizontal femoral off-set increased within both groups (short: 2.0 mm and conventional: 3.3 mm), with a significant increase in the conventional group. The hip centre of rotation was significantly medialised after both procedures (short: 6.0 mm and conventional: 4.2 mm). Limb length was shorter preoperatively at the arthroplasty side, but increased thereafter (short: 2.1 mm and conventional: 2.6 mm). Compared to the native contralateral side the limb length was almost equal after THA (short: 0.7 mm and conventional: 0.8 mm). CONCLUSIONS Our study shows that an almost anatomic reconstruction of hip joint biomechanics is possible with a short-stemmed prosthesis compared to a conventional stem, regarding limb length, centre of rotation and offset.