Martin Henri Hessmann

Mid- to long-term results after bipolar radial head arthroplasty

BACKGROUND Radial head arthroplasty is considered the treatment of choice for unreconstructable radial head fractures in the acute fracture situation. Although short-term results in the current literature are promising, replacement of the radial head remains controversial as long-term results are still missing. We report our 8.8-year results after treatment with a bipolar radial head prosthesis by Judet. MATERIALS AND METHODS In our department, 19 patients were treated with bipolar radial head arthroplasty between 1997 and 2001. Seventeen of these patients-14 men and 3 women-were examined retrospectively after 106 months (range, 78-139). Of these, 9 patients were treated primarily, 7 patients secondarily, and 1 because of a tumor. RESULTS On the Mayo Elbow Performance Score, 6 patients achieved excellent results, 10 good, and one fair. The mean DASH score was 9.8 (range, 0-34). No differences were seen between primary and secondary implantation. Flexion averaged 124° (range, 110-150°), the extension deficit was 21° (range, 0-40°), pronation 64° (range, 30-90°), and supination 64° (range, 30-90°). The following complications were seen: 2 dislocations and 8 cases of degenerative changes of the capitellum, 1 with severe erosion. Signs of ulnohumeral arthrosis were found in 12 patients. No evidence of loosening, radiolucencies, or proximal bone resorption was detected. CONCLUSION Despite major primary complications and high incidence of radiographic signs of degenerative changes after 8.8 years, mainly good clinical results were achieved with Judets bipolar prosthesis.

Osteosynthesetechniken bei proximalen Humerusfrakturen

Abstract. Although proximal humeral fractures are common injuries, there is no generally accepted strategy as to how unstable and displaced two- to four-part fractures should be managed. Surgical therapy is in a conflicting situation between the requirement for anatomical fracture reduction and stable fixation, on the one hand, and the necesscity for minimal intraoperative damage to the soft tissue and arterial vascularization of the humeral head in order to avoid avascular necrosis on the other. Whereas minimally invasive procedures using closed or percutaneous reduction and fixation techniques are advantageous for protection of the arterial blood supply of the proximal humerus, plate fixation provides superior fixation stability. Plate fixation seems to be associated with a reduced risk of avascular necrosis when indirect reduction techniques are used. Poor results in the operative management of humeral head fractures are often seen in association with malunion. There is therefore a tendency towards the use of implants with angular stability in order to reduce the risk for secondary loss of reduction during functional aftertreatment. Innovative new plates and intramedullary nails that provide superior stability of fixation of the humeral head fragment have been actually introduced into clinical practice. Together with the specific patient and fracture characteristics, the final result of operative management, however, remains mainly related to the knowledge and operative skills of the trauma or orthopaedic surgeon who deals with these proximal humeral fractures.Zusammenfassung. Proximale Humerusfrakturen sind häufige Verletzungen. Die Frage der optimalen osteosynthetischen Behandlung instabiler und dislozierter 2- bis 4-Segmentfrakturen ist nach wie vor nicht einhellig geklärt. Die operative Therapie befindet sich in der Konfliktsituation zwischen der Forderung einer anatomischen Reposition und stabilen Frakturretention auf der einen Seite und der Notwendigkeit einer maximalen intraoperativen Schonung der periglenohumeralen Weichteilstrukturen und Blutversorgung des Oberarmkopfs, mit dem Ziel das iatrogene Risiko der avasculären Kopfnekrose zu minimieren, andererseits. Während Minimalosteosynthesen, bei denen die Reposition indirekt oder percutan erfolgt, Vorteile bezüglich einer geringen Weichteiltraumatisierung bieten, gewährleistet die Plattenosteosynthese in der Regel eine bessere Stabilität. Allerdings ist vielmehr als das Implantat an sich die operative Technik der Reposition und Retention für ein erhöhtes Kopfnekroserisiko verantwortlich, so dass durch Anwendung indirekter Repositionstechniken auch mit der Plattenosteosynthese weniger Kopfnekrosen gesehen werden.Schlechte Ergebnisse stehen oftmals mit einer nicht ausreichenden Frakturreposition in Zusammenhang. Aus diesem Grund besteht eine zunehmende Tendenz zur Verwendung winkelstabiler Implantate, von denen erhofft wird, dass sie bei besserer Stabilität insbesondere das Risiko sekundärer Korrekturverluste reduzieren. Weitere technische Neuerungen beinhalten die Entwicklung winkelstabiler Marknägel, welche speziell für die Versorgung proximaler Humerusfrakturen konzipiert werden.Osteosynthesen am proximalen Humerus erleben somit derzeit einen Umbruch, was die Entwicklung neuer Operationsmethoden und Implantaten anbetrifft. Dennoch bleiben neben Charakteristiken der Verletzung an sich vor allem Einsicht des Chirurgen in der Behandlung proximaler Humerusfrakturen ebenso wie die individuelle Handhabung der verschiedenen zur Verfügung stehenden Techniken für das funktionelle Endergebnis im Einzelfall entscheidend.

Extracorporeal shock wave-mediated changes in proliferation, differentiation, and gene expression of human osteoblasts.

BACKGROUND The goal of this study was to determine whether cell proliferation, differentiation, and gene expression of primary human osteoblasts (hOB) are influenced by shock wave application (SWA). METHODS Osteoblast cultures were isolated from cancellous bone fragments and treated with 500 impulses of energy flux densities of 0.06 mJ/mm, 0.18 mJ/mm, 0.36 mJ/mm, and 0.50 mJ/mm. Twenty-four hours and 96 hours after SWA cell proliferation, alkaline phosphatase activity, and mineralization were analyzed. The global gene expression profiling was determined 96 hours after SWA employing Affymetrix HG-U133A microarrays. RESULTS After 24 hours, hOB showed a dose-dependent increase in cell proliferation from 68.7% (at 0.06 mJ/mm, p = 0.002) up to 81.6% (at 0.5 mJ/mm, p = 0.001), which also persisted after 96 hours. Numbers of alkaline phosphatase-positive hOB increased after SWA treatment with peak levels of response between 0.18 mJ/mm and 0.5 mJ/mm after 24 hours. Mineralization was significantly higher in all groups compared with controls. Microarray analyses revealed SWA-induced differential expression of 94 genes involved in physiologic processes, cell homeostasis, and bone formation. Most intriguing was the up-regulation of multiple genes involved in skeletal development and osteoblast differentiation (e.g., PTHrP, prostaglandin E2-receptor EP3, BMP-2 inducible kinase, chordin, cartilage oligomeric matrix protein, matrillin). CONCLUSION We showed that shock waves have direct dose-dependent stimulatory effects on proliferation and differentiation of osteoblasts from normal human cancellous bone. We demonstrated that several genes critical for osteoblast differentiation and function are regulated after SWA. Overall, data presented herein will aid further understanding of the osteogenic effect of shock waves and, in addition, will enhance current knowledge of the SWA-mediated gene expression.

Cell viability, osteoblast differentiation, and gene expression are altered in human osteoblasts from hypertrophic fracture non-unions

Recent studies have provided evidence that the number and proliferation capacity of bone marrow-derived mesenchymal stem cells, as well as the number of osteoprogenitor cells are reduced in patients with fracture non-unions. For fracture non-unions that do not heal after appropriate surgical intervention, the question arises as to what extent systemic cellular dysfunctions should be considered as being pathogenetic factors. For this purpose, we have examined the hypothesis that the cell function of osteoblasts isolated from patients with fracture non-unions may differ from those of normal control individuals in an identical and controlled in vitro situation. We analyzed the osteoblast cell viability, formation of alkaline phosphatase-positive (CFU-ALP) and mineralization-positive (CFU-M) colony forming units, as well as global differences of gene expression in osteoblasts from patients with fracture non-unions and from control individuals. We found that cell viability and CFU-M-formation were significantly reduced in non-union osteoblasts. This was accompanied by significant differences in osteoblast gene expression as revealed by Affymetrix-microarray analysis and RT-PCR. We identified a set of significantly down-regulated factors in non-union osteoblasts that are involved in regulation of osteoblast proliferation and differentiation processes (canonical Wnt-, IGF-, TGF-beta-, and FGF-signaling pathways). The results of the present study strongly support the hypothesis that cell viability, differentiation, and gene expression of osteoblasts may be altered in patients who develop recurrent and recalcitrant fracture non-unions. Proteins involved in Wnt-, IGF, TGF-beta-, and FGF-signaling pathways may be of particular interest and may unveil new potential therapies.

Internal Fixation of Proximal Humeral Fractures: Current Concepts

AbstractFractures of the proximal humerus are an increasingly common type of injury. Mainly elderly patients with osteoporotic bone are affected. Whereas non-displaced and stable fractures are managed successfully with conservative treatment, there is no general agreement on the surgical strategy for displaced and unstable two- to four-part fractures. The clinical outcome is influenced by the fracture type and concomitant injury to the rotator cuff. Extensive surgical manipulation of the soft tissues, non-anatomic and/or unstable fixation as well as technical errors are important contributing factors to poor clinical results.Goals of surgical treatment are to restore anatomy, to achieve fixation that is stable enough to allow early mobilization, to avoid secondary displacement and not to harm the blood supply of the humeral head in order to minimize the risk for avascular necrosis.Minimally invasive procedures using closed reduction are advantageous for protection of the arterial blood supply. Plate fixation offers superior biomechanical stability. There is a recent tendency to use fixedangle implants for proximal humeral fractures in order to avoid secondary loss of fixation. Locked plates acting as internal fixator as well as intramedullary nails better adapt according to the biomechanical and anatomical characteristics of the proximal humerus. First clinical experience with those implants is encouraging but they do not compensate for an insufficient surgical technique.

Intramedullary Stabilization of Extraarticular Proximal Tibial Fractures : A Biomechanical Comparison of Intramedullary and Extramedullary Implants Including a New Proximal Tibia Nail (PTN)

Objectives: To determine in the laboratory whether there are or are not differences between individual geometrical designs of intramedullary and extramedullary devices used for the fixation of extraarticular proximal tibial fractures. Methods: Five devices were tested: a newly developed Proximal Tibia Nail (PTN), conventional double-plate osteosynthesis (DPO), the Less Invasive Stabilization System (LISS), an augmented Unreamed Tibial Nail with a T-stabilization-plate (UTN + TSP), and an external fixator (ExFix). A 10-mm defect osteotomy was performed on paired human tibiae, and the proximal and distal ends were potted in polymethylmethacrylate cement (PMMA). Each pair of bones was randomly stabilized with the new PTN in 1 tibia (Groups PTN1 through PTN4) and in 1 of the 4 comparative implants in the corresponding contralateral bone. A biomechanical test of the bone implant construct was then performed with a vertical axial force of 350, 600, and 900 N, a bending moment of 6 Nm and a bidirectional rotational strain of 8 Nm. Displacement of bone fragments was measured and depicted as a force-displacement diagram. Results: For axial loading, significant differences were seen between the PTN 2 group compared to the LISS group (P = 0.016) and the PTN 4 group compared to the ExFix group (P = 0.016). No statistically significant differences were seen for the PTN 1 group compared to the DPO group (P = 0.125) and the PTN 3 group compared to the UTN + TSP group (P = 0.453). The bending stiffness of the PTN 1-4 groups was not significantly different from any of the 4 alternative implants. There was comparable torsional stiffness in all implant groups except for the UTN + TSP group, which was less stable and significantly different from the PTN 3 group (P = 0.016). Conclusions: Given the parameters of this investigation, the new PTN would theoretically provide the same mechanical stability as the DPO in axial loading. Higher stability in axial loading may be present when compared to the LISS or the ExFix. Further clinical investigation of this implant will determine its usefulness among proximal tibial fixation devices.

Radiation exposure in whole-body computed tomography of multiple trauma patients: bearing devices and patient positioning.

BACKGROUND Whole-body computed tomography (WBCT) plays an important role in the management of severely injured patients. We evaluated the radiation exposure of WBCT scans using different positioning boards and arm positions. METHODS In this retrospective study, the radiation exposure of WBCT using a 16-slice multislice computed tomography scanner was evaluated. Individual effective doses (E, mSV) was calculated. Patients were assigned to two groups according to placement on a plastic transfer mat (PTM, group 1) or on the Trauma Transfer™-Board (TTB, group 2). Data were collected for each group with arm placement on the abdomen (a) or in raising position (b), respectively. The maximum ventro-dorsal diameter [VDD] at the trunk was measured. RESULTS 100 patients with potentially life-threatening injuries were analysed. Patient demographics and VDD did not differ in the two groups. Radiation exposure in term of E did not reveal any significant differences between the two positioning boards using same arm position [group 1a (n=26) vs. 2a (n=24) (mSV): 16.7±4.7 vs. 17.1±4.4, group 1b (n=26) vs. 2b (n=24) (mSV): 13.1±3.9 vs. 14.3±1.5]. The arm raising positioning showed a significant reduction in E in comparison to the placement on abdomen position [group 1b vs. 1a (mSV): 13.1±3.9 vs. 16.7±4.7, p<0.05, group 2b vs. 2a (mSV): 14.3±1.5 vs. 17.1±4.4, p<0.05]. CONCLUSIONS Patient arm positioning for WBCT has an important influence on radiation exposure. Effective dose was 16-22% lower when arms were raised. An individual placement algorithm may lead to a relevant reduction of radiation exposure of severely injured patients.

The Benefit of Multislice Computed Tomography in the Emergency Room Management of Polytraumatized Patients

AbstractReducing time requirements for the primary diagnostic evaluation is a major concern in the early phase of polytrauma management. Multislice computed tomography (MSCT) is a quick and reliable method for the initial diagnostic evaluation. CT provides more detailed and more consistent information than conventional radiography and it has the great advantage of allowing rapid examination of the head, vertebral column, chest, abdomen, and pelvis during one single examination. The CT suite needs to be adequately equipped for resuscitation and reanimation, which is done parallel to the radiologic investigations.Since polytrauma management is based on a multidisciplinary approach that is characterized by a coordinated interaction between trauma surgeons, anesthesiologists and radiologists, members of all involved disciplines need adequate teaching. Guidelines and algorithms contribute to optimize the early management.

Management of Acute Hemorrhage in Pelvic Trauma: An Overview.

Pelvic disruption is a combination of fractures or dislocations of the pelvic ring with trauma of the soft tissues on the inside and outside of this ring. Hemodynamic instability is the result of blood loss out of the fracture fragments, the posterior venous plexus, ruptured pelvic organs, or arterial lesions. In the resuscitation phase, different measures are possible to reduce the volume of the disrupted pelvis and to restore mechanical stability. They are not competitive but complementary. Pelvic binders should be used in the prehospital phase before and during transport. Application of a pelvic C-clamp is restricted to inhospital patients with C-type pelvic ring lesions and with severe and ongoing hemodynamic instability. External fixation is most useful in B-type but also has limited value in C-type injuries. The prerequisite for pelvic packing is the restoration of mechanical stability by pelvic C-clamping or external fixation. It is effective in severe venous bleeding in the small pelvis. Pelvic angiography and selective embolization is performed in patients with active arterial bleeding. These patients can be identified by a convincing clinical picture, by early multislice computed tomography (CT) with contrast- enhanced angiographic technique, or by the persistent need for volume replacement after C-clamping, external fixation, or pelvic packing.

Is the Posterior Wall Avulsion the Simplest Acetabular Fracture

The posterior wall fracture – the most frequent acetabular lesion – is often regarded as the simplest acetabular fracture. In fact, a large variety of complex articular lesions is subsumed under this fracture type.A consecutive series of 60 posterior wall fractures is reviewed retrospectively. Lesions characteristics, treatment method, early and late postoperative complications a 2-year functional results were recorded.In 27 patients (45%), additional damage to the cartilage of the acetabular cavitiy such as subchondral impaction, free articular fragments of separation of the posterior wall into several pieces was present. Seven patients (11.6%) showed preoperative neurologic deficit. Secondary nerve damage was present in 8.3%. During the first 2 years, additional surgery was performed in 7/46 patients (15.2%). The rate of periarticular ossifications amounted to 26.1%. The rate of excellent and good results was 69.5%.Posterior wall fracture of the acetabulum is a more complex injury than generally accepted. The trauma surgeons task is to complete identify the lesion and to consider all aspects of the injury during surgery and rehabilitation. Even in experienced hand, excellent and good long-term results will not excee 75%. Poor results are due to the difficulty of posterior wall reconstruction, partial osteonecrosis and/or complications caused by the Kocher-Langenbeck approach.