Pol Maria Rommens

The effect of human osteoblasts on proliferation and neo-vessel formation of human umbilical vein endothelial cells in a long-term 3D co-culture on polyurethane scaffolds.

Angiogenesis is a key element in early wound healing and is considered important for tissue regeneration and for directing inflammatory cells to the wound site. The improvement of vascularization by implementation of endothelial cells or angiogenic growth factors may represent a key solution for engineering bone constructs of large size. In this study, we describe a long-term culture environment that supports the survival, proliferation, and in vitro vasculogenesis of human umbilical vein endothelial cells (HUVEC). This condition can be achieved in a co-culture model of HUVEC and primary human osteoblasts (hOB) employing polyurethane scaffolds and platelet-rich plasma in a static microenvironment. We clearly show that hOB support cell proliferation and spontaneous formation of multiple tube-like structures by HUVEC that were positive for the endothelial cell markers CD31 and vWF. In contrast, in a monoculture, most HUVEC neither proliferated nor formed any apparent vessel-like structures. Immunohistochemistry and quantitative PCR analyses of gene expression revealed that cell differentiation of hOB and HUVEC was stable in long-term co-culture. The three-dimensional, FCS-free co-culture system could provide a new basis for the development of complex tissue engineered constructs with a high regeneration and vascularization capacity.

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.

Comprehensive classification of fragility fractures of the pelvic ring: Recommendations for surgical treatment

Due to the increasing life expectancy, orthopaedic surgeons are more and more often confronted with fragility fractures of the pelvis (FFPs). These kinds of fractures are the result of a low-energy impact or they may even occur spontaneously in patients with severe osteoporosis. Due to some distinct differences, the established classifications for pelvic ring lesions in younger adults do not fully reflect the clinical and morphological criteria of FFPs. Most FFPs are minimally displaced and do not require surgical therapy. However, in some patients, an insidious progress of bone damage leads to increasing displacement, nonunion and persisting instability. Therefore, new concepts for surgical treatment have to be developed to address the functional needs of the elderly patients. Based on an analysis of 245 consecutive patients with FFPs, we propose a novel classification system for this condition. This classification is based on morphological criteria and it corresponds with the degree of instability. Also in the elderly, these criteria are the most important for the decision on the type of treatment as well as type and extent of surgery. The estimation of the degree of instability is based on radiological and clinical findings. The classification gives also hints for treatment strategies, which may vary between minimally invasive techniques and complex surgical reconstructions.

Survival trends and predictors of mortality in severe pelvic trauma: Estimates from the German Pelvic Trauma Registry Initiative

STUDY OBJECTIVE To determine longitudinal trends in mortality, and the contribution of specific injury characteristics and treatment modalities to the risk of a fatal outcome after severe and complex pelvic trauma. METHODS We studied 5048 patients with pelvic ring fractures enrolled in the German Pelvic Trauma Registry Initiative between 1991 and 1993, 1998 and 2000, and 2004 and 2006. Complete datasets were available for 5014 cases, including 508 complex injuries, defined as unstable fractures with severe peri-pelvic soft tissue and organ laceration. Multivariable mixed-effects logistic regression analysis was employed to evaluate the impact of demographic, injury- and treatment-associated variables on all-cause in-hospital mortality. RESULTS All-cause in-hospital mortality declined from 8% (39/466) in 1991 to 5% (33/638) in 2006. Controlling for age, Injury Severity Score, pelvic vessel injury, the need for emergency laparotomy, and application of a pelvic clamp, the odds ratio (OR) per annum was 0.94 (95% confidence interval [CI] 0.91-0.96). However, the risk of death did not decrease significantly in patients with complex injuries (OR 0.98, 95% CI 0.93-1.03). Raw mortality associated with this type of injury was 18% (95% CI 9-32%) in 2006. CONCLUSION In contrast to an overall decline in trauma mortality, complex pelvic ring injuries remain associated with a significant risk of death. Awareness of this potentially life-threatening condition should be increased amongst trauma care professionals, and early management protocols need to be implemented to improve the survival prognosis.

Primäre totale Ellenbogenprothese zur Versorgung distaler Humerusfrakturen Primary Total Elbow Replacement for Fractures of the Distal Humerus

ZusammenfassungOperationszielErreichen einer stabilen und schmerzfreien Funktion durch primäre Implantation einer totalen Ellenbogenprothese bei komplexen intraartikulären distalen Humerusfrakturen älterer Patienten.IndikationenFraktur mit freien Fragmenten oder schlechter Knochenqualität, die eine stabile Osteosynthese nicht zulassen. Geschlossene, komplexe intraartikuläre distale Humerusfraktur (Typ C nach der AO-Klassifikation).Typ-A- und B-Fraktur des distalen Humerus bei Patienten mit vorbestehenden degenerativen Veränderungen, rheumatoiden Erkrankungen oder Voroperationen des Gelenks. Gute Mitarbeit des Patienten, geringer Funktionsanspruch, Patientenalter > 65 Jahre.KontraindikationenOffene Frakturen (Typ II oder III nach Gustilo-Anderson).Infizierte Wundverhältnisse, offene Weichteilverletzungen.Fehlende Mitarbeit des Patienten, hoher Funktionalitätsanspruch, Patientenalter > 65 Jahre.Paralyse des Bizepsmuskels.OperationstechnikRückenlagerung des Patienten. Dorsaler Zugang zum Ellenbogengelenk. Darstellen der medialen Anteile des Musculus triceps an der Insertion des dorsalen Humerus und der Gelenkkapsel, Abdrängen in Kontinuität mit dem ulnaren Periost und der Unterarmfaszie. Bei Entfernung des frakturierten distalen Anteils des Humerus kann der Ansatz des Musculus triceps belassen werden. Vorbereitung des Humerusschafts: Bei mehrfach frakturierten Kondylen ist eine Rekonstruktion nicht notwendig; intramedulläres Entfernen des Knochens von der medialen und lateralen suprakondylären Kante mit einer Fräse. Entfernen der Olekranonspitze. Knochenspananlagerung hinter der anterioren Lasche der humeralen Komponente. Einzementieren der humeralen und ulnaren Komponente. Nachresektion des Radiuskopfes bzw. Processus coronoideus bei Impingement der Gelenkfacetten. Transossäre Reinsertion des Musculus triceps am Olekranon.WeiterbehandlungSelbständige Bewegungsübungen. Vermeidung des Hebens von Gewichten > 5 kg, keine wiederholten Dauerbelastungen > 1 kg Gewicht und keine forcierten Bewegungen im Ellenbogengelenk, z. B. Schlagsportarten.Ergebnisse49 Totalendoprothesen wurden bei 48 Patienten (Durchschnittsalter 67 Jahre) aufgrund distaler Humerusfrakturen eingesetzt. 43 Frakturen konnten nach einem Zeitraum von 7 Jahren nachuntersucht werden. Nach der AO-Klassifikation wurden fünf Typ- A , fünf Typ-B und 33 Typ-C Frakturen behandelt. Der durchschnittliche Bewegungsumfang lag zwischen 24° und 131°. Der „Mayo Elbow Performance Score“ betrug durchschnittlich 93.Die Komplikationen aller 49 Patienten wurden anhand der Akten erfasst. 32-mal bestanden im Verlauf keine Komplikationen. Insgesamt mussten zehn Revisionseingriffe durchgeführt werden, fünfmal war im Verlauf eine Revisionsarthroplastie erforderlich.Retrospektiv kann die Totalendoprothese des Ellenbogens in der Versorgung distaler Humerustrümmerfrakturen unter strenger Berücksichtigung der genannten Indikationen empfohlen werden.AbstractObjectiveAchieving stability and pain-free function for osteoporotic intraarticular multifragmentary fractures of the distal humerus in elderly patients by primary total elbow replacement (TER).IndicationsNon-soft-tissue-attached fragments, poor-quality bone, where stable osteosynthesis is not attainable.Severely comminuted intraarticular closed type C fractures according to the AO classification with multiple small bone/cartilage fragments.In case of degenerative joint diseases and/or previous surgery in rheumatoid patients also type A and B fractures. High compliance, low demand, and old patient > 65 years.ContraindicationsType II or III Gustilo-Anderson open fractures (primary irrigation and debridement).Preexisting infection, open wounds.Younger, high-demand or noncompliant patient.Paralysis of the biceps muscle.Surgical TechniqueSupine positioning of patient. Triceps-sparing dorsal approach. Elevation of medial aspect of the triceps from posterior aspect of the humerus and capsula, reflecting the triceps in continuity with the ulnar periosteum and the forearm fascia. If removal of distal part of the humerus, the triceps insertion can be left intact. Preparation of humerus: no reconstruction of multifractured condyles; excavate bone from medial and lateral supracondylar ridges with burr. Preparation of ulna: remove tip of olecranon. Cemented humeral and ulnar components. Bone graft interposition behind anterior flange of humeral component. Resection of radial head and coronoid process, if impingement after trial reduction. Triceps reattachment transosseous through olecranon.Postoperative ManagementNo formal physical-therapy sessions. Avoid single-event weight lifting of > 5 kg and repetitive lifting of > 1 kg. Discourage playing racquets sports.Results49 acute distal humeral fractures in 48 patients (average age: 67 years) were treated with TER. 43 fractures were followed at an average of 7 years. According to the AO classification, five fractures were type A, five type B, and 33 type C. The average flexion arc at follow-up was 24–131°, the Mayo Elbow Performance Score averaged 93.Data of complications were obtained from records in all 49 patients. 32 of the 49 elbows had neither a complication nor any further surgery from the time of the index arthroplasty to the most recent follow-up evaluation. Ten additional operative procedures, including five revision arthroplasties, were required.The retrospective review supports recommendation for TER for the treatment of an acute distal humeral fracture, when strict inclusion criteria are observed.

Treatment of Unstable Peritrochanteric Fractures in Elderly Patients with a Compression Hip Screw or with the Vandeputte (vdp) Endoprosthesis: A Prospective Randomized Study

Summary: A prospective randomized study was set up, comparing a compression hip screw with the Vandeputte (VDP) endoprosthesis treatment for fresh, unstable peritrochanteric fractures, according to the Evans-Jensen and AO systems. Ninety patients, ages ≥70 years, 47 of whom were treated with a compression hip screw and 43 with a VDP endoprosthesis, were included. All patients were being followed for 3 months. No difference between the two groups was found for operating time, wound complications, and mortality rate, but there was a higher transfusion need in VDP treatment. Severe fracture redisplacement or total collapse of the fracture occurred in 11 (26%) compression hip screw patients, two of whom had revision surgery. Only one patient needed reintervention after VDP treatment. Functional capacity of preoperative independent patients at hospital discharge did not differ for the two groups. In conclusion, the compression hip screw seemed to be an appropriate implant for most of the peritrochanteric fractures, but for very old patients with advanced osteoporosis, with a complex, unstable peritrochanteric fracture, and who are eligible for early mobilization, primary cemented endoprosthesis might be the best treatment

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.

Clinical performance of a new medullary humeral nail: antegrade versus retrograde insertion.

Objective A new intramedullary nail system for humeral shaft fractures is evaluated to determine whether retrograde nailing is as reliable as antegrade nailing. Study Design Prospective multicenter nonrandomized clinical study. Patients Eighty-four patients with acute humeral shaft fractures were nailed with the new unreamed humeral nail (UHN) system. Fifty-seven nails were introduced retrogradely, and twenty-seven antegradely. Bone healing and functional outcome were the follow-up parameters. Results The ratio of perioperative complications was equivalent for both groups, but one shaft fracture and three fractures or fissures at the entry point occurred in the group with retrograde nail insertion. Five fractures, all with retrograde nail insertion, needed secondary surgery to achieve bony healing. There was no difference in functional outcome after healing in either group. Conclusion Retrograde nailing of humeral shaft fractures is technically more demanding than antegrade nailing. Fractures or fissures at the insertion point must be avoided by adequate preparation of the entry hole and careful nail insertion. Bone healing problems seem more surgeon-related than approach-related. As in every other procedure, an optimal fracture configuration and high fracture stability must be achieved.

Number and Locations of Screw Fixation for Volar Fixed-Angle Plating of Distal Radius Fractures: Biomechanical Study

PURPOSE To compare the biomechanical properties of different numbers and locations of screws in a multidirectional volar fixed-angle plate in a distal radius osteotomy cadaver model. METHODS We created an extra-articular fracture in 16 pairs of fresh-frozen human cadaver radiuses. The 32 specimens were randomized into 4 groups. All fractures were fixated with a multidirectional volar fixed-angle plate. We tested 4 different screw-placement options in the distal fragment. The distal fragment was fixed with 4 locking screws in the distal row of the plate in group a, and with 4 locking screws alternately in the distal and proximal rows in group b. In group c, 3 locking screws were used in the proximal row; in group d, 7 locking screws were used, filling all screw holes in the distal and proximal rows of the plate. The proximal fragment was fixed with 3 screws. The specimens were loaded with 80 N under dorsal and volar bending and with 250 N axial loading. Finally, load to failure tests were performed. RESULTS Group d had the highest mean stiffness, 429 N/mm under axial compression, and was statistically significantly stiffer than the other groups. Group b had a mean stiffness of 208 N/mm, followed by group a, with 177 N/mm. Group c showed only a mean stiffness of 83 N/mm under axial compression. There were no statistically significant differences under dorsal and volar bending. CONCLUSIONS In this model of distal radial fractures, there was a difference regarding the stiffness and the placement of screws in the distal rows of a volar fixed-angle plate. Inserting screws in all available holes in the distal fragment offered the highest stability. Using only the proximal row with 3 screws created an unstable situation. Based on these findings, we recommend placing at least 4 screws in the distal fragment and assigning at least 2 screws to the distal row of the multidirectional screw-holes.