Core decompression combined with implantation of a demineralised bone matrix for non-traumatic osteonecrosis of the femoral head.

INTRODUCTION: Core decompression is the standard surgical procedure in the treatment of early stage non-traumatic osteonecrosis of the femoral head (ONFH). However, there is still a debate whether decompression in combination with supplementary augmentation by bone grafts, growth factors, or cell implementation is superior to conventional decompression alone. This study evaluated patients after core decompression combined with an augmentation by a demineralised bone matrix, and particularly aimed to report long-term conversion rates to total hip replacement (THR). MATERIALS AND METHODS: 14 patients with 18 hips suffering from ONFH (Ficat stage I-IIB) underwent this surgical procedure. All patients underwent radiographic and MRI investigations at baseline and at follow-up periods of 12 and 24 months. The clinical follow-up was done using the Merle d'Aubigné-score for an average period of 9 years after surgery. RESULTS: 14 of the 18 subjects (77 %) achieved at least a good clinical result after 2 years. The Merle d'Aubigné-score improved significantly after 12 (p = 0.0001) and 24 months (p = 0.0002). However, the MRI volumetric analysis showed an increased necrotic bone volume from 3.16 ± 0.54 to 3.88 ± 0.62 cm(3) (p = 0.04). Within 9 years, 13 out of 18 cases (72 %) required further surgery by THR. Only 7 out of 18 subjects (39 %) reported an ongoing postoperative clinical benefit, and would retrospectively redo the same surgical approach again. The five patients that did not require THR were still satisfied after 9 years. CONCLUSIONS: In patients with early- stage femoral head osteonecrosis core decompression combined with the implantation of a demineralised bone matrix leads to a limited, temporary pain relief as seen in core decompression alone. However, long-term results were not encouraging with a high rate of conversion to arthroplasty. Therefore, core decompression with implantation of a demineralised bone matrix may be not appropriate to avoid THR in the long term.

[First experience and preliminary clinical results with the cervical disc replacement DISCOVER]. / Erste Erfahrungen und vorläufige klinische Ergebnisse mit der zervikalen Bandscheibenprothese DISCOVER.

AIM: The Discover (DePuy Spine, Raynham, MA, USA) is a newly developed device for cervical disc replacement that is available since 2007 in the EU. To date there are no clinical studies on the Discover. Preliminary clinical and intraoperative results from a pilot study should be compared with data for other commonly used prostheses. METHOD: In a prospective study 70 patients underwent cervical disc surgery in 2007. Clinical parameters were the neck disability index (NDI), VAS for neck and arm pain and neurological deficits. The segmental angles were determined by Cobb's method preoperatively and after 12 months. Intraoperative parameters like time of surgery and blood loss as well as complications during the postoperative course were recorded. Clinical controls after 8 weeks, 6 and 12 months were done. RESULTS: Mean age was 44.3 years. In total, 101 devices in 70 patients (27 two level, 2 three level) were implanted. Average time for surgery amounted to 68 minutes per patient and 54 minutes per prosthesis. Average blood loss was 80 mL. There were no intraoperative complications. All patients, except for 3 surgical revisions, were examined clinically and radiologically after 8 weeks, 6 and 12 months. Study parameters like NDI and VAS for arm and neck pain showed a significant (p < 0.001) improvement at all follow-ups compared to the preoperative situation. However, the value of VAS for arm pain in the follow-up rose again significantly (p < 0.05). The motor deficit improved in 33% completely and in 67% incompletely. Sensory disturbances were unchanged in 17%, improved in 73% and completely resolved in 10%. The average segmental angle improved from 3.1 degrees preoperatively to 5.3 degrees (p < 0.05) after 12 months. Up to the end of the follow-up 8.6% complications were recorded. These were 1 temporary dysphonia and 3 surgical revisions due to translations of the devices (4.3%) and 2 heterotopic ossifications (2.8%). CONCLUSION: This is the first study on the Discover. The results of clinical scores, intraoperative data and complications are encouraging and comparable to those from other commonly used types of cervical disc replacement. Regarding the duration of surgery, the correction of segmental angle and the amount of heterotopic ossifications, the Discover proved to be advantageous. However, for a definitive evaluation the follow-up period is still too short.

Bone tissue and plasma concentrations of linezolid and vancomycin in rabbits with prosthesis-related infection due to MRSA.

BACKGROUND: Due to its safety profile and ease of oral administration, linezolid became an alternative to vancomycin in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. The aim of our study was to compare bone tissue and plasma concentrations of linezolid and vancomycin in prosthesis-related MRSA infection in a rabbit model. MATERIAL AND METHODS: During implantation of titanium cylinders into the femurs of nine rabbits, a bacterial suspension of MRSA was added to induce infection. Antibiotic treatment was started eight hours later. Antibiotic concentrations in plasma (day one, three and seven) and bone (day seven) were determined by HPLC analysis. RESULTS: At steady state the mean peak and trough plasma levels of linezolid were 29.0 microg/mL and 8.2 microg/ mL and for vancomycin 39.1 microg/mL and 28.2 microg/mL. On day seven the mean peak concentration of linezolid in plasma was 28.5 microg/mL and after six hours 26.3 microg/mL and for vancomycin 53.8 microg/mL and 29.1 microg/mL after six hours. Vancomycin showed a penetration into the infected bone (femur) of 53% of plasma concentration, into the uninfected 28%, linezolid 11% (for both six hours after administration). CONCLUSION: In conclusion, we observed a higher rate of tissue penetration for vancomycin than for linezolid into femur bone in this animal model. As linezolid offers the option for oral treatment of gram-positive organisms, results of further studies comparing vancomycin and linezolid are keenly awaited.

[Gait analysis in limb-preserving tumour surgery--kinematic gait patterns after resection of malignant bone tumours near the knee joint]. / Ganganalyse bei extremitätenerhaltender Tumorchirurgie--Vergleich der Bewegungsmuster nach Resektion primär maligner Tumoren im Bereich des Kniegelenkes.

AIM: Limb-preserving surgery is the most common therapeutic approach in cases of malignant bone tumours near the knee joint. Although good functional results have been reported for tumours located in the distal femur, tumours in the proximal tibia have been investigated less frequently. The objective of the current study was to compare the kinematic gait patterns in patients with tumours in the femur vs. the tibia. METHOD: 11 patients with an arthroplasty after a primary malignant bone tumour were included (5 femur, 6 tibia). Their speed-specific kinematic gait patterns were quantified. 10 healthy volunteers and 6 patients with normal knee arthroplasty served as a reference group. RESULTS: The tibia patients walked significantly more slowly than the femur patients. They showed a similar overall gait pattern predominantly characterised by a hyperextended knee during stance. CONCLUSION: The differences in walking speed between the two groups of tumour patients did not transfer to different gait patterns. Limb-preserving surgery is thus a valuable therapeutic option also for patients with primary tumours in the tibia.

[Pathogenesis of knee osteoarthrist]. / So kommt es zur Gelenkzerstörung.

More than 20% of the population of over 60-year olds suffers from degenerative joint diseases of the lower extremities. The cause of primary osteoarthritis of the knee is still unknown. A multifactorial genesis is presumed that includes genetic, nutritional, hormonal and age-related factors. On the other hand, secondary osteoarthritis is a sequela of predisposing factors. The most frequent are axial deformities, pre-existing conditions or injuries. Pre-osteoarthritis appears as dysplasias and dystopias (abnormal presentation) of the patella and axial misalignments, incongruities and joint damage after fractures. The result is the mechanical destruction of the cartilage that, in turn, initiates a vicious circle of further cartilage loss.

[Long-term results of the anatomic stem "Euroform"]. / Langzeitergebnisse des anatomischen Titanhüftschaftes "Euroform"

PURPOSE: To date there is a lack of long-term results of anatomic hip stems in the literature. In this context we present our 10-year results with the hip stem "Euroform". METHODS: In a retrospective cohort study 90% of the 51 stems implanted in our institute in the years 1993/94 51 stems were reexamined. Of them 39 were implanted cement-free while 11 were cemented. RESULTS: After 10 to 12 years no revision surgery of the cement-free stems was necessary or performed because of stem problems, in one case of a cemented stem revision was done because of cup problems. The survival rate for the complete prostheses was 97.5% after 10 years and 92% after 12 years. The revision surgery was done for cup problems. The satisfaction rate was "1.9" (according to the German school ranking system), the Merle d'Aubigné score was "good" (>10 points). However, one problem was the high rate of PE deterioration which depended on the inclination. CONCLUSION: Both the cemented and the cement-free forms of the "Euroform" stem gives good long-term results. The longevity of the prostheses is limited by polyethylene wear.

Transplantation of mesenchymal stromal cells on mineralized collagen leads to ectopic matrix synthesis in vivo independently from prior in vitro differentiation.

BACKGROUND: Tissue engineering using mesenchymal stromal cells (MSC) represents a promising approach for bone regeneration. Nevertheless, the optimal constructs have yet to be determined. It still remains unclear if there is a benefit of in vitro differentiation of MSC prior to transplantation or if undifferentiated MSC hold the optimal potential concerning new tissue formation. METHODS: After isolation and in vitro expansion, MSC were seeded on mineralized collagen sponges and transplanted in a heterotopic SCID mice model (n=12). While group A contained undifferentiated MSC, in group B cells were cultivated for 14 days in vitro under osteogenic conditions prior to implantation. Results were compared with non-loaded scaffolds (group C). Animals were killed for investigation at 4 and at 8 weeks. RESULTS: In situ hybridization demonstrated integration of MSC for up to 8 weeks in groups A and B. Histology revealed significantly more extracellular matrix synthesis in MSC-seeded scaffolds containing calcium phosphate and collagen type I at 4 and 8 weeks after transplantation compared with unloaded controls. At a biochemical level, higher levels of specific alkaline phosphatase expression were detected in MSC-loaded scaffolds (P<0.05). Scaffolds containing undifferentiated and differentiated MSC did not appear to differ in terms of matrix synthesis and protein expression, while the number of avital cells was significant higher in those probes loaded with differentiated MSC (P<0.01). DISCUSSION: The integration of transplanted cells and MSC-associated matrix synthesis encourages the use of MSC-loaded mineralized collagen for tissue engineering of bone. Furthermore, our data suggest that in vitro differentiation of MSC does not have a positive influence in terms of improved matrix synthesis.

Incidence of rotator cuff tears in shoulder dislocations and results of therapy in older patients.

INTRODUCTION: In older patients we documented the incidence of additional injuries in shoulder dislocations in a non-randomised, prospective study and compared the results of conservative and of operative therapy of rotator cuff tears. MATERIAL AND METHODS: Between 1993 and 1999 a total of 87 patients were prospectively enrolled. In the case of documented tears of the rotator cuff in combination with symptoms persisting after conservative therapy patients were free to decide between surgical and conservative treatment. Patients were monitored for function, subjective stability, and satisfaction over a minimum follow-up period of 1 year. RESULTS: In 54% of the patients enrolled a cuff tear was documented; the frequency increased with advancing age to 100% in patients over the age of 70. Surgical treatment of the cuff tears resulted in better function and satisfaction. There were three recurrences in the conservative treatment group, while no recurrences were documented in surgically treated patients. The significant benefit of cuff repair was confirmed by regression analysis. CONCLUSION: In this selected patient group, we believe surgical repair of the symptomatic rotator cuff tear should be discussed with the patient.

[Improving the diagnosis of septic arthritis by use of a pediatric blood culture system]. / Optimierung der mikrobiologischen Diagnostik von Gelenkpunktaten mittels eines pädiatrischen Blutkultursystems.

BACKGROUND: Prognosis and outcome of bacterial joint infections are dependent on the fast and reliable identification of pathogens in the synovial fluid. Previous studies have suggested the possible advantage of using a blood culture system in contrast to conventional culture methods. PATIENTS AND METHODS: A total of 101 synovial specimens from patients presenting with symptoms suggesting septic arthritis were taken by aspiration with a sterile syringe. We compared the diagnostic results of automated analysis in a blood culture system against conventional culture on solid agar plates. RESULTS: Some 67 specimens (66.3%) were found to be negative in both preparations, while samples from 21 patients (20.8%) yielded the same microorganisms. In 13 cases (12.9%), the isolation of a pathogen was possible only with the blood culture method, whereas the conventional method never yielded a positive result when the blood culture was negative. Thus, the diagnostic yield was significantly improved by use of the blood culture system (P <0.001). CONCLUSION: The use of a commonly available blood culture system offers a fast, reliable and cost-effective approach for the diagnosis of septic arthritis and should therefore be considered as an useful alternative to conventional culture methods.

[Garden I femoral neck fractures: conservative vs operative therapy]. / Die mediale Schenkelhalsfraktur Typ I nach Garden: konservative vs. operative Therapie. Ergebnisse einer retrospektiven Studie.

INTRODUCTION: Treatment recommendations vary for Garden I fractures of the proximal femur. The aim of our retrospective study was to determine the results of functional treatment of these injuries. MATERIAL AND METHODS: A total of 54 consecutive patients were enrolled, and their data (age, comorbidities, treatment, complications, etc.) were ascertained and stored in a database. Initial treatment consisted in early mobilization and weight bearing in all patients. RESULTS: In 24 cases (44%) no complications at all were observed in the course of conservative treatment. In 28 cases (52%) surgical treatment was necessary due to early fracture dislocation. Analysis of the X-ray images showed that in 9 of these 28 cases the functional treatment had not been clearly indicated, i.e., incomplete impaction of the fragments. When these patients are excluded the success rate of conservative treatment was 53%, as two additional late complications occurred and were treated surgically (1x AVN, 1x nonunion). With reference to the survival rate, score, and patient satisfaction, there was no difference between conservative and operative treatment (p=0.478). The risk of a secondary dislocation increases with the number of risk factors (p=0.008). DISCUSSION: An attempt at functional treatment with close X-ray monitoring is appropriate in these fractures, since this makes it possible to avoid surgery in about half of the patients while achieving functional results comparable to those yielded by surgery.

[Improving microbiological diagnostics in septic orthopaedic surgery. Comparative study of patients receiving systemic antibiotic therapy]. / Mikrobiologische Diagnostik in der septisch-orthopädischen Chirurgie. Vergleichsstudie bei Patienten unter Antibiotikatherapie.

MATERIAL AND METHODS: This prospective study included 63 patients with confirmed infections of soft tissue, joints, bones or implants. During 110 surgical interventions, 124 swab and deep tissue sample pairs were taken and analysed microbiologically using standard procedures. RESULTS: In 40 patients who had not received prior antibiotic treatment, 57 sample pairs (swabs/tissue) were taken. In 70%, growth of microorganisms could be observed in both swabs and tissue samples. Growth in tissue sample only was observed in 14% and in 14% no growth could be detected. In 67 sample pairs taken from 23 patients who had received systemic antimicrobial treatment prior to surgery, microbial growth in both specimens was detected in 40%. Growth in tissue sample only was observed in 22% and 34% of the samples remained without detectable growth. The overall sensitivity of the tissue samples (70%) was significantly higher than in swab samples (44%) for the pretreated group. CONCLUSION: The use of intraoperative tissue samples for microbiological diagnostics in septic orthopaedic surgery must be considered a "gold standard". The higher sensitivity of intraoperative tissue samples is particularly important in patients receiving systemic antibiotic therapy prior to surgical interventions.

[Allogenic transplantation of human mesenchymal stem cells for tissue engineering purposes: an in vitro study]. / Allogene Transplantationsmöglichkeiten humaner mesenchymaler Stammzellen. Eine In-vitro-Studie zur Knochenregeneration.

Due to their plasticity and high proliferation capacity in vitro, human mesenchymal stem cells (MSC) are promising candidates for tissue engineering approaches of mesenchymal tissues like bone, cartilage, or tendon. Undifferentiated MSC do not express immunologically relevant cell surface markers. They inhibit the proliferation of allogeneic T-cells in vitro and elicit no immune response after allogeneic or xenogenic transplantation. Thus, MSC ought to be seen as immunoprivileged or immunomodulating cells. Here, we characterize the immune status and -behavior of MSC and MSC-derived osteogenic precursors in order to evaluate the usefulness of allogeneic MSC for tissue engineering of bone. Human MSC were isolated from bone marrow of hematologically normal voluntary donors. Osteogenic differentiation was induced by adding dexamethasone, ascorbic acid and beta-glycerophosphate. After 0, 8, 16 and 24 days, MSC were co-cultivated with allogeneic mononuclear cells. In parallel, the expression of immunologically relevant cell surface markers was monitored by flow cytometry. Undifferentiated and differentiated MSC did not stimulate allogeneic lymphocytes. MSC were negative for MHC-II, CD40, CD40L, CD80 (B7-1) and CD86 (B7-2), positive for MHC-I, and kept this expression pattern during osteogenic differentiation. Our results support the hypothesis that MSC are immunoprivileged cells which are potentially at disposal for HLA-incompatible cell replacement therapies.

[Joint empyema]. / Gelenkempyeme.

Joint infections represent a surgical emergency. For diagnosis, clinical, sonographic, and radiographic examinations are required. Furthermore, puncture of the joint with analysis of joint tap is mandatory. Therapy consists in administration of antibiotics, arthroscopic or open debridement with joint lavage, postoperative drainage and early active and passive mobilization of the joint without weight bearing. Early surgical revision is recommended in cases of insufficient recovery.

[Growth and differentiation factor 5 (GDF-5) composite improves the healing of necrosis of the femoral head in a sheep model. Analysis of an animal model]. / Das Wachstumsfaktorkomposit aus GDF-5 und mineralisiertem Kollagen verbessert die Ausheilung einer Hüftkopfnekrose. Eine Untersuchung im Tiermodell.

MATERIALS AND METHODS: After creation of necrosis in 23 sheep, the composites were implanted in half of the animals. The animals were sacrificed 6 and 12 weeks after implantation and the femora were harvested. The specimens were investigated by microradiography, computed tomography, and histologically. RESULTS: The GDF-5 composites were effective in the necrosis model. Osseous regeneration of the necrosis and the drill track were accelerated and enhanced by the composites. In treated animals the necrosis was nearly healed and the drill track was filled with bone after 12 weeks. In the control group the track was partially filled with fibrous tissue and necrotic lesions were still present. Specific side effects of the growth factor or the matrix were not documented. This was documented by histological scoring and CT investigation. DISCUSSION: The application of an absorbable GDF-5 composite in combination with a core decompression procedure may enhance the healing of devitalized bone defects and is a promising approach for further studies.

[Adult mesenchymal stem cells for the regeneration of musculoskeletal tissue]. / Adulte mesenchymale Stammzellen zur Regeneration muskuloskeletaler Gewebe.

Mesenchymal stem cells can be isolated from human bone marrow aspirates, and, thanks to their differentiation potential and good in vitro culture properties, represent an attractive cell line for the replacement of mesenchymal tissue, i. e. tissue engineering. Both in vitro and in vivo, they can differentiate into cartilage, bone, tendons and fat cells, and--in contrast to embryonic stem cells--are not underethical scrutiny. Cultured in three-dimensions on a variety of carrier substances, they have already been successfully employed for the reconstruction of mesenchymal tissues in numerous studies involving both small and large animal models. While a clinical application in humans has also been successful in pilot studies, numerous points still remain to be clarified, underscoring the need for further intensive research before wide-scale clinical application can be contemplated. Only then can it be shown whether the associated high expectations are justified.

[Mesenchymal stem cells for tissue engineering of bone: 3D-cultivation and osteogenic differentiation on mineralized collagen]. / Mesenchymale Stammzellen zum Tissue Engineering von Knochen: Dreidimensionale osteogene Differenzierung auf mineralisiertem Kollagen.

AIM: Due to their plasticity and high proliferation capacity in vitro, human mesenchymal stem cells (MSC) are promising candidates for substitution of mesenchymal tissues, such as bone. According to the tissue engineering concept, combinations of cells and three dimensional scaffolds are used to replace damaged tissue. Although various attempts have been made, the optimal combination of cells and artificial scaffold has not been found so far. METHODS: In this work, human MSC were isolated from bone marrow aspirates according to standard protocols and cultivated on mineralized collagen. Osteogenic differentiation was induced by medium containing dexamethasone, ascorbic acid and beta-glycerophosphate. Cell proliferation on the scaffold (WST-1 vitality assay, total protein measurement) and osteogenic differentiation (quantitative Real-Time-RT-PCR) were monitored for 24 days. RESULTS: Viable cells were found within the matrix throughout the cultivation period using histological and histochemical methods. Effective osteogenic differentiation could be demonstrated by the increase of expression of osteogenic marker genes (such as alkaline phosphatase) on a molecular level. CONCLUSION: Our results make the cell/matrix construct investigated in this work a promising candidate for tissue engineering of bone using mesenchymal stem cells. This has to be tested further by in vivo analysis.

[Telecommunication and telepathology in orthopedic oncology. Possibilities in diagnosis and therapy of primary malignant bone tumors]. / Telekommunikation und Telepathologie in der orthopädischen Onkologie. Möglichkeiten bei Diagnostik und Therapie primär maligner Knochentumore.

The rareness of primary malignant bone tumors and the difficulty of differential diagnosis make this field a part of oncology in which the consulting physician must rely on consistent histopathological monitoring of highest quality throughout the diagnostic and therapeutic process. In a pilot project of the Department of Bone Pathology of the University of Hamburg and the Orthopedic Department of the University of Heidelberg, 190 cases of suspected primary bone tumor were the subject of interdisciplinary discussion between July 2001 and March 2003 using a telepathology system established for this purpose. Diligent differential diagnoses were made prior to the biopsy; optimal location and further strategy for the biopsy were discussed and determined according to the guidelines of the international bone tumor centers. This also included the decision if intraoperative pathological examination of frozen sections should be performed. In 51 cases such examinations were performed. Those results immediately influenced the surgical procedure. Telepathology performed as described in this article led to a close interdisciplinary cooperation over a large distance and helped significantly to optimize therapy of patients with malignant bone tumors.

[Experiences with vascular pedicled fibula in reconstruction of osseous defects in primary malignant bone tumors]. / Erfahrungen mit der gefässgestielten Fibula in der Rekonstruktion von ossären Defekten bei primär malignen Knochentumoren.

To bridge large bone defects after resection of primary malignant bone tumors, an autologous free vascularized fibular graft was used in 31 patients (15 x upper limb, 16 x lower limb). The median bone defect measured 16 cm (7-29.5 cm). At the lower extremity the vascularized fibular transplant was reinforced with an allograft and different osteosyntheses. At the upper limb stabilization of the transplant was obtained exclusively by plate osteosynthesis or condylar plate. Applications and the authors' experiences are described and discussed in terms of clinical outcome, graft union, functional outcome, and complications for each localization. After a median of 48 months, ten complications at the upper limb and eight complications at the lower limb, respectively, were seen requiring secondary surgical revision. Major complications such as perioperative deaths or secondary amputations were not observed. Functional evaluation showed better results for the lower than for the upper extremity, due mainly to en bloc resection of proportionally large amounts of soft tissues around the shoulder girdle for local tumor control. Despite the demanding operative procedure and a large number of controllable complications, the good functional outcome and high patient satisfaction indicate that the free vascularized fibular graft is an option for limb-sparing surgery of primary malignant bone tumors.