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.

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.

[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.

Middle-term results of threaded acetabular cups. High failure rates five years after surgery.

We report our results using three different threaded acetabular components (Mecring A, Mecring B and Weill) in 715 hips with a follow-up of between one and ten years (median: 99.1, 56.5, 38.3 months, respectively). All cups were implanted with one type of cementless stem. The clinical results were good or acceptable in about 70% of the hips, but signs of loosening with radiolucency and/or migration were found in 10.1%. Radiological evidence of loosening did not correlate significantly with the clinical outcome. Pain was not a reliable indicator of loosening and its absence sometimes allowed severe osteolysis to develop. Twenty-five hips were revised (3.5%) for aseptic loosening of the acetabular component. Kaplan-Meier estimates of the cumulative rate of failure showed a rapid increase five years after the initial operation, but no significant correlation with gender, age or weight. The high rate of failure indicates that further use of these acetabular components cannot be recommended. Annual radiographs are required to assess osteolysis even if the patients are free from pain.

A new animal model of femoral head necrosis induced by intraosseous injection of ethanol.

There is no reliable animal model of the early stages of osteonecrosis of the femoral head (ONFH) for the evaluation of new therapeutic approaches. In this study, we propose a new animal model of femoral head osteonecrosis. Pure ethanol was injected into the centre of the femoral head in adult Merino sheep under fluoroscopic control. After 3, 6 and 12 weeks the animals were killed and the femoral heads were harvested. Microradiographic and histological changes were analysed and recorded. Partial necrosis was documented over a period of 12 weeks in all animals. The appearance of necrosis in combination with intact macrotexture, macrocirculation and joint cartilage is similar to the features described in early ONFH in humans. Due to its efficacy and its similarity to the early stages of ONFH in humans, this model may be suitable to evaluate new therapeutic techniques in the treatment of ONFH.

Subchondral vascularisation and osteoarthritis.

A prospective experiment was carried out in 40 rabbits in which the blood supply to the patella was interrupted for defined periods from 2 weeks to 6 months. With prolonged ischaemia, there were clear changes in the articular cartilage which were comparable with those seen in human osteoarthritis.

[Undiagnosed fractures of all metatarsals in a diabetic woman]. / Nicht diagnostizierte Frankturen sämtlicher Metatarsalia bei einer Diabetikerin.

In the case presented here we demonstrate the history of a 31-year old woman who had been known to be diabetic for more than 10 years. In the beginning she complained of an isolated fracture of the first metatarsal bone. Because of incomplete immobilisation, but without major trauma, fracture of the metatarsal I-V developed. On an outpatient basis diagnosis was delayed for 6 months because of a misinterpreted scintigraphy without performing x-ray examination. In our clinic treatment consisted of immobilisation in a cast and non-weightbearing. The update knowledge diabetic osteopathy and osteoarthropathy and the consequences for treatment are discussed.

[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.

[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.

[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.

[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.

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.

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.

[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.

[Tumor-associated hypophosphatemic osteomalacia: case report and literature review]. / Tumorassoziierte, hypophosphatämische Osteomalazie: Fallpräsentation und Literaturübersicht.

Despite the great number of neoplastic entities, which are able to cause this disease, "oncogenous osteomalacia" is hardly known as a paraneoplastic phenomenon. Without removing the not constantly malignant tumor as the underlying cause recovery is not possible. Until now pathogenesis is unknown. Together with a review of the literature a case report is presented, in which a malignant fibrous histiocytoma of soft tissue caused an untreatable osteomalacia. Because of failure of local tumor control prognosis in this case must be considered fatal.

[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.