Burst fractures lead to a fracture-associated intervertebral vacuum phenomenon: a case series of 305 traumatic fractures of the thoracolumbar spine.

PURPOSE: Intervertebral vacuum phenomenon (IVP) is mainly seen as a sign of degenerative disc diseases. Although studies have shown that IVP also occurs after traumatic injuries to the spine, its clinical relevance in spinal fractures remains unknown. Therefore, the aim of this study was to analyse the prevalence, demographic parameters and fracture morphology in patients with fracture-associated IVP (FAVP) of the thoracolumbar spine. METHODS: In this retrospective cohort study, patients with traumatic fractures of the thoracolumbar spine who were admitted between January 2014 and December 2015 were included. CT scans were assessed for the presence of intervertebral areas of gaseous radiolucency, which were defined as IVP. Fractures were classified according to the AOSpine Thoracolumbar Spine Injury Classification System. Demographic and anamnestic data, including age, sex and trauma mechanism, were documented. RESULTS: A total of 201 patients with 305 fractures were included. Seventy-three patients with 98 fractures had follow-up CTs. Sixty-eight patients had IVP, of whom 46 patients had FAVP. On the follow-up CT, a significant correlation was found between A3 fractures and FAVP, while initial FAVP was significantly correlated with age and low-velocity trauma mechanisms. Initial degenerative IVP also showed a significant correlation with age. CONCLUSIONS: FAVP occurred significantly more often in burst fractures and therefore may lead to disc degeneration due to nutritional supply disturbances via the vertebral endplate. As surgical management strategies for burst fractures are intensively discussed, the appearance of FAVP should be taken in consideration.

Positive Outcome After a Small-Caliber Gunshot Fracture of the Upper Cervical Spine without Neurovascular Damage.

BACKGROUND: Gunshot wounds to the cervical spine most frequently concur with serious injuries to the spinal cord and cervical vessels and often have a fatal outcome. CASE REPORT: We describe the case of a 35-year-old male with a complex fracture of the C2 vertebra body and a mandibular fracture after a penetration gunshot to the cervical spine. Computed tomography (CT) at admission revealed the exact extent of the fractures and the small caliber bullet lodged next to the C2 vertebra. In this rare and extremely lucky case no collateral vascular or neurological damage was detected. Eighteen months after surgical bullet removal and posterior C1-C3 fusion complete bone healing of the C2 vertebra was achieved and there were no secondary neurovascular deficits. CONCLUSIONS: Immediate surgical C1-C3 fixation resulted in an excellent outcome without secondary neurovascular deficits in this rare case of traumatic complex C2 vertebral fracture caused by a gunshot injury.

Influence of wound drainage in primary total knee arthroplasty without tourniquet.

PURPOSE: Although it remains the golden standard, several authors have questioned the role of pneumatic tourniquets in primary knee arthroplasty in recent studies. An intra-articular wound drainage is widely used in the field of total knee arthroplasty although the benefit of postoperative wound drainage is controversial in the literature. This study questioned whether the use of an intra-articular drain is an advance over the lack of a drain in total knee arthroplasty which is performed without a tourniquet. METHODS: We documented the ROM, the knee circumference at the upper patellar pole pre-operatively and on days two, four and six postoperatively. The blood volume and loss was calculated. As surrogate parameter for wound healing we counted the number of days until no residual secretion was observed via the wound/drainage site. RESULTS: The results of our investigation showed a significantly better wound healing without the use of a drain. All other parameters revealed no significant differences. CONCLUSION: The data of this study demonstrate a faster wound healing without the use of a postoperative wound drain in primary total knee arthroplasty which is performed without a tourniquet. Other parameters could not show any significant differences thus indicating that a postoperative wound drain has no significant advantage and the risk of a retrograde bacterial colonisation is well documented. Based on these data we recommend performing a primary total knee arthroplasty without a postoperative drain if the procedure is done without a tourniquet.

Adequate surgical treatment of periprosthetic femoral fractures following hip arthroplasty does not correlate with functional outcome and quality of life.

PURPOSE: This study aimed to analyse functional outcome and quality of life (QoL) after surgical treatment of periprosthetic femoral fractures (PPF) following total hip arthroplasty (THA). METHODS: This retrospective study assessed 67 patients from 2005 to 2012. Epidemiologic data, surgical details, comorbidities, deaths and postoperative complications were recorded. Functional assessment included Harris Hip Score (HHS) and range of motion (ROM); QoL was assessed using the Short-Form Health Survey of 36 questions (SF-36) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores. RESULTS: Mean HHS was 69 ± 21 and ROM 96° ± 17°. Mean SF-36 and WOMAC scores revealed 44 ± 7.2 and 18.9 ± 19.6, respectively. The complication rate was 25.4%; 23.7% of patients died. Analysis revealed no statistical influence on final outcome as a function of fracture type or treatment strategy. Comorbidities seem to influence functional outcome. CONCLUSION: PPF following THA are accompanied by a perceptible decline of function and remarkably high complication rates. In contrast to fracture classification and treatment type, American Society of Anesthesiologists (ASA) score predicts outcome.

Long-term functional outcome and quality of life after successful surgical treatment of tibial nonunions.

PURPOSE: Our aim was to evaluate quality of life (QoL) and functional outcome of patients with tibial nonunions after completion of surgical treatment with an average follow-up of five years. METHODS: The following data of 64 patients were retrospectively evaluated: fracture type, type and duration of surgical therapy, range of motion of the knee and ankle and American Orthopaedic Foot and Ankle Society (AOFAS) score. QoL was evaluated with the Short-Form Health Survey (SF-36) questionnaire; pain intensity, patient satisfaction and impairments of daily, professional and sport activities with a ten point visual analogue scale. RESULTS: QoL, even in cases with successfully completed treatment, was significantly reduced compared with the normal general population. Pain intensity and limited ankle dorsal extension, despite the absence of intra-articular fractures, were significantly correlated with inferior QoL. CONCLUSIONS: This study emphasises the long-term negative impact of tibial nonunions on patient QoL, even after successful surgical treatment.

A pilot study investigating the histology and growth factor content of human non-union tissue.

PURPOSE: The reason for the formation of an atrophic non-union is not clear and an altered vascularization as well as a deregulation of endogenous growth factors is hypothesized. To obtain more information, we analysed human non-union tissue regarding the histology and quantity of several growth factors. METHODS: Tissue from patients with an atrophic non-union (n = 44) or with a healed fracture (n = 13) was analysed. Using histological and immunohistochemical methods the tissue composition was investigated. On the protein level the amount of several growth factors important for bone healing was analysed. RESULTS: The tissue composition was very inhomogeneous containing fibrous, cartilaginous and bony tissue. Vessels were present in all investigated samples without a difference between the tissue from non-union and control patients. The growth factor BMP-2 was below the detection limit in all samples, whereas IL-6 and IGF-I were measured only in a few samples of both groups. TGF-ß1, VEGF-A and BMP-4 were detectable in the majority of the samples of both groups with a high variability in the amount but no difference between the groups. The quantity of both growth factors, BMP-7 and PDGF-AB, was significantly lower in the non-union tissue compared to the healed controls. CONCLUSION: The reduced quantity of BMP-7 and PDGF-AB might be responsible for the impaired healing. Further studies analysing material from more patients and investigating the early healing phases, however, are necessary to obtain further information and consequently improve healing strategies.

Surgical and Oncologic Outcome following Sacrectomy for Primary Malignant Bone Tumors and Locally Recurrent Rectal Cancer.

INTRODUCTION: Bone sarcoma or direct pelvic carcinoma invasion of the sacrum represent indications for partial or total sacrectomy. The aim was to describe the oncosurgical management and complication profile and to analyze our own outcome results following sacrectomy. METHODS: In a retrospective analysis, 27 patients (n = 8/10/9 sarcoma/chordoma/locally recurrent rectal cancer (LRRC)) were included. There was total sacrectomy in 9 (incl. combined L5 en bloc spondylectomy in 2), partial in 10 and hemisacrectomy in 8 patients. In 12 patients, resection was navigation-assisted. For reconstruction, an omentoplasty, VRAM-flap or spinopelvic fixation was performed in 20, 10 and 13 patients, respectively. RESULTS: With a median follow-up (FU) of 15 months, the FU rate was 93%. R0-resection was seen in 81.5% (no significant difference using navigation), and 81.5% of patients suffered from one or more minor-to-moderate complications (especially wound-healing disorders/infection). The median overall survival was 70 months. Local recurrence occurred in 20%, while 44% developed metastases and five patients died of disease. CONCLUSIONS: Resection of sacral tumors is challenging and associated with a high complication profile. Interdisciplinary cooperation with visceral/vascular and plastic surgery is essential. In chordoma patients, systemic tumor control is favorable compared to LRRC and sarcomas. Navigation offers gain in intraoperative orientation, even if there currently seems to be no oncological benefit. Complete surgical resection offers long-term survival to patients undergoing sacrectomy for a variety of complex diseases.

Necrotizing fasciitis: is the bacterial spectrum changing?

PURPOSE: Necrotizing fasciitis (NF) is a rare, but potentially fatal pathology. The aim of the present study was to identify the population characteristics of the NF patients, the responsible bacteria, and the differences between survivors and nonsurvivors. METHODS: In this retrospective case-control study, all patients with NF from January 1, 2005, to December 31, 2010, treated in an academic level 1 trauma center, were identified, and their medical records were reviewed. RESULTS: The mortality rate of the 24 identified patients was 20.8 %. The majority of the infections (54.2 %) (13/24) were monomicrobial. Hemolytic Streptococcus of group A (25 %) and methicillin-resistant Staphylococcus aureus (20.8 %) were the commonest germs. The mean number of comorbidities was 3.62 (standard deviation (SD) 3.58). Diabetes mellitus, cardiovascular disease, and immunosuppression were the commonest. Mean number of operations was 8.1 (SD 4.7). Five patients (20.8 %) developed a disseminated intravascular coagulation (DIC); all of them died. Nonsurvivors, who presented with deteriorated coagulation factors, developed a DIC (p < 0.001) and received more often antibiotic monotherapy (ampicillin/sulbactam) as initial empirical therapy (p < 0.001). CONCLUSIONS: The present study suggests a shift of the bacterial spectrum towards monomicrobial infections with multiresistant bacteria. The early recognition of high-risk patients and the aggressive surgical treatment with at least double-schema antibiotic therapy are of outmost importance.

Osteoid osteoma: treatment outcome and long-term follow-up after MRI-guided laser ablation.

Background: Aim of this study was to investigate short-term and long-term treatment outcome, complication rates, and patient satisfaction after MRI-guided laser ablation (LA) of osteoid osteoma (OO). Methods: Thirty-five patients with OO in typical and atypical localizations were treated by MRI-guided LA with MRI thermometry in an open 1.0 T system. Twenty-nine patients underwent a standardized telephone interview including questions about recurrence, residual pain or functional symptoms, and satisfaction for short-term follow-up after a mean of 31 months. Twenty-one of these patients were available for long-term telephone follow-up after a mean of 116 months. Results: Technical success of MRI-guided LA was 100% without major complications. Two minor complications included transient local inflammation and transient damage of the peroneal nerve associated with improper patient positioning during the procedure. Primary clinical success was 92% (11/12) in typically located OO and 82% (14/17) in atypically located OO. Secondary clinical success after repeat ablation was 100% regardless of OO location. Patient satisfaction and acceptance of the intervention were very good at both short-term (97%) and long-term (100%) follow-up. Conclusions: MRI-guided LA of OO is a safe and effective treatment option resulting in high short-term and long-term patient satisfaction and acceptance rates. Recurrence and adverse events were more common in patients with atypically located OO. Level of Evidence: Level 3, non-randomized follow-up study.

Atypically Located Osteoid Osteoma: Characteristics and Therapeutic Success After Image-Guided Thermal Ablation. / Das atypisch lokalisierte Osteoidosteom: Charakteristiken und Therapieerfolg nach bildgesteuerter Thermoablation.

PURPOSE: While ostoeid osteomas (OO) are typically located in long tubular bones, OO occurring elsewhere are referred to as "atypical". Aim of our study was to review the characteristics of atypically located OO, course of symptoms and therapy, as well as clinical outcome, safety, and patient satisfaction of radiofrequency ablation (RFA). MATERIALS AND METHODS: In the period from 04/01 to 07/13, 33 patients were treated using thermal ablation (RFA or laser), partly with low temperature and short duration technique. Clinical records were analyzed. Additionally, 23 patients were interviewed via telephone. Primary endpoints were technical success, clinical success (recurrence rates), and adverse events. Secondary endpoints were course of symptoms and therapy as well as patient satisfaction. RESULTS: Mean follow-up was 22.1 ±â€Š21.5 months. Average patient age was 31.7 ±â€Š16.3 years. Localization: Most atypical OO (61 %) were located in the lower extremity, followed by axial skeleton (26 %) and upper extremity (13 %). Pain anamnesis: 74 % of patients stated that their pain occured predominantly at night and responded to NSAID, as typical for OO. Diagnostics: Patients consulted on average 4 different doctors and in 52 % patients, ≥ 3 different radiologic imaging techniques where used before the diagnosis "OO" was made. OUTCOME: Technical success of thermal ablation was 100 %. Primary clinical success was 91 %. Patient satisfaction was 100 %. No major complications occurred. CONCLUSION: In » of cases, atypical OO did not show the typical pain characteristics of OO. Image-guided thermal ablation is a promising and safe therapy also for patients with atypical OO. KEY POINTS: · Atypical OO are challenging regarding diagnostics and therapy. · Image-guided thermal ablation is a safe and effective procedure also for patients with atypical OO. · Image-guided thermal ablation shows high patient satisfaction. CITATION FORMAT: · Seemann RJ, Märdian S, Schwabe P et al. Atypically Located Osteoid Osteoma: Characteristics and Therapeutic Success After Image-Guided Thermal Ablation. Fortschr Röntgenstr 2020; 192: 335 - 342.

Local application of zoledronic acid incorporated in a poly(D,L-lactide)-coated implant accelerates fracture healing in rats.

BACKGROUND AND PURPOSE: Zoledronic acid (ZOL) has been shown in vitro and in vivo to inhibit osteoclastic activity and to regulate osteoblasts. Its antiresorptive effect is used clinically in the treatment of bone-consuming pathologies to prevent skeletal complications. Because of its effect on bone cells, there might be a possible benefit in treatment of fractures by local application from a biodegradable poly(D,L-lactide) (PDLLA) coating of osteosynthetic implants. We analyzed the effect of locally applied ZOL from a PDLLA coating of intramedullary implants on fracture healing. MATERIAL AND METHODS: Standardized midshaft fractures of the right tibia of 5-month-old rats were stabilized either with uncoated, PDLLA-coated, or ZOL-coated implants. Animals were killed 42 or 84 days after fracture. Tibiae were dissected and mechanically tested. Results Radiographs taken 42 days after fracture showed at least unilateral bridging in all groups. Maximum load and torsional stiffness were highest in the group treated with ZOL. 84 days after fracture, the torsional stiffness of the ZOL-treated group remained higher than that of the uncoated group whereas the maximum load for the control groups reached the results for the ZOL-coated group. INTERPRETATION: Local application of ZOL from PDLLA coating appears to accelerate the achievement of mechanical stability in fractures.

Mechanobiologically optimized 3D titanium-mesh scaffolds enhance bone regeneration in critical segmental defects in sheep.

Three-dimensional (3D) titanium-mesh scaffolds offer many advantages over autologous bone grafting for the regeneration of challenging large segmental bone defects. Our study supports the hypothesis that endogenous bone defect regeneration can be promoted by mechanobiologically optimized Ti-mesh scaffolds. Using finite element techniques, two mechanically distinct Ti-mesh scaffolds were designed in a honeycomb-like configuration to minimize stress shielding while ensuring resistance against mechanical failure. Scaffold stiffness was altered through small changes in the strut diameter only. Honeycombs were aligned to form three differently oriented channels (axial, perpendicular, and tilted) to guide the bone regeneration process. The soft scaffold (0.84 GPa stiffness) and a 3.5-fold stiffer scaffold (2.88 GPa) were tested in a critical size bone defect model in vivo in sheep. To verify that local scaffold stiffness could enhance healing, defects were stabilized with either a common locking compression plate that allowed dynamic loading of the 4-cm defect or a rigid custom-made plate that mechanically shielded the defect. Lower stress shielding led to earlier defect bridging, increased endochondral bone formation, and advanced bony regeneration of the critical size defect. This study demonstrates that mechanobiological optimization of 3D additive manufactured Ti-mesh scaffolds can enhance bone regeneration in a translational large animal study.

Bisphosphonates incorporated in a poly(D,L-lactide) implant coating inhibit osteoclast like cells in vitro.

Nitrogen containing bisphosphonates such as zoledronic acid (ZOL) are clinically used to prevent osteoclast induced bone loss. Previous studies indicated that bisphosphonates prevent osteoclast formation, decreases their resorption activity and lead to osteoclast apoptosis. Aim of the study was to investigate the effect of ZOL on fusion and resorption activity of osteoclast like cells (OLC) derived from human peripheral blood mononuclear cells (PBMNC) in vitro. For application of ZOL a local drug delivery system based on a coating for medical devices was used. ZOL was incorporated in the coating based on Poly(D,L-Lactide) (PDLLA) in different concentrations (10-50 microM). Control groups were treated without ZOL or ZOL pure substance in corresponding concentrations. Human PBMNCs were isolated and stimulated to form OLCs. After an experimental period of 144 h, TRAP staining of polynucleated cells was performed and TRAP positive cells were counted. A pit formation assay was performed and resorption lacunas on dentin chips were counted. Results showed a significant dose dependent decrease in the number of TRAP positive cells after exposure to ZOL incorporated in the drug delivery system or applied as pure substance. The amount of resorption lacunas was also dose dependent decreased using both application methods. In conclusion, exposure to specific concentrations of ZOL incorporated in a drug delivery system showed a significant decrease in OLC formation and activity comparable to the effect of pure substance. The effect on osteoclasts might be of clinical benefit to reduce orthopedic implant loosening and to support fracture healing.

High-dose recombinant human bone morphogenetic protein-2 impacts histological and biomechanical properties of a cervical spine fusion segment: results from a sheep model.

The 'off-label' use of high-dose recombinant human bone morphogenetic protein-2 (rhBMP-2) in lumbar and cervical fusion leads to heterotopic bone formation and vertebral osteolysis. These radiographically assessed side-effects in patients were frequently associated with an over-dosage of BMP-2. However, little is so far known about the histological, functional or biomechanical tissue consequences of over-dosage of rhBMP-2 in these specific clinical situations. We hypothesized that a high dose of rhBMP-2 in cervical spinal fusion could induce substantial alterations in bone, leading to mechanical impairment. An anterior cervical spinal fusion (C3-C4 ACDF) model in 16 sheep (aged > 2.5 years; n = 8/group) was used to quantify the consequences of a high rhBMP-2 dose (6 mg rhBMP-2) on fusion tissue compared to the 'gold standard' of autologous, cancellous bone graft. The fusion site was assessed by radiography after 0, 8 and 12 weeks. Biomechanical non-destructive testing and (immuno)histological and histomorphometrical analyses were performed 12 weeks postoperatively. Although high-dose rhBMP-2 treatment led to an advanced radiological fusion result compared to autograft treatment, heterotopic bone formation and vertebral bone resorption were induced simultaneously. Histological evaluation unveiled highly active bone-forming processes ventral to the fusion segment after 12 weeks, while radiolucent areas showed still a partial loss of regular trabecular structure, with rare signs of remodelling and restoration. Despite qualitative alteration of the trabecular bone structure within the fusion site, the massive anterior heterotopic bone formation led to a substantial increase in mechanical stiffness compared to the autograft group. Copyright © 2015 John Wiley & Sons, Ltd.

* Demineralized Bone Matrix as a Carrier for Bone Morphogenetic Protein-2: Burst Release Combined with Long-Term Binding and Osteoinductive Activity Evaluated In Vitro and In Vivo.

To allow bone defect regeneration, autologous bone grafting still represents the gold standard. However, autograft harvesting has limitations, including an additional surgery, donor site morbidity, and limited availability. Demineralized bone matrix (DBM) would represent an alternative, yet lacks sufficient osteoinductive properties. Combining DBM with a potent agent, such as bone morphogenetic protein-2 (BMP-2) might be a feasible alternative approach, optimizing an established grafting material with strong osteoinductive properties. A unique mixing device has been developed that enables perioperative handling to reach a homogeneous and standardized paste for bone defect filling. DBM proved in vitro to be a suitable carrier for BMP-2, with a documented release over 56 days at concentrations sufficient to stimulate osteogenic differentiation. At the end of the elution experiment, 56 days, bioactive BMP was still captured within the DBM. Using a sheep drill hole defect model, DBM perioperatively mixed with BMP-2 showed strong osteoinductive properties comparable to those of autologous bone and outnumbering the one of DBM alone or empty defects. Bone defect healing was enabled at diaphyseal and metaphyseal defects and thus BMP-2-doped DBM represented an easy perioperative enriching method and an efficient carrier for BMP-2. With the comparability to the clinical gold standard autologous bone, DBM mixed with BMP-2 might serve as possible alternative grafting material enabling a controlled osteogenic stimulation.

Quality and Dose Optimized CT Trauma Protocol - Recommendation from a University Level-I Trauma Center.

Purpose As a supra-regional level-I trauma center, we evaluated computed tomography (CT) acquisitions of polytraumatized patients for quality and dose optimization purposes. Adapted statistical iterative reconstruction [(AS)IR] levels, tube voltage reduction as well as a split-bolus contrast agent (CA) protocol were applied. Materials and Methods 61 patients were split into 3 different groups that differed with respect to tube voltage (120 - 140 kVp) and level of applied ASIR reconstruction (ASIR 20 - 50 %). The CT protocol included a native acquisition of the head followed by a single contrast-enhanced acquisition of the whole body (64-MSCT). CA (350 mg/ml iodine) was administered as a split bolus injection of 100 ml (2 ml/s), 20 ml NaCl (1 ml/s), 60 ml (4 ml/s), 40 ml NaCl (4 ml/s) with a scan delay of 85 s to detect injuries of both the arterial system and parenchymal organs in a single acquisition. Both the quantitative (SNR/CNR) and qualitative (5-point Likert scale) image quality was evaluated in parenchymal organs that are often injured in trauma patients. Radiation exposure was assessed. Results The use of IR combined with a reduction of tube voltage resulted in good qualitative and quantitative image quality and a significant reduction in radiation exposure of more than 40 % (DLP 1087 vs. 647 mGyxcm). Image quality could be improved due to a dedicated protocol that included different levels of IR adapted to different slice thicknesses, kernels and the examined area for the evaluation of head, lung, body and bone injury patterns. In synopsis of our results, we recommend the implementation of a polytrauma protocol with a tube voltage of 120 kVp and the following IR levels: cCT 5mm: ASIR 20; cCT 0.625 mm: ASIR 40; lung 2.5 mm: ASIR 30, body 5 mm: ASIR 40; body 1.25 mm: ASIR 50; body 0.625 mm: ASIR 0. Conclusion A dedicated adaptation of the CT trauma protocol (level of reduction of tube voltage and of IR) according to the examined body region (head, lung, body, bone) combined with a split bolus CA injection protocol allows for a high-quality CT examination and a relevant reduction of radiation exposure in the examination of polytraumatized patients Key Points · Dedicated adaption of the CT trauma protocol allows for an optimized examination.. · Different levels of iterative reconstruction, tube voltage and the CA injection protocol are crucial.. · A reduction of radiation exposure of more than 40 % with good image quality is possible.. Citation Format · Kahn J, Kaul D, Böning G et al. Quality and Dose Optimized CT Trauma Protocol - Recommendation from a University Level-I Trauma Center. Fortschr Röntgenstr 2017; 189: 844 - 854.

Collective review: bioactive implants coated with poly(D,L-lactide) and growth factors IGF-I, TGF-beta1, or BMP-2 for stimulation of fracture healing.

Demographic data reveal that due to the increasing aging of the population, complications with the musculoskeletal system will increase in the next years. One major problem in orthopedic and trauma surgery are the delayed healing or non-unions of long bone fractures. The exogenous application of growth factors can stimulate the bone healing to reduce these complications. Beside the choice of the optimal growth factor the application system is important. Therefore, we developed a new bioactive coating method for implants, which is based on a biodegradable poly(D,L-lactide) (coating thickness: 10 mum). This coating allows the incorporation of growth factors and the controlled release of these factors during the healing process without the need for further devices. The effect of different growth factors (IGF-I, TGF-beta1, and BMP-2) locally released from coated intramedullary implants on fracture healing was investigated with biomechanical and histological analysis in rats. All investigated growth factors stimulated the fracture healing as assessed with biomechanical tests and histological analysis. The local application of combined IGF-I and TGF-beta1 had the most stimulating effect on fracture healing, followed by the effect of BMP-2, IGF-I, and TGF-beta1 alone. Bioactive coating of biomechanical well-established implants can on the one hand stabilize the fracture and on the other hand stimulate healing processes to increase healing and to reduce the rate of complications.

BMPs in bone regeneration: Less is more effective, a paradigm-shift.

Worldwide, the clinical application of BMP2 (bone morphogenetic protein 2) has helped an increasing number of patients achieve bone regeneration in a clinical area lacking simple solutions for difficult bone healing situations. In this review, the historical aspects and current critical clinical issues are summarized and positioned against new research findings on efficacy and function of BMP2. Knowledge concerning how the dose of this growth factor as well as its interaction with mechanical loading influences the efficacy of bone regeneration, might open possible future strategies in cases where bony bridging is unachievable so far. In conclusion, it is apparent that there is a substantial need for continued basic research to unravel the details of its function and the underlying signaling pathways involved, to make BMP2 even more relevant and safe in daily clinical use, even though this growth factor has been known for more than 125 years.

Current concepts review: Fractures of the patella.

Fractures of the patella account for about 1% of all skeletal injuries and can lead to profound impairment due to its crucial function in the extensor mechanism of the knee. Diagnosis is based on the injury mechanism, physical examination and radiological findings. While the clinical diagnosis is often distinct, there are numerous treatment options available. The type of treatment as well as the optimum timing of surgical intervention depends on the underlying fracture type, the associated soft tissue damage, patient factors (i.e. age, bone quality, activity level and compliance) and the stability of the extensor mechanism. Regardless of the treatment method an early rehabilitation is recommended in order to avoid contractures of the knee joint capsule and cartilage degeneration. For non-displaced and dislocated non-comminuted transverse patellar fractures (2-part) modified anterior tension band wiring is the treatment of choice and can be combined - due to its biomechanical superiority - with cannulated screw fixation. In severe comminuted fractures, open reduction and fixation with small fragment screws or new angular stable plates for anatomic restoration of the retropatellar surface and extension mechanism results in best outcome. Additional circular cerclage wiring using either typical metal cerclage wires or resorbable PDS/non-resorbable FiberWires increases fixation stability and decreases risk for re-dislocation. Distal avulsion fractures should be fixed with small fragment screws and should be protected by a transtibial McLaughlin cerclage. Partial or complete patellectomy should be regarded only as a very rare salvage operation due to its severe functional impairment.

Short term in vivo biocompatibility testing of biodegradable poly(D,L-lactide)--growth factor coating for orthopaedic implants.

Fracture healing can be stimulated by exogenous application of growth factors. Using porcine and rat models the efficacy of locally delivered IGF-I and TGF-beta1 from an implant coating has been demonstrated. A thin and biomechanical stable biodegradable poly(D,L-lactide) was used to coat implants and serve as a drug carrier. Due to reports of possible foreign body reactions caused by polymer materials in orthopedic surgery, this study investigated the biocompatibility of the polylactide implant coating and the locally released growth factors during the time course of rat tibial fracture healing (days 5, 10, 15, and 28 after fracture). Monocytes/macrophages and osteoclast were detected using an monoclonal antibody against ED1 (comparable to CD68 in mice and human). The antibody ED1 stains monocytes, macrophages and osteoclast in the bone marrow and in the newly formed fracture callus. A moderate density of the monocytes/macrophages was seen in the proximal part of the medullary canal, but almost no cells were detectable in the region distal to the fracture. The amount of stained cells increased during the observation time with a maximum at days 10 and 15 followed by a decrease at day 28. No differences were detectable between the investigated groups from day 5 to 15 post fracture indicating, that the used poly(D,L-lactide) or the incorporated growth factors do not evoke an elevated immunological response compared to the uncoated titanium implant at the investigated time points. A significantly higher amount of ED1 positive cells was measured 28 days after fracture in the control group compared to the groups with the coated implants. In conclusion, no indication of a foreign body reaction due to the use of the polylactide or the growth factors was found indicating a good short-term biocompatibility of this bioactive coating.