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INTRODUCTION: Current treatment strategies for osteoporotic vertebral compression fractures (VCFs) focus on cement-associated solutions. Complications associated with cement application are leakage, embolism, adjacent fractures, and compromise in bony healing. This study comprises a validated VCF model in osteoporotic sheep in order to (1) evaluate a new cementless fracture fixation technique using titanium mesh implants (TMIs) and (2) demonstrate the healing capabilities in osteoporotic VCFs. METHODS: Twelve 5-year-old Merino sheep received ovariectomy, corticosteroid injections, and a calcium/phosphorus/vitamin D-deficient diet for osteoporosis induction. Standardized VCFs (type AO A3.1) were created, reduced, and fixed using intravertebral TMIs. Randomly additional autologous spongiosa grafting (G1) or no augmentation was performed (G2, n = 6 each). Two months postoperatively, macroscopic, micro-CT and biomechanical evaluation assessed bony consolidation. RESULTS: Fracture reduction succeeded in all cases without intraoperative complications. Bony consolidation was proven for all cases with increased amounts of callus development for G2 (58.3%). Micro-CT revealed cage integration. Neither group showed improved results with biomechanical testing. CONCLUSIONS: Fracture reduction/fixation using TMIs without cement in osteoporotic sheep lumbar VCF resulted in bony fracture healing. Intravertebral application of autologous spongiosa showed no beneficial effects. The technique is now available for clinical use; thus, it offers an opportunity to abandon cement-associated complications.

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INTRODUCTION: Vertebral compression fractures (VCFs) are one of the most common injuries in the aging population presenting with an annual incidence of 1.4 million new cases in Europe. Current treatment strategies focus on cement-associated solutions (kyphoplasty/vertebroplasty techniques). Specific cement-associated problems as leakage, embolism and the adjacent fracture disease are reported adding to open questions like general fracture healing properties of the osteoporotic spine. In order to analyze those queries animal models are of great interest; however, both technical difficulties in the induction of experimental osteoporosis in animal as well as the lack of a standardized fracture model impede current and future in vivo studies. This study introduces a standardized animal model of an osteoporotic VCF type A3.1 that may enable further in-depth analysis of the afore mentioned topics. MATERIAL AND METHODS: Twenty-four 5-year-old female Merino sheep (mean body weight: 67 kg; range 57-79) were ovariectomized (OP1) and underwent 5.5 months of weekly corticosteroid injections (dexamethasone and dexamethasone-sodium-phosphate), adding to a calcium/phosphorus/vitamin D-deficient diet. Osteoporosis induction was documented by pQCT and micro-CT BMD (bone mineral density) as well as 3D histomorphometric analysis postoperatively of the sheep distal radius and spine. Non osteoporotic sheep served as controls. Induction of a VCF of the second lumbar vertebra was performed via a mini-lumbotomy surgical approach with a standardized manual compression mode (OP2). RESULTS: PQCT analysis revealed osteoporosis of the distal radius with significantly reduced BMD values (0.19 g/cm(3), range 0.13-0.22 vs. 0.27 g/cm(3), range 0.23-0.32). Micro-CT documented significant lowering of BMD values for the second lumbar vertebrae (0.11 g/cm(3), range 0.10-0.12) in comparison to the control group (0.14 g/cm(3), range 0.12-0.17). An incomplete burst fracture type A3.1 was achieved in all cases and resulted in a significant decrease in body angle and vertebral height (KA 4.9°, range: 2-12; SI 4.5%, range: 2-12). With OP1, one minor complication (lesion of small bowel) occurred, while no complications occurred with OP2. CONCLUSIONS: A suitable spinal fracture model for creation of VCFs in osteoporotic sheep was developed. The technique may promote the development of improved surgical solutions for VCF treatment in the experimental and clinical setting.

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BACKGROUND: All diabetic neuroosteoarthropathy (Charcot arthropathy) treatment concepts are focused on a long-term infection-free, ulcer-free, and plantigrade sufficiently stable foot in order to avoid amputation. Reconstructive arthrodesis techniques for severe deformities are associated with high postoperative complication rates. This study reports a detailed complication analysis and provides a strategy that may help detect patients at risk for a complicated postoperative course. METHODS: The study comprised 43 feet in 37 patients with severe non-plantigrade or unstable Charcot deformity, Eichenholtz stages II/III (Sanders and Frykberg types II-V), who underwent reconstructive arthrodesis of the mid- and/or hindfoot. Patients were retrospectively enrolled 4.5 years postoperatively (range 1.8-11.2 years). All patients showed at least two out of five positive Pinzur high-risk criteria (immuno-compromising illnesses, large bone deformity, longstanding ulcer overlying infected bone, regional osteopenia, obesity). Follow-up included a detailed clinical analysis and radiologic assessment with emphasis on complication analysis and evaluation in accordance to the PEDIS classification system. RESULTS: Significantly lower overall complication rates, as well as re-operation, reulceration and amputation counts were found for patients with a cumulative PEDIS count below 7. For PEDIS single criteria, significantly lower overall complication rates were found for patients without signs of occlusive peripheral artery disease, an ulcer extent <0.9 cm(2), ulcer depth including erosion and inflammation of the skin and subcutaneous tissues only. Soft-tissue complications affected 49 % of patients, hardware breakage 33 %, hardware loosening 19 %, non-union 18 % and amputation 21 %. Radiographs revealed a correct reconstruction and restoration of all foot axes postoperatively with partial recollapse at the lateral foot column; however, fixation strength for the medial column was maintained. CONCLUSIONS: Internal corrective arthrodesis for patients within the deformed stages of Charcot deformity can provide adequate reconstruction, as assessed by intraoperative radiographic measures, that exhibit superior long-term stability for the medial column. Despite a high risk patient population, a favourable outcome in terms of overall complication, re-ulceration, and amputation rates for patients/feet with a cumulative PEDIS count below 7 was found. The cut-off value of 7 may aid clinical decision-making during preoperative planning for Charcot deformity.

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BACKGROUND: Despite the known demographic shift with expected doubled rate of vertebral body fractures by the year 2050, a standardized treatment concept for traumatic and osteoporotic incomplete burst fracture of the truncal spine does not exist. This study aims to determine whether minimally invasive fracture care for incomplete osteoporotic thoracolumbar burst fractures using intravertebral expandable titanium mesh cages is a suitable procedure and may provide improved safety in terms of cement-associated complications in comparison to kyphoplasty procedure. METHODS: In 2011/2012, 15 patients (10 women, 5 men; mean age 77) with 15 incomplete osteoporotic thoracolumbar burst fractures (T10 to L4) were stabilized using intravertebral expandable titanium mesh cages (OsseoFix®) as part of a prospective study. X-ray, MRI and bone density measurements (DXA) were performed preinterventionally. The clinical and radiological results were evaluated preoperatively, postoperatively and after 12 months according to the visual analogue scale (VAS), the Oswestry Disability Index (ODI), X-ray (Beck Index, Cobb angle) and CT analyses. Wilcoxon rank sum test, sign test and Fischer's exact test were used for statistical evaluation. RESULTS: A significant reduction in pain intensity (VAS) from preoperative 8.0 to 1.6 after 12 months and significant improvement in activity level (ODI) from preoperative 79.0 to 30.5 % after 12 months were revealed. Radiologically, the mean kyphotic angle according to Cobb showed significant improvements from preoperative 9.1° to 8.0° after 12 months. A vertebral body subsidence was revealed in only one case (6.7 %). No changes in the position of the posterior wall were revealed. No cement leakage or perioperative complications were seen. CONCLUSION: As a safe and effective procedure, the use of intravertebral expandable titanium mesh cages presents a valuable alternative to usual intravertebral stabilization procedures for incomplete osteoporotic burst fractures and bears the potential to reduce cement-associated complications. TRIAL REGISTRATION: German Clinical Trials Register (DKRS) DRKS00008833 .

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BACKGROUND: Charcot osteo-neuroarthropathy (CN) of the foot can induce severe instability and deformity. Results of a consecutive clinical multi-centre study with Midfoot Fusion Bolt (MFB, Synthes GmbH, Oberdorf, Switzerland) are reported. METHODS: All patients (aged 18 years and older) treated between 2009 and 2013 with surgical reconstruction of the midfoot with MFB for CN were included. Demographics, pre-surgical health status, details of foot pathology, details of surgery, postoperative treatment, treatment failure, and adverse events were registered. The following radiographic angles were measured on pre-op, post-op and last follow-up radiographs: talo-1st metatarsal (TMT) angle dorsoplantar and lateral view, and calcaneo-5th metatarsal angle. RESULTS: Forty-seven patients (48 feet) were included in three centres. In 38 patients (80.1%) diabetes was diagnosed. Wound healing problems occurred in 21% of patients and recurrent ulceration in 13%. Revision surgery for loss of correction was performed in three cases (6%). Union rate at final follow-up was 98%. Major amputation for deep infection was performed in two patients (4%), minor amputation at the foot level in three cases (6%). Failure was more frequent when only one MFB (instead of 2 or 3) was used and no Gastrocnemius lengthening was performed. Radiographic alignment significantly improved pre- versus postoperatively and preoperatively versus follow-up. CONCLUSIONS: Realignment and fixation with MFB in severe CN result in adequate correction with minimal loss of correction in the observed clinical course. The non-union rate was lower than previously reported. Stable fixation with MFB is a valuable treatment option for CN with minimal loss of correction and high union rates. The use of a minimum of two bolts is recommended to avoid recurrent deformity. Clinical Trials.gov: NCT01770639.

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This study analyses the effect of eptotermin α application into fractured vertebrae. It is hypothesized that eptotermin α is capable to enhance bony healing of the osteoporotic spine. In 10 Merino sheep osteoporosis induction was performed by ovariectomy, corticosteroid therapy and calcium/phosphorus/vitamin D-deficient diet; followed by standardized creation of lumbar vertebral compression fractures (VCFs) type A3.1 and consecutive fracture reduction/fixation using expandable mesh cages. Randomly, intravertebral eptotermin α (G1) or no augmentation was added (G2). Macroscopic, micro-CT, and biomechanical evaluation assessed bony consolidation two months postoperatively: Micro-CT data revealed bony consolidation for all cases with significant increased callus development for G2 (60%) and BV/TV (bone volume/total volume 73.45%, osteoporotic vertebrae 35.76%). Neither group showed improved biomechanical stability. Eptotermin α enhanced mineralisation in VCFs in an experimental setup with use of cementless augmentation via an expandable cage. However, higher bone mineral density did not lead to superior biomechanical properties.

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INTRODUCTION: Charcot arthropathy may lead to a loss of osteoligamentous foot architecture and consequently loss of the plantigrade alignment. In this series of patients a technique of internal corrective arthrodesis with maximum fixation strength was provided in order to lower complication rates. MATERIALS/METHODS: 21 feet with severe nonplantigrade diabetic Charcot deformity Eichenholtz stages II/III (Sanders/Frykberg II/III/IV) and reconstructive arthrodesis with medial and additional lateral column support were retrospectively enrolled. Follow-up averaged 4.0 years and included a clinical (AOFAS score/PSS), radiological, and complication analysis. RESULTS: A mean of 2.4 complications/foot occurred, of which 1.5/foot had to be solved surgically. 76% of feet suffered from soft tissue complications; 43% suffered hardware-associated complications. Feet with only 2 out of 5 high risk criteria according to Pinzur showed significantly lower complication counts. Radiographs revealed a correct restoration of all foot axes postoperatively with superior fixation strength medially. CONCLUSION: Late corrective arthrodesis with medial and lateral column stabilization in the nonplantigrade stages of neuroosteoarthropathy can provide reasonable reconstruction of the foot alignment. Nonetheless, overall complication/reoperation rates were high. With separation into low/high risk criteria a helpful guide in treatment choice is provided. This trial is registered with German Clinical Trials Register (DRKS) under number DRKS00007537.

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INTRODUCTION: There is a high incidence of vertebral burst fractures following low velocity trauma in the elderly. Treatment of unstable vertebral burst fractures using the same principles like in stable vertebral burst fractures may show less favourable results in terms of fracture reduction, maintenance of reduction and cement leakage. In order to address these shortcomings this study introduces cementless fixation of unstable vertebral burst fractures using internal fixators and expandable intravertebral titanium mesh cages in a one-stage procedure via minimum-invasive techniques. MATERIAL AND METHODS: A total of 16 consecutive patients (median age 76 years, range 58-94) with unstable thoracolumbar burst fractures and concomitant osteoporosis were treated by an internal fixator inserted via minimum invasive technique one level above and below the fractured vertebra. Fracture reduction was achieved and maintained by transpedicular placement of two titanium mesh cages into the fractured vertebral body during the same procedure. Intra- and postoperative safety of the procedure as well as analysis of reduction quality was analysed by 3D C-arm imaging or CT, respectively. Clinical and radiographic follow-up averaged 10.4 months (range 4.5-24.5). RESULTS: Stabilization of the collapsed vertebral body was achieved in all 16 cases without any intraoperative complication. Surgical time averaged 102 ± 6.6 minutes (71-194). The postoperative kyphotic angle (KA) and Cobb angle revealed significant improvements (KA 13.7° to 7.4°, p < 0.001; Cobb 9.6° to 6.0°, p < 0.002) with partial loss of reduction at final follow-up (KA 8.3°, Cobb 8.7°). VAS (Visual Analogue Scale) improved from 7.6 to 2.6 (p < 0.001). Adjacent fractures were not observed. One minor (malposition of pedicle screw) complication was encountered. CONCLUSION: Cementless fixation of osteoporotic burst fractures revealed substantial pain relief, adequate maintenance of reduction and a low complication rate. Bony healing after unstable osteoporotic burst fractures is possible. TRIAL REGISTRATION: www.germanctr.de DRKS00005657.

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INTRODUCTION: Vertebral compression fractures (VCFs) affect 20% of people over the age of 70 with increasing incidence. Kypho-/vertebroplasty as standard operative procedures are associated with limitations like cement leakage, limited reduction capabilities, and risk for adjacent fractures. To address these shortcomings, we introduce a new minimal invasive cementless VCF fixation technique. METHODS: Four patients (72.3 years, range 70-76) with VCFs type AO/Müller A1.3 and concomitant osteoporosis were treated by minimal invasive transpedicular placement of two intervertebral mesh cages for fracture reduction and maintenance. Follow-up included functional/radiological assessment and clinical scores and averaged 27.7 months (24-28). RESULTS: Endplate reduction was achieved in all cases (mean surgery time: 28.5 minutes). Kyphotic (KA) and Cobb angle revealed considerable improvements postoperatively (KA 14.5° to 10.7°/Cobb 10.1° to 8.3°). Slight loss of vertebral reduction (KA: 12.6°) and segment rekyphosis (Cobb: 10.7°) were observed for final follow-up. Pain improved from 8.8 to 2.8 (visual analogue scale). All cases showed signs of bony healing. No perioperative complications and no adjacent fractures occurred. CONCLUSION: Preliminary results in a small, selected patient collective indicate the ability of bony healing for osteoporotic VCFs. Cementless fixation using intravertebral titanium mesh cages revealed substantial pain relief, adequate reduction, and reduction maintenance without complications. Trial registration number is DRKS00005657, German Clinical Trials Register (DKRS).

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INTRODUCTION: The classification system of Rockwood and Young is a commonly used classification for acromioclavicular joint separations subdividing types I-VI. This classification hypothesizes specific lesions to anatomical structures (acromioclavicular and coracoclavicular ligaments, capsule, attached muscles) leading to the injury. In recent literature, our understanding for anatomical correlates leading to the radiological-based Rockwood classification is questioned. The goal of this experimental-based investigation was to approve the correlation between the anatomical injury pattern and the Rockwood classification. MATERIALS AND METHODS: In four human cadavers (seven shoulders), the acromioclavicular and coracoclavicular ligaments were transected stepwise. Radiological correlates were recorded (Zanca view) with 15-kg longitudinal tension applied at the wrist. The resulting acromio- and coracoclavicular distances were measured. RESULTS: Radiographs after acromioclavicular ligament transection showed joint space enlargement (8.6 ± 0.3 vs. 3.1 ± 0.5 mm, p < 0.05) and no significant change in coracoclavicular distance (10.4 ± 0.9 vs. 10.0 ± 0.8 mm). According to the Rockwood classification only type I and II lesions occurred. After additional coracoclavicular ligament cut, the acromioclavicular joint space width increased to 16.7 ± 2.7 vs. 8.6 ± 0.3 mm, p < 0.05. The mean coracoclavicular distance increased to 20.6 ± 2.1 mm resulting in type III-V lesions concerning the Rockwood classification. CONCLUSIONS: Trauma with intact coracoclavicular ligaments did not result in acromioclavicular joint lesions higher than Rockwood type I and II. The clinical consequence for reconstruction of low-grade injuries might be a solely surgical approach for the acromioclavicular ligaments or conservative treatment. High-grade injuries were always based on additional structural damage to the coracoclavicular ligaments. Rockwood type V lesions occurred while muscle attachments were intact.

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OBJECTIVE: Head-preserving fracture care especially for the elderly may be complicated by acetabular screw penetration, cut out, delayed union or femoral head necrosis. The following comparative study analyses whether a new angular stable device may overcome these shortcomings. MATERIAL AND METHODS: The Targon FN plate (BBraun/Aesculap, Germany) employs up to four angular stable telescoping screws for the fixation of the head fragment. In a prospective study patients with displaced and undisplaced intracapsular femoral neck fractures where treated by closed reduction and fracture fixation using either the Targon FN implant or a standard sliding hip screw (SHS). Patients were followed up clinically, radiographically and via telephone at a mean of follow-up time of 15.5 months. RESULTS: Fifty-two patients (mean age: 67 years) with femoral neck fractures were treated with either Targon FN (27 patients) or SHS (25 patients). Time for surgery did not differ within the two groups (56 min Targon FN vs. 55 min SHS). Eight patients with SHS (32%) and four patients (15%) with Targon FN experienced cut out of the lag screw and received hip replacement (p<0.05). Implant failure occurred after a mean of 1.8 months after SHS and 6.0 months after Targon FN implantation. Final radiographs revealed substantial subsidence in both groups (5.0mm Targon FN; 9.8mm SHS, p=0.055) with a clear trend to less subsidence for the Targon FN group. Furthermore, asymmetrical telescoping of the lag screws occurred in 30% (n=8), complete depletion of telescoping distance in 11% (n=3) in the Targon FN group. Functional assessment using the HHS assessment tool, however, presented with slightly better results for the SHS treatment (87.7 ± 13.9) when compared to Targon FN fixation (69.5 ± 14.5). CONCLUSIONS: The study revealed less subsidence of the head fragment, lower cut out rate and a lower rate of conversion to hemiarthroplasty after Targon FN fixation in comparison to a standard SHS fixation in a small number of patients with hip fractures. However, this was not accompanied by functional limitations in the SHS group.

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INTRODUCTION: To address midfoot instability of Charcot disease a promising intramedullary implant has recently been developed to allow for an arthrodesis of the bones of the medial foot column in an anatomic position. We report on a group of patients with Charcot arthropathy and instability at the midfoot where the Midfoot Fusion Bolt had been employed as an implant for the reconstruction of the collapsed medial foot column. MATERIAL AND METHODS: A total of 7 patients (median age 56.3 years, range 47-68) were enrolled with severe Charcot deformation at Eichenholtz stages I-II (Sanders and Frykberg types II and III). The medial column was stabilised primarily with an intramedullary rod (Midfoot Fusion Bolt) in stand-alone technique in order to reconstruct the osseous foot geometry. The bolt was inserted in a retrograde mode via the head of MTI and forwarded into the talus. Follow-up time averaged 27 months (range 9-30). RESULTS: Intraoperative plantigrade reconstruction and restoration of the anatomic foot axes of the medial column was achieved in all cases with the need for revision surgery in 6 out of 7 patients due to soft tissue problems (2 impaired wound healing, 1 postoperative haematoma, 3 early infection). Implant-associated problems were seen in one case intra-operatively with fracture of the first metatarsal shaft and two cases with implant loosening of the MFB and need for implant removal during long time follow-up. Two patients underwent lower leg amputation due to a progressive deep soft tissue infection. One patient healed uneventfully without need for revision surgery. Except for one case recurrent ulcerations were not observed, so far. CONCLUSION: Medial column support in midfoot instability of Charcot arthropathy with a single intramedullary rod does not provide enough stability to achieve osseous fusion. MFB loosening was associated with deep infection in a majority of our cases. To prevent early loosening of the intramedullary rod and to increase rotational stability, additional implants as angular stable plates are needed at the medial column and eventually an additional stabilisation of the lateral foot column where manifest instability exists at the time of primary surgical intervention.

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INTRODUCTION: Hook plate fixation of acromioclavicular (AC) joint separations carries the disadvantage of compulsory implant removal, occasional implant fatigue and secondary loss of reduction. This study compares the clinical and radiological outcome of a new polyaxial angular stable hook plate (HP) with absorbable polydioxansulfate (PDS) sling. MATERIALS AND METHODS: Between 2002 and 2009, out of a consecutive series of 81 patients with symptomatic Rockwood type V lesions 52 patients received clinical and radiographic follow-up (HP: n = 27; PDS: n = 25). HP patients were prospectively analyzed and retrospectively compared with the PDS group. Radiological follow-up included comparative coraco- and acromioclavicular distance (CCD/ACD) measurements as percentage of the uninjured shoulder. For clinical follow-up a standardized functional shoulder assessment with Constant Score, DASH Score, Taft Score and a self-report questionnaire including the visual analog scale (VAS) was carried out. RESULTS: Direct postoperative radiographs showed an overcorrection of CCD in the HP group (-4.4% of the uninjured side) and failure of anatomic correction in the PDS group (+11.0%). After implant removal, CCD increased in the HP group extensively to 16.7% (overall loss of reduction: 21.1%) and 23.9% in the PDS group. Redisplacement (100% increase of CCD) occurred in five cases (HP: 2, PDS: 3) and partial loss of reduction in four cases of each group. Comparing functional results no differences could be seen between both the groups (Constant-Score HP: 91.2 points, PDS: 94.6 points; Taft-Score HP: 9.4 points, PDS: 10.0 points). The DASH-Score revealed better results for PDS group (3.4 points, HP: 8.0 points). Signs of acromial osteolysis appeared in five cases (18.5%) in HP group. There was no case of implant failure. The X-rays of six patients (HP: 4, PDS: 2) showed AC-joint-osteoarthritis. CONCLUSION: Hook plate fixation employing a polyaxial angular stable plate finally restores the coracoclavicular distance more accurately than augmentation with a PDS sling. Although in HP group no implant failure occurred, major disadvantages are initial overcorrection and acromial osteolysis. Both have no influence on final functional results.

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