It's the little things: On the complexity of planar electrode heating in MRI.

Neurological disorders are increasingly analysed and treated with implantable electrodes, and patients with such electrodes are studied with MRI despite the risk of radio-frequency (RF) induced heating during the MRI exam. Recent clinical research suggests that electrodes with smaller diameters of the electrical interface between implant and tissue are beneficial; however, the influence of this electrode contact diameter on RF-induced heating has not been investigated. In this work, electrode contact diameters between 0.3 and 4 mm of implantable electrodes appropriate for stimulation and electrocorticography were evaluated in a 1.5 T MRI system. In situ temperature measurements adapted from the ASTM standard test method were performed and complemented by simulations of the specific absorption rate (SAR) to assess local SAR values, temperature increase and the distribution of dissipated power. Measurements showed temperature changes between 0.8 K and 53 K for different electrode contact diameters, which is well above the legal limit of 1 K. Systematic errors in the temperature measurements are to be expected, as the temperature sensors may disturb the heating pattern near small electrodes. Compared to large electrodes, simulations suggest that small electrodes are subject to less dissipated power, but more localized power density. Thus, smaller electrodes might be classified as safe in current certification procedures but may be more likely to burn adjacent tissue. To assess these local heating phenomena, smaller temperature sensors or new non-invasive temperature sensing methods are needed.

Clinical and radiological outcome at mean follow-up of 11 years after hip arthroscopy.

INTRODUCTION: The use of hip arthroscopy (HA) has substantially increased over the last decade. However, while the benefits of HA after 1 year in patients with femoroacetabular impingement (FAI) are well documented, long-term data on the progression of osteoarthritis (OA) or patient-reported outcomes (PROMs) are lacking. OBJECTIVES: To evaluate long-term clinical and radiological outcomes after HA. MATERIALS AND METHODS: Preoperative clinical records, operative notes, and radiographs from all patients who underwent HA at our hospital between 1998 and 2006 were reviewed. Exclusion criteria were previous hip surgery or diagnostic HA. Primary endpoints were subsequent total hip arthroplasty (THA) or other hip surgery. Secondary endpoints were OA progression and PROMs. RESULTS: HA was performed in 92 consecutive patients from 1998 to 2006. Indications for HA were FAI, labral lesions, early OA, and focal osteochondral defects. Mean follow-up was 11.2 years (SD 2.5, range 7.9-16). Data from 43 patients were available for analysis; 38 patients were excluded, and 11 were lost to follow-up. 20 patients had subsequent hip surgery, of which 11 patients required THA. 33 patients (77%) stated that they would undergo HA again under the same circumstances. Longitudinal radiological analysis showed no significant OA progression in patients without THA. The Forgotten Joint Score-12 was the only PROM to significantly differ between patients who had no further surgery and patients who had undergone revision (p = 0.037). CONCLUSION: There was no significant OA progression on plain radiography at an average of 11 years post-HA. Sound indication criteria is essential, as 45% of patients required subsequent surgery.

[Concomitant fractures of the capitulum humeri and the caput radii]. / Konkomitante Fraktur des Capitulum humeri und des Caput radii.

This case report describes the osteosynthetic treatment and postoperative course of a fracture of the capitulum humeri and a concomitant fracture of the head of the radius with a follow-up over 3 months. Simultaneous fractures of the capitulum humeri and the head of the radius are rare injuries of the elbow. Due to the complex anatomical relationships this type of fracture poses a big challenge for treating traumatologists.

Evaluation of ninety-six periprosthetic hip joint infections seen within five consecutive years.

Periprosthetic hip joint infections (PHJI) are severe complications. In 2003 Zimmerli published a well-noted treatment algorithm for PHJI. The aim of this study is to evaluate outcome, analyze the applied treatment regimen and compare it to the proposed algorithm. We evaluated the outcome of 96 PHJI treated at our institution between 2008 and 2012 and analysed adherence to the algorithm and outcome in coherence with the algorithm. The operations performed were irrigation and debridement with exchange of mobile parts (45%), two-stage exchange (36%), one-stage exchange (12%) and permanent explantation (7%). 47% were acute infections, 53% were chronic. Staphylococcus aureus was the most common pathogen. The overall success rate was 88%. In 12% of the cases the chosen operation didn't follow the algorithm. Of these only 10% was successfully treated with the primary operation. We find that the algorithm proposed by Zimmerli is a useful tool and easy to translate into clinical practice. When followed it yields a high success rate.

Endovascular embolisation is a successful and safe treatment for post-operative arterial complications after total hip arthroplasty and revision surgery.

PURPOSE: Arterial complications are rare but clinically critical during or following total hip arthroplasty (THA) surgery. They usually require secondary interventions, either through open or endovascular approaches. In a retrospective study, we analysed indications for, as well as success and safety of, endovascular embolisation for arterial complications after THA. METHODS: We reviewed all arterial complications that had occurred through THA surgery and been treated by endovascular embolisation. We analysed angiographic findings, endovascular treatment, location in relation to the surgical approach and success of the interventions. RESULTS: Between 1997 and 2013 we performed 3,891 THAs at our hospital. We identified 14 patients with acute arterial complications treated by minimally invasive endovascular embolisation. Clinical findings included swelling of the ipsilateral leg, pain, prolonged wound bleeding, decreased haemoglobin and/or haemodynamic instability. Angiography revealed pseudoaneurysm in 11 patients, arteriovenous fistulas in two and extravasation of contrast media in one. Two patients showed no signs of acute bleeding. Twelve patients were treated, each with a single session of endovascular embolisation; in two additional patients, the haematoma was evacuated. No complications from the endovascular treatment were observed in this series. CONCLUSION: Endovascular embolisation is a safe and successful minimally-invasive method to treat arterial injuries occurring through THA. Therefore, it should be considered as a first-line option of treatment for those injuries.

Osteolytic changes around biodegradable cement restrictors in hip surgery.

Background and purpose - Biodegradable cement restrictors are widely used in hip arthroplasty. Like others, we observed osteolytic reactions associated with a specific cement restrictor (SynPlug; made of PolyActive) and reviewed our patients. Patients and methods - We identified 703 patients with suitable radiographs from our database (2007 to 2012) who underwent cemented hip arthroplasty and received a SynPlug biodegradable cement restrictor. We reviewed all available radiographs to determine the incidence, severity, and progression of osteolysis. Mean postoperative follow-up was 1.8 (1-7) years Results - 1 year after implantation, the femoral cortex showed thinning by 12% in the anterior-posterior view and by 8% in the axial view. This had increased to 14% and 12%, respectively, at the latest available follow-up postoperatively (at a mean of 4 years). Cortical thinning of less than 10% was found in 37% of patients, but cortical thinning of 10-30% was found in 56% of patients. In the remaining 7%, a reduction of more than 30% of the original cortical thickness was observed. Interpretation - Osteolytic changes associated with the SynPlug biodegradable bone restrictors are inconsistent and highly variable. While some patients showed increased weakening of the femoral cortex with the potential risk of periprosthetic fracture, in others the degree of osteolysis only increased slightly or stabilized after 2 or more years. Any cortical bone loss after total hip replacement should be avoided, so the use of PolyActive biodegradable cement restrictors should be discontinued. Patients with a PolyActive cement restrictor in place should be followed up closely after surgery.

Deltoid Tuberosity Index: A Simple Radiographic Tool to Assess Local Bone Quality in Proximal Humerus Fractures.

BACKGROUND: Osteoporosis may complicate surgical fixation and healing of proximal humerus fractures and should be assessed preoperatively. Peripheral quantitative CT (pQCT) and the Tingart measurement are helpful methods, but both have limitations in clinical use because of limited availability (pQCT) or fracture lines crossing the area of interest (Tingart measurement). The aim of our study was to introduce and validate a simple cortical index to assess the quality of bone in proximal humerus fractures using AP radiographs. QUESTIONS/PURPOSES: We asked: (1) How do the deltoid tuberosity index and Tingart measurement correlate with each other, with patient age, and local bone mineral density (BMD) of the humeral head, measured by pQCT? (2) Which threshold values for the deltoid tuberosity index and Tingart measurement optimally discriminate poor local bone quality of the proximal humerus? (3) Are the deltoid tuberosity index and Tingart measurement clinically applicable and reproducible in patients with proximal humerus fractures? METHODS: The deltoid tuberosity index was measured immediately above the upper end of the deltoid tuberosity. At this position, where the outer cortical borders become parallel, the deltoid tuberosity index equals the ratio between the outer cortical and inner endosteal diameter. In the first part of our study, we retrospectively measured the deltoid tuberosity index on 31 patients (16 women, 15 men; mean age, 65 years; range, 22-83 years) who were scheduled for elective surgery other than fracture repair. Inclusion criteria were available native pQCT scans, AP shoulder radiographs taken in internal rotation, and no previous shoulder surgery. The deltoid tuberosity index and the Tingart measurement were measured on the preoperative internal rotation AP radiograph. The second part of our study was performed by reviewing 40 radiographs of patients with proximal humerus fractures (31 women, nine men; median age, 65 years; range, 22-88 years). Interrater (two surgeons) and intrarater (two readings) reliabilities, applicability, and diagnostic accuracy were assessed. RESULTS: The correlations between radiograph measurements and local BMD (pQCT) were strong for the deltoid tuberosity index (r = 0.80; 95% CI, 0.63-0.90; p < 0.001) and moderate for the Tingart measurement (r = 0.67; 95% CI, 0.42-0.83; p < 0.001). There was moderate correlation between patient age and the deltoid tuberosity index (r = 0.65; p < 0.001), patient age and the Tingart measurement (r = 0.69; p < 0.001), and patient age and pQCT (r = 0.73; p < 0.001). The correlation between the deltoid tuberosity index and the Tingart measurement was strong (r = 0.84; p < 0.001). We determined the cutoff value for the deltoid tuberosity index to be 1.44, with the area under the curve = 0.87 (95% CI, 0.74-0.99). This provided a sensitivity of 0.88 and specificity of 0.80. For the Tingart measurement, we determined the cutoff value to be 5.3 mm, with the area under the curve = 0.83 (95% CI, 0.67-0.98), which resulted in a sensitivity of 0.81 and specificity of 0.85. The intraobserver reliability was high and not different between the Tingart measurement (intraclass correlation coefficients [ICC] = 0.75 and 0.88) and deltoid tuberosity index (ICC = 0.88 and 0.82). However, interobserver reliability was higher for the deltoid tuberosity index (ICC = 0.96; 95% CI, 0.93-0.98) than for the Tingart measurement (ICC = 0.85; 95% CI, 0.69-0.93).The clinical applicability on AP radiographs of fractures was better for the deltoid tuberosity index (p = 0.025) because it was measureable on more of the radiographs (77/80; 96%) than the Tingart measurement (69/80; 86%). CONCLUSIONS: The deltoid tuberosity index correlated strongly with local BMD measured on pQCT and our study evidence shows that it is a reliable, simple, and applicable tool to assess local bone quality in the proximal humerus. We found that deltoid tuberosity index values consistently lower than 1.4 indicated low local BMD of the proximal humerus. Furthermore, the use of the deltoid tuberosity index has important advantages over the Tingart measurement regarding clinical applicability in patients with proximal humerus fractures, when fracture lines obscure the Tingart measurement landmarks. However, further studies are needed to assess the effect of the deltoid tuberosity index measurement and osteoporosis on treatment and outcome in patients with proximal humerus fractures. LEVEL OF EVIDENCE: Level IV, diagnostic study.

The extended medial elbow approach-a cadaveric study.

BACKGROUND: The two most commonly used approaches to expose medial elbow structures are the flexor carpi ulnaris split and the Hotchkiss over-the-top approach. The aim of this study was to define the extended medial approach to the elbow, featuring advantages of over-the-top (proximal exposure) and additional complete exposure of the coronoid and proximal medial ulna, while respecting the internervous plane between the flexor pronator mass and flexor carpi ulnaris muscle. METHODS: In this comparative anatomic study, 12 fresh frozen cadaveric elbows were dissected alternately to study the distal limitation and exposed area of the extended medial elbow approach compared with splitting the flexor carpi ulnaris. RESULTS: Proximal ulna exposure area was comparable between the extended medial elbow approach (average, 840 mm(2)) and the flexor carpi ulnaris split (average, 810 mm(2); P = .44). The extended medial approach was limited distally by the posterior recurrent ulnar artery (mean 68 mm from medial epicondyle), whereas the first motor branch for the flexor carpi ulnaris muscle limited the second approach in 75% of the specimens (mean 29 mm from medial epicondyle, P < .001). CONCLUSIONS: The extended medial elbow approach is a single approach allowing full exposure of the medial elbow and combining the advantages of the over-the-top approach with a safe distal extension to the medial ulna. In contrast to the flexor carpi ulnaris split, our approach respects the internervous plane.

Pre-operative embolisation of spinal metastasis: technique, complication rate and outcome-clinical experience.

PURPOSE: Pre-operative embolisation of metastatic spinal tumours has the potential to decrease intra-operative blood loss. Intra-operative blood loss is multifactorial and one factor may be the embolisation technique used. The purpose of this study was to retrospectively analyse the effect of three different pre-operative embolisation techniques on intra-operative blood loss, complication rate and tumour aetiology in patients treated with a corpectomy and dorsoventral stabilisation at our institution. METHODS: We conducted a retrospective analysis of embolisation procedures for vertebral metastases performed from January 2002 to December 2011. Only pre-operatively embolised patients treated by a single-level hemicorpectomy or corpectomy procedure from T4-L5, including posterior spinal stabilisation using pedicle screws, were included. All patient charts and examinations were analysed regarding the embolisation technique, gender, age, primary tumour, time between the embolisation and surgery, intra-operative blood loss, intra-operative transfusions and complications related to embolisation. RESULTS: We identified a total of 46 patients, 25 male and 21 female patients. The mean age at the time of surgery was 66 years (range 39-84 years). The tumours treated were: 15 (33%) renal cell carcinomas, six (13%) breast carcinomas, five (11%) lung carcinomas, five (11%) urothelial carcinomas, four (9%) myelomas and 11 (24%) miscellaneous types including rectal carcinoma, thymoma and melanoma. Embolisation with coils was performed in 23 patients, particles were used in six and a combination of coils and particles in 18. The mean time between the embolisation and surgery was 23 hours (range 80-4,430 minutes). The median overall intra-operative estimated blood loss (EBL) was 2,300 ml (range 500-15,000 ml). In patients embolised with coils and particles, EBL was 2,200 ml compared to 1,450 ml in patients embolised with particles and 2,500 ml in the coil group. No statistically significant differences between the three groups could be detected. There were no complications related to the embolisation techniques. CONCLUSIONS: Pre-operative embolisation of spinal metastases using coils, particles or a combination of both is a safe and reproducible procedure. In our cohort we reported no complications during the three different embolisation techniques. No statistically significant difference regarding blood loss between the three embolisation techniques could be detected. Our data confirm existing studies concerning the control of intra-operative blood loss using different embolisation techniques. The benefit of embolisation with a combination of coils and particles compared to embolisation with particles only is questionable.

Short- or long-stem prosthesis for intramedullary bypass of proximal humeral fractures with severe metaphyseal bone loss: evaluation of primary stability in a biomechanical model.

BACKGROUND: Proximal humeral fractures with substantial metaphyseal comminution are challenging to treat. In the elderly with osteoporotic bone, arthroplasty sometimes remains the only valuable option; however, the minimally required length of stem fixation is not known. The aim of this study was to investigate the primary stability of cemented short- and long-stem prostheses with different intramedullary fracture bypass lengths. MATERIALS AND METHODS: Osteoporotic composite bone models of the humerus (Synbone, Malans, Switzerland) with 3 different fracture levels (group A, 6 cm distal to surgical neck; group B, 7 cm distal to surgical neck; and group C, 8 cm distal to surgical neck) were prepared with a cemented standard short (S)- or long (L)-stem prosthesis and were tested for torque to failure. As a reference, we used models with intact bone (group R-O) and a short-stem prosthesis implanted at the surgical neck (group R-P). The radiographic bypass index (BI) was calculated before testing (fracture level to stem tip [in millimeters]/outer cortical diameter at fracture level [in millimeters]). RESULTS: The resulting BIs of each group were as follows: 1.7 in group A-S, 3.4 in group A-L, 1.4 in group B-S, 3.2 in group B-L, 1.0 in group C-S, and 2.9 in group C-L. Compared with group R-O, the torques to failure of groups B-S and C-S were significantly lower, whereas only group C-S was significantly weaker than group R-P (P < .01). Comparing short- and long-stem bypasses of different fracture heights, we found that only group C-L showed a significantly higher resistance to torque (P < .01). CONCLUSIONS: A short-stem bypass with a BI of 1.7 was sufficient for primary stability tested by torque to failure in this biomechanical setting. For smaller BIs, a long-stem prosthesis should be considered. LEVEL OF EVIDENCE: Basic science study, biomechanics.

Minimally invasive and open surgical treatment of proximal tibia fractures using a polyaxial locking plate system: a prospective multi-centre study.

PURPOSE: The purpose of this study was to determine whether a polyaxial locking plate of the latest generation (NCB PT(®), Zimmer Inc.) which can be applied both open and minimally invasively, can be used as a routine method of treatment for proximal tibia fractures. METHODS: Eighty-six patients (35 women, 51 men; mean age 51 years) were enrolled in this prospective multicentre trial. Ninety-six percent of the fractures were intra-articular (AO type B and C); 36 % were treated open and 64 % minimally invasively. Follow-up was obtained three, six and 12 months after surgery. RESULTS: No implant failure occurred. At 12 months, the functional result using a knee-specific score was good to excellent in 95 %, and 99 % of the fractures were radiologically healed. CONCLUSION: The system is a versatile implant for proximal tibia fracture treatment. Polyaxiality and a specific locking mechanism are compatible with different fracture patterns. The minimally invasive technique effectively protects soft tissues but should not be performed at the expense of fracture reduction. Early functional results and complication rate are comparable to those in the literature.

Second generation locked plating of proximal humerus fractures--a prospective multicentre observational study.

Surgical treatment of most displaced proximal humerus fractures is challenging due to osteoporosis. Locking plates are intended to provide superior mechanical stability. In a prospective multicentre study 131 patients were treated with second generation locked plating (NCB-PH, Zimmer, Inc.). The open procedure (n = 78) was performed using a deltopectoral approach; the minimally invasive technique (n = 53) involved percutaneous reduction and an anterolateral deltoid split approach. Clinical and radiological follow-up was obtained. Improvement in function (ROM) was statistically significant. Fracture type (AO) had the most significant impact on the incidence of complications. The most frequent complications detected were intra-articular screw perforation (15%) and secondary displacement (8%). Complication rate and functional outcome of the NCB-PH are comparable to reports in the literature. Not all problems are likely to be solved by this new generation of implants, i.e. secondary dislocation still occurred in 8% of our patients.

The treatment of periprosthetic fractures with locking plates: effect of drill and screw type on cement mantles: a biomechanical analysis.

INTRODUCTION: Periprosthetic fractures after cemented hip replacement are a challenging problem to manage. Biomechanical studies have suggested the benefit of using locking screws for plate fixation, but there are concerns whether screws damage the cement mantle and promote crack propagation leading to construct failure. METHOD: In this biomechanical study, different screw types were implanted into the cement mantle after pre-drilling holes of different sizes, in unicortical and bicortical configuration. The presence of cracks and the pull-out resistance of these screws were then evaluated. RESULTS: No unicortical screw induced cracks. Screws with a shortened tip, smaller flutes and double threads were significantly better for pull-out resistance. Bicortical screws were associated with a risk of local cement mantle damage, but also with a significantly greater holding power. By increasing the drill diameter, the onset of cracks decreased, but so does the pull-out resistance.

Fabrication and validation of reference structures for the localization of subdural standard- and micro-electrodes in MRI.

OBJECTIVE: Report simple reference structure fabrication and validate the precise localization of subdural micro- and standard electrodes in magnetic resonance imaging (MRI) in phantom experiments. APPROACH: Electrode contacts with diameters of 0.3 mm and 4 mm are localized in 1.5 T MRI using reference structures made of silicone and iron oxide nanoparticle doping. The precision of the localization procedure was assessed for several standard MRI sequences and implant orientations in phantom experiments and compared to common clinical localization procedures. MAIN RESULTS: A localization precision of 0.41 ± 0.20 mm could be achieved for both electrode diameters compared to 1.46 ± 0.69 mm that was achieved for 4 mm standard electrode contacts localized using a common clinical standard method. The new reference structures are intrinsically bio-compatible, and they can be detected with currently available feature detection software so that a clinical implementation of this technology should be feasible. SIGNIFICANCE: Neuropathologies are increasingly diagnosed and treated with subdural electrodes, where the exact localization of the electrode contacts with respect to the patient's cortical anatomy is a prerequisite for the procedure. Post-implantation electrode localization using MRI may be advantageous compared to the common alternative of CT-MRI image co-registration, as it avoids systematic localization errors associated with the co-registration itself, as well as brain shift and implant movement. Additionally, MRI provides superior soft tissue contrast for the identification of brain lesions without exposing the patient to ionizing radiation. Recent studies show that smaller electrodes and high-density electrode grids are ideal for clinical and research purposes, but the localization of these devices in MRI has not been demonstrated.

Early results in the treatment of proximal humeral fractures with a polyaxial locking plate.

OBJECTIVES: We report early results using a second generation locking plate, non-contact bridging plate (NCB PH((R)), Zimmer Inc. Warsaw, IN, USA), for the treatment of proximal humeral fractures. The NCB PH combines conventional plating technique with polyaxial screw placement and angular stability. DESIGN: Prospective case series. SETTING: A single level-1 trauma center. PATIENTS: A total of 50 patients with proximal humeral fractures were treated from May 2004 to December 2005. INTERVENTION: Surgery was performed in open technique in all cases. MAIN OUTCOME MEASURES: Implant-related complications, clinical parameters (duration of surgery, range of motion, Constant-Murley Score, subjective patient satisfaction, complications) and radiographic evaluation [union, implant loosening, implant-related complications and avascular necrosis (AVN) of the humeral head] at 6, 12 and 24 weeks. RESULTS: All fractures available to follow-up (48 of 50) went to union within the follow-up period of 6 months. One patient was lost to follow-up, one patient died of a cause unrelated to the trauma, four patients developed AVN with cutout, one patient had implant loosening, three patients experienced cutout and one patient had an axillary nerve lesion (onset unknown). The average age- and gender-related Constant Score (n = 35) was 76. CONCLUSIONS: The NCB PH combines conventional plating technique with polyaxial screw placement and angular stability. Although the complication rate was 19%, with a reoperation rate of 12%, the early results show that the NCB PH is a safe implant for the treatment of proximal humeral fractures.

Integrity Assessment of a Hybrid DBS Probe that Enables Neurotransmitter Detection Simultaneously to Electrical Stimulation and Recording.

Deep brain stimulation (DBS) is a successful medical therapy for many treatment resistant neuropsychiatric disorders such as movement disorders; e.g., Parkinson's disease, Tremor, and dystonia. Moreover, DBS is becoming more and more appealing for a rapidly growing number of patients with other neuropsychiatric diseases such as depression and obsessive compulsive disorder. In spite of the promising outcomes, the current clinical hardware used in DBS does not match the technological standards of other medical applications and as a result could possibly lead to side effects such as high energy consumption and others. By implementing more advanced DBS devices, in fact, many of these limitations could be overcome. For example, a higher channels count and smaller electrode sites could allow more focal and tailored stimulation. In addition, new materials, like carbon for example, could be incorporated into the probes to enable adaptive stimulation protocols by biosensing neurotransmitters in the brain. Updating the current clinical DBS technology adequately requires combining the most recent technological advances in the field of neural engineering. Here, a novel hybrid multimodal DBS probe with glassy carbon microelectrodes on a polyimide thin-film device assembled on a silicon rubber tubing is introduced. The glassy carbon interface enables neurotransmitter detection using fast scan cyclic voltammetry and electrophysiological recordings while simultaneously performing electrical stimulation. Additionally, the presented DBS technology shows no imaging artefacts in magnetic resonance imaging. Thus, we present a promising new tool that might lead to a better fundamental understanding of the underlying mechanism of DBS while simultaneously paving our way towards better treatments.

The influence of local bone quality on fracture pattern in proximal humerus fractures.

INTRODUCTION: Bone mineral density and fracture morphology are widely discussed and relevant factors when considering the different treatment options for proximal humerus fractures. It was the aim of this study to investigate the influence of local bone quality on fracture patterns of the Neer classification as well as on fracture impaction angle in these injuries. MATERIALS AND METHODS: All acute, isolated and non-pathological proximal humerus fractures admitted to our emergency department were included. The fractures were classified according to Neer and the humeral head impaction angle was measured. Local bone quality was assessed using the Deltoid Tuberosity Index (DTI). The distribution between DTI and fracture pattern was analysed. RESULTS: 191 proximal humerus fractures were included (61 men, mean age 59 years; 130 women, mean age 69.5). 77 fractures (40%) were classified as one-part, 72 (38%) were two-part, 24 (13%) were three- and four-part and 18 (9%) were fracture dislocations. 30 fractures (16%) were varus impacted, whereas 45 fractures (24%) were classified as valgus impacted. The mean DTI was 1.48. Valgus impaction significantly correlated with good bone quality (DTI ≥ 1.4; p = 0.047) whereas no such statistical significance was found for the Neer fracture types. DISCUSSION: We found that valgus impaction significantly depended on good bone quality. However, neither varus impaction nor any of the Neer fracture types correlated with bone quality. We conclude that the better bone quality of valgus impacted fractures may be a reason for their historically benign amenability to ORIF. On the other hand, good local bone quality does not prevent fracture comminution.

Should patients with brain implants undergo MRI?

Patients suffering from neuronal degenerative diseases are increasingly being equipped with neural implants to treat symptoms or restore functions and increase their quality of life. Magnetic resonance imaging (MRI) would be the modality of choice for the diagnosis and compulsory postoperative monitoring of such patients. However, interactions between the magnetic resonance (MR) environment and implants pose severe health risks to the patient. Nevertheless, neural implant recipients regularly undergo MRI examinations, and adverse events are rarely reported. However, this should not imply that the procedures are safe. More than 300 000 cochlear implant recipients are excluded from MRI, unless the indication outweighs the excruciating pain. For 75 000 deep brain stimulation (DBS) recipients quite the opposite holds true: MRI is considered an essential part of the implantation procedure and some medical centres deliberately exceed safety regulations, which they refer to as crucially impractical. Permanent MRI-related neurological dysfunctions in DBS recipients have occurred in the past when manufacturer recommendations were exceeded. Within the last few decades, extensive effort has been invested to identify, characterise and quantify the occurring interactions. Yet today we are still far from a satisfying solution concerning a safe and beneficial MR procedure for all implant recipients. To contribute, we intend to raise awareness of the growing concern, summon the community to stop absurdities and instead improve the situation for the increasing number of patients. Therefore, we review implant safety in the MRI literature from an engineering point of view, with a focus on cochlear and DBS implants as success stories of neural implants in clinical practice. We briefly explain fundamental phenomena which can lead to patient harm, and point out breakthroughs and errors made. Then, we end with conclusions and strategies to avoid future implants from being contraindicated in MR examinations. We believe that implant recipients should enter MRI, but before doing so, it should be made sure that the procedure is reasonable.

Biceps Femoris Injury a Rarity: A Case Report.

Isolated biceps femoris rupture is a rare injury associated with limitation in the function of the knee. We present a 65-year-old man who sustained an isolated complete rupture of the tendon of the biceps femoris. The diagnostic was reached after clinical examination and magnetic resonance imaging of the affected knee. This case was treated with a surgical tendon reconstruction. The outcome was good and the patient was able to walk normally again without limitation, even if he did not comply with our recommendation.