[Cost analysis of inpatient versus outpatient intravenous antibiotic treatment for periprosthetic joint infections : A simulation]. / Kostenanalyse stationärer und ambulanter intravenöser Antibiotikatherapie periprothetischer Gelenkinfektionen : Eine Simulation.

BACKGROUND: Parenteral antibiotic administration in the treatment of periprosthetic joint infections (PJI) often requires inpatient settings. This is associated with significant costs to the healthcare system. OBJECTIVE: The costs of inpatient parenteral antibiotic treatment (IPAT) and simulated costs of outpatient parenteral antibiotic treatment (OPAT) were compared in patients with PJI. Evaluations were carried out from the perspectives of cost bearers (insurances) and healthcare providers (hospitals). MATERIAL AND METHODS: The analysis and simulations were performed for all cases with the ICD-10 diagnosis T84 in the treatment year 2015. RESULTS: The simulated reduction of 159 bed-days in the 12 patients included in the study resulted in a reduction of the total costs of>18,000 € from the perspective of the health insurance. From the perspective of the hospitals the pure proceeds were improved by >22,000 €. The total costs of OPAT were >57,000 € for the health insurance. For hospitals the difference of policlinic proceeds and costs of OPAT showed a loss of >1500 €. CONCLUSION: For hospitals the OPAT is overall financially advantageous. Further advantages due to opportunity costs seem to be interesting. For cost bearers OPAT is associated with an additional financial expenditure, particularly due to costs of outpatient medication. The private sector should be considered due to the assumed additional burden as well as the assumed patient comfort.

Publication rate of abstracts presented at the Congress of the European Federation of National Associations of Orthopaedics and Traumatology (EFORT).

BACKGROUND: The publication rate of presented abstracts is an important parameter to assess the scientific quality of medical congresses. It has been investigated for many congresses in orthopaedics and traumatology, but until now, it has not been studied for the congress of the European Federation of National Associations of Orthopaedics and Traumatology (EFORT). The aims of this study were to determine: (1) the publication rate of the EFORT congress, (2) factors that favour publication of abstracts presented at the EFORT congress, (3) the consistency between the congress abstract and publication in relation to authorship. HYPOTHESIS: There are factors that favour publication of abstracts presented at the EFORT congress and there is a high consistency between the congress abstract and publication in relation to authorship. MATERIALS AND METHODS: All 1624 abstracts presented at the EFORT congress in 2011 were included in this study, to allow a 5-year period for publication after the congress. The characteristics of the abstracts presented were studied and the publication rate in peer-reviewed journals was determined using a Medline search. RESULTS: The publication rate for studies presented at the 2011 EFORT congress was 42% (677/1624 abstracts), with a mean of 16 months (-56 to 60 months) between congress and publication. The mean impact factor of the publications was 1.8 (0-7.6). A significantly higher publication rate was found for: oral presentations (52%; 322/617) versus posters (35%; 355/1007) (p<0.01), experimental studies (53%; 110/208) versus clinical studies (40%; 507/1254) (p<0.01), and studies with higher levels of evidence of I or II (59%; 144/244) versus studies with lower levels of evidence of III or IV (36%; 362/1005) (p<0.01). A new author was added in 59% (403/677) of the publications. DISCUSSION: Factors that favour publication of abstracts presented at the EFORT congress are oral presentation, experimental study, and a study with a higher level of evidence of I or II. It is common that a new author is added in the publication. Nevertheless, a high percentage of congress abstracts (58%; 947/1624) remains unpublished. LEVEL OF EVIDENCE: IV, retrospective study.

Cost-analysis of inpatient and outpatient parenteral antimicrobial therapy in orthopaedics: A systematic literature review.

BACKGROUND: Increasing numbers of total joint arthroplasties and consecutive revision surgery are associated with the risk of periprosthetic joint infections (PPJI). Treatment of PPJI is complex and associated with immense socio-economic burden. One treatment aspect is parenteral antiinfective therapy, which usually requires an inpatient setting [Inpatient parenteral antibiotic therapy (IPAT)]. An alternative is outpatient parenteral treatment [Outpatient parenteral antibiotic therapy (OPAT)]. To conduct a health economic cost-benefit analysis of OPAT, a detailed cost analysis of IPAT and OPAT is required. So far, there is a lack of knowledge on the health economic effects of IPAT and OPAT for PPJI. AIM: To review an economic comparison of IPAT and OPAT. METHODS: A systematic literature review was performed through Medline following the PRISMA guidelines. RESULTS: Of 619 identified studies, 174 included information of interest and 21 studies were included for quantitative analysis of OPAT and IPAT costs. Except for one study, all showed relevant cost savings for OPAT compared to IPAT. Costs for IPAT were between 1.10 to 17.34 times higher than those for OPAT. CONCLUSION: There are only few reports on OPAT for PPJI. Detailed analyses to support economic or clinical guidelines are therefore limited. There is good clinical evidence supporting economic benefits of OPAT, but more high quality studies are needed for PPJI.

[A minimally invasive technique for removal of a firmly fixed Küntscher nail in primary hip arthroplasty]. / Eine minimalinvasive Technik zur Entfernung eines fest verklemmten Küntscher-Nagels in der primären Hüftendoprothetik.

This article reports the case of an 80-year-old male patient who presented to this hospital with symptomatic arthritis of the left hip. The special feature of this case was a Küntscher nail in the left femur that had been in situ for more than 50 years. Before implantation of the total hip arthroplasty the nail first had to be removed. As the Küntscher nail is a rarity nowadays there is no standardized procedure for the removal of such a nail. This case report describes a minimally invasive possibility to remove a Küntscher nail in total hip arthroplasty.

Risk factors for secondary displacement in conservatively treated isolated greater tuberosity fractures: An analysis of 82 cases.

INTRODUCTION: The optimal treatment of isolated fractures of the greater tuberosity is an important topic of current surgical research. While non-displaced fractures are amenable to conservative treatment, displacement of the fragment can result in rotator cuff malfunction and impingement. For the present study, risk factors predicting secondary fragment displacement were analyzed. HYPOTHESIS: Certain risk factors determine a higher risk of secondary displacement in patients with greater tuberosity fractures. PATIENTS AND METHODS: All patients diagnosed with a fracture of the greater tuberosity and initially treated non-surgically at our Level I trauma center between January 2008 and July 2015 were included in this retrospective analysis. Patients were grouped into: no secondary displacement (group 1) and secondary displacement at follow-up (group 2). The following risk factors were analyzed: age, gender, side of fracture, initial displacement, fragment/head ratio, fragment shape, dislocation, concomitant fractures and concomitant fractures to the same extremity. RESULTS: 82 patients (42 male, 40 female) were eligible for further analyses. Median follow-up was 8.0±39.5 days. Patients with secondary displacement (group 2) were significantly older (group 1: 51.7±15.5, group 2: 68.3±14.3; p<0.001) and had significantly more shoulder dislocations (p=0.024), whereas gender (p=0.299), side of fracture (p=0.189) and fragment/head ratio (p=0.660) showed no significant different distribution between both groups. Finally, split-type fractures increased the risk of secondary displacement. DISCUSSION: The present study identified age older than 65 years to be an important risk factor for secondary displacement in the conservative management of fractures of the greater tuberosity. Furthermore, fracture type and shoulder dislocations are factors associated with an increased relative risk for secondary displacement. LEVEL OF PROOF: III, Retrospective comparative study.

Dual-position calibration markers for total hip arthroplasty: theoretical comparison to fixed calibration and single marker method.

PURPOSE: Digital templating is considered a standard for total hip arthroplasty. Different means for the necessary calibration of radiographs are known. While single marker calibration with radiopaque spheres is the most common, it is associated with possible significant deviations from the true magnification of the hip. Notably, fixed magnification factors showed better results. Therefore, a dual-position calibration marker method was simulated and compared to the established methods. METHODS: First, an empirical fixed magnification factor was identified and applied to a series of radiographs. Second, three magnification factors were generated based on sagittal patient data of 398 CT scans. These methods were compared to the fixed factor. RESULTS: The fixed factor was 122.6%. In the clinical application, the error of the fixed factor was 2.5% while the error of the single marker was 5.2%. In the CT cohort, the mean reference factor was 120.5% in females and 120.3% in males. The reference factor was compared to sex-specific means, sex-specific linear functions, and sex-specific cubic functions. The best results were found for the linear regression model with a mean difference of 0.8% from the reference value. No proportional bias was found (p = 0.623). CONCLUSION: The simulation of the dual-position marker method using the linear regression model showed promising results, superior to all other methods. In future studies, its clinical application should be tested.

Influence of calibration on digital templating of hip arthroplasty.

INTRODUCTION: Digital templating for total joint replacement is the current standard. For image calibration, external calibration markers (ECM) are used. However, there are concerns regarding the precision of the method. This study aimed to identify the direct influence of calibration errors on digital templating. PATIENTS AND METHODS: A retrospective analysis of 100 post-operative radiographs with unilateral total hip arthroplasty was performed. The magnification factor of the ECM and of the internal prosthetic femoral head (ICM) as a reference value was calculated for each radiograph. Two blinded observers performed templating of the contralateral hip using a randomized list for all radiographs and both markers. The component size templated by the ECM magnification was compared to the reference by the ICM magnification. RESULTS: Mean magnification factors of ICM and ECM differed significantly (p = 0.006). The absolute difference was 5.2% (range 0.0-23.3%, SD 4.8%). Templating of the acetabular or the femoral component showed no significant differences (p = 0.120, p = 0.599). Differences of more than one size were found in 26% of the acetabular components and 14% of the femoral components and differences over two sizes in 10% respectively 3%. Correlation coefficients for magnification error and size differences of acetabular components were - 0.645 (p < 0.001) and for the femoral component - 0.607 (p < 0.001). INTERPRETATION: The calibration error of external calibration markers in digital templating for hip replacement influences component sizes significantly. Thus, correct positioning of ECM is of utmost importance.

Operative treatment of geriatric ankle fractures with conventional or locking plates. A retrospective case-control study.

BACKGROUND: The incidence of geriatric ankle fractures continues to rise due to demographic changes. While locking plates have become standard implants for injuries of other body regions, clinical studies on their use for geriatric ankle fractures are rare. METHODS: Therefore, a retrospective case-control study, including 333 patients with a mean age of 73.5 years was performed. 263 patients underwent operative fixation with one- third tubular plates and 70 were treated with locking plates. Early outcomes and complication rates of locking plates as compared with conventional one- third tubular plates are described. RESULTS: In the present study, patients treated with locking plates were older and suffered from more severe fracture patterns. In addition, these patients had more severe comorbidities. Treatment with conventional or locking plate fixation resulted in a comparable complication and revision rate. A matched pair analysis showed significantly more complications and required revision surgeries and a trend towards more implant failures in the group that underwent conventional plating. CONCLUSIONS: Therefore, we conclude that precontoured locking plates represent an appropriate treatment option for severe ankle fractures in patients suffering from relevant co-morbidities. Prospective randomized trials are warranted to prove superiority of locking plates for treatment of geriatric ankle fractures. Level 3: Retrospective case- control study.

Cement augmentation of glenoid baseplate screws does not improve primary stability in reversed shoulder arthroplasty: A cadaveric study.

INTRODUCTION: Cuff tear arthritis and complex proximal humeral fractures are common pathologies that are frequently addressed by the implantation of a reversed shoulder prosthesis. The present cadaveric study aimed to analyze the effect of cement augmentation of the glenoid component on the primary stability in geriatric patients. HYPOTHESIS: Cement augmentation of glenoid baseplate screws has an influence on primary stability in reversed shoulder arthroplasty (RSA). MATERIALS AND METHODS: Glenoid base plates (Delta Xtend, DePuy Synthes, Westchester, USA) were implanted in 6 pairs of formalin-fixated scapulae of 4 female and 2 male donors (average age 83 years). Two angle stable screws were placed at the superior and inferior position. Cement augmentation was performed with 2ml bone cement (Kyphon, Medtronic, Minneapolis, USA) per screw in right specimens. Afterwards, biomechanical testing with 600 to 1000N (100 cycles) at a 65° abduction angle was performed. Finally, a load-to-failure analysis was conducted. RESULTS: No implant loosening was observed during cyclic tests from 600N to 1000N. In addition no difference in the plastic deformation was detected at 600N (p=0.301), 700N (p=0.522), 800N (p=0.480), 900N (p=0.521) and 1000N (p=0.748). Load-to-failure analyses revealed implant loosening at 3314N (SD 823N) in the cement-augmented implants and at 3059N (SD 974N) in scapulae with non-cemented screws (p=0.522). DISCUSSION: Cement-augmented fixation of the glenoid component did not result in an increased primary stability in this study. Thus, the application of cement should be critically assessed considering associated risks and increased costs. LEVEL OF PROOF: Basic science study, controlled laboratory study.

Panobinostat mediated cell death: a novel therapeutic approach for osteosarcoma.

Osteosarcoma is an aggressive cancer with a poor long term prognosis. Neo-adjuvant poly-chemotherapy followed by surgical resection remains the standard treatment, which is restricted by multi-drug resistance. If first-line therapy fails, disease control and patient survival rate drop dramatically. We aimed to identify alternative apoptotic mechanisms induced by the histone deacetylase inhibitor panobinostat in osteosarcoma cells. Saos-2, MG63 and U2-OS osteosarcoma cell lines, the immortalized human osteoblast line hFOB and the mouse embryo osteoblasts (MC3T3-E1) were treated with panobinostat. Real time viability and FACS confirmed the cytotoxicity of panobinostat. Cell stress/death related factors were analysed by RT-qPCR and western blot. Cell morphology was assessed by electron microscopy. 10 nM panobinostat caused cell viability arrest and death in all osteosarcoma and osteoblast cells. P21 up-regulation was observed in osteosarcoma cells, while over-expression of p73 was restricted to Saos-2 (TP53-/-). Survivin and Bcl-2 were suppressed by panobinostat. Endoplasmic reticulum (ER) stress markers BiP, CHOP, ATF4 and ATF6 were induced in osteosarcoma cells. The un-spliced Xbp was no further detectable after treatment. Autophagy players Beclin1, Map1LC3B and UVRAG transcripts over-expressed after 6 hours. Protein levels of Beclin1, Map1LC3B and p62 were up-regulated at 72 hours. DRAM1 was stable. Electron micrographs revealed the fragmentation and the disappearance of the ER and the statistically significant increase of autophagosome vesiculation after treatment. Panobinostat showed a synergistic suppression of survival and promotion of cell death in osteosarcoma cells. Panobinostat offers new perspectives for the treatment of osteosarcoma and other malignant bone tumours.

Standardised pre-operative diagnostics and treatment of peripheral arterial disease reduce wound complications in geriatric ankle fractures.

PURPOSE: The aim of this study was to evaluate a standardised algorithm to assess and treat impaired limb perfusion prior to surgical fixation of geriatric ankle fractures and determine the prevalence of peripheral arterial disease (PAD) in geriatric patients presenting with ankle fractures. METHODS: Eighty-four patients >65 years pre-operatively diagnosed and treated according to an algorithm (study group) were compared with 84 patients diagnosed and treated before the algorithm was introduced (control group). RESULTS: In 14 patients of the study group, clinical noninvasive examination revealed signs of relevant PAD, which was confirmed with computed tomographic angiography (CTA) in nine patients, all of whom had successful angioplasty prior to surgical fixation of the ankle fracture. In three of these patients, PAD had previously been diagnosed. After standardised diagnostics and treatment of malperfusion, a significantly reduced overall and, particularly, wound complication rate was found. CONCLUSION: PAD is an underdiagnosed condition in geriatric patients presenting with ankle fractures. This study underlines the relevance of limb perfusion for adequate wound healing in geriatric ankle fractures. Therefore, special attention should be paid to diagnose and-if indicated-optimise limb perfusion prior to surgical fixation of geriatric ankle fractures.

Multiple Trauma and Emergency Room Management.

BACKGROUND: The care of severely injured patients remains a challenge. Their initial treatment in the emergency room is the essential link between first aid in the field and definitive in-hospital treatment. METHODS: We present important elements of the initial in-hospital care of severely injured patients on the basis of pertinent publications retrieved by a selective search in PubMed and the current German S3 guideline on the care of severely and multiply traumatized patients, which was last updated in 2016. RESULTS: The goal of initial emergency room care is the rapid recognition and prompt treatment of acutely life-threatening injuries in the order of their priority. The initial assessment includes physical examination and ultrasonography according to the FAST concept (Focused Assessment with Sonography in Trauma) for the recognition of intraperitoneal hemorrhage. Patients with penetrating chest injuries, massive hematothorax, and/or severe injuries of the heart and lungs undergo emergency thoracotomy; those with signs of hollow viscus perforation undergo emergency laparotomy. If the patient is hemo - dynamically stable, the most important diagnostic procedure that must be performed is computerized tomography with contrast medium. Therapeutic decision-making takes the patient's physiological parameters into account, along with the overall severity of trauma and the complexity of the individual injuries. Depending on the severity of trauma, the immediate goal can be either the prompt restoration of organ structure and function or so-called damage control surgery. The latter focuses, in the acute phase, on hemostasis and on the avoidance of secondary damage such as intra-abdominal contamination or compartment syndrome. It also involves the temporary treatment of fractures with external fixation and the planning of definitive care once the patient's organ functions have been securely stabilized. CONCLUSION: The care of the severely injured patient should be performed in structured fashion according to the A-B-C-D-E scheme, which involves the securing of the airway, breathing, and circulation, the recognition of neurologic deficits, and whole-body examination by the interdisciplinary team.

Relationship of Prolonged Operative Time and Comorbidities With Complications After Geriatric Ankle Fractures.

BACKGROUND: The incidence of geriatric ankle fractures has increased during the last few decades. In contrast to younger patients, increased complication rates have been observed. Thus, the goal of the present study was to identify risk factors for perioperative complications following open reduction and internal fixation of geriatric ankle fractures. METHODS: Two hundred thirty-seven patients over the age of 65 years (mean, 72.5 ± 6.1 years) treated for ankle fractures in our institution between 2004 and 2014 were included. Complications associated with operative treatment as well as complications requiring revision surgery were analyzed. In a multivariate analysis, risk factors were determined. RESULTS: In 68 patients (28.7%), 74 complications were documented. The most common complications were impaired wound healing and operative site infections. The multivariate analysis revealed that the operative time was the only independent risk factor for the development of a complication. The operative time as well as the presence of an open fracture represented risk factors for needing revision surgery. Comorbidities did not influence the development of complications. CONCLUSION: The operative management of geriatric ankle fractures was associated with a high complication rate. In the present study, the operative time was the only modifiable factor for the development of a complication that required revision surgery. During preoperative preparation, we believe that perfusion of the affected limb should be optimized to reduce the incidence of wound complications. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Association of an In-House Blood Bank with Therapy and Outcome in Severely Injured Patients: An Analysis of 18,573 Patients from the TraumaRegister DGU®.

INTRODUCTION: Hemorrhagic shock remains one of the most common causes of death in severely injured patients. It is unknown to what extent the presence of a blood bank in a trauma center influences therapy and outcome in such patients. MATERIAL AND METHODS: We retrospectively analyzed prospectively recorded data from the TraumaRegister DGU® and the TraumaNetzwerk DGU®. Inclusion criteria were Injury Severity Score (ISS) ≥ 16, primarily treated patients, and hospital admission 2 years before or after the audit process. RESULTS: Complete data sets of 18,573 patients were analyzed. Of 457 hospitals included, 33.3% had an in-house blood bank. In trauma centers with a blood bank (HospBB), packed red blood cells (PRBCs) (21.0% vs. 17.4%, p < 0.001) and fresh frozen plasma (FFP) (13.9% vs. 10.2%, p <0.001) were transfused significantly more often than in hospitals without a blood bank (Hosp0). However, no significant difference was found for in-hospital mortality (standard mortality ratio [SMR, 0.907 vs. 0.945; p = 0.25). In patients with clinically apparent shock on admission, no difference of performed transfusions were present between HospBB and Hosp0 (PRBCs, 51.4% vs. 50.4%, p = 0.67; FFP, 32.7% vs. 32.7%, p = 0.99), and no difference in in-hospital mortality was observed (SMR, 0.907 vs. 1.004; p = 0.21). DISCUSSION: In HospBB transfusions were performed more frequently in severely injured patients without positively affecting the 24h mortality or in-house mortality. Easy access may explain a more liberal transfusion concept.

Is there a benefit of proximal locking screws in osteoporotic distal radius fractures? - A biomechanical study.

INTRODUCTION: The distal radial fracture is a common fracture and frequently seen in geriatric patients. During the last years, volar plating has become a popular treatment option. While the application of locking screws at the distal fragment is widely accepted, there is no evidence for their use at the radial shaft. MATERIALS AND METHODS: In six osteoporotic pairs of matched human cadaver radii an extra-articular model creating an AO 23-A2.1 fracture was employed. Osteosynthesis were performed using the APTUS 2.5 Adaptive TriLock Distal Radius System (Medartis AG) with locking (LS) or non-locking screws (NLS) for proximal fixation. Biomechanical testing was performed in a staircase fashion: starting with 50 cycles at 200N, the load was continuously increased by 50N every 80 cycles up to a maximum force of 400N. Finally, load to failure was analyzed with failure defined as sudden loss of force measured (20%) or major deformation of the radii (10mm). RESULTS: At 200N, 250N, 300N, 400N and load to failure, the NLS group showed a higher degree of elastic modulus. In contrast, the LS group showed higher elastic modulus at 350N. Maximum force was higher in the LS group without reaching statistical significance. Reasons for loss of fixation were longitudinal shaft fractures, horizontal peri-implant fractures and distal cutting out. No difference was seen between the two groups concerning the development of the above mentioned complications. CONCLUSION: Our study did not show biomechanical superiority for distal radius fracture fixation by using locking screws in the proximal holes in an osteoporotic cadaver study. At load to failure, longitudinal shaft fractures and peri-implant fractures seemed to be a more relevant problem rather than failure of the proximal fixation.

The osseous morphology of nondegenerated shoulders shows no side-related differences in elderly patients: an analysis of 102 computed tomography scans.

BACKGROUND: A precise understanding of glenohumeral anatomy is required to optimize preoperative planning in shoulder joint arthroplasty, which is difficult in the presence of degenerative disease. In unilateral disease, the contralateral shoulder can be used as a representation of normal anatomy; however, intrasubject differences in shoulder morphology have not been investigated. METHODS: A retrospective study of all patients aged >65 years who received whole body computed tomography at our trauma center from 2010 through 2014 was conducted. Right and left shoulder computed tomography scans were examined, and the following anatomic parameters were measured: humeral head diameter in anteroposterior and axial views, glenoid diameter in anteroposterior and axial views, glenoid surface, scapula neck depth, neck-shaft angle, glenoid inclination, glenoid/head ratio, and glenoid version. Patients with inadequate scan quality, osseous lesions, pre-existing anatomic abnormality, or metallic implant at the shoulder region and significant osteoarthritis were excluded. RESULTS: The study analyzed 102 shoulders of 51 patients. Mean age was 71.4 ± 8.2 years. Humeral head and glenoid diameters, scapula neck depth (right, 36 ± 8 mm; left, 36 ± 7 mm; P = .684), glenoid/head ratio (right, 0.6 ± 0.1; left, 0.6 ± 0.0; P = .961), and glenoid surface (right, 790 ± 152 mm(2); left, 754 ± 134 mm(2); P = .215) showed no significant side-related differences. In addition, no significant difference was found regarding the neck-shaft angle (P = .211) and glenoid anteversion or retroversion (right, 65% [n = 33] anteversion and 35% [n = 18] retroversion; left, 69% [n = 35] anteversion and 31% [n = 16] retroversion; P = .417). CONCLUSION: There are no significant side-dependent differences in the osseous anatomy of the glenohumeral joint. In patients with unilateral shoulder degeneration, the contralateral shoulder can provide reference values during the planning of shoulder replacement surgery.

Agreement Between Proximal Femoral Geometry and Component Design in Total Hip Arthroplasty: Implications for Implant Choice.

BACKGROUND: The present study aimed to analyze the agreement between proximal femoral geometry of adult hips and femoral component design in total hip arthroplasty. METHODS: Anatomical femoral offset (FOAnat) and the anatomical neck-shaft angle (NSAAnat) of 800 adult hips were measured by computed tomography scans, and anatomical femoral neck height (FHAnat) was calculated. Corresponding best-fit implants of the most common hip system (standard, high offset and varus variant) were identified for each hip. Finally, the precision of the best possible anatomic reconstruction was assessed. RESULTS: The mean FOAnat was 38.0 mm (range: 19.8-57.9 mm, standard deviation [SD]: 6.4 mm), the mean NSAAnat was 130.8° (range: 107.1°-151.9°; SD: 6.5°), and the mean FHAnat was 32.6 mm (range: 14.4-52.0 mm; SD: 5.5 mm). In 450 (56.3%) hips, the standard variant was identified to be the best-fit implant, followed by the varus (n = 282, 35.3%) and the high offset (n = 68, 8.5%) variants. The mean minimal distance from the best-fit implant was 4.5 mm (range: 0.1-20.2 mm, SD: 3.4 mm). Excellent agreement (distance: <2 mm) between hip anatomy and best-fit implant was found in 203 (25.4%) hips, combined excellent and acceptable agreement (distance: <6 mm) in 569 (71.1%) hips, whereas 213 (28.9%) hips were graded as poor (distance: ≥6 mm). CONCLUSION: The present study revealed a mismatch between proximal femoral anatomy of a relevant proportion of adult hips and implant geometry of the most common femoral component in total hip arthroplasty.

The Modified Femoral Neck-Shaft Angle: Age- and Sex-Dependent Reference Values and Reliability Analysis.

Background. The femoral neck-shaft angle (NSA) is of high importance for the diagnostics and treatment of various conditions of the hip. However, rotational effects limit its precision and applicability using plain radiographs. This study introduces a novel method to measure the femoral NSA: the modified NSA (mNSA), possibly being less susceptible against rotational effects compared to the conventional NSA. Patients and Methods. The method of measurement is described and its applicability was tested in 400 pelvis computed tomography scans (800 hips). Age- and gender-dependent reference values are given and intra- and interrater reliability are analyzed. Results. The mean age of all 400 patients (800 hips) was 54.32 years (18-100, SD 22.05 years). The mean mNSA was 147.0° and the 95% confidence interval was 146.7°-147.4°. Differences of the mNSA between sexes, age groups, and sides were nonsignificant. The absolute difference between NSA and mNSA was 16.3° (range 3-31°; SD 4.4°); the correlation was high (0.738; p < 0.001). Overall, the intra- and interrater reliability were excellent for the mNSA. Interpretation. We introduced a novel concept for the analysis of the neck-shaft angle. The high reliability of the measurement has been proven and its robustness to hip rotation was demonstrated.

Stimulation with bone morphogenetic protein-2 (BMP-2) enhances bone-tendon integration in vitro.

PURPOSE: Preclinical studies have reported that bone morphogenetic protein (BMP)-2 promotes bone-tendon healing following anterior cruciate ligament reconstruction. We examined the region-specific effects of BMP-2 on osteoblast and fibroblast differentiation in a highly standardized murine in vitro co-culture model of bone-tendon integration. MATERIALS AND METHODS: We used quantitative PCR to measure the dose- and time-dependent influence of BMP-2 on the expression of alkaline phosphatase, osteocalcin, collagen type 1 (alpha 1 chain), runt-related transcription factor 2, osteopontin, collagen type 1 (alpha 2 chain), collagen type 5 (alpha 1 chain), decorin, fibromodulin, mohawk homeobox, bone morphogenetic protein receptor, type 1A, bone morphogenetic protein receptor, type 2, and Noggin in the osteoblast, interface, and fibroblast regions of a co-culture model of the murine preosteoblast cell line MC3T3-E1 and the fibroblast cell line 3T6. RESULTS: Stimulation with BMP-2 resulted in a significant upregulation of alkaline phosphatase (p < 0.001), osteocalcin (p < 0.001), collagens (p < 0.001), runt-related transcription factor 2 (p < 0.05), and osteopontin (p < 0.001) expression in the osteoblast region. In the interface region, BMP-2 exposure led to dose- and time-dependent upregulation of alkaline phosphatase (p < 0.001), osteocalcin (p < 0.001), osteopontin (p < 0.001), runt-related transcription factor 2 (p < 0.001), and markers of extracellular matrix production (p < 0.001). Both BMP receptors showed a significant BMP-2-dependent upregulation at the interface region, and Noggin was downregulated at the osteoblast and interface region following BMP-2 exposure. CONCLUSIONS: Exposure to BMP-2 upregulated the expression of genes associated with bone-tendon integration in vitro, suggesting the stimulation of transdifferentiation processes at the interface and fibroblast regions as well as the induction of positive feedback mechanisms. Further studies will be needed to establish BMP-2 dose and treatment algorithms following tendon reinsertion and reconstruction.

Calibration Marker Position in Digital Templating of Total Hip Arthroplasty.

BACKGROUND: We report a mathematical method to assess the vertical and horizontal positions of spherical radiopaque objects of known size in conventional radiographs. METHODS: The reliability and validity of the method were tested in an experimental setting and applied to 100 anteroposterior pelvic radiographs with external calibration markers and unilateral total hip arthroplasty (THA). RESULTS: We found excellent reliabilities; intraclass correlation coefficients for interobserver and intraobserver reliabilities were 0.999-1.000 (P = .000). The mean normal height of THA was 198 mm (range: 142-243 mm, standard deviation: 18 mm) above the detector. Vertical and horizontal external marker positions differed significantly from the true hip center (THA; P < .001 and P = .017). CONCLUSION: This method could enhance patient safety by enabling automated detection of malpositioned calibration markers by templating software.