Max Ettinger

Google Glass for documentation of medical findings: evaluation in forensic medicine.

Background Google Glass is a promising premarket device that includes an optical head-mounted display. Several proof of concept reports exist, but there is little scientific evidence regarding its use in a medical setting. Objective The objective of this study was to empirically determine the feasibility of deploying Glass in a forensics setting. Methods Glass was used in combination with a self-developed app that allowed for hands-free operation during autopsy and postmortem examinations of 4 decedents performed by 2 physicians. A digital single-lens reflex (DSLR) camera was used for image comparison. In addition, 6 forensic examiners (3 male, 3 female; age range 23-48 years, age mean 32.8 years, SD 9.6; mean work experience 6.2 years, SD 8.5) were asked to evaluate 159 images for image quality on a 5-point Likert scale, specifically color discrimination, brightness, sharpness, and their satisfaction with the acquired region of interest. Statistical evaluations were performed to determine how Glass compares with conventionally acquired digital images. Results All images received good (median 4) and very good ratings (median 5) for all 4 categories. Autopsy images taken by Glass (n=32) received significantly lower ratings than those acquired by DSLR camera (n=17) (region of interest: z=–5.154, P<.001; sharpness: z=–7.898, P<.001; color: z=–4.407, P<.001, brightness: z=–3.187, P=.001). For 110 images of postmortem examinations (Glass: n=54, DSLR camera: n=56), ratings for region of interest (z=–8.390, P<.001) and brightness (z=–540, P=.007) were significantly lower. For interrater reliability, intraclass correlation (ICC) values were good for autopsy (ICC=.723, 95% CI .667-.771, P<.001) and postmortem examination (ICC=.758, 95% CI .727-.787, P<.001). Postmortem examinations performed using Glass took 42.6 seconds longer than those done with the DSLR camera (z=–2.100, P=.04 using Wilcoxon signed rank test). The battery charge of Glass quickly decreased; an average 5.5% (SD 1.85) of its battery capacity was spent per postmortem examination (0.81% per minute or 0.79% per picture). Conclusions Glass was efficient for acquiring images for documentation in forensic medicine, but the image quality was inferior compared to a DSLR camera. Images taken with Glass received significantly lower ratings for all 4 categories in an autopsy setting and for region of interest and brightness in postmortem examination. The effort necessary for achieving the objectives was higher when using the device compared to the DSLR camera thus extending the postmortem examination duration. Its relative high power consumption and low battery capacity is also a disadvantage. At the current stage of development, Glass may be an adequate tool for education. For deployment in clinical care, issues such as hygiene, data protection, and privacy need to be addressed and are currently limiting chances for professional use.

PSI kinematic versus non-PSI mechanical alignment in total knee arthroplasty: a prospective, randomized study

PurposeKinematic alignment in TKA is supposed to restore function by aligning the components to the premorbid flexion–extension axis instead of altering the joint line and natural kinematic axes of the knee. The purpose of this study was to compare mechanically aligned TKA to kinematic alignment.MethodsIn this study, 200 patients underwent TKA and were randomly assigned to 2 groups: 100 TKAs were performed using kinematic alignment with custom-made cutting guides in order to complete cruciate-retaining TKA; the other 100 patients underwent TKA that was manually performed using mechanical alignment. The WOMAC and combined Knee Society Score (KSS), as well as radiological alignment, were determined as outcome parameters at the 12-month endpoint.ResultsWOMAC and KSS significantly improved in both groups. There was a significant difference in both scores between groups in favour of kinematic alignment. Although the kinematic alignment group demonstrated significantly better overall results, more outliers with poor outcomes were also seen in this group. A correlation between post-operative alignment deviation from the initial plan and poor outcomes was also noted. The most important finding of this study is that applying kinematic alignment in TKA achieves comparable results to mechanical alignment in TKA. This study also shows that restoring the premorbid flexion–extension axis of the knee joint leads to better overall functional results.ConclusionKinematic alignment is a favourable technique for TKA.Clinical relevanceThe kinematic alignment idea might be a considerable alternative to mechanical alignment in the future.Level of evidenceII.

Biomechanical Properties of Suture Anchor Repair Compared With Transosseous Sutures in Patellar Tendon Ruptures A Cadaveric Study

Background: Ruptures of the patellar tendon are debilitating injuries requiring surgical repair. Reliable data about the most appropriate suture technique and suture material are missing. The standard procedure consists of refixing the tendon with sutures in transpatellar tunnels, sometimes combined with augmentation. Hypothesis: Suture anchors provide at least equal results concerning gap formation during cyclic loading and ultimate failure load compared with transosseous suture repair. Study Design: Controlled laboratory study. Methods: A total of 30 human cadaveric patellar tendons underwent tenotomy followed by repair with 5.5-mm titanium suture anchors, 5.5-mm resorbable hydroxyapatite suture anchors, or transpatellar suture tunnels with No. 2 Ultrabraid and the Krackow whipstitch technique. Biomechanical analysis included pretensioning the constructs at 20 N for 30 seconds and then cyclic loading of 250 cycles between 20 and 100 N at 1 Hz in a servohydraulic testing machine with measurement of elongation. After this, ultimate failure load and failure mode analysis was performed. Results: Compared with transosseous sutures, tendon repairs with suture anchors yielded significantly less gap formation during cyclic loading (P < .05) and resisted significantly higher ultimate failure loads (P < .05). Common failure mode was pullout of the eyelet within the suture anchor in the hydroxyapatite anchor group and rupture of the suture in the titanium anchor group and—at lower load to failure—in the transosseous group. Conclusion: Patellar tendon repair with suture anchors yields significantly better biomechanical results than repair with the commonly applied transosseous sutures. Clinical Relevance: These findings may be of relevance for future clinical treatment of patellar tendon ruptures. Randomized controlled clinical trials comparing suture anchors to transosseous suture repair are desirable.

Circulating Biomarkers for Discrimination Between Aseptic Joint Failure, Low-Grade Infection And High-Grade Septic Failure

BACKGROUND Late-onset chronic (low-grade) periprosthetic joint infections are often accompanied by unspecific symptoms, false-negative cultures or nonspecific low values of serum biomarkers. This may lead to the unintended implantation of a revision prosthesis into an infected surgical site with the risk of short-term failure developing again. Conversely, false diagnosis of joint infection may result in multistage revision procedures, which expose the patient to unnecessary surgical procedures and inappropriate antibiotic treatment. Here, we investigated whether circulating biomarkers can preoperatively distinguish between aseptic prosthesis loosening and low-grade joint infection, and which biomarker combinations are most accurate. METHODS Inclusion criteria for the study were indication for revision arthroplasty due to aseptic implant failure, acute high-grade infection, or (suspected) low-grade infection. C-reactive protein (CRP), procalcitonin, tumor necrosis factor α, interleukin 6 (IL-6), interleukin 10, and lipopolysaccharide binding protein were assessed preoperatively in the serum of 98 adult patients. RESULTS The classification tree method revealed IL-6 and CRP as the most suitable biomarker combination for the discrimination of aseptic loosening vs low-grade joint infection. The combination of IL-6 >5.12 pg/mL and CRP >0.3 mg/dL correctly identified 15 of 16 patients as having low-grade infection (94%) whereas just one patient was aseptic (6%). CONCLUSIONS This is the first comprehensive prospective clinical study to our knowledge investigating the significance of a combined biomarker approach in differentiating between aseptic prosthesis loosening and low-grade joint infection. CRP plus IL-6 seems to be the most helpful combination for preoperative discrimination of aseptic loosening vs low-grade joint infection.

Synovial C-reactive protein as a marker for chronic periprosthetic infection in total hip arthroplasty

The aim of this study was to assess the role of synovial C-reactive protein (CRP) in the diagnosis of chronic periprosthetic hip infection. We prospectively collected synovial fluid from 89 patients undergoing revision hip arthroplasty and measured synovial CRP, serum CRP, erythrocyte sedimentation rate (ESR), synovial white blood cell (WBC) count and synovial percentages of polymorphonuclear neutrophils (PMN). Patients were classified as septic or aseptic by means of clinical, microbiological, serum and synovial fluid findings. The high viscosity of the synovial fluid precluded the analyses in nine patients permitting the results in 80 patients to be studied. There was a significant difference in synovial CRP levels between the septic (n = 21) and the aseptic (n = 59) cohort. According to the receiver operating characteristic curve, a synovial CRP threshold of 2.5 mg/l had a sensitivity of 95.5% and specificity of 93.3%. The area under the curve was 0.96. Compared with serum CRP and ESR, synovial CRP showed a high diagnostic value. According to these preliminary results, synovial CRP may be a useful parameter in diagnosing chronic periprosthetic hip infection.

Access to the Hip Joint From Standard Arthroscopic Portals: A Cadaveric Study

PURPOSE Our purpose was to study and describe the areas of the hip joint that can be safely visualized and operated on using a variety of portals for the central and peripheral compartments. METHODS Twelve hip joints in 6 human cadavers were examined through 9 different central and peripheral arthroscopic portals. Markings of the accessible areas within the joint were made through an arthroscope. Dissection of the cadavers was carried out for final evaluation of the visible areas and those accessible for instruments. During dissection, anatomic proximity of the portals to relevant neurovascular structures was measured. RESULTS The central compartment was sufficiently accessible using the anterior, anterolateral, and posterolateral portals, with slight limitations in the posteromedial corner. A more medial portal did not offer substantial advantages regarding accessibility but decreased the safety distance to the femoral nerve. With regard to the peripheral compartment, the combination of the anterolateral and posterolateral portals allowed visualization of most of the joint. It was observed that the structure at highest risk of injury for the central anterior and the peripheral anterolateral portals was the lateral femoral cutaneous nerve. CONCLUSIONS In hip arthroscopy, the use of the standard anterior, anterolateral, and posterolateral portals allows proper accessibility of the central compartment, with slight limitations in the posteromedial corner. A more medial portal is not recommended with regard to its risk-benefit ratio. The peripheral compartment of the hip joint is sufficiently visible using the anterolateral and posterolateral portals. For treatment of specific pathologic conditions, a variation of these portals improves surgical accessibility. The anatomic structure at highest risk of injury during hip arthroscopy is the lateral femoral cutaneous nerve. CLINICAL RELEVANCE The general objectives of this study were to prepare surgeons to develop appropriate concepts of surgery and to facilitate preoperative planning.

Preliminary Results of a New Test for Rapid Diagnosis of Septic Arthritis with Use of Leukocyte Esterase and Glucose Reagent Strips

BACKGROUND Most currently used tools to diagnose septic arthritis are either not readily available or fail to provide real-time results. Reagent strip tests have identified infections in various body fluids. We hypothesized that combined leukocyte esterase and glucose strip tests can aid in diagnosing septic arthritis in native synovial fluid because (1) leukocyte esterase concentrations would be elevated at the infection site because of secretion by recruited neutrophils, and (2) glucose concentrations would be reduced because of bacterial metabolism. METHODS We prospectively investigated synovial fluid from consecutive patients with an atraumatic joint effusion who underwent arthrocentesis in our emergency department during a one-year period. Leukocyte esterase and glucose strip tests were performed on the synovial fluid. Synovial fluid leukocyte count, crystal analysis, Gram staining, culture, and glucose concentration results were also assessed. RESULTS Nineteen fluids were classified as septic and 127 as aseptic. Considering septic arthritis to be present when the leukocyte esterase reading was positive (++ or +++) and the glucose reading was negative (-) yielded a sensitivity of 89.5% (95% confidence interval [CI], 66.9% to 98.7%), specificity of 99.2% (95% CI, 95.7% to 99.9%), positive predictive value of 94.4% (95% CI, 72.7% to 99.9%), negative predictive value of 98.4% (95% CI, 94.5% to 99.8%), positive likelihood ratio of 114, and negative likelihood ratio of 0.11. The synovial leukocyte counts and polymorphonuclear cell percentages were consistent with the semiquantitative readings on the leukocyte esterase strip tests, and the glucose concentrations were consistent with the glucose strip test results. CONCLUSIONS Combined leukocyte esterase and glucose strip tests can be a useful additional tool to help confirm or rule out a diagnosis of septic arthritis.

Influence on Therapeutic Decision Making of SPECT-CT for Different Regions of the Foot and Ankle

Background. Single-photon emission computed tomography and computed tomography (SPECT-CT) has a high impact on diagnosis and treatment decision of different joints. The aim of this study was to evaluate whether there is a different gain of SPECT-CT for different foot regions. Material and Methods. We retrospectively identified 86 patients who received a SPECT-CT of the foot and ankle between April 2011 and December 2012. We divided all patients into the following subgroups: ankle (group 1), subtalar (group 2), Chopart (group 3), and Lisfranc (group 4). The local ethical committee approved the study. Results. The clinical treatment decision was changed based on SPECT-CT results in 64.5% of group 1, 65.2% of group 2, and 75% each of groups 3 and 4. Eighty patients (93%) had pain relief after treatment based on SPECT-CT. The overall SPECT-CT sensitivity was 0.94 and the specificity was 0.57. The positive and negative predictive values were 0.87 and 0.75, respectively. Conclusion. The impact of SPECT-CT on treatment decision is slightly higher in diseases of the Chopart and Lisfranc joints than in the upper ankle and subtalar joints. The additional information has a clinical relevance due to the high rate of pain relief by treatment based on SPECT-CT diagnosis.

Short-stem hip arthroplasty in osteonecrosis of the femoral head.

IntroductionOsteonecrosis of the femoral head (ONFH) is a locally destructive and complex disorder. Without treatment, infraction of the femoral head is likely. There is also a lack of consensus in the literature about the most appropriate arthroplasty method in patients with progressive ONFH. During the last decade, the number of short-stem prostheses has increased. Some short-stem designs have a metaphyseal anchorage. It is questionable whether ONFH represents a risk factor for failure after implantation of short stems. The aim of this study was to review existing literature regarding the outcome of short-stem arthroplasty in ONFH and to present the pros and cons of short-stem hip arthroplasty in osteonecrosis of the femoral head.Materials and methodsThis review summarises existing studies on short-stem hip arthroplasty in osteonecrosis of the femoral head.ResultsFew studies have analysed the clinical and radiological outcome of short-stem THA in patients with ONFH. Only a handful of studies present clinical and radiological outcome after implantation of a short-stem arthroplasty in patients with the underlying diagnosis of osteonecrosis of the femoral head.ConclusionThe short- to medium-term results show predominantly good outcomes. However, due to differences in the design of short stems and their fixation, it is hard to draw a general conclusion. Short stems with primary diaphyseal fixation do not reveal a high increased risk of failed osseointegration or loosening. For designs with a primary metaphyseal anchorage, an MRI should be conducted to exclude that the ostenecrosis exceeds the femoral neck.

Update on the etiology of revision TKA — Evident trends in a retrospective survey of 1449 cases

BACKGROUND A working and complete knowledge of the different causes of dysfunction and pain after TKA is essential for the ability to correctly determine the cause of failure and to address this problem specifically. The purpose of this study was to update the etiology of implant failure. New diagnosis and current trends should be displayed. METHODS All TKA revisions performed in our institution between 2001 and 2010 were reviewed retrospectively. Patient demographics and the precise indication for the surgery were documented. Descriptive statistical analyses and association analyses of both the diagnosis and patient demographics were performed. RESULTS Within our collective of 1449 revision TKA a total of 40 different pathologies leading to revision surgery were identified and categorized. Overall 68.5% of the revisions were categorized aseptic, 31.5% as septic implant failure. Some recently debated diagnoses like low-grade-infection showed a high increase in incidence whereas classic failure mechanisms like polyethylene wear showed a decrease over the time. CONCLUSION We believe that this study successfully updates the current knowledge of different failure mechanisms in revision TKA, which have to be considered on dysfunction or pain after surgery. We were able to evaluate the clinical relevance of each pathology and could shift from implant related problems like wear to more surgical problems like instability and or malalignment over the last years. With a higher alertness to chronic low-grade-infections the incidence of infection is even increasing. LEVEL OF EVIDENCE Level II, economic and decision analysis.