Philip P. Roessler

Electrospun PLLA Nanofiber Scaffolds and Their Use in Combination with BMP-2 for Reconstruction of Bone Defects

Introduction Adequate migration and differentiation of mesenchymal stem cells is essential for regeneration of large bone defects. To achieve this, modern graft materials are becoming increasingly important. Among them, electrospun nanofiber scaffolds are a promising approach, because of their high physical porosity and potential to mimic the extracellular matrix (ECM). Materials and Methods The objective of the present study was to examine the impact of electrospun PLLA nanofiber scaffolds on bone formation in vivo, using a critical size rat calvarial defect model. In addition we analyzed whether direct incorporation of bone morphogenetic protein 2 (BMP-2) into nanofibers could enhance the osteoinductivity of the scaffolds. Two critical size calvarial defects (5 mm) were created in the parietal bones of adult male Sprague-Dawley rats. Defects were either (1) left unfilled, or treated with (2) bovine spongiosa, (3) PLLA scaffolds alone or (4) PLLA/BMP-2 scaffolds. Cranial CT-scans were taken at fixed intervals in vivo. Specimens obtained after euthanasia were processed for histology, histomorphometry and immunostaining (Osteocalcin, BMP-2 and Smad5). Results PLLA scaffolds were well colonized with cells after implantation, but only showed marginal ossification. PLLA/BMP-2 scaffolds showed much better bone regeneration and several ossification foci were observed throughout the defect. PLLA/BMP-2 scaffolds also stimulated significantly faster bone regeneration during the first eight weeks compared to bovine spongiosa. However, no significant differences between these two scaffolds could be observed after twelve weeks. Expression of osteogenic marker proteins in PLLA/BMP-2 scaffolds continuously increased throughout the observation period. After twelve weeks osteocalcin, BMP-2 and Smad5 were all significantly higher in the PLLA/BMP-2 group than in all other groups. Conclusion Electrospun PLLA nanofibers facilitate colonization of bone defects, while their use in combination with BMP-2 also increases bone regeneration in vivo and thus combines osteoconductivity of the scaffold with the ability to maintain an adequate osteogenic stimulus.

The anterolateral ligament (ALL) and its role in rotational extra-articular stability of the knee joint: a review of anatomy and surgical concepts.

The anterolateral ligament of the knee (ALL) has caused a lot of rumors in orthopaedics these days. The structure that was first described by Segond back in 1879 has experienced a long history of anatomic descriptions and speculations until its rediscovery by Claes in 2013. Its biomechanical properties and function have been examined recently, but are not yet fully understood. While the structure seems to act as a limiter of internal rotation and lateral meniscal extrusion its possible proprioceptive effect remains questionable. Its contribution to the pivot shift phenomenon has been uncovered in parts, therefore it has been recognized that a concomitant anterolateral stabilization together with ACL reconstruction may aid in prevention of postoperative instability after severe ligamentous knee damages. However, there are a lot of different methods to perform this procedure and the clinical outcome has yet to be examined. This concise review will give an overview on the present literature to outline the long history of the ALL under its different names, its anatomic variances and topography as well as on histologic examinations, imaging modalities, arthroscopic aspects and methods for a possible anterolateral stabilization of the knee joint.

Improvement in outcomes after implantation of a novel polyurethane meniscal scaffold for the treatment of medial meniscus deficiency.

Pain 47 ± 14.5 75 ± 17.7 p < 0.0001 82 ± 17.4 p < 0.0001 83 ± 18.6 p < 0.0001 Symptom 60 ± 16.2 67 ± 18.5 p = 0.0091 85 ± 9.7 p < 0.0001 81 ± 13.4 p = 0.0003 ADL 53 ± 16.0 85 ± 14.5 p < 0.0001 88 ± 13.0 p < 0.0001 91 ± 14.7 p < 0.0001 Sport/Rec 26 ± 20.5 60 ± 25.3 p = 0.0001 68 ± 24.0 p < 0.0001 66 ± 28.5 p < 0.0001 QOL 28 ± 16.6 55 ± 26.9 p = 0.0007 67 ± 20.4 p < 0.0001 63 ± 18.9 p < 0.0001 KSS Function score 61 ± 22.2 87 ± 10.2 p = 0.0001 89 ± 15.7 p = 0.0001 96 ± 7.9 p < 0.0001 Knee score 65 ± 9.4 89 ± 13.1 p < 0.0001 87 ± 14.1 p < 0.0001 88 ± 12.4 p < 0.0001 UCLA 5.4 ± 1.8 6.1 ± 1.8 n.s. 6.5 ± 2.1 n.s. 7.3 ± 1.8 p = 0.0035 VAS 5.1 ± 2.0 2.1 ± 2.4 p = 0.0004 1.8 ± 2.3 p < 0.0001 1.5 ± 2.1 p < 0.0001

Influence of smoking on spinal fusion after spondylodesis surgery: A comparative clinical study

BACKGROUND Smoking is a risk factor in the process of bone healing after lumbar spondylodesis, often associated with complications that occur intraoperatively or during follow-up periods. OBJECTIVE To assess if smokers yield worse results concerning lumbar interbody fusion than non-smokers in a clinical comparative setting. METHODS Spondylodesis outcomes in 50 patients, 34 non-smokers (mean 58 years; (range 29-81) and 16 smokers (mean 47 years; range 29-75) were compared preoperatively and one year after spondylodesis surgery using Oswestry-Disability-Index (ODI), visual analogue scale (VAS) and radiological outcome analysis of fusion-success. RESULTS Smokers showed a comparable ODI-improvement (p = 0.9343) and pain reduction to non-smokers (p = 0.5451). The intake of opioids was only reduced in non-smokers one year after surgery. Fusion success was significantly better in non-smokers (p = 0.01). CONCLUSIONS The results indicate that smoking adversely effects spinal fusion. Particularly re-operations caused by pseudarthrosis occur at a higher rate in smokers than in non-smokers.

Temperature distribution during radiofrequency ablation of spinal metastases in a human cadaver model: Comparison of three electrodes

BACKGROUND Radiofrequency ablation (RFA) temperatures reaching 45°C in adjacent tissues are cytotoxic to the spinal cord, nerves and surrounding tissues. OBJECTIVE This study compares different RFA electrodes with regard to the temperature distribution during ablation of spinal metastases. METHODS In vitro experimental study in isolated lumbar vertebrae of a human cadaveric spine. The temperature distribution of RFA electrodes was measured during ablation in human cadaveric lumbar vertebrae containing a simulated vertebral body lesion. The analysis compared a novel bipolar RFA electrode with two conventional monopolar RFA electrodes. A vertebral metastasis model was prepared in eight lumbar vertebrae for each electrode. Differences between the electrodes were evaluated with a one-way ANOVA. RESULTS The lowest temperature at the thermocouples adjacent to the simulated lesion was achieved when using the bipolar RFA electrode (46.4 ± 3.3°C), but temperature difference to the monopolar RFA electrodes was not significant. In the neural foramen and epidural space of lumbar vertebrae the maximal temperature measured when using the bipolar RFA electrode was 37.0 ± 0°C and 37.3 ± 0.7°C, which was significantly lower than during ablation via either of the monopolar RFA electrodes (p ≤ 0.001). CONCLUSIONS Temperatures in areas of adjacent tissue during RFA using a specific for spinal ablation designed electrode with integrated thermocouples were significantly lower compared to other electrodes, potentially reducing temperature related risks during ablation.

Mid-term results after implantation of rotating-hinge knee prostheses: primary versus revision

The aim of the study was to evaluate the mid-term clinical results and survivorship of a rotating-hinge knee prosthesis (LINK® Endo-Model) in difficult primary and complex revision situations. Results after primary implantation were compared with those of revision procedures. Forty-nine prostheses in 45 patients were reviewed clinically during follow up. Twenty-one of these were implanted in primary and 28 in revision situations. Outcome was evaluated using commonly used scores (Knee Society, UCLA Activity, Lequesne) and a visual analog scale after a mean follow up of 56±37 months for 49 prostheses. Implant survival was analyzed using the Kaplan-Meier method. There were no significant differences in clinical examination and evaluation scores between the two groups (P>0.05). Survival rates at final follow up were 95% after primary implantation and 76% in revision procedures. The risk of prosthesis loss (odds ratio 5.7) was significantly higher after revision procedures (P=0.004). These data suggest that rotating-hinge knee prostheses provided good clinical and functional results in selected cases of advanced primary gonarthrosis associated with severe bone loss, ligamentous instability or comminuted fractures. They also provide good results in revision situations. However, the failure rate was significantly higher in cases of revision surgery.

Extracorporeal shock wave therapy for non-calcific supraspinatus tendinitis – 10-year follow-up of a randomized placebo-controlled trial

Abstract Evidence for the efficacy of extracorporeal shock wave therapy (ESWT) in supraspinatus tendinopathy without calcification is sparse, and therefore this treatment option is often controversial. Patients of a randomized placebo-controlled study to analyze the effects of ESWT on function and pain were revisited 10 years after the initial consultation. The former verum group received 6000 impulses (energy flux density, 0.11 mJ/mm2) in three sessions after local anesthesia between 1999 and 2000. The placebo group had 6000 impulses of a sham ESWT after local anesthesia in the same period. Re-evaluation of the patients included a relative Constant score as well as pain measurements (visual analogue scale) during activity and at rest. No significant changes (p>0.05) in relative Constant scores, pain at rest, or pain during activity could be found after a 10-year follow-up between the placebo and verum groups after ESWT. The treatment of non-calcific supraspinatus tendinopathy with ESWT does not seem to have an effect on function or pain improvement in the long run. The results of the present study cannot advise the use of ESWT in cases of non-calcific supraspinatus tendinopathy.

Two-year clinical results of patients with sacroiliac joint syndrome treated by arthrodesis using a triangular implant system

BACKGROUND Sacroiliac joint (SIJ) syndrome can cause various symptoms and may also be one reason for persistent low back pain, especially in patients with prior spinal fusions. If conservative treatments fail to improve symptoms, arthrodesis surgery can be considered. Minimally invasive approaches have emerged recently providing a good alternative to conventional methods. A novel triangular implant system (iFuse) can achieve an arthrodesis of the SIJ without the use of additional screws or bone material. OBJECTIVE Aim of the present study was an evaluation of short-term safety and efficacy of the implant system. METHODS Twenty-four patients were included in the study and treated with the iFuse system. In addition to demographic data, pain intensity (visual analogue scale) and functional impairment (Oswestry-disability index) were assessed prior to surgery and 1 month, 3 months, 6 months, 12 months and 24 months thereafter. During surgery and the follow up period all adverse events were documented and the correct implant position was controlled via plain radiographs. RESULTS VAS scores and ODI improved significantly directly after surgery from 84.3 ± 9.2 mm to 40.7 ± 9.2 mm and from 76.8 ± 9.2% to 40.7 ± 9.2 % (p < 0.001). The ODI improved further to 31 ± 5.4% after 24 months whereas the VAS improved until the 3 months examination and ten stayed constant between 27.7 mm and 26.5 mm to 27 ± 6.6 mm at 24 months. No adverse events, intraoperative complications, implant malpositioning or loosening could be recorded at any time. CONCLUSIONS The iFuse system is an effective and safe treatment for minimally invasive surgical arthrodesis of the SIJ. Pain and functional impairment can be significantly improved. However, in addition to this case series, further controlled studies are necessary, particularly in terms of a previous spinal fusion history.

Anatomic dissection of the anterolateral ligament (ALL) in paired fresh-frozen cadaveric knee joints

IntroductionDifferent dissection studies as well as comparative studies about the anterolateral ligament of the knee (ALL) already exist and the structure’s topology and properties have been shown. However, most of the studies investigating the ligament were performed in embalmed knees, which is thought to change the structural integrity of ligaments and thus the topologic and dynamic measurements. Since the biomechanical function of the ALL is not fully understood until today and a correlation with the pivot shift phenomenon is yet speculative, further studies will have to clarify its definitive importance. Its function as a limiter of internal rotation and lateral meniscal extrusion leads to the assumption of a secondary knee stabilizer.MethodsTwenty paired fresh-frozen cadaveric knees of ten donors have been dissected in a layerwise fashion. After identification of the ALL, topologic measurements were undertaken using a digital caliper.ResultsThe ALL could be identified as a tender, pearly structure in front of the anterolateral joint capsule in only 60% of the dissected knee joints. Only 20% of donors had a bilateral ALL while 80% had an ALL only in one side. Mean length, thickness and width as well as topographic measurements were comparable to other available studies investigating fresh-frozen cadavers.ConclusionAnatomy and topography of the ALL seem to be highly variable, but consistent within certain borders. Prevalence has to be argued though as it strongly differs between studies. The impact of an ALL absence, even if only unilateral, needs to be investigated in clinical and imaging studies to finally clarify its importance.

The QuickLine IL-6 lateral flow immunoassay improves the rapid intraoperative diagnosis of suspected periprosthetic joint infections.

BACKGROUND When deciding upon the best treatment strategy in revision arthroplasty, it is absolutely crucial to use the best possible preoperative detection whether a periprosthetic joint infection (PJI) is present or not. New molecular markers investigated in serum samples and synovial fluid can help to improve the preoperative diagnosis. In 2001, a novel IL-6 lateral flow immunoassay testing device was introduced which has never been tested in synovial fluid so far. OBJECTIVE For our study we investigated whether the test can be used safely, feasibly and time effectively with synovial fluid gathered from potentially infected THAs or TKAs and whether the already published cutoff for IL-6 in synovial fluid predicting a PJI can be reproduced using the QuickLine IL-6 immunoassay. METHODS After ethic approval and within the scope of a prospective controlled trial we investigated 26 patients (m = 9, 34.6%; f= 17, 65.4%) with n = 13 (50%) potentially infected total hip arthroplasties (THAs) and n = 13 (50%) suspected PJIs of total knee arthroplasties (TKAs). Sterile aspirated synovial fluid was examined for total leukocyte count and cell differentiation by a blood count analyzer in body fluid mode as well as for IL-6 (Immulite, Siemens Medical Solutions Diagnostics GmbH, Eschborn, Germany). Another part of the joint aspirate was tested using the QuickLine IL-6 Test by Milenia Biotec (Milenia Biotec, Gießen, Germany). RESULTS The mean concentration of IL-6 as determined from our reference laboratory testing (Siemens Immulight) for aseptic cases was 1,219 pg/mL (SD 1,369 pg/mL, min 134 pg/mL-max 4,214 pg/mL). The mean IL-6 concentration measured via the IL-6 QuickLine for aseptic cases was 410 pg/mL (SD 371 pg/mL, min 100 pg/mL-max 1562 pg/mL). The test showed no false negative or false positive results in the cases tested. In six patients, PJI was considered proven. The QuickLine Test indicated IL 6 concentrations > 10,000 pg/mL in these cases without further quantification above this maximum detection threshold. Results from the QuickLine Test and the laboratory tests were matched and a non-linear best fit curve (log-log-curve) was applied. The subsequent Spearman correlation showed a correlation coefficient of r = 0.92 (95% CI 0.81-0.97) which corresponds to a two-tailed p-value of < 0.0001, respectively. As a primary finding we were able to show that the Milenia QuickLine IL-6 Test can be used safely, feasibly and time effectively with synovial fluid gathered intraoperatively from potentially infected THAs or TKAs. The test as provided worked well in 84.6% of the samples tested and failed only due to very viscous synovial fluid. As a secondary result we found that the previously published cut-off for IL-6 in synovial fluid predicting a PJI with a sensitivity of 46.88% and a specificity of 97.62% can be reproduced using the QuickLine IL-6 immunoassay. CONCLUSION Taking the limitations of the low sample size as a given this relatively simple point of care (POC) assay showed promising results in our pilot trial and may help diagnosing PJI. It may help physicians and surgeons to choose the best and least invasive treatment strategy for patients presenting with painful arthroplasty.