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Hermann Anetzberger,1 Christof Birkenmaier,2 Stephan Lorenz3 1Orthopädische Gemeinschaftspraxis am OEZ, Munich, Germany; 2Department of Orthopedics, Ludwig-Maximilian-University Munich, Munich, Germany; 3Department of Orthopedic Sports Medicine, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany Abstract: Meniscal injuries are among the most frequent reasons for knee problems. The goal of this manuscript is to review the biomechanical relevance of the human knee's menisci in relation to surgical indications, surgical techniques, rehabilitation, and outcomes. In order to identify the relevant literature, we performed a PubMed search for the years ranging from 1980–2013 using the following search terms: meniscus; biomechanical function; meniscectomy; meniscal repair; and clinical outcome. The meniscus helps to distribute the forces between the tibial and femoral articular cartilage layers in a load-sharing capacity. Meniscus damage or meniscectomy intuitively leads to an overloading of the cartilage and, hence, to the development of osteoarthrosis. Precise knowledge of meniscal shape and function, of the type of injury, of surgical techniques, as well as of postsurgical rehabilitative care are of decisive importance for an individually-adjusted treatment strategy. Other underlying coexisting knee pathologies also need to be considered. The diagnosis of a meniscal injury is based upon clinical history, physical examination, and imaging studies. The treatment of a meniscal lesion includes conservative, as well as operative, procedures. The goals of surgery are to reduce pain and disability, as well as to preserve meniscal function without causing additional cartilage damage. The resection of meniscal tissue should be restricted to as much as is necessary, and as little as is reasonably possible. Postoperative rehabilitation serves the purpose of improving functional deficits and pain, as well as of restoring a good range of motion and preventing secondary damage. It is the surgical therapy that dictates the aftercare, and with regards to the latter, there are clear differences between meniscectomy and meniscal repair. Keywords: meniscectomy, osteoarthritis, meniscus pathology, meniscus function

In revision hip arthroplasty with bone defects of the proximal femur, a well-established treatment method is reconstruction with impacted allograft spongiosa chips and cemented implantation of a polished stem. Building on this principle of impacted bone grafting, a femoral implant, which is suited to uncemented hip arthroplasty as well as for uncemented revisions, was designed. This so-called compression-rotation stem (CR stem) is collarless and has flanks which compress the impacted bone chips during implantation and thereby increase the rotational stability. To evaluate the primary stability of this new shaft after impaction grafting, the micromotion was determined using six motion transducers. Under physiological loading conditions with simulation of the muscle activities at the proximal femur the application was dynamically loaded for 15,000 cycles with 1000 +/- 500 N and afterwards for 5000 cycles with 1300 +/- 1000 N. Uncemented CR stems and the control Exeter stems were implanted in a standardized manner according to the X-Change method. Therefore they were implanted into artificial femora that had been previously resected, hollowed, and filled with impacted human spongeous bone allograft to simulate bone defects. Subsequently, the femora were loaded under identical conditions and the micromotions measured. In the majority of the implantations, no significant differences could be found. In conclusion, similar clinical results for the two stems should be expected. [ABSTRACT FROM AUTHOR]

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Purpose: In the last 15 years, vertebroplasty and kyphoplasty have become established operative procedures for treating osteoporotic vertebral-body fractures and vertebral bodies afflicted with metastases. These procedures are quickly performed with few personnel and material resources and have a low rate of complications. However, cases of neurological impairment are reported in the scientific literature. We analysed whether potentially harmful heat is radiated/conducted by the polymerisation temperature of polymethylmethacrylate (PMMA) bone cement in the spinal canal.Methods: We performed vertebroplasty on 25 vertebral bodies and measured the temperature distribution during polymerisation of bone cement within the spinal canal using heat probes placed in the respective areas. The vertebral bodies were located in a circulating water bath at 37°C.Results: During polymerisation of the bone cement, a temperature rise was measured. The peak temperature was reached after few minutes. Temperature curves differed; a maximum temperature of up to 43.16°C was detected for a few seconds only.Conclusion: When vertebroplasty is performed correctly, there is no temperature development that could eventually damage the spinal cord or spinal nerves. [ABSTRACT FROM AUTHOR]

There is growing evidence that platelets play an important role in the development and maintenance of rheumatoid arthritis. Activation and adherence of platelets in the synovial microcirculation might be in part responsible for endothelial damage and activation of leukocytes. Recent findings show a direct influence of P-selectin on platelet- and leukocyte-endothelial cell interaction in mice with Antigen-induced Arthritis (AiA). P-selectin is only expressed by platelets and endothelial cells, not by leukocytes. Therefore, the aim of the present study was to investigate the differential influence of platelet and endothelial P-selectin on the extent of inflammation in AiA. AiA was induced in wild-type mice and in P-selectin-deficient mice from the same genetic background (four groups: each n = 7). Intravital fluorescence microscopy (IVM) was used to visualize platelets and leukocytes in the synovial microcirculation at day 8 after AiA. Platelets from either strain were fluorescence-labelled ex vivo and transferred into either strain. We were able to demonstrate a significant decrease of platelet- and leukocyte-endothelial cell interaction in P-selectin-deficient mice with AiA in comparison to wild-type mice with AiA. When wild-type platelets were donated into P-selectin-deficient AiA recipients, the leukocyte-endothelial cell interaction was significantly increased compared to the group consisting of P-selectin-deficient recipient and donor mice. These are the first in vivo results showing that the P-selectin stored in platelets is at least partly responsible for the leukocyte-endothelial cell interaction and the resulting tissue damage in AiA. In the future, a suppression of platelet P-selectin could potentially become a treatment option for reducing the effects of rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

Background and Objectives: At many institutions, it is not practically feasible to perform a series of controlled or placebo-controlled medial branch blocks on several facet joints in order to select patients for facet joint rhizotomy. As for uncontrolled blocks, there is no proof that medial branch blocks are superior to other types of blocks. This study was performed to compare medial branch blocks to simple pericapsular blocks for the selection of patients for lumbar facet joint cryodenervation.Methods: Patient selection was based on history, imaging, and physical examination. Diagnostic blocks were either medial branch blocks or pericapsular blocks. Percutaneous medial branch cryodenervation was performed by use of a Lloyd Neurostat 2000. Outcome parameters were low back pain (visual analog scale [VAS]), limitation of activity (Macnab), and overall satisfaction. A total of 26 patients were recruited, 13 for each group. Follow-up was 6 months.Results: Patients who had been selected by medial branch blocks had better pain relief than did patients who had been diagnosed by use of pericapsular blocks. At 6 weeks and at 3 months after treatment, these results reached statistical significance (VAS 2.2 v 4.2, P < .05).Conclusions: Our results suggest that uncontrolled medial branch blocks are superior to pericapsular blocks in selecting patients for facet joint cryodenervation, but both blocks work. If serial controlled blocks cannot be used, lumbar facet joint pain remains a diagnostic dilemma. [ABSTRACT FROM AUTHOR]

We present the case of an otherwise healthy female hairdresser of Brazilian origin who started to have pain and swelling in her left arm. An antecubital abscess was surgically treated at another institution and there was good initial wound healing. Swelling then recurred and fistulae appeared in the scar. Our diagnostic workup revealed an isolated intramuscular tuberculous abscess, which was successfully treated by an antituberculous drug regimen. [ABSTRACT FROM AUTHOR]

Abstract Background Because of the implant-related problems with pedicle screw-based spinal instrumentations, other types of fixation have been tried in spinal arthrodesis. One such technique is the direct trans-pedicular, trans-discal screw fixation, pioneered by Grob for spondylolisthesis. The newly developed GO-LIF procedure expands the scope of the Grob technique in several important ways and adds security by means of robotic-assisted navigation. This is the first clinical trial on the GO-LIF procedure and it will assess safety and efficacy. Methods/Design Multicentric prospective study with n = 40 patients to undergo single level instrumented spinal arthrodesis of the lumbar or the lumbosacral spine, based on a diagnosis of: painful disc degeneration, painful erosive osteochondrosis, segmental instability, recurrent disc herniation, spinal canal stenosis or foraminal stenosis. The primary target criteria with regards to safety are: The number, severity and cause of intra- and perioperative complications. The number of significant penetrations of the cortical layer of the vertebral body by the implant as recognized on postoperative CT. The primary target parameters with regards to feasibility are: Performance of the procedure according to the preoperative plan. The planned follow-up is 12 months and the following scores will be evaluated as secondary target parameters with regards to clinical improvement: VAS back pain, VAS leg pain, Oswestry Disability Index, short form - 12 health questionnaire and the Swiss spinal stenosis questionnaire for patients with spinal claudication. The secondary parameters with regards to construct stability are visible fusion or lack thereof and signs of implant loosening, implant migration or pseudarthrosis on plain and functional radiographs. Discussion This trial will for the first time assess the safety and efficacy of guided oblique lumbar interbody fusion. There is no control group, but the results, the outcome and the rate of any complications will be analyzed on the background of the literature on instrumented spinal fusion. Despite its limitations, we expect that this study will serve as the key step in deciding whether a direct comparative trial with another fusion technique is warranted. Trial Registration Clinical Trials NCT00810433

While no gold standard exists for the management of Achilles tendon ruptures, surgical repair is common in healthy and active patients. Minimally invasive repair methods have become increasingly popular, while biomechanical equivalency hasn't been proven yet. A mid-substance Achilles tendon rupture was created 6 cm proximal to the calcaneal insertion in 27 fresh-frozen cadaveric ankles. Specimens were randomly allocated to 1 of 3 repair techniques: Huttunen et al. (2014) (1) PARS Achilles Jig System, Nyyssönen et al. (2008) (2) Achilles Midsubstance SpeedBridge™, Schipper and Cohen (2017) (3) Dresdner Instrument and subsequently subjected to cyclic loading with 250 cycles each at 1 Hz with 4 different loading ranges (20–100 N, 20–200 N, 20–300 N, and 20–400 N). After 250 cycles no significant differences in elongation were observed between PARS and Dresdner Instrument(p = 1.0). Furthermore, SpeedBridge™ repairs elongated less than either Dresdner Instrument (p = 0.0006) or PARS (p = 0.102). Main elongation (85%) occurred within the first 10 cycles with a comparable elongation in between 10 and 100 and 100–250 cycles. While all repairs withstood the first 250 cycles of cyclic loading from 20 to 100 N, only the PARS (468 ± 175) and Midsubstance SpeedBridge™ (538 ± 208) survived more cycles. Within all 3 groups suture cut out was seen to be the most common failure mechanism. Within all groups early repair elongation was seen. While this was least obvious within the SpeedBridge™ technique, ultimate strengths of repairs (cycles to failure) were comparable across PARS and SpeedBridge™ with a decline in the Dresdner Instrument group. • All repairs survived the first 250 cycles, while none survived all 4 loading stages. • Dresdner Instrument repair completed significantly less cycles prior to failure. • Suture cutout at the suture-tendon interface was the primary failure mechanism. • The model presents a simplified representation of the biomechanical characteristics. [ABSTRACT FROM AUTHOR]