Neoadjuvant Therapy and Axillary Lymph Node Status in HER2-Positive Breast Cancer.

Based on an estimating model, the aim of our study was to evaluate the axillary lymph node involvement of patients with primary invasive early human epidermal growth factor receptor 2 (HER2)-positive breast cancer before receiving neoadjuvant therapy (NAT). Patients with primary surgery (n = 63) were compared with patients who had received NAT (combined chemo/HER2-targeted antibody therapy) before surgery (n = 152). In patients receiving NAT, a positive N stage was estimated in 73.2 (49.8%) tumors resulting in a conversion (positive N stage-ypNpositive) of 35.5%. In 126 cases with ypN0 stage, a positive N stage was estimated in 41.4%.

Infraspinatus shift for massive, posterosuperior tears yields good clinical outcome.

AIM: To evaluate the functional outcome of partial reconstruction margin convergence in the treatment of massive, irreparable posterosuperior rotator cuff tear (RCT). METHODS: This retrospective, single-center study included all patients that were operated by means of a partial repair and infraspinatus shift for a massive, posterosuperior cuff tear between 2009 and 2016, either in arthroscopic or mini-open technique. Outcome measures included sex- and age-adapted Constant Score (saCS), Western Ontario Rotator Cuff (WORC) Index, Disabilities of Arm, Shoulder and Hand Scores (DASH), and relative effect per patient (REPP). RESULTS: Fifty-six shoulders in 54 patients (mean age: 66 ± 7 years) were evaluated at a mean follow-up of 40 ± 9 months. The mean tear size was Bateman 3.1 ± 0.7 and Patte 2.3 ± 0.4. All clinical scores showed improvement. The saCS improved from 64.1 ± 13.4 to 90.4 ± 13.7 (p < 0.0001), the DASH score from 51.8 ± 9.4 to 10.2 ± 13.4 (p < 0.0001) and the WORC index from 47.1% ± 8.6 to 87.9% ± 13.7 (p < 0.0001). The abduction strength of the affected side (1.7 ± 1.6 kg) was not restored to the same level as the contralateral side (5.4 ± 2.7 kg, p < 0.0001). CONCLUSION: Partial cuff repair for posterosuperior, massive cuff tears yields good clinical outcome with a low rate of complications and high proportion of good and excellent responders. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

High injury rates and weak injury prevention strategies in football referees at all levels of play.

Football referees need other physiological requirements on field than football players and are affected by different types of injury. The absence of referees may result in canceled matches, so special focus should be placed on injury prevention through specific training programs for referees. This study retrospectively analyzed injury occurrence and prevention strategies for German football referees at the different levels of play over one season. Data were collected by means of seasonal injury reports based on the consensus statement of injury definition and data collection. Of the 923 participating referees, 91 (9.9%) played at the professional level, 151 (16.3%) at the semi-professional, and 681 (73.8%) at the amateur level. 86.2% (n = 796) were men and 13.8% (n = 127) women. Referees at the amateur level showed the highest injury incidence (3.14/1000 h football) compared to referees at the semi-professional (1.92/1000 h; p < 0.001) and professional level (1.01/1000 h; p < 0.001). Most referees at the amateur (n = 372; 56.4%) and semi-professional level (n = 46; 31.3%) conducted warm-up programs of <10 min, whereas the mean warm-up duration of professional referees was >11 min (n = 75; 82.4%). Although running and stretching exercises were common among referees during warm-up, preventive exercises focusing on coordination and trunk muscles were less frequent, especially among amateur referees (jumping: 15.9%; strengthening: 9.7%; balance exercises: 7.9%). Injury incidence was highest at lower amateur levels, which thus has specific need for injury prevention. Appropriate training exercises to prevent injuries of referees were weak at all levels of play, especially the lack of strength, plyometric, and balance exercises in training and warm-up programs.

Higher risk of ACL rupture in amateur football compared to professional football: 5-year results of the 'Anterior cruciate ligament-registry in German football'.

PURPOSE: Anterior cruciate ligament (ACL) injuries are a common severe type of football injury at all levels of play. A football-specific ACL registry providing both prospective ACL injury data according to the skill level and risk factors for ACL injury is lacking in the literature. METHODS: This study is based on the prospective 'ACL registry in German Football' implemented in the 2014-15 season. Professional (1st-3rd league), semi-professional (4th-6th league) and amateur leagues (7th league) were analysed regarding the incidence and risk factors for ACL injuries. Injuries were registered according to the direct reports of the injured players to the study office and double-checked via media analysis. After injury registration, the players received a standardised questionnaire. Data were analysed from the 2014-15 to the 2018-19 football season. RESULTS: Overall, 958 ACL injuries were registered during the 5-year study period. The incidence of ACL injuries was highest in amateur football (0.074/1000 h football exposure) compared to professional (0.058/1000 h; p < 0.0001) and semi-professional football (0.043/1000 h; p < 0.0001). At all skill levels, match incidence (professional: 0.343; semi-professional: 0.249; amateur: 0.319) was significantly higher than training incidence (professional: 0.015; semi-professional: 0.004; amateur: 0.005). Major risk factors were previous ACL injury (mean: 23.3%), other knee injuries (mean: 19.3%) and move to a higher league (mean: 24.2%). CONCLUSION: This sports-specific ACL registry provides detailed information on the incidence and risk factors for ACL injuries in football over five years. Risk factors are skill level, match exposure, move to a higher league and previous knee injury. These factors offer potential starting points for screening at-risk players and applying targeted prevention. LEVEL OF EVIDENCE: II.

Epidemiological analysis of injury occurrence and current prevention strategies on international amateur football level during the UEFA Regions Cup 2019.

INTRODUCTION: Football is the most popular sport worldwide and results in a high frequency of injuries. So far, mainly injuries in professional football have been investigated, and the literature lacks data regarding detailed injury epidemiology and current prevention data in amateur football tournaments. MATERIALS AND METHODS: A prospective cohort study investigated an international amateur football tournament, the UEFA Regions' Cup, which took place in 2019 in Germany. Injury epidemiology, current prevention strategies of the teams and the implementation of the UEFA concussion protocol were investigated in detail by means of standardized injury definitions and data samples for football (Fuller et al., Scand J Med Sci Sports 16:83-92, https://doi.org/10.1111/j.1600-0838.2006.00528.x , 2006). RESULTS: 138 player of 8 teams participated in this study, while 39 players were excluded. Overall injury incidence was 12.5 per 1000 h total football exposure, 43.5 per 1000 h for match exposure. No injuries were registered during training. Injury prevalence was 14.1% per player and 1.1 injuries per match were registered. The lower extremity was predominantly affected by injuries (71.4%) and the majority of injuries (78.6%) were non-severe injury types like contusions (50%) and sprains (18.2%). Two head injuries, one contusion and one skin lesion, were handled by the guidelines of the UEFA concussion protocol. 44.4% of the players indicated at least one previous injury before tournament, 45.3% of them during the last two football seasons before start of the tournament. Injury prevention performance was included in all participating teams during the tournament by warm up or training strategies (100%). During the warm-up program just 5 exercises of the FIFA 11 + program was detected by this investigation in participating teams to be done by more half of the teams. Running exercises were the most frequently performed exercises, while trunk muscle exercises were less represented (14.3%). CONCLUSION: This study presents for the first time epidemiological injury and prevention data of the UEFA Regions Cup. Injury incidence was higher compared to injury reports of regular seasons, but lower compared to other amateur football tournaments. Currently used prevention programs revealed trunk muscle exercises as often neglected.

Practical Relevance of Institutional Guidelines in Translational Large Animal Studies of Cartilage Repair-A Multidisciplinary Survey.

Background and Objective: Translational large animal models are inevitable to transfer cartilage repair methods into clinical practice. Guidelines for these trials have been published by guiding agencies (FDA, ASTM, EMEA) including recommendations for study descriptors and study outcomes. However, practical adherence to these recommendations is not achieved in all aspects. This study includes an assessment of the recommended aspects regarding practical relevance in large animal models for cartilage repair by professionals in the field. Materials and Methods: In an online based survey, 11 aspects regarding study design and 13 aspects regarding study outcome from previously published guidelines were evaluated (0-10 points, with 10 being most important) by study participants. Additionally, the survey contained questions related to professional experience (years), professional focus (preclinical, clinical, veterinarian, industry) and the preferred translational large animal model for cartilage repair. Results: The total number of survey participants was 37. Rated as most important for study design parameters was lesion size (9.54 pts., SD 0.80) followed by study duration (9.43 pts., SD 1.21); and method of scaffold fixation (9.08 pts., SD 1.30) as well as depth of the lesion (9.03 pts., SD 1.77). The most important aspects of study outcome were considered histology (9.41 pts., SD 0.86) and defect filling (8.97 pts., SD 1.21), while gene expression was judged as the least important (6.11 pts., SD 2.46) outcome. A total of 62.2% of all participants were researchers, 18.9% clinicians, 13.5% veterinarians and 5.4% industry employees. Conclusions: In translational research, recommendations published by guiding agencies receive broad theoretical consensus within the community, including both clinically and preclinically orientated scientists. However, implementation into practical research lacks in major aspects. Ongoing re-evaluation of the guidelines under involvement of all stakeholders and approaches to overcome financial and infrastructural limitations could support the acceptance of the guidance documents and contribute to standardization in the field.

"Anemia and Response to Neoadjuvant Chemotherapy in Breast Cancer Patients".

We analyzed the effect of anemia on tumor response of patients with primary invasive breast cancer (BC) receiving neoadjuvant chemotherapy (NACT). The patient collective was very homogenous; finally, 74 BC patients with identical medication and duration of NACT were enrolled. After completion of NACT, 49 patients (66.2%) had a post-NACT Hb level <12 g/dl. In the anemic group, we found a tendency of lower median tumor response compared to nonanemic patients at this time (15 versus 17 mm, retrospectively, p = 0.18). Age at diagnosis significantly correlated with the difference of Hb [before initiation - after completion of NACT] (correlation coefficient = 0.40, p < 0.001).

Post-operative septic arthritis after arthroscopy: modern diagnostic and therapeutic concepts.

PURPOSE: Septic arthritis is a significant complication following arthroscopic surgery, with an estimated overall incidence of less than 1%. Despite the low incidence, an appropriate diagnostic and therapeutic pathway is required to avoid serious long-term consequences, eradicate the infection, and ensure good treatment outcomes. The aim of this current review article is to summarize evidence-based literature regarding diagnostic and therapeutic options of post-operative septic arthritis after arthroscopy. METHODS: Through a literature review, up-to-date treatment algorithms and therapies have been identified. Additionally, a supportive new algorithm is proposed for diagnosis and treatment of suspected septic arthritis following arthroscopic intervention. RESULTS: A major challenge in diagnostics is the differentiation of the post-operative status between a non-infected hyperinflammatory joint versus septic arthritis, due to clinical symptoms, (e.g., rubor, calor, or tumor) can appear identical. Therefore, joint puncture for microbiological evaluation, especially for fast leukocyte cell-count diagnostics, is advocated. A cell count of more than 20.000 leukocyte/µl with more than 70% of polymorphonuclear cells is the generally accepted threshold for septic arthritis. CONCLUSION: The therapy is based on arthroscopic or open surgical debridement for synovectomy and irrigation of the joint, in combination with an adequate antibiotic therapy for 6-12 weeks. Removal of indwelling hardware, such as interference screws for ACL repair or anchors for rotator cuff repair, is recommended in chronic cases. LEVEL OF EVIDENCE: IV.

Reversed shoulder arthroplasty leads to significant histological changes of the deltoid muscle: a prospective intervention trial.

INTRODUCTION: Reverse shoulder arthroplasty (RSA) shows promising short- and mid-term results in cuff tear arthropathy. However, functional impairments are described in long-term findings. Micromorphological changes in the periarticular musculature could be in part responsible for this, but have not yet been analysed. Thus, histological changes of the deltoid muscle and their association to the functional outcome were evaluated in this study. MATERIAL AND METHODS: A total of 15 patients treated with RSA were included in this prospective study. Functional outcome was assessed using the Constant Score (CS) and the DASH (disabilities of the arm, shoulder and hand) Score before RSA and after a mean follow-up of 12 months. Deltoid muscle biopsies were harvested intraoperatively and 12 months postoperatively. Mean deltoid muscle fibre area (MMFA) was calculated histologically after haematoxylin-eosin staining. RESULTS: Postoperative shoulder function significantly improved within 12 months (CS: Δ 37.4 ± 22.6, p = 0.001; DASH: Δ 27.1 ± 29.1, p = 0.006). The MMFA significantly decreased (p = 0.02), comparing the results from the intraoperative biopsy (MMFA: 8435.8 µm2, SD ± 5995.9 µm2) to the 12 months biopsy (MMFA: 5792. µm2, SD ± 3223.6 µm2). No correlation could be found between the functional score results and MMFA. CONCLUSION: Signs of deltoid muscle changes in terms of a reduced MMFA can be detected 1 year after RSA and thus already a long time before long-term functional impairments become apparent. Further studies with larger patient series and longer follow-up periods as well as extended histological assessments and simultaneous radiological examinations are required.

[Comparison of DRG revenues between fast and slow-track procedures for a two-stage replacement of prostheses for periprosthetic hip infections in the aG-DRG system 2020]. / Vergleich der DRG-Erlöse zwischen Fast- und Slow-Track-Verfahren beim zweizeitigen Prothesenwechsel bei periprothetischen Hüftinfektionen im aG-DRG-System 2020.

BACKGROUND: The treatment of periprosthetic hip infections is usually cost intensive, so it is generally not cost effective for hospitals. In chronic infections, a two-stage procedure is often indicated, which can be done as a fast-track procedure with a short prosthetic-free interim interval (2-4 weeks) or as a slow-track procedure with a long prosthetic-free interim interval (over 4 weeks). AIM: The aim of this study was to elucidate the revenue situation of both forms of treatment in the aG-DRG-System 2020, taking into account revenue-relevant influencing factors. METHODS: For fast-track and slow-track procedures with two-stage revision and detection of a staphylococcus aureus (MSSA), treatment cases were simulated using a grouper software (3M KODIP Suite) based on the diagnoses (ICD-10-GM) and procedures (OPS) and then grouped into DRGs. Revenue-relevant parameters, such as length of stay and secondary diagnoses (SD), were taken into account. In addition, two real treatment cases with fast-track and slow-track procedures were compared to each other. RESULTS: The total revenues for the slow-track procedure with a length of stay of 25 days (without SD) were 27,551 € and for a length of stay of 42 days (with SD) even 40,699 €, compared to 23,965 € with the fast-track procedure with a length of stay of 25 days (without SD) and 27,283 € for a length of stay of 42 days (with SD). The real treatment cases also showed a big difference in the total revenues of 12,244 € in favor of the slow-track procedure. DISCUSSION: Even in the aG-DRG-System 2020, the two-stage revision procedure with a long interim interval seems to be more interesting from a financial point of view and the hospital perspective compared to the fast-track procedure, especially with multimorbid patients. This creates a financial barrier to the treatment of such patients with a short interim interval.

[Analysis of injury incidences in a trauma surgery university hospital during the SARS-CoV­2 pandemic]. / Analyse des Trauma-Aufkommens in einer unfallchirurgischen Universitätsklinik während der SARS-CoV­2-Pandemie.

INTRODUCTION: The corona crisis of 2020 posed previously unknown challenges to hospitals providing acute care. In addition to the treatment of COVID-19 patients, universities and other acute care hospitals had to provide emergency medical care, including for patients undergoing trauma surgery. The challenge was that no reliable planning figures were available regarding the expected volume for such a crisis situation and therefore no reliable resource planning was possible in this respect. Therefore, the aim of this work was to record the incidence of polytrauma and other injuries during the pandemic crisis in a university trauma surgery clinic and to compare it with the years 2017-2019. METHODS: In this single-center study, a retrospective analysis of the injury incidence during calendar weeks with existing exit restrictions (12th-19th week) for the year 2020 for trauma surgery patients of a university hospital was performed. At first, the treatment of COVID-19 patients was recorded daily in order to objectify the burden and expenditure of inpatient treatment for these patients. Then, for the evaluation period from 20.03.2020 to 06.05.2020, the numbers of 1. polytrauma, 2. work-related accidents and 3. leisure-related trauma patients were recorded and compared with the numbers from 2017-2019 during the same period. RESULTS: In total, 118 patients were treated with COVID-19 as inpatients during the period under study, of which up to 43 patients had to be treated simultaneously in intensive care on 1 day. Overall, the number of polytrauma, work-related accidents and leisure-time accident patients was lower in 2020 than in the previous years. Nevertheless, with a decline of only -28% (22 ± 4.9 vs. 16), a considerable number of polytrauma patients were recorded, while all work-related accidents (44%, 304 ± 31.3 vs. 170) and also leisure-time accidents (39%, 173 ± 22.7 vs. 106) considerably decreased. In the group of leisure-time accidents, there was initially a remarkable decline in the number of cases per week after the initial restrictions began, but as the duration of the restrictions increased, the number per week has risen to the level of previous years. DISCUSSION: Even in exceptional situations such as the corona pandemic, there were a significant number of patients in need of acute treatment, especially polytrauma patients. This should be considered in the future in the event of similar exceptional situations in the inpatient care framework when providing trauma surgery care capacities.

Patient-reported outcome after patient-specific unicondylar knee arthroplasty for unicompartmental knee osteoarthritis.

BACKGROUND: Unicondylar knee arthroplasty was introduced in the late 1960s and remains a topic of controversial discussion. Patient-specific instruments and patient-specific implants are not yet the standard of care. The question remains whether this time-consuming and costly technique can be beneficial for the patient. The aim of this study was to evaluate whether a custom-made unicondylar knee arthroplasty leads to improved patient-reported outcome. METHODS: This retrospective study evaluates the patient-reported outcome after custom-made unicondylar knee arthroplasty (CM-UKA, ConforMIS™ iUni® G2, ConforMIS Inc., Billerica, MA, USA). We evaluated 29 patients (31 knees) at an average of 2.4 years (range 1.2-3.6 years) after operation for unicondylar osteoarthritis of the knee. The target zone for the postoperative leg axis was a slight under-correction of 0-2° varus. Follow-up evaluation included the Forgotten Joint Score (FJS), the Knee Society Score (KSS), a Visual Analogue Scale (VAS) and a radiographic evaluation including a long-leg radiograph. Primary outcome measure was patient satisfaction based on the Forgotten Joint Score. RESULTS: We found an excellent postoperative health-related quality of life with a mean FJS of 76.8 (SD 17.9) indicating a low level of joint awareness after CM-UKA. The mean preoperative KSS was 66.0 (SD 13.71) and 59.4 (17.9) for the KSS function score. The increase was 22.8 points for the KSS knee score (p < 0.0001) and 34.8 points for the KSS function score (p < 0.0001). The VAS for pain decreased from a mean of 5.4 (SD 1.8) to 1.1 (SD 1.2) (p < 0.0001). The malalignment rate with a postoperative deviation of more than 2° in the leg axis was 29%. There was no evidence of component loosening after a mean follow-up of 2.4 years. CONCLUSIONS: Custom-made unicondylar knee arthroplasty (CM-UKA) can provide improved clinical and functional outcomes for patients with isolated knee osteoarthritis of the medial compartment. We found excellent results regarding patient satisfaction and a low malalignment rate for CM-UKA. Further studies are needed to investigate long-term survivorship of the implant. LEVEL OF EVIDENCE: Level IV. TRIAL REGISTRATION: Trial Registration number: Z-2014-0389-10 Regensburg Clinical Studies Center (REGCSC) 09/07/2014.

Spectrum of Tendon Pathologies: Triggers, Trails and End-State.

The biggest compartment of the musculoskeletal system is the tendons and ligaments. In particular, tendons are dense tissues connecting muscle to bone that are critical for the integrity, function and locomotion of this system. Due to the increasing age of our society and the overall rise in engagement in extreme and overuse sports, there is a growing prevalence of tendinopathies. Despite the recent advances in tendon research and due to difficult early diagnosis, a multitude of risk factors and vague understanding of the underlying biological mechanisms involved in the progression of tendon injuries, the toolbox of treatment strategies remains limited and non-satisfactory. This review is designed to summarize the current knowledge of triggers, trails and end state of tendinopathies.

Attenuation of Hypertrophy in Human MSCs via Treatment with a Retinoic Acid Receptor Inverse Agonist.

In vitro chondrogenically differentiated mesenchymal stem cells (MSCs) have a tendency to undergo hypertrophy, mirroring the fate of transient "chondrocytes" in the growth plate. As hypertrophy would result in ossification, this fact limits their use in cartilage tissue engineering applications. During limb development, retinoic acid receptor (RAR) signaling exerts an important influence on cell fate of mesenchymal progenitors. While retinoids foster hypertrophy, suppression of RAR signaling seems to be required for chondrogenic differentiation. Therefore, we hypothesized that treatment of chondrogenically differentiating hMSCs with the RAR inverse agonist, BMS204,493 (further named BMS), would attenuate hypertrophy. We induced hypertrophy in chondrogenic precultured MSC pellets by the addition of bone morphogenetic protein 4. Direct activation of the RAR pathway by application of the physiological RAR agonist retinoic acid (RA) further enhanced the hypertrophic phenotype. However, BMS treatment reduced hypertrophic conversion in hMSCs, shown by decreased cell size, number of hypertrophic cells, and collagen type X deposition in histological analyses. BMS effects were dependent on the time point of application and strongest after early treatment during chondrogenic precultivation. The possibility of modifing hypertrophic cartilage via attenuation of RAR signaling by BMS could be helpful in producing stable engineered tissue for cartilage regeneration.

Changes of Material Elastic Properties during Healing of Ruptured Achilles Tendons Measured with Shear Wave Elastography: A Pilot Study.

Therapy options for ruptured Achilles tendons need to take into account the right balance of timing, amount and intensity of loading to ensure a sufficient biomechanical resilience of the healing tendon on the one hand, and to enable an adequate tensile stimulus on the other hand. However, biomechanical data of human Achilles tendons after rupture during the separate healing stages are unknown. Shear wave elastography is an ultrasound technique that measures material elastic properties non-invasively, and was proven to have a very good correlation to biomechanical studies. Taking advantage of this technology, 12 patients who suffered from an acute Achilles tendon rupture were acquired and monitored through the course of one year after rupture. Nine of these patients were treated non-operatively and were included for the analysis of biomechanical behaviour. A significant increase of material elastic properties was observed within the first six weeks after trauma (up to 80% of baseline value), where it reached a plateau phase. A second significant increase occurred three to six months after injury. This pilot study suggests a time correlation of biomechanical properties with the biological healing phases of tendon tissue. In the reparative phase, a substantial amount of biomechanical resilience is restored already, but the final stage of biomechanical stability is reached in the maturation phase. These findings can potentially be implemented into treatment and aftercare protocols.

Fetal weight estimation at term - ultrasound versus clinical examination with Leopold's manoeuvres: a prospective blinded observational study.

BACKGROUND: Fetal weight estimation is of key importance in the decision-making process for obstetric planning and management. The literature is inconsistent on the accuracy of measurements with either ultrasound or clinical examination, known as Leopold's manoeuvres, shortly before term. Maternal BMI is a confounding factor because it is associated with both the fetal weight and the accuracy of fetal weight estimation. The aim of our study was to compare the accuracy of fetal weight estimation performed with ultrasound and with clinical examination with respect to BMI. METHODS: In this prospective blinded observational study we investigated the accuracy of clinical examination as compared to ultrasound measurement in fetal weight estimation, taking the actual birth weight as the gold standard. In a cohort of all consecutive patients who presented in our department from January 2016 to May 2017 to register for delivery at ≥37 weeks, examination was done by ultrasound and Leopold's manoeuvres to estimate fetal weight. All examiners (midwives and physicians) had about the same level of professional experience. The primary aim was to compare overall absolute error, overall absolute percent error, absolute percent error > 10% and absolute percent error > 20% for weight estimation by ultrasound and by means of Leopold's manoeuvres versus the actual birth weight as the given gold standard, namely separately for normal weight and for overweight pregnant women. RESULTS: Five hundred forty-three patients were included in the data analysis. The accuracy of fetal weight estimation was significantly better with ultrasound than with Leopold's manoeuvres in all absolute error calculations made in overweight pregnant women. For all error calculations performed in normal weight pregnant women, no statistically significant difference was seen in the accuracy of fetal weight estimation between ultrasound and Leopold's manoeuvres. CONCLUSIONS: Data from our prospective blinded observational study show a significantly better accuracy of ultrasound for fetal weight estimation in overweight pregnant women only as compared to Leopold's manoeuvres with a significant difference in absolute error. We did not observe significantly better accuracy of ultrasound as compared to Leopold's manoeuvres in normal weight women. Further research is needed to analyse the situation in normal weight women.

Novel implant-free loop Tenodesis vs. simple Tenotomy of the long biceps tendon - a biomechanical investigation.

BACKGROUND: Simple tenotomy and anchor tenodesis are commonly used in treatment of long biceps tendon (LHB) pathologies. The tenotomy can result in biceps distalization or cosmetic deformities. A novel loop Tenodesis Technique (LTD) could prevent a distalization of the biceps muscle without the risk of implant associated complications. The purpose of this study was to investigate the biomechanical aspects of the novel LTD compared to a standard tenotomy of the LHB. It has been hypothesized that the novel technique will show biomechanical superiority in terms of resistance and distalization. METHODS: Seven paired adult human cadaveric shoulder joints were assigned to one of the two study groups: Loop tenodesis (LTD); simple tenotomy (STT). In both groups load-to-failure testing was performed. The load-displacement curve was used to determine the maximum load (N), the degree of distalization of the LHB (mm) and the stiffness (N/mm). Additionally, the mode of failure was registered. RESULTS: The LTD group achieved a significantly higher ultimate load to failure (LTD: 50.5 ± 12.5 N vs. STT: 6.6 ± 3.9 N; p = 0.001). Significantly less distalization of the tendon could be detected for the LTD group (LTD: 8 ± 2.3 mm vs. STT: 22.4 ± 2.4 mm; p = 0.001). Stiffness was 7.4 ± 3.9 N/mm for the LTD group and 0.23 ± 0.16 N/mm for the STT group (p = 0.001). In all specimens of the LTD group a tendon rupture was found as mode of failure, while the STT group failed because of pulling out the LHB through the bicipital groove. CONCLUSION: The novel loop Tenodesis Technique shows biomechanically higher stability as well as less distalization compared to a simple tenotomy of the long biceps tendon.

Bone Marrow Aspirate Concentrate for the Treatment of Avascular Meniscus Tears in a One-Step Procedure-Evaluation of an In Vivo Model.

Avascular meniscus tears show poor intrinsic regenerative potential. Thus, lesions within this area predispose the patient to developing knee osteoarthritis. Current research focuses on regenerative approaches using growth factors or mesenchymal stem cells (MSCs) to enhance healing capacity within the avascular meniscus zone. The use of MSCs especially as progenitor cells and a source of growth factors has shown promising results. However, present studies use bone-marrow-derived BMSCs in a two-step procedure, which is limiting the transfer in clinical praxis. So, the aim of this study was to evaluate a one-step procedure using bone marrow aspirate concentrate (BMAC), containing BMSCs, for inducing the regeneration of avascular meniscus lesions. Longitudinal meniscus tears of 4 mm in size of the lateral New Zealand White rabbit meniscus were treated with clotted autologous PRP (platelet-rich plasma) or BMAC and a meniscus suture or a meniscus suture alone. Menisci were harvested at 6 and 12 weeks after initial surgery. Macroscopical and histological evaluation was performed according to an established Meniscus Scoring System. BMAC significantly enhanced regeneration of the meniscus lesions in a time-dependent manner and in comparison to the PRP and control groups, where no healing could be observed. Treatment of avascular meniscus lesions with BMAC and meniscus suturing seems to be a promising approach to promote meniscus regeneration in the avascular zone using a one-step procedure.

Reattachment of the flexor and extensor tendons at the epicondyle in elbow instability: a biomechanical comparison of techniques.

BACKGROUND: Elbow dislocation represents a common injury, especially in the younger population. If treated surgically, the reattached tendons require a high amount of primary stability to allow for an early rehabilitation to avoid postoperative stiffness. The purpose of this study was to assess the biomechanical properties of a single and a double row technique for reattachment of the common extensor and common flexor muscles origin. We hypothesized that the double row technique would provide greater stability in terms of pullout forces than the single row technique. METHODS: Twelve cadaveric specimens were randomized into two groups of fixation methods for the common extensor tendon or the common flexor tendon at the elbow (1): a single row technique using two knotted 3.0 mm suture anchors, and (2) a double row technique using an additional knotless 3.5 mm anchor. The repairs were cyclically loaded over 500 cycles at 1 Hz from 10 N to a maximum of 100 N (extensors) or 150 N (flexors), and then pulled to failure. Stiffness and maximum load at failure and mode of failure were recorded and calculated. RESULTS: No significant differences in stiffness were observed between the two techniques for both the extensor and flexor reattachment (P = 0.701 and P = 0.306, respectively). The mean maximum load at failure indicated that the double row construct was significantly stronger than the single row construct. This was found to be true for both the extensor and flexor reattachment (213.6; SD 78.7 N versus 384.1; SD 105.6 N, P = 0.010 and 203.7; SD 65.8 N versus 318.0; SD 64.6 N, P = 0.013, respectively). CONCLUSIONS: The double row technique provides significant greater stability to the reattached common flexor or extensor origin to the medial or lateral epicondyle. Thus, it should be considered in the development of improved repair techniques for stabilizers of the elbow. STUDY DESIGN: Controlled laboratory study.

In Vitro Comparison of 2D-Cell Culture and 3D-Cell Sheets of Scleraxis-Programmed Bone Marrow Derived Mesenchymal Stem Cells to Primary Tendon Stem/Progenitor Cells for Tendon Repair.

The poor and slow healing capacity of tendons requires novel strategies to speed up the tendon repair process. Hence, new and promising developments in tendon tissue engineering have become increasingly relevant. Previously, we have established a tendon progenitor cell line via ectopic expression of the tendon-related basic helix-loop-helix (bHLH) transcription factor Scleraxis (Scx) in human bone marrow mesenchymal stem cells (hMSC-Scx). The aim of this study was to directly compare the characteristics of hMSC-Scx cells to that of primary human tendon stem/progenitors cells (hTSPCs) via assessment of self-renewal and multipotency, gene marker expression profiling, in vitro wound healing assay and three-dimensional cell sheet formation. As expected, hTSPCs were more naive than hMSC-Scx cells because of higher clonogenicity, trilineage differentiation potential, and expression of stem cell markers, as well as higher mRNA levels of several gene factors associated with early tendon development. Interestingly, with regards to wound healing, both cell types demonstrate a comparable speed of scratch closure, as well as migratory velocity and distance in various migration experiments. In the three-dimensional cell sheet model, hMSC-Scx cells and hTSPCs form compact tendinous sheets as histological staining, and transmission electron microscopy shows spindle-shaped cells and collagen type I fibrils with similar average diameter size and distribution. Taken together, hTSPCs exceed hMSC-Scx cells in several characteristics, namely clonogenicity, multipotentiality, gene expression profile and rates of tendon-like sheet formation, whilst in three-dimensional cell sheets, both cell types have comparable in vitro healing potential and collagenous composition of their three-dimensional cell sheets, making both cell types a suitable cell source for tendon tissue engineering and healing.