Midterm Development of Ultrasound-unstable Hip Joints After Overhead Traction and Treatment With Tübingen Splint and Fettweis Plaster: A Radiologic Follow-up Analysis Over 5.5 Years.

PURPOSE: The aim of this study was to determine the success rate for treatment of ultrasound unstable hips (type D, III and IV) with Fettweis plaster in terms of a midterm follow-up from the very beginning in the neonatal period until the age of 4 to 8 years. METHODS: In total, 69 unstable hips, which were successfully treated with Fettweis plaster and after with a flexion-abduction splint, were included into the study. Hip delvelopment was followed by determining the acetabular index (ACI) on routine pelvic radiographs at the age of 12 to ≤24, 24 to ≤48 and 48 to ≤96 months and the center edge angle on the latter, and classifying both angles according to Tönnis. RESULTS: After initially successful treatment, the first radiograph at the age of 12 to ≤24 months showed 39.1% (n=27) hips with normal findings, 33.2% (n=23) hips with slightly dysplastic findings, and 27.5% (n=19) hips with severe dysplastic findings. Comparison between first and second radiograph showed improvement of the ACI in 9/69 hips and between the second and third time point in 20/69 hips. Overall, 20 hip joints showed deteriorations. Hereby, 16 deteriorations took place after the first radiograph and 4 after the second radiograph. Deteriorations were observed independently of the initial hip type (D, III, and IV). CONCLUSIONS: Midterm results indicate that radiologic controls should be provided to detect deteriorations after finishing treatment. ACI and center edge angle are helpful parameters in the assessment of hip joint development in the age range of 4 to 8 years. LEVEL OF EVIDENCE: Level III.

Radiological long-term follow-up up to 12 years of initially ultrasound unstable hip types D, III and IV after treatment with the Tübingen splint worn as a plaster.

INTRODUCTION: The treatment of ultrasound unstable hips with the Tübingen splint is currently under discussion. However, there is a lack of long-term follow-up data. This study presents to the best of our knowledge first radiological mid-term to long-term data of the successful initial treatment with the Tübingen splint of ultrasound unstable hips. MATERIALS AND METHODS: From 2002 to 2022 the treatment of ultrasound unstable hips type D, III and IV (age ≤ 6 weeks, no severe limitation of abduction) with the Tübingen splint worn as a plaster is evaluated. Based on data derived from routine X-rays during the follow-up period, a radiological follow-up (FU) analysis until the age of 12 years was performed. The acetabular index (ACI) and center-edge angle (CEA) were measured and classified according to Tönnis as normal findings (NF), slightly (sliD) or severely dysplastic (sevD). RESULTS: 193 of 201 (95.5%) unstable hips could be successfully treated showing normal findings with an alpha angle > 65°. The few patients showing treatment failures were successfully treated applying a Fettweis plaster (human position) under anesthesia. The radiological FU of 38 hips showed a favorable trend with increase of normal findings from 52.8% to 81.1% and decrease of 38.9% to 19.9% of sliD respectively 8.3% to 0% of sevD hips. The analysis of avascular necrosis of the femoral head showed 2 cases (5.3%) of grade 1 according to Kalamchi and McEwen, which were improving over time in the further course. CONCLUSIONS: The Tübingen splint as alternative to replace a plaster has proven a successful therapeutic option for ultrasound unstable hips type D, III and IV with favorable and over time improving radiological parameter up to the age of 12 years.

Rifampicin has - Compared to clindamycin - A dose and time dependent effect on hMSCs during osteogenic differentiation in vitro.

BACKGROUND: The effects of rifampicin and clindamycin on human mesenchymal stromal cell (hMSC) were examined. METHODS: hMSC were cultured with rifampicin and clindamycin (0.5 µg/ml, 5 µg/ml, 50 µg/ml) and examinations of proliferation (Bromodeoxyuridine), calcification (Alizarin red) and mineralization (alkaline phosphatase) were performed after 7th, 14th and 21st days. RESULTS: With rifampicin (50 µg/ml) cultured hMSC showed a significant negative effect during proliferation, mineralization (7, 14 and 21 days) and calcification (21 days). Clindamycin seems to have no effect. CONCLUSIONS: Rifampicin in a dosage of 50 µg/ml showed a negative impact on proliferation, mineralization and calcification of hMSC after 21 days.

Treatment of unstable hips with the Tübingen splint in early postnatal period: radiological mid-term results of 75 hips with mean follow-up of 5.5 years.

PURPOSE: For treatment of unstable hips, the Tübingen splint is a treatment option. After the initial treatment, regular radiological follow-up examinations are recommended but there is a lack of long-term outcome studies. Therefore, the further development of unstable hips treated with the Tübingen splint were evaluated. METHODS: From 2004 to 2015 116 patients with 161 unstable hips treated with the Tübingen splint were evaluated. Inclusion criteria were: 1) successfully treated unstable hip (type D, III and IV); 2) pelvic radiographs at the age of one to ≤ two, two to ≤ four and four to ≤ eight years. The acetabular index (ACI) of all and the centre-edge angle (CEA) of the third radiograph were measured and classified according to the Tönnis classification. RESULTS: A total of 53 patients with 75 unstable hips (type D 34 (45.3%), III 33 (44.0%), IV 8 (10.7%)) were included. In comparison of the first, second and third radiograph, an increase of normal findings was seen in 31 (41.3%) to 53 (70.7%) and 60 (80.0%) hips, respectively. However, a decrease of slightly dysplastic hips from 31 (41.3%) to 19 (25.3%) and 14 (18.7%) respectively and severely dysplastic hips from 13 (17.3%) to three (4.0%) and one (1.3%) hip respectively was detected. In comparison of first to second radiograph, 32 hips improved and five hips deteriorated and of second to third radiograph 16 hips improved and six hips deteriorated. The Tönnis classification of ACI compared with CEA showed no significant differences (p = 0.442). CONCLUSION: This study shows a good development of unstable hips treated with the Tübingen splint with mean follow-up 5.5 years. Nevertheless, unexpected deteriorations could be identified. The CEA is an alternative to the ACI. LEVEL OF EVIDENCE: IV.

Histologic examination of the shoulder capsule shows new layer of elastic fibres between synovial and fibrous membrane.

PURPOSE: In the present study, a systematic histological analysis of the glenohumeral joint capsule was conducted. MATERIALS AND METHODS: 12 cadaveric shoulders were examined. Inclusion criteria were: 1) intact joint capsule and 2) fixation in neutral position. The tissue samples were Elastica Hematoxylin-van-Gieson-(ElHvG) stained and diameter, quantity, and distribution patterns were analyzed. RESULTS: We detected a new layer (elastic boundary layer, EBL) between the synovial and fibrous membrane. The elastic fibres of the EBL differ considerably in diameter, quantity, and distribution pattern. CONCLUSIONS: A previously undescribed layer was noticed, which we named elastic boundary layer for now.

Outcome after subtalar screw arthroereisis in children with flexible flatfoot depends on time of treatment: Midterm results of 95 cases.

OBJECTIVES: The subtalar screw arthroereisis (SSA) is a treatment option for painful pediatric flexible flatfeet (PFF). Hence, the optimal time point for a SSA is discussed controversially. Therefore the present study evaluates the influence of the patient's age at surgery on the radiological outcome to provide further evidence in this matter. METHODS: From 08/2007 to 12/2015 50 patients with 95 PFF were included. Inclusion criteria were: 1) Patients with PFF under or equal 15 years of age, 2) treatment with SSA and 3) presence of pre-op, post-op and follow up (FU) routine biplane radiographs. A subdivision was made into group A: 5-8 years, group B: 9-12 years and group C: 13-15 years. The radiographs were analyzed for: 1) calcaneal-pitch (CP), 2) lateral talocalcaneal angle (lat. TCA), 3) a.p. talocalcaneal angle (a.p. TCA, kite angle) and 4) navicular-cuboidal-index (NCI) and meary angle. RESULTS: Our study showed the best deformity correction when surgery was conducted between 9 and 12 years of age (group B), with significant improvement in all measured parameters without secondary deterioration during FU. In group A, the SSA show inferior results with poorer long-term success with only an improvement in the a.p. TCA. Group C showed mixed results. While CP and NCI improved, the lat. TCA deteriorated in FU. In conclusion, the ideal age for surgical intervention by SSA is between 9 and 12 years. Surgery before the age of 8 years did not show long-term success and delayed treatment at the age of 13-15 was only partially successful with deterioration during FU period. LEVEL OF EVIDENCE: IV.

Blood supply in the bicipital groove: A histological analysis.

The vascular anatomy in the closed bicipital groove with the long head of the biceps brachii muscle tendon (LHBT), its mesotenon and the transverse ligament intact has not been analyzed on a histological level yet. An anatomic dissection and histologic study was conducted by using 24 cadaveric formaldehyde fixated shoulders. The bicipital groove including the LHBT and its intact sheath was cut en-bloc, fixated, sliced in 7 µm sections, Azan stained and the vascular anatomy analyzed under light microscopy. Each sideward branch deriving from the main ascending branches of the anterior humeral circumflex artery (ACHA) in the mesotenon of the LHBT was identified and followed through multiple sections to identify its direction and area of supply. Per specimen, a mean of 2.71±1.85 branches could be identified running through the soft tissue of the mesotenon towards the osseous walls of the groove. Of the total 65 arterial branches in all specimens, 22 (33.8%) were running into the medial wall of the groove and 40 (61.5%) into the lateral wall (P<0.01). The results indicate that branches of the ACHA in the mesotenon of the LHBT provide blood supply not only to the tendon but to the osseous bicipital groove as well and here significantly more to the lateral than to the medial osseous wall. In addition, Pacini-like mechanoreceptors could be identified in the mesotenon in 9 (37.5%) of the specimens which has not been described up to now.

MRI reveals unrecognized treatment failures after application of Fettweis plaster in children with unstable hip joints.

We evaluated the success of treatment of unstable hip joints with the Fettweis plaster followed by MRI to detect potential treatment failures. A total of 132 ultrasound-detected unstable hips of type D, III, or IV according to Graf were treated with closed reduction and Fettweis plaster, followed by MRI. We examined 19 type D, 55 type III, and 58 type IV. Mean age at diagnosis was 84.5 days (SD: ± 55.4). Treatment period was 63.2 days (SD: ± 22.2). In 13 cases, the MRI showed a poor reduction. After repetition of this treatment, all 13 showed a concentric reduction. The use of MRI detects 9.8% of treatment failures. We recommend an MRI examination after each closed reduction to ensure the success of the therapy.

Improving results in rat fracture models: enhancing the efficacy of biomechanical testing by a modification of the experimental setup.

BACKGROUND: Animal fracture models, primarily performed in rats, are crucial to investigate normal and pathological bone healing. However, results of biomechanical testing representing a major outcome measure show high standard deviations often precluding statistical significance. Therefore, the aim of our study was a systematical examination of biomechanical characteristics of rat femurs during three-point bending. Furthermore, we tried to reduce variation of results by individually adapting the span of bearing and loading areas to the bone's length. METHODS: We examined 40 paired femurs of male Wistar-rats by DXA (BMD and BMC of the whole femur) and pQCT-scans at the levels of bearing and loading areas of the subsequent biomechanical three-point bending test. Individual adjustment of bearing and loading bars was done respecting the length of each specimen. Subgroups of light (< 400 g, n = 22) and heavy (> 400 g, n = 18) animals were formed and analysed separately. We furthermore compared the results of the individualised bending-setting to 20 femurs tested with a fix span of 15 mm. RESULTS: Femurs showed a length range of 34 to 46 mm. The failure loads ranged from 116 to 251 N (mean 175.4 ± 45.2 N; heavy animals mean 221 ± 18.9 N; light animals mean 138.1 ± 16.4 N) and stiffness ranged from 185 N/mm to 426 N/mm (mean 315.6 ± 63 N/mm; heavy animals mean 358.1 ± 34.64 N/mm; light animals mean 280.8 ± 59.85 N/mm). The correlation of densitometric techniques and failure loads was high (DXA R2 = 0.89 and pQCT R2 = 0.88). In comparison to femurs tested with a fix span, individual adaptation of biomechanical testing homogenized our data significantly. Most notably, the standard deviation of failure loads (221 ± 18.95 N individualized setting vs. 205.5 ± 30.36 N fixed) and stiffness (358.1 ± 34.64 N/mm individualized setting vs. 498.5 ± 104.8 N/mm fixed) was reduced by at least one third. CONCLUSIONS: Total variation observed in any trait reflects biological and methodological variation. Precision of the method hence affects the statistical power of the study. By simply adapting the setting of the biomechanical testing, interindividual variation could be reduced, which improves the precision of the method significantly.

Osteochondritis dissecans shows a severe course and poor outcome in patients with juvenile idiopathic arthritis: a matched pair study of 22 cases.

Juvenile osteochondritis dissecans (JOCD) and juvenile idiopathic arthritis (JIA) are both common diseases which may affect joints and bony structures in pediatric patients. In some cases, JOCD and JIA occur at the same time. In this study, the course of JOCD in patients with JIA was therefore evaluated to provide possible recommendations for further treatment opportunities and control examinations. From 06/2012 to 03/2018 55 children with JOCD with or without JIA were examined. Inclusion criteria were: (1) age ≤ 16 years, (2) diagnosis of a JOCD with or without JIA and (3) two routine MRI controls. The JOCD evaluation based on the classification according to Bruns and the measurement of the largest extent via MRI. 18 of these 55 children met our criteria: 11 JOCD findings of 7 patients with JIA (group A) were matched according to age and localization of JOCD to 11 patients without JIA (group B). Mean age of disease onset of JIA was 8.2 years (oligo JIA) and of JOCD 11.6 years. The mean time follow-up was 17.7 months. At all observation time points more JOCD findings (with stage III° and IV°, respectively) along with a significant deterioration was seen in group A compared to group B. The comparison of the last MRI control between group A and group B shows a significant smaller defect size (decrease of 54.5%, p = 0.028) in group B (97.9 ± 48.9 mm2) as in group A (185.1 ± 102.9 mm2). In comparison of first (169.7 ± 84.2 mm2) and last MRI (97.9 ± 48.9 mm2) a significant decrease in lesion size of JOCD in group B was seen (decrease of 58.4%, p = 0.048). Patients with JIA show a more progressive and severe course of JOCD. Therefore, we recommend (1) the early use of MRI in patients with JIA and persistent joint pain to detect potential JOCD and (2) in presence of JIA and JOCD regular MRI follow-up controls to identify deteriorating JOCD findings and prevent early joint destruction in pediatric patients.

Whole bone testing in small animals: systematic characterization of the mechanical properties of different rodent bones available for rat fracture models.

OBJECTIVES: Rat fracture models are extensively used to characterize normal and pathological bone healing. Despite, systematic research on inter- and intra-individual differences of common rat bones examined is surprisingly not available. Thus, we studied the biomechanical behaviour and radiological characteristics of the humerus, the tibia and the femur of the male Wistar rat-all of which are potentially available in the experimental situation-to identify useful or detrimental biomechanical properties of each bone and to facilitate sample size calculations. METHODS: 40 paired femura, tibiae and humeri of male Wistar rats (10-38 weeks, weight between 240 and 720 g) were analysed by DXA, pQCT scan and three-point-bending. Bearing and loading bars of the biomechanical setup were adapted percentually to the bone's length. Subgroups of light (skeletal immature) rats under 400 g (N = 11, 22 specimens of each bone) and heavy (mature) rats over 400 g (N = 9, 18 specimens of each bone) were formed and evaluated separately. RESULTS: Radiologically, neither significant differences between left and right bones, nor a specific side preference was evident. Mean side differences of the BMC were relatively small (1-3% measured by DXA and 2.5-5% by pQCT). Over all, bone mineral content (BMC) assessed by DXA and pQCT (TOT CNT, CORT CNT) showed high correlations between each other (BMC vs. TOT and CORT CNT: R2 = 0.94-0.99). The load-displacement diagram showed a typical, reproducible curve for each type of bone. Tibiae were the longest bones (mean 41.8 ± 4.12 mm) followed by femurs (mean 38.9 ± 4.12 mm) and humeri (mean 29.88 ± 3.33 mm). Failure loads and stiffness ranged from 175.4 ± 45.23 N / 315.6 ± 63.00 N/mm for the femurs, 124.6 ± 41.13 N / 260.5 ± 59.97 N/mm for the humeri to 117.1 ± 33.94 N / 143.8 ± 36.99 N/mm for the tibiae. Smallest interindividual differences were observed in failure loads of the femurs (CV% 8.6) and tibiae (CV% 10.7) of heavy animals, light animals showed good consistency in failure loads of the humeri (CV% 7.7). Most consistent results of both sides (left vs. right) in failure loads were provided by the femurs of light animals (mean difference 4.0 ± 2.8%); concerning stiffness, humeri of heavy animals were most consistent (mean difference of 6.2 ± 5%). In general, the failure loads showed strong correlations to the BMC (R2 = 0.85-0.88) whereas stiffness correlated only moderate, except for the humerus (BMC vs. stiffness: R2 = 0.79). DISCUSSION: Altogether, the rat's femur of mature specimens showed the most accurate and consistent radiological and biomechanical results. In synopsis with the common experimental use enabling comparison among different studies, this bone offers ideal biomechanical conditions for three point bending experiments. This can be explained by the combination of a superior aspect ratio and a round and long, straight morphology, which satisfies the beam criteria more than other bones tested.

Development of unstable hips after treatment with the Tübingen splint: mid-term follow-up of 83 hip joints.

INTRODUCTION: Early diagnosis and treatment of hip dysplasia are widely accepted as major factors for beneficial outcome. However, modalities for reduction and retention as well as for imaging are currently under clinical investigation. Local and general risk factors, e.g., breech presentation and the family's desire to avoid in-hospital treatment are major concerns in the decision-making process and consultation. For treatment of unstable hips in newborns the treatment with the Tübingen splint has proven good results in recent studies. However, mid- and long-term outcome studies are missing. We report on clinical results and X-ray parameter of initially unstable hips after treatment with the Tübingen splint at two time points: 12-24 and 24-48 months of age. MATERIALS AND METHODS: Included were newborns with 83 unstable hips (type D, III, IV according to Graf) which were successfully treated with the Tübingen splint-used as reduction splint 24 h per day/7 days per week-until type I hips were documented by ultrasound examination. Measurments are based on routine pelvic X-ray control at the age of 12-24 and 24-48 months. The acetabular angle was determined and according to the Tönnis-Classification evaluated into: normal findings (< 1 s), slightly dysplastic findings (1-2 s) and severely dysplastic findings (> 2 s). Children with secondary hip dysplasia were not included in this series. RESULTS: In 2nd year of life, 45 hips (54.2%; initial hip type D: 47.4%, III: 63.2%, IV: 42.9%) of the formerly unstable hips show normal X-ray findings. Although final ultrasound showed normal findings, at this time point 28 hips (33.7%; initial hip type D: 34.2%, III: 31.6%, IV: 42.9%) were slightly dysplastic and 10 (12.0%%; initial hip type D: 18.4%, III: 5.3%, IV: 14.3%) still severely dysplastic. At the age of 24-48 months, the percentage of radiologic normal hips had increased to 61 hips (73.5%; initial hip type D: 68.4%, III: 81.6%, IV: 57.1%), the number of slightly (19 hips) and severely dysplastic (3 hips) hips had decreased 22.9% (initial hip type D: 28.9%, III: 15.8%, IV: 28.6%) respectively 3.6% (initial hip type D: 2.6%, III: 2.6%, IV: 14.3%). At this time no operative intervention was neccessary. CONCLUSIONS: Our mid-term data show on the one hand a good development of unstable hips after successful treatment with the Tübingen splint. On the other hand despite successful therapy and normal ultrasound findings at the end of treatment further imaging by X-ray are mandatory to close follow-up and to detect those which might need surgical correction of residual dysplasia.

Lengthening of newly formed humerus after autologous fibula graft transplantation following intercalary tumor resection.

Secondary limb lengthening after intercalary bone resection in pediatric patients is still challenging. After the resection, a free fibula autograft can be used to reconstruct the osseous gap. However, in particular in young pediatric patients, insufficient growth of the epiphyseal plate after transplantation may lead to a significant limb-length discrepancy (LLD). In this case, the autograft was used for limb lengthening. We report on the lengthening of a humerus regenerate after fibula autograft transplantation into a humeral defect in a pediatric/young adolescent patient. Because of LLD, she underwent callus distraction of the humerus regenerate after transplantation of a fibula autograft using a unilateral external fixator device. An 18-year-old female patient with status postintercalary proliferating chondroma resection (at the age of 7 years) required treatment for correction of a 13 cm humerus shortening. She reported no pain, had no functional limitations, and had a full range of motion of the shoulder and elbow joint. She complained about her short humerus and overall body scheme. A unilateral external fixator device for callus distraction was applied to the transplanted humerus regenerate after free fibula autograft transplantation. Bone lengthening was performed by distraction (2×0.5 mm/day). After 62 days and a lengthening of 6 cm in total, bone distraction was stopped mainly to avoid any complication. At this time, there was no limitation in the range of motion. No nerve palsy or other problems occurred at any time of the distraction. In pediatric patients, the transplantation of a fibula autograft is a well-established option to bridge an osseous gap after intercalary bone resection. This case report shows that even the humerus regenerate after fibula autograft transplantation has excellent potential for callotasis and bone remodeling and therefore bone lengthening in patients with LLD is an option even after transplantation of an autograft. This method provides a new therapeutic option for patients with LLD after fibula transplantation.

Use of the Tübingen splint for the initial management of severely dysplastic and unstable hips in newborns with DDH: an alternative to Fettweis plaster and Pavlik harness.

AIM: Hip dysplasia is one of the most common skeletal disorders. As a late consequence 20-25% of the patients are at risk to develop secondary osteoarthritis and may require total hip replacement early in life. The treatment principles of hip dislocation are (1) concentric reposition, (2) retention, i.e., plaster in human post or Pavlik harness and (3) maturation in abduction flexion orthesis. The Tübingen splint was introduced as a further development of abduction devices for the treatment of (residual) hip dysplasia with stable hips. The advantages are easy handling, adjustment according to growth and safe limitation of abduction. The aim of this study was to determine the success of treatment of unstable hips with use of the Tübingen splint from early diagnosis until final end of therapy hence normal ultrasound findings. METHODS: From January 2003 to August 2016 79 children with 109 sonographic unstable hips were treated with the Tübingen splint initially consequently 24 h/day. Inclusion criteria were diagnosis of type D, type III a/b or type IV hips according to Graf and beginning of treatment at an age of less or equal 6 weeks, without limitation of abduction on clinical examination. RESULTS: At the time of diagnosis 51 type D (46.8%), 46 type III (42.2%) and 12 type IV (11.0%) hips were noticed. In 30 patients (38.0%) bilateral hip dysplasia (type D-IV) was diagnosed. 104 of 109 hips (95.4%) treated with the Tübingen splint could be transferred in a type I hip after a mean treatment period of 88.9 days (SD ± 26.0). In 5 cases (4.6%, 1 type III and 4 type IV hips) the treatment failed. CONCLUSION: Our data show, that successful treatment of unstable hips in neonates with the Tübingen splint is a comparably successful treatment modality relative to the Pavlik harness and Fettweis plaster.

Does Anticoagulant Medication Alter Fracture-Healing? A Morphological and Biomechanical Evaluation of the Possible Effects of Rivaroxaban and Enoxaparin Using a Rat Closed Fracture Model.

Low molecular weight heparin (LMWH) is routinely used to prevent thromboembolism in orthopaedic surgery, especially in the treatment of fractures or after joint-replacement. Impairment of fracture-healing due to increased bone-desorption, delayed remodelling and lower calcification caused by direct osteoclast stimulation is a well-known side effect of unfractioned heparin. However, the effect of LMWH is unclear and controversial. Recent studies strongly suggest impairment of bone-healing in-vitro and in animal models, characterized by a significant decrease in volume and quality of new-formed callus. Since October 2008, Rivaroxaban (Xarelto) is available for prophylactic use in elective knee- and hip-arthroplasty. Recently, some evidence has been found indicating an in vitro dose independent reduction of osteoblast function after Rivaroxaban treatment. In this study, the possible influence of Rivaroxaban and Enoxaparin on bone-healing in vivo was studied using a standardized, closed rodent fracture-model. 70 male Wistar-rats were randomized to Rivaroxaban, Enoxaparin or control groups. After pinning the right femur, a closed, transverse fracture was produced. 21 days later, the animals were sacrificed and both femora harvested. Analysis was done by biomechanical testing (three-point bending) and micro CT. Both investigated substances showed histomorphometric alterations of the newly formed callus assessed by micro CT analysis. In detail the bone (callus) volume was enhanced (sign. for Rivaroxaban) and the density reduced. The bone mineral content was enhanced accordingly (sign. for Rivaroxaban). Trabecular thickness was reduced (sign. for Rivaroxaban). Furthermore, both drugs showed significant enlarged bone (callus) surface and degree of anisotropy. In contrast, the biomechanical properties of the treated bones were equal to controls. To summarize, the morphological alterations of the fracture-callus did not result in functionally relevant deficits.

Cefazolin Irreversibly Inhibits Proliferation and Migration of Human Mesenchymal Stromal Cells.

Drugs may have a significant effect on postoperative bone healing by reducing the function of human mesenchymal stromal cells (hMSC) or mature osteoblasts. Although cefazolin is one of the most commonly used antibiotic drugs in arthroplasty to prevent infection worldwide, there is a lack of information regarding how cefazolin affects hMSC and therefore may have an effect on early bone healing. We studied the proliferation and migration capacity of primary hMSC during cefazolin treatment at various doses for up to 3 days, as well as the reversibility of the effects during the subsequent 3 days of culture without the drug. We found a time- and dose-dependent reduction of the proliferation rate and the migratory potential. Tests of whether these effects were reversible revealed that doses ≥ 250 µg/mL or treatments longer than 24 h irreversibly affected the cells. We are the first to show that application of cefazolin irreversibly inhibits the potential of hMSC for migration to the trauma site and local proliferation. Cefazolin should be administered only at the required dosage and time to prevent periprosthetic infection. If long-term administration is required and delayed bone healing is present, cefazolin application must be considered as a cause of delayed bone healing.

Effects of thromboprophylaxis on mesenchymal stromal cells during osteogenic differentiation: an in-vitro study comparing enoxaparin with rivaroxaban.

BACKGROUND: Low-molecular-weight heparins (e.g. Enoxaparin) are widely used to prevent venous thromboembolism after orthopaedic surgery, but there are reports about serious side effects including reduction in bone density and strength. In recent years new oral antithrombotic drugs (e.g. direct Factor Xa-inhibitor, Rivaroxaban) have been used to prevent venous thromboembolism. However, there is lack of information on the effects of these new drugs on human mesenchymal stromal cells during osteogenic differentiation and, therefore, effects during postoperative bone healing. METHODS: We evaluated the effects of Rivaroxaban and Enoxaparin on the proliferation, mRNA and surface receptor expression as well as differentiation capacity of primary human mesenchymal stromal cells during their osteogenic differentiation. RESULTS: Enoxaparin, but not Rivaroxaban treatment significantly increased human mesenchymal stromal cell (hMSC) proliferation during the first week of osteogenic differentiation while suppressing osteogenic marker genes, surface receptor expression and calcification. CONCLUSIONS: This is the first paper to demonstrate that Rivaroxaban had no significant influence on hMSC differentiation towards the osteogenic lineage, indicating a less affected bone healing process compared with Enoxaparin in vitro. Based on these findings Rivaroxaban seems to be superior to Enoxaparin in early stages of bone healing in vitro.

Bone Marrow Aspirate Concentrate in Combination With Intravenous Iloprost Increases Bone Healing in Patients With Avascular Necrosis of the Femoral Head: A Matched Pair Analysis.

With disease progression, avascular necrosis (AVN) of the femoral head may lead to a collapse of the articular surface. The exact pathophysiology of AVN remains unclear, although several conditions are known that can result in spontaneous cell death, leading to a reduction of trabecular bone and the development of AVN. Hip AVN treatment is stage-dependent in which two main stages of the disease can be distinguished: pre-collapse (ARCO 0-II) and post-collapse stage (ARCO III-IV, crescent sign). In the pre-collapse phase, core decompression (CD), with or without the addition of bone marrow (e.g. bone marrow aspirate concentrate, BMAC) or bone graft, is a common treatment alternative. In the post-collapse phase, THA (total hip arthroplasty) must be performed in most of the patients. In addition to surgical treatment, the intravenous application of Iloprost has been shown to have a curative potential and analgesic effect. From October 2009 to October 2014, 49 patients with AVN (stages I-III) were treated with core decompression at our institution. All patients were divided into group A (CD + BMAC) and group B (CD alone). Of these patients, 20 were included in a matched pair analysis. The patients were matched to age, gender, ARCO-stage, Kerboul combined necrotic angle, the cause of AVN, and whether Iloprost-therapy was performed. The Merle d'Aubigné Score and the Kerboul combined necrotic angle in a-p and lateral radiographs were evaluated pre- and postoperatively. The primary endpoint was a total hip arthroplasty. In group A, two patients needed THA while in group B four patients were treated with THA. In group A, the Merle d'Aubigné Score improved from 13.5 (pre-operatively) to 15.3 (postoperatively). In group B there was no difference between the pre- (14.3) and postoperative (14.1) assessment. The mean of the Kerboul angle showed no difference in both groups compared pre- to postoperatively (group A: pre-op 212°, postop 220°, group B: pre-op 213, postop 222°). Regarding radiographic evaluation, the interobserver variability revealed a moderate agreement between two raters regarding the pre-(ICC 0.594) and postoperative analysis (ICC 0.604).This study demonstrates that CD in combination with the application of autologous bone marrow aspirate concentrate into the femoral head seems to be a safe and efficient treatment alternative in the early stages of AVN of the femoral head when compared to CD alone.

Elastofibroma: clinical results after resection of a rare tumor entity.

Elastofibroma (EF) is a benign proliferation of connective tissue and is typically located at the dorsal thoracic wall. Most patients complain about pain during motion in the shoulder girdle. The aim of our study was to evaluate the outcome after surgical treatment of EF. This study provides an overview of typical clinical findings, diagnostics and pathogenesis of this rare entity. In this retrospective study we analyzed data of 12 patients (6 male, 6 female) with EF treated in our institution between 2004 and 2012. The mean follow-up was 4.7 years (range: 5 months to 7.5 years). All tumors were found to be unilateral and all patients had a negative medical history for EF. Visual analogue scale and range of motion (ROM) was documented pre- and postoperatively. In all patients indication for surgical resection was pain or uneasiness during movement. There was no statistically significant difference in ROM of the shoulder between pre- and postoperatively but all patients reported significantly less pain after surgical resection. Patients benefited from tumor resection by a significant reduction of pain levels and improvement of the motion-dependent discomfort.

Comparison of hip joint cartilage degeneration assessed by histology and ex vivo optical coherence tomography.

The aim of this study is to validate optical coherence tomography (OCT) in assessing human articular cartilage by means of histological analyses. Twenty resected human femoral head specimens were evaluated with OCT and histological analysis. OCT and histological evaluation was performed according to the Bear and the Mankin criteria. OCT grades and Mankin scores (total score and sub-score structure) were correlated and intra-/inter-observer agreement for repeated OCT evaluations was tested by interclass-correlation coefficient (ICC) analysis. OCT grades and Mankin scores were correlated [Spearman correlation=0.742 (total) and 0.656 (structure), P<0.001], revealing significant differences between the histological scores in various OCT grades of cartilage degeneration (P<0.001). Intra-observer (ICC 0.930) and inter-observer (ICC 0.933) reliability was high (P<0.001). OCT appears to be reliable in the assessment of human articular cartilage. Further studies on intra-operative cartilage evaluation by OCT are necessary to substantiate its applicability in clinical routine.