Cementing of the hip arthroplasty stem increases load-to-failure force: a cadaveric study.

Background and purpose - To date, there is not a single clinical or mechanical study directly comparing a cemented and a cementless version of the same stem. We investigated the load-to-failure force of a cementless and a cemented version of a double tapered stem. Material and methods - 10 femurs from 5 human cadaveric specimens, mean age 74 years (68-79) were extracted. Bone mineral density (BMD) was measured using peripheral quantitative computed tomography. None of the specimens had a compromised quality (average T value 0.0, -1.0 to 1.4). Each specimen from a pair randomly received a cemented or a cementless version of the same stem. A material testing machine was used for lateral load-to-failure test of up to a maximal load of 5.0 kN. Results - Average load-to-failure of the cemented stem was 2.8 kN (2.3-3.2) and 2.2 kN (1.8-2.8) for the cementless stem (p = 0.002). The cemented version of the stem sustained a higher load than its cementless counterpart in all cases. Failure force was not statistically significantly correlated to BMD (p = 0.07). Interpretation - Implanting a cemented version of the stem increases the load-to-failure force by 25%.

Objective assessment, repeatability, and agreement of shoulder ROM with a 3D gyroscope.

BACKGROUND: Assessment of shoulder mobility is essential for diagnosis and clinical follow-up of shoulder diseases. Only a few highly sophisticated instruments for objective measurements of shoulder mobility are available. The recently introduced DynaPort MiniMod TriGyro ShoulderTest-System (DP) was validated earlier in laboratory trials. We aimed to assess the precision (repeatability) and agreement of this instrument in human subjects, as compared to the conventional goniometer. METHODS: The DP is a small, light-weight, three-dimensional gyroscope that can be fixed on the distal upper arm, recording shoulder abduction, flexion, and rotation. Twenty-one subjects (42 shoulders) were included for analysis. Two subsequent assessments of the same subject with a 30-minute delay in testing of each shoulder were performed with the DP in two directions (flexion and abduction), and simultaneously correlated with the measurements of a conventional goniometer. All assessments were performed by one observer. Repeatability for each method was determined and compared as the statistical variance between two repeated measurements. Agreement was illustrated by Bland-Altman-Plots with 95% limits of agreement. Statistical analysis was performed with a linear mixed regression model. Variance for repeated measurements by the same method was also estimated and compared with the likelihood-ratio test. RESULTS: Evaluation of abduction showed significantly better repeatability for the DP compared to the conventional goniometer (error variance: DP = 0.89, goniometer = 8.58, p = 0.025). No significant differences were found for flexion (DP = 1.52, goniometer = 5.94, p = 0.09). Agreement assessment was performed for flexion for mean differences of 0.27° with 95% limit of agreement ranging from -7.97° to 8.51°. For abduction, the mean differences were 1.19° with a 95% limit of agreement ranging from -9.07° to 11.46°. CONCLUSION: In summary, DP demonstrated a high precision even higher than the conventional goniometer. Agreement between both methods is acceptable, with possible deviations of up to greater than 10°. Therefore, static measurements with DP are more precise than conventional goniometer measurements. These results are promising for routine clinical use of the DP.

Painful muscle fibrosis following synthol injections in a bodybuilder: a case report.

INTRODUCTION: Synthol is a site enhancement oil used by bodybuilders to boost the cosmetic appearance of muscles. Here, we describe the case of a patient with severe side effects following repeated intramuscular injections of synthol in his right biceps muscle. CASE PRESENTATION: A 29-year-old Middle Eastern male bodybuilder, following intramuscular injections of synthol five years ago, presented with painful pressure in his right upper arm. On presentation to our clinic, his muscle appeared disfigured. Magnetic resonance imaging revealed scattered cystic fatty lesions in the muscle. The affected part was surgically removed and histopathology showed inflammatory changes with fibrosis and a so-called Swiss cheese pattern. CONCLUSION: Synthol injections that are used for the short-term enhancement of muscle appearance by bodybuilders bear the danger of long-term painful muscle fibrosis and disfigurement.

Does probe frequency influence diagnostic accuracy in newborn hip ultrasound?

Ultrasonography of the hip has gained wide acceptance as reliable method for diagnosing developmental hip dysplasia in infants. This blinded study was conducted to investigate the influence of two linear probes with different frequency on diagnostic accuracy and reproducibility. In 206 consecutive newborns, the bony roof angle (α-angle) and cartilage roof angle (ß-angle) were assessed by three investigators according to Graf. The hips were measured twice both with a 7.5 MHz and a 12 MHz linear transducer (Sonoline G60S(®) ultrasound system; Siemens, Erlangen, Germany). Each investigator evaluated his sonograms 6 weeks later. Depending on the mean values for α-angle and ß-angle, the hips were classified. Reproducibility of the Graf classification was not found to be influenced. In two of three investigators, we observed significant improvement concerning variation of the ß-angle with the 12 MHz probe. The use of high-resolution transmitters may improve diagnostic accuracy in ultrasonography of the newborn's hip.

Torsional stability of interference screws derived from bovine bone--a biomechanical study.

BACKGROUND: In the present biomechanical study, the torsional stability of different interference screws, made of bovine bone, was tested. Interference screws derived from bovine bone are a possible biological alternative to conventional metallic or bioabsorbable polymer interference screws. METHODS: In the first part of the study we compared the torsional stability of self-made 8 mm Interference screws (BC) and a commercial 8 mm interference screw (Tutofix). Furthermore, we compared the torsional strength of BC screws with different diameters. For screwing in, a hexagon head and an octagon head were tested. Maximum breaking torques in polymethyl methacrylate resin were recorded by means of an electronic torque screw driver. In the second part of the study the tibial part of a bone-patellar tendon-bone graft was fixed in porcine test specimens using an 8 mm BC screw and the maximum insertion torques were recorded. Each interference screw type was tested 5 times. RESULTS: There was no statistically significant difference between the different 8 mm interference screws (p = 0.121). Pairwise comparisons did not reveal statistically significant differences, either. It was demonstrated for the BC screws, that a larger screw diameter significantly leads to higher torsional stability (p = 9.779 x 10(-5)). Pairwise comparisons showed a significantly lower torsional stability for the 7 mm BC screw than for the 8 mm BC screw (p = 0.0079) and the 9 mm BC screw (p = 0.0079). Statistically significant differences between the 8 mm and the 9 mm BC screw could not be found (p = 0.15). During screwing into the tibial graft channel of the porcine specimens, insertion torques between 0.5 Nm and 3.2 Nm were recorded. In one case the hexagon head of a BC screw broke off during the last turn. CONCLUSIONS: The BC screws show comparable torsional stability to Tutofix interference screws. As expected the torsional strength of the screws increases significantly with the diameter. The safety and in vivo performance of products derived from xenogeneic bone should be the focus of further investigations.

Comparison between bovine bone and titanium interference screws for implant fixation in ACL reconstruction: a biomechanical study.

INTRODUCTION: The application of interference screws for the fixation of bone-patellar tendon-bone (BPTB) grafts is a well-established technique in anterior-cruciate ligament reconstruction. Interference screws derived from bovine compact bone are a biological alternative to metallic or biodegradable polymer interference screws. MATERIALS AND METHODS: In 60 porcine specimens, the tibial part of an anterior-cruciate ligament reconstruction was performed using a BPTB graft. To secure the graft, either an 8-mm titanium interference screw or a self-made bovine interference screw (BC), or a commercial bovine compact bone screw (Tutofix) was used. The maximum failure load was determined by means of a universal testing machine with computer interface at a testing speed of 50 mm/min. In a second test series, cyclic sub-maximal load was applied to the test specimen from 40 to 400 N with a number of 1,000 load cycles and a frequency of 1 Hz. Subsequently, the maximum failure load was determined. The stiffness of the test specimen was investigated in both test series. Each type of interference screw was tested 10 times. RESULTS: A secure fixation of the grafts was achieved with all interference screws. In the experiments on the maximum load to failures, the titanium screws showed significantly higher failure loads than the Tutofix screws (P = 0.005). The stiffness of the grafts fixed with BC screws was significantly higher as compared to the fixation with Tutofix screws (P = 0.005). After cyclic sub-maximal loading, the maximum failure load of the titanium screws was significantly higher than that of the Tutofix screws (P = 0.033). The fixation of the BC screws showed a significantly higher failure load (P = 0.021) and stiffness (P = 0.032) than the Tutofix screw fixation. Except for two screw head fractures and two intra-tendinous graft ruptures, the failure mode was slippage in the interface between interference screw and bone plug. CONCLUSION: Interference screws derived from bovine compact bone show similar good results as the titanium interference screws. Therefore, the safety and in vivo performance of products derived from xenogenic bone should be the focus of further investigations.

RGD-functionalisation of PLLA nanofibers by surface coupling using plasma treatment: influence on stem cell differentiation.

The aim of this study was to functionalize the surface of synthetic poly-(l-lactic) (PLLA) nanofibers with RGD peptide, in order to promote growth and osteogenic differentiation of human mesenchymal stem cells (hMSC) in vitro. The cRGD was coupled onto PLLA nanofibers using oxygen plasma combined with EDC/sulfo-NHS activation. Matrices were seeded with hMSC and cultivated over a period of 22 days under growth conditions and analyzed during the course of cultivation. The plasma activation of PLLA nanofibers resulted in a reduction of hydrophobicity as well as a formation of carboxyl groups on the surface of the fibers. Furthermore, maximum load, but not young's modulus was influenced by the treatment with oxygen plasma. When hMSC were cultured onto the cRGD functionalized scaffolds, cells showed no increased proliferation or cell density but an induction of genes associated with the osteoblast lineage. In brief, this study indicates that functional peptides of the extracellular matrix can be coupled onto PLLA nanofibers using plasma treatment in combination with EDC/sulfo-NHS treatment. These groups are accessible for the growing cell and mediate probably some osteoinductive properties of collagen nanofibers.

Osseous hemangioma of the seventh cervical vertebra with osteoid formation mimicking metastasis: a case report.

INTRODUCTION: We report the case of an osseous hemangioma located in the seventh cervical vertebra with reactive osteoid formation and non-typical findings in the radiological and the histopathological examination, mimicking metastasis of a malignant tumor. To our knowledge, this is the first description of such a case in the literature. CASE PRESENTATION: A 44-year-old otherwise healthy Caucasian German woman presented with a discrete sensorimotor loss of both upper limbs. Radiologically, an osteolysis in the seventh cervical vertebra suggestive of metastasis of a malignant neoplasm was diagnosed. After performing corporectomy and cage implantation of C7 on the patient, the histopathological examination was complicated by marked osteoid formation obscuring the true diagnosis of an osseous hemangioma with reactive osteoid formation. CONCLUSION: Though hemangioma of the bone is a rare tumorous lesion in the cervical spine, it has to be taken into consideration as a reason for neck pain and sensomotoric loss of the upper limbs. Atypical radiological and histopathological presentations may hinder determination of the correct diagnosis. The treatment of such lesions must follow clinical guidelines but may be difficult to define in some cases when the correct diagnosis is not known at the time when therapy starts.

Clinical outcome and quality of life after computer-assisted total knee arthroplasty: results from a prospective, single-surgeon study and review of the literature.

Despite excellent results, there is a lack of prospective studies analysing functional outcome and quality of life after computer-navigated total knee arthroplasty. Fifty-two patients were investigated before and 6 months after surgery with the OrthoPilot navigation system (Aesculap, Germany). We used the SF-36 Health Survey, the visual analog scale (VAS), the Lequesne score and the Knee Society Score (KSS) for assessment. The operation was carried out by one single surgeon. At follow-up, the study population achieved a significant pain reduction on the VAS from 71 to 21 points, an average decline of the Lequesne score from 16 to 7 points coming along with a significant ascent of the KSS from 84 to 157 points. Concerning the SF-36 Health Survey, most of the patients re-achieved age- and gender-matched scores. Poor results were obtained in patients with multiple comorbidities and a severe flexion contracture preoperative.

Odontoid process metastasis of bronchial carcinoma as a rare cause for nonmechanical neck pain: a case report.

INTRODUCTION: About 10% of spinal metastases are found in the cervical level. Magnetic resonance imaging is the gold standard for early detection of spinal metastases. The decision whether cervical spine magnetic resonance imaging is requested or not must be made clinically, taking into consideration the patients' detailed pain history. CASE PRESENTATION: The case of an 85-year-old patient with a long history of neck pain caused by known multi-level cervical spine degeneration is presented. As conservative treatment became ineffective, he was sent for surgery. Pain character had changed from mechanical to nonmechanical. Therefore, new cervical Magnetic resonance imaging was requested, showing unexpected odontoid process osteolysis. Unknown lung cancer with adrenal and pancreatic metastases was revealed by further investigations. CONCLUSION: Detailed pain characterization can already indicate the correct diagnosis. In case of new onset cervical neck pain, magnetic resonance imaging should be performed soon, if pain is characterized as nonmechanical.

Liposarcoma of the forearm in a man with type 1 neurofibromatosis: a case report.

INTRODUCTION: The combination of neurofibromatosis and liposarcoma is very rare. We present a case of a dedifferentiated liposarcoma in the forearm, as a complication in a patient with neurofibromatosis type 1. CASE PRESENTATION: A Caucasian man with neurofibromatosis type 1 presented at our clinic complaining of a slow growing swelling on his left forearm over a period of one and a half years. Clinical examination and history pointed to malignancy. Radiological examination inclusive of magnetic resonance imaging and positron emission tomography confirmed our suspicion. A final diagnosis of dedifferentiated high-grade liposarcoma with axillary lymph node metastases was established after a pathological examination of a tumour biopsy. The consulting tumour board recommended either an elbow exarticulation or an accurate radical local resection including the metastatic axillary lymph nodes. Fortunately, we were able to perform an R-zero resection and the forearm could be saved. The treatment was completed with postoperative radiotherapy of the left forearm's operative bed, the left axillary and the supraclavicular regions. The patient decided against adjuvant chemotherapy. CONCLUSION: Liposarcoma complicating neurofibromatosis type 1 is a very rare combination. Up to now, only five cases have been reported in the literature. We are adding a new case to this short list to stress the importance of early recognition. It is the first known case with this disease combination in an upper extremity. Liposarcoma is usually treated by surgery followed by radiotherapy. The role of chemotherapy is controversial and should be based on a decision made on a case-by-case basis.

High- versus low-energy extracorporeal shock wave therapy of rotator cuff tendinopathy: a prospective, randomised, controlled study.

A prospective, controlled, randomised trial was performed to compare the effect of high-energy extracorporeal shock wave therapy (ESWT) versus low-energy ESWT in treatment of rotator cuff tendinopathy. Forty adult patients were included in the study. Patients in the intervention group received 6000 impulses of high-energy (ED+ 0.78 mJ/mm2) in 3 sessions under local anaesthesia. Patients in the control group received 6000 impulses of a low-energy ESWT (ED+ 0.33 mJ/mm2) under local anaesthesia. Follow-up examinations were performed 12 weeks and one year after treatment by an independent observer. An increase in function and a reduction of pain were found in both groups (p < 0.001). Although the improvement in Constant score was greater in the high-energy group compared to the low-energy group, statistical analyses showed no significant difference between the groups with respect to all parameters studied (Constant score/pain/subjective improvement) after 12 weeks and one year follow-up. No statistically significant differences were found between the results of high-energy and low-energy ESWT of rotator cuff tendinopathy.

Comparison of kyphoplasty and vertebroplasty in the treatment of fresh vertebral compression fractures.

INTRODUCTION: As life expectancy in the population rises, osteoporotic fractures are seen most frequently in the proximal femur and the vertebral column. In balloon kyphoplasty and vertebroplasty, we have two minimally invasive treatment procedures available. Although they have both been controversially discussed in studies, they have seldom been directly compared. MATERIALS AND METHODS: Between 2002 and 2004, patients with fresh thoracic or lumbar single-segment vertebral compression fractures not involving neurological deficits were treated by balloon kyphoplasty (n = 30) or vertebroplasty(n = 30) using PMMA cement, and the results of the two interventions were compared in a prospective, nonrandomised cohort study. Surgery was indicated when patients had painful, dislocated fractures of type A1 and type A3 according to Magerl's classification. The outcome of treatment was assessed with special reference to the angle of kyphosis, back pain (VAS), health-related quality of life (SF-36) and complications. RESULTS: At the time of the follow-up examination, significant improvement in the angle of kyphosis was found to have been achieved both by kyphoplasty and by vertebroplasty (P < 0.001 and P = 0.002, respectively). Comparison showed that correction of the angle was significantly (P < 0.001) better in the kyphoplasty group. Both surgical procedures led to significant (P < 0.001) attenuation of the patients' pain; no difference was observed between the groups in the degree of pain relief achieved. There was no demonstrable correlation in either group between the preoperative pain experienced by the patients and the degree of dislocation of their fractures. In both study groups, the quality of life was in keeping with that of a reference group matched for age and sex. Cement leakage was observed in 7% of patients after kyphoplasty and in 33% of patients after vertebroplasty (P = 0.021). Adjacent-level fractures were checked for, but occurred in only one patient in the vertebroplasty group. CONCLUSION: The two surgical procedures were both followed by significant pain relief, and the quality of life was similar regardless of the procedure used. Balloon kyphoplasty led to an ongoing reduction of freshly fractured vertebrae and was followed by a lower rate of cement leakage.

Effect of direct RGD incorporation in PLLA nanofibers on growth and osteogenic differentiation of human mesenchymal stem cells.

The aim of this study was to functionalize synthetic poly-(L-lactic) (PLLA) nanofibers by direct incorporation of cRGD, in order to promote adhesion, growth and osteogenic differentiation of human mesenchymal stem cells (hMSC) in vitro. The cRGD was incorporated into PLLA nanofibers either by emulsion [PLLA-cRGD (d)] or suspension [PLLA-cRGD (s)]. Matrices were seeded with hMSC and cultivated over a period of 28 days under growth conditions and analyzed during the course. Although the mode of incorporation resulted in different distributions of the RGD peptide, it had no impact on the fiber characteristics when compared to corresponding unblended PLLA control fibers. However, hMSC showed better adherence on PLLA-cRGD (d). Nevertheless, this advantage was not reflected during the course of cultivation. Furthermore, the PLLA-cRGD (s) fibers mediated the osteogenic potential of collagen (determined as the expression and deposition of collagen and osteocalcin) to some extent. Further studies are needed in order to optimize the RGD distribution and concentration.

Influence of nanofibers on the growth and osteogenic differentiation of stem cells: a comparison of biological collagen nanofibers and synthetic PLLA fibers.

The aim of this study was to compare biological collagen I (ColI) and synthetic poly-(L: -lactide) (PLLA) nanofibers concerning their stability and ability to promote growth and osteogenic differentiation of human mesenchymal stem cells in vitro. Matrices were seeded with human stem cells and cultivated over a period of 28 days under growth and osteoinductive conditions and analyzed during the course. During this time the PLLA nanofibers remained stable while the presence of cells resulted in an attenuation of the ColI nanofiber mesh. Although there was a tendency for better growth and osteoprotegerin production of stem cells when cultured on collagen nanofibers, there was no significant difference compared to PLLA nanofibers or controls. The gene expression of alkaline phosphate, osteocalcin and collagen I diminished in the initial phase of cultivation independent of the polymer used. In the case of PLLA fibers, this gene expression normalized during the course of cultivation, whereas the presence of collagen nanofibers resulted in an increased gene expression of osteocalcin and collagen during the course of the experiment. Taken together the PLLA fibers were easier to produce, more stable and did not compromise growth and differentiation of stem cells over the course of experiment. On the other hand, collagen nanofibers supported the differentiation process to some extent. Nevertheless, the need for fixation as well as the missing stability during cell culture requires further work.

Atypical manifestation of late onset limb girdle muscular dystrophy presenting with recurrent falling and shoulder dysfunction: a case report.

INTRODUCTION: Myopathies can be sub-classified into congenital, hereditary, mitochondrial, and secondary myopathies.Congenital myopathies are usually diagnosed post partal or in early childhood. Manifestation in adolescence is uncommon and most cases occur as sporadic mutations. Therefore, there is a risk of under diagnosing this disease in middle-aged patients showing pain, dysfunction, recurrent trauma or falls, where muscle atrophy is seen as a secondary injury. CASE PRESENTATION: Our report is about a 54 year old Caucasian woman with an extended history of pain, loss of function and weakness in her right shoulder. The clinical picture showed a frozen right shoulder. The main finding was a marked limb-muscle atrophy of both delta- und biceps-muscles and a rotator cuff tear that had developed over years. Previous medical consultations attributed the atrophy to recurrent falls, shoulder dysfunction and pain. Conservative treatment (analgesics, physiotherapy, training) had failed.The familiar anamnesis was free of any neurological diseases or other genetic diseases.MRI showed a sub-total proximal muscular limb atrophy and a rotator cuff tear in both shoulders. An incision-biopsy of the right delta- and biceps-muscle revealed a chronical myopathy. The level of creatinkinasis was expected to be high but measurements showed values only slightly above normal. Immunohistochemistry, eventually revealed a mild form of LGMD (type 2I). Due to the pattern of symptoms and diagnostic results we described the case as atypical LGMD. CONCLUSION: Our case presents a phenotype of a late onset of limb girdle muscular dystrophy syndrome associated with shoulder pain and dysfunction and recurrent falls. This kind of disease is not very common. In particular, muscle atrophy in the elderly is generally seen as a secondary injury. This case should remind us of the importance of a differential diagnosis of a late onset of muscular dystrophy-syndrome in the elderly, since an early diagnosis offers more treatment options, therefore preventing a rapid progression.