Avascular necrosis after chemotherapy for haematological malignancy in childhood

Avascular necrosis (AVN) is a serious complication of high-dose chemotherapy for haematological malignancy in childhood. In order to describe its incidence and main risk factors and to evaluate the current treatment options, we reviewed 105 children with a mean age of 8.25 years (1 to 17.8) who had acute lymphoblastic or acute myeloid leukaemia, or a non-Hodgkin’s lymphoma. Overall, eight children (7.6%) developed AVN after a mean of 16.8 months (8 to 49). There were four boys and four girls with a mean age of 14.4 years (9.8 to 16.8) and a total of 18 involved sites, 12 of which were in the femoral head. All these children were aged > nine years (p < 0.001). All had received steroid treatment with a mean cumulative dose of prednisone of 5967 mg (4425 to 9599) compared with a mean of 3943 mg (0 to 18 585) for patients without AVN (p = 0.005). No difference existed between genders and no thrombophilic disorders were identified. Their initial treatment included 11 core decompressions and two bipolar hip replacements. Later, two salvage osteotomies were done and three patients (four hips) eventually needed a total joint replacement. We conclude that AVN mostly affects the weight-bearing epiphyses. Its risk increases with age and higher steroid doses. These high-risk patients may benefit from early screening for AVN.

Cite this article: Bone Joint J 2013;95-B:1708–13.

[Sledge versus bicondylar surface treatment in the endoprosthetic therapy for unicompartmental knee arthrtitis--a comparative cost analysis]

BACKGROUND

The G-DRG system reimburses sledge endoprosthetic implantations (UKA) at a much lower rate than surface replacements (TKA), at significantly different cost weights (CW). Therefore, when only G-DRG payments are considered, the complete endoprosthesis implantation produces higher gains. An orientation on these revenues alone, however, does not provide the basis for an economically sound decision-making process. The aim of this study is to present a comparison of the variable costs of the two procedures.

MATERIAL AND METHODS

The mean cost and performance data of 28 Endo-Model UKA implantations and of 85 NexGen CR TKA replacements were compared with each other in 2007.

RESULTS

From the perspective of the hospital, when the correct medical indication is present, UKA treatment is of greater economic advantage. In this way the total unit contribution margin can be improved, and although the relative weighting is comparatively low, the costs are significantly lower than in a comparative analysis of the TKA.

CONCLUSION

For the desired maximisation of the unit contribution margin, assuming that it is the proper medical indication, the recommendation for the hospital would be implantation of the UKA. Considered from the economic perspective of gains and costs, the assumption that a TKA would be advantageous could not be confirmed in the present study.

[Gender-specific evaluation of student's career planning during medical study in terms of orthopaedic trauma]

BACKGROUND

Due to recent changes in the medical licencing act as well as to the introduction of a new model-course programme for medical studies, careers in medicine have become increasingly more attractive. However, there is still a dramatic shortage in younger generation physicians, especially within the surgical fields. The goal of this cross-sectional study was the gender-specific assessment of the ideal career wishes of students during medical school, with a focus being placed in orthopaedic trauma surgery.

MATERIALS AND METHODS

During the winter semester of 2010/2011 an online questionnaire (www.surveymonkey.com) was created for students enrolled in their 3rd to 12th semester (n=887). The questionnaire consisted of 50 questions [Likert scale (LS); 5 = agree, 1 = disagree] along with 10 free response questions. The scope of these questions ranged from personal career goals, within the context of their learning environment, to general life goals and planning. With regard to career choice, a differentiation was made between students' ideal career choices/subjects (IS), which were based solely on personal affinity, and so-called reality-based subjects (RS), which students considered more practical and to which they were more likely to apply in the future.

RESULTS

The response rate was 36,4% (n=323, 23,4 years, 6.3 semesters, 226 [70.0%] female [f] and 97 [30.0%] male [m]). A total of 206 students (63.8%; m=55.7% vs. f=66.7%; p=0.047) were able to pinpoint an IS, this percentage increased with increasing semester number (p=0.048). Overall, 29.1% of students indicated that their IS lay in the field of orthopaedic trauma, while 20.0% of men and 19.1% of women saw it as a realistic career path (RS). Throughout the course of their studies, from the 3rd semester to their practical year, a declining tendency was observed regarding the agreement between ideal and realistic career paths. Particularly evident was a decreasing interest in the field of orthopaedic trauma, beginning around the 9th semester and during the practical year, especially among the female student population. The reason for this shift seems multifactorial, ranging from concerns about family planning as well as the work load in a male-dominated field. By the time students enter their practical year, 13.5% of women and 15.4% of men were still certain in their choice to pursue a career in orthopaedic trauma (RS).

CONCLUSIONS

It seems that there is great interest in the fields of orthopaedic trauma among both female and male students in the middle portion of their studies. Women, especially, tend to prefer a specialisation in this operative field early in the course of their studies. However, this pool of potential successors decreases dramatically with time, due to personal experiences garnered on the wards, expectations regarding career paths (male-dominated, long hours) as well as concerns about family planning. The most dramatic shift seems to occur during the practical year.

Influence of estradiol on vascular endothelial growth factor expression in bone: a study in Göttingen miniature pigs and human osteoblasts

Ovariectomy (OVX) in animal models is an accepted method to simulate postmenopausal osteoprosis. Vascular endothelial growth factor (VEGF) has been recently shown to play an important role during endochondral bone formation, hypertrophic cartilage remodeling, ossification, and angiogenesis. We hypothesized that reduced VEGF expression in bone contributes to OVX-induced bone loss and tested it in a miniature pig model and in vitro using human osteoblasts. Seventeen primiparous sows (Göttingen miniature pigs) were allocated to two experimental groups when they were 30 months old: a control group (n = 9) and an OVX group (n = 8). After 15 months, VEGF levels in lumbar vertebrae were measured by enzyme-linked immunosorbent assay and verified by Western blot analysis. VEGF and its receptor (VEGFR) were localized by immunohistochemistry. Expression of VEGF mRNA was analyzed by real-time reverse-transcription polymerase chain reaction. Differently sulfated glycosaminoglycans were localized in subchondral bone histochemically. Osteoblasts were immunopositive for VEGF. VEGF concentration in the vertebra was 27% lower in OVX miniature pigs. VEGFR-2 could be immunostained on osteoblasts. VEGF mRNA and protein were detectable in the lumbar vertebrae of all animals. In subchondral trabecular bone of OVX animals, significantly more islands of mineralized cartilage containing chondroitin 4- and 6-sulfate or keratan sulfate occurred compared to the control group. The occurrence of remnants of mineralized cartilage in subchondral bone of the OVX group may be caused by a delayed bone turnover due to low VEGF levels. In vitro experiments revealed an increase of VEGF in the supernatant of osteoblasts after incubation with estradiol. In conclusion, estrogen seems to be a key factor for regulation of VEGF expression in bone. Loss of VEGF due to menopause may be a reason for reduction of bone density.

[Injuries in Olympic handball tournaments: a video analysis]

INTRODUCTION

The aim of the study was to achieve injury situations in European team handball with a video based method.

METHODS

A video tape containing 59 injuries of an Olympic handball tournament were analyzed by two observers (sports-scientist, orthopaedic surgeon). The analysis was based on a method previously published by Teitz, which was developed to analyze ACL-injuries. The parameters body region, field position, contact/non-contact, offense/defense, field player/goal keeper were mainly used.

RESULTS

The most injuries were localized at the head (N = 20), the lower limb (N = 15), thorax and abdomen (N = 9) and the upper limb (N = 9). Concerning the field, the most injuries were in the midfield (N = 20), followed by the left (N = 13) and right (N = 9) outside position. The injured players were mostly in the offense (84 %), and in the majority of cases the field players were affected (97 %). 86 % of the injuries accomplished by contact.

CONCLUSION

The head has a high risk, predominantly of contact injury. Contact-injuries could only be reduced by strict decisions of the referees. Non-contact injuries should be prevented by a special coordinative training.

["Shrinkage of cruciate ligaments"--a biomechanical study. Shrinkage of elongated cruciate ligaments using an application of radiofrequency energy]

The aim of this study was to evaluate structural properties of native and elongated bovine anterior cruciate ligaments after the application of bipolar radiofrequency. Using a material testing machine typical load-elongation curves were used to determine the initial strength of untreated (group 1, n = 20) and elongated cruciate ligaments (group 2, n = 20) after treatment with bipolar radiofrequency (ArthroCare). After the application of a cyclic loading protocol (1000 x 400 N) elongation, yield load, maximal load, and stiffness were determined. Native ligaments served as a control group (group 3, n = 20). In both groups 4 mm reduction in length was caused by the application of radiofrequency. Elongation was significantly higher; yield load, maximal load, and stiffness of cruciate ligaments treated with radiofrequency (groups 1 and 2) were significantly reduced after the application of a cyclic loading protocol in comparison to the control group (p < 0.05). Group 2 ligaments showed the lowest values. The application of radiofrequency weakens the biomechanical properties of native and elongated cruciate ligaments significantly. When radiofrequency energy is used to shrink elongated cruciate ligaments, a nonaggressive rehabilitation protocol should be applied.

Survival analysis of hips treated with flexion osteotomy for femoral head necrosis

The treatment of osteonecrosis of the femoral head (FHN) is controversial. It mainly occurs in young patients in whom total hip replacement is best avoided because of an increased risk of revision. The objective of this long-term follow-up study was to evaluate the outcome of intertrochanteric flexion osteotomy as a hip joint preserving operation for FHN. Over a 19-year period we carried out 70 intertrochanteric flexion osteotomies for FHN in 64 patients. The mean follow-up was 10.4 years (3.0 to 20.3). The overall mean Harris hip score increased from 51 points preoperatively to 71 points postoperatively. Six patients (9%) developed early postoperative complications. A total of 19 hips (27%) underwent total hip arthroplasty at a mean of 8.7 years after osteotomy. The five-year survival rate was 90%. Survival rates of hips in Ficat stage 2 were higher than those in stages 3 or 4. Hips with a preoperative necrotic angle of <200 degrees had a better survival probability than those with a necrotic angle >200 degrees. Our findings suggest that flexion osteotomy is a safe and effective procedure in Ficat stage 2 and 3 FHN, preferably with a necrotic angle of <200 degrees.

Dynamic gadolinium-enhanced MRI evaluation of porcine femoral head ischemia and reperfusion

OBJECTIVE

To examine the potential of gadolinium (Gd)-enhanced dynamic MRI in the detection of early femoral head ischemia. Furthermore, to apply a three-compartment model to achieve a clinically applicable MR index for femoral head perfusion during the steady state and arterial hip joint tamponade.

DESIGN AND MATERIALS

In a porcine model femoral head perfusion was measured by radioactive tracer microspheres and by using a dynamic Gd-enhanced MRI protocol. Femoral head perfusion measurements and MRI tests were performed unilaterally before, during and after the experimentally induced ischemia of one of the hip joints. Ischemia was induced by increasing intra-articular pressure to 250 mmHg.

RESULTS

All pigs showed ischemia of the femoral head epiphysis under hip joint tamponade followed by reperfusion to the same level as before joint tamponade. In two cases perfusion after removal of tamponade continued to be low. In dynamic MRI measurements increases in signal intensity were seen after intravenous infusion of Gd-DTPA, followed by a slow decrease in signal intensity. The signal-intensity curve during femoral head ischemia had a minor increase. Also the coefficient determined was a helpful indicator of femoral head ischemia.

CONCLUSIONS

Femoral head blood flow as measured by microspheres fell significantly under joint tamponade. Early detection of this disturbed regional blood flow was possible using a dynamic MRI procedure. A biomathematical model resulted from the evaluation of the intervals of signal intensity over time which allows detection of bone blood flow changes at a very early stage. Using this new method earlier detection of femoral head necrosis may be possible.

Selective reduction of bone blood flow by short-term treatment with high-dose methylprednisolone

Treatment with corticosteroids is a risk factor for non-traumatic avascular necrosis of the femoral head, but the pathological mechanism is poorly understood. Short-term treatment with high doses of methylprednisolone is used in severe neurotrauma and after kidney and heart transplantation. We investigated the effect of such treatment on the pattern of perfusion of the femoral head and of bone in general in the pig.

We allocated 15 immature pigs to treatment with high-dose methylprednisolone (20 mg/kg per day intramuscularly for three days, followed by 10 mg/kg intramuscularly for a further 11 days) and 15 to a control group. Perfusion of the systematically subdivided femoral head, proximal femur, acetabulum, humerus, and soft tissues was determined by the microsphere technique. Blood flow in bone was severely reduced in the steroid-treated group. The reduction of flow affected all the segments and the entire epiphysis of the femoral head. No changes in flow were found in non-osseous tissue. Short-term treatment with high-dose methylprednisolone causes reduction of osseous blood flow which may be the pathogenetic factor in the early stage of steroid-induced osteonecrosis.

Selective reduction of bone blood flow by short-term treatment with high-dose methylprednisolone. An experimental study in pigs

Treatment with corticosteroids is a risk factor for non-traumatic avascular necrosis of the femoral head, but the pathological mechanism is poorly understood. Short-term treatment with high doses of methylprednisolone is used in severe neurotrauma and after kidney and heart transplantation. We investigated the effect of such treatment on the pattern of perfusion of the femoral head and of bone in general in the pig. We allocated 15 immature pigs to treatment with high-dose methylprednisolone (20 mg/kg per day intramuscularly for three days, followed by 10 mg/kg intramuscularly for a further 11 days) and 15 to a control group. Perfusion of the systematically subdivided femoral head, proximal femur, acetabulum, humerus, and soft tissues was determined by the microsphere technique. Blood flow in bone was severely reduced in the steroid-treated group. The reduction of flow affected all the segments and the entire epiphysis of the femoral head. No changes in flow were found in non-osseous tissue. Short-term treatment with high-dose methylprednisolone causes reduction of osseous blood flow which may be the pathogenetic factor in the early stage of steroid-induced osteonecrosis.

Vertebral blood flow and bone mineral density during long-term corticosteroid treatment: An experimental study in immature pigs

STUDY DESIGN

Bone mineral density and regional blood flow were measured in pigs during long-term methylprednisolone treatment.

OBJECTIVES

To investigate possible changes in bone mineral density and vertebral blood flow during long-term glucocorticoid treatment.

SUMMARY OF BACKGROUND DATA

Steroid-induced vertebral osteonecrosis preferentially involves endplates and adjacent cancellous bone. The precise etiology of vertebral osteonecrosis during long-term glucocorticoid treatment is unknown.

METHODS

Twenty-four 10-week-old female Danish landrace sister pigs from 12 litters were treated in two groups. Twelve animals received oral methylprednisolone for 3 months at a daily dose of 100 mg. The 12 sister pigs received no steroid treatment and served as controls. Regional blood blow was measured by means of microspheres in predefined regions of the C6, T11, and L6 vertebrae. In vitro DEXA scanning of the L2-L4 vertebra was performed to assess bone mineral density.

RESULTS

Vertebral cancellous bone and endplate regional blood flow were decreased in the C6 and L6 vertebrae among corticosteroid-treated pigs compared with that of controls.- Width-adjusted lumbar vertebral bone mineral density (g/cm3) was unchanged, whereas projectional lumbar vertebral bone mineral density (g/cm2) was decreased in corticosteroid-treated pigs.

CONCLUSIONS

Long-term methylprednisolone treatment decreases vertebral bone blood flow mainly in cancellous bone and endplates. This may be an important factor in the pathogenesis of osteonecrosis secondary to glucocorticoid treatment. Lumbar vertebral bone mineral density was unchanged in growing pigs on long-term glucocorticoid treatment when expressed as volumetric bone density. The effect of glucocorticoid treatment on vertebral bone mineral density appears to depend on whether it is expressed as projectional (g/cm2) or volumetric bone mineral density (g/cm3). Vertebral and longbone growth was reduced during methylprednisolone treatment.

Reperfusion pattern of the immature femoral head after critical ischemia: a microsphere study in pigs

The topographic reperfusion pattern of the femoral head after critical ischemia has not yet been investigated. We determined the blood flow of the porcine hip regions with the femoral head epiphysis divided into 24 subregions by the tracer microsphere technique. Blood flow was measured under steady-state conditions, at the end of a 6-hour increase in intracapsular hip joint pressure to 250 mm Hg, and 4 hours after release of the joint tamponade. Total femoral head epiphyseal blood flow decreased with ischemia and regained steady-state perfusion after tamponade. The reperfusion pattern of the femoral head epiphysis appeared identical with that of the steady state before ischemia. However, 2 of the 11 experimental epiphyses remained ischemic in the reperfusion phase. We conclude that hip joint tamponade above the arterial pressure level for 6 hours causes global ischemia in the femoral head epiphysis in the immature pig, without regional differences in reperfusion, and that reperfusion occurs at a level like that of the steady state before ischemia.

The impact of vasoactive substances on intraosseous pressure and blood flow alterations in the femoral head: a study based on magnetic resonance imaging

In beagle dogs, the alterations of intraosseous pressure and blood supply in the femoral head that result from the administration of vasoactive substances were examined, and the changes were documented by magnetic resonance imaging (MRI). Vasoactive substance were infused into the medial and lateral circumflex femoral arteries of 12 beagle dogs. All infusions were done under standardised conditions with simultaneous measurements of venous blood flow and intraosseous pressure distribution in the proximal femur. The drugs were infused in three cycles of 30 min each separated by 30 min recovery periods, followed by MRI examination at the end of each experiment. At an intraosseous pressure of 14.3 (+/- 4.2) mmHg in the femoral head epiphysis (I), 11.6 (+/- 2.7) mmHg in the greater trochanter (II) and 9.3 (+/- 3.2) mmHg in the femoral shaft (III), a baseline flow of 96.2 (+/- 18.8, n = 12) ml/min was measured in the femoral vein. After infusing bradykinin at a concentration of 10(-6) moles, which is commonly known to lead to cerebral and subcutaneous oedema formation by vessel dilatation, the intraosseous pressure increased to (I): 49.1 (+/- 6.2) mmHg, (II): 42.5 (+/- 5.8) mmHg and (III): 38.3 (+/- 7.1) mmHg in the three measured femoral areas (n = 3). After the bradykinin injection, femoral vein flow increased to a peak value of 238.4 (+/- 43.4) ml/min and then dropped to 62.3 (+/- 14.2) ml/min after discontinuation of the bradykinin infusion. In a second and third series of tests, hyperosmolar (20% NaCl) and hypo-osmolar (distilled water) solutions were applied, also resulting in increased but lower mean intraosseous pressure values (17.3 +/- 4.1 and 25.7 +/- 5.1 ml/min, respectively) in all regions. When administering bradykinin, MRI scans taken immediately after completion of the experiment showed substantial oedema in the femoral muscular system, but without any changes of osseous signals in T1- or short time inversion recovery (STIR)-weighted images, nor did any changes occur when solutions of 20% NaCl or distilled H2O were injected. The results of our experiments demonstrate that acute increases of intraosseous pressure do not cause MRI signal alterations. We therefore conclude that in addition to the described pressure increase, other intraosseous alterations must occur to lead to the detectable signal changes found among patients with diagnosed femoral head necrosis. Finally, the short time period between the rise in intraosseous pressure and performing a conventional MRI may be one reason for missing the development of an intraosseous oedema. On the other hand, conventional MRI might have additional disadvantages for detecting intraosseous fluid compared with a dynamic imaging modality.

[Effect of bradykinin on pressure changes in the femur head epiphysis--an experimental and magnetic resonance tomography study]

AIM OF THE STUDY

The aim of this study was to evaluate the response of the femoral head to intraosseous pressure increases and to document blood flow of periarticular soft tissue after infusion of vasoactive substances. Beside that the value and imagery of native MRI after induced intraosseous pressure increase should be estimated for early detection of femoral head necrosis.

METHODS

The alteration of intraosseous pressure and peripheral blood flow of the femoral head of beagle dogs was examined after administration of bradykinin as a vasoactive substance followed by subsequent magnetic resonance imaging (MRI). Bradykinin was injected into the arteriae circumflexae femoris lateralis and medialis of six beagle dogs. The administrations were made using a standard protocol with simultaneous measurement of venous blood flow and intraosseous pressure distribution in the epiphysis of the femoral head. Bradykinin was applied in regular time intervals followed by MRI.

RESULTS

At a mean epiphyseal pressure 14.66 mmHg (sigma: 2.42) in the femoral head, a mean flow of 91.6 ml/min (sigma: 16.08) was measured in the vena femoralis. After an administration of a defined concentration of bradykinin an increased epiphyseal pressure was recorded in the measured area. An average increase blood flow of the vena femoralis was observed at the beginning of the bradykinin-injection, followed by a circulatory volume reduction. The post-experimental MRIs showed massive oedema in the femoral musculature after bradykinin-application, however without osseous signal alterations in T1- or STIR-weighted images.

CONCLUSION AND CLINICAL RELEVANCE

Our results indicate that acute intraosseous pressure increases are not accompanied by signal alterations in MRI. Obviously more extensive pressure induced lesions are necessary for detectable signal alterations, as these have already been demonstrated in patients with diagnosed femoral head necrosis.

[Reperfusion capacity of the femur head after ischemia--an experimental study]

PURPOSE OF THE STUDY

The aim of this study was to evaluate bone blood flow of the proximal femur during experimentally induced ischemia and to document the ability of epiphyseal and metaphyseal reperfusion.

METHODS

11 pigs (danish landrace) were used to investigate the effect of tamponade by increased joint pressure (Dextran 70) on the perfusion of the femoral head. Additional 8 pigs were used as control. The blood flow in the hip joint was studied by means of the microsphere technique. The flow was determined before, during and after intraarticular pressure increase. With the "radioactive tracer microsphere"-method the blood flow of the epiphysis, metaphysis and proximal femoral corticalis could be measured.

RESULTS

In the epiphyseal femoral head the initial blood flow rate, 11.7 ml/min/100 g, was not significant different from that of the control side (11.1 ml/min/100 g). The blood flow decreased in the ischemic phase to 1.8 ml/min/100 g followed by reperfusion to 13.5 ml/min/100 g (p < 0.01). The bone blood flow of reperfusion was not significant different from that of the initial blood flow rate but in 2 cases a "blow out" of the epiphyseal bone blood flow was seen. The proximal femoral metaphysis showed the highest of the measured intraosseous flow rates (17.9 resp. 23.3 ml/min/100 g). During ischemia and reperfusion of the epiphysis bone blood flow of the metaphysis remained the same. The proximal femoral corticalis showed the lowest of the measured intraosseous flow rates. The operated (10.1 ml/min/100 g) and contralateral hip side (11.7 ml/min/100 g) showed no significant differences in the initial blood flow rate. During ischemia and reperfusion the blood flow of the proximal corticalis showed no significant difference to the initial blood flow corresponding to the metaphysis.

CONCLUSIONS

Our study demonstrates disturbances of the circulation of different regions of the femoral head during intraarticular pressure increase and following pressure decrease of the growing pig. 2 "blow outs" document a vulnerable proximal epiphysis already after a 6-hour ischemia. Additional minor "bone quality" in cases of certain diseases (kidney transplantation, leukemia) and special administration of drugs (corticosteroids) seem to create an additional vulnerability of the proximal femoral head. The experiment proves to be a reliable model for decreasing the blood flow of the growing epiphysis temporarily and to document the beginning of normal reperfusion. With this model it is possible to examine the vulnerability of the epiphyseal perfusion after different diseases and under the influence of different medication.

[Late arterial complications after radiotherapy]

Late effects of radiotherapy are observed more frequently due to the improved results of the treatment of cancer and the resulting longer survival times. The big arteries, however, are only seldom attacked by late complications. The authors present a single case and stress the importance corresponding therapeutic action.