Design and methods of a randomized web-based physical activity intervention among children with cancer: A report from the Children's Oncology Group

BACKGROUND

Promoting physical activity soon after treatment for childhood cancer may benefit health because sedentary lifestyle during curative therapy may perpetuate physical and emotional complications. The primary goals of this study are to evaluate the effects of a 6-month web-based, rewards-based physical activity intervention on fitness, biomarkers of cardiometabolic health, inflammation, adipokine status, quality of life and school attendance, and determine if effect of intervention on markers of cardiometabolic health is mediated by changes in fitness. The primary outcome of interest is fitness (physiological cost index, six-minute walk test) measured at end of intervention.

METHODS

This ongoing study is a two-arm, prospective, randomized design with accrual goals of 192 children for intervention and control groups. Children ≥8 years and < 16 years of age, not meeting recommended levels of physical activity, who completed therapy within the past 12 months are eligible. Both groups receive: 1) educational materials encouraging physical activity, 2) activity monitor, 3) access to web-based interface designed to motivate physical activity, 4) rewards based on physical activity levels, and 5) access to their activity data on the web-interface. Those randomized to intervention: 1) can view others' activity and interact with other participants, and 2) receive rewards based on physical activity levels throughout the intervention (vs. at the end of the intervention for control group).

CONCLUSION

Unique, scalable, and portable physical activity interventions that motivate young survivors are needed. This study will inform future web-based physical activity interventions for children with cancer by demonstrating effects of rewards and social interaction.

CLINICAL TRIALS

ClinicalTrials.gov Identifier: NCT03223753; COG Identifier: ALTE1631.

Genomic answers for children: Dynamic analyses of >1000 pediatric rare disease genomes

PURPOSE

This study aimed to provide comprehensive diagnostic and candidate analyses in a pediatric rare disease cohort through the Genomic Answers for Kids program.

METHODS

Extensive analyses of 960 families with suspected genetic disorders included short-read exome sequencing and short-read genome sequencing (srGS); PacBio HiFi long-read genome sequencing (HiFi-GS); variant calling for single nucleotide variants (SNV), structural variant (SV), and repeat variants; and machine-learning variant prioritization. Structured phenotypes, prioritized variants, and pedigrees were stored in PhenoTips database, with data sharing through controlled access the database of Genotypes and Phenotypes.

RESULTS

Diagnostic rates ranged from 11% in patients with prior negative genetic testing to 34.5% in naive patients. Incorporating SVs from genome sequencing added up to 13% of new diagnoses in previously unsolved cases. HiFi-GS yielded increased discovery rate with >4-fold more rare coding SVs compared with srGS. Variants and genes of unknown significance remain the most common finding (58% of nondiagnostic cases).

CONCLUSION

Computational prioritization is efficient for diagnostic SNVs. Thorough identification of non-SNVs remains challenging and is partly mitigated using HiFi-GS sequencing. Importantly, community research is supported by sharing real-time data to accelerate gene validation and by providing HiFi variant (SNV/SV) resources from >1000 human alleles to facilitate implementation of new sequencing platforms for rare disease diagnoses.

Extension Horses, Inc. experts act fast to create online resources to assist the horse industry during COVID-19

The COVID-19 pandemic and resulting stay-at-home directives, adopted out of necessity to protect human health, introduced significant challenges for horse owners and small equine businesses. Restricted access, and in many cases closure of barns, resulted in a multitude of questions and concerns within the equine community which needed to be addressed rapidly. Extension Horses, Inc. (EH) coordinated the development and delivery of a variety of educational resources utilizing a combination of online formats and dissemination through social media and EH member contact lists. A series of infographics, webinars, and podcasts (three in each category) were created to provide guidance on essential care of horses, emergency preparedness, financial assistance, legal concerns, and biosecurity during the crucial, initial weeks of the pandemic (March to April 2020). Web conferencing technology (Zoom) was used to facilitate discussion and task delegation among EH members and to conduct and record webinars and podcasts. Podcasts were hosted on Buzzsprout and infographics were created using Adobe InDesign. Live webinar participants were invited to participate in several polls during the webinar and were sent a brief survey to complete at the end of the webinar series. Analytics for all educational resources combined demonstrated a 32-d total direct reach of 135,563. Most live webinar participants identified themselves as horse owners and small equine business owners (55%). The majority of live webinar participants indicated the information was useful (99%), and they would utilize the resources they had learned about (80%). Survey respondents reported that Facebook, email, and word of mouth were key ways in which they learned about the webinars. The same survey found that the web-platform was an effective method to receive information (85% high satisfaction) and respondents were highly likely to recommend future EH webinars to others (88%). The three infographics had a total Facebook reach of 131,765, the webinars had 3,522 total views, and the three podcasts had 276 total downloads. The rapid response of EH and quick turnaround of products allowed a large online audience to receive vital information for coping with COVID-19. Having the established EH network, already familiar with virtual education, was a big asset in this effort. This can serve as a model for cooperative extension to utilize in future collaborative responses to industry issues.

Analysis of psychosocial distress screening and needs assessment in adult survivors of childhood cancer

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Background: Childhood cancer survivors (CCS) face complex psychological late effects. The need for systematic screening for psychosocial distress has been clearly identified; however, less clarity exists around characterizing factors that might identify patients at higher risk to support targeted treatment. The purpose of this study was to examine the results of psychological screening in a clinic for adult survivors of childhood cancer using the validated NCCN Distress Screening Thermometer and modified Needs Assessment and exploring the results with other patient factors. Methods: Retrospective chart review was completed on 117 CCS seen in our Survivorship Transition Clinic (STC) between 2014 and 2017. The NCCN Distress Thermometer and Needs Assessment were administered to patients attending the STC. Results were then analyzed with a number of additional factors to explore association. These factors included intensity of treatment (by Children’s Hospital of Philadelphia Intensity of Treatment Rating scale or ITR3), gender, and age at diagnosis. Results: Of 117 patients, 54 had low intensity ITR3 scores (1 or2) and 63 had high intensity ITR3 scores (3 or 4). Mean distress score was 2.669 for the group. A weak but statistically significant association existed between ITR3 scores and distress scale scores (r = 0.2, n = 117, p = 0.022). Mean distress scale scores did not differ between men (2.26 +/- 2.09) and women (2.92 +/- 2.6) nor were they significantly related to age at diagnosis (p = 0.242). Needs assessment identified emotional, nutritional, and physical as the most frequent concerns. Care needs mostly commonly identified were feeling anxious/worried/irritable, being concerned with weight control, or problems with pain / fatigue. Conclusions: While we did not identify statistically significant differences in distress based on gender or age at diagnosis, we did find weak statistical association between higher treatment intensity and higher distress scores. Needs assessment helped guide care plan development. As childhood cancer survivor rates increase, we have an obligation to evolve our understanding of not only physical late effects but also psychological late effects.

Primary and subspecialty care trends for adults with a history of childhood cancer

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Background: With growing numbers of childhood cancer survivors (CCS), having systems for survivorship care coordination is imperative. While studies have compared the comfort and knowledge between primary care and oncology physicians in providing CCS care, few have analyzed primary and subspecialty care rates. Referral trends can be informative for institutions developing systems of care. Correlative measures with referral needs may help institutions prioritize process development for patients. Methods: Retrospective chart reviews were completed on 117 adult CCS from Survivorship Transition Clinic (STC) between 2014-2017. Upon arrival, STC patient self-reports were recorded regarding existing PCP status. Patients with PCPs were enrolled in survivorship consultation care, those without enrolled in survivorship and PCP care. Referrals were tracked by electronic medical record. Two oncology providers performed blinded independent reviews treatment summaries and scored treatments using Children’s Hospital of Philadelphia Intensity of Treatment Rating scale (ITR-3). If scores differed, discussion determined consensus. Final scores were matched with data on subspecialty referral patterns. Results: Of 117 patients, 65 (57%) needed both PCP and survivorship care while 50 (43%) had established PCPs. ITR3 scores were low intensity (1 or2) for 54 patients and high intensity (3 or 4) for 63 patients. The low intensity group had 157 total referrals (3 per patient) compared to 391 total referrals (6 per patient) in the high intensity group. The top 5 subspecialty referrals (by patients referred) were psychological services (46), dermatology (44), fertility (29), hematology / oncology / BMT (22), cardiology (20). Conclusions: Our care coordination trends suggest many CCS do not have established PCPs despite their complex care needs. Not surprisingly, higher intensity treatment correlates with higher subspecialty care needs. Psychological care remains the most prevalent need in our patient population. [Table: see text]

Successful Use of eXtension and Online Training Modules in Mandatory Biennial Volunteer Recertification

Quality volunteers are essential to the success of 4-H programs. Although much attention has been paid to the initial orientation of volunteers, additional training is typically optional. Beginning in 2013, our county required all adult volunteers to complete at least one hour of continuing education as part of a biennial recertification process. We used existing resources (“eLearning for Volunteer Orientation”; eXtension webinars).  There was no significant difference in volunteer retention between re-screening and non-re-screening cohorts (p=.855). We collected 166 volunteer ratings of 23 recorded webinars on eXtension. Volunteers gave concrete examples of how they would use the information learned in their volunteer role.

Rationale and design of the Children's Oncology Group (COG) study ALTE1621: a randomized, placebo-controlled trial to determine if low-dose carvedilol can prevent anthracycline-related left ventricular remodeling in childhood cancer survivors at high risk for developing heart failure

BACKGROUND

Anthracyclines are widely used in the treatment of childhood cancer. One of the well-recognized side-effects of anthracycline therapy is dose-dependent cardiomyopathy that may progress to heart failure (HF) years after completion of cancer-directed therapy. This study will evaluate the efficacy of low-dose beta-blocker (carvedilol) for HF risk reduction in childhood cancer survivors at highest risk for HF. The proposed intervention has the potential to significantly reduce chronic cardiac injury via interruption of neurohormonal systems responsible for left ventricular (LV) remodeling, resulting in improved cardiac function and decreased risk of HF. The intervention is informed by previous studies demonstrating efficacy in pediatric and adult non-oncology populations, yet remains unstudied in the pediatric oncology population.

METHODS/DESIGN

The primary objective of the trial is to determine impact of the intervention on echocardiographic markers of cardiac remodeling and HF risk, including: LV wall thickness/ dimension ratio (LVWT/D; primary endpoint), as well as LV ejection fraction, volume, and blood biomarkers (natriuretic peptides, galectin-3) associated with HF risk. Secondary objectives are to establish safety and tolerability of the 2-year course of carvedilol using: 1) objective measures: hepatic and cardiovascular toxicity, treatment adherence, and 2) subjective measures: participant self-reported outcomes. Two hundred and fifty survivors of childhood cancer (diagnosed <21 years of age), and previously treated with high-dose (≥300 mg/m2) anthracyclines will be enrolled in a randomized, double-blind, placebo controlled trial. After baseline assessments, participants will be randomized in a 1:1 ratio to low-dose carvedilol (maximum dose: 12.5 mg/day) or placebo. Carvedilol or placebo is up-titrated (starting dose: 3.125 mg/day) according to tolerability.

DISCUSSION

When completed, this study will provide much-needed information regarding a physiologically plausible pharmacological risk-reduction strategy for childhood cancer survivors at high risk for developing anthracycline-related HF.

TRIAL REGISTRATION

ClinicalTrials.gov; NCT02717507.

[Recurrent failed ICD therapy of ventricular tachycardia]

Implantable cardioverter defibrillators (ICD) are used as standard therapy to prevent sudden cardiac death in heart failure patients. Today, physicians in emergency and intensive care medicine are often confronted with problems of ICD therapy in these patients. We report a case of a patient suffering from recurrent ventricular tachycardia (VT) requiring antiarrhythmia treatment with amiodarone. With an increasing drug loading, the VT cycle length was progressively prolonged resulting in a slow VT undetectable for the ICD. Subsequently, the patient was scheduled for VT ablation after which the patient became free of arrhythmia recurrences.

Nanocrystalline hydroxyapatite for bone repair: an animal study

Abstract Hydroxyapatite has become the most common material to replace bone or to guide its regeneration. Nanocrystalline hydroxyapatite suspension had been introduced in the clinical use recently under the assumption that small dimension of crystals could improve resorption. We studied the resorption and osteointegration of the nanocrystalline hydroxyapatite Ostim in a rabbit model. The material was implanted either alone or in combination with autogenic or allogenic bone into distal rabbit femora. After survival time of 2, 4, 6, 8 and 12 weeks the implants had been evaluated by light and electron microscopy. We observed a direct bone contact as well as inclusion into soft tissue. But we could observe no or only marginal decay and no remarkable resorption in the vast majority of implants. In situ the nanocrystalline material mostly formed densely packed agglomerates which were preserved once included in bone or connective tissue. A serious side effect was the initiation of osteolysis in the femora far from the implantation site causing extended defects in the cortical bone.

[Dynamic gait analysis of blocked distal tibiofibular joint following syndesmotic complex lesions]

AIM

Dynamic gait analysis of blocked distal tibiofibular joint (TFJ) has not performed yet. This prospective study investigated patients treated for ankle fractures with combined syndesmotic complex lesions after surgery including tibiofibular positioning screw using CT data detecting fibular maltorsion and dynamic gait analysis.

METHOD

Prepublished data of 61 patients after surgical block of TFJ were analysed for torsional deformity of the distal fibula with an especially developed novel CT method. 10 of these patients were selected for dynamic pedography (emed-SF4, Novel GmbH, Munich). The measurements were accomplished one and six weeks (with blocked TFJ) and four months (with deblocked TFJ) postoperatively.

RESULTS

The gait pattern of 10 pedographically investigated patients showed increased loads of the hindfoot as well as a load shift to the lateral midfoot. Four months postoperative significant differences of the plantar pressure pattern concerning the parameters force, pressure, impulse and contact time were not observed. The analysis of the foot progression angle (fpa) of the non operated feet demonstrated external rotation of 9,5 degrees in average. In comparison to the healthy side with tibiofibular positioning screw the operated feet were significantly internal rotated during the first two measurements. Patients with fibular torsional differences > 15 degrees showed not only with tibiofibular positioning screw but also after its removal a persistent difference of fpa in average of 5,6 degrees without external rotating retraction.

CONCLUSIONS

The temporary blockage of TFJ results into an altered pattern of dynamic plantar pressure distribution. A constant foot progression angle in relative internal rotation is registered. After removal of the positioning screw the recovered ligamentous structures allow retraction to the anatomic position. But, concerning fibular torsional differences > 15 degrees osseous fixation leads to alterated fpa presented as diminished external rotation of the foot of the formerly fractured ankle with consecutive dysfunction of the physiologic kinematic of movement and eventual provocation of posttraumatic arthritis.

AIM

Dynamic gait analysis of a blocked distal tibiofibular joint (TFJ) has not been performed yet. This prospective study investigated patients treated for ankle fractures with combined syndesmotic complex lesions after surgery including a tibiofibular positioning screw using CT data for detecting fibular maltorsion and dynamic gait analysis.

METHOD

Prepublished data of 61 patients after surgical block of TFJ were analysed for torsional deformity of the distal fibula with an especially developed novel CT method. Ten of these patients were selected for dynamic pedography (emed-SF4, Novel GmbH, Munich). The measurements were accomplished one and six weeks (with blocked TFJ) and four months (with deblocked TFJ) postoperatively.

RESULTS

The gait patterns of 10 pedographically investigated patients showed increased loads of the hindfoot as well as a load shift to the lateral midfoot. Four months postoperative significant differences of the plantar pressure pattern concerning the parameters force, pressure, impulse and contact time were not observed. The analysis of the foot progression angle (fpa) of the non-operated feet demonstrated external rotation of 9,5 degrees in average. In comparison to the healthy side the operated feet with tibiofibular positioning screw were significantly internally rotated during the first two measurements. Patients with fibular torsional differences > 15 degrees showed not only with the tibiofibular positioning screw but also after its removal a persistent difference of fpa in average of 5.6 degrees without external rotating retraction.

CONCLUSIONS

The temporary blockage of the TFJ results into an altered pattern of dynamic plantar pressure distribution. A constant foot progression angle in relative internal rotation is registered. After removal of the positioning screw the recovered ligamentous structures allow retraction to the anatomic position. But, concerning fibular torsional differences > 15 degrees osseous fixation leads to alterated fpa presented as diminished external rotation of the foot of the formerly fractured ankle with consecutive dysfunction of the physiologic kinematic of movement and eventual provocation of posttraumatic arthritis.

Pre-emptive intra-articular administration of local anaesthetics/opiates versus postoperative local anaesthetics/opiates or local anaesthetics in arthroscopic surgery of the knee joint: a prospective randomized trial

AIM

Arthroscopic surgery on the knee joint is increasingly being performed as day-case surgery. This necessitates adequate postoperative pain therapy. We performed a study to compare three different intra-articular regimens of pain treatment. The hypothesis was that preoperative intra-articular pain management is superior to postoperative procedures.

METHOD

In this study we compared the preoperative administration of 0.1 mg fentanyl + 5 ml bupivacaine 0.5% with the postoperative administration of either 0.1 mg fentanyl + 5 ml bupivacaine 0.5% or 5 ml bupivacaine 0.5% alone in a total of 564 patients. Participants were randomly assigned to three groups. Each group was subdivided into patients with and without synovitis.

RESULTS

The preoperative administration of fentanyl and bupivacaine significantly decreased the perceived pain. The efficiency increased with major arthroscopic procedures. Postoperative administration of bupivacaine alone had the least effect. There was variation within each group depending on whether synovitis was present or not.

CONCLUSION

This study demonstrated the superiority of the preoperative intra-articular administration of a combination of fentanyl and local anaesthetic over postoperative fentanyl and local anaesthetic or postoperative local anaesthetic alone.

Experience with the Mayo conservative hip system

PURPOSE OF THE STUDY

In the development of cementless total hip arthroplasty wear, loosening as well as stress shielding are considered as major issues. New results in literature specify survivorship of THA over 97%. Consequently the implant loosening and wear especially can be considered as almost solved. Therefore, it is essential to use bone preserving primary implants that allow for a physiological load transfer and cause no or only slight stress shielding at the proximal femur. The MAYO conservative hip stem with a wedge design ensuring immediate primary fixation of the stem with metaphyseal load transfer.

MATERIAL AND METHODS

A retrospective study was performed to review the first consecutive 316 MAYO conservative hip stems implanted at the Martin-Luther-University of Halle-Wittenberg (Germany). 85.4% (270 MAYO stems) were radiographic analysed and classified according to the HHS.

RESULTS

The mean HHS improved from 44.79 preoperatively to 93.58 postoperatively. 1.85% (5 MAYO stems) had to be replaced because of aseptic loosening. Furthermore the DEXA scans revealed the metaphyseal load transfer with increased bone density in the calcar region.

CONCLUSION

As especially younger patients will require one or more hip revision procedures during the course of their life due to their life due to their age and activity level. These patients should receive a primary implant with proximal load transfer. Only these implants can avoid stress shielding of the proximal femur. The minimally invasive implantation of these implants can also ensure an enhanced periprosthetic bone density an optimized postoperative rehabilitation phase.

[Radiological mid-term results of total knee arthroplasty with femoral components of different materials]

AIM

The present work aimed at evaluating the radiological mid-term results of femoral components of different materials in an identically designed total knee system.

METHOD

31 knees with zirconium femoral components and 32 standard femoral components were evaluated about 4 years following surgery using the Roentgenographic Evaluation and Scoring System of the Knee Society.

RESULTS

In both groups, the implant position was correct. There was a statistically significant higher rate of radiolucent lines in zones 1 and 4 at the tibia site in the zirconium group.

CONCLUSION

Our clinical results disagree with the results of biomechanical studies of the same type of prosthesis. However, there are some findings from animal studies showing that zirconium ions may inhibit the mineralisation of osteoid, which could be an explanation for the higher rate of radiolucent lines seen in the present study.

[Influence of the surgical approach on postoperative rehabilitation after TKA]

BACKGROUND

Minimising the soft tissue trauma and early rehabilitation are among the major aims using the MIS technique in joint replacement.

AIM

The aim of this prospective randomised study is to compare the results after TKA using an MIS approach versus a standard approach.

METHOD

We compared 30 TKA using a mini-midvastus approach (MIS group) with 30 conventionelly performed TKA using a midvastus approach (control group). In all cases the same implants (NexGen LPS) were used. The Knee Society score (KSS), an activity score, the visual analogue scale, myoglobin and creatinine kinase as well as the blood loss were measured up to 12 weeks postoperatively. Implant positioning was evaluated using the Knee Society Roentgenographic evaluation and scoring system.

RESULTS

Advantages of the MIS group were measured in KSS and activity score up to 12 weeks postoperatively. The increase of myoglobin and creatinine kinase was lower in the MIS group up to 24 hours or 72 hours, respectively. No differences were found comparing the implant positioning and blood loss.

CONCLUSION

The MIS technique in TKA with minimisation of the soft tissue trauma leads to better clinical and functional results in the early postoperative time and does not modify the implant positioning.

[Comparison of anterior lumbar fusion rates after circumferential fusion using beta-tricalcium phosphate (Cerasorb) versus autologous iliac crest spongiosa]

AIM

The aim of this prospective clinical trial was to analyse the ventral fusion rate following circumferential fusion for degenerative spine disease using a radiolucent carbon fibre cage (Brantigan, Fa. DePuy-Acromed) loaded with either autogeneous bone graft (iliac crest) or with the tricalcium phosphate Cerasorb with PRP (Curasan AG, Kleinostheim, Deutschland).

METHODS

In 26 patients (15 female, 11 male, average age: 57.7 years) a circumferential fusion of the lumbar spine was performed (titanium posterior instrumentation and Brantigan, Fa. DePuy-Acromed). Autogeneous bone graft (iliac crest) and Cerasorb-PRP as cage filling substance were randomly assigned to each level in all patients. Anterior fusion was evaluated in a total number of 69 Brantigan cages by radiographs after 3, 6, 9 and 12 months and by CT 1 year after surgery.

RESULTS

The evaluation of radiographs resulted in a fusion rate 49 %. This was significantly different from the fusion rate accessed by CT scanning (28 %). None of the Brantigan cages (n = 33) filled with Cerasorb with PRP showed an anterior fusion in the CT while fusion was proven in 19 of 36 (49 %) Brantigan cages loaded with cancellous bone from the iliac crest.

CONCLUSION

The use a of cancellous bone from the iliac crest as filling substance for Brantigan cages in circumferential fusion of the lumbar spine leads to a significantly higher anterior fusion rate than Cerasorb with PRP.

[Cage failure following replacement of the third lumbar vertebral body in Hodgkin's disease]

AIM

We present a case report and the histological analysis of cage failure following vertebral body replacement in Hodgkin's disease.

METHOD

In a 35-year-old patient with a single metastasis of Hodgkin's disease replacement of the third lumbar vertebral body (Harms-titanium-mesh-cage, DePuy Acromed, completely filled with autogenous spongiosa from the iliac crest) was performed. 51 months postoperatively, the patient presented with acute back pain without trauma. The X-ray showed a collapse of the Harms-titanium-mesh-cage. The cage fragments had caused ventral dislocation of the main blood vessels and dura compression without neurological deficits. After the replacement of the failed Harms-cage (Synex, Synthes) histological analysis (light microscope, non-decalcified horizontal cuts, thickness of 150-200 microm, Giemsa und van Gieson staining) was done.

RESULT

The histology showed a remodelling of new bone in the area of the endplates without contact to the cage wall. In the region of the cage corpus, bony necrosis and connective tissue rich in cells was found.

CONCLUSION

Bridging fusion in vertebral body replacement cages is not proven. As a result cage failure may occur. Therefore, in tumour patients with high live expectancy, Palacos filling of the cages should be discussed.

The influence of lidocaine and verapamil on the proliferation, CD44 expression and apoptosis behavior of human chondrocytes

Ion channels, which are responsible for the controlled functioning of many cell biological processes, are present on the cell membrane of all living human cell systems under physiological conditions. A relationship between ion channel activity and proliferation behavior has been demonstrated in various cell systems. We showed in earlier studies that there is a resting membrane potential in the cell membranes of human chondrocytes, which can be influenced by various ion channel modulators. The question is to what extent can specific modulation of the ion channel activity regulate proliferation, CD44 expression and the apoptosis behavior of human chondrocytes. Human chondrocytes were isolated from osteoarthritic knee joint cartilage. The culture was made as a monolayer in RPMI medium with the addition of 10% fetal calf serum, 50 microg/ml gentamycinsulfate and 2 microg/ml amphotericin B at 37 degrees C and 5% carbon dioxide. The voltage dependent Na+ channel blocker, lidocaine, and the calcium antagonist, verapamil, were used as ion channel modulators. Proliferation was determined using 3H-thymidine incorporation as the measure. Proof of the CD44 membrane protein was performed by flow cytometry with an FITC-conjugated CD44 antibody (anti-CD44H-FITC). For apoptosis detection, the translocation of phosphatidylserine (Annexin V-FITC assay), Apo2.7 and the Caspase activity on cytokeratin 18 were determined by flow cytometry. The results show that proliferation behavior can be regulated by lidocaine and verapamil, whereby lidocaine results in a transient increase in 3H-thymidine incorporation. Both substances resulted in marked suppression of proliferation after longer incubation times. At the same time, no influence of lidocaine could be determined on the apoptosis of human chondrocytes, whereas marked cytotoxic effects occurred under verapamil. With respect to CD44 receptor expression, incubation with lidocaine resulted in an increase of up to 43%, while suppression of up to 56% was observed with verapamil. The possibility of specific modulation of ion channel activity on the cell membrane of human chondrocytes may serve as the basis for development of new therapeutic options for the treatment of arthrosis.

[Osteoporosis--a neglected issue in orthopaedics? Results of a survey amongst German orthopaedic surgeons]

AIM

Patients with fragility fractures have a significantly increased risk of sustaining additional fractures. Therefore one should consider avoidance of further fractures as the primary treatment principle. Since orthopaedic surgeons manage most of fragility fractures, but might not be well attuned to osteoporosis itself, it was the aim of the Bone and Joint Decade (BJD) and the International Osteoporosis Foundation (IOF) to survey orthopaedic surgeons in order to assess their knowledge of prevention, diagnosis, and treatment of osteoporosis.

MATERIAL AND METHODS

The multinational survey questionnaire was developed by a working group of national project co-ordinators in France, Germany, Italy, Spain, the United Kingdom, and New Zealand and based to some extent on an American survey. Following translation into the national language it was distributed in 2002 to the members of the orthopaedic societies to assess the management of prevention, diagnosis, and therapy of osteoporosis and fragility fractures, comparing both different health-care systems and different working environments. 5 700 questionnaires were distributed in Germany with a 20 percent response rate.

RESULTS

As the main result of the German survey -- independent of the working environment -- a substantial deficit concerning training and knowledge about the management of prevention, diagnosis, and treatment of osteoporosis and fragility fractures was seen. In addition, the majority of participants requested educational opportunities to become qualified for a better disease control.

CONCLUSION

In order to satisfy the increasing need for adequate management of prevention, diagnosis, and therapy of osteoporosis and fragility fractures, structured educational opportunities have to be offered to the German orthopaedic community. In the mean time first steps have been initiated: training courses to qualify as "Osteologe DVO" and the "White Book Osteoporosis", which was initiated by BJD and IOF and developed by several German medical societies and patient organisations it is based on the German DVO guidelines providing an evidence-based and structured overview concerning all relevant aspects of osteoporosis and fragility fractures.

[Does the NexGen LPS flex mobile knee prosthesis offer advantages compared to the NexGen LPS?--a comparison of clinical and radiological results]

Under experimental conditions, mobile bearing knee prostheses have several advantages. The optimized congruence of the tibio-femoral joint surface allows a knee flexion of more than 120 degrees without creating instability or increase of wear.

AIM

The aim of this study is to compare the results of a prospective randomized study after implantation of the mobile bearing knee prosthesis NexGen LPS Flex with the results of the fixed bearing knee prosthesis NexGen LPS.

METHODS

Sixty patients underwent a total knee replacement (30 patients with NexGen LPS Flex mobile, 30 patients with NexGen LPS) via a mid vastus approach. All implants were cemented (Palacos) including the patella resurfacing. We evaluated the Hospital for Special Surgery Score (HSS) and different radiological parameters (maximal flexion, positioning of the implants, leg axis) preoperatively as well as 3 months and 3 years (34.6 +/- 7.3 months) postoperatively.

RESULTS

After 3 months the NexGen LPS Flex group showed better results in the scores for pain, range of motion (122.5 degrees vs. 107.33 degrees ) as well as the overall HSS (87.21 vs. 82.68 points) compared to the NexGen LPS group. Three years postoperatively there were no differences in all scores between the two groups.

CONCLUSION

The theoretical advantages of the mobile bearing knee prostheses were reflected in the clinical results only partly and temporarily. Probably the results of long-term follow-ups will show characteristic advantages or disadvantages of mobile bearing knee prostheses.

[Axial load in case of press-fit fixation of the ACL graft--a fundamental study]

AIM

The aim of this study was the determination of the axial fixation load resting on smooth press-fit dowels needed for fixation of the patellar tendon graft (BTB) in order to reach the same fixation properties compared to the interference screw on anterior cruciate ligament (ACL) plasty.

METHOD

Bovine test specimens with 27 BTB grafts fixed in tibial drill holes were used and divided in 3 groups: interference screw, and press-fit cylinder (Ø 7 mm) with 150 N and 100 N axial loads. Prior to fixation, impactation of the transplant into bone was carried out. Failure testing was done in a tensiometer at a cross-head speed of 50 mm/min. Determinations of peak load and stiffness were also made.

RESULTS

Similar peak loads and stiffness were reached on introducing a press-fit dowel (slashed circle 7 mm) with 100 N and 150 N axial load compared to interference screw fixation of the BTB graft. Peak load: 988.1 N +/- 365.1 (screw) versus 1 210.4 N +/- 292.4 (dowel 150 N) and 1 109.8 N +/- 505.4 (dowel 100 N). Stiffness: 86.4 N/mm +/- 20.5 (screw) versus 102.4 N/mm +/- 15.2 (dowel 150 N) and 77.1 N/mm +/- 11.0 (dowel 100 N). There was no significant difference.

CONCLUSION

When introducing a press-fit dowel (slashed circle 7 mm) with 100 N axial load into a preformed bone bed, the same fixation properties are reached as in the case of an interference screw on BTB-ACL plasty.

[Wristing -- a new opportunity in digital migration analysis of uncemented total hip arthroplasty]

AIM

The aim of this study was to evaluate a computer program (Wristing) for digital migration analysis in hip endoprotheses and to assess the most accurate landmarks in hip-alone radiographs.

METHOD

Conventional radiographs of 52 patients with a minimum follow-up period of seven years and five consecutive radiographs were digitised and different landmarks were compared. The parameters with the greatest accuracy were analysed to calculate inter- and intra-observer variability in 30 radiographs. Digital and manual measurement techniques were compared with each other.

RESULTS

The obtained accuracy (95 % confidence interval) was 1.7 to 2.2 mm and 2.8 degrees to 3.2 degrees for the most accurate landmarks. The intra-observer variability was 0.12-0.3 mm; 0.28 degrees and the inter-observer variability ranged from 0.14 to 0.45 mm and 0.5 degrees to 0.53 degrees . In comparison to the migration measurement with pencil and ruler (precision: 0.24-0.67 mm; 0.57-0.74 degrees ) the new software (precision: 0.12-0.3 mm; 0.28 degrees ) was associated with a superior accuracy (t test: p < 0.001).

CONCLUSION

With the program "Wristing" migration in hip-alone radiographs could be recorded with high precision. The integrated sketch, zooming and the current possibility of comparing radiographs and patient data with previous follow-ups and examples leads to a high inter- and intra-observer accuracy and is very useful in day-to-day clinical practice.

[Advantages of minimal invasive total hip replacement in the early phase of rehabilitation]

In arthroplasty the term "minimal invasive" not only refers to the length of the skin incision but more so to its soft tissue and thereby muscle-protecting features.

STUDY AIM

The aim of this study is to compare the early postoperative mobilisation and rehabilitation of the different surgical approaches in cementless total hip arthroplasty.

METHODS

27 patients underwent a total hip replacement (Trilogy cup, MAYO stem) via a ventral minimal invasive approach (one incision technique) (MIS group). 23 patients underwent a total hip replacement with the same implant via a anterolateral transgluteal approach (standard group). We evaluated the Harris Hip Score (HHS), the visual analogue scale (VAS) for pain and patient satisfaction preoperatively as well as 3 days, 10 days, 6 weeks and 3 months postoperatively.

RESULTS

After 3 and 10 days the MIS group showed better scores for pain, gait and mobilisation as well as for the overall HHS compared to the standard group. These differences could not be shown 6 weeks postoperatively. The MIS group had a significantly higher rate of complications with 22 % transient impairment of the lateral cutaneous nerve.

CONCLUSION

The patients of the MIS group showed a better mobilisation and rehabilitation during the early postoperative period. This can be attributed to the lessened intraoperative damage of to soft tissue and especially muscle damage. Due to the increased rate of nerve irritations, we modified our surgical approach. The minimal invasive approach to modern hip joint arthroplasty remains a non-standard technique. Compared to the standard approach it carries additional risks (like nerve damage and malpositioning of the implants and thus should remain in the hands of the experienced orthopaedic surgeon in specialised orthopaedic centres.

Multimediale Patientenaufkl�rung in der Klinik

Due to heavy workloads and shortage of staff, doctors often find it difficult to explain operations to their patients with the legally required detail and timing (in Germany, 24 h preop). This is however mandatory for obtaining informed consent. We developed a computer program that generates films explaining 24 common orthopedic operations and blood transfusion. They explain the operation, early postoperative phase, and benefits and risks to the patient. At our clinic, this program is used in daily routine and precedes the actual doctor-patient conversation for informed consent. We asked 300 patients about their satisfaction with the newly developed program. The multimedia presentation gives the patient more time, enough detail and clarity, and the chance to repeat parts of the film. For the doctor, it saves time. The time gap required in Germany between explanation and operation is thus easily adhered to. In case of legal problems, the film can be used for evidence. The use of this multimedia presentation to help in getting informed consent is improving workflow considerably.

Erweiterter push out-Test zur Schädigungscharakterisierung der Implantat-Knochen-Grenzfläche / Extended push-out test to characterize the failure of bone-implant interface

To study the mechanical behaviour of the implant-bone interface the push- or pull-out test was overtaken from material science. Most authors equate the maximum load (break point) with the failure of the implant integration. Extending the test procedure by acoustic emission analysis reveals the possibility to detect the failure of the interface more in detail and from its earliest beginning. The development of disconnection between host and implant was found to start long before the ultimate load is reached and can be monitored and quantified during this period. The active interface mechanisms are characterized by the distribution function of acoustic emissions and the number of hits per time defines the kinetics of the failure. From clinical studies a gradual subsidence of loaded implants is known starting long time before the definite implant failure. The presented extension of the push-out test with acoustic emission analysis allows the detection of a critical shear stress tc which demarks the onset of the gradual interface failure. We believe this value to represent the real critical load which should not be exceeded in the clinical application of intraosseous implants.

Fr�hfunktionelle Ergebnisse einer Kurzschaftprothese des H�ftgelenks mit metaphys�r-intertrochant�rer Verankerung

Total hip arthroplasty has become one of the most successful standard procedures in orthopedic surgery. With a more frequent use in young and active patients bone saving procedures become more important. The goal is to save good bone stock for the revision procedure. One example of conservative femoral implants is the Mayo-stem with reported long term results. The stem design allows a metaphyseal intertrochanteric multipoint fixation for primary fixation. The surgical technique is simple. Using a transgluteal approach, the medial preparation of the femoral neck decreases significantly the irritation of the abductor tendons. In a prospective-randomized study, the early functional results with the Mayo-stem were significantly better than the results achieved with a cement-free standard stem. The Mayo-stem may not be indicated for every hip situation. Its use, however, in cases with normal anatomy contributes to save autologeous bone. Therefore, this short stem is a sensible alternative to standard stems.

Prevention of deep-vein thrombosis after total hip and knee replacement. Low-molecular-weight heparin in combination with intermittent pneumatic compression

After total hip (THR) or knee replacement (TKR), there is still an appreciable risk of developing deep-vein thrombosis despite prophylaxis with low-molecular-weight heparin (LMWH). In a prospective, randomised study we examined the efficacy of LMWH in combination with intermittent pneumatic compression in patients undergoing primary unilateral THR or TKR. We administered 40 mg of enoxaparin daily to 131 patients combined with either the use of intermittent pneumatic compression or the wearing of graduated compression stockings. Compression ultrasonography showed no evidence of thrombosis after LMWH and intermittent pneumatic compression. In the group with LMWH and compression stockings the prevalence of thrombosis was 28.6% (40% after TKR, 14% after THR). This difference was significant (p < 0.0001). In the early post-operative phase after THR and TKR, combined prophylaxis with LMWH and intermittent pneumatic compression is more effective than LMWH used with graduated compression stockings.

[Significance of lateral release in the therapy of patellar chondromalacia]

A retrospective study was performed in 26 patients who underwent an operation for femoro-patellar pain due to a patellar chondromalacia with or without minor patellar dislocation/lateral pressure syndrome. The average age of the patients was 28.5 (15-39) years. 22 of the 26 patients revealed minor chondral damages of the stages 1 and 2 according to Outerbridge. In 12 patients ("lavage" group), an arthroscopic joint debridement only was carried out, while an additional open, lateral retinaculum release was made in 14 patients ("lateral release" group). The patella's distance of dislocation according to Hepp was reduced on an average of 3.0 (0-7) mm (p = 0.0019). The results of Bentley's score obtained during the follow-up interval on an average of 30.1 (9 to 60) months were almost identical for both groups. "Good" and "very good" results were achieved in the "lavage" group (83.3 %) and "lateral release" group (78.6 % of the patients). Lateral release should be used in cases of patellar decentration between 5 and 10 mm and adequate pain symptoms. The post-operative distance of dislocation should be less than 5 mm. Under such conditions and with minor chondral damage, a combined approach by using an arthroscopic joint debridement and open lateral release is promising to treat a patellar dislocation/lateral pressure syndrome.

[Bone defects in revision total knee arthroplasty: classification and management]

The goal of bone reconstruction in revision total knee arthroplasty is to provide a stable support for the implant and to re-establish the correct joint line. Therefore, a useful, therapy-based classification of the defects is necessary. According to Stockley et al. (1992), the defects are classified into contained and uncontained defects. Uncontained defects can be reconstructed using structural allografts or metal wedges. In contained defects, cancellous allograft can be used. For aseptic loosening of total knee arthroplasty, the defect classification according to Engh and Parks (1994) can be helpful because of its recommendations for reconstruction. In case of the more common first or second graded defects, reconstruction is performed using modular revision components or allografts. For the rare third graded defects, bulk allografts or modular tumour endoprostheses are recommended. On the basis of more than 150 revision total knee arthroplasties performed in our hospital the classification of bone defects and their clinical consequences are presented in this review.

[Recurrence of Baker's cysts with regard to operation procedure and intraarticular pathology]

During the period from January 1990 to December 1998 65 patients were operated upon for a Baker's cyst. 41 patients (43 operations) were subjected to a clinical and sonographical follow-up examination and interrogation. In 11 cases, the cysts were merely removed, while an open synovectomy was carried out four times (rheumatics) in addition to the removal of the cysts, and arthroscopy with exstirpation was performed in 28 cases. The total recurrence rate was 14 % (6/43). Any significant differences between the groups were not found (p = 0.291). The overall complication rate was 18.6 %. In case of recurrence, the clinical results were significantly worse (p = 0.036). Apart from technical aspects of operation, the not quantifiable correlation between grade of chondromalacia and the formation of effusions following joint degeneration has to be discussed as a cause for recurrences. If both interventions are carried out in one course, there is no increased operative risk. Especially in cases with intraarticular pathological symptoms arthroscopy should precede each cyst exstirpation. With regard to the frequency of recurrence, the patients' expectation should be preoperatively objectified.

[DNA flow cytometry of bone metastases of different primary tumors]

AIM

Some human tumors of different primary localization metastasize preferably into the bone. This concerns especially kidney, breast, prostate and lung cancer. So far, the reason for this specific pattern of metastazing could not sufficiently be clarified. The aim of the study was the search for mutuality in the results of the DNA analysis of bone metastases of different primary tumors and their importance for prognosis and therapy.

METHOD

In this study, the DNA content of 40 excised bone metastases of different primary localisation has been determined by flow cytometry. By means of the DNA distribution pattern, the percentage of tumor cells in the particular cell cycle phase as well as the respective ploidy condition have been calculated.

RESULTS

Altogether, no preference of DNA diploid or DNA aneuploid stem cell lines could be found. Whether this can be applied for metastases of all primary tumors has not been clarified yet. The fact that, in 11 out of 12 tested cases of the same metastasis, DNA diploid as well as DNA aneuploid areas could be demonstrated, seems to be fundamental.

CONCLUSION

There exist a high variability of the extent of dysregulation and the intensity of the growth of bone metastasis. This does not seem to be crucial for the preferable tendency to metastazise into the bone. Due to the often insufficient tumor amount for material extraction from different areas and the large amount of DNA diploid metastases after flow cytometry analysis there should be considered the additional use of pictorial analytical methods for the DNA ploidy and proliferation assessment. A knowledge of the intensity of the course and the degree of dysregulation of tumor cell proliferation of bone metastases is beneficial in order to estimate the prognosis and to design an individual therapy regime.

Is the proliferation of human chondrocytes regulated by ionic channels?

As in cells in all living cell systems, human chondrocytes are provided with a membrane potential. The existence of ion channels in the cell membrane is an essential prerequisite for the development of membrane potential. In nonhuman chondrocytes, different ion channels have already been identified. An association between potassium channel activity and cell proliferation has been detected in different human cell systems, whereas proof of an association between ion channel activity in human chondrocytes and their proliferation has yet to be established. In this study, we investigated the concentration-dependent influence of the ion channel modulators tetraethylammonium (TEA), 4-aminopyridine (4-AP), 4',4'diisothiocyanato-stilbene-2,2'-disulfonic acid (DIDS), 4-acetamido-4'-isothiocyano-2,2'-disulfonic acid (SITS), and verapamil (vp) on the membrane potential and the proliferation of human chondrocytes, using flow cytometry. We found that the used ion channel modulators caused a change in the membrane potential of human chondrocytes. The membrane potential was decreased by 18% with 0.25 mmol/l vp (the maximal measurable effect of any of the ion channel modulators) compared with that in a control group. We measured DNA distribution in the human chondrocytes, and it was apparent that they were diploid cells with a very low proliferative tendency. These results allow us to conclude that ion channel modulators influence chondrocyte proliferation. Knowledge of the regulation of chondrocyte proliferation via ion channel modulators could serve in the research of new osteoarthritis treatment concepts.

Posteroplantar release for congenital clubfoot in children younger than 1 year

One hundred thirty-three resistant congenital clubfeet in 93 patients between 3 and 10 months of age were operated on using a standardized posteroplantar release. Clinical and radiographic assessments were done with a mean followup of 7 years 4 months (range, 3-12 years). Using the McKay score, 79.7% of the surgically treated clubfeet were classified as having a good or excellent result. Three patients had relapse of their clubfoot that required additional surgery. Seventeen feet in 15 patients had residual forefoot adduction at the time of followup. The radiographs showed that the early posteroplantar release led to sufficient hindfoot correction in all but the three patients who had relapse of the clubfoot. With this standardized surgical treatment, satisfactory results can be achieved in most patients younger than 1 year with congenital clubfoot. However, in patients with persistent talonavicular subluxation after conservative treatment, an additional talonavicular release combined with the posteroplantar release is recommended.

[Early results of a prospective study in patients with computer-assisted femur shaft preparation in total hip endoprosthesis implantation (Robodoc system)--indications, outcome, complications]

AIM

Indications, results, advantages and disadvantages of the computer-guided femoral preparation in total hip arthroplasty (Robodoc) in our patients are recorded and represented.

METHOD

41 patients who underwent a computer-guided femoral preparation in total hip arthroplasty (Robodoc) were examined after 1 year on average in a prospective study. The evaluation was made using the Harris Hip Score. The advantages and disadvantages of the Robodoc-assisted surgery are described.

RESULTS

More than 80% of the patients had a good or very good result (> 80 points of Harris Hip Score) 3 month after surgery; after 6 months in 20 of 21 patients a score of more than 85 pts. was calculated. The following complications were noticed: thrombotic embolism (2) with one lethal embolism included, fracture of the greater trochanter using the straight stem (3), aseptic drainage due to hematoma (2). 12 patients noticed a postoperative pain at the distal marking pin location (condylus femoris medialis) for an average of 3 months.

CONCLUSION

Generally, Robodoc-assisted surgery may be performed in all uncemented total hip arthroplasties. The individual indication should be checked because of the increased effort of surgery, the advantages and disadvantages, and the non-proven better long-term results in comparison to the regular technique. It seems that the Robodoc system provides advantages in post-traumatic arthritis and deformities of the proximal femur (varus and valgus neck) on account of the computer-aided preoperative planning and correct operative realization.

Arthroscopy after dysfunctional total knee arthroplasty: two cases with peg fracture of the polyethylene insert

Arthroscopy may be indicated in patients with painful dysfunction of the knee joint following total joint replacement. Arthrofibrosis, impacted soft tissue, patellar malalignment, synovialitis, and intra-articular foreign bodies can be treated with the promise of a good outcome. Two cases of peg fracture of the polyethylene insert of a semiconstrained knee prosthesis are presented. In relation to fracture position, instability and locking-up of the joint were clinically manifest. When arthroscopy is used judiciously, its merits are found in ensuring the proper diagnosis and in the reliable planning of treatment. When the patient reports locking-up of the joint, the rare complication of a polyethylene peg fracture must be considered.

Results of arthroscopic joint debridement in different stages of chondromalacia of the knee joint

A retrospective study was performed of 161 patients who had undergone arthroscopic operation for chondromalacia of the knee joint. After an average follow-up period of 40 (range 10-72) months, patients with severe articular cartilage lesions who had undergone articular lavage alone showed significantly poorer results (P < 0.001). With the same stage of chondromalacia and having undergone the same surgical procedure, younger patients showed better results than older patients. The more effective interruption of the circulus vitiosus during the development of degenerative joint diseases is the primary cause for better results achieved by mechanical debridement of the joint for patients suffering from grade 2 or higher. According to the literature, aggressive subchondral abrasion in severely degenerated knees does not show any benefits. Apparently, the success of the therapy depends to a great extent on the inferiority of the potential degenerative regenerate (lack of capacity of intrinsic regeneration of the hyaline cartilage) as well as on the grade and the progression of chondromalacia. Almost every second patient suffering from grade 4 chondromalacia complained of recurrent pain 1 year postoperatively. One of every 6 patients received a knee joint prosthesis within the 1st year. Therefore, the patients' preoperative expectations have to be clearly objectified. The surgical procedure as an operation with a low complication risk can also be justified as a temporary alternative to total knee arthroplasty in patients suffering from a high-grade degeneration of the joint.

[The effect of arthroscopic joint debridement in advanced arthrosis of the knee joint]

A retrospective study was performed examining 84 patients who had undergone arthroscopic debridement for high-grade osteoarthritis of the knee joint. After an average follow-up period of 52 (35-72) months only 14 (16.7%) patients indicated an improvement of the preoperative situation. 36 (42.8%) patients had severe joint pain after one year postoperatively. 17 (24.3%) patients were evaluated with 85-100 points and 53 (75.7%) patients with less than 85 points in a modified Lysholm-score. There were better results in younger patients (< 50 years). Compared with the literature, aggressive subchondral abrasion does not show any benefits. Patients' preoperative expectations have to be clearly objectified. With this prerequisite the surgical procedure as an operation with low complication risk can also be justified as a temporary alternative to total knee arthroplasty in patients suffering from a high-grade degeneration of the knee joint.

[ROBODOC--a path into the future of hip endoprosthetics or an investment error?]

GOAL

The Orthopaedic Department of Martin-Luther-University has been using computer-guided, robot-assisted surgery in cementless total hip arthroplasty since June 1997. The goal of the present paper is to critically evaluate the advantages and disadvantages of the ROBODOC system when using two different femoral components and the employment of the system in orthopaedics in general.

METHOD

Between June 1997 and August 1999 87 procedures have been performed using the ROBODOC system. 48 ABG stems and 39 OSTEOLOC stems manufactured by HOWMEDICA were used. The results are based on a prospective study.

RESULTS

The main advantage of the system is the excellent three-dimensional preoperative planning and the precise execution of the preoperative plan during surgery. Problematic situations of the proximal femur can be evaluated and the optimal position of the femoral component can be guaranteed. Investigations on cadaver femurs showed significant differences in the bone-implant contact. The first results let us expect some advantage in congenital and acquired femoral deformities.

CONCLUSION

The ROBODOC system has to be critically considered as an alternative to hand implantation. In our opinion, it should be used only under certain circumstances considering the current technical progress. Only in these cases the potential of the system can be used beneficially.

[Etiology of early loosening after aseptic cup replacement using allogenic bone blocks and cement-free press-fit cups]

PURPOSE

There are two problems using structural allografts in revision total hip surgery. The long-term stability of bulk allografts and the intraoperative primary stability of the graft and implant limit the success of this revision philosophy. The purpose of this study was to analyse the reasons of early loosening of cementless cups after reconstruction with bulk allografts.

METHOD

In a retrospective study 78 revisions were analysed radiologically. The preoperative stage of bone destruction, the size of allografts, the implant-allograft coverage, and the position of implants were analysed in X-ray series.

RESULT

There were 12 (15.3%) cases with aseptic and 5 (6%) cases with septic cup loosening, after revision surgery, with an average follow-up of 37 (25-84) months. All of these failures were registered in the first 12 months postoperatively. Large bone defects and an implant-allograft coverage of more than 50% are significant (p < 0.001) risk factors of early aseptic loosening.

CONCLUSIONS

It is important to give careful attentions to primary stability, especially in revision total hip arthroplasty using structural allografts and cementless cups. For primary stability as well as secondary stability a stable fixation with as large as possible areas of contact between implant and living bone is necessary. The limit of the method (allograft and cementless cup) is to be seen in stage 2B according Paprosky (1990). In larger defects alternative reconstruction methods have to be used.

Cloning non-transformed sheep B cells

The capacity to clone B cells and establish permanent B cell lines has greatly facilitated a wide variety of studies characterising the growth, differentiation, and gene expression of murine and human B cells. Similar investigations of B cell biology for other species have been severely restricted by an inability to culture or clone B cells. This is the first report of a method to clone non-transformed sheep B cells using a culture system based on murine CD154 and a combination of human gamma chain-common cytokines. Sheep Peyer's patch B cells were cultured for 120 days and then cloned by limiting dilution culture. The parental B cell culture contained both surface immunoglobulin (sIg)M(+) and sIgG1(+) B cells and both types of B cell were cloned. Clonality was confirmed by PCR analysis of Ig heavy chain (HC) and light chain (LC) expression and DNA sequencing of HC V genes. There was agreement between the PCR and flow cytometric analyses of HC isotype expression on the B cell clones but the available monoclonal antibodies specific for sheep lambda and kappa LC did not react with all clones. Soluble Ig was detected in the culture supernatant of sIgG1(+) clones but not sIgM(+) clones. The B cell clones remained dependent upon CD154 and gamma chain-common cytokine co-stimulation for sustained growth and maintained stable Ig expression. The cloning of non-transformed sheep B cells should provide a valuable tool for studying sheep B cell biology, establishing Ig HC- and LC-specific monoclonal antibodies, analysing the B cell Ig repertoire, and may be used to produce sheep monoclonal antibodies.

[Effect of ion channel modulators on the membrane potential of human chondrocytes]

As all living cell systems, human chondrocytes are provided with a membrane potential. For its origin the existence of ion channels at the cell membrane is an essential prerequisite. In non-human chondrocytes, different ion channels could already be identified. A connection between the potassium channel activity and the proliferation has been detected in different human cell systems. Whereas, the proof of a connection between ion channel activity of human chondrocytes and the proliferation has yet to be established. In this study the concentration-dependent influence of the ion channel modulators tetraethylammonium (TEA), 4-amino-pyridin (4-AP), 4',4'diisothiocyanatostilbene-2,2'disulfonic acid (DIDS), 4-acetamido-4'isothiocyano-2,2'disulfonic acid stilbene (SITS) and verapamil on the membrane potential and the proliferation of human chondrocytes was investigated using flow cytometry. The results show an effect of the used ion channel modulators causing a change of the membrane potential of human chondrocytes. The decrease of the membrane potential by 18% was measured with 0.25 mmol/l verapamil meaning the maximal measurable effect compared with a control group. When measuring DNA distribution, it became apparent that the human chondrocytes are diploid cells with a very low proliferation tendency. These results allow the conclusion of an influence of ion channel modulators on chondrocyte proliferation.

[Results of the Elmslie-Trillat procedure in cases of patella(sub)luxation related to chondral pathology]

Between May 1981 and December 1993, 120 patients (126 knee joints) were operated using the Elsmlie-Trillat procedure because of patella(sub)luxation. 79 patients were reviewed at an average follow up of 4.1 (1-13.6) years. 46 women and 33 men were operated with an average age at operation of 26.9 (14-59) years. The examination included Bentley's Score, radiological parameters (e. g. grading of patella dislocation), grading of chondromalacia and patient characteristics (e. g. age, pre-operative time). 64 knee joints (70. 3 %) were evaluated 'very good' and 'good', using the score of Bentley. There were significantly worse results in cases with higher grading of chondromalacia (p <0.0036), longer pre-operative time (p < 0.012) and older patients (p < 0.0023). The worst and most highly significant results were in these patients with prior knee surgery (p < 0.0001). A good patella relocation correlated with improved results (p < 0.001). There was no difference in cases with patella dislocation and/or patellasubluxation. In conclusion, the Elmslie-Trillat procedure should be carried out 'in the correct manner and at an early stage'. To optimise the therapy in cases of patella dislocation the high number of operation techniques should be analysed and used regarding risk groups.

[Cerebellar hemorrhage as an early complication of spinal operations. 2. Case reports and review of the literature]

GOAL

The present paper investigates the etiology and pathogenesis of cerebellar hemorrhage after spine surgery.

METHOD

This paper reports two patients in those this complication was seen. In respect to the current literature we discuss the etiology and pathogenesis of cerebellar hemorrhage due to spine surgery.

RESULTS

Cerebellar hemorrhages represent a life-threatening situation. There are no reports in the literature about cerebellar hemorrhage as an early complication of intraoperative dura injuries in spine surgery. It seems that a bigger cerebrospinal fluid loss is responsible for the developing of cerebellar hemorrhages. The loss creates a pressure gradient from infratentoriell to site of lesion and also leads to mechanical stress on cerebellar blood vessels such as traction, tearing and kinking.

CONCLUSIONS

Every condition after spine surgery with dura injuries and neurological deficits should be carefully evaluated and intracranial hypotension as well as hemorrhage should be ruled out.

Biomechanical and densitometric bone properties after callus distraction in sheep

Assessment of biomechanical stability of diaphyseal bone lengthened by callus distraction is an unsolved problem. A middiaphyseal corticotomy was performed in the left tibia of 24 sheep. After 7 days, callus distraction was begun at a rate of 0.5 mm every 12 hours for 30 days using a standard unilateral fixator system. Animals were euthanized 4, 8, or 12 weeks after the end of distraction. The lengthened tibia and the contralateral control tibia from each animal were evaluated by radiographic, densitometric (dual energy xray absorptiometry, quantitative computed tomography), and biomechanical (axial compression testing, torsion testing to failure) methods. The bone mineral density and maximum torque for the lengthened tibia were significantly greater in the 8-week group than in the 4-week group. However, the values in the 12-week group were significantly smaller than in the 8-week group. In the lengthened tibias, there was a correlation between the maximum torque and the bone mineral density, and between the maximum torque and the bone density. Bone density measurements are useful prognosticators for the safe removal of external fixators after leg lengthening procedures. By using these methods, clinical fractures after leg lengthening could be avoided in the future.

Caprine T-cell receptor variable beta-chain (TCRV beta) repertoire analysis and potential applications in cowdriosis immune response studies

Anchor polymerase chain reaction has been applied to the study of caprine TCR V beta-chain repertoire at the mRNA level in peripheral blood of a Saanen goat. Single stranded, g-tailed cDNA synthesized from total RNA was PCR-amplified using a sheep V beta constant region primer (3') and a poly(dC) anchor primer (5') at the variable region end of the TCR V beta-chain. The obtained amplicon was subsequently cloned into Bluescript plasmid vector. A total of 72 recombinant clones whereof 61 contained an insert of appropriate size were harvested. Up to now, the full length sequences of a total of 55 clones have been obtained. Nine clones were rearranged but not functional due to stop codons. Forty-five sequences were functionally rearranged and further analyzed. They were classified into 15 different V beta families on the basis of V-region sequence homology with their human counterpart. V beta families corresponding to the 9 published bovine families were represented in our library. This complexity enables us to develop V beta family-specific primers in order to study the TCR V beta repertoire of other goat breeds of interest, i.e., the Creole goat. There the TCR V beta repertoire analysis and kinetic study of the cowdriosis model will provide insight into the type of the immune response and the status of protection during the immunization process and challenge.

[Possibilities of follow-up imaging after implantation of a carbon fiber-reinforced hip prosthesis]

INTRODUCTION

There are many problems in the radiological diagnosis of aseptic loosening in total hip arthroplasty. Computed tomography (CT) and magnetic resonance tomography (MRT) are not usable for metallic implants (stainless steel, cobalt alloy, titanium alloy).

MATERIAL AND METHODS

From April 1993 to December 1993 15 CFRP non-cemented hip prostheses have been implanted. In a prospective clinical study plane radiographs, CT and MRT have been analysed.

RESULTS

Three stems were revised (1 femoral fracture, 1 severe thigh pain, 1 aseptic loosening). CFRP are not visible in plane radiographs. There was a complete (two-third of the cases) or nearly complete (one-third of the cases) small sclerotic interface between the prosthesis and the bone, these were apparent in CT and MRT in stable implant cases and did not have any clinical correlations.

DISCUSSION

The small sclerotic interface is quite different in comparison to so called "Reactive Lines". In one case of aseptic loosening there was an interposition of soft tissue between prosthesis and bone in MRT and CT. CFRP inaugurates new diagnostic possibilities in aseptic loosening of hip prosthesis and in tumour surgery too.