A descriptive analysis of human milk dispensed by the Leipzig Donor Human Milk Bank for neonates between 2012 and 2019

Background

Human milk banking has become an important aspect of Nutritional medicine. It is not just about the provision of mother's own milk (MOM) or donor human milk (DHM) in the hospital, but also a strategy to encourage breastfeeding in the clinical setting and beyond.

Objective

To describe the feeding patterns of hospitalised infants including human milk dispensed by the Leipzig Donor Human Milk Bank (LMB).

Design

A descriptive analysis of daily data on milk feeds dispensed by LMB for hospitalised infants distinguishing between MOM or DHM, either fresh or frozen, and raw/pasteurised milk from 2012-2019.

Results

We included 2,562 infants with median hospitalisation of 23 days, for whom human milk was dispensed on median 76% of those days and other nutrition on the remaining days. Raw MOM and raw DHM comprised 52% and 8% of the dispensed milk, respectively. Dispensing exclusive DHM instead of MOM for at least one full day was required for 55% of the infants, mostly at the beginning but also later during hospitalisation. Exclusive raw DHM was dispensed on at least 1 day for 37% of the infants, in different birthweight strata <1,000 g: 10%, 1,000-1500 g: 11%, 1,500-2500 g: 13% and > 2,500 g: 3%. At discharge, MOM was dispensed for more than 60% of the infants.

Conclusion

During an infant's hospital stay, LMB dispenses various human milk feeds with interspersed DHM resulting in complex intra-individual and time-variant feeding patterns. LMB dispenses raw MOM and especially raw DHM with the intention to retain the properties of human milk unlike a diet containing pasteurised DHM and/or formula. Although raw DHM comprises a small percentage of all dispensed milk, raw DHM is dispensed for a substantial portion of infants. Our results document that dispensing raw DHM, is possible in routine settings.

Make Bayley III Scores Comparable between United States and German Norms-Development of Conversion Equations

AIM

 Bayley Scales of Infant and Toddler Development (Bayley-III) determines scaled scores and converts these into composite scores. It was shown that applying the German and the U.S. manual leads to different results. This study aims to systematically analyze the differences between the U.S. and German Bayley-III version and to develop conversion equations.

METHODS

 This simulation study generated a dataset of pairs of U.S. and German Bayley-III composite scores (cognitive: n = 4,416, language: n = 240,000, motor: n = 314,000) by converting the same number of achievable tasks for 48 age groups. Bland-Altman plot and regression analyses were performed to develop conversion equations for all age groups.

RESULTS

 German and US Bayley-III scores demonstrate distinct slope and interception for cognitive, language, and motor composite scores. Lower developmental performance leads to higher composite scores with U.S. norms compared with German norms (up to 15 points). These differences varied between age groups. With newly developed conversion equations, the results can be converted (R ²> 0.98).

INTERPRETATION

 This study confirms systematic differences between U.S. and German Bayley test results due to different reference cohorts. Our data consider the full age range and add conversion equations. These findings need to be acknowledged when comparing Bayley Scores internationally.

Diclofenac for prophylaxis of heterotopic ossification after hip arthroplasty: a systematic review

BACKGROUND

Heterotopic ossification (HO) is defined as the formation of lamellar bone in extraskeletal soft tissues. HO can be a severe complication after hip arthroplasty but can possibly be prevented by postoperative treatment with non-steroidal anti-inflammatory drugs (NSAIDs) or radiotherapy. Diclofenac is 1 of the most used drugs in HO prophylaxis because it is effective and long established. However, there is still no uniform therapy regimen in terms of duration, dose and side effect profile regarding the application of diclofenac in HO prevention. We have, therefore, conducted the first systematic review investigating diclofenac for HO prophylaxis after hip arthroplasty. The aim of this study is to assess the efficacy, dose and duration of diclofenac therapy in preventing HO after total hip arthroplasty (THA).

METHODS

According to the PRISMA Guidelines we performed a systematic literature search in EMBASE via Ovid, in MEDLINE via PubMed and in the Cochrane Library addressing all studies in English and German regarding the prophylaxis of HO with diclofenac after THA. We identified 731 potential studies and included 6 randomised controlled trials with 957 patients.

RESULTS

The studies were heterogeneous with regard to duration of therapy, dose, comparative group and follow-up period. The therapy duration ranged from 9 to 42 days, the applied diclofenac doses ranged from 75 mg to 150 mg daily. Patients treated with diclofenac showed a significant reduction in the total incidence of HO regarding to the Brooker Classification compared to placebo and no clinically relevant ossifications occured (Brooker III and IV).

CONCLUSIONS

Diclofenac is efficacious in the prevention of HO and can be used routinely after THA. The existing data indicates that a minimum dose of 75 mg diclofenac per day started on the first postoperative day for a minimum of 9 days is needed to prevent HO with an acceptable incidence of side effects, such as gastrointestinal symptoms.

Psychological well-being of early and continuously treated phenylketonuria patients

BACKGROUND

Despite enormous advances in therapy, phenylketonuria (PKU) remains an incurable, inherited metabolic disease requiring life-long treatment with potential to negatively impact quality of life and psychological well-being. Therefore, the aim of this study was to screen early diagnosed and continuously treated children with PKU on psychological strengths and behavioral difficulties.

METHODS

Evaluation of psychological strengths and behavioral difficulties in 49 patients with PKU (23f, 2-17 years) by Strengths and Difficulties Questionnaire (SDQ; self-report 11-17 years and parent-report 2-17 years). Comparison to age, sex and BMI-matched healthy controls (n = 98; 46f).

RESULTS

In patients with PKU and healthy controls median SDQ Total Difficulties Score and median scores of subscales were within the normal range in parent- and self-report, irrespective of sex and age group (children 2-10 years, adolescents 11-17 years). No influence of long-term metabolic control in PKU on SDQ could be revealed. The 2- to 10-year-old boys with PKU showed significantly higher scores in Prosocial Behavior compared to their healthy peers (P = .032). Likewise, adolescent boys with PKU showed fewer Conduct Problems (parent-report, P = .006). Adolescent girls with PKU rated themselves more often as abnormal in the subscale Emotional Problems compared to their healthy peers (P = .041). This subscale was also responsible for a significantly different Total SDQ Difficulties Score between patients and their parents' report (P = .008).

DISCUSSION

SDQ represents a suitable instrument within the care for patients with PKU. Specific aspects, however, require separate consideration and evaluation with respect to this chronic disease. Special attention should be paid on adolescent PKU girls who seem to be at risk to develop emotional problem.

Recommendations for return to sports after total hip arthroplasty are becoming less restrictive as implants improve

INTRODUCTION

Total hip arthroplasty (THA) surgeries are expected to exponentially increase in the upcoming years, likely because of the overall broader indication of THAs. With these developments, an increasing number of younger (< 50 years) and active patients will receive surgical interventions, and expectations for an active lifestyle will accordingly increase. In addition, surgeons now have a growing array of techniques and implant materials to choose from. Despite these developments, evidence to provide the best standard-of-care to patients with high expectations for return to sports (RTS) is scarce and urgently needed. What recommendations do arthroplasty surgeons currently make to patients with high return to sports expectations, what factors may influence their recommendations and what surgical techniques and implant specifications are considered favorable in the treatment of patients with a more active lifestyle? This study was conducted to analyze the current recommendations, patient assessment, and patient counseling after THA to identify trends and relevant factors for surgical decision-making in patients with high-RTS expectations.

MATERIAL AND METHODS

We designed a questionnaire comprising five general items and 19 specific items that included 46 sub-items for hip arthroplasty and conducted a survey among 300 German surgeons specialized in arthroplasty at the German Arthroplasty Society (AE) to assess expert opinions, recommendations, surgical decision-making, and patient counseling for patients with high expectations for RTS after THA.

RESULTS

The majority of surgeons (81.9%) were in favor of RTS after THA. Risks associated with sports after THA were considered minimal (1%), with periprosthetic fractures ranking highest, followed by hip dislocation and polyethylene wear. Some surgical decision-making was influenced by high-RTS expectations in regard to implant fixation, stem type, femoral head diameter, and bearing-surface tribology. We observed an increasingly liberal counseling of patients for high-impact sports.

CONCLUSION

With the improvement of implants and surgical techniques, surgeons are more willing to encourage patients to adopt a more active lifestyle. However, the true long-term limitations need further investigation in future studies.

LEVEL OF EVIDENCE

5 Expert opinions.

Implant contamination as a cause of surgical site infection in spinal surgery: are single-use implants a reasonable solution? - a systematic review

Background

In spine surgery, surgical site infection (SSI) is one of the main perioperative complications and is associated with a higher patient morbidity and longer patient hospitalization. Most factors associated with SSI are connected with asepsis during the surgical procedure and thus with contamination of implants and instruments used which can be caused by pre- and intraoperative factors. In this systematic review we evaluate the current literature on these causes and discuss possible solutions to avoid implant and instrument contamination.

Methods

A systematic literature search of PubMed addressing implant, instrument and tray contamination in orthopaedic and spinal surgery from 2001 to 2019 was conducted following the PRISMA guidelines. All studies regarding implant and instrument contamination in orthopaedic surgery published in English language were included.

Results

Thirty-five studies were eligible for inclusion and were divided into pre- and intraoperative causes for implant and instrument contamination. Multiple studies showed that reprocessing of medical devices for surgery may be insufficient and lead to surgical site contamination. Regarding intraoperative causes, contamination of gloves and gowns as well as contamination via air are the most striking factors contributing to microbial contamination.

Conclusions

Our systematic literature review shows that multiple factors can lead to instrument or implant contamination. Intraoperative causes of contamination can be avoided by implementing behavior such as changing gloves right before handling an implant and reducing the instruments’ intraoperative exposure to air. In avoidance of preoperative contamination, there still is a lack of convincing evidence for the use of single-use implants in orthopaedic surgery.

Relocating a pediatric hospital: Does antimicrobial resistance change?

Objective

Analyze the changes in antimicrobial drug resistance patterns due to hospital relocation. To this end, we conducted a retrospective analysis of microbiological results, especially minimum inhibitory concentrations (MIC) of all isolates from blood, urine and bronchial secretions, in our pediatric university hospital before and after moving to a new building.

Results

While the number of tests done did not change, the fraction of those positive increased, more MICs were determined and certain microbes (A. baumannii, E. faecalis, Klebsiella spp. and P. mirabilis) were detected more frequently. Most changes in MICs occurred in E. faecium (increases in 8 antimicrobials, decreases only in linezolid and gentamicin). For imipenem and aminopenicillins the MICs commonly rose after relocation, the opposite is true for gentamicin and trimethoprim/sulfamethoxazole. The other factors that alter by moving a hospital such as changes in medical personnel or case severity cannot be corrected for, but using MICs we are able to provide insights into changes down to the individual antimicrobial drug and even small changes usually undetectable to the common categorical reporting of resistance.

Safety assessment of microsilver-loaded poly(methyl methacrylate) (PMMA) cement spacers in patients with prosthetic hip infections: Results of a prospective cohort study

Objectives

Preclinical data showed poly(methyl methacrylate) (PMMA) loaded with microsilver to be effective against a variety of bacteria. The purpose of this study was to assess patient safety of PMMA spacers with microsilver in prosthetic hip infections in a prospective cohort study.

Methods

A total of 12 patients with prosthetic hip infections were included for a three-stage revision procedure. All patients received either a gentamicin-PMMA spacer (80 g to 160 g PMMA depending on hip joint dimension) with additional loading of 1% (w/w) of microsilver (0.8 g to 1.6 g per spacer) at surgery 1 followed by a gentamicin-PMMA spacer without microsilver at surgery 2 or vice versa. Implantation of the revision prosthesis was carried out at surgery 3.

Results

In total, 11 of the 12 patients completed the study. No argyria or considerable differences in laboratory parameters were detected. Silver blood concentrations were below or around the detection limit of 1 ppb in ten of the 11 patients. A maximum of 5.6 ppb at 48 hours after implantation of the silver spacer, which is below the recommended maximum level of 10 ppb, was found in one patient. No silver was detected in the urine. Drainage fluids showed concentrations between 16.1 ppb and 23.3 ppb at 12 hours after implantation of the silver spacers, and between 16.8 ppb to 25.1 ppb at 48 hours after implantation. Pathohistological assessment of the periprosthetic membrane did not reveal any differences between the two groups.

Conclusion

Microsilver-loaded gentamicin-PMMA spacers showed good biocompatibility and the broad antimicrobial activity warrants further clinical research to assess its effectivity in reducing infection rates in prosthetic joint infection.Cite this article: V. Alt, M. Rupp, K. Lemberger, T. Bechert, T. Konradt, P. Steinrücke, R. Schnettler, S. Söder, R. Ascherl. Safety assessment of microsilver-loaded poly(methyl methacrylate) (PMMA) cement spacers in patients with prosthetic hip infections: Results of a prospective cohort study. Bone Joint Res 2019;8:387-396. DOI: 10.1302/2046-3758.88.BJR-2018-0270.R1.

Severe gyration and migration disorder in fetofetal transfusion syndrome: two case reports and a review of the literature on the neurological outcome of children with lesions on neuroimaging

INTRODUCTION

Fetofetal transfusion syndrome is a dreaded cause of morbidity and mortality in monochorionic pregnancies.

CASE REPORTS

We present two pairs of twins one of which we have followed for more than 6 years. The donors suffer from cerebral palsy, orofacial, and motor problems, and both are significantly smaller than their recipient twins. Interestingly, cranial MRI revealed medial frontal lobe polymicrogyria, ventriculomegaly, and decreased thickness in both parietal lobes in both donors. We suggest this as a possible feature of fetofetal transfusion syndrome.

REVIEW

A minireview of the literature on neuroimaging and neurodevelopmental outcome in fetofetal transfusion syndrome is presented.

CONCLUSION

While the close resemblance of the imaging features of both cases is likely incidental further study of a connection between migration and gyration disorders and fetofetal transfusion syndrome is warranted.

The value of hepatic resection in metastasic renal cancer in the Era of Tyrosinkinase Inhibitor Therapy

BACKGROUND

The value of liver-directed therapy (LDT) in patients with metastasic renal cell carcinoma (MRCC) is still an active field of research, particularly in the era of tyrosinkinase inhibitor (TKI) therapy.

METHODS

The records of 35 patients with MRCC undergoing LDT of metastasic liver lesions between 1992 and 2015 were retrospectively analyzed. Immediate postoperative TKI was given in a subgroup of patients after LDT for metastasic lesions. Uni- and multivariate models were applied to assess overall survival (OS), progression-free survival (PFS) and disease-free survival (DFS).

RESULTS

Following primary tumor (renal cell cancer) resection and LDT, respectively, median OS was better for a total of 16 patients (41 %) receiving immediate postoperative TKI with 151 and 98 months, when compared to patients without TKI therapy with 61 (p = 0.003) and 40 months (p = 0.032). Immediate postoperative TKI was associated with better median PFS (47 months versus 19 months; p = 0.023), whereas in DFS only a trend was observed (51 months versus 19 months; p = 0.110).

CONCLUSIONS

LDT should be considered as a suitable additive tool in the era of TKI therapy of MRCC to the liver. In this context, postoperative TKI therapy seems to be associated with better OS and PFS, but not DFS.

Pulmonary metastasectomy for metastasized hepatocellular carcinoma after liver resection and liver transplantation: a single center experience

BACKGROUND

The role of surgery in the treatment of metastasized hepatocellular carcinoma (HCC) remains uncertain. We here report our single centre experience with pulmonary metastasectomy (PM) for metachronous HCC metastases to the lung following curative liver resection (LR) and liver transplantation (LT), respectively.

METHODS

Of 270 patients with HCC being treated by LR or LT at the University Hospital of Leipzig between January 1996 and July 2014, PM was performed in the follow up of 10 patients because of metachronous pulmonary HCC metastases. We retrospectively analyzed demographic and clinicopathological factors as well as the outcome after primary and secondary tumor treatment in these patients.

RESULTS

Following LR/LT and metastasectomy, respectively, mean overall survival was 4.58 ± 0.84 years and 2.4 ± 0.69 years. Postoperative morbidity after primary and secondary tumor treatment was 30 % and 20 %, respectively. Perioperative 30-day mortality was 0 %. Univariate analysis suggest tumor grading (p < 0.05), and a disease free-intervall > 1 year (p = 0.02) as significant prognostic parameters for survival in our collective.

CONCLUSION

PM can be performed safely with a reasonable morbidity even in immunosuppressed patients after LT. Further studies are needed to evaluate whether PM can increase long-term survival in selected patients with resectable metastases and represents an alternative or additive treatment modality to the protein kinase inhibitor sorafenib.

The value of liver resection for focal nodular hyperplasia: resection yes or no?

Background

Focal nodular hyperplasia (FNH) are benign lesions in the liver. Although liver resection is generally not indicated in these patients, rare indications for surgical approaches indeed exist. We here report on our single-center experience with patients undergoing liver resection for FNH, focussing on preoperative diagnostic algorithms and quality of life (QoL) after surgery.

Methods

Medical records of 100 consecutive patients undergoing liver resection for FNH between 1992 and 2012 were retrospectively analyzed with regard to diagnostic pathways and indications for surgery. Quality of life (QoL) before and after surgery was evaluated using validated assessment tools. Student’s t test, one-way ANOVA, χ², and binary logistic regression analyses such as Wilcoxon–Mann–Whitney test were used, as indicated.

Results

A combination of at least two preoperative diagnostic imaging approaches was applied in 99 cases, of which 70 patients were subjected to further imaging or tumor biopsy. In most patients, there was more than one indication for liver resection, including tumor-associated symptoms with abdominal discomfort (n = 46, 40.7 %), balance of risk for malignancy/history of cancer (n = 54, 47.8 %/n = 18; 33.3 %), tumor enlargement/jaundice of vascular and biliary structures (n = 13, 11.5 %), such as incidental findings during elective operation (n = 1, 0.9 %). Postoperative morbidity was 19 %, with serious complications (>grade 2, Clavien–Dindo classification) being evident in 8 %. Perioperative mortality was 0 %. Liver resection was associated with a significant overall improvement in general health (very good–excellent: preoperatively 47.4 % vs. postoperatively 68.1 %; p = 0.015).

Conclusions

Liver resection remains a valuable therapeutic option in the treatment of either symptomatic FNH or if malignancy cannot finally be ruled out. If clinically indicated, liver resection for FNH represents a safe approach and may lead to significant improvements of QoL especially in symptomatic patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s40001-015-0181-x) contains supplementary material, which is available to authorized users.

Uncemented femoral revision arthroplasty using a modular tapered, fluted titanium stem: 5- to 16-year results of 163 cases

BACKGROUND AND PURPOSE

Due to the relative lack of reports on the medium- to long-term clinical and radiographic results of modular femoral cementless revision, we conducted this study to evaluate the medium- to long-term results of uncemented femoral stem revisions using the modular MRP-TITAN stem with distal diaphyseal fixation in a consecutive patient series.

PATIENTS AND METHODS

We retrospectively analyzed 163 femoral stem revisions performed between 1993 and 2001 with a mean follow-up of 10 (5-16) years. Clinical assessment included the Harris hip score (HHS) with reference to comorbidities and femoral defect sizes classified by Charnley and Paprosky. Intraoperative and postoperative complications were analyzed and the failure rate of the MRP stem for any reason was examined.

RESULTS

Mean HHS improved up to the last follow-up (37 (SD 24) vs. 79 (SD 19); p<0.001). 99 cases (61%) had extensive bone defects (Paprosky IIB-III). Radiographic evaluation showed stable stem anchorage in 151 cases (93%) at the last follow-up. 10 implants (6%) failed for various reasons. Neither a breakage of a stem nor loosening of the morse taper junction was recorded. Kaplan-Meier survival analysis revealed a 10-year survival probability of 97% (95% CI: 95-100).

INTERPRETATION

This is one of the largest medium- to long-term analyses of cementless modular revision stems with distal diaphyseal anchorage. The modular MRP-TITAN was reliable, with a Kaplan-Meier survival probability of 97% at 10 years.

[Revised consensus classification. Histopathological classification of diseases associated with joint endoprostheses]

The revised classification of the periprosthetic membrane (synovial-like interface membrane SLIM) encompasses all pathological alterations which can occur as a result of endoprosthetic replacement of major joints and lead to a reduction in durability of prostheses. This also includes the established consensus classification of SLIM by which aseptic and septic prosthetic loosening can be subdivided into four histological types and histopathological criteria for additional pathologies: endoprosthesis-associated arthrofibrosis, immunological/allergic alterations and osseous pathologies. This revision represents the foundation for the histopathological diagnostics of the total spectrum of diseases associated with joint prostheses, is a suitable basis for a standardized diagnostic procedure and etiological clarification of endoprosthesis failure and also as a data standard for endprosthesis registers, in particular for registers based on routine data (e.g. German endoprosthesis register).

Impaction grafting in the femur in cementless modular revision total hip arthroplasty: a descriptive outcome analysis of 243 cases with the MRP-TITAN revision implant

Background

We present a descriptive and retrospective analysis of revision total hip arthroplasties (THA) using the MRP-TITAN stem (Peter Brehm, Weisendorf, GER) with distal diaphyseal fixation and metaphyseal defect augmentation. Our hypothesis was that the metaphyseal defect augmentation (Impaction Bone Grafting) improves the stem survival.

Methods

We retrospectively analyzed the aggregated and anonymized data of 243 femoral stem revisions. 68 patients with 70 implants (28.8%) received an allograft augmentation for metaphyseal defects; 165 patients with 173 implants (71.2%) did not, and served as controls. The mean follow-up was 4.4 ± 1.8 years (range, 2.1–9.6 years). There were no significant differences (p > 0.05) between the study and control group regarding age, body mass index (BMI), femoral defects (types I-III as described by Paprosky), and preoperative Harris Hip Score (HHS). Postoperative clinical function was evaluated using the HHS. Postoperative radiologic examination evaluated implant stability, axial implant migration, signs of implant loosening, periprosthetic radiolucencies, as well as bone regeneration and resorption.

Results

There were comparable rates of intraoperative and postoperative complications in the study and control groups (p > 0.05). Clinical function, expressed as the increase in the postoperative HHS over the preoperative score, showed significantly greater improvement in the group with Impaction Bone Grafting (35.6 ± 14.3 vs. 30.8 ± 15.8; p ≤ 0.05). The study group showed better outcome especially for larger defects (types II C and III as described by Paprosky) and stem diameters ≥ 17 mm. The two groups did not show significant differences in the rate of aseptic loosening (1.4% vs. 2.9%) and the rate of revisions (8.6% vs. 11%). The Kaplan-Meier survival for the MRP-TITAN stem in both groups together was 93.8% after 8.8 years. [Study group 95.7% after 8.54 years ; control group 93.1% after 8.7 years]. Radiologic evaluation showed no significant change in axial implant migration (4.3% vs. 9.3%; p = 0.19) but a significant reduction in proximal stress shielding (5.7% vs. 17.9%; p < 0.05) in the study group. Periprosthetic radiolucencies were detected in 5.7% of the study group and in 9.8% of the control group (p = 0.30). Radiolucencies in the proximal zones 1 and 7 according to Gruen occurred significantly more often in the control group without allograft augmentation (p ≤ 0.05).

Conclusion

We present the largest analysis of the impaction grafting technique in combination with cementless distal diaphyseal stem fixation published so far. Our data provides initial evidence of improved bone regeneration after graft augmentation of metaphyseal bone defects. The data suggests that proximal metaphyseal graft augmentation is beneficial for large metaphyseal bone defects (Paprosky types IIC and III) and stem diameters of 17 mm and above. Due to the limitations of a retrospective and descriptive study the level of evidence remains low and prospective trials should be conducted.

[Designing a surgical device for harvesting autologous fascia lata grafts as a minimal invasive procedure]

AIMS

Fascia lata is used in different shapes and sizes as a graft material in surgical procedures. The conventional method of harvesting a fascia lata graft is through a long skin incision on the lateral aspect of the thigh. Minimal invasive procedures have been established to reduce the disadvantages of an extensive surgical approach for obtaining the autotransplant. However, they do not facilitate to suture the remaining fascia after harvesting the transplant and therefore bear the risk of a symptomatic herniation of the muscle belly. The aim of this study was to design a surgical device to harvest a fascia lata graft and close the resulting fascia defect as a minimal invasive procedure.

MATERIALS AND METHODS

The prototype was tested in 11 human cadaver specimens. It was introduced subcutanously via two small skin incisions. The device contained a special fixation- and working mechanism which enabled the fascial closure using a continuous suture. After the harvest procedure, both the transplant and the sutured fascia lata were examined.

RESULTS

The experiments demonstrated the suitability of this method for minimal invasive harvesting of fascia lata. The removed transplants complied in all experiments with the expected dimensions. The continuous suture of the femoral fascia ran with accurate gaps between the sutures and constant tension without dehiscence. Neither the transplant nor the tissue in the region of harvest have shown unduly macroscopic damage due to the use of the device.

CONCLUSION

The designed prototype can be used for harvesting a fascia lata graft and repairing the resulting defect minimal invasively. Clinical implementation seems possible. However, improvements could be made mainly concerning the handling of the device.

Erythrocytes and proinflammatory mediators in wound drainage

BACKGROUND AND OBJECTIVES

Retransfusion of shed blood collected after operation has become popular, but recent reports of side effects led to a search for possible causes.

MATERIALS AND METHODS

In a randomized study of 28 patients undergoing total hip arthroplasty, shed blood was collected in Solcotrans, Orth-Evac, and ordinary Redon drainage. Osmotic fragility was measured and electron-microscopic pictures of erythrocytes from selective samples were taken. Serotonin, prostaglandin E2 (PGE2), and histamine were measured with enzyme-linked immunosorbent assays.

RESULTS

Higher osmotic fragility of erythrocytes collected with Solcotrans appeared to be due to ACD which was used only with that system. Serotonin concentrations did not differ significantly. However, there was a great increase in histamine (Solcotrans 477.7, Orth-Evac 344.0, Redon drainage 453.1 nmol/ml) and PGE2 (Solcotrans 1,908.3, Orth-Evac 1,225.0, Redon drainage 2,666.7 microgram/ml) in shed blood compared with venous blood (histamine 9.5 nmol/l, PGE2 4.2 microgram/ml).

CONCLUSION

Unwashed wound drainage blood collected after operation contains levels of proinflammatory mediators that can account for the reported side effects.

[Interspecies comparison of healing standardazed bone defects with and without autogenous bone transplantation]

This study tries to establish a basis for comparison of animal studies regarding bone defect healing. Pigs, sheep and rabbits were operated on according to a standardized scheme where each received bilateral defects of the femoral condylus. One of the defects was filled with cancellous autograft, the other remained empty. Bone defect healing was followed with several different methods of investigation, the results were put into perspective with the help of a standardized score-scheme.

[Rapid prototyping. Construction of a model in the preoperative planning of reconstructive pelvic interventions]

X-ray or CT images allows only a limited three-dimensional orientation in presurgical planning. Especially for the planning of internal hemipelvectomies with custom-made endoprosthesis and for peri-acetabular osteotomies a high-grade orientation is necessary. This orientation is improved by a 3D CT-controlled manufactured 1:1 model of the pelvis. This enables and exact classification of defect and deformity, planning of resection planes, design of the suitable custom-made implant and simulation of the operation technique as preoperative quality control.

[Tribological properties of carbon fiber-reinforced plastic. Experimental and clinical results]

Wear of the articulating components (especially PE-UHMW) of total hip endoprostheses is the most important technical factor limiting the functional lifetime. To minimize wear debris, ceramic heads, according to ISO 6474 (Al2O3), have been used, from 1969 paired with Al2O3 and since 1975 paired with PE-UHMW. Al2O3 balls articulating with cups made from CFRP have been in clinical use since 1988. Laboratory experiments and in-vivo testing showed minimized wear debris and mild biological response to wear products using CFRP (carbon fiber reinforced plastic) instead of PE-UHMW as the cup material. The articulating surfaces of retrieved ceramic heads (Al2O3-Biolox) and cementless CFRP cups (carbon fiber reinforced plastic, Caproman) were compared using sphericity measurement techniques, scanning electron microscopy (SEM) and roughness measurements (including advanced roughness parameters Rvk or Rpk according to ISO 4287). Altogether, the first results of the clinical study showed that the combination Al2O3-ball/CFRP-cup came up to the expected lower wear rates compared with the conventional combinations. The wear rates are comparable with the combination Al2O3/Al2O3 without the material-related problems of ceramic components in all ceramic combinations.

Extracorporeal irradiation and incorporation of bone grafts. Autogeneic cortical grafts studied in rats

The incorporation of resected, extracorporeally irradiated (1, 5, 25 and 50 kGy) and orthotopically reimplanted autogeneic cortical bone was investigated in 116 adult Wistar rats. 7 mm-long diaphyseal segments of the tibia were resected, irradiated and reimplanted using K-wire osteosynthesis. Autogeneic fresh grafts served as controls. Graft healing was evaluated by radiography and histomorphometric study at 3, 6, 9, and 12 weeks. At 3 weeks, two thirds of the 50 kGy irradiated grafts were fractured and therefore the series with this dose was interrupted because of mechanical graft insufficiency. After 3 and 6 weeks there were no statistically significant differences among the control group and 1 or 5 kGy irradiated grafts. The healing of 25 kGy irradiated grafts was delayed from the sixth week onwards and continued until the end of the experiment at 12 weeks (50% reduction of incorporation). The incorporation of 1 and 5 kGy irradiated grafts showed a 16% (1 kGy) to 24% (5 kGy) delay at 12 weeks, compared to autogeneic fresh grafts. 1 and 5 kGy irradiated autogeneic bone grafts retain most of their biological potential. Resection, extracorporeal irradiation and reimplantation of bone tumors may therefore be a possible alternative to allografting.

[A method for determining the biomechanical properties of trabecular and spongiosa bone tissue]

With the aim of determining the biomechanical properties of cancellous bone, a method was developed that permits the investigation of the effects of tensile and compressive forces on cancellous bone trabeculae while eliminating the problem of porosity. Individual, rod-like trabeculae were removed from cancellous bone with the aid of special instruments. Each end of a trabeculae was embedded in a cylinder of polymethylmethacrylate. To keep bending moments to a minimum while testing, the trabeculae was aligned along the longitudinal axis of the cylinders with the aid of positioning instruments. With a test apparatus, the deformation behaviour and maximum strength of the trabeculae under tension and compression can be determined under both dry and moist conditions. With account being taken of shape and dimensions of the trabeculae, the material properties of the cancellous bone tissue can be computed. In comparison with the small number of methods so far used for investigating trabeculae, a number of advantages were found: 1. Tensile and compression testing in a single specimen, 2. testing under reliably moist conditions, 3. non-destructive testing enabling further investigations on the specimen.

[Mechanical stability of hip joint endoprosthesis shafts of carbon fiber composite materials]

The use of composite materials in orthopaedic surgery permits the design of implants with varying degrees of stiffness. A system of carbon fibre reinforced epoxy hip stems was investigated and compared to the mechanical safety of metal ones. Special attention has been paid to the fact that torsional moments are the common failure mechanism of composite materials. In total 74 hip stems (three different sizes) have been tested under static and dynamic loading conditions according to ISO 7206. A group of 27 implants was pre-conditioned for 75 days in 80 degrees C Ringer's solution to discover potential degradation effects of absorbed fluids. The carbon fibre hip stems proved to reach run-out loads higher than conventional metal ones. Moisture absorption didn't influence the mechanical properties within the range of the experimental accuracy. The calculated fatigue stress of 750 MPa permits further optimization of stiffness parameters without the risk of implant fracture.

[Biomechanics of healing of cortical autotransplants after intramedullary nailing and device removal]

The aim of the study was to investigate the biomechanical properties of segmental cortical autografts subjected to extracorporeal treatment. For this purpose, 12 beagle dogs were submitted to tibial osteotomy, when 25 mm-long diaphyseal segments of bone were removed and treated outside the body by autoclaving or gamma radiation (Co, 5 kGy). Subsequently, osteosynthesis involving the use of medullary nailing was performed. After 36 weeks, the dogs were killed painlessly and, after removing the nails, the tibias were tested for the biomechanical properties. In comparison with the contralateral tibia, a mean stiffness of 47% and 32% was measured for tibia treated by irradiation and autoclaving, respectively, while bending showed an increase of up to 590%. These results show the need to allow plenty of time for healing in the case of weightbearing transplants. When bealing is undisturbed, no biomechanical differences are found between proximal and distal osteotomies, although in the X-ray image the osteotomy gap (fracture line) remains visible, and scintigraphic activity persists for a longer period. This means that the radiological aspect of the former does not necessarily reflect actual biomechanical strength.

[Preservation and sterilization of cortical bone--biomechanical studies of the rat]

The biomechanical properties of cryopreserved, autoclaved, irradiated and chemically treated cortical bone harvested from rat tibiae were evaluated in three-point bending. Biomechanical parameters (maximum bending load, deflection, failure energy and stiffness) are not altered by cryopreservation (-70 degrees C, 28 days) or irradiation with doses of 1 kGy or 5 kGy. The maximum bending load of autoclaved (134 degrees C, 3 min) or irradiated (25 kGy) cortical bone is reduced to 82% and 74% compared that of controls tested immediately after death (100% = 74.4 +/- 6.6 N). Extension of the autoclaving time from 3 to 5 min or irradiation with 50 kGy diminishes the bending load (28% after autoclaving, 48% after irradiation), deflection and failure energy. Stiffness is altered by autoclaving only. If a sterilization process is combined with deep freezing, better biomechanical values are obtained by sterilizing the bone before deep freezing than vice versa. The bending loads for autoclaving and irradiation before deep freezing are 68.8 +/- 9.4 N and 50.8 +/- 7.9 N, as against 51.7 +/- 2.7 N and 43.1 +/- 3.9 N for autoclaving and irradiation of previously cryopreserved bone. Whereas treating bone with tetrahydrofurane does not alter its biomechanical behavior, 80% ethanol leads to a reduction of structural properties.

[Experimental studies of the biomechanical properties of hollow nails and solid nails for interlocking intramedullary nailing in the dog]

Since locked intramedullary nailing of the tibia in dogs was followed by material failure of the conventional slotted hollow nails within days, special solid nails were developed and tested with respect to their mechanical properties. There was a clear advantage of the solid nails over the hollow nails in terms of bending resistance and yield force. In animal experiments--even in long-term experiments over nine months--no case of material failure occurred with the solid nails. The high torsional and bending resistance of the solid nails suggests the use of a mechanical device which, as our experience shows, permits reliable interlocking without the need for an image intensifier, that is to say, without radiation exposure.

Effects of preservation and sterilization on cortical bone grafts. A scanning electron microscopic study

The effects of preservation and sterilization on the structural properties of cortical bone were investigated. Specimens of cortical bone from rat tibiae were frozen (-70 degrees C for 28 days), freeze-dried, irradiated (1, 5, 25 and 50 kGy) or autoclaved (at 134 degrees C for 3 or 5 min), and examined by scanning electron microscopy. Cryopreservation and irradiation had no deleterious effects on the surface structure of the cortical bone. Freeze-drying caused microcracks running parallel to the mineralized fiber bundles. After autoclaving, a time-dependent distension, swelling and amalgamation of the fibrillary matrix was observed. This denaturation of the organic matrix was more pronounced after 5 min than 3 min autoclaving. The alterations of the fibrillary structure described above might be due to a preservation- and sterilization-induced decrease of the biological and biomechanical potential of bone grafts.

[Partial endoprosthetic reconstruction of the pelvis in malignant tumors]

Twenty-five patients underwent an internal hemipelvectomy with endoprosthetic reconstruction of the pelvis for primary bone tumor (n = 17) or bone metastasis in the pelvis (n = 8). According to the Enneking tumor classification system, there were 9 stage II B tumors and 16 stage III. Conventional metal or polyacetal prostheses were used in 5 cases, and in 20 anatomically adaptable modular prostheses with intramedullary anchorage were implanted. In the last 11 cases a 3D CT-controlled manufactured model of the pelvis was used. The functional results according to Enneking were good in 5 cases, fair in 11, and poor in 7. The last endoprosthetic system showed better results, because it is easier to implant and the possibility failure is reduced. The learning curve of the surgeon is important, too.

[Biomechanical studies of change in the patellar tendon after transplant removal]

The reconstruction of the anterior cruciate ligament deficient knee with the patellar tendon is the "gold standard". Dislocation of the patella, rupture of the patellar tendon and fracture of the patella were reported to occur. In this biomechanical investigation on the changes of the patellar tendon following harvesting of a graft, 51 sheep knee underwent destructive testing at t0 (n = 11), 4 weeks p.op. (n = 5), 3 months p.op. (n = 14), 6 months p.op. (n = 15), and 12 months p.op. (n = 6). Harvesting of a graft produces a stiffness and strength of the patellar tendon of 50-70% of normal. There was no significant change of free patellar tendon length up to 12 months p.op. The cross-sectional area is definitely increased (p < 0.05). The tensile stress is always above normal, nevertheless the strength shows a massive decline until 6 months p.op. and does not regain normal strength by one year p.op. Stiffness shows comparable biomechanical pattern like tensile stress. There are time-dependent changes, the structural weakness is compensated by an increase of cross-sectional area. There is no restitution of the patellar tendon ad integrum, the remainder is a defect with scar tissue and alterated biomechanical properties. Revision surgery using the same host patellar tendon cannot be recommended.

[Radioactivity of bone cement]

A total of 14 samples of different types of bone cement from five different manufacturers were examined for their radioactivity. Each of the investigated bone cements showed a low radioactivity level, i.e. between < 1 and 100 Bq/kg. The content of U-238 and K-40 always was below the limit of detection (< 1-< 10 Bq/kg). Significant differences were detected in the amount of Ra-226, Pb-210, and Ra-228 detected between different samples of the same product from the same manufacturer, as well as between various types of cements. The highest radioactivity level was measured for Ra-226. Although stochastic radiation effects can not totally be excluded, it is extremely unlikely that the small amount of radioactive substances additionally transferred into the body by the bone cement has negative effects on the recipient's organism or on the fate of the alloplastic implant: "The risk factor and extrapolation in a low dosage range ... do not lead to an underestimation but more likely to an overestimation of the radiation hazard" [18].

[The value of epidemiologic studies of ski injuries]

The Garmisch-Partenkirchen experience--15,513 skiing injuries between 1972 and 1990--was compared to the results of an inquiry into the skiing injuries among 565 persons of the medical profession, that were active skiers over an average of 18 years. The parameter injuries per 1000 skiing days was calculated from the outpatient clinic data as well as from all skiing injuries that had happened in the interview group and those that required surgical treatment. The mean value of 2.7 injuries/1000 skiing days--corrected for the number of patients--from the literature and the clinical data with 2.1 is comparable to the 1.8 injuries/1000 skiing days (injuries that required surgical treatment) but stands sharply against the 4.2 arising from the total number of injuries in the inquiry group.--Thus, every epidemiological study clearly underestimates the actual rate of skiing injuries. This fact may be defined as the "bypass-effect". The comparison between clinical setting and inquiry allowed for a quantification: Depending on the type of injury and the study design, a true prevalence of skiing injuries that is between 10% and 200% higher than the published data has to be expected.--Descriptive, not controlled epidemiologic studies on skiing injuries are justified and give valid trends on which therapeutic and prophylactic measures can be based--but exclusively under the following prerequisite conditions: 1. a standardized study protocol; 2. an observation.

[Experimental studies of thermal disinfection and sterilization of allogeneic bone transplants and their effects on biological viability]

Thermal energy (80 degrees) for the disinfection of cancellous allogenic bone grafts was employed, and it proved to be an advantageous, safe and easily accessible method. The effects of this treatment on biological values were examined in terms of biomechanical and biodynamic (graft incorporation) loss of the treated grafts versus the autoclaved and untreated samples. Given the thermolability of the pathogens in question, the thermal approach presented here has the advantage of being readily controllable. The lack of toxic or mutagenic risks through this method and its accessibility represent further advantages. In thermal treatment of bone allografts, it is essential that one knows the thermoconductivity of the bone sample and that one can demonstrate pathogen inactivation through the entire graft volume. All of the parameters in the 80 degrees C group that were measured in this study indicate clear biological superiority over the autoclaved group. A newly developed thermoincubator is introduced for gentler disinfection of allogenic bone grafts and it inactivates common vegetative pathogens as well as HIV. It is still necessary to conduct serological screening for hepatitis antigens in the donor pool, however. Based on these results, we conclude that the clinical use of autoclaved allogenic bone grafts needs to be reviewed and possibly limited.

Cementless prosthesis of the hip joint with "spongy metal" surface. A prospective study

Our investigations in human specimens and animal experiments show that prostheses with a spongy metal surface can become fixed by bony ingrowth to varying degrees. After consistent clinical and radiological follow-up over 12-65 months (mean 34 months) in a prospective study of 100 consecutive patients in whom 106 cementless total hip replacements had been carried out, we were able to show that after 1 year 82% of patients were pain-free with the prosthesis fixed by bony ingrowth, 8% were pain-free with the prosthesis fixed by dense fibrous tissue and 10% were not pain-free, but did not want revision surgery. Thigh pain decreased steadily from 53% 3 months postoperatively to 6.6% 15 months after operation. We believe that, when the implantation technique is exact, a high percentage of cementless spongy metal prostheses are fixed by bony ingrowth, and that a cementless prosthesis should be implanted only in patients under 60 years of age without osteoporosis.

Quantitative effects of allogeneic small-bowel transplantation on nutrient digestion and on body protein balance as determined in vivo in rats

Heterotopic and orthotopic small-bowel allotransplantation was carried out in Wistar rats using grafts reduced to one-half of the original length. Portocaval venous anastomoses and intestinal end-to-end anastomoses were performed. Animals either with complete or with partially reduced native small-bowel served as control. In a total of 51 rats, 88 quantitative in vivo measurements of apparent digestion and absorption of dietary dry matter, organic matter, energy, protein, fat, total ash, and glucose were carried out. Body protein retention was calculated from intake and losses with feces and urine. The digestion trials comprised 8 days of adaptation and 10 days of continual recording of nutrient balance data. In experiments 1 and 2, digestibility coefficients were obtained before and after transplantation within the same animals, untreated or initially treated with cyclosporine A after surgery. Similar groups of rats untreated, with partial resection and with transplantation of the small-bowel, followed by temporary cyclosporine treatment, were used in experiment 3. In experiment 4, rats with transplanted intestines from experiments 1 and 2 were subjected to a further digestion trial 4 to 6 months after the respective first trial. With transplantation of the small intestine, apparent digestion and absorption of nutrients, as well as protein retention, tended to be lower. Significant depression occurred in the digestion of fat and ash. In long-term survivors all parameters decreased further. The adverse effects on fat and ash digestion seemed to be pronounced when rejection occurred. Fecal fat excretion might therefore be an indication of dysfunction of small-bowel grafts. Digestion was less imparied if cyclosporine was applied, and part of the effects on digestion and protein balance could be attributed to the shortened bowel.