Degeneration alters the biomechanical properties and structural composition of lateral human menisci.

OBJECTIVE: Because the literature relating to the influence of degeneration on the viscoelasticity and tissue composition of human lateral menisci remains contradictory or completely lacking, the aim of this study was to fill these gaps by comprehensively characterising the biomechanical properties of menisci with regard to the degree of degeneration. DESIGN: Meniscal tissue from 24 patients undergoing a total knee replacement was collected and the degeneration of each region classified according to Pauli et al. For biomechanical characterisation, compression and tensile tests were performed. Additionally, the water content was determined and infrared (IR) spectroscopy was applied to detect changes in the structural composition, particularly of the proteoglycan and collagen content. RESULTS: With an increasing degree of degeneration, a significant decrease of the equilibrium modulus was detected, while simultaneously the water content and the hydraulic permeability significantly increased. However, the tensile modulus displayed a tendency to decrease with increasing degeneration, which might be due to the significantly decreasing amount of collagen content identified by the IR measurements. CONCLUSION: The findings of the current study may contribute to the understanding of meniscus degeneration, showing that degenerative processes appear to mainly worsen viscoelastic properties of the inner circumference by disrupting the collagen integrity.

Difficult to treat: are there organism-dependent differences and overall risk factors in success rates for two-stage knee revision?

OBJECTIVES: Failure after two-stage procedure for periprosthetic joint infection (PJI) is a rare, but devastating complication. Some authors assume a correlation of underlying organisms and recurrence rate. Methicillin-resistant Staphylococci (MRS) and other organisms (quinolone-resistant Gram-negative bacteria, rifampicin-resistant Staphylococcus, Enterococcus, and Candida) are meant to be "difficult to treat" (DTT) with an inferior outcome for two-stage revision. In addition to the type of bacteria, some more risk factors seem to be present. The aim of this study was (1) to detect a difference of reinfection rates between reinfection-causing groups of bacteria ["difficult to treat" (DTT), "easy to treat" (ETT) and methicillin-resistant staphylococci (MRS)] after a two-stage procedure, and (2) find overall risk factors for reinfection in a standardized long (spacer insertion for at least 6 weeks) two-stage procedure for periprosthetic knee infection. METHODS: One hundred and thirty-seven two-stage revisions for periprosthetic knee infection were performed at one tertiary referral center. Finally, 96 patients could be included for analyses. Possible risk factors (comorbidities, prior surgery, etc.) and the types of organisms were documented. Quinolone-resistant Gram-negative bacteria, rifampicin-resistant Staphylococcus, Enterococcus, and Candida were classified as "difficult to treat" (DTT). Methicillin-resistant Staphylococci were summarized as "MRS", all other organism are summarized as "easy to treat" (ETT). Statistical analyses included univariate analysis (t test, Fisher's exact test, Chi square test) and logistic regression analysis. RESULTS: There were no statistical significant differences in recurrent infection rates between organism groups (DTT vs. ETT, p = 0.674; DTT vs. MRS, p = 0.705; ETT vs. MRS, p = 0.537). Risk factors seem to be "need of revision after first stage" (p = 0.019, OR 5.62) or completed second stage (p = 0.000, OR 29.07), numbers of surgeries (p = 0.028) and alcohol abuse (p = 0.019, OR 5.62). CONCLUSIONS: Revision needed during or after a two-stage exchange, numbers of surgeries and alcohol abuse are risk factors for recurrence, a different recurrence rates between organism-groups cannot be shown. The absence of significant differences in recurrence rates points to the importance of the individuality of each periprosthetic infection case: a reduction of necessary surgeries (with a thorough debridement, appropriate antibiotic addition to spacers) and the control of comorbidities (alcohol abuse) appear to be essential components of a two-stage exchange.

[Measurement of acetabular cup inclination in anteroposterior pelvic radiogram : An indicator of quality after primary total hip arthroplasty?] / Die Pfanneninklinationsmessung in der Beckenübersichtsaufnahme : Ein Qualitätsindikator nach Hüft-TEP-Primärimplantation?

BACKGROUND AND OBJECTIVE: Acetabular cup orientation, consisting of pelvic positioning, version and inclination, can influence short-term and long-term results after total hip arthroplasty (THA). The radiographic measurement of acetabular cup inclination represents an indicator of quality for the EndoCert certification in Germany. The purpose of this study was to determine the intrarater and interrater reliability of radiographic measurements of acetabular cup inclination after THA. MATERIAL AND METHODS: In this study four independent investigators with different levels of expertise retrospectively performed measurements on radiograms (anteroposterior pelvic radiogram) from 99 patients. The intraclass correlation coefficient (ICC) and Pearson's correlation coefficient were determined and were considered statistically significant with r > 0.8 and p < 0.05. RESULTS AND CONCLUSION: A high correlation was found for both intrarater and interrater reliability based on determination of Pearson's correlation coefficient and the ICC with r > 0.9 and p < 0.001 for all measurements. Based on these results the radiographic measurement of acetabular cup inclination can be considered as a simple measuring tool with high intrarater and interrater reliability. As cup orientation consists of inclination, version and positioning, the exclusive measurement of cup inclination for radiological quality assessment needs to be discussed critically.

Complications associated with 133 static, antibiotic-laden spacers after TKA.

PURPOSE: Periprosthetic infection after total knee arthroplasty (TKA) is a devastating complication, with a two-stage revision currently the 'gold standard' treatment for chronic infections. There is, however, a lack of information about mechanical complications during this treatment. The purpose of this study was to determine: (1) the rate and type of mechanical complications encountered during a two-stage exchange revision for periprosthetic infection of the knee and (2) possible factors of influence. METHODS: Between 2000 and 2011, 133 patients received an antibiotic-laden cement spacer as part of a two-stage protocol. The overall frequency and types of complication were recorded (fissure/fracture of the tibia or femur, spacer fracture, subluxation of the patella, peroneus affection, wound healing disorder and mobilization under anaesthesia based on a constricted ROM). Also analysed were potential influencing factors (BMI, ASA classification, length of the interval with the enclosed spacer, revision needed after explantation, revision needed after reimplantation, complications after primary TKA, service life of the primary prosthesis) in terms of the overall outcome (possibility of reimplantation, complications during the two-stage protocol). RESULTS: The mean age at the time of the first stage operation was 70.1 ± 9.9 years. Overall, 20 of 133 patients suffered one of the complications mentioned above (15 %). Fracture/fissure of the tibia occurred in nine cases (6.8 %) and fracture/fissure of the femur in three (2.3 %). There were also three mobilizations under anaesthesia after TKA reimplantation, two affections of the peroneus nerve, one spacer fracture, one subluxation of the patella and one wound healing disorder. The influencing factors on the overall outcome were revision after reimplantation (reinfection, p = 0.002), revision after explantation (reinfection, p = 0.044), prior aseptic revision after primary TKA (reimplantation, p = 0.019), and prior two-stage revision (reimplantation, p = 0.002). CONCLUSION: A two-stage revision arthroplasty using a static cement spacer is an effective therapy for infected TKAs. The complication rate of 15 % (including restricted ROM after reimplantation) is acceptable. Influencing factors (revision needed after reimplantation, revision needed after explantation) can be demonstrated and should be avoided during the two-stage protocol.

[Accuracy of hip stem migration measurement on plain radiographs: reliability of bony and prosthetic landmarks]. / Erkennung von Hüftschaftsinterungen am Röntgenbild: Reliabilitätsuntersuchung knöcherner und prothetischer Landmarken.

BACKGROUND: In Germany, more than 150,000 total hip arthroplasties (THA) are performed annually. Early implant migration is supposed to be the best indicator for mechanical failure of femoral stems. Therefore, radiological evaluation of hip stems is routinely done by analyzing plain radiographs of THA. OBJECTIVES: The purpose of this study was to evaluate the accuracy of implant migration measurement on plain radiographs. MATERIAL AND METHODS: Two observers analyzed 44 anterior-posterior radiographs of the pelvis in 22 pain-free patients at least 2 years after implantation of an anatomical hip stem. The evaluation was performed on digital as well as conventional plain radiographs. Intraobserver reliability was analyzed by double measurements of each radiograph and the evaluation of the consecutive series of each patient. The anatomical structures of interest were the greater trochanter and the minor trochanter. Furthermore, the tip of the prosthesis, the shoulder of the implant, and the center of rotation were determined. RESULTS: The conventional measurement technique proved higher accuracy compared to the digital measurement technique. The best anatomical structure was the greater trochanter in the conventional technique and the minor trochanter in the digital technique. The best reference structure with regard to the implant was the shoulder of the prosthesis for both techniques. CONCLUSION: The recommended reference structures for the evaluation of implant migration on plain radiographs are the greater trochanter and the shoulder of the implant for the conventional measurement technique and the minor trochanter and the shoulder of the implant for the digital technique. Migration of an implant should not assumed before a determined difference of 2 mm.

[Minimally invasive total hip arthroplasty - trend or state of the art?: A meta-analysis]. / Minimalinvasive Hüftendoprothetik - nur Trend oder schon Standard?: Eine Metaanalyse.

Minimally invasive approaches in total hip arthroplasty are being used worldwide and continue to grow in popularity. Despite early reports of catastrophic failures, both the number of scientific publications as well as the number of orthopaedic surgeons practicing minimally invasive techniques in total hip arthroplasty are steadily increasing. By means of a systematic review of the literature, the current article weighs the potential advantages and disadvantages of minimally invasive techniques. A shorter skin incision, potentially less muscle damage, a faster rehabilitation and a clinically irrelevant lower blood loss may support the use of minimally invasive techniques. However, the potential impairment of wound cosmetics, the increased risk of periprosthetic fractures, implant malpositioning and lack of long-term results contradict the use of minimally invasive total hip arthroplasty as a standard treatment.

[Current role of minimally invasive total knee arthroplasty. A meta-analysis]. / Aktueller Stellenwert der minimalinvasiven Knieendoprothetik : Eine Metaanalyse.

Minimally invasive approaches are increasingly being used in total knee arthroplasty. By means of a review of the literature the pros and cons of minimally invasive approaches for total knee arthroplasty were analyzed. The potential advantages of reduced postoperative pain and improved early range of motion and mobility are opposed by the risks of malpositioning of the prosthetic components and impaired wound healing. Long-term improvement of knee function and quality of life should not be compromised by techniques promising temporary or secondary advantages.

Antigen combining activity associated with immunoglobulin D.

The titers of antibodies to the benzylpenicilloyl antigenic determinant are increased with specific antiserum to immunoglobulin D, as shown by the enhancement method. This increase in titer is blocked by purified immunoglobulins D protein but not by immunoglobulins of the other four classes.

Outcome of Irrigation and Debridement after Failed Two-Stage Reimplantation for Periprosthetic Joint Infection.

INTRODUCTION: Two-stage revision is the gold standard for the treatment of deep implant infection after knee or hip arthroplasty. Irrigation and debridement may be a treatment option for failed 2-stage revisions in cases where a reinfection occurs within 30 days or the symptoms exist not longer than 3 weeks and is appealing because of its low morbidity. We determined the incidence of recurrent infections following irrigation and debridement for failed two-stage revision hip and knee arthroplasty. METHODS: We performed a single center retrospective review of periprosthetic hip and knee infections treated with a two-stage procedure from 2002 to 2010. All patients that subsequently underwent irrigation and debridement for a subsequent infection were selected for the current study. RESULTS: 440 two-stage revisions were performed between 2002 and 2010. Fifty-one two-stage revisions failed (11.6%). Nineteen failed two-stage revisions were treated with irrigation and debridement; 12 (63.2%) patients remained free of infection at follow-up (mean follow-up: 39 months; range, 24-90 months), infection persisted in 6 patients (31.6%), and 1 patient died (5.3%). CONCLUSIONS: Success rates of irrigation and debridement for failed two-stage procedures are similar to the success rates of irrigation and debridement in primary implant infections. According to the current paper, irrigation and debridement are an acceptable treatment for acute reinfections after failed two-stage revision if performed within the first 30 postoperative days after failed two-stage procedure or if symptoms are present for less than 3 weeks in the presence of a susceptible organism.

Analysis of helper activity on pokeweed mitogen- and interleukin 2-driven immunoglobulin synthesis by neoplastic T4+ cells.

The neoplastic T cells of a series of seven patients with chronic T-cell neoplasia were tested for helper activity on pokeweed mitogen (PWM)-induced and interleukin 2 (IL-2)-induced Ig synthesis. The neoplastic T cells of all patients had a T3+4+8-11+I1- phenotype but differed in expression of the 3A1 antigen. The neoplastic T cells of three patients had helper activity on both PWM- and IL-2-driven Ig synthesis, and in addition produced IL-2 in response to PWM stimulation. Two of these patients had hypergammaglobulinemia. In contrast, the neoplastic T cells in the remaining four patients did not produce IL-2 and did not support PWM-driven Ig synthesis. The T4+ cells of these four patients, however, provided excellent helper activity on IL-2-driven Ig synthesis. These findings emphasize the role of IL-2 in T cell-dependent Ig synthesis and clearly show that IL-2 production is required for helper activity in the PWM-driven system. It is concluded that the combined use of PWM- and IL-2-driven Ig synthesis systems allows separate analysis of IL-2 production and T-helper activity in health and disease.

[Acetabular Osteolysis in Total Hip Replacement - When to Retain the Cup?]. / Azetabuläre Osteolysen bei Hüfttotalendoprothese - wann kann die Pfanne belassen werden?

Periacetabular osteolysis is a frequent long-term complication of cementless total hip arthroplasty. The decision whether to retain or to revise a cup in the presence of osteolysis remains a challenge. The options are regular clinical and radiological check-ups, isolated liner exchange with and without bone grafting, and complete cup revision. Thorough preoperative diagnostics, including a medical history, examination and imaging, are mandatory for correct decision making. In most patients, computed tomography is useful to assess periacetabular osteolysis. If the cup is well-fixed and positioned in an asymptomatic patient without progressive osteolysis and no implant defect or higher grade polyethylene wear and no signs of infection, continuous clinical and radiological monitoring is preferred. If imaging reveals cup loosening, malposition, osteolysis localised in a weight-bearing area, imminent or present periprosthetic fractures, rapid progressive osteolysis, implant defects or massive inlay wear, surgical treatment may be preferred. Cup revision is usually performed in such patients. If the cup is well-positioned and well-fixed in the X-ray, the procedure has to be discussed with the patient individually. Apart from patient-specific risk factors, the risk of further progression has to be assessed. Isolated liner exchange can be performed if the patient is asymptomatic and the cup proves to be stable intraoperatively. It is still unclear whether filling osteolyses through screw holes or osseous windows is of long-term benefit.

Clinical characteristics of anaerobic bactibilia.

During a two-year period, 1,892 patients underwent biliary tract surgery at the Mayo Clinic. Both aerobic and anaerobic bile cultures were performed in 371 patients and 253 of these were positive. Anaerobes were isolated from 100 patients, although only twice in pure culture. Only aerobes grew from cultures from 153 patients. One hundred cases of biliary tract infections involving anaerobes and an equal number involving aerobes only were reviewed in order to determine their clinical characteristics. Prominent features of anaerobic bactibilia included (1) a history of complex, multiple, biliary tract surgeries often involving biliary-intestinal anastomoses and common bile duct manipulation, (2) severe symptoms, (3) high incidence of postoperative infectious complications, especially wound infections. Further analysis of anaerobic biliary infections suggested that Bacteroides fragilis was more often associated with serious pathologic conditions of the biliary tract than was Clostridium.

Purpura fulminans in pneumococcal sepsis.

Two cases of pneumococcal sepsis in splenectomized patients were complicated by purpura fulminans. In addition, acute renal failure developed in both patients, and myolysis in one. Immunological findings in the patient with myolysis suggest a possible role of pneumococcal antigen-containing circulating immune complexes in the pathogenesis of these complications.

[Retention of the prosthesis in early periprosthetic infection after total hip arthroplasty]. / Gelenkerhalt bei Frühinfektion nach Hüfttotalendoprothese.

BACKGROUND: The rate of periprosthetic infection after total hip arthroplasty (THA) without patient-specific risk factors is about 1 %. The therapeutic challenges are control of infection, restoration of hip function and prevention of reinfection. In early infection, "irrigation and debridement" (I&D) with exchange of mobile components and retention of the prosthesis remains an attractive alternative to one- or two-stage revision. However, variable results have been reported in the literature. Recent studies have shown new algorithms of treatment for early infection and acute haematogenous infection after THA. PATIENTS AND METHODS: Recent therapeutic algorithms for early infections after THA and an overview of the literature are presented. We conducted a retrospective analysis of 73 patients with early postoperative infection or acute haematogenous infection (symptoms shorter than 4 weeks) after THA who were treated with I&D, exchange of mobile components and retention of the prosthesis at our hospital between 2002 and 2011. RESULTS: RESULTS from the recent literature have shown that the treatment concept of prosthetic retention can only be successful within a maximum time of symptoms of 3 weeks in cases of haematogenous infection and a maximum time span of 4 weeks after index operation in cases of early infection. In our retrospective study with 73 patients, the treatment was successful (free of infection) in 46 patients (63 %). A persistence of infection occurred in 27 patients (37 %). "Difficult to treat" bacteria were present in 28.8 % of the patients. CONCLUSION: The concept of irrigation and debridement with retention of the prosthesis is a valuable alternative to one- or two-stage revision THA, if a maximum time of 4 weeks after index operation in early infections and a maximum time of symptoms of 3 weeks in haematogenous infections are not exceeded. However, reinfection rates after I&D are higher than after two-stage procedures. Prerequisites for success of the I&D algorithm are a stable prosthesis, operable soft tissues, and germs susceptible to antibiotic treatment.

Antibodies to varicella zoster in cerebrospinal fluid.

The neurologic complications of varicella-zoster (VZ) virus infections are manifested as zoster with or without CNS involvement, encephalomyelitis, or ocular involvement. Usually the association of VZ virus in these conditions has been determined by finding VZ antibodies in the serum. In a few instances, VZ antibodies have been detected in the CSF. We report two cases of VZ virus infection followed by neurologic complications involving the CNS in which VZ antibodies were present in the CSF. These two cases underscore the need and value of determining the presence of VZ antibodies in the CSF in certain instances.

Haemolytic anaemia due to cold agglutinins caused by psittacosis.

A 69-yr-old previously healthy woman, presenting with jaundice and the clinical symptoms of an atypical pneumonia, was hospitalized. Haemolytic anaemia due to cold agglutinins was diagnosed, and erythromycin therapy for a suspected Mycoplasma pneumoniae infection was instituted. Serological testing revealed, however, that the infection was attributable to Chlamydia psittaci. The literature on psittacosis and haematological complications is reviewed. Cold agglutinins are sometimes found in association with psittacosis, but a concomitant haemolytic anaemia is rare.

Disappearance of autoantibody-induced haemolysis after excision of a malignant thymoma.

An 82-yr-old woman presenting with autoimmune haemolytic anaemia was found to have a malignant thymoma. A mild, largely compensated, haemolytic anaemia was observed for 5 weeks; steroid therapy was not instituted. Subsequent excision of the thymoma was followed by prompt and permanent (3-yr follow-up) disappearance of the haemolysis. To date, only two such case reports have been published. In both cases, however, the haemolysis did not abate until some months after excision of the thymoma and subsequent administration of corticosteroids. The history presented here serves to illustrate the intimate relationship between thymomas and certain autoimmune diseases.

A rare cause of a hepatic abscess: diverticulitis of the ileum.

A 41-year-old man with a hepatic abscess due to diverticulitis of the ileum is presented. Drainage of the hepatic abscess and antibiotic therapy resulted in complete recovery. The literature on small bowel diverticulitis and its complications is reviewed. Hepatic abscess is a very rare complication. To our knowledge this is the second case to be described in the literature.

Acute hepatic injury after discontinuation of chemotherapy in a patient with non-Hodgkin's lymphoma and chronic hepatitis B virus infection.

We describe a HBsAg-positive patient with non-Hodgkin's lymphoma who underwent aggressive chemotherapy. After discontinuation of chemotherapy, he developed jaundice due to a reactivation of the hepatitis B. Serum HBeAg and HBV DNA turned positive, indicating active virus replication. Abdominal CT-scan showed a large solitary tumour mass in the liver and the serum alpha-fetoprotein level was extremely high, suggesting HBV-related hepatoma. After discontinuation of chemotherapy, the patient died of non-Hodgkin's lymphoma and hepatocellular carcinoma. Throughout treatment of HBsAg-positive patients with cytotoxic or immunosuppressive therapy, careful monitoring of serum aminotransferase levels and HBV DNA is essential. Aggressive chemotherapy may have to be discontinued or changed to a milder regimen if hepatitis occurs.

[Macrocytosis, polyneuropathy and posterior column disorders caused by malabsorption of protein-bound vitamin B12]. / Macrocytose, polyneuropathie en achterstrengstoornissen door malabsorptie van eiwitgebonden vitamine B12.

This case report concerns a patient with a vitamin B12 deficiency and a normal Schilling test, who had macrocytosis of many years' duration and finally polyneuropathy. All known causes of a vitamin B12 deficiency were excluded. When the Schilling test was performed with egg consumption, excretion of vitamin B12 was clearly diminished. It appears highly likely that this vitamin B12 deficiency developed as a result of malabsorption of protein-bound vitamin B12.