Total knee arthroplasty in valgus knee deformity: is it still a challenge in 2021?

Total knee arthroplasty in valgus knee deformities continues to be a challenge for a surgeon. Approximately 10% of patients who undergo total knee arthroplasty have a valgus deformity. While performing total knee arthroplasty in a severe valgus knee, one should aware with the technical aspects of surgical exposure, bone cuts of the distal femur and proximal tibia, medial and lateral ligament balancing, flexion and extension gap balancing, creating an appropriate tibiofemoral joint line, balancing the patellofemoral joint, preserving peroneal nerve function, and selection of the implant regarding constraint. Restoration of neutral mechanical axis and correct ligament balance are important factors for stability and longevity of the prosthesis and for good functional outcome. Thus, our review aims to provide step by step comprehensive knowledge about different surgical techniques for the correction of severe valgus deformity in total knee arthroplasty.

Migration of the femoral component and clinical outcomes after total knee replacement: a narrative review.

Loosening is considered as a main cause of implant failure in total knee replacement (TKR). Among the predictive signs of loosening, migration is the most investigated quantitative parameter. Several studies focused on the migration of the tibial component in TKR, while no reviews have been focused on the migration of the femoral component and its influence on patients' clinical outcomes. The aim of this narrative review was (1) to provide information about of the influence of migration in femoral component of TKR prostheses, (2) to assess how migration may affect patient clinical outcomes and (3) to present alternative solution to the standard cobalt-chrome prostheses. A database search was performed on PubMed Central® according to the PRISMA guidelines for studies about Cobalt-Chrome femoral component migration in people that underwent primary TKR published until May 2020. Overall, 18 articles matched the selection criteria and were included in the study. Few studies investigated the femoral component through the migration, and no clear migration causes emerged. The Roentgen Stereophotogrammetric Analysis has been mostly used to assess the migration for prognostic predictions. An annual migration of 0.10 mm seems compatible with good long-term performance and good clinical and functional outcomes. An alternative solution to cobalt-chrome prostheses is represented by femoral component in PEEK material, although no clinical evaluations have been carried out on humans yet. Further studies are needed to investigate the migration of the femoral component in relation to clinical outcomes and material used.

Energy production in Ureaplasma urealyticum.

Ureaplasma urealyticum lacks the conventional mechanisms for adenosine 5-triphosphate (ATP) generation, such as glycolysis or arginine breakdown, present in other mycoplasmas. The possibility that ATP may be generated in these organisms through the formation of an ion gradient coupled to urea hydrolysis has been suggested by Masover and Hayflick (Ann NY Acad Sci 225:118-130, 1973). Our data have proved that ATP is produced when urea is added to resting ureaplasmal cells and its formation requires the concomitant activity of both cytoplasmic urease and membrane-bound ATPase and is drastically reduced by carbonylcyanide-m-chlorophenylhydrazine. Analysis of the optimal conditions for ATP synthesis in ureaplasmas indicates that this energetic process depends upon phosphate, urea, pH and ammonium ions in the reaction mixture. Particularly ammonium ions can interfere with the production of energy only when the starting pH is kept slightly basic. We have also shown that the changes in fluorescence intensity are directly related to the concentrations of the added urea and are inhibited by the presence of acetohydroxamic acid, carbonycyanide-m-chlorophenylhydrazine, and ammonium ions. It appears that urea hydrolysis can generate an electrical potential through NH4+ diffusion across the Ureaplasma membranes, but this diffusion is also dependent upon the external acidic pH of the reaction mixture.

Effects of urea phosphate, ammonium ions and pH on Ureaplasma ATP synthesis.

The effects of various reaction conditions and the influence of urea and its hydrolysis products on Ureaplasma ATP synthesis were assayed using of a pH stat system which avoids the unfavourable changes of the external pH. The results proved that ATP synthesis required the presence of an optimal phosphate concentration and was dependent on the urea content of the reaction mixture. The data suggest that urea is the energetic source for ureaplasma growth and ammonium ions and pH could interfere in an additive way with the production of energy, only when the starting pH of the medium is kept in a slightly basic range.

No evidence of HIV 2 infection in Sicily.

A seroepidemiological survey was carried out with the aim of establishing whether or not HIV 2 infection could be detected in Western Sicily. Two groups of sera were tested by EIA and WB assay against HIV 1 and HIV 2. 200 sera taken from North African immigrants in the Mazara del Vallo area, and 297 samples taken from AIDS-high risk groups individuals living in Palermo. None of the North African sera was positive to HIV 1 and/or HIV 2 by either techniques. 118 of the 297 sera from Palermo were HIV 1 positive by both techniques; 69 thereof also reacted to HIV 2 by EIA. Only six of these were confirmed by WB assay, showing a clear reactivity against the 140 and 105 HIV 2 glycoproteins. However, all six sera were considered merely cross-reactive to HIV 2, since none of them had neutralizing antibody to HIV 2 and the cross reactivity to glycoproteins of HIV 2 could be removed by absorbing them with HIV 1 infected cells. It seems therefore that HIV 2 has not yet reached our area. Early detection of the possible presence of this virus in our country could be obtained by improving both the surveillance and the effectiveness of laboratory tools for HIV 2 diagnosis.

Isolation of HTLV III/LAV from drug addicts in Palermo.

The new human retroviruses HTLV III/LAV, implicated as the causative agent of AIDS, have been isolated from peripheral blood lymphocytes of 5 of 13 drugs abusers with acquired immunodeficiency syndrome-related complex (ARC). In one patient the virus was also found in cell-free plasma. No HTLV III/LAV was detected in or isolated from 5 clinically healthy drug abusers. The lymphocytes were cultured with interleukin 2 and expressed either a transcriptase reverse activity or HTLV III/LAV antigens within 2-3 weeks of cultivation. The viruses were also transmitted into normal lymphocytes from cord blood of human newborns. At the present state of development, virological investigation, other than seroepidemiological survey, seems a suitable marker for human retroviruses tracing in epidemiological studies.

Change in size of the envelope glycoprotein of a human immunodeficiency virus 1 (HIV 1) strain.

A strain of HIV 1 (PA 40), isolated from a patient with AIDS, showed a size variation of its external glycoprotein. This glycoprotein had an estimated molecular weight of 105 Kd and differed from that of both HIV 1 IIIb and HIV 2 Rod strains. The protein was derived from a bigger (140 Kd) precursor, detectable only in the infected cells and could incorporate labeled glucose in its prosthetic portion. The change in size of the external glycoprotein may be the result of envelope sequence variations since the unglycosylated form of the envelope precursor of PA 40 strain, detected in tunicamycin treated cells, was smaller than that of the HIV 1 IIIb strain. The different size of the external glycoprotein is a further aspect of the variability of the biological characteristic of HIV 1 strains and might be correlated with the emergence of more virulent variants which arose during the progression of the clinical disease.

Main routes of transmission of human immunodeficiency virus (HIV) infection in a family setting in Palermo, Italy.

A cross-sectional seroepidemiologic study was carried out on household contacts and sexual partners of human immunodeficiency virus (HIV) antibody-positive intravenous drug abusers in Palermo, Italy, in 1985 to evaluate factors that influenced HIV transmission. A total of 43 index cases, 36 spouses or heterosexual partners, 28 children, and 55 adult household members were enrolled. None of the household members without sexual contact, who had shared items and facilities and had interacted with the index cases, contracted HIV infection. However, six of 36 sexual partners had antibodies to HIV. It was observed that the risk of HIV infection was significantly associated with the frequency of sexual intercourse with the seropositive partner. Four children were also found to be infected: two had acquired immunodeficiency syndrome-related complex, and the other two were clinically and immunologically normal. Furthermore, one other child had evidence of passive transfer of maternal antibodies. The infection was confined to the younger children (ranging in age from eight months to three years). The data support a high rate of vertical transmission from mother to infant, an intermediate rate of transmission to sexual partners, and no transmission attributable to household contact.

Further isolation of HIV strains in Palermo: some biological properties of the new isolates.

21 HIV strains were isolated from peripheral mononuclear cells of 31 adult and pediatric patients with AIDS or ARC and 10 apparently healthy HIV seropositive individuals. Viral isolation rate was correlated to the clinical status of patients, being very high in patients with AIDS or ARC, and lower in apparently healthy individuals. 4 isolates were propagated in cultures of a T-cell continuous line (Molt 4) and their biological properties were compared. The capacity to establish a chronic infection on Molt 4 cells and the extent of cytopathic effect of the infected cultures varied among the different strains. Moreover, differences in endpoint titrations of the supernatants and variable effects on cell multiplication and viability of Molt 4 cells were also observed. Our results further substantiate the existence of a wide heterogeneity of HIV strains.

Neutralizing antibody and clinical status of human immunodeficiency virus (HIV)-infected individuals.

An assay based on inhibition of cytopathic effect of human immunodeficiency virus (HIV) strains in Molt 4 cells was developed to quantitate neutralizing antibodies (NA) in sera of HIV-infected individuals. The assay was specific and gave results comparable to those obtained by the inhibition of immunofluorescence (IFI) and reverse transcriptase (RT) activity. Attempts were made to correlate the presence and the antibody titres with the clinical status of HIV-infected individuals classified according to Walter Reed staging classification scheme. NA titres correlated inversely with the stage of HIV infection: Compared with acquired immunodeficiency syndrome (AIDS) patients, HIV-infected subjects at stage WR1 had significantly higher NA titres. Moreover, a decrease in NA titre in relation to clinical deterioration was noted in sequential sera of eight of 11 AIDS patients, retrospectively examined, for NA. The symptomless subjects showed either the same level of NA or a trend towards an increasing antibody titre with time. Different isolates of HIV strains showed a variability in the extent of sensitivity to neutralization by sera obtained from different HIV-infected individuals.

The changing pattern of human immunodeficiency virus type 1 infection in intravenous drug users. Results of a six-year seroprevalence study in Palermo, Italy.

A cross-sectional seroepidemiologic study was carried out between 1985 and 1990 in 1,567 heterosexual intravenous drug users who had been seen at the AIDS Regional Reference Center in Palermo, Italy, to evaluate the rate of human immunodeficiency virus type 1 (HIV-1) seroprevalence in this group and its long-term trend. Sixty serum samples collected from drug users in 1980 and 1983, before the founding of the Center (1985), were tested as well. Some demographic and behavioral risk factors were studied in a subgroup of intravenous drug users enrolled in 1985, 1987, and 1990 for their possible association with HIV-1. These factors were also studied in relation to hepatitis B virus infection, since both viruses share the same modes of spread. These drug users had a higher prevalence of markers for hepatitis B virus than of HIV-1 antibodies, and the prevalence rates in sera collected declined over time for both infections. The presence of both antibodies to HIV-1 and markers for hepatitis B virus was independently associated with the age of the drug user, the duration of drug use, and the year of serum collection. Antibodies to HIV-1 were observed more frequently in females than in males. No relation was found between education or employment status and the presence of HIV-1 antibodies or hepatitis B virus markers. Although new HIV-1 infections still occur, the decline in seroprevalence observed at the end of the 1980s might be related to modifications in social behavior among newer drug users, partial exhaustion of the susceptible population, and increasing risk awareness in more experienced users.

AIDS in Sicily: prevalence of antibodies to human immunodeficiency virus (HIV) in low and high risk groups.

A seroepidemiological survey, carried out to evaluate the prevalence of antibodies to HIV in patients with ARC and in healthy individuals at risk for AIDS, showed the infection to be widespread in the groups at risk, namely in drug abusers and hemophiliacs. However, remarkable difference existed between the prevalence of antibodies to HIV in drug abusers of the city of Palermo and those of other Sicilian provinces. Spread of the virus among Sicilian thalassemics, however, was very low and quite similar in all geographic areas. Antibodies were found very rarely (0.06%) in unpaid voluntary blood donors. The spread of the virus is still confined in high risk groups, and the major part of the seropositive blood donors were identified a posteriori as drug abusers.

Free and antibody-complexed antigen and antibody profile in apparently healthy HIV seropositive individuals and in AIDS patients.

The pattern of free and antibody-complexed HIV antigen and the antibody profile were investigated retrospectively in 305 serum samples taken from 22 AIDS patients before and during the development of AIDS and from 40 apparently healthy seropositive individuals. Most AIDS patients were found positive for both free and complexed antigen and had high gp41 antibody titres but low or undetectable p24 antibody. Four different patterns of HIV antigenaemia were observed: 1) positive for both free and complexed antigen; 2) negative for free HIV antigen at first, but always positive for complexed antigen; 3) positive for free antigen without complexed antigen; and 4) negative for both free and complexed antigen. The development of immune complexes preceded the appearance of free antigen and might reflect the ongoing viral replication with antigen excess and binding of anticore antibodies. No correlation was found between the development of AIDS symptoms and either the duration of free antigen positivity or the level of antigenaemia. A different pattern was observed in apparently healthy seropositive individuals: 90% of whom had high antibody titres to p24 and gp41 and were persistently negative for free and complexed HIV antigen. This study demonstrates that testing HIV markers in sequentially collected serum samples from HIV seropositive individuals is a useful and simple tool for early identification of persons at risk of developing AIDS.