553 Does Patella Implant Design Affect Outcomes? Patella Resurfacing in Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

Aim

To investigate whether implant design affect (1)incidence of anterior knee pain, (2)patient reported outcomes and (3)reintervention rates in a resurfaced vs non-resurfaced Total Knee Arthroplasty (TKA).

Method

MEDline, pubmed and google scholar studies were evaluated using SIGN assessment tool and data analysis was conducted using Review Manager 5.2 on only randomised controlled trials. Search terms: arthroplasty, replacement, knee (Mesh), TKA, prosthesis, patella, patellar resurfacing, patellar retaining.

Results

33 randomised controlled studies were identified. A total of 11 used the modern “patella-friendly” implants and 22 used the older “patella non-friendly” implants.

There was no significant difference in anterior knee pain rates for either surgical option. When using patella-friendly implant, patella resurfacing results in a statistically higher clinical (P 0.007, MD -0.77) and functional (P < 0.0001, MD -1.87) KSS than the non-resurfaced counterparts, but scores were not clinically significant. When the patella was not resurfaced, there was a significant increased risk of reoperation with “non-patella friendly” implant (p=0.04, OR 1.42, CI 1.01, 2.00), whilst there was no significant difference between reoperation rates for the “patella friendly” implants (OR 1.17, CI 0.59,2.30).

Conclusions

Patella implant design has been shown to significantly improve KSS scores but with no clinical significance. Risk of further procedures was significantly higher in non-resurfaced patella TKAs with “non-friendly” implants, likely due to increased rates of anterior knee pain in these older generation implants leading to secondary resurfacing. However, when utilising “patella-friendly” implants, resurfacing does not lower reintervention rates. This meta-analysis finds no clinical indication to resurface the patellar whilst performing a TKA.

Genetic diversity of Merozoite Surface Protein-1 gene block 2 allelic types in Plasmodium falciparum isolates from Malaysia and Thailand

Malaria is the most common vector-borne parasitic disease in Malaysia and Thailand, especially in Malayan Borneo and along the Thailand border areas, but little is known about the genetic diversity of the parasite. Present study aims to investigate the genetic diversity of Plasmodium falciparum isolates in these two countries and eventually contributes to more effective malaria control strategies, particularly in vaccine and antimalarial treatment. One hundred and seventy three P. falciparum isolates were collected from Malaysia (n = 67) and Thailand (n = 106) and genotyped using nested PCR targeting the polymorphic region of MSP-1, block 2. Sequence analysis was conducted to investigate the allele diversity of the isolates. Three allelic families were identified in Malaysian and Thailand P. falciparum isolates, MAD20, K1 and RO33. Sequence analysis revealed that there were 5 different MAD20, 1 K1 and 2 different RO33 for Malaysian isolates. Thailand isolates exhibited greater polymorphism because there were 13 different MAD20, 6 different K1 and 2 different RO33 identified in this study. Multiclonal infections were observed for the isolates in both countries, however, low multiplicity of infection (MOI) was observed for Malaysian (1.1) and Thailand (1.2) isolates. Phylogenetic analysis showed that P. falciparum isolates of Malaysia and Thailand were clustered in the same group for all the allelic families. Population structure of P. falciparum isolates in Malaysia and Thailand exhibit extensive genetic polymorphism but showed high similarities as well as comparable MOI.

Toxoplasmosis in HIV and non HIV prisoners in Malaysia

This is the first Malaysian study to determine the trend and risk factors of Toxoplasma gondii infection in HIV and non-HIV among prisoners in terms of socio-demographic and behavioural characteristics, clinical presentations and haematological distributions. Blood samples from 303 participants, comprising 133 HIV positive and 170 HIV negative inmates were collected in EDTA and plain tubes. Two mls of each blood sample in plain tubes were centrifuged at 1500 rpm for 10 minutes and the sera obtained were subjected to ELISA for detection of Toxoplasma IgM and IgG antibody towards Toxoplasma antigen. Seropositive samples for Toxoplasma IgM or both Toxoplasma IgM and IgG were further tested with Novalisa Toxoplasma gondii IgG avidity test to rule out acute from latent infections. Blood in EDTA tubes were sent to Clinical Diagnostic Lab (CDL), University Malaya Medical Centre (UMMC), Kuala Lumpur for complete blood count and differential count analysis. Overall seroprevalence of anti-T. gondii antibodies was detected in 41.9% (127 out of 303) of the participants. Anti-T. gondii antibodies was detected in 63.2% (84 out of 133) of HIV positive subjects and in 25.3% (43 out of 170) of HIV negative subjects. Seroprevalence of anti-T. gondii antibodies was significantly higher in HIV positive than in HIV negative subjects (OR = 5.06; 95% CI = 3.09-8.30; p < 0.001). The rate of T. gondii seropositivity increased significantly in those aged 40 years and above, HIV positive individuals and those with history of drug abuse. White blood cells (WBCs), neutrophils and basophils counts decreased significantly in those infected with Toxoplasma. Creating awareness about T. gondii infection and follow-up of their status is recommended. Moreover, screening of T. gondii infection in HIV-infected individuals should be considered for better treatment and management, including control and prevention.

A preliminary screening of potentially antimalarial plants against Plasmodium falciparum in vitro

Plasmodium is a blood protozoan parasite that is responsible for malaria. To date, Plasmodium falciparum has shown multi-drug resistance, particularly in Thailand, Myanmar and Malaysia. The aim of the study is to screen the plant extracts that can effectively inhibit P. falciparum 3D7, a common lab strain malaria parasite. Nine plants were collected and processed through maceration using hexane, chloroform and ethanol, resulting in 24 crude plant extracts. Of these, extracts from Artabotrys crassifolius, Pericampylus glacus and Leuconotis eugeniifolia showed promising antiplasmodial activities at IC50 of 15.32 to 39.75 µg/mL in a modified schizont maturation assay. Further studies are warranted to explore its efficacies and lead compounds of these three plant extracts for the development of antiplasmodial drugs.