In Indonesia, a country with largest Muslim population in the world, the necessity to study the artificial hip joint which allows Muslim patients with total hip replacement to have normal Salat becomes important issues. This paper discusses the effect of impingement which occurs during one of the Salat movements. i.e. last tashahhud sitting motion. An artificial hip joint model, proposed by previous researcher from developed country, is simulated using finite element analysis to perform last tashahhud sitting motion. The result shows that impingement occurs and causes the plastic deformations and plastic strains in the acetabular liner component which is manufactured from UHMWPE material. The repetition of Salat movement induces repeated impingements and higher plastic deformation. It experiences dimensional change in the liner lip and has a potency to cause clinical failure of total hip replacement. A new design of the artificial hip joint is required to be proposed to avoid the repeated impingement and deformations.

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The wear of hip prosthesis due to applied load and sliding distance during the patient's daily activity cannot be avoided. Wear causes osteolysis or metallosis due to the wear debris produced by the wear process. Several methods were used to reduce wear in metal-on-metal hip prostheses. One of the efforts performed to reduce wear was the differential-hardness concept. Based on the literature, the fine surface roughness of the femoral head are the reason why the hip prosthesis with differential-hardness reduces wear. Besides, the differential-hardness will contribute to the difference of modulus elasticity then influenced the contact stress on the surface contact. According to Archard's wear law, wear on the material pair is affected by contact stress. Therefore, the analysis of contact stress on the hip prosthesis with differential-hardness is important to investigate. The investigation performed by the static contact of two-dimensional axisymmetric with frictionless by using finite element simulation. The simulated models are the alumina vs. alumina, alumina vs. SS316L, CoCr vs. CoCr, CoCr vs. SS316L, and SS316L vs. UHMWPE. The purpose of this study is to determine the contact stress on the surface contact due to differential-hardness of the femoral head and cup. The results of simulations show that the differential-hardness marked by differences in the modulus of elasticity can reduce the contact stress on the surface contact if compare with the similar hardness.

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Patellar tendon rupture after total knee arthroplasty is a rare, but often catastrophic complication. In addition, infection is also a dreaded complication after total knee arthroplasty. We report an 84-year-old female that has late infected total knee arthroplasty with patellar tendon rupture treated with resection arthroplasty and then subsequent arthrodesis with retrograde intramedullary nail. Objective: Periprosthetic joint infection (PJI) of the hip due to methicillin-resistant bacteria is difficult to treat and remain a challenge for arthroplasty surgeon. Methods: Retrospective review was done to the patients who received two-stage revisions with antibiotic loaded cement-spacer for PJI of the hip between January 2010 to June 2015. We found 65 patients (65 hips) with positive culture findings. Eight patients were lost to followup and excluded from the study. Among the rest of the 57 patients, methicillin-resistant infection (MR Group) was found in 28 cases. For comparison, we also evaluated the 29 other cases that caused by other pathogen (Non-Methicillin resistant group/Non-MR group). We compared all of the relevant medical records and the treatment outcomes between the two groups. Results: The mean of follow-up period was 33.7 months in the methicillin-resistant group and 28.4 months in the nonmethicillin-resistant group (p = 0.27). The causal pathogens in the methicillin-resistant group were: Methicillin-resistant Staphylococcus aureus (MRSA) in 10 cases, Methicillin-resistant Staphylococcus epidermidis (MRSE) in 16 cases and Methicillin-resistant coagulase-negative Staphylococcus (MRCNS) in 2 cases. The reimplantation rate was 92.8% and 89.6% in the methicillin-resistant and nonmethicillinresistant groups, respectively (p= 0.66). The rates of recurrent infection after reimplantation were 23.1% (6/26) in the methicillin-resistant group and 7.6% (2/26) in the nonmethicillinresistant group (p= 0.12). The overall infection control rate was 71.4% (20/28) and 89.6% (26/29) in the methicillin-resistant and nonmethicillin-resistant groups, respectively (p = 0.08). Both group showed comparable baseline data on mean age, BMI, gender distribution, preoperative ESR/CRP/WBC and comorbidities. Conclusion: Two-stage revision still resulted a higher recurrency rate and lower infection control rate for the treatment of periprosthetic joint infection (PJI) of the hip due to methicillin-resistant infection compared to nonmethicillin-resistant infection.