Keerati Chareancholvanich

Prosthetic joint infection (PJI) is a major complication of total hip and total knee arthroplasty (THA, TKA). Although mycobacteria are rarely the causative pathogens, it is important to recognize and treat them differently from non-mycobacterial infections. This study aimed to compare the clinical characteristics, associated factors and long-term outcomes of mycobacterial and non-mycobacterial PJI. We conducted a retrospective case-control study of patients aged ≥18 years who were diagnosed with PJI of the hip or knee at Siriraj Hospital from January 2000 to December 2012. Patient characteristics, clinical data, treatments and outcomes were evaluated. A total of 178 patients were included, among whom 162 had non-mycobacterial PJI and 16 had mycobacterial PJI. Rapidly growing mycobacteria (RGM) (11) and M. tuberculosis (MTB) (5) were the causative pathogens of mycobacterial PJI. PJI duration and time until onset were significantly different between mycobacterial and non-mycobacterial PJI. Infection within 90 days of arthroplasty was significantly associated with RGM infection (OR 21.86; 95% CI 4.25–112.30; p < .001). Implant removal was associated with improved favorable outcomes at 6 months (OR 5.96; 95% CI 1.88–18.88; p < .01) and 12 months (OR 3.96; 95% CI 1.15–13.71; p = .03) after the infection. RGM were the major pathogens of early onset PJI after THA and TKA. Both a high clinical index of suspicion and mycobacterial cultures are recommended when medically managing PJI with negative cultures or non-response to antibiotics. Removal of infected implants was associated with favorable outcomes.

Patient position is an important factor which can affect the accuracy of patellar height ratio measurement. Varying degree of knee flexion angles and action of quadriceps muscle while supine or standing positions are the most concerning factors. Forty healthy subjects had radiographs taken of their knees at 0°, 30°, and 60° of flexion in the supine (non-weight-bearing) and standing (weight-bearing) positions. Patellar height was assessed by five different measurement methods including Insall-Salvati (IS), Modified Insall-Salvati (MIS), Caton-Deschamps (CD), Blackburne-Peel (BP), and Knee triangular ratio (KT). The mean and standard deviation (SD) in the supine/standing position of each method were IS 1.0 (0.1)/1.05 (0.1), MIS 1.6 (0.2)/1.8 (0.3), CD 1.0 (0.2)/1.2 (0.2), BP 0.9 (0.2)/1.0(0.2), and KT 1(0.1)/1(0.1). Significant differences were found between supine and standing positions using all of the methods except for KT ratio. Comparisons between the various knee flexion angles were found to be statistically significant by most of the measurement methods, although the differences between the means were less than their SD. Quadriceps action had a significant influence on the mean values obtained by the MIS, CD, and BP methods. In clinical practice, interpretation for patella alta or patella baja of these measurement methods should be normalized according to the patient position. Varying the degree of knee flexion did not produce clinically important effects in any of the five patellar height measurement methods.

Purpose: High tibial osteotomy (HTO) is a surgical procedure used to correct abnormal mechanical loading of the knee joint; additionally, intra‐articular hyaluronic acid injections have been shown to restore the viscoelastic properties of synovial fluid and balance abnormal biochemical processes. It was hypothesized that combining HTO with intra‐articular hyaluronic acid injections would have benefit to improve the cartilage volume of knee joints.Methods: Forty patients with medial compartment knee osteoarthritis (OA) were randomly placed into 1 of 2 groups. The study group (n = 20) received 2 cycles (at 6‐month intervals) of 5 weekly intra‐articular hyaluronic acid injections after HTO operation. The control group (n = 20) did not receive any intra‐articular injections after HTO surgery. Cartilage volume (primary outcome) was assessed by magnetic resonance imaging (MRI) pre‐operatively and 1 year post‐operatively. Treatment efficacy (secondary outcomes) was evaluated with the Western Ontario and McMaster Universities OA Index (WOMAC) and by the comparison of the total rescue medication (paracetamol/diclofenac) used (weeks 6, 12, 24, 48).Results: MRI studies showed a significant increase in total cartilage volume (p = 0.033), lateral femoral cartilage volume (p = 0.044) and lateral tibial cartilage volume (p = 0.027) in the study group. Cartilage volume loss was detected at the lateral tibial plateau in the control group. There were significant improvements after surgery in both groups for all subscales of WOMAC scores (p < 0.001) compared to the baseline. However, no difference was found between the two groups. The study group had significantly lower amounts of diclofenac consumption (p = 0.017).Conclusion: Based on the findings of the present study, intra‐articular hyaluronic acid injections may be beneficial for increasing total cartilage volume and preventing the loss of lateral tibiofemoral joint cartilage after HTO.Level of evidence: Therapeutic study, Level I.

Background: Medial proximal tibial angle (MPTA) is the commonly used angle, which is simply measured from the knee radiographs. It can determine the correction angle in medial opening wedge high tibial osteotomy (MOWHTO). The hypothesis of our study is that post-osteotomy MPTA can predict the change in correction angle, and we aimed to determine the optimal MPTA with which to prevent recurrent varus deformity after MOWHTO. Materials and Methods: Between January 2002 and April 2010, radiographs of 59 patients, who underwent 71 MOWHTOs using the locking-compression osteotomy plates without bone grafts, were evaluated for the change of the MPTA. The MPTA was measured preoperatively and one and twelve months postoperatively. The changes of MPTA between one and twelve months were classified into valgus, stable, and varus change. The predicting factors were analyzed using analysis of variance (ANOVA) and Bonferroni multiple comparisons. The receiver operating characteristic (ROC) curve was used to find out the cut off point for preventing the recurrent varus deformity. Results: The overall preoperative, and one and twelve month postoperative MPTA values were 84.4 ± 2.4°, 97.2 ± 4.1°, and 96.3 ± 3.6°, respectively. Between one and twelve months, 39 knees displayed reduced varus change (−2.8 ± 2.1°), 18 knees displayed no change, and 14 knees displayed a greater valgus change (+2.9 ± 2.1°). The best factor for predicting these changes was the one month MPTA value (P = 0.006). By using the ROC curve, a one month MPTA of 95° was analyzed as the cut off point for preventing the recurrent varus deformity. With MPTA ≥95°, 92.3% of the osteotomies exhibited stable or varus change and 7.7% exhibited valgus change. However, with MPTA P < 0.001, odds ratio = 13.3). Conclusion: The postoperative MPTA can be used to predict the change in correction angle and an MPTA of at least 95° is the crucial angle with which to prevent recurrent varus deformity.

Antibiotic prophylaxis is used in all patient underwent total knee arthroplasty to prevent post operative infection which produced poor outcome. The suitable drug should be safe and good efficacy. To study safety and efficacy of fosfomicin and cefuroxime as antibiotic prophylaxis for total knee arthroplasty. The control trial was performed to find out efficacy and safety of fosfomycin as an antibiotic prophylaxis comparing to cefuroxime. There were 112 patients, 14 male and 98 female, with their ages ranged between 57 and 86 years. They were randomly divided into two groups, the fosfomycin group, 56 patients and the cefuroxime group, 56 patients. All patients underwent elective knee arthroplasty by the authors. The scheduled antibiotics were given perioperatively for 24 hours and all patients were followed-up for 6 months. Physical examination, skin temperature of the operated knee, radiograph and blood tests were carried out in the patients to monitor post operative infection, renal and liver disturbance. One patient in the cefuroxime group had local wound infection which responded well to local treatment and administration of antibiotics. No patients had post operative infection at the 6 months follow-up. No patients had any complication and none had renal and liver function disturbance during the follow-up. Comparing to cefuroxime,fosfomycin is safe and effective for the use as antibiotic prophylaxis in knee arthroplasty.

Total knee arthroplasty (TKA) is a common procedure that has a risk of significant blood loss and blood transfusion, and carries a substantial risk for immunologic reactions and disease transmission. Drain clamping is a popular method that is applied to reduce blood loss after TKA. However, the clamping protocol remains controversial. Therefore, we established a new protocol, 3-h interval clamping, and compared the bleeding control efficacy of this protocol following TKA with the non-clamping technique.