Pedro Hinarejos

The use of erythromycin and colistin-loaded cement in total knee arthroplasty does not reduce the incidence of infection: a prospective randomized study in 3000 knees.

BACKGROUND The use of antibiotic-loaded cement is believed to prevent infection in primary total knee arthroplasty, but there is a lack of randomized studies to support this concept. The aim of this study was to evaluate the use of an antibiotic-loaded cement to reduce the infection rate in primary total knee arthroplasty. METHODS This is a prospective randomized study with 2948 cemented total knee arthroplasties, in which bone cement without antibiotic was used in 1465 knees (the control group) and a bone cement loaded with erythromycin and colistin was used in 1483 knees (the study group). All patients received the same systemic prophylactic antibiotics. The patients were followed for a minimum of twelve months. The rate of infection was analyzed according to the criteria of the Centers for Disease Control and Prevention. RESULTS The rate of deep infection (1.4% in the control group and 1.35% in the study group; p = 0.96) and the rate of superficial infection (1.2% and 1.8%, respectively; p = 0.53) were similar in both groups. The factors related to a higher rate of deep infection in a multivariate analysis were male sex and an operating time of >125 minutes. CONCLUSIONS The use of erythromycin and colistin-loaded bone cement in total knee arthroplasty did not lead to a decrease in the rate of infection when systemic prophylactic antibiotics were used, a finding that suggests that the use of antibiotic-loaded bone cement would not be indicated in the general population. Further research is needed to assess whether its use is recommended for patients with a higher risk of infection.

Influence of Depression on Total Knee Arthroplasty Outcomes

It is not clear whether indicating TKA-surgery is advisable in depressed patients. A prospective cohort of 716 patients undergoing TKA was designed. SF36, KSS, WOMAC and VAS plus 2 satisfaction questions were evaluated. There were 2 groups: 200 patients were depressed and 516 were not. Preoperative/postoperative results show better scores for non-depressed patients on almost every sub-scale. Nevertheless, net change results (improvement) were quite similar: 65.74 improvement in depressed-KSS and 74.58 in non-depressed (P=0.049); 8.93 net change in depressed-Physical Composite Score and 11.84 in non-depressed (P=0.003); 2.38 in depressed-Mental Composite Score and -0.61 in non-depressed (P=0.024). Depressed patients obtained great improvement from preoperative at one-year follow-up and even greater than non-depressed patients in some domains. Moreover, satisfaction was similar. Therefore, TKA can be recommended to depressed patients.

Use of antibiotic-loaded cement in total knee arthroplasty

Bone cement has the capacity to release antibiotic molecules if any antibiotic is included in it, and these elution properties are improved as cement porosity is increased. In vitro studies have shown high local antibiotic concentration for many hours or few days after its use. Antibiotic loaded bone cement (ALBC) is helpful when treating an infection in total knee arthroplasty (TKA) revision surgery. The purpose of this paper was to review the evidence for the routine use of ALBC in TKA in the literature, its pros and cons. Many authors have recommended the use of ALBC also in primary TKA for infection prophylaxis, but the evidence based on data from National Registries, randomized clinical trials and meta-analysis suggest a protective effect of ALBC against infection when used in hips, but not (or only mild) in knees. A possible explanation to this finding is that the duration and quantity of locally elevated antibiotic levels after surgery are smaller in TKA, due to the smaller amount of cement used for fixation in TKA-only a layer in the bone surface. There are some concerns about the routine use of ALBC in primary TKA as prophylaxis against infection: Firstly, there is a risk of hypersensivity or toxicity even when the chance is highly improbable. Secondly, there is a reduction in the mechanical properties of the cement, but this can be probably neglected if the antibiotic is used in low doses, not more than 1 g per 40 g cement package. Another significant concern is the increased economic cost, which could be overlooked if there were enough savings in treating fewer prosthetic infections. Finally, there is also a risk of selection of antibiotic-resistant strains of bacteria and this could be the main concern. If used, the choice of the antibiotic mixed in ALBC should consider microbiological aspects (broad antimicrobial spectrum and low rate of resistant bacteria), physical and chemical aspects (thermal stability, high water solubility), pharmacological characteristics (low risk to allergic reactions or toxicity) and economic aspects (not too expensive). The most commonly used antibiotics in ALBC are gentamicin, tobramycin and vancomycin. In conclusion, there is a paucity of randomized clinical trials in the use of ALBC in primary TKAs and the actual evidence of the effect of ALBC in reducing the risk of infection is insufficient. This, in addition to concerns about patient safety, risks of increase in the antibiotic resistance of microorganisms and the increase in costs in the procedure, lead us to recommend a cautious use of ALBC, perhaps only in high-risk patients (immunocompromised, morbidly obese, diabetic and patients with previous history of fracture or infection around the knee) unless the benefits of ALBC use were fully proven. Meanwhile, the rigorous use of peri-operative prophylactic systemic antibiotics and adoption of efficient antiseptic procedures and improved surgical techniques must be considered the gold standard in infection prevention in TKA surgery.

Highly crosslinked polyethylene does not reduce the wear in total knee arthroplasty: in vivo study of particles in synovial fluid.

The aim was to assess if the reduction in polyethylene wear with highly crosslinked polyethylene suggested by studies with knee simulators is confirmed in patients with a knee arthroplasty. The use of a conventional or a highly crosslinked polyethylene was randomly assigned intraoperatively. Twelve months after surgery a knee arthrocentesis was performed and the synovial fluid of 17 patients in each group was studied analysing the number, size and shape of the polyethylene particles by scanning electron microscope. We found no significant differences in the concentration, size or morphology of polyethylene particles between groups. The great variability in the number of particles between individuals suggests that in vivo polyethylene wear depends on many factors and probably the type of polyethylene is not the most significant.

Correlation Study Between KSS, WOMAC and SF-36 Scores in Patients Undergoing Total Knee Arthroplasty in a Spanish Speaking Population

The aim of this study was to determine whether it is necessary to use the KSS, WOMAC and SF-36 scales in a Spanish speaking population. These 3 questionnaires were administered to 1000 consecutive patients in the TKA preoperative period. Pearsons correlation coefficient and coefficient of determination were obtained. 196 patients were excluded. A poor correlation was obtained comparing the different items of the different scores with each other. Only in 3 out of different comparisons performed was a Pearsons correlation r>0.5 obtained. The worst results were obtained comparing the two knee specific tests (SF-36 vs WOMAC) and the best ones comparing SF-36 and WOMAC scores. Based on these results, the use of the three tests in the TKA preoperative period is recommended in a Spanish speaking population.

Long Term Follow-Up of Successfully Treated Superficial Wound Infections Following TKA

The relevance of wound complications in association with acute prosthetic joint infection (PJI) is well known. However, whether a successfully treated superficial infection can result in a chronic deep infection remains unclear. The aim of this study was to determine the prevalence, treatment and late complications of superficial wound infections following TKA. In a 3000 TKA prospective cohort, 45 superficial infections were diagnosed and treated successfully with antibiotic therapy along with or without surgical debridement. None of the cases developed deep chronic PJI at 70 months of follow-up. Three cases were in need of a TKA exchange due to aseptic loosening. A successfully treated superficial wound infection does not result in a chronic deep TKA infection.

Comparison of quality of life between elderly patients undergoing TKA.

The purpose of this study was to compare the short-term changes in quality of life for patients younger than 80 years with those 80 years and older undergoing total knee arthroplasty (TKA). It was hypothesized that patients 80 years and older had a similar quality of life after TKA compared with those younger than 80 years.All consecutive patients undergoing primary TKA were enrolled in this prospective, comparative, prognostic (level I evidence) study and were stratified into 2 groups based on their age (younger than 80 years and 80 years and older). Data on quality of life assessed using the Short Form 36 health survey were obtained preoperatively and 1 year postoperatively (short-term follow-up) and were compared between groups. A total of 328 (83.89%) patients younger than 80 years (mean age, 70.7 years) and 63 (16.11%) patients 80 years and older (mean age, 82.1 years) were included. No significant differences in preoperative quality of life were observed between groups. Postoperative physical function, vitality, social function, and physical component summary were lower in patients 80 years and older. Older patients had a lower difference between pre- and postoperative values in Short Form 36 physical function and role-emotional scores.Patients 80 years and older had a similar improvement in quality of life 1 year after TKA compared with patients younger than 80 years. Therefore, changes in quality of life justify TKA as a treatment option for elderly patients with end-stage knee osteoarthritis.

Fibrosarcoma at the site of a metallic fixation of the tibia--a case report and literature review

treatment was closed in 5 cases with minimal displacement and surgical in the remaining 4 with a severe displacement. The mechanism of this juvenile fracture is well known; the keystone is the peculiar closure pattern of the distal tibial physis, which makes the lateral corner a weakened portion for a period of 18 months until complete closure occurs (Rang 1974). Injuries with the foot in external rotation and extension lead to avulsion of this physeal portion, due to excessive tension of the tibio-fibular ligament. In displacements exceeding 2 mm with a rotation of the fragment, open reduction and internal fixation have been suggested to obtain articular congruence (Stefanich and Lozman 1986, Mariani and Perrone 1998). Schlesinger and Wedge (1993) described percutaneous fixation of the displaced fragment. As to our patient, we were concerned about the quality of bone in the dislocated fragment, hence the possibility of obtaining good osteosynthesis with an anatomical reduction. The fragment was moderately porotic, but reduction and stable synthesis were possible. Another risk that had to be taken into account was avascular necrosis (AVN) of the fragment, which is theoretically increased by a delayed diagnosis and treatment. We found no sign of necrosis when we removed the screw and at the final follow-up, the boy had no symptoms.

Sealing of the intramedullar femoral canal in a TKA does not reduce postoperative blood loss: A randomized prospective study

BACKGROUND Sealing of the femoral canal, usually with autologous bone, is a surgical procedure that is often performed during TKA surgery to decrease blood loss in the postoperative period. However, evidence as to the effectiveness of this surgical procedure is not conclusive. The objective of this study was to assess the effectiveness of this surgical action in reducing postoperative blood loss and the blood transfusion rate. METHODS A randomized prospective study that included 201 TKAs divided into three groups (67 in each one) was carried out. The three groups were; A) bone graft sealing, B) cement sealing and C) unsealed canal. All groups were comparable with regard to pre and intra-operative data. The haemoglobin decrease at 2, 24 and 72 h was compared to the preoperative haemoglobin value. Subsequently, blood drainage at 12 and 24h and the rate of blood transfusion were also assessed. The different complications that arose were reported. RESULTS No statistical differences were obtained with regard to blood drainage at 12h (p=0.102) and 24h (p=0.542), the haemoglobin value decrease at 72 h (p=0.95) and the number of blood transfusions (p=0.597) in the three groups studied. CONCLUSION There was no significant difference, whether sealing the femoral canal with a bone graft, cement or when it was left unsealed, in decreasing blood loss or blood transfusion requirements in the postoperative period. LEVEL OF EVIDENCE Therapeutic type I.

Managing septic arthritis after knee ligament reconstruction.

PurposeJoint infection after anterior cruciate ligament (ACL) reconstruction is uncommon but has potentially serious consequences for the graft and articular cartilage. Most recently published series are in agreement that an urgent arthroscopic washout and antibiotic treatment are mandatory to preserve both graft and cartilage. However, several questions have not as yet been touched upon.MethodsWe performed a literature review to assess the most interesting series published about this issue.ResultsIn this review, a management protocol is first presented that discusses the different diagnostic parameters to consider and surgical and antibiotic treatment suggested according to the literature. Outcomes published in different series are also discussed.