Andreas Roth

Diagnostic work-up strategy for periprosthetic joint infections after total hip and knee arthroplasty: a 12-year experience on 320 consecutive cases

BackgroundElective knee and hip arthroplasty is followed by infections in currently about 0.5–2.0 % of cases – a figure which is on the increase due to the rise in primary implants. Correct diagnosis early on is essential so that appropriate therapy can be administered. This work presents a retrospective analysis of the diagnoses of patients suffering infections after total hip or knee arthroplasty.Methods320 patients with prosthetic joint infection (PJI) following knee or hip arthroplasty were identified. They comprised a) 172 patients with an infection after total hip arthroplasty (THA): 56 % females (n = 96) and 44 % males (n = 76) with a mean age of 70.9 (39–92) years; and 148 patients with an infection after total knee arthroplasty (TKA): 55 % females (n = 82) and 45 % males (n = 66) with a mean age of 70.7 (15–87) years.ResultsAlthough significantly more TKA than THA patients reported pain, erythema, a burning sensation and swelling, no differences between the two groups were observed with respect to dysfunction, fever or fatigue. However, significant differences were noted in the diagnosis of loosening (THA 55 %, TKA 31 %, p < 0.001) and suspected infection using conventional X-rays (THA 61 %, TKA 29 %, p < 0.001). FDG-PET-CT produced very good results in nearly 95 % of cases. There were no differences between THA and TKA patients regarding levels of inflammation markers. Histological evaluation proved to be significantly better than microbiological analysis.SummaryThe clinical picture may be non-specific and not show typical inflammatory symptoms for a long time, particularly in PJI of the hip. As imaging only provides reliable conclusions after the symptoms have persisted for a long time, morphological imaging is not suitable for the detection of early infections. FDG-PT-CT proved to be the most successful technique and is likely to be used more frequently in future. Nevertheless, there are currently no laboratory parameters which are suitable for the reliable primary diagnosis of PJI. Diagnosis requires arthrocentesis, and the fluid obtained should always be examined both microbiologically and histologically.

Peer-assisted teaching student tutors as examiners in an orthopedic surgery OSCE station - pros and cons.

Background: The OSCE (objective structured clinical examination) is composed of oral and practical examination in order to examine students’ abilities to imply clinical examination techniques and to interact with patients. The examiners for this procedure can be either lecturers or peers. The aim of this work is to evaluate the peer-assisted teaching student tutors as examiners in an orthopedic surgery OSCE station. Methods: We analyzed the OSCE data from 2013 to 2015. During this period over 300 medical students were examined each year. An evaluation was conducted at an orthopedic station and examined by peer students to assess the advantages and disadvantages of peer-assisted teaching student tutors as examiners. Results: We have noticed that student peers are more flexible regarding their schedule and they have been well trained for OSCE. Concerning the economic aspects, student peers are clearly of major economic advantage. Disadvantages were not reported in our study probably because peers were well trained and the checklists are monitored regularly. Conclusion: Student peers in OSCE are of major advantage due to their flexible time schedule and relatively low costs. They must be well trained and the checklists are to be monitored regularly. Our study shows that peer tutor examiners conducted the examination as competent as lecture examiners. However, legal restrictions on the employment of students should be considered.

A new classification of TKA periprosthetic femur fractures considering the implant type

BackgroundThe treatment aims of periprosthetic fractures (PPF) of the distal femur are a gentle stabilization, an early load-bearing capacity and a rapid postoperative mobilization of the affected patients. For the therapy planning of PPF a standardized classification is necessary which leads to a clear and safe therapy recommendation. Despite different established classifications, there is none that includes the types of prosthesis used in the assessment. For this purpose, the objective of this work is to create a new more extensive fracture and implant-related classification of periprosthetic fractures of the distal femur based on available classifications which allows distinct therapeutic recommendations.MethodsIn a retrospective analysis all patients who were treated in the University Hospital Leipzig from 2010 to 2016 due to a distal femur fracture with total knee arthroplasty (TKA) were established. To create an implant-associated classification the cases were discussed in a panel of experienced orthopaedists and well-practiced traumatologists with a great knowledge in the field of endoprosthetics and fracture care. In this context, two experienced surgeons classified 55 consecutive fractures according to Su et al., Lewis and Rorabeck and by the new created classification. In this regard, the interobserver reliability was determined for two independent raters in terms of Cohen Kappa.ResultsOn the basis of the most widely recognized classifications of Su et al. as well as Lewis and Rorabeck, we established an implant-dependent classification for PPF of the distal femur. In accordance with the two stated classifications four fracture types were created and defined. Moreover, the four most frequent prosthesis types were integrated. Finally, a new classification with 16 subtypes was generated based on four types of fracture and four types of prosthesis. Considering all cases the presented implant-associated classification (κ = 0.74) showed a considerably higher interobserver reliability compared to the other classifications of Su et al. (κ = 0.39) as well as Lewis and Rorabeck (κ = 0.31). Excluding the cases which were only assessable by the new classification, it still shows a higher interobserver reliability (κ = 0.70) than the other ones (κ = 0.63 or κ = 0.45).ConclusionsThe new classification system for PPF of the distal femur following TKA considers fracture location and implant type. It is easy to use, shows agood interobserver reliability and allows conclusions to be drawn on treatment recommendations. Moreover, further studies on the evaluation of the classification are necessary and planned.

Outcome of total knee replacement following explantation and cemented spacer therapy.

Background: Infection after total knee replacement (TKR) is one of the serious complications which must be pursued with a very effective therapeutic concept. In most cases this means revision arthroplasty, in which one-setting and two-setting procedures are distinguished. Healing of infection is the conditio sine qua non for re-implantation. This retrospective work presents an assessment of the success rate after a two-setting revision arthroplasty of the knee following periprosthetic infection. It further considers drawing conclusions concerning the optimal timing of re-implantation. Patients and methods: A total of 34 patients have been enclosed in this study from September 2005 to December 2013. 35 re-implantations were carried out following explantation of total knee and implantation of cemented spacer. The patient’s group comprised of 53% (18) males and 47% (16) females. The average age at re-implantation time was 72.2 years (ranging from 54 to 85 years). We particularly evaluated the microbial spectrum, the interval between explantation and re-implantation, the number of surgeries that were necessary prior to re-implantation as well as the postoperative course. Results: We reported 31.4% (11) reinfections following re-implantation surgeries. The number of the reinfections declined with increasing time interval between explantation and re-implantation. Patients who developed reinfections were operated on (re-implantation) after an average of 4.47 months. Those patients with uncomplicated course were operated on (re-implantation) after an average of 6.79 months. Nevertheless, we noticed no essential differences in outcome with regard to the number of surgeries carried out prior to re-implantation. Mobile spacers proved better outcome than temporary arthrodesis with intramedullary fixation. Conclusion: No uniform strategy of treatment exists after peri-prosthetic infections. In particular, no optimal timing can be stated concerning re-implantation. Our data point out to the fact that a longer time interval between explantation and re-implantation reduces the rate of reinfection. From our point of view, the optimal timing for re-implantation depends on various specific factors and therefore it should be defined individually.

The significance of the vitamin D metabolism in the development of periprosthetic infections after THA and TKA: a prospective matched-pair analysis of 240 patients

Background The importance of the vitamin D homeostasis in infections is already known. However, its significance in periprosthetic infections (PPIs) after total hip arthroplasty and total knee arthroplasty is largely unexplored. The aim of the study is to precisely analyze the vitamin D balance in patients with PPIs after total hip arthroplasty and total knee arthroplasty. Here, cases with primary endoprosthesis implants and aseptic loosening are used as comparison groups. Materials and methods In this prospective matched-pair analysis, patients with PPI at the hip and knee joints were included in the study group (SG). The control groups (CGs) consisted of patients with primary implants (CG I) and who underwent replacement surgery due to aseptic loosening (CG II). In addition to 25 OH vitamin D3 and calcium, bone mineral and protein parameters were determined. An osteoporosis-specific questionnaire was collected. Results There are no significant differences in the 25 OH-vitamin D levels between the SG (17.9±8.9) and both CGs (CG I: 16.8±6.90; CG II: 19.7±7.90). However, compared with the SG, significantly higher levels of calcium (Ca) and bone-specific alkaline phosphatase were found in both CGs in comparison with the SG. Significantly lower values concerning the protein balance in PPI were conspicuous. Acute PPI showed a significant reduction in 25 OH vitamin D3 compared with chronic infections (8.3±5.98 vs 21.6±8.40, P=0.002). Calcium and protein balance were also significantly reduced in acute PPIs. Conclusion Acute PPIs of the hip and knee joints show a significantly reduced calcium and 25 OH vitamin D3 levels as well as lowered proteins (albumin and total protein) compared with chronic infections as well as primary endoprostheses and aseptic replacement operations. Substitution of vitamin D3 and calcium with simultaneous adaptation of the protein balance is recommended in all PPIs, especially in the acute PPI.

Zusammenführung von Orthopädie und Unfallchirurgie – das Leipziger Modell

Die Etablierung und Umsetzung des gemeinsamen Facharztes Orthopadie und Unfallchirurgie in den Alltag war und ist eine Herausforderung fur alle Beteiligten. Fur eine Umsetzung auf Augenhohe wurden in den letzten Jahren grose Anstrengungen der Fachgesellschaften, der Berufsverbande und aller beteiligten Akteure unternommen. Grundsatzlich und fur die Umsetzung vor Ort gibt es nicht das eine Erfolgsrezept. Die Umsetzung muss unter Berucksichtigung der ortlich-strukturellen, fachlichen und historischen Gegebenheiten mit Bedacht erfolgen. Deshalb mochten die Autoren uber den Weg des Leipziger Universitatsklinikums zu einer gemeinsamen Klinik fur Orthopadie, Unfallchirurgie und Plastische Chirurgie und die ersten 3 Jahre Erfahrung und Weiterentwicklung seit ihrer Etablierung berichten.

Bipolar hip arthroplasty as salvage treatment for loosening of the acetabular cup with significant bone defects

Introduction: Revision arthroplasty of the hip is becoming increasingly important in recent years. Early primary arthroplasty and longer life expectancy of the patients increases the number of revision surgery. Revision surgery of hip arthroplasty is major surgery for the patients, especially the elderly, with significant risks concerning the general condition of the patient. The aim of this work is to evaluate the outcome of bipolar hip arthroplasty as a salvage procedure for treatment of loosening of the acetabular cup with significant acetabular bone defects after total hip replacement (THR) in multi-morbid patients. Patients and methods: During the period from January 1st 2007 to December 31st 2011 19 revision hip surgeries were performed in 19 patients, in which the loosened acetabular cup was replaced by a bipolar head. The examined patient group consisted exclusively of female patients with an average of 75 years. The predominant diagnosis was “aseptic loosening” (84.2%). All patients in our study were multi-morbid. We decided to resort to bipolar hip arthroplasty due to the compromised general condition of patients and the major acetabular bone defects, which were confirmed intraoperatively. The postoperative follow-up ranged from 0.5 to 67 months (average 19.1 months). Results: Evaluation of the modified Harris Hip Score showed an overall improvement of the function of the hip joint after surgery of approximately 45%. Surgery was less time consuming and thus adequate for patients with significantly poor general health condition. We noticed different complications in a significant amount of patients (68.4%). The most common complication encountered was the proximal migration of the bipolar head. The rate of revision following the use of bipolar hip arthroplasty in revision surgery of the hip in our patients was high (21%). Despite the high number of complications reported in our study, we have noticed significant improvement of hip joint function as well as subjective pain relief in the majority of patients. We clearly achieved clinically satisfactory results in 14 patients. Conclusion: Bipolar hip arthroplasty is by no means to be regarded as standard procedure in revision surgery of THR. It provides an option or salvage procedure for patients with poor general condition in whom the quickest possible surgical intervention preserving mobility is required. This is particularly true for multi-morbid patients in whom sufficient acetabular fixation is not possible.

Infektionen von Hüft- und Knieendoprothesen@@@Infections of hip and knee endoprostheses: Erregerspektrum und die Rolle multiresistenter Bakterien@@@Spectrum of pathogens and the role of multiresistant bacteria

BACKGROUND Because of the rise in primary implantations in elective knee and hip arthroplasty, the number of complications, particularly due to prosthetic infections has increased. Partly due to multimorbidities, an increase in geriatric patients and often unnecessary use of antibiotics, a change in the spectrum of bacteria with an increase in multi-drug resistant pathogens is to be expected. For physicians this creates not only new medical and economic but also sociopolitical challenges. QUESTION Has the spectrum of bacteria in prosthetic joint infections after total hip arthroplasty (THA) and total knee arthroplasty (TKA) changed during the 12-year period 2001-2012 in our hospital and what role do multi-drug resistant bacteria play? INVESTIGATION COLLECTIVE A total of 320 patients with prosthetic joint infections (PJI) following TKA or THA could be identified and were included in this study. The sample consisted of 172 patients with an infection after THA (56 % females n = 96 and 44 % males n = 76) with a mean age of 70.9 years (range 39-92 years) and 148 patients with an infection after TKA (55 % females n = 82 and 45 % males n = 66) with a mean age of 70.7 years (range 15-87 years). The bacteria detected and the development over the course of time were evaluated. RESULTS An increase was found in the occurrence of coagulase negative staphylococci (CNS), in particular Staphylococcus epidermidis (2001-2003 n = 10 and 2010-2012 n = 27). The proportion of oxacillin and methicillin-resistant Staphylococcus epidermidis (MRSE) was also found to increase (0 % in 2001-2003 and 74 % in 2010-2012). A substantial increase in methicillin-resistant Staphylococcus aureus (MRSA) infections could not be found and there was a tendency towards reduction in the total number of Staphylococcus aureus infections. A total of five extended spectrum beta-lactamase (ESBL)-producing bacteria were isolated. CONCLUSION The spectrum of bacteria has only slightly changed over the years from 2001 to 2012, whereby an increase was only found in the number of CNS infections. Multi-drug resistant bacteria, in particular MRSE have increased. The changes in MRSE found in this study do not appear to warrant a general rethinking of antibiotic prophylaxis.

Infektionen von Hüft- und KnieendoprothesenInfections of hip and knee endoprostheses

BACKGROUND Because of the rise in primary implantations in elective knee and hip arthroplasty, the number of complications, particularly due to prosthetic infections has increased. Partly due to multimorbidities, an increase in geriatric patients and often unnecessary use of antibiotics, a change in the spectrum of bacteria with an increase in multi-drug resistant pathogens is to be expected. For physicians this creates not only new medical and economic but also sociopolitical challenges. QUESTION Has the spectrum of bacteria in prosthetic joint infections after total hip arthroplasty (THA) and total knee arthroplasty (TKA) changed during the 12-year period 2001-2012 in our hospital and what role do multi-drug resistant bacteria play? INVESTIGATION COLLECTIVE A total of 320 patients with prosthetic joint infections (PJI) following TKA or THA could be identified and were included in this study. The sample consisted of 172 patients with an infection after THA (56 % females n = 96 and 44 % males n = 76) with a mean age of 70.9 years (range 39-92 years) and 148 patients with an infection after TKA (55 % females n = 82 and 45 % males n = 66) with a mean age of 70.7 years (range 15-87 years). The bacteria detected and the development over the course of time were evaluated. RESULTS An increase was found in the occurrence of coagulase negative staphylococci (CNS), in particular Staphylococcus epidermidis (2001-2003 n = 10 and 2010-2012 n = 27). The proportion of oxacillin and methicillin-resistant Staphylococcus epidermidis (MRSE) was also found to increase (0 % in 2001-2003 and 74 % in 2010-2012). A substantial increase in methicillin-resistant Staphylococcus aureus (MRSA) infections could not be found and there was a tendency towards reduction in the total number of Staphylococcus aureus infections. A total of five extended spectrum beta-lactamase (ESBL)-producing bacteria were isolated. CONCLUSION The spectrum of bacteria has only slightly changed over the years from 2001 to 2012, whereby an increase was only found in the number of CNS infections. Multi-drug resistant bacteria, in particular MRSE have increased. The changes in MRSE found in this study do not appear to warrant a general rethinking of antibiotic prophylaxis.

Infektionen von Hüft- und Knieendoprothesen

BACKGROUND Because of the rise in primary implantations in elective knee and hip arthroplasty, the number of complications, particularly due to prosthetic infections has increased. Partly due to multimorbidities, an increase in geriatric patients and often unnecessary use of antibiotics, a change in the spectrum of bacteria with an increase in multi-drug resistant pathogens is to be expected. For physicians this creates not only new medical and economic but also sociopolitical challenges. QUESTION Has the spectrum of bacteria in prosthetic joint infections after total hip arthroplasty (THA) and total knee arthroplasty (TKA) changed during the 12-year period 2001-2012 in our hospital and what role do multi-drug resistant bacteria play? INVESTIGATION COLLECTIVE A total of 320 patients with prosthetic joint infections (PJI) following TKA or THA could be identified and were included in this study. The sample consisted of 172 patients with an infection after THA (56 % females n = 96 and 44 % males n = 76) with a mean age of 70.9 years (range 39-92 years) and 148 patients with an infection after TKA (55 % females n = 82 and 45 % males n = 66) with a mean age of 70.7 years (range 15-87 years). The bacteria detected and the development over the course of time were evaluated. RESULTS An increase was found in the occurrence of coagulase negative staphylococci (CNS), in particular Staphylococcus epidermidis (2001-2003 n = 10 and 2010-2012 n = 27). The proportion of oxacillin and methicillin-resistant Staphylococcus epidermidis (MRSE) was also found to increase (0 % in 2001-2003 and 74 % in 2010-2012). A substantial increase in methicillin-resistant Staphylococcus aureus (MRSA) infections could not be found and there was a tendency towards reduction in the total number of Staphylococcus aureus infections. A total of five extended spectrum beta-lactamase (ESBL)-producing bacteria were isolated. CONCLUSION The spectrum of bacteria has only slightly changed over the years from 2001 to 2012, whereby an increase was only found in the number of CNS infections. Multi-drug resistant bacteria, in particular MRSE have increased. The changes in MRSE found in this study do not appear to warrant a general rethinking of antibiotic prophylaxis.