Jan Schmolders

Polymicrobial infections reduce the cure rate in prosthetic joint infections: outcome analysis with two-stage exchange and follow-up ≥two years

PurposeProsthetic joint infections (PJI) are a serious and challenging complication after total joint arthroplasty. According to the literature, most PJI are monomicrobial infections caused by gram-positive cocci. The number of polymicrobial PJI might be underrepresented in the literature and only limited data are available regarding the outcome of polymicrobial PJI. Our hypothesis was that polymicrobial PJI are associated with a reduced cure rate compared with monomicrobial PJI.MethodsRoutine clinical data were collected and analysed retrospectively as anonymised, aggregated data. A total of 77 consecutive patients with 77 confirmed PJI and proven infectious organism of the hip and knee joint treated within a two-stage exchange concept and a follow-up ≥xa0twoxa0years were investigated. Detection of the infectious organism was based on multiple microbiological cultures taken intra-operatively. Superficial wound swabs or swabs from sinus tracts were not taken into account. Data were grouped into polymicrobial and monomicrobial PJI. The main outcome variable was “definitively free of infection after twoxa0years” as published. Second, we considered several variables as potential confounders or as risk factors.ResultsA total of 42 men and 35 women with 46 infected total hip arthroplasties and 31 infected total knee arthroplasties were evaluated. In 37 (46.6xa0%) of our 77 patients a polymicrobial PJI could be detected. We found a significant association between polymicrobial PJI and the outcome parameter definitively free of infection after twoxa0years with an odds ratio (OR) of 0.3 [95xa0% confidence interval (CI) 0.1–1.0]. The rate of patients graded as definitively free of infection after twoxa0years was 67.6xa0% for polymicrobial infections vs. 87.5xa0% for monomicrobial infections. The American Society of Anesthesiologists (ASA) score (OR 0.4, 95xa0% CI 0.2–1.0, pu2009=u20090.062) was identified as a borderline significant covariable.ConclusionsOur data suggest that polymicrobial PJI might be underrepresented in the current literature. Additionally, the presence of multiple infectious organisms is associated with a reduced rate after twoxa0years with 67.6 vs 87.5xa0% for monomicrobial infections. Special attention and extra care should be considered for these patients.

Management of severe periacetabular bone loss combined with pelvic discontinuity in revision hip arthroplasty

PurposeRevision of failed total hip arthroplasty with massive acetabular bone loss resulting in pelvic discontinuity represents a rare but challenging problem. The objective of this study was to present short to mid-term results of revision total hip arthroplasty with a custom-made acetabular implant in a consecutive series of patients with pelvic discontinuity.MethodsWe retrospectively reviewed 18 consecutive patients with massive acetabular bone loss (Paprosky Type 3B) resulting in pelvic discontinuity reconstructed with revision total hip arthroplasty using a custom-made acetabular component. The prosthesis was created on the basis of a thin-cut 1-mm computed tomography (CT) scan of the pelvis. Initial stability of the implant was obtained by screw fixation. Harris hip score and sequential radiographs were used to evaluate the clinical and radiographic results.ResultsAt an average follow up of 30xa0months (range 17–62xa0months) 16 of 18 (88.9xa0%) custom-made implants were considered radiographically stable without signs of acetabular migration of more than 2xa0mm in the horizontal or vertical direction, implant rotation or screw breakage. Complications included two periprosthetic joint infections treated with explantation of the implant. Three patients had recurrent dislocations postoperatively. The mean Harris hip score improved from 28u2009±u200912 points preoperatively to 69u2009±u200913 points at the time of last follow up.ConclusionTreatment of acetabular bone loss and pelvic discontinuity with a custom-made acetabular component can provide a durable solution with good clinical and radiographic results.

RANK-ligand and osteoprotegerin as biomarkers in the differentiation between periprosthetic joint infection and aseptic prosthesis loosening

AIM To assess serum levels of RANK-ligand (RANKL) and osteoprotegerin (OPG) as biomarkers for periprosthetic joint infection (PJI) and compare their accuracy with standard tests. METHODS One hundred and twenty patients presenting with a painful total knee or hip arthroplasty with indication for surgical revision were included in this prospective clinical trial. Based on standard diagnostics (joint aspirate, microbiological, and histological samples) and Musculoskeletal Infection Society consensus classification, patients were categorized into PJI, aseptic loosening, and control groups. Implant loosening was assessed radiographically and intraoperatively. Preoperative serum samples were collected and analyzed for RANKL, OPG, calcium, phosphate, alkaline phosphatase (AP), and the bone-specific subform of AP (bAP). Statistical analysis was carried out, testing for significant differences between the three groups and between stable and loose implants. RESULTS All three groups were identical in regards to age, gender, and joint distribution. No statistically significant differences in the serum concentration of RANKL (P = 0.16) and OPG (P = 0.45) were found between aseptic loosening and PJI, with a trend towards lower RANKL concentrations and higher OPG concentrations in the PJI group. The RANKL/OPG ratio was significant for the comparison between PJI and non-PJI (P = 0.005). A ratio > 60 ruled out PJI in all cases (specificity: 100%, 95%CI: 89, 11% to 100.0%) but only 30% of non-PJI patients crossed this threshold. The positive predictive value remained poor at any cut-off. In the differentiation between stable and loose implants, none of the parameters measured (calcium, phosphate, AP, and bAP) showed a significant difference, and only AP and bAP measurements showed a tendency towards higher values in the loosened group (with P = 0.09 for AP and P = 0.19 for bAP). CONCLUSION Lower RANKL and higher OPG concentrations could be detected in PJI, without statistical significance.

Two-stage knee arthrodesis with a modular intramedullary nail due to septic failure of revision total knee arthroplasty with extensor mechanism deficiency

BACKGROUNDnPeriprosthetic joint infection is a serious complication and reconstruction after failed revision total knee arthroplasty with significant bone loss and compromised soft-tissues can be challenging. Objective of this study was to assess clinical and functional results, implant survival and infection recurrence rates in patients treated with two-stage arthrodesis after failed revision TKA with extensor mechanism deficiencies due to PJI, and to identify the factors that affect outcomes after surgery.nnnMETHODSnThirty seven patients with PJI treated within a two-stage exchange and reimplantation of an arthrodesis nail between 2008 and 2014 were included. Systemic and local risk factors were graded preoperatively according to McPherson et al. All patients were treated according to a structured treatment algorithm. Clinical and functional evaluation was performed using the Oxford Knee Score and the Visual Analogue Scale.nnnRESULTSnThirty two of 37 patients (86.5%) were graded as free of infection. Five patients (13.5%) had recurrent infection after arthrodesis with the need of revision surgery. Mean leg-length discrepancy was 2.2cm. The mean VAS for pain was three, the mean Oxford Knee Score was 38±9. Total implant survival at a 74month follow-up was 74.3% (95% CI: 45.4 to 91.1%), as determined by Kaplan-Meier survival curves. Local McPherson Score, as well as number of revisions was found to be of significant influence to the survival rate.nnnCONCLUSIONSnSeptic failure of revision knee arthroplasty can be effectively treated with two-stage arthrodesis using a modular intramedullary nail, providing a stable and painless limb with satisfactory functional results and acceptable infection eradication rates.

Single Molecule Microscopy Reveals an Increased Hyaluronan Diffusion Rate in Synovial Fluid from Knees Affected by Osteoarthritis.

Osteoarthritis is a common and progressive joint disorder. Despite its widespread, in clinical practice only late phases of osteoarthritis that are characterized by severe joint damage are routinely detected. Since osteoarthritis cannot be cured but relatively well managed, an early diagnosis and thereby early onset of disease management would lower the burden of osteoarthritis. Here we evaluated if biophysical parameters of small synovial fluid samples extracted by single molecule microscopy can be linked to joint damage. In healthy synovial fluid (ICRS-scoreu2009<u20091) hyaluronan showed a slower diffusion (2.2u2009μm2/s, Nu2009=u20095) than in samples from patients with joint damage (ICRS-scoreu2009>u20092) (4.5u2009μm2/s, Nu2009=u200916). More strikingly, the diffusion coefficient of hyaluronan in healthy synovial fluid was on average 30% slower than expected by sample viscosity. This effect was diminished or missing in samples from patients with joint damage. Since single molecule microscopy needs only microliters of synovial fluid to extract the viscosity and the specific diffusion coefficient of hyaluronan this method could be of use as diagnostic tool for osteoarthritis.

Falling and fall risk in adult patients with severe haemophilia

The objective of this study was to define fall rates and to identify possible fall risk factors in adult patients with severe haemophilia.nnnPATIENTS, MATERIAL, METHODSn147 patients with severe haemophilia A and B were evaluated using a standardized test battery consisting of demographic, medical and clinical variables and fall evaluation.nnnRESULTSn41 (27.9u2009%) patients reported a fall in the past 12 months, 22 (53.7u2009%) of them more than once. Young age, subjective gait insecurity and a higher number of artificial joints seem to be risk factors for falling.nnnCONCLUSIONnFalls seem to be a common phenomenon in patients with severe haemophilia. Fall risk screening and fall prevention should be implemented into daily practice.

Multiples Myelom – aktuelle Standards der operativen Therapie

BACKGROUNDnMultiple myeloma is a haematological blood cancer in elderly patients, in which neoplastic cell populations cause osteolytic destruction in the bone skeleton. More than 50% of all patients sustain pathological fractures during the course of their disease. Of all malignant lesions of the spine, multiple myeloma is the most frequent spinal tumour and accounts for approximately 15% of all cases. 8u200a-u200a10% of the patients develop neurological deficits. In addition to systemic antineoplastic therapy, surgical treatment is often required in order to reconstruct and stabilise bone defects associated with multiple myeloma, as well as to address tumour-related complications.nnnMETHODSnA comprehensive literature search was performed in PubMed using the keywords multiple myeloma and surgery or fracture. This served to evaluate the available primary and secondary literature on the current status of the surgical therapy of multiple myeloma. Systematic reviews, meta-analyses and clinical studies and international recommendations for therapy were included - from 1975 until the spring of 2018.nnnDISCUSSIONnStabilising surgery is essential in order to retain and restore function and mobility in bone sections affected by myeloma and for tumour-related osseous defects due to pathological fracture or instability. Absolute and relative indications for surgical treatment are distinguished and are based on the extent and localisation of bone lesions, manifest fractures, accompanying side effects and complications such as neurological deficits and bone pain that is intractable to conservative treatment. The range of options in surgical treatment of myeloma-related bone damage within the upper and lower extremities ranges from hybrid stabilisation procedures combining bone cement and various implants, to conventional and modular tumour prostheses systems. In spinal surgery, minimally invasive procedures such as kyphoplasty or vertebroplasty, as well as selective decompressive operations, dorsal spinal fusion and vertebral replacement are performed in cases of osseous defects and related fractures or instabilities. The surgical treatment and time of operation is determined by the general individual risk profile and prognosis of the patient with multiple myeloma. The surgical approach should have the objective of a final and load stable solution for the patient, which takes into account the frequent long-term course of the disease. Radiotherapy is often recommended after surgery.nnnCONCLUSIONnIn therapy of multiple myeloma, surgical treatment is often required in order to reduce distress and retain the function and flexibility of myeloma affected bone sections and the mobility and quality of life of the cancer patient. The range of surgical strategies is complex and demanding.

Activity Pattern Analysis Indicates Increased but Balanced Systemic Coagulation Activity in Response to Surgical Trauma

In the nonbleeding patient, constant low-level activation of coagulation enables a quick procoagulant response upon an injury. Conversely, local activation of coagulation might influence the systemic activity level of coagulation. To characterize this interaction in more detail, activity pattern analysis was performed in patients undergoing elective surgeries. Blood samples were taken before, during, and 24 hours after surgery from 35 patients undergoing elective minor ( n u2009=u200918) and major ( n u2009=u200917) orthopaedic surgeries. Plasma levels of thrombin and activated protein C (APC) were measured using oligonucleotide-based enzyme capture assays, while those of prothrombin fragment 1.2, thrombin–antithrombin-complexes, and D-dimer were measured using commercially available enzyme-linked immunosorbent assays. In vitro thrombin generation kinetics were recorded using calibrated automated thrombography. Results showed that median plasma levels of up to 20 pM thrombin and of up to 12 pM APC were reached during surgery. D-dimer levels started to increase at the end of surgery and remained increased 24 hours after surgery, while all other parameters returned to baseline. Peak levels showed no significant differences between minor and major surgeries and were not influenced by the activity state at baseline. In vitro thrombin generation kinetics remained unchanged during surgery. In summary, simultaneous monitoring of the procoagulant and anticoagulant pathways of coagulation demonstrates that surgical trauma is associated with increased systemic activities of both pathways. Activity pattern analysis might be helpful to identify patients at an increased risk for thrombosis due to an imbalance between surgery-related thrombin formation and the subsequent anticoagulant response.

Knochenmetastasen – Pathophysiologie, Diagnostik und Therapie (Teil 1)

In Germany and other European countries, cancer is the second most common cause of death after cardiovascular disease. Although 5-year survival rates for several types of cancer have significantly improved over the last 30 years, metastasis to the bone almost always leads to incurable disease. Aside from the rare primary bone tumours, the treatment of bone metastases now accounts for a major part of tumour orthopaedic workload and requires close interdisciplinary coordination between specialists in oncology, radiology and the discipline of the primary tumour entity. Due to improvements in oncological treatment regimes, long survival times can be achieved. Therefore, the management of so-called SRE (skeletal-related events) has gained importance, even in palliative situations. On the basis of a selective literature review, the following article points out the underlying pathophysiological processes of bone metastases and outlines different diagnostic approaches and their relevance in the current clinical setting.