Efficacy of lysostaphin-coated titanium plates on implant-associated MRSA osteitis in minipigs

PURPOSE

The growing incidence of implant-associated infections (IAIs) caused by biofilm-forming Staphylococcus aureus in combination with an increasing resistance to antibiotics requires new therapeutic strategies. Lysostaphin has been shown to eliminate this biofilm. Own studies confirm the effectiveness in a murine model. The current study characterizes the effects of lysostaphin-coated plates in an IAI minipig model.

METHODS

The femur of 30 minipigs was stabilized with a five-hole plate, a bone defect was created, and in 20 cases methicillin-resistant Staphylococcus aureus was applied. Ten animals served as control group. After 14 days, local debridement, lavage, and plate exchange (seven-hole plate) were performed. Ten of the infected minipigs received an uncoated plate and 10 a lysostaphin-coated plate. On day 84, the minipigs were again lavaged, followed by euthanasia. Bacterial load was quantified by colony-forming units (CFU). Immunological response was determined by neutrophils, as well as interleukins. Fracture healing was assessed radiologically.

RESULTS

CFU showed significant difference between infected minipigs with an uncoated plate and minipigs with a lysostaphin-coated plate (p = 0.0411). The infection-related excessive callus formation and calcification was significantly greater in the infected animals with an uncoated plate than in animals with a lysostaphin-coated plate (p = 0.0164/p = 0.0033). The analysis of polymorphonuclear neutrophils and interleukins did not reveal any pioneering findings.

CONCLUSION

This study confirms the minipig model for examining IAI. Furthermore, coating of plates using lysostaphin could be a promising tool in the therapeutic strategies of IAI. Future studies should focus on coating technology of implants and on translation into a clinical model.

The influence of fracture severity on postoperative outcome and quality of life after locking plate fixation of proximal humeral fractures

Objective:

For proximal humeral fractures open reduction und internal fixation (ORIF) with a fixed-angle plate is considered the gold standard for surgical management. However, it can lead to poor functional outcomes and is associated with postoperative complications. Therefore, the purpose of this study was to investigate the influence of fracture severity by applying a new classification (simple versus complex) on clinical outcome and quality of life after ORIF of proximal humerus fractures.

Methods:

We conducted a prospective clinical study with an average follow-up period of 12 (SD 1) months after ORIF of proximal humeral fractures with a fixed-angle plate. The postoperative function and quality of life was measured using the Oxford Shoulder Score (OSS) and the Constant Score. Data was tested for statistical significance with the Mann-Whitney test and Fisher's exact test. Based on the findings of this study a simplified fracture classification system has been developed.

Results:

Seventy-two patients with a mean age of 65 years (SD 12) with 69% being males were included. According to the Neer classification, 35% (n=25) non-displaced (“one-part fractures”), 19% (n=14) two-part fractures, 15% (n=11) three-part fractures and 31% (n=22) four-part fractures were detected. Regarding the AO/OTA classification, 18% (n=13) were type A fractures, 43% (n=31) type B and 39% (n=28) type C fractures. From these criteria we derived our own fracture classification, including 50% (n=36) simple and 50% (n=36) severe fractures. Patients with simple fracture types achieved significantly higher total values in the Constant Score as well as the OSS (p=0.008; p=0.013). The cumulative incidence of complications in the entire patient collective was 14% (n=10) with humeral head necrosis (n=5) occurring only in the severe fracture group.

Conclusions:

The postoperative clinical outcome as well as the incidence of humeral head necrosis after ORIF of proximal humeral fractures with a fixed-angle plate correlates with the fracture type and severity. The newly derived fracture classification into simple and severe fractures is suitable with regard to clinical results and complication rate. However, prospective studies comparing ORIF vs. conservative treatment of proximal humeral fractures of the same severity are required.

Level of Evidence:

III

[Differences in injury patterns in motorcycle accidents involving children and adolescents]

Hintergrund

Verkehrsunfälle und ihre Verletzungsfolgen stellen eine häufige traumatische Ursache für das Versterben und für das Auftreten von irreversiblen Schäden bei Kindern und Jugendlichen dar. Bei Motorradunfällen unterscheiden sich dabei Verletzungsmuster abhängig vom Patientenalter.

Ziel der Arbeit

Ziel dieser Studie ist es, die typischen Verletzungsmuster nach Motorradunfällen im Kindes- und Jugendalter vergleichend zu beschreiben, da diese einen ausschlaggebenden Einfluss auf die Prävention sowie die adäquate Behandlung der jeweiligen Patientengruppen bieten können.

Material und Methoden

In die Studie wurden innerhalb der Jahre 2002–2018 22.923 Patienten aus dem TraumaRegister der Deutschen Gesellschaft für Unfallchirurgie (DGU®) eingeschlossen. Die Auswertung erfolgte in 4 Altersgruppen: Gruppe 1 (4 bis 15 Jahre), Gruppe 2 (16 bis 17 Jahre), Gruppe 3 (18 bis 20 Jahre) sowie Gruppe 4 (21 bis 50 Jahre) als Kontrolle.

Ergebnisse

In Gruppe 2 stellten Extremitätenverletzungen das häufigste Verletzungsmuster dar und traten überwiegend im Bereich der unteren Extremität auf. Zudem ergab die Analyse, dass Gruppe 1 häufiger ein schweres Schädel-Hirn-Trauma erleidet, trotz initial schlechtem Zustand aber ein besseres Outcome aufweist. Thorakale, abdominelle sowie Wirbelsäulen- und Beckenverletzungen kommen bei den jüngeren Altersgruppen seltener vor. Insbesondere stellen Rippenfrakturen eine Rarität bei Kindern dar. In der Diagnostik werden Kinder im Vergleich zu Erwachsenen seltener einer Ganzkörper-CT-Diagnostik zugeführt.

Diskussion

Die Studie deckt altersabhängige Unterschiede in den Verletzungsmustern von Patienten auf, die als Beifahrer oder Fahrer eines Motorrades in einen Unfall involviert waren. Zudem konnten ebenso Unterschiede in der prä- und innerklinischen Versorgung herausgearbeitet werden.

Possible risk factors for acute and chronic deep periprosthetic joint infections in primary total knee arthroplasty. Do BMI, smoking, urinary tract infections, gender, and ASA classification have an impact?

Purpose

Aim of this retrospective study was to evaluate the impact of the patient related factors body mass index (BMI), urinary tract infection, current smoking, gender, and American Society of Anesthesiologists (ASA) classification on the incidence of acute and chronic deep periprosthetic joint infections (PJI) in total knee arthroplasty (TKA).

Methods

All patients undergoing revision surgery for a deep PJI of primary TKA between July 2012 and December 2016 were included in this study. All relevant data was collected from the medical records. Acute deep PJI was defined when PJI was diagnosed within the first 6 weeks after primary TKA, chronic PJI was defined when patients demonstrated PJI later than 6 weeks after primary TKA.

Results

A total of 57 patients was included in this study with 13 cases of acute PJI and 44 of chronic PJI. Overweight patients (BMI > 25 kg/m²) represent a significantly larger proportion in both PJI groups (p < 0.05). Current smokers had an significantly increased risk for acute and chronic PJI (p < 0.05). In the acute PJI group 46.2% patients had an postoperative urinary tract infection.

Conclusion

An elevated BMI (>25 kg/m²), current smoking and urinary tract infection are possible risk factors for acute and chronic deep PJI. After primary TKA screening for urinary tract infection is recommendable to prevent predominantly acute deep PJI.

Is computerised 3D templating more accurate than 2D templating to predict size of components in primary total hip arthroplasty?

INTRODUCTION

The aim of this study was to compare the accuracy of preoperative templating in total hip arthroplasty (THA) using conventional 2-dimensional (2D) and computed tomography (CT)-based 3-dimensional (3D) measures.

METHODS

One hundred and sixteen consecutive primary THAs were analysed. The preoperative diagnosis was primary osteoarthritis in all cases. The 2D templating and the 3D templating were performed by two different residents. All templating results were available for the orthopaedic surgeon performing the procedure. Accuracies with regard to the predicted and actual implant sizes were determined for each procedure. Implantation of the size as planned was defined as "exact", whereas the use of components within one size larger or smaller (±1) as planned were defined as "accurate."

RESULTS

The 3D templating was significantly more accurate in predicting implant sizing compared to 2D templating for primary total hip arthroplasty (THA). The difference was statistically significant for the cup templating (''exact'' p = 0.02; ''accurate'' p = 0.01) and for the stem templating (''exact'' p = 0.04; ''accurate'' p = 0.01).

CONCLUSION

Our results support the superiority of 3D templating over 2D templating in predicting implant size.

Normal CRP and WBC values in total hip arthroplasty (THA) with signs of loosening. Do we need a joint aspiration?

PURPOSE

Overall Total hip arthroplasty (THA) is a very successful procedure. However, in case of complication dedicated management is required. Two major complications of THA failures are aseptic loosening (AL) and periprosthetic joint infection (PJI). The primary hypothesis of this study was that joint aspirations in patients with signs of loosening after THA are capable to detect PJI in suspected AL with negative serologic testing.

METHODS

In this study a total of 108 symptomatic patients with radiographic signs of prosthetic loosening and hip pain in THA were included. Based on a standardized algorithm all patients underwent serological testing followed by joint aspiration preoperatively. Intraoperatively harvested samples were subjected to microbiological testing and served as the gold standard in differential diagnosis. Demographics, as well as the results of serologic and microbiological testing were collected from the medical records.

RESULTS

Of the included patients 85 were finally diagnosed with an AL and 23 with PJI. Within the patients with PJI 13 (56%) patients demonstrated elevated CRP and WBC counts, as well as positive synovial cultures after joint aspiration. In ten patients (44%) diagnosed with PJI neither CRP nor WBC were abnormal.

CONCLUSION

The diagnosis of PJI can be difficult in THA with radiographic signs of loosening. Clinical features including pain, fever, and local sings of infection are uncommon especially a long period after index operation. First-line screening testing relies on serological evaluation of CRP and WBC. However, normal CRP and WBC values cannot rule out a PJI. These cases can be detected by joint aspiration and synovial cultures reliably.

Fractures in German elite male soccer players

BACKGROUND

Aim of this retrospective cohort study was to identify fracture epidemiology and off times after different types of fractures in German male elite soccer players from the first division Bundesliga based on information from the public media.

METHODS

Exposure and fracture data over 7.5 consecutive seasons (2009/10 until the first half of 2016/17) were collected from two media-based register (transfermarkt.de® and kicker.de®).

RESULTS

Overall, 357 fractures from 290 different players were recorded with an incidence of 0.19/1000 hours of exposure (95% CI: 0.14-0.24). Most fractures in German elite soccer players involved the lower extremities (35.3%), the head/face (30.3%) and the upper extremities (24.9%). The median off time after a fracture in German elite male professional soccer in 7.5 Season was 51.1 days (range 0-144). The number of fractures per 100 players per season decreased between 2009 and 2016. There was no significant difference in overall fracture incidence when comparing players at different position (P=0.11). Goalkeepers have a significantly (P<0.02) higher likelihood of suffering hand and finger fractures and they are significantly (P<0.03) less prone of suffering foot fractures, cranial and maxillofacial fractures (P<0.04). compared to outfield players.

CONCLUSIONS

This study can confirm that male professional soccer teams experience 1-2 fractures per season in German elite soccer. The incidence of fractures in elite German soccer players decreased between 2009 and 2016. The most fractures occur in the lower extremities and there is no difference in overall fracture risk for players at different playing positions. The information from our study might be of a great importance to medical practitioners, soccer coaches and soccer manager.

Hyperbaric oxygen therapy improves angiogenesis and bone formation in critical sized diaphyseal defects

Besides the use of autologous bone grafting several osteoconductive and osteoinductive methods have been reported to improve bone healing. However, persistent non-union occurs in a considerable number of cases and compromised angiogenesis is suspected to impede bone regeneration. Hyperbaric oxygen therapy (HBO) improves angiogenesis. This study evaluates the effects of HBO on bone defects treated with autologous bone grafting in a bone defect model in rabbits. Twenty-four New-Zealand White Rabbits were subjected to a unilateral critical sized diaphyseal radius bone defect and treated with autologous cancellous bone transplantation. The study groups were exposed to an additional HBO treatment regimen. Bone regeneration was evaluated radiologically and histologically at 3 and 6 weeks, angiogenesis was assessed by immunohistochemistry at three and six weeks. The additional administration of HBO resulted in a significantly increased new bone formation and angiogenesis compared to the sole treatment with autologous bone grafting. These results were apparent after three and six weeks of treatment. The addition of HBO therapy to autologous bone grafts leads to significantly improved bone regeneration. The increase in angiogenesis observed could play a crucial role for the results observed.

The effect of bone marrow concentrate and hyperbaric oxygen therapy on bone repair

Neoangiogenesis represents an essential part of bone regeneration. Therefore the improvement of neovascularization is the subject of various research approaches. In addition autologous mesenchymal stem cells concentrate in combination with bone substitute materials have been shown to support bone regeneration. In a rabbit model we examined the proposed synergistic effect of hyperbaric oxygen therapy (HBOT) and bone marrow concentrate (BMC) with porous calcium phosphate granules (CPG) on neoangiogenesis and osseous consolidation of a critical- size defect. The animal groups treated with HBOT showed a significantly higher microvessel density (MVD) by immunhistochemistry. Furthermore HBOT groups presented a significantly larger amount of new bone formation histomorphometrically as well as radiologically. We conclude that the increase in perfusion as a result of increased angiogenesis may play a key role in the effects of HBOT and consequently promotes bone healing.

Fracture-dislocations of the carpometacarpal joints of the ring and little finger

We report the functional and radiographic results of 16 patients with fracture-dislocations of the ring and little finger carpometacarpal joints and 23 cases with fracture-dislocations of only the little finger carpometacarpal joint treated between 2006 and 2012. The above two cohort populations of patients were treated with either open reduction and pin fixation or closed reduction and pin fixation. These patients were followed for a mean of 13 months (range 9 to 48). The DASH scores for patients with fracture-dislocations of the ring and little finger carpometacarpal joints were 6.0 and of the little finger carpometacarpal joint 7.2. We found no functional differences in term of DASH scores after treatment between patients with fracture-dislocations of only the little finger carpometacarpal joint and both the ring and little finger carpometacarpal joints.

The treatment of the acute Essex-Lopresti injury

The Essex-Lopresti injury (ELI) of the forearm is a rare and serious condition which is often overlooked, leading to a poor outcome. The purpose of this retrospective case study was to establish whether early surgery can give good medium-term results. From a group of 295 patients with a fracture of the radial head, 12 patients were diagnosed with ELI on MRI which confirmed injury to the interosseous membrane (IOM) and ligament (IOL). They were treated by reduction and temporary Kirschner (K)-wire stabilisation of the distal radioulnar joint (DRUJ). In addition, eight patients had a radial head replacement, and two a radial head reconstruction. All patients were examined clinically and radiologically 59 months (25 to 90) after surgery when the mean Mayo Modified Wrist Score (MMWS) was 88.4 (78 to 94), the mean Mayo Elbow Performance Scores (MEPS) 86.7 (77 to 95) and the mean disabilities of arm, shoulder and hand (DASH) score 20.5 (16 to 31): all of these indicate a good outcome. In case of a high index of suspicion for ELI in patients with a radial head fracture, we recommend the following: confirmation of IOM and IOL injury with an early MRI scan; early surgery with reduction and temporary K-wire stabilisation of the DRUJ; preservation of the radial head if at all possible or replacement if not, and functional bracing in supination. This will increase the prospect of a good result, and avoid the complications of a missed diagnosis and the difficulties of late treatment.

The early phase influence of bone marrow concentrate on metaphyseal bone healing

Bone marrow concentrate (BMC) contains high densities of progenitor cells. Therefore, in critical size defects BMC may have the potency to support bone healing. The aim of this study was to investigate the effect of BMC in combination with calcium phosphate granules (CPG) on bone defect healing in a metaphyseal long bone defect in mini-pigs. A metaphyseal critical-size bone defect at the proximal tibia of 24 mini-pigs was filled with CPG combined with BMC, CPG solely (control group) or with an autograft. Radiological and histomorphometrical evaluations after 6 weeks (42 days) showed significantly more bone formation in the BMC group in the central area of the defect zone and the cortical defect zone compared to the CPG group. At the same time the resorption rate of CPG increased significantly in the BMC group. Nevertheless, compared to the BMC group the autograft group showed a significantly higher new bone formation radiologically and histomorphometrically. In BMC the count of mononuclear cells was significantly higher compared to the bone marrow aspirate (3.5-fold). The mesenchymal progenitor cell characteristics of the cells in BMC were confirmed by flow cytometry. Cells from BMC created significantly larger colonies of alkaline phosphatase-positive colony forming units (CFU-ALP) (4.4-fold) compared to cells from bone marrow aspirate. Nevertheless, even in the BMC group complete osseous bridging was only detectable in isolated instances of the bone defects. Within the limitations of this study the BMC+CPG composite promotes bone regeneration in the early phase of bone healing significantly better than the isolated application of CPG. However, the addition of BMC does not lead to a solid fusion of the defect in the early phase of bone healing an still does not represent an equal alternative to autologous bone.

The progress of early phase bone healing using porous granules produced from calcium phosphate cement

Objective

Bone grafting is a vital component in many surgical procedures to facilitate the repair of bone defects or fusions. Autologous bone has been the gold standard to date in spite of associated donor-site morbidity and the limited amount of available donor bone. The aim of this study was to investigate the progress of bone regeneration and material degradation of calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder compared to the use of autologous bone grafting in the treatment of "critical size defects" on load-bearing long bones of minipigs.

Methods

A critical size defect in the tibial metaphysis of 16 mini-pigs was filled either with autologous cancellous graft or with micro- and macroporous carbonated, apatic calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder. After 6 weeks, the specimens were assessed by X-ray and histological evaluation. The amount of new bone formation was analysed histomorphometrically.

Results

The semi-quantitative analysis of the radiological results showed a complete osseous bridging of the defect in three cases for the autograft group. In the same group five animals showed a beginning, but still incomplete bridging of the defect, whereas in the CPG group just two animals developed this. All other animals of the CPG group showed only a still discontinuous new bone formation. Altogether, radiologically a better osseous bridging was observed in the autograft group compared to the CPG group.

Histomorphometrical analysis after six weeks of healing revealed that the area of new bone was significantly greater in the autograft group concerning the central area of the defect zone (p < 0.001) as well as the cortical defect zone (p < 0.002). All defects showed new bone formation, but only in the autograft group defects regenerated entirely

Conclusions

Within the limits of the present study it could be demonstrated that autologous cancellous grafts lead to a significantly better bone regeneration compared to the application of calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder after 6 weeks. In the early phase of bone-healing, the sole application of CPG appears to be inferior to the autologous cancellous grafts in an in vivo critical size defect on load-bearing long bones of mini-pigs.

[Radial nerve palsy associated with humeral shaft fractures - early exploration or expectant procedure? An analysis concerning current strategies of treatment]

BACKGROUND

With a prevalence from 11.8 to 18% no fracture is as often associated with nerve damage as the humeral shaft fracture. Whether the radial nerve should be surgically explored in association with a palsy in humeral shaft fractures in order to exclude an interposition or discontinuity is being discussed controversially. The aim of this study was to assess the strategies for primary care of radial nerve palsies associated with humeral shaft fractures in Germany.

MATERIAL AND METHODS

In a standardised survey 495 traumatological and 134 neurosurgical clinics were interviewed regarding the treatment of primary radial nerve palsies after humeral shaft fractures. The distribution of the survey included all level-one trauma centres. Statistics were based on the supply strategies, the number of observed contusions, discontinuities and inter-position of the N. radialis in the fracture gap. Moreover, the results were recorded after primary neurorrhaphy.

RESULTS

The evaluable response rate to the questionnaire was 56% (university hospitals 77%, level-one trauma centres 63%, level-two trauma centres 70%, level-three trauma centres 44%). 6097 humeral shaft fractures have been treated per year, the incidence of primary radial nerve palsy was 8.6%. Regarding the management strategies, 59% of the hospitals advocated exploration of the nerve, while 25% reported that the decision depends on the individual case. 16% reject the exploration in case of a primary nerve palsy. In the case of an exploration, contusions (74%) of the nerve were largely seen, followed by nerve interpositions in the fracture gap (19%) and discontinuity (7%). In the case of neurorrhaphy, a partial or complete remission was found in 87% of cases.

DISCUSSION

Although a primary expectant procedure is recommended in the literature due to the high spontaneous remission rate of 90%, an early exploration of the nerve is often preferred in clinical practice. In these cases, the use of an interlocking intramedullary nail as a minimally invasive treatment option does not appear useful due to the direct exposure of the fracture zone and the radial nerve. Interestingly, the feared discontinuity occurs rarely. The impact of nerve interposition in the fracture gap without surgical exploration remains unclear due to the lack of visibility.

CONCLUSION

There is no consensus concerning the treatment of radial nerve palsies after humeral shaft fractures in Germany. Discontinuities are rare, the rate of spontaneous recoveries is high. Whether and when an exploration of the radial nerve is obligatory in primary radial palsy remains unclear and should be clarified by prospective randomised trials.