Inflammatory tissue response in human soft tissue is caused by a higher particle load near carbon fiber-reinforced PEEK compared to titanium plates.

Titanium as the leading implant material in locked plating is challenged by polymers such as carbon fiber-reinforced polyetheretherketone (CFR-PEEK), which became the focus of interest of researchers and manufacturers in recent years. However, data on human tissue response to these new implant materials are rare. Osteosynthesis plates and peri­implant soft tissue samples of 16 healed proximal humerus fractures were examined (n = 8 CFR-PEEK, n = 8 titanium). Soft tissue was analyzed by immunohistochemistry and µCT. The entrapped foreign bodies were further examined for their material composition by FTIR. To gain insight into their origin and formation mechanism, explanted and new plates were evaluated by SEM, EDX, profilometry and HR-CT. In the peri­implant soft tissue of the CFR-PEEK plates, an inflammatory tissue reaction was detected. Tissues contained foreign bodies, which could be identified as tantalum wires, carbon fiber fragments and PEEK particles. Titanium particles were also found in the peri­implant soft tissue of the titanium plates but showed a less intense surrounding tissue inflammation in immunohistochemistry. The surface of explanted CFR-PEEK plates was rougher and showed exposed and broken carbon fibers as well as protruding and deformed tantalum wires, especially in used screw holes, whereas scratches were identified on the titanium plate surfaces. Particles were present in the peri­implant soft tissue neighboring both implant materials and could be clearly assigned to the plate material. Particles from both plate materials caused detectable tissue inflammation, with more inflammatory cells found in soft tissue over CFR-PEEK plates than over titanium plates. STATEMENT OF SIGNIFICANCE: Osteosynthesis plates are ubiquitously used in various medical specialties for the reconstruction of bone fractures and defects and are therefore indispensable for trauma surgeons, ENT specialists and many others. The leading implant material are metals such as titanium, but recently implants made of polymers such as carbon fiber-reinforced polyetheretherketone (CFR-PEEK) have become increasingly popular. However, little is known about human tissue reaction and particle generation related to these new implant types. To clarify this question, 16 osteosynthesis plates (n = 8 titanium and n = 8 CFR-PEEK) and the overlying soft tissue were analyzed regarding particle occurrence and tissue inflammation. Tissue inflammation is clinically relevant for the development of scar tissue, which is discussed to cause movement restrictions and thus contributes significantly to patient outcome.

Open reduction and internal fixation of displaced head-split type humeral fractures and role of the rotator-interval approach.

Background: Open reduction and internal fixation (ORIF) of humeral head split fractures is challenging because of high instability and limited visibility. The aim of this retrospective study was to investigate the extend of the approach through the rotator interval (RI) on the reduction quality and functional outcome. Methods: 37 patients (mean age: 59 ± 16 years,16 female) treated by ORIF through a standard deltopectoral (DP) approach were evaluated. The follow-up period was at least two years. In 17 cases, the approach was extended through the RI. Evaluation was based on radiographs, Constant scores (CS) and DASH scores. Results: In group DP, "anatomic" reduction was achieved in 9 cases (45%), "acceptable" in 5 cases (25%), and "malreduced" in 6 cases (30%). In group RI, "anatomic" reduction was seen in 12 cases (71%), "acceptable" in 5 cases (29%), and "malreduced" in none (p = 0.04). In the DP group, the CS was 60.2 ± 16.2 and the %CS was 63.9 ± 22.3, while in the RI group, the CS was 74.5 ± 17.4 and the %CS was 79.1 ± 24.1 (p = 0.07, p = 0.08). DASH score was 22.8 ± 19.5 in DP compared to RI: 25.2 ± 20.6 (p = 0.53). Conclusions: The RI approach improves visualization as it enhances quality of fracture reduction, however functional outcomes may not differ significantly. Type of study and level of proof: Retrospective, level III.

Cartilage decisively shapes the glenoid concavity and contributes significantly to shoulder stability.

PURPOSE: Glenohumeral joint injuries frequently result in shoulder instability. However, the biomechanical effect of cartilage loss on shoulder stability remains unknown. The aim of the current study was to investigate biomechanically the effect of two severity stages of cartilage loss in different dislocation directions on shoulder stability. METHODS: Joint dislocation was provoked in 11 human cadaveric glenoids for 7 different directions between 3 o'clock (anterior) and 9 o'clock (posterior). Shoulder stability ratio (SSR) and concavity gradient were assessed in three states: intact, 3 mm and 6 mm simulated cartilage loss. The influence of cartilage loss on SSR and concavity gradient was statistically evaluated. RESULTS: Both SSR and concavity gradient decreased significantly between intact state and 6 mm cartilage loss in every dislocation direction (p ≤ 0.038), except concavity gradient in 4 o'clock direction. Thereby, anterior-inferior dislocation directions were associated with the highest decrease in both SSR and concavity gradient of up to 59.0% and 49.4%, respectively, being significantly bigger for SSR compared with all other dislocation directions (p ≤ 0.040). Correlations between concavity gradient and SSR for pooled dislocation directions were significant in each separate specimen's state (p < 0.001). CONCLUSION: From a biomechanical perspective, articular cartilage of the glenoid contributes significantly to the concavity gradient, correlating strongly with the associated loss in glenohumeral joint stability. The biggest effect of cartilage loss is observed in the most frequently occurring anterior-inferior dislocation directions, suggesting that surgical interventions to restore cartilage's surface and concavity should be considered for recurrent shoulder dislocations in presence of cartilage loss.

Functional outcomes before and after implant removal in patients with posttraumatic shoulder stiffness and healed proximal humerus fractures: does implant material (PEEK vs. titanium) have an impact? - a pilot study.

BACKGROUND: Posttraumatic shoulder stiffness remains a problem after proximal humerus fracture (PHF) despite good healing rates. The aim of this pilot study was to determine whether the implant material and overlying soft tissue have an effect on shoulder range of motion (ROM) before and after implant removal (IR). METHODS: 16 patients (mean age 55.2 ± 15.3 (SD) years; 62.5% female) were included who underwent operative treatment with locking plates of either carbon fiber reinforced Polyetheretherketone (PEEK) (PEEKPower® humeral fracture plate, Arthrex, Naples, Florida, USA, n = 8) or titanium alloy (Ti) (Philos®, DePuy Synthes, Johnson & Johnson Medical, Raynham, Massachusetts, USA, n = 8) for PHF. All patients presented with a limited ROM and persistent pain in everyday life after the fracture had healed, whereupon IR was indicated. ROM before and after IR were compared as well as the Constant Score (CS) and the CS compared to the contralateral shoulder (%CS) 1 year after IR. RESULTS: In group PEEK, elevation was 116.3° ± 19.2° pre- and 129.4° ± 23.7° post-IR (p = 0.027). External rotation was 35.0° ± 7.6° pre- and 50.6° ± 21.8° post-IR (p = 0.041). External rotation with the humerus abducted 90° was 38.8° ± 18.1° pre- and 52.5° ± 25.5° post-IR (p = 0.024). In group Ti, elevation was 110.0° ± 34.6° pre- and 133.8° ± 31.1° post-IR (p = 0.011). External rotation with the humerus at rest was 33.8° ± 23.1° pre- and 48.8° ± 18.7° post-IR (p = 0.048). External rotation with the humerus abducted 90° was 40.0° ± 31.6° pre- and 52.5° ± 22.5° post-IR (p = 0.011). Comparison of the two implant materials showed no significant difference. The overall CS was 90.3 ± 8.8, the %CS was 91.8% ± 14.7%. CONCLUSION: There was no significant difference in ROM, CS and %CS with respect to plate materials, although lower cell adhesion is reported for the hydrophobic PEEK. However, all patients showed improved functional outcomes after IR in this pilot study. In patients with shoulder stiffness following locked plating for PHF, implants should be removed and open arthrolysis should be performed, independently from the hardware material. LEVEL OF EVIDENCE: II.

Varus malposition relates to functional outcomes following open reduction and internal fixation for proximal humeral fractures: A retrospective comparative cohort study with minimum 2 years follow-up.

BACKGROUND: The aim of this study was to evaluate functional outcomes in patients with varus malposition following open reduction and internal fixation of displaced proximal humeral fractures. METHODS: Data of 685 patients with a mean age of 67±15.8 years (67% female), that were treated by open reduction and internal fixation for a displaced proximal humeral fracture at a level 1 trauma center, were analyzed. On standardized x-ray imaging, the degree of varus displacement was measured over a minimum of two years follow-up and patients were divided into three groups. Group A: anatomic or <10° of varus or valgus malposition, group B: 10-20° of varus malposition and group C: >20° varus malposition, while anatomic head-shaft-angle was defined 135° The groups were compared with regards to functional outcomes by means of the Constant Score (CS). RESULTS: In 565 patients with anatomic to minor <10° varus or valgus malposition (Group A), the mean CS was 72.5 ± 18.8 points. The %CS to the uninjured side was 87.2 ± 24.1 and the age and gender normalized nCS was 84.7 ± 21.7. In comparison, in group B (10-20° varus) the mean CS was 64.7 ± 16.9, the mean %CS was 84.5 ± 18.3 and the mean nCS was 76.2 ± 20.6. In group C (>20° varus) the mean CS was 54.1 ± 19.5, the mean was %CS: 72.3 ± 26.4 and the mean nCS was 64.8 ± 23.8 (p = 0.02, p = 0.03, p = 0.01). Overall, the CS, %CS and nCS correlated significantly with the degree of varus position (Pearson correlation, r = 0.23, r = 0.21, r = 0.25). CONCLUSION: Varus malposition is related to inferior functional outcomes compared to anatomic healing in patients treated by open reduction and internal fixation for proximal humeral fractures. The data supports suggestions to prevent varus malposition in open reduction and internal fixation. In severe >20° of varus malposition, revision surgery should be considered.

[Characterization of the seriously injured cyclist : An evaluation of the injury and treatment focus areas of 2817 patients]. / Charakterisierung des schwer verletzten Fahrradfahrers : Eine Auswertung der Hauptverletzungen und Behandlungsschwerpunkte von 2817 Patienten.

BACKGROUND: Transport statistics classify bicyclists in a separate road user collective. For medical reasons, this differentiation is applied as well. Much literature is published in this field. Nevertheless there is a lack of literature regarding the overall injury patterns in a defined injury severity collective. Most literature is about isolated injured regions in combination with a heterogeneous injury severity. Further parameters, such as injury patterns, epidemiological aspects, treatment focal points and characteristic outcomes, have also been studied. The aim of the present study was to evaluate and characterize injury patterns in a standardized and representative collective of severely injured bicyclists. Methods We analysed data from the Traumaregister DGU® from 2002 to 2010. In total, 2817 severely injured (ISS ≥ 9 and additional intensive/intermediate care unit) bicyclists were included. The primary endpoint was evaluation of injury patterns and injury focal points. In addition to that we analysed parameters like epidemiological aspects, circumstances of accident, treatment focal points and outcome. RESULTS: The mean age was 50.3 ± 20.9 years. Males accounted for 68.9 % (n = 1940). The mean ISS was 23.7 ± 12.6. The mean AIS regions were the head 71.9 % (n = 2025), the chest with 44.9 % (n = 1264) and the upper extremities 33.6 % (947). In 68.2 % of all cases an ISS ≥ 9 was achieved by a traumatic brain injury; 21.1 % of all cases were mono-injuries. A characteristic distribution of age and a characteristic prevalence of the accidents in relation to the weekday and the month could be shown. CONCLUSION: The present study analysed the largest ever published collective of severely injured bicyclists. Traumatic brain injury could clearly be shown as the main injury in this collective. Moreover, one of five cases achieved the state "severely injured" due to mono-injury.

Management of prehospital shoulder dislocation: feasibility and need of reduction.

PURPOSE: Dislocation of the shoulder is rare in the prehospital setting. The medical specialities of the emergency physicians are heterogeneous, and the level of experience is different. Aim of this study was to evaluate the feasibility, sufficiency, and need of prehospital reduction. METHODS: Over 12 months, 16 rescue stations in Germany and Austria documented cases. Points of examination were: incidence of reduction, influence of pathological findings, therapy and effectiveness of reduction. RESULTS: We included 70 patients. A reduction was undertaken in n = 47 (66.6 %). In n = 70 (100 %) perfusion was without pathological finding after reduction, all n = 7 (10 %) neurological pathologies declined after reduction. There was no significance in total implementation of prehospital reduction between surgeons and anaesthetists. N = 63 (90 %) of all patients received an immobilisation of the shoulder. N = 68 (97 %) of all patients were transported to a hospital. Time to arrival in hospital was in n = 50 (71.4 %) ≤10 min, in n = 17 (24.2 %) ≤20 min and in n = 3 (4.4 %) ≤30 min. CONCLUSION: Implementation of reduction is independent of pathological neurological or vascular findings. Knowledge and skill is enough to perform a reduction quiet effectively in all emergency physicians. No specific technique can be recommended for prehospital use, the importance of being skilled is more important than one method. Early reduction was performed most rapidly in surgeons, but as well in the recommended time by other medical disciplines. On documented timings to admission hospital waiver of reduction is doubt. Therefore, a reduction in the prehospital setting is possible, but not obligatory.

[Therapy of acute acromioclavicular joint instability. Meta-analysis of arthroscopic/minimally invasive versus open procedures]. / Therapie der akuten AC-Gelenk-Instabilität. Eine Metaanalyse arthroskopischer/minimal-invasiver vs. offener Verfahren.

BACKGROUND: A variety of surgical procedure are desrcibed for the treatment of acute acromioclavicular (AC-) joint injuries. Beside open techniques arthroscopic assisted procedures spread widely. Each surgical technique offers advantages and disadvantages, but none is currently accepted as a gold standard. Therefore, the study aims to review the evidence for arthroscopic and open surgical procedures in the treatment of acute AC joint instabilities. MATERIAL AND METHODS: According to the Cochrane Handbook for Systematic Reviews of Interventions we conducted a defined search of Medline and Embase database for articles publisher over the last ten years. RESULTS: The search resulted in 961 studies of which 32 were included in this review and 3 studies were suitable for a meta-analysis. The functional outcome (Constant score) showed a tendency towards better results after arthroscopic procedures (weighted mean difference 5.60, 95% confidence interval 0.36-10.64). There were no significant differences with respect to complication rates, secondary dislocation in the vertical plane, revision surgery and AC joint instability. CONCLUSION: There is insufficient evidence to inform the surgical management of acute AC joint instability. Due to inconsistent study designs there is no evidence for a general superiority of any of the open or arthroscopic procedures. Randomized, controlled studies are necessary to demonstrate whether arthroscopic techniques show a potential benefit in terms of a better functional outcome.

[Combined ac joint dislocation and distal clavicle fracture. Closed reduction and arthroscopically assisted coracoclavicular fixation]. / Kombinierte AC-Gelenk-Luxation und laterale Klavikulafraktur. Geschlossene Reposition und arthroskopisch gestützte korakoklavikuläre Fixierung.

BACKGROUND: A 55-year-old male patient sustained a dislocation of the acromioclavicular (AC) joint in combination with a distal clavicle fracture. METHODS: Following closed reduction of the fractured clavicle, arthroscopically assisted coracoclavicular fixation was performed. DISCUSSION AND CONCLUSION: A combined injury of a complete ac joint dislocation and a distal clavicle fracture is rare and is not included in currently available classification systems; therefore, in this article a classification and assessment of the stability of this injury as well as appropriate treatment options are discussed.

[Acute perioperative hemodilution without using hydroxyethyl starch : hemodynamic alterations under "controlled" hypovolemia]. / Akute perioperative Hämodilution ohne Verwendung von Hydroxyethylstärke : Hämodynamische Veränderungen unter "kontrollierter" Hypovolämie.

BACKGROUND: Up to now hydroxyethyl starch preparations have frequently been used to compensate for volume deficits accompanying blood withdrawal during acute normovolemic hemodilution. This approach was questioned with respect to the current limitations for use of hydroxyethyl starch solutions imposed by the European Medicines Agency. Because crystalloids distribute evenly across the whole extracellular compartment, 80 % of the infused solution will be "lost" to the interstitial space. Thus, a physiological adjustment of blood loss caused by hemodilution with crystalloids alone (1:5 ratio) seems hardly feasible and according to current data perhaps not even desirable. A 3:1 ratio (crystalloids versus blood loss) as applied in the current study can be regarded as a practical compromise between physiological needs and recommendations according to the literature (1.4:1) but will lead to moderate hypovolemia the hemodynamic consequences of which are not well described. AIM: The current study investigates the hemodynamic impact of a hemodilution with crystalloids under the precondition of a 3:1 substitution ratio compared to withdrawn blood. METHODS: In the context of acute perioperative hemodilution 10 otherwise healthy women graded I and II on the American Society of Anesthesiologists (ASA) classification scheduled for open gynecological cancer surgery underwent an average blood withdrawal of 1097 ± 285 ml which was substituted by an average of 3430 ± 806 ml of Ringer's lactate. The resulting deficit in blood volume was exactly quantified by a double tracer technique. Hemodynamic changes were evaluated by a combination of thermodilution and pulse contour analysis (PiCCO system®). Subsequently, the remaining volume deficit was compensated by 245 ± 64 ml of a 20 % albumin solution and hemodynamic parameters were again evaluated. RESULTS: When infusing Ringer's lactate in a 3:1 ratio compared to the actual blood loss, the blood volume decreased by 12 %. The volume effect of Ringer's lactate proved to be 17 %. While mean arterial pressure and heart rate remained constant, key hemodynamic parameters changed relevantly during the time course. A significant rise in cardiac output and myocardial contractility could be observed which was accompanied by a decrease in systemic vascular resistance. In contrast, cardiac preload and the parameters representing pulmonary vascular permeability remained unaltered. The infusion of 245 ± 64 ml of a 20 % albumin solution nearly completely restituted blood volume and led to an insignificant rise in systemic vascular resistance but did not normalize cardiac output or myocardial contractility. CONCLUSION: In the study population, the loss of intravascular fluid during perioperative haemodilution could be compensated by an increase in cardiac performance. However, whether patients with a reduced cardiac capacity (i.e. older patients) are capable to improve their cardiac output sufficiently in order to compensate hypovolemia accompanying perioperative haemodilution with crystalloids remains questionable.

Femoral marrow cavity bone harvesting used for arthroscopic refilling of misplaced or enlarged bone tunnels in revision ACL surgery: an arthroscopically supported technique with antegrade intramedullary bone harvesting by a reamer-irrigator-aspirator (RIA) system.

PURPOSE: In anterior cruciate ligament (ACL) revision surgery, refilling of misplaced or enlarged tunnels frequently requires bone harvesting from the iliac crest. Unfortunately, donor-site pain displays a relevant complication. In order to optimize patients' comfort, we developed a procedure combining minimally invasive intramedullary bone harvesting from the femur with arthroscopic tunnel refilling. METHODS: Patients with ACL reconstruction failure that were not eligible for one-step revision surgery but required tunnel refilling prior to the next ACL reconstruction were enrolled prospectively. Cancellous bone was harvested intramedullarily from the ipsilateral femur using the reamer-irrigator-aspirator system in a minimally invasive manner. Afterwards, the femoral and tibial tunnels were arthroscopically refilled using cones and push rods. Computer tomography (CT) analyses were carried out before and after the filling procedure. Pain levels were assessed during the entire follow-up. Patients undergoing iliac crest bone harvesting for other reasons served as a control group. Finally, the quality of the newly formed bone stock was evaluated in the subsequent ACL reconstruction procedure. RESULTS: Five patients were included during a 6-month period. Prior to refilling, tunnel analysis revealed a mean tunnel volume of 7.9 cm(3) at the femur [SD ± 5.3 cm(3)] and of 6.7 cm(3) [SD ± 5.1 cm(3)] at the tibia. The CT analyses further revealed that graft failure was predominantly caused by tunnel misplacement. Post-operatively, pain levels due to intramedullary bone harvesting were significantly lower compared to iliac crest bone harvesting at every analysed time point. Three to five months after tunnel filling, CT analyses showed sufficiently incorporated bone stocks with filling rates of 75 % femoral and 94 % tibial. ACL revision surgery was performed 4-5 months after tunnel filling without any complication. CONCLUSION: Intramedullary bone harvesting from the ipsilateral femur combined with arthroscopic refilling of the bone tunnels ensures a high-quality bone stock for further ACL reconstruction. The clinical relevance is shown by the feasibility of this technique and the significantly reduced pain levels during post-operative recovery.

[Treatment of tibial pseudoarthrosis. Complications after intramedullary, allogeneic fibular grafting]. / Behandlung zweier Tibiapseudarthrosen. Komplikationsbehafteter Verlauf nach intramedullären, allogenen Fibulatransplantaten.

A 24-year-old woman underwent cosmetic bilateral tibial lengthening with severe complications. In all, 15 operations, including allogeneic fibular grafting of both tibia, were required to treat unstable bilateral non-union, malalignment, and osteomyelitis of the right tibia.The present article describes the surgical strategy of revision to achieve good recovery with full consolidation and proper alignment of the lower leg. Furthermore, the indications for allogeneic bone grafting, which was described by Erich Lexer 100 years ago, are discussed. For surgical revision, a T-external fixator was used on the right leg, while a customized tibial nail was used on the left leg. Using these techniques, full consolidation and proper alignment was achieved. Allogeneic bone grafts in upper extremity defects cannot be recommended.