Active Motion Laboratory Test Apparatus for Evaluation of Total Elbow Prostheses

Purpose

The goal of this study was to develop a dynamic elbow testing apparatus that reproduces active joint motion at different shoulder positions to quantify the capabilities of total elbow arthroplasty designs.

Methods

We designed a testing apparatus to create active cyclic elbow joint motion in human cadaveric and sawbones composite upper extremities. Two pneumatic actuators recreated humerus-originating muscles while rubber bands simulated forearm muscle action. Arthroplasty durability was quantified through laxity assessment at predetermined cyclic loading intervals.

Results

Humeral forces were recorded in three specimens to generate active elbow motion at different degrees of shoulder abduction. The laxity in varus and valgus was measured as deflection between two fixed markers.

Conclusions

In vitro simulation of elbow biomechanics through active cyclic elbow motion at different degrees of shoulder abduction may characterize in vivo performance of total elbow arthroplasty.

Clinical relevance

Quantifying total elbow arthroplasty stability after cyclic loading in different shoulder positions may assist preclinical evaluation of arthroplasty designs.

Testing of Novel Total Elbow Prostheses Using Active Motion Experimental Setup

PURPOSE

The goal of this study was to test a novel uncemented and unconstrained total elbow arthroplasty (Kaufmann total elbow) design that is stabilized through a ligament reconstruction.

METHODS

We quantified the implant stability after 25,000 cycles, which represents the time between implantation and when ligament and bone healing has occurred. We used an active motion experimental setup that applies tendon loads via pneumatic cylinders and reproduces the forearm-originating dynamic stabilizers of the elbow. The novel total elbow arthroplasty was actuated for 5,000 full flexion-extension cycles at 5 different shoulder positions. Four Sawbones and 4 cadaver elbows were employed. Angular laxity and implant stability were recorded prior to testing and after each 5,000-loading cycle.

RESULTS

Four Sawbones and 4 cadaver elbows were implanted with the uncemented total elbow arthroplasty and did not demonstrate fixation failure or substantial laxity after 25,000 cycles of loading imparted at different shoulder positions.

CONCLUSIONS

Our findings demonstrate that the Kaufmann total elbow replacement implanted into cadaver and Sawbones specimens did not exhibit fixation failure or excessive laxity after 25,000 cycles.

CLINICAL RELEVANCE

An uncemented, nonmechanically linked total elbow arthroplasty that gains component fixation using intramedullary screws and employs a ligament reconstruction to stabilize the elbow has the potential to be a valuable management option, particularly in younger patients.

Strength of Humeral and Ulnar Intramedullary Screw Fixation

PURPOSE

The goal of this study was to test the pullout strength of intramedullary (IM) screws from within the humerus to establish their ability to seat an uncemented elbow arthroplasty.

METHODS

Six humerus and 6 ulna Sawbones specimens were drilled with a drill bit diameter of 5/16 inches, and the inner cortex was hand tapped for a ⅜-16 thread. A ⅜-16 custom-made titanium screw with an outer bolt diameter of 3/8 inches and 16 threads per inch was inserted by hand into the tapped holes. The specimens were then axially tensile loaded at a rate of 5 mm per minute until either the screw began to pull out from the bone or a fracture was noted.

RESULTS

Intramedullary screw fixation in the humerus achieved an average pullout strength of 1,439 pound-force (6,401 N), and IM screw fixation in the ulna achieved an average pullout strength of 882 pound-force (3,923 N). A fracture was noted in 3 humeral specimens, with 3 screws pulling out. In the ulna, the IM axial load caused a fracture in 5 specimens, and in 1 specimen, the screw pulled out.

CONCLUSIONS

Our findings demonstrate that IM screw fixation can create a tensile force within the screw that is greater than that required to generate the calculated level of compression between the implant and bone.

CLINICAL RELEVANCE

This may be beneficial in ensuring fixation between arthroplasty components and bone.

Influence of the COVID-19 pandemic on causes for the development of carbon monoxide intoxications

INTRODUCTION

Several causes can lead to carbon monoxide (CO) intoxication. A first-line treatment option for such intoxications is hyperbaric oxygenation (HBO2) therapy. The COVID-19 pandemic has been changing everyday life in Germany since March 2020, mainly caused by statutory provisions. Our aim was to review whether these changes have an influence on the causes and frequency for the development of CO intoxication.

METHODS

We retrospectively analyzed the data of patients who were treated for CO intoxication in our institution between April 2019 and March 2021. Besides demographic data, we compared the overall number and documented causes for each CO intoxication in the period of April 2020 to March 2021 with the period between April 2019 and March 2020.

RESULTS

After applying inclusion and exclusion criteria, 139 patients were included. We found a significant decrease in the overall number of patients who needed treatment since the beginning of the COVID-19 pandemic. However, the share of CO intoxication caused by the indoor use of coal stoves, coal barbecue, or suicide attempts increased. In contrast, the share of cases caused by apartment or house fire, smoking waterpipe, or gas stoves decreased.

CONCLUSION

The COVID-19 pandemic and the associated restrictions lead to a significant reduction in the number of patients in need for HBO2 therapy due to CO-Intoxication. The causes leading to CO intoxication also changed since the beginning of the COVID-19 pandemic. We observed a shift toward causes related to the indoor use of coal-fired stoves and barbecues as well as suicide attempts.

Hyperoxia and the cardiovascular system: experiences with hyperbaric oxygen therapy

Hyperoxia has been described to induce bradycardia by direct stimulation of the parasympathetic nervous system. Also, hyperoxia has been found to increase blood pressure by an elevation of vascular resistance. However, the latter effect itself would induce bradycardia by baroreceptor stimulation. This single-arm monocentric retrospective study aims to evaluate the correlation between these effects by investigating the relation between oxygen (O₂) administration and heart rate over time. Data were collected from 23 patients without cardiovascular problems undergoing hyperbaric oxygen therapy (2.4 bar) retrospectively. During single oxygen bouts, transcutaneously measured partial pressure of O₂ was increased. During this surge of oxygen pressure, the arterial blood pressure was increased while the heart rate was decreased. Respiration rate was maintained independently from breathing 100% O₂ or air. During single oxygen bouts, the half-life of transcutaneously measured partial pressure of O₂ was 5.4 ± 2.1 mmHg/s, and the half-life of heart rate was 0.45 ± 0.19 beats/min. It has been shown that hyperbaric oxygen therapy increases the transcutaneously measured partial pressure of O₂. This increase was rather fast, followed by a rather slow decrease in HR. This finding does not support direct vagal activation. Heart rate is not decreased due to a direct vagal activation during hyperbaric oxygen therapy. Our single-arm, retrospective study has additionally confirmed that oxidative stress injures the endothelium, and the reduced endothelial-derived vasodilators cause vasoconstriction. As a consequence, blood pressure increases, and heart rate is then further decreased via the baroreceptor reflex.

An Updated Narrative Review on Ergometric Systems Applied to Date in Assessing Divers' Fitness

Many recreational divers suffer medical conditions, potentially jeopardizing their safety. To scale down risks, medical examinations are mandatory and overwhelmingly performed using bicycle ergometry, which overlooks some important aspects of diving. Searching ergometric systems that better address the underwater environment, a systematic literature search was conducted using the keywords 'diving', 'fitness', 'ergometry', and 'exertion'. All presented alternative systems found convincingly describe a greatly reduced underwater physical performance. Thus, if a diver's workload in air should already be limited, he/she will suffer early from fatigue, risking a diving incident. How to assess fitness? Performance diagnostics in sports is always specific for a modality or movement. Therefore, professional scuba divers should be tested when fin-swimming underwater. For the vast number of recreational divers, the current screening can likely not be replaced. However, to prevent accidents, divers need to understand and be able to improve factors that limit their physical performance underwater. Other systems, presented here, will continue to be important tools in underwater research.

Doctor, when can I drive? - Range of functional ankle motion during driving

BACKGROUND

Driving a motor vehicle needs a specific joint mobility and yet only limited knowledge exists regarding the necessary ankle range of motion. The goal of this study is to characterize the sequence and range of ankle motion.

METHODS

The arc of plantarflexion/dorsiflexion and supination/pronation was recorded in the right and left ankle using electrogoniometers while thirty laps were driven by fifteen healthy participants around a course in a manual transmission car with a left sided steering wheel. The driver was required to perform the following maneuvers during each lap: (I) Vehicle acceleration and gear change, (II) Sudden evasion, (III) Routine turning, (IV) Rapid turning, (V) Vehicle acceleration followed by emergency braking.

RESULTS

Driving required the right ankle to plantarflex 13±9 and dorsiflex 22±7 while supinating 15±7 degrees and pronating minimally. The left ankle plantarflexed 19±10and dorsiflexed 17±10 while supinating 15±7 degrees and pronating minimally. The right ankle dorsiflexed significantly more (p=0.00), and yet the left ankle had a significantly higher maximum plantarflexion and range of plantarflexion/dorsiflexion (p=0.00). Emergency braking resulted in a significantly higher maximum plantarflexion as well as plantarflexion/dorsiflexion range when compared to other maneuvers.

CONCLUSION

This study describes the range of ankle motion identified to drive a car with a manual transmission and a left-sided steering wheel. The right and left ankle exhibit different arcs of motion during driving. This knowledge may assist when evaluating a patient's driving capability. Further studies are needed to investigate whether movement restrictions impair driving.

LEVEL OF EVIDENCE

Basic science study.

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.

Total Elbow Arthroplasty: Elbow Biomechanics and Failure

Total elbow arthroplasty (TEA) has lower revision-free survivorship than other major joint replacement. Despite this, elbow replacement has remained popular. Surgical technique for TEA destabilizes the elbow by removing the medial and lateral collateral ligaments and, frequently, the radiocapitellar articulation. Current semiconstrained implants aim to allow for physiological varus and valgus motion by employing a sloppy hinge; however, over time, these designs fail owing to nonanatomic force transmission. Nonanatomic force transmission results from ligament release, force transmission primarily to the humeral and ulnar shafts, and radial head resection. These altered biomechanics may be the source of complications seen in semiconstrained arthroplasty. These complications perpetuate the cycle of failure and ultimately have poor salvage options.

Neutral or Natural? Functional Impact of the Coronal Alignment in Total Knee Arthroplasty

Total knee arthroplasty (TKA) is a very successful procedure. The alignment in TKA has been identified as being of importance to prevent early implant failure and patient dissatisfaction. Our hypothesis was that patients with a preoperative varus deformation remaining in a slight varus alignment as their natural alignment after TKA will have superior clinical results compared with patients who are restored in neutral alignment. A total of 115 patients were corrected from varus to neutral (varus-neutral) and in 33 patients a preoperative varus alignment was kept in varus (varus). Standardized preoperative and postoperative full-length hip-knee-ankle radiographs under full weight-bearing conditions were performed in all patients. The patients' knees were categorized preoperatively and postoperatively based on the angle between mechanical femoral axis and mechanical tibial axis. Knees with alignment between ± 3 degrees were categorized as neutrally aligned, whereas alignment within ≤ -3 degrees was categorized as varus. The Knee Injury Osteoarthritis Outcome Score (KOOS) and Oxford Knee Score were determined retrospectively. The varus group scored significantly better in total KOOS (p < 0.05) compared with the varus-neutral group. Also, a trend was visible in the Oxford Knee Score but this was not significant (p > 0.05). This trend was even more evident in varus knees which were slightly undercorrected. The results support the assumption that leaving a residual varus alignment after TKA leads to better functional outcomes in TKA for patients with preoperative varus osteoarthritis.

Doctor, when can I drive?-the range of elbow motion while driving a car

BACKGROUND

Immobilization of the upper extremity after an acute injury or postoperatively affects an individual's ability to safely operate a motor vehicle. The elbow is particularly sensitive to immobilization, with subsequent stiffness leading to functional limitations. Most activities of daily living are successfully achieved within a "functional arc" of elbow motion between 30° and 130° of flexion. No objective guidelines exist regarding the range of motion needed to safely operate a vehicle. In this study, we measured the range of motion of right and left elbows while driving a manual-transmission car.

MATERIALS AND METHODS

Using electro-goniometers, we measured the flexion and extension, as well as pronation and supination, of the right and left elbows in 20 healthy, right hand-dominant subjects while driving a car. These measurements were recorded on (1) city streets, (2) country roads, and (3) highways.

RESULTS

For city streets, the range of motion in terms of flexion and pronation/supination was 15°-105° and 0°-45°/0°-35°, respectively, for the right elbow and 20°-95° and 0°-45°/0°-40°, respectively, for the left. For country roads, it was 10°-100° and 0°-40°/0°-35°, respectively, for the right elbow and 20°-95° and 0°-30°/0°-30°, respectively, for the left. For highways, it was 5°-100° and 0°-40°/0°-35°, respectively, for the right elbow and 20°-90° and 0°-30°/0°-25°, respectively, for the left. Mean pronation was significantly higher for the right elbow (P < .01).

CONCLUSION

This study describes the range of elbow motion identified to drive a car with a manual transmission and a left-sided steering wheel. Mean pronation of the right elbow is significantly higher than that of the left. Further studies are needed to investigate the relevance of movement restrictions as they relate to handedness, steering-wheel side, and driving impairment.

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.

Primary cemented bipolar radial head prostheses for acute elbow injuries with comminuted radial head fractures: mid-term results of 37 patients

BACKGROUND

Radial head arthroplasty represents a widely accepted treatment for elbow injuries with non-reconstructible radial head fractures. The aim of this retrospective multicenter study was to assess mid-term results of patients with clearly defined elbow injuries including type III fractures of the radial head according to Mason's classification type III after primary arthroplasty using a cemented bipolar design.

MATERIALS AND METHODS

In 45 cases a primary cemented bipolar arthroplasty of the radial head was implanted for elbow injuries combined with an acute Mason type III radial head fracture. In all patients associated fractures were detected with preoperative CT scans and ligamentous injuries were evaluated and both were addressed intraoperatively based on a standardized algorithm. Patients with associated injuries other than coronoid fractures and collateral ligament tears were excluded from this study to obtain a more homogenous sample. Clinical and radiological assessment was performed on thirty-seven patients at an average of 5.6 years postoperatively.

RESULTS

DASH Score, functional rating index of Broberg and Morrey, Mayo Elbow Performance Score, and Mayo Modified Wrist Score confirmed good-to-excellent results in most of the patients. Compared to the unaffected arm range of motion and grip strength were slightly reduced. No elbow instability or loosening of the prosthesis, and minor degenerative changes were detected in a few cases.

CONCLUSION

Primary cemented bipolar arthroplasty for type III fractures according to Mason's classification in an elbow injury pattern only including associated coronoid fractures and/or ligamentous tears resulted in good-to-excellent mid-term results. These results suggest that primary bipolar radial head arthroplasty combined with distinct treatment of all associated injuries provides good functional outcomes concerning range of motion, elbow stability, and strength in this cohort. However, the associated injuries may influence clinical and radiological outcome and need to be detected, classified, and treated carefully.

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.

Influences of donor and host age on human muscle-derived stem cell-mediated bone regeneration

Background

Human muscle-derived stem cells (hMDSCs) have been shown to regenerate bone efficiently when they were transduced with Lenti-viral bone morphogenetic protein 2 (LBMP2). However, whether the age of hMDSCs and the animal host affect the bone regeneration capacity of hMDSCs and mechanism are unknown which prompted the current study.

Methods

We isolated three gender-matched young and old populations of skeletal muscle stem cells, and tested the influence of cells’ age on in vitro osteogenic differentiation using pellet culture before and after Lenti-BMP2/green fluorescent protein (GFP) transduction. We further investigated effects of the age of hMDSCs and animal host on hMDSC-mediated bone regeneration in a critical-size calvarial bone defect model in vivo. Micro-computer tomography (CT), histology, and immunohistochemistry were used to evaluate osteogenic differentiation and mineralization in vitro and bone regeneration in vivo. Western blot, quantitative polymerase chain reaction (PCR), and oxidative stress assay were performed to detect the effects of age of hMDSCs on cell survival and osteogenic-related genes. Serum insulin-like growth factor 1 (IGF1) and receptor activator of nuclear factor-kappa B ligand (RANKL) were measured with an enzyme-linked immunosorbent assay (ELISA).

Results

We found LBMP2/GFP transduction significantly enhanced osteogenic differentiation of hMDSCs in vitro, regardless of donor age. We also found old were as efficient as young LBMP2/GFP-transduced hMDSCs for regenerating functional bone in young and old mice. These findings correlated with lower phosphorylated p38MAPK expression and similar expression levels of cell survival genes and osteogenic-related genes in old hMDSCs relative to young hMDSCs. Old cells exhibited equivalent resistance to oxidative stress. However, both young and old donor cells regenerated less bone in old than young hosts. Impaired bone regeneration in older hosts was associated with high bone remodeling due to higher serum levels of RANKL and lower level of IGF-1.

Conclusion

hMDSC-mediated bone regeneration was not impaired by donor age when hMDSCs were transduced with LBMP2/GFP, but the age of the host adversely affected hMDSC-mediated bone regeneration. Regardless of donor and host age, hMDSCs formed functional bone, suggesting a promising cell resource for bone regeneration.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-1066-z) contains supplementary material, which is available to authorized users.

The challenge of Monteggia-like lesions of the elbow

Aims

The aim of this retrospective multicentre study was to evaluate mid-term results of the operative treatment of Monteggia-like lesions and to determine the prognostic factors that influence the clinical and radiological outcome.

Patients and Methods

A total of 46 patients (27 women and 19 men), with a mean age of 57.7 years (18 to 84) who had sustained a Monteggia-like lesion were followed up clinically and radiologically after surgical treatment. The Mayo Modified Wrist Score (MMWS), Mayo Elbow Performance Score (MEPS), Broberg and Morrey Score, and Disabilities of the Arm, Shoulder and Hand (DASH) score were used for evaluation at a mean of 65 months (27 to 111) postoperatively. All ulnar fractures were stabilized using a proximally contoured or precontoured locking compression plate. Mason type I fractures of the radial head were treated conservatively, type II fractures were treated with reconstruction, and type III fractures with arthroplasty. All Morrey type II and III fractures of the coronoid process was stabilized using lag screws.

Results

Good results were found for the MMWS, with a mean of 88.4 (40 to 100). There were 29 excellent results (63%), nine good (20%), seven satisfactory (15%), and one poor (2%). Excellent results were obtained for the MEPS, with a mean of 90.7 (70 to 100): 31 excellent results (68%), 13 good (28%), and two fair (4%). Good results were also found for the functional rating index of Broberg and Morrey, with a mean score of 86.6 (57 to 100). There were 16 excellent results (35%), 22 good (48%), six fair (13%), and two poor (4%). The mean DASH score was 15.1 (0 to 55.8). Two patients had delayed wound healing; four patients had nonunion requiring bone grafting. One patient had asymptomatic loosening of the radial head prosthesis.

Conclusion

Monteggia-like lesions are rare. With correct identification, classification, and understanding using CT scans followed by appropriate surgical treatment that addresses all components of the injury, good to excellent mid-term results can be achieved. Cite this article: Bone Joint J 2018;100-B:212–18.

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.

Molecular- and microarray-based analysis of diversity among resting and osteogenically induced porcine mesenchymal stromal cells of several tissue origin

Mesenchymal stromal cells (MSCs) play a pivotal role in modern therapeutic approaches in bone‐healing disorders. Although bone marrow‐derived MSCs are most frequently used, the knowledge that many other adult tissues represent promising sources for potent MSCs has gained acceptance. In the present study, the osteogenic differentiation potential of porcine skin fibroblasts (FBs), as well as bone marrow‐ (BMSCs), adipose tissue‐ (ASCs) and dental pulp‐derived stromal cells (DSCs) were evaluated. However, additional application of BMP‐2 significantly elevated the delayed osteogenic differentiation capacity of ASC and FB cultures, and in DSC cultures the supplementation of platelet‐rich plasma increased osteogenic differentiation potential to a comparable level of the good differentiable BMSCs. Furthermore, microarray gene expression performed in an exemplary manner for ASCs and BMSCs revealed that ASCs and BMSCs use different gene expression patterns for osteogenic differentiation under standard media conditions, as diverse MSCs are imprinted dependent from their tissue niche. However, after increasing the differentiation potential of ASCs to a comparable level as shown in BMSCs, a small subset of identical key molecules was used to differentiate in the osteogenic lineage. Until now, the importance of identified genes seems to be underestimated for osteogenic differentiation. Apparently, the regulation of transmembrane protein 229A, interleukin‐33 and the fibroblast growth factor receptor‐2 in the early phase of osteogenic differentiation is needed for optimum results. Based on these results, bone regeneration strategies of MSCs have to be adjusted, and in vivo studies on the osteogenic capacities of the different types of MCSs are warranted. Copyright © 2016 The Authors Tissue Engineering and Regenerative Medicine published by John Wiley & Sons, Ltd.

Bone Marrow Aspirate Concentrate in Combination With Intravenous Iloprost Increases Bone Healing in Patients With Avascular Necrosis of the Femoral Head: A Matched Pair Analysis

With disease progression, avascular necrosis (AVN) of the femoral head may lead to a collapse of the articular surface. The exact pathophysiology of AVN remains unclear, although several conditions are known that can result in spontaneous cell death, leading to a reduction of trabecular bone and the development of AVN. Hip AVN treatment is stage-dependent in which two main stages of the disease can be distinguished: pre-collapse (ARCO 0-II) and post-collapse stage (ARCO III-IV, crescent sign). In the pre-collapse phase, core decompression (CD), with or without the addition of bone marrow (e.g. bone marrow aspirate concentrate, BMAC) or bone graft, is a common treatment alternative. In the post-collapse phase, THA (total hip arthroplasty) must be performed in most of the patients. In addition to surgical treatment, the intravenous application of Iloprost has been shown to have a curative potential and analgesic effect. From October 2009 to October 2014, 49 patients with AVN (stages I-III) were treated with core decompression at our institution. All patients were divided into group A (CD + BMAC) and group B (CD alone). Of these patients, 20 were included in a matched pair analysis. The patients were matched to age, gender, ARCO-stage, Kerboul combined necrotic angle, the cause of AVN, and whether Iloprost-therapy was performed. The Merle d’Aubigné Score and the Kerboul combined necrotic angle in a-p and lateral radiographs were evaluated pre- and postoperatively. The primary endpoint was a total hip arthroplasty. In group A, two patients needed THA while in group B four patients were treated with THA. In group A, the Merle d’Aubigné Score improved from 13.5 (pre-operatively) to 15.3 (postoperatively). In group B there was no difference between the pre- (14.3) and postoperative (14.1) assessment. The mean of the Kerboul angle showed no difference in both groups compared pre- to postoperatively (group A: pre-op 212°, postop 220°, group B: pre-op 213, postop 222°). Regarding radiographic evaluation, the interobserver variability revealed a moderate agreement between two raters regarding the pre-(ICC 0.594) and postoperative analysis (ICC 0.604).This study demonstrates that CD in combination with the application of autologous bone marrow aspirate concentrate into the femoral head seems to be a safe and efficient treatment alternative in the early stages of AVN of the femoral head when compared to CD alone.

Synergistic effects of HBO and PRP improve bone regeneration with autologous bone grafting

Bone defects remain a challenge for patients and orthopaedic surgeons. Autologous transfer of cancellous bone grafts remains the standard of care. However, in recent years various osteoinductive substitute materials, such as platelet rich plasma (PRP) and hyperbaric oxygen therapy (HBO) have been shown to improve bone healing. This study evaluates the effects of a combined application of PRP and HBO with autologous bone grafting in an animal model. In 48 New Zealand White rabbits bone defects at the radius were filled with autologous bone harvested at the iliac crest. This was combined with application of autologous PRP and/or HBO treatment for the duration of this study. After 3 and 6 weeks histomorphometric, immunohistochemical and radiologic evaluations were performed. All animals tolerated the treatment well. Improved bone regeneration was shown in all groups at 6 weeks compared to 3 weeks. Additional application of PRP and HBO resulted in an increase in new bone formation and increased neovascularization at 3 and 6 weeks. There was no statistical significant difference between PRP and HBO application in these regards. A combinatory use of PRP and HBO resulted in an increased bone regeneration and neovascularization compared to all other groups. This study provides evidence for an improvement of bone regeneration with the combinatory application of PRP and HBO to autologous cancellous bone grafts in a model of weight bearing bone defects in rabbits. Also synergistic effects of these two measures on angiogenesis were evident.

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.

Characterization of a compartment syndrome-like injury model

INTRODUCTION

Acute compartment syndrome (CS) is caused by an elevation of pressure within a muscular compartment that can be caused by numerous factors, including blunt trauma. In this study, we characterized a rodent model of CS-like injury.

METHODS

Forty male athymic rats received a standardized injury of ischemia and compression to their hindlimbs, while the intracompartmental pressure (ICP) was measured using an implantable transmitter. Tetanic muscle function was evaluated, and histology was performed on the tibialis anterior (TA) muscle.

RESULTS

ICPs were held at 260.70 ± 2.70 mm Hg during injury. Injured muscles recovered 59% of their total function 4 weeks after injury, and histology showed high levels of edema, inflammation (CD68(+) ), angiogenesis (CD31(+) ), and fibrosis within 72 hours after injury.

CONCLUSIONS

We describe a novel CS-like injury model and a novel method to measure ICP, which could potentially be used to develop innovative therapies to manage CS injury in patients.

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.

The composite of bone marrow concentrate and PRP as an alternative to autologous bone grafting

One possible alternative to the application of autologous bone grafts represents the use of autologous bone marrow concentrate (BMC). The purpose of our study was to evaluate the potency of autologous platelet-rich plasma (PRP) in combination with BMC. In 32 mini-pigs a metaphyseal critical-size defect was surgically created at the proximal tibia. The animals were allocated to four treatment groups of eight animals each (1. BMC+CPG group, 2. BMC+CPG+PRP group, 3. autograft group, 4. CPG group). In the BMC+CPG group the defect was filled with autologous BMC in combination with calcium phosphate granules (CPG), whereas in the BMC+CPG+PRP group the defect was filled with the composite of autologous BMC, CPG and autologous PRP. In the autograft group the defect was filled with autologous cancellous graft, whereas in the CPG group the defect was filled with CPG solely. After 6 weeks radiological and histomorphometrical analysis showed significantly more new bone formation in the BMC+CPG+PRP group compared to the BMC+CPG group and the CPG group. There were no significant differences between the BMC+CPG+PRP group and the autograft group. In the PRP platelets were enriched significantly about 4.7-fold compared to native blood. In BMC the count of mononuclear cells increased significantly (3.5-fold) compared to the bone marrow aspirate. This study demonstrates that the composite of BMC+CPG+PRP leads to a significantly higher bone regeneration of critical-size defects at the proximal tibia in mini-pigs than the use of BMC+CPG without PRP. Furthermore, within the limits of the present study the composite BMC+CPG+PRP represents a comparable alternative to autologous bone grafting.

A comparison of bone regeneration with human mesenchymal stem cells and muscle-derived stem cells and the critical role of BMP

Adult multipotent stem cells have been isolated from a variety of human tissues including human skeletal muscle, which represent an easily accessible source of stem cells. It has been shown that human skeletal muscle-derived stem cells (hMDSCs) are muscle-derived mesenchymal stem cells capable of multipotent differentiation. Although hMDSCs can undergo osteogenic differentiation and form bone when genetically modified to express BMP2; it is still unclear whether hMDSCs are as efficient as human bone marrow mesenchymal stem cells (hBMMSCs) for bone regeneration. The current study aimed to address this question by performing a parallel comparison between hMDSCs and hBMMSCs to evaluate their osteogenic and bone regeneration capacities. Our results demonstrated that hMDSCs and hBMMSCs had similar osteogenic-related gene expression profiles and had similar osteogenic differentiation capacities in vitro when transduced to express BMP2. Both the untransduced hMDSCs and hBMMSCs formed very negligible amounts of bone in the critical sized bone defect model when using a fibrin sealant scaffold; however, when genetically modified with lenti-BMP2, both populations successfully regenerated bone in the defect area. No significant differences were found in the newly formed bone volumes and bone defect coverage between the hMDSC and hBMMSC groups. Although both cell types formed mature bone tissue by 6 weeks post-implantation, the newly formed bone in the hMDSCs group underwent quicker remodelling than the hBMMSCs group. In conclusion, our results demonstrated that hMDSCs are as efficient as hBMMSCs in terms of their bone regeneration capacity; however, both cell types required genetic modification with BMP in order to regenerate bone in vivo.

Fixation of multifragmentary patella fractures using a bilateral fixed-angle plate

This biomechanical study is the first to compare 3 fixation methods-bilateral fixed-angle plate, modified anterior tension wiring, and cannulated lag screws with anterior tension wiring-in multifragmentary distal patella fractures. A T-shaped 3-part fracture simulating a multifragmentary articular distal patella fracture (AO/OTA 34-C2.2) was created in 18 human cadaver knee specimens. Three groups were created using homogenous ages and bone mineral densities based on the fixation method received. Repetitive testing over 100 cycles was performed by moving the knee against gravity from 90° flexion to full extension. Failure was defined as fracture displacement greater than 2 mm. In all patellae using fixed-angle plates, an anatomical fracture reduction could be maintained throughout cyclic testing, whereas anterior tension wiring and lag screws with tension wiring showed significant fracture displacement after 100 cycles, with mean fracture gaps of 2.0±1.3 and 1.9±1.6 mm, respectively. The differences in fracture gaps between the fixed-angle plate group and the other 2 groups were statistically significant. In both groups using tension wiring, half of the constructs (3 of 6 in each group) failed due to a fracture displacement greater than 2 mm. The bilateral fixed-angle plate was the only fixation method that sustainably stabilized a multifragmentary articular distal patella fracture during cyclic loading when compared with modified anterior tension wiring and cannulated lag screws with anterior tension wiring.

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.

Bone marrow aspiration concentrate and platelet rich plasma for osteochondral repair in a porcine osteochondral defect model

BACKGROUND

Bone marrow aspiration concentrate (BMAC) may possess a high potency for cartilage and osseous defect healing because it contains stem cells and multiple growth factors. Alternatively, platelet rich plasma (PRP), which contains a cocktail of multiple growth factors released from enriched activated thrombocytes may potentially stimulate the mesenchymal stem cells (MSCs) in bone marrow to proliferate and differentiate.

METHODS

A critical size osteochondral defect (10×6 mm) in both medial femoral condyles was created in 14 Goettinger mini-pigs. All animals were randomized into the following four groups: biphasic scaffold alone (TRUFIT BGS, Smith & Nephew, USA), scaffold with PRP, scaffold with BMAC and scaffold in combination with BMAC and PRP. After 26 weeks all animals were euthanized and histological slides were cut, stained and evaluated using a histological score and immunohistochemistry.

RESULTS

The thrombocyte number was significantly increased (p = 0.049) in PRP compared to whole blood. In addition the concentration of the measured growth factors in PRP such as BMP-2, BMP-7, VEGF, TGF-β1 and PDGF were significantly increased when compared to whole blood (p<0.05). In the defects of the therapy groups areas of chondrogenic tissue were present, which stained blue with toluidine blue and positively for collagen type II. Adding BMAC or PRP in a biphasic scaffold led to a significant improvement of the histological score compared to the control group, but the combination of BMAC and PRP did not further enhance the histological score.

CONCLUSIONS

The clinical application of BMAC or PRP in osteochondral defect healing is attractive because of their autologous origin and cost-effectiveness. Adding either PRP or BMAC to a biphasic scaffold led to a significantly better healing of osteochondral defects compared with the control group. However, the combination of both therapies did not further enhance healing.

Determination of the amount of leg length inequality that alters spinal posture in healthy subjects using rasterstereography

PURPOSE

Leg length inequalities (LLIs) can result in an increased energy consumption, abnormal gait or osteoarthritis of the hip. In a previous study we simulated different LLIs of up to 15 mm and evaluated their effects on the pelvic position and spinal posture. We found a correlation between LLIs and resulting changes of the pelvic position. Despite suggestions in the literature we were not able to detect significant changes of the spinal posture. Therefore, the purpose of this study was to determine the amount of LLI that would in fact alter the spinal posture.

METHODS

The subjects were placed on a simulation platform, whose height could be precisely controlled by the measuring device, to simulate different LLIs of up to 20 mm. For LLIs >20 mm, additional precision-cut wooden blocks were used under one foot. After an adaptation period the resulting changes of the pelvis and spine were measured with a rasterstereographic device.

RESULTS

We found a significant correlation between platform height changes and changes of the pelvic position. The frontal spinal parameters surface rotation and lateral deviation changed significantly when simulating differences greater than 20 mm. No changes of the sagittal spinal curvature were measured, however, a trend to decreasing kyphotic angles was noted.

CONCLUSIONS

Our study has shown for the first time that LLIs >20 mm will lead to significant changes in the spinal posture of healthy test subjects. However, these changes were only found in frontal (surface rotation and lateral flexion) spinal parameters, but not in sagittal parameters. Here for the kyphotic angle only a tendency to decreasing angles was noted. We have also found a significant correlation between different leg lengths and changes of the pelvic position. Further, females and males seem to react in the same way to LLIs.

Cyclic long-term loading of a bilateral fixed-angle plate in comparison with tension band wiring with K-wires or cannulated screws in transverse patella fractures

PURPOSE

A bilateral fixed-angle plate was biomechanically compared to the two currently preferred methods of osteosynthesis for transverse patella fractures. It was hypothesized that the new angle-stable implant would provide a secure and sustainable fracture fixation, superior to the established standard techniques.

METHODS

Twenty-one identical patellae made of polyurethane foam (Sawbones(®)), osteotomized to create a transverse two-part fracture, were fixed with modified anterior tension wiring, cannulated lag screws with anterior tension wiring or bilateral polyaxial 2.7-mm fixed-angle plates. The testing protocol consisted of 10,000 repetitive cycles using a non-destructive physiological load between 100 and 300 N at a simulated knee flexion of 60°.

RESULTS

All 21 Sawbone(®)-patellae sustained repetitive loading up to 10,000 cycles without failing. The anterior tension wire group displayed significant displacement of the fracture gap (0.7 ± 0.2 mm) during cyclic loading, while both lag screws with tension wiring and bilateral fixed-angle plates showed no fracture gap widening at all (p < 0.01).

CONCLUSION

The bilateral fixed-angle plate and cannulated lag screws with anterior tension wiring preserved a constantly reduced fracture gap over 10,000 tensile cycles in contrast to modified anterior tension wiring, which exhibited significant widening of the gap after initial loading. Results of in vitro testing indicate that bilateral fixed-angle plates provide sustainable fixation stability offering a promising new option in the treatment for transverse patella fractures.

[Interhospital transfer of severely injured patients in Germany. Evaluation of the DGU trauma register]

BACKGROUND

The TraumaNetzwerk(D) DGU was founded 3 years ago and since then the majority of trauma centers have been registered and organized into regional trauma network services (TNW). Within these networks assessment criteria for transferring patients to higher level hospitals are defined. The purpose of this study was to evaluate the incidence, causes, implications and quality of care for patients with major trauma who were transferred for definitive treatment before implementation of the TraumaNetzwerk(D) DGU in Germany.

PATIENT AND METHODS

The data of 19,035 patients listed in the German Trauma Register of the German Society for Trauma Surgery (DGU, 2002-2007) were analyzed. Patients with an injury severity score (ISS) >9 and a blood pressure documented on admission were included into the study. Data were allocated according to patients where therapy was performed completely in the primary hospital of admission (group I; n=16,033; 84.2%) and patients transferred after primary care from one hospital to another centre for definitive care (group II; n=3,002; 15.8%). Comparative parameters were the pattern and severity of injury, physiological state on admission and clinical outcome.

RESULTS

Mean ISS and percentage of patients with an ISS ≥25 did not differ significantly between groups. Of the patients who were transferred to a higher level trauma centre (group II) 20.7% needed catecholamines on admission, 10.1% were in shock (blood pressure <90 mmHg) and 2.5% of the patients underwent resuscitation in the emergency department. Patients of group II had a considerably longer hospital stay (31.2±35.5 days) than patients of group I (24.8±27.1 days). Furthermore, treatment costs were significantly higher for group II (I: EUR 23,870; II: EUR 26,054).

CONCLUSIONS

A relevant percentage of patients transferred from one hospital to another were hemodynamically and clinically unstable. To what extent the quality of patient transfer and therefore major trauma care is improved by the implementation of regional trauma networks in Germany remains to be seen over the next years.

The impact of arterial hypertension on polytrauma and traumatic brain injury

BACKGROUND

Pre-hospital hypotension in trauma patients is associated with high mortality. Especially for patients with severe traumatic brain injury (TBI), arterial normotension or even hypertension (AHT) is considered an important mechanism for sustaining adequate cerebral perfusion pressure. The effect of pre-hospital arterial hypertension (pAHT) on in-hospital mortality after trauma has not been studied to date.

METHODS

We retrospectively analyzed data in the trauma registry of the German Society for Trauma Surgery (DGU) on all trauma patients in Germany from 1993 to 2008 who were 16 to 80 years old at the time of the trauma and had an injury severity score (ISS) of 9 or above (total, 42 500 patient data sets). For the analysis, we divided the patients into two groups: those with and those without TBI. We further divided the TBI patients into five subgroups depending on the course of their systolic blood pressure up to the moment of their arrival at the hospital. We also analyzed the patients' demographic data, patterns of injury, and accident mechanisms.

RESULTS

Trauma patients with TBI and pAHT (142 of 561 patients) had a significantly higher mortality than normotensive TBI patients (25.3% vs. 13.5%, p<0.001). Arterial hypertension that either rises or falls before the patient reaches the hospital is associated with higher in-hospital mortality. A logistical regression analysis of 5384 patients revealed that patients with pAHT (n = 561) had an odds ratio of 1.9 (95% confidence interval, 1.4 to 1.6) for death in the hospital compared to normotensive patients (n = 6020).

CONCLUSION

Systolic blood pressure values above 160 mm Hg before arrival in the hospital worsen the outcome of trauma patients with TBI.

Biomechanical stability of different suture fixation techniques for tibial eminence fractures

PURPOSE

Displaced tibial eminence fractures require surgical fixation in order to obtain a stable knee joint. Suture fixation with FiberWire(®) seems to be the most favorable therapeutic option. Biomechanical studies show failure of this technique most commonly due to a suture cutout with subsequent fracture of the tibial eminence fragment. The goal of this study is to compare the biomechanical properties of three different techniques of suture fixation using FiberWire(®).

METHODS

Bone mineral density was evaluated in 18 human knee specimens by pqCT, and three similar groups were formed. A standardized anterior tibial eminence fracture was created, and suture fixation was performed using one of three different techniques in 6 specimens each. Cyclic and destructive testing was conducted.

RESULTS

Significant differences between the three techniques could be shown neither in the cycles needed to achieve a steady state nor in a failure load or initial stiffness. Almost all specimens failed by suture cutout.

CONCLUSION

The presented modification of the existing technique for suture fixation of tibial eminence fractures did not lead to an increased initial stability nor did it lower the rate of suture cutout. All tested suture techniques showed comparable initial stiffness and failure load.

Biomechanical cadaver testing of a fixed-angle plate in comparison to tension wiring and screw fixation in transverse patella fractures

INTRODUCTION

Operative treatment of patella fractures is frequently associated with implant failure and secondary dislocation which can be attributed to the employed hardware. Therefore, a 2.7 mm fixed-angle plate designed for the treatment of patella fractures was tested biomechanically against the currently preferred methods of fixation. It was hypothesized that under simulated cyclic loading fixed-angle plating would be superior to modified anterior tension wiring or cannulated lag screws with anterior tension wiring.

MATERIALS AND METHODS

Eighteen human cadaver knees, matched by bone mineral density and age, were divided into three groups of six. After setting a transverse patella fracture each group received one of the osteosyntheses mentioned above. Repetitive testing over 100 cycles was performed at non-destructive loads by simulating knee motion from 90° flexion to full extension.

RESULTS

Anterior tension wiring as well as lag screws with tension wiring showed significant fracture displacement after the initial cycle already. Both constructs, lag screws plus wiring (3.7 ± 2.7 mm) as well as tension wiring alone (7.1 ± 2.2 mm) displayed fracture displacement of >2 mm which is clinically regarded as failure. Those patellae stabilized with fixed-angle plates showed no significant fracture gap widening after completion of 100 cycles (0.7 ± 0.5 mm). The differences between the fixed-angle plate group and the other two groups were statistically significant (p<0.05).

CONCLUSION

In contrast to modified anterior tension wiring and cannulated lag screws with anterior tension wiring the bilateral fixed-angle plate was the only fixation device to stabilize transverse patella fractures securely and sustainably.

Decreasing mortality after femoral neck fracture treated with bipolar hemiarthroplasty during the last twenty years

PURPOSE

The aim of our study was to investigate trends over time in the mortality of elderly patients after femoral neck fractures treated with bipolar hemiarthroplasty.

METHODS

Altogether 487 cases of femoral neck fracture treated with bipolar hemiarthroplasty were observed during a 20-year period. Mortality rates were calculated for five years postoperatively. To account for the age distribution of the study population standardised mortality ratios (SMR) with respect to the age-specific mortality of the German population were determined and compared. Additional changes of the SMRs over time and the influence of the time delay before surgery on long-term mortality were evaluated.

RESULTS

Femoral neck fractures treated with bipolar hemiendoprosthesis have a significant impact on mortality. Postoperative mortality is increased in patients of all age groups, but the effect diminishes in higher age groups. The influence on mortality was significantly greater for men than for women. The SMR has decreased from 3.52 before 1995 to 1.2 after 2006. Since 2006 there is no longer an increase in mortality after surgical treatment of a femoral neck fracture compared to general German population of the same age.

CONCLUSION

Femoral neck fractures treated with bipolar hemiendoprosthesis result in a significantly increased mortality, however in our population this impact has significantly decreased over time. The effect on mortality is less in women and higher age groups than in men and younger patients. No influence of the time between accident and surgery on mortality could be detected.

[Treatment strategy for carpometacarpal fracture dislocation]

Carpometacarpal (CMC) fracture dislocations of the 2nd through 5th ray are rare injuries whose extent is regularly underestimated in the initial radiographic evaluation of the hand. Obtaining a computed tomography scan is imperative due to the radiographic underrepresentation of the full bone and joint injury. Restoration of bone and joint anatomy of the affected region is of paramount import to prevent joint deterioration and loss of hand durability and dexterity. Early surgical intervention can lead to good functional results. Different operative treatment strategies exist with a common approach being Kirschner wire, screw or plate fixation after closed or open fracture reduction and joint relocation.

Initial stability of two different adhesives compared to suture repair for acute Achilles tendon rupture--a biomechanical evaluation

PURPOSE

Treatment of acute subcutaneous Achilles tendon rupture remains challenging. Whereas the results of conservative and operative treatment are inconsistent, early mobilisation treatment seems to be beneficial. Besides suture repair, operative treatment using adhesives reveals promising results. Our hypothesis was that a gluing technique provides initial stability comparable to sutures.

METHODS

In a biomechanical study, 18 fresh frozen sheep Achilles tendons were used to compare the biomechanical properties of suture repair using PDS® II and Bunnell's technique to tendon gluing using BioGlue® and Tissucol®. Load to failure testing was performed.

RESULTS

Ultimate failure loads of sutures (146.2 ± 30.8 N) are significantly superior to the techniques using BioGlue® (38.4 ± 18.3 N; p <0.0001) or Tissucol® (4.7 ± 2.5 N; p <0.0001). Interestingly, no significant differences in stiffness were found between the application of BioGlue® and PDS® II.

CONCLUSIONS

Suture repair provides significantly superior biomechanical properties compared to the use of both tested adhesives BioGlue® and Tissucol®. Based on the presented data we recommend the use of suture material for open Achilles tendon repair.

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.

[The operative treatment of the degenerative rupture of the anterior tibialis tendon]

AIM

A degenerative tear of the anterior tibial tendon is a rare event compared to other tendons. The purpose of this study was to evaluate the functional results after surgical refixation.

METHOD

In a retrospective study, we report the functional outcome of five consecutive operatively treated patients suffering from a tear close to the insertion site of the anterior tibial tendon. All patients were assessed postoperatively, the AOFAS and Richter scores were obtained and the range of motion in the ankle joint was evaluated.

RESULTS

Preoperatively all patients presented with a significant walking impairment due to a reduced active dorsiflexion, so the decision for surgical refixation was made. In all cases an MRI scan was performed preoperatively. Postoperative immobilisation without weight-bearing was done for six weeks. All patients returned to their former activity level, were satisfied with the postoperative result and had a normal gait in the follow-up examination. The range of motion was equal on both sides, the median AOFAS score was 86 and the median Richter score was 90 out of 100. There were no postoperative complications.

DISCUSSION

Untreated tears of the anterior tibial tendon lead to significant impairment of the ankle joint and deformities of the foot. There is no consensus about the treatment with recommendations for operative and non-operative treatment. Various surgical procedures have been described. The surgical reconstruction of the tendon leads to a restored function of the ankle joint and allows a normal gait and is therefore desirable. Due to the loss of function and the good results after surgical treatment in our study, the non-operative treatment is not advisable.

CONCLUSION

Surgical repair of degenerative tears of the anterior tibial tendon leads to very good functional results and high patient satisfaction.

Quantitative assessment of glenohumeral translation after anterior shoulder dislocation and subsequent arthroscopic bankart repair

BACKGROUND

During the past decade, developments in arthroscopic technology have made arthroscopic repair of labral lesions feasible. However, results with the use of the transglenoid suture technique, or with the use of bioabsorbable tacks, have remained variable in the literature, and the recurrence rates are still inferior to those of open Bankart repair.

HYPOTHESIS

Arthroscopic Bankart repair with suture anchors can re-create translational and rotational range of motion of the intact glenohumeral joint, and the number of preoperative dislocations has an influence on the result.

STUDY DESIGN

Controlled laboratory study.

MATERIALS

Twelve cadaveric shoulders were tested in a robot-assisted shoulder simulator. Anterior and posterior translation and external rotation were measured for intact, dislocated (shoulders were randomly selected to 1 of 3 groups, which were dislocated 1, 3, or 7 times), and repaired conditions at 0 degrees and 90 degrees of glenohumeral elevation.

RESULTS

After shoulder dislocation, a significant increase was found in translation and rotation, confirming the creation of a traumatic shoulder instability model. Further testing of the specimen revealed that translational and rotational ranges of motion were reduced by arthroscopic Bankart repair at both testing positions. External rotation was decreased significantly at 0 degrees and 90 degrees of abduction. No significant differences were found between the 3 dislocation groups.

CONCLUSION

The results demonstrate a sufficient biomechanical performance of arthroscopic Bankart repair using suture anchors in a traumatic anterior shoulder instability model. With the numbers available, no relationship was found between the number of dislocations and the postoperative result concerning translational or rotational motion.

CLINICAL RELEVANCE

Glenohumeral translation and rotation after arthroscopic Bankart repair with use of suture anchors approached near normal values, confirming the clinical success of this technique.