10-Year Survival Rates After High Tibial Osteotomy Using Angular Stable Internal Plate Fixation: Case Series With Subgroup Analysis of Outcomes After Combined Autologous Chondrocyte Implantation and High Tibial Osteotomy.

BACKGROUND: Good-to-excellent midterm results after high tibial osteotomy (HTO) to treat medial compartment cartilage defects or osteoarthritis (OA) have been published, but little is known about long-term survival rates in terms of conversion to total knee arthroplasty (TKA) using angular stable internal plate fixation. PURPOSE: To determine TKA-free survival rates and functional and radiological outcomes at 10 years after HTO. A subgroup analysis of patients who underwent combined HTO and autologous cartilage implantation (ACI) was also performed. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Included were 125 patients with a mean follow-up of 9.90 ± 2.25 years; 90 patients underwent HTO for medial OA, and 35 patients underwent ACI and HTO for medial focal cartilage defects. Functional outcome measures included visual analog scale (VAS) for pain, Lysholm, International Knee Documentation Committee (IKDC), and Knee injury and Osteoarthritis Outcome Score (KOOS) subscales and KOOS4 (average of 4 KOOS subscales: Pain, Symptoms, Sport, and Quality of Life). Radiological outcomes included lateral distal femoral angle, medial proximal tibial angle, and joint line convergence angle. RESULTS: Overall, 16 patients required conversion to TKA at a mean 86.75 ± 25.73 months (10-year survival rate, 87.2%). Only 2 patients in the HTO+ACI subgroup required a conversion to TKA (10-year survival rate, 94.3%). The complication rate for all patients was 8.8%. In both the HTO and HTO+ACI subgroups, VAS pain levels decreased and Lysholm scores increased significantly from pre- to postoperatively (P < .001). A higher preoperative Tegner score led to a significantly lower risk for conversion to TKA (P = .001), and a preoperative body mass index of ≥35 was associated with a significantly higher risk (P = .019), as was female sex (P = .046). Radiological parameters remained within physiological ranges. The postoperative joint line conversion angle did correlate with postoperative functional outcome but not with TKA conversion. CONCLUSION: Long-term results of HTO for medial compartment OA or cartilage defects with underlying varus deformity were good to excellent. In particular, patients who underwent HTO+ACI presented excellent long-term survival rates. HTO, therefore, delays or prevents TKA implantation, especially in young, active patients with medial compartment damage.

Viscoelasticity and histology of the human cartilage in healthy and degenerated conditions of the knee.

BACKGROUND: There are many studies on osteoarthritis, but only a few studies deal with human arthrosis, comparing the mechanical properties of healthy and diseased samples. In most of these studies, only isolated areas of the tibia are examined. There is currently only one study investigating the complete mapping of cartilage tissue but not the difference between instantaneous modulus (IM) in healthy and diseased samples. The aim of this study is to investigate the relationship between the biomechanical and histological changes of articular cartilage in the pathogenesis of osteoarthritis. METHODS: The study compared 25 tibiae with medial gonarthrosis and 13 healthy controls. The IM was determined by automated indentation mapping using a Mach-1 V500css testing machine. A grid was projected over the sample and stored so that all measurements could be taken at the same positions (100 ± 29 positions across the tibiae). This grid was then used to perform the thickness measurement using the needle method. Samples were then taken for histological examinations using a hollow milling machine. Then Giemsa and Safranin O staining were performed. In order to determine the degree of arthrosis according to histological criteria, the assessment was made with regard to Osteoarthritis Research Society International (OARSI) and AHO scores. RESULTS: A significant difference (p < 0.05) could be observed in the measured IM between the controls with 3.43 ± 0.36 MPa and the samples with 2.09 ± 0.18 MPa. In addition, there was a significant difference in IM in terms of meniscus-covered and meniscus-uncovered areas. The difference in cartilage thickness between 2.25 ± 0.11 mm controls and 2.0 ± 0.07 mm samples was highly significant with p < 0.001. With regard to the OARSI and AHO scores, the samples differed significantly from the controls. The OARSI and AHO scores showed a significant difference between meniscus-covered and meniscus-uncovered areas. CONCLUSIONS: The controls showed significantly better viscoelastic behavior than the arthrotic samples in the measured IM. The measured biomechanical values showed a direct correlation between histological changes and altered biomechanics in gonarthrosis.

Significant increase of pathogen detection rate by dry arthroscopic biopsies at suspected low-grade infection following total knee arthroplasty: a prospective observational study.

INTRODUCTION: The differentiation between stiff-knee and low-grade periprosthetic joint infection (PJI) is the current diagnostic challenge in total knee (TKA) revision arthroplasty. The aim of this study was to investigate the additional value of dry biopsies, compared to wet biopsies, in patients presenting with knee stiffness following primary TKA. MATERIALS AND METHODS: Single center, prospective observational study. Consecutive patients with joint stiffness of unknown origin following primary TKA were enrolled. Patient assessment followed the diagnostic standard algorithm. During diagnostic arthroscopy, synovial fluid (synovial WBC, PMN%) and five dry biopsies (dry) were collected. Then fluid was infused and another five microbiology (wet) and five histological biopsies gathered, all from identical locations. The primary outcome parameter was the difference between the pathogens in wet and dry biopsies. RESULTS: 71 patients (61% females, 67 ± 10 years) were eligible. Preoperative blood serology mean CRP (0.7 ± 1.5 mg/dl; p = 0.852), WBC (6.6 ± 1.7 G/l; p = 0.056), and synovial fluid mean WBC (1639 ± 2111; p = 0.602), PMN% (38 ± 28; p = 0.738) did not differ between patients with negative, positive wet or dry biopsies. The histology was in 11% positive (p = 0.058). In 32% at least one pathogen was detected, 48% from wet, 44% from dry biopsies. An inhomogeneous distribution was found. Cutibacterium acnes (100%) was solely found in wet, Micrococcus luteus (75%), Staphylococcus capitis (67%), and Micrococcus lylae (100%) were predominantly found in dry biopsies. Additional dry biopsies increased the pathogen detection rate by 49%. CONCLUSION: The addition of dry biopsies to the current standard diagnostic algorithm for PJI increased the pathogen detection rate by 49%.

Single-Bundle Versus Double-Bundle Anterior Cruciate Ligament Reconstruction-5-Year Results.

PURPOSE: To compare anatomic single-bundle (SB) with double-bundle (DB) anterior cruciate ligament reconstruction (ACL-R) and to evaluate the respective clinical outcome results. METHODS: In a prospective randomized study, 64 patients were included and separated into 2 groups. Anatomic SB and DB ACL-Rs were performed with hamstring tendons. Five years after surgery, the follow-up (FU) examination comprised International Knee Documentation Committee (IKDC) 2000, Laxitester (ORTEMA Sport Protection, Markgroeningen, Germany) measurement, and radiograph evaluation. Power calculation was performed to achieve a 95% confidence interval and 80% power on the base of 7-point IKDC subjective difference between the groups. RESULTS: A total of 53 patients (83% FU) were examined at 63.2 ± 4.7 months after surgery: 28 patients in the DB group and 25 patients in the SB group. IKDC subjective (SB: 92.8 ± 6.2, DB: 91.6 ± 7.1; P = .55) and objective scores (grade A SB/DB 20%/25%, B SB/DB 72%/57%, C SB/DB 8%/18%, D SB/DB 4%/0%; P = .45) showed no differences comparing both groups. The Laxitester measurements showed no significant difference in regard to anterior-posterior translation in neutral, internal, and external rotation or to rotation angles (P = .79). No difference was seen between the groups regarding osteoarthritic changes and tunnel widening. CONCLUSIONS: At the 5-year FU, no advantage for either the DB or SB technique in ACL-R can be seen with regard to patient-related and objective outcome measures. LEVEL OF EVIDENCE: Level I, prospective randomized controlled clinical trial.

Carbon-Fibre-Reinforced SiC Composite (C/SiSiC) as an Alternative Material for Endoprosthesis: Fabrication, Mechanical and In-Vitro Biological Properties.

Particle-induced periprosthetic osteolysis and subsequent aseptic implant loosening are a major cause of compromising the long-term results of total joint replacements. To date, no implant has been able to mirror radically the tribological factors (friction/lubrication/wear) of in vivo tribological pairings. Carbon-Fibre Reinforced SiC-Composites (C/SiSiC), a material primarily developed for brake technology, has the opportunity to fulfil this requirement. Until now, the material itself has not been used in medicine. The aim of this investigation was to test the suitability of C/SiSiC ceramics as a new material for bearing couples in endoprosthetics. After the preparation of the composites flexural strength was determined as well as the Young's-modulus and the coefficient of friction. To investigate in vitro biological properties, MG 63 and primary human osteoblasts were cultured on C/SiSiC composites. To review the proliferation, the cytotoxicity standardized tests were used. The cell morphology was observed by light microscopy, ESEM, confocal and 3D-laserscanning microscopy. C/SiSiC possesses a high resistance to wear. Cells exhibited no significant alterations in morphology. Vitality was not impaired by contact with the ceramic composite. There was no higher cytotoxicity to observe. Regarding these results, C/SiSiC ceramics seem to be biologically and mechanically appropriate for orthopaedic applications.

Outcome and complications after treatment of facial fractures at different times in polytrauma patients.

Finding the correct point of time for operative treatment of facial fractures in multiply injured people remains one of the most important challenges in modern emergency medicine. Findings relating to pathophysiological mechanisms after severe trauma argue against the early operative treatment of non-life-threatening injuries. Our retrospective analysis investigated the effects on complications and outcome of different time points for operative treatment of maxillofacial fractures in multiply injured patients. Over a period of 10 years (2003-2012) we could identify 1543 patients, of whom 553 had fractures of the facial skull. 168 of the facial fracture patients were operated on their fractures, 97 at a time later than 72 h. Despite the delayed time of operation, the patients showed fewer complications (21.6% vs 25.4%). This resulted in fewer additional stays in hospital (9.3% vs 11.3%), and also in fewer plate removals (23.7% vs 33.8%). We conclude that delayed operative fracture treatment does not lead to more complications. The optimal time for operative treatment has to be determined individually as the earliest point at which no adverse effects from comorbidities are expected.

3D Powder Printed Bioglass and ß-Tricalcium Phosphate Bone Scaffolds.

The use of both bioglass (BG) and ß tricalcium phosphate (ß-TCP) for bone replacement applications has been studied extensively due to the materials' high biocompatibility and ability to resorb when implanted in the body. 3D printing has been explored as a fast and versatile technique for the fabrication of porous bone scaffolds. This project investigates the effects of using different combinations of a composite BG and ß-TCP powder for 3D printing of porous bone scaffolds. Porous 3D powder printed bone scaffolds of BG, ß-TCP, 50/50 BG/ß-TCP and 70/30 BG/ß-TCP compositions were subject to a variety of characterization and biocompatibility tests. The porosity characteristics, surface roughness, mechanical strength, viability for cell proliferation, material cytotoxicity and in vitro bioactivity were assessed. The results show that the scaffolds can support osteoblast-like MG-63 cells growth both on the surface of and within the scaffold material and do not show alarming cytotoxicity; the porosity and surface characteristics of the scaffolds are appropriate. Of the two tested composite materials, the 70/30 BG/ß-TCP scaffold proved to be superior in terms of biocompatibility and mechanical strength. The mechanical strength of the scaffolds makes them unsuitable for load bearing applications. However, they can be useful for other applications such as bone fillers.

Sporting Activity Is Reduced 11 Years After First-Generation Autologous Chondrocyte Implantation in the Knee Joint.

BACKGROUND: Little is known about long-term sporting activity after periosteal autologous chondrocyte implantation (ACI-P) and its correlation to clinical, morphological, and ultrastructural cartilage characteristics on magnetic resonance imaging (MRI). PURPOSE: To evaluate long-term sporting activity after ACI-P and to correlate with clinical and MRI findings. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients who underwent ACI-P for isolated cartilage defects of the knee joint between 1997 and 2001 were analyzed for sporting ability for 3 different time points: lifetime until the onset of pain, the year before ACI-P, and 11 years (range, 9.0-13.4 years) postoperatively. Sporting activity was assessed and patients' level of activity scaled using standardized questionnaires. MRI scans of the affected knee joint at follow-up were analyzed using the MOCART (magnetic resonance observation of cartilage repair tissue) score and T2 mapping. RESULTS: Seventy of 86 patients (81% follow-up rate) consisting of 25 female and 45 male patients, with a mean age of 33.3 ± 10.2 years at the time of surgery, mean defect size of 6.5 ± 4.0 cm2, and 1.17 treated defects per patient, agreed to participate in the study at a mean 10.9 ± 1.1 years after ACI-P. Fifty-nine patients (69% of total; 84% of follow-up) agreed to MRI, allowing the complete evaluation of 71 transplant sites. Before the onset of symptoms (lifetime), 95.7% of patients played a mean 6.0 sporting activities at a competitive level. In the year before ACI-P, 81.4% of patients played a mean 3.4 sporting activities in 2.4 sessions during 5.4 hours per week at a recreational level. At follow-up, 82.9% of the patients played a mean 3.0 sporting activities in 1.8 sessions during 3.0 hours per week at a recreational level. In contrast to objective factors, 65.6% of the patients felt that their subjective sporting ability had improved or strongly improved after ACI-P, whereas 12.9% felt that their situation had declined or strongly declined, and 21.4% stated that their sporting ability had undergone no change because of surgery. Factors of sporting activity correlated significantly with clinical long-term outcomes. MRI analysis with a mean repair tissue T2 relaxation time of 35.2 milliseconds and mean MOCART score of 44.9 showed no conclusive significant correlation to sporting activity. Level of performance was the only sporting activity factor to show a weak correlation with subgroups of the MOCART score. CONCLUSION: The premorbid level of sporting and recreational activities cannot be achieved 11 years after ACI-P. The MRI results determined at this time point did not conclusively correlate with long-term sporting activity.

"Back on Track": A Mobile App Observational Study Using Apple's ResearchKit Framework.

BACKGROUND: In March 2015, Apple Inc announced ResearchKit, a novel open-source framework intended to help medical researchers to easily create apps for medical studies. With the announcement of this framework, Apple presented 5 apps built in a beta phase based on this framework. OBJECTIVE: The objective of this study was to better understand decision making in patients with acute anterior cruciate ligament (ACL) ruptures. Here, we describe the development of a ResearchKit app for this study. METHODS: A multilanguage observatory study was conducted. At first a suitable research topic, target groups, participating territories, and programming method were carefully identified. The ResearchKit framework was used to program the app. A secure server connection was realized via Secure Sockets Layer. A data storage and security concept separating personal information and study data was proposed. Furthermore, an efficient method to allow multilanguage support and distribute the app in many territories was presented. Ethical implications were considered and taken into account regarding privacy policies. RESULTS: An app study based on ResearchKit was developed without comprehensive iPhone Operating System (iOS) development experience. The Apple App Store is a major distribution channel causing significant download rates (>1.200/y) without active recruitment. Preliminary data analysis showed moderate dropout rates and a good quality of data. A total of 180 participants were currently enrolled with 107 actively participating and producing 424 completed surveys in 9 out of 24 months. CONCLUSIONS: ResearchKit is an easy-to-use framework and powerful tool to create medical studies. Advantages are the modular built, the extensive reach of iOS devices, and the convenient programming environment.

Composite material consisting of microporous ß-TCP ceramic and alginate for delayed release of antibiotics.

OBJECTIVE: The aim of this study was to produce a novel composite of microporous ß-TCP filled with alginate and Vancomycin (VAN) to prolong the release behavior of the antibiotic for up to 28days. MATERIAL AND METHODS: Using the flow chamber developed by the group, porous ceramics in a directional flow were filled with alginates of different composition containing 50mg/mL of antibiotics. After cross-linking the alginate with calcium ions, incubation took place in 10mL double-distilled water for 4weeks at 37°C. At defined times (1, 2, 3, 6, 9, 14, 20 and 28days), the liquid was completely exchanged and analyzed by capillary zone electrophoresis and microtiter trials. For statistical purposes, the mean and standard deviation were calculated and analyzed by ANOVA. RESULTS: The release of VAN from alginate was carried out via an external calcium source over the entire period with concentrations above the minimal inhibitory concentration (MIC). The burst release measured 35.2±1.5%. The release of VAN from alginate with an internal calcium source could only be observed over 14days. The burst release here was 61.9±4.3%. The native alginate's burst release was 54.1±7.8%; that of the sterile alginate 40.5±6.4%. The microtiter experiments revealed efficacy over the entire study period for VAN. The MIC value was determined in the release experiments as well in a range of 0.5-2.0µg/mL against Staphylococcus aureus. STATEMENT OF SIGNIFICANCE: Drug release systems based on ß-TCP and hydrogels are well documented in literature. However, in all described systems the ceramic, as granule or powder, is inserted into a hydrogel. In our work, we do the opposite, a hydrogel which acts as reservoir for antibiotics is placed into a porous biodegradable ceramic. Eventually, this system should be applied as treatment of bone infections. Contrary to the "granule in hydrogel" composites it has the advantage of mechanical stability. Thus, it can take over functions of the bone during the healing process. For a quicker translation from our scientific research into clinical use, only FDA approved materials were used in this work.

Long-term Results of Arthroscopic Arthrolysis for Arthrofibrosis After Anterior Cruciate Ligament Reconstruction.

PURPOSE: The current study was conducted to evaluate the long-term clinical and radiological outcomes after arthroscopic arthrolysis for arthrofibrosis after anterior cruciate ligament reconstruction (ACLR). METHODS: All patients treated with arthrolysis between 1990 and 1998 were included. Indication was arthrofibrosis in at least one knee compartment or a cyclops syndrome limiting range of motion (ROM) by > 5° of extension deficit and 15° of flexion deficit. International Knee Documentation Committee (IKDC) 2000 subjective and objective, Lysholm score, and x-ray evaluation were documented. Statistical analysis and power calculation were performed (P < .05). RESULTS: One hundred forty-one patients (follow-up, 71%) were examined at a mean of 18.7 ± 2.6 years after arthroscopic arthrolysis. Mean IKDC 2000 score was 79.49 ± 14.32. IKDC objective was normal in 0%, nearly normal in 6%, abnormal in 56%, and severely abnormal in 38%. One hundred percent of patients showed more than grade II osteoarthritis. ROM improvement after arthrolysis did not change significantly compared with midterm results (t = 4.5 years). Patients with persisting motion deficits (P = .02) and after medial meniscus resection (P < .001) at time of ACLR showed significantly greater progression of osteoarthritis in comparison with patients without these additional disorders. In case of arthrolysis later than 1 year after ACLR, a more severe osteoarthritis grade (4% vs 20% grade III; P = .038) and a lower jump distance (IKDC: 61% A, 25% B vs 39% A, 41% B; P = .028) were obvious compared with patients who underwent arthrolysis within the first year after ACLR. CONCLUSIONS: Long-term motion improvement can be achieved by arthrolysis. Persistent loss of motion resulted in a higher degree of osteoarthritis in the study population. Early intervention seems advisable as patients with arthrolysis later than 1 year after index surgery reached worse IKDC objective grading. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Complications after surgical management of distal lower leg fractures.

BACKGROUND: Osseous healing of distal lower leg fractures can be prolonged and is often associated with wound healing problems because of the marginal soft - tissue and vascular supply in this area. Postoperative complications are frequent, and according to the literature, open reduction and plate fixation is thought to be associated with higher complication rates. The objective of this study was to evaluate the most common postoperative complications following intramedullary nailing or plate osteosynthesis of distal lower leg injuries with a focus on combined tibio-fibular fractures. The outcomes of patients with and without complications associated the two surgical techniques were compared. METHODS: During a 5-year period, all surgically treated distal tibiofibular fractures were retrospectively collected from the clinical database and were evaluated for the presence of postoperative complications which included compartment syndrome, wound infection, delayed union and non-union, synostosis and rotational malalignment. Postoperative complications were reviewed and correlated with patient risk factors. RESULTS: A total of 199 patients were included in the study, and 75 complications were reported. The majority of complications were associated with closed fracture types treated with intramedullary nailing, delayed union being the most frequent. For open fractures, surgical treatment with plate fixation had a complication rate of 12% compared with 25% after intramedullary nailing. DISCUSSION: In general, distal lower leg fractures are associated with a high risk of postoperative complications. Distal diaphyseal tibial fractures that have been treated with intramedullary nailing devices have a higher risk of delayed union or non - union. CONCLUSION: Plate fixation in distal metaphyseal fractures has a higher risk of problems related to wound healing and postoperative wound infections.

Sustained release of rhBMP-2 from microporous tricalciumphosphate using hydrogels as a carrier.

BACKGROUND: Tissue engineering and bone substitutes are subjects of intensive ongoing research. If the healing of bone fractures is delayed, osteoinductive materials that induce mesenchymal stem cells (MSCs) to form bone are necessary. The use of Bone Morphogenetic Protein - 2 is a common means to enhance effectiveness and accelerate the healing process. A delivery system that maintains and releases BMP biological activity in controlled fashion at the surgical site while preventing systemic diffusion (and thereby the risk of undesirable effects by controlling the amount of protein implanted) is essential. In this study, we aimed to test a cylindrical TCP-scaffold (porosity ~ 40 %, mean pore size 5 µm, high interconnectivity) in comparison to BMP-2. Recombinant human BMP-2 was dissolved in different hydrogels as a carrier, namely gelatin and alginate cross-linked with CaCl2-solution, or a solution of GDL and CaCO3. FITC-labeled Protein A was used as a model substance for rhBMP-2 in the pre-trials. For loading, the samples were put in a flow chamber and sealed with silicone rings. Using a directional vacuum, the samples were loaded with the alginate-BMP-2-mixture and the loading success monitored by observing changes in a fluorescent dye (FITC labeled Protein A) under a fluorescence microscope. A fluorescence reader and ELISA were employed to measure the release. Efficacy was determined in cell culture experiments (MG63 cells) via Live-Dead-Assay, FACS, WST-1-Assay, pNPP alkaline phosphatase assay and confocal microscopy. For statistical analysis, we calculated the mean and standard deviation and carried out an analysis of variance. RESULTS: Directional vacuum makes it possible to load nearly 100 % of the interconnected micropores with alginate mixed with rhBMP-2. Using alginate hardened with CaCl2 as a carrier, BMP-2's release can be decelerated significantly longer than with other hydrogels - eg, for over 28 days. The effects on osteoblast-like cells were an increase of the growth rate and expression of alkaline phosphatase while triggering no toxic effect. CONCLUSION: The rhBMP-2-loaded microporous TCP scaffolds possess proliferative and osteoinductive potential. Alginate helps to lower the local growth factor dose below the cytotoxic limit, and allows the release period to be lengthened by at least 28 days.

Single-Bundle Versus Double-Bundle Anterior Cruciate Ligament Reconstruction: A Comparative 2-Year Follow-up.

PURPOSE: To compare anatomic single-bundle (SB) versus double-bundle (DB) anterior cruciate ligament (ACL) reconstruction and to determine possible differences in clinical outcomes. METHODS: In this prospective randomized study, 64 patients were divided into 2 equal groups. Anatomic SB and DB ACL reconstructions were performed using hamstring tendons. A follow-up examination 2 years after surgery comprised International Knee Documentation Committee (IKDC) 2000 assessment, Laxitester (ORTEMA Sport Protection, Markgröningen, Germany) measurement of anteroposterior translation regarding rotational stability, and radiographic evaluation. Statistical analysis and power calculation were performed (P < .05). RESULTS: We examined 62 patients at a mean of 26 months (range, 23.3 to 32.7 months) after surgery. IKDC subjective and objective scores showed no significant differences when both groups were compared. The Laxitester measurements showed no significant differences regarding anteroposterior translation in the neutral position, internal rotation, and external rotation. However, there was a significant improvement in rotational laxity in external rotation in the DB group (P = .02). No differences were seen between the groups regarding osteoarthritic changes and tunnel widening. CONCLUSIONS: There were no differences in IKDC subjective and objective scores between patients who underwent anatomic SB ACL reconstruction and those who underwent anatomic DB ACL reconstruction. LEVEL OF EVIDENCE: Level I, prospective, randomized controlled clinical trial.

Novel Method for Loading Microporous Ceramics Bone Grafts by Using a Directional Flow.

The aim of this study was the development of a process for filling the pores of a ß-tricalcium phosphate ceramic with interconnected porosity with an alginate hydrogel. For filling of the ceramics, solutions of alginate hydrogel precursors with suitable viscosity were chosen as determined by rheometry. For loading of the porous ceramics with the gel the samples were placed at the flow chamber and sealed with silicone seals. By using a vacuum induced directional flow, the samples were loaded with alginate solutions. The loading success was controlled by ESEM and fluorescence imaging using a fluorescent dye (FITC) for staining of the gel. After loading of the pores, the alginate is transformed into a hydrogel through crosslinking with CaCl2 solution. The biocompatibility of the obtained composite material was tested with a live dead cell staining by using MG-63 Cells. The loading procedure via vacuum assisted directional flow allowed complete filling of the pores of the ceramics within a few minutes (10 ± 3 min) while loading through simple immersion into the polymer solution or through a conventional vacuum method only gave incomplete filling.

ß-Tricalcium phosphate for bone replacement: stability and integration in sheep.

Implants of microporous ß-tricalcium phosphate (ß-TCP) were developed for primarily stable supply of bone defects. A consistent stability over the healing period should be retained in sheep. ß-TCP cylindrical shaped implants, with 7 mm diameter, 25 mm length, medium pore diameter 5 µm and 40% porosity were developed. Fresh bone defects of 21 sheep in the medial femur condyle were filled with the implants. At time zero, after 6, 12 and 24 weeks the knees of each 7 animals were studied. Specimens were investigated radiologically, followed by biomechanical and histological analysis. Radiological analysis showed progressive resorption. 6 weeks after surgery results of the indentation test were slightly lower, after 12 and 24 weeks higher than on the healthy opposite knee. At 6 weeks a phagocyte reaction overbalanced. After 12 weeks bone regeneration around the implant was seen. After 24 weeks a highly advanced resorption of TCP implant was realized. The trabecular structure of the new bone increased after 24 weeks. Using microporous ß-TCP implants continuous stable filling of bone defects can be reached in sheep. Microporous ß-TCP implants are resorbed and replaced by bone.

Sports activity following total knee arthroplasty in patients older than 60 years.

In a retrospective study with a population over 65 years, sports activity was conducted 6 years after cruciate retaining (CR) total condylar knee arthroplasty (TKA) with rotating platform (RP). Eighty-one Patients (71.8±5.4years) were examined at follow-up 6.4±0.9 years postoperative. Sport was practiced 5.3 hours every week in mean. Patients were active in sports 3.5times per week. Twenty-five percent performed high impact sports, 47% medium impact sports and 52% low impact sports at follow-up. In KOOS sports 60±28 was reached, in WOMAC 12.1±15.1. It can be concluded that in this population 50% of patients were active in medium and low impact sport 6 years after surgery. However, a quarter of patients were also active in high impact sports.

Novel endoscopic sacroiliac screw removal technique: reduction of intraoperative radiation exposure.

OBJECTIVE: We report in the following on our technique of endoscopic sacroiliacal screw removal as a new extra-articular endoscopic method in soft tissue surgery, aimed at the reduction of radiation exposure for both the patient and the surgical teams. Patients who underwent endoscopic implant removal from the dorsal pelvic ring (Group A) were retrospectively compared with a control group, in which the screws were removed via the conventional approach (Group B). The parameters of interest were the extent of x-ray exposure in seconds and surgical duration in minutes as well as approach related peri- and postoperative complications. RESULTS: 34 screws were removed endoscopically from 28 patients in group A and 35 screws from 29 patients in group B. The mean skin-to-skin time in group A was 36.1 (15-111) min and 32.7 (12-114) min in group B. The difference was not statistically significant (p > 0.05). The average radiation time in group A was 5.7 ± 3.2 s (range, 0-101 s), while in group B the radiation time was significantly longer (52.6 ± 23 s (range, 0-239 s); p = 0.005). CONCLUSIONS: Endoscopic screw removal from the posterior pelvic ring reduces the intraoperative radiation time whereas the skin-to-skin times do not differ from the conventional procedure. LEVEL OF EVIDENCE: Case-control study, Level III.

Rotational laxity and collateral ligament laxity following total knee arthroplasty with rotating platform.

PURPOSE: The aim of this study was to evaluate laxity in knees with pre-operative (preop) valgus alignment compared to knees with pre-operative varus alignment after total knee arthroplasty (TKA). METHODS: This was a retrospective study including 81 patients, with six years follow-up, for pre-operative valgus- or varus alignment of the leg. All patients had been supplied with the same cruciate retaining (CR) TKA with rotating platform. Clinical findings were assessed by KSS, OKS and IKDC 2000 score. Rotational knee laxity was evaluated by a validated instrument (Laxitester®) with 2 Nm torque in 30° flexion. Collateral ligament laxity was tested manually in 30° flexion with a bending moment of approximately 5 Nm. Biomechanical results were compared to the contralateral side. RESULTS: Thirty-one patients had a preop valgus alignment of 8.96° and 50 patients a varus leg axis of 4.99° in the mean. In the preop valgus knees rotational analysis showed an increased laxity of 10.7° compared to preop varus knees (p = 0.001). There was no significant difference in medial (valgus 2.6 mm, varus 2.5 mm) and lateral (valgus 2.8 mm, varus 2.7 mm) laxity. KSS and OKS showed no significant differences in the follow-up results. In the IKDC 2000 objective score 50 % of the preop varus knees and 25.8 % of the preop valgus knees were classified as nearly normal. The difference in the IKDC objective was highly significant (p < 0.001). CONCLUSION: Preop valgus knees show a significantly increased rotational laxity but no increased collateral ligament laxity compared to pre-operative varus knees six years after TKA with rotating platform. There is a significant difference in IKDC objective.

Proximal humeral fracture treatment in adults.

Most proximal humeral fractures affect elderly patients and can be treated nonoperatively with good functional outcomes.The treatment of displaced three and four-part fractures remains controversial and depends on a variety of underlying factors related to the patient (e.g., comorbidity, functional demand), the fracture (e.g., osteoporosis), and the surgeon (e.g., experience).Throughout the literature, open reduction and locking plate osteosynthesis is associated with considerable complication rates, particularly in the presence of osteoporosis.Low local bone mineral density, humeral head ischemia, residual varus displacement, insufficient restoration of the medial column, and nonanatomic reduction promote failure of fixation and impair functional outcome.The outcome of hemiarthroplasty is closely related to tuberosity healing in an anatomic position to enable the restoration of rotator cuff function. Reverse shoulder arthroplasty may provide satisfactory shoulder function in geriatric patients with preexisting rotator cuff dysfunction or after the failure of first-line treatment.