[Surgical treatment of arthrofibrosis of the knee joint]. / Operative Therapie der Arthrofibrose des Kniegelenks.

Arthrofibrosis of the knee joint is a severe complication following trauma and surgical procedures, which often results in long-term impairment of joint function. Early mobilization techniques and anesthesia are still employed without sufficient clarification of the underlying processes. While the early stages of arthrofibrosis can be successfully treated with conservative measures for pain reduction and wound healing, in the late stage tense collagenous scar tissue is frequently present that permanently limits joint mobility. In this stage an improvement of joint mobility has no chance of success without a surgical intervention. In surgical treatment a differentiation should be made between localized (mostly secondary) arthrofibrosis (e.g. cruciate ligament surgery) and generalized arthrofibrosis (in the majority of cases primarily after total knee arthroplasty) and the treatment planned accordingly. Comorbid pathological alterations (transplant position, instability of the total knee endoprosthesis, implant attrition, low-grade infection, patellofemoral instability or maltracking, patella baja) must be taken into consideration in the treatment. A multimodal accompanying treatment including physiotherapy, pain therapy and psychosomatics is necessary to ensure successful treatment.

Quadriceps and hamstring tendon autografts in ACL reconstruction yield comparably good results in a prospective, randomized controlled trial.

INTRODUCTION: Comparable data of functional outcomes of anterior cruciate ligament reconstruction using either hamstring- or quadriceps tendon grafts is controversial. This prospective, randomized controlled trial aims to provide data comparing both grafts regarding the functional outcome. MATERIALS AND METHODS: A two centre trial involving symptomatic patients 18 years of age or older with an anterior cruciate ligament tear was conducted. We randomly assigned 27 patients to quadruple hamstring tendon reconstruction and 24 to quadriceps tendon reconstruction. The patients were evaluated preoperatively, at 3, 6, 12 and 24 months post-surgery. The primary outcome parameter was the side-to-side knee laxity measured with an arthrometer. Secondary outcomes included results in the International Knee Documentation Committee (IKDC) and Lysholm Scores and isokinetic testing of strength in knee extension and flexion. RESULTS: Forty-four patients (86%) completed the 2-year follow-up. There was significantly improved knee stability at all time intervals with no difference between the two study groups. The manual side-to-side displacement improved by 4.7 ± 3.0 mm in patients with hamstring tendon reconstruction and 5.5 ± 2.9 mm in patients with quadriceps tendon reconstruction. In addition, muscle strength and outcome scores (IKDC and Lysholm Score) did not show any differences between the hamstring tendon group and the quadriceps tendon group. Patients in the hamstring tendon group returned to their pre-injury activity level after 95.2 ± 45.5 days while patients in the quadriceps tendon group needed 82.1 ± 45.6 days. CONCLUSION: Quadriceps and hamstring tendon autografts yield comparably good results in primary anterior cruciate ligament reconstruction.

Impact of smoking on the incidence and post-operative complications of total knee arthroplasty: A systematic review and meta-analysis of cohort studies.

Osteoarthritis and rheumatoid arthritis are the most ubiquitous joint disorders which cause tremendous loss of life quality and impose an economic burden on society. At present, the treatment options for these two diseases comprise non-operative and surgical treatments, amongst those total knee arthroplasties (TKA). Various studies have recognized smoking as a significant risk factor for postoperative complications. Therefore, the purpose of this study was to examine the impact of smoking on the incidence and postoperative complications after a total knee arthroplasty by a systematic review and meta-analysis. The research was performed using PUBMED, Cochrane Library and EMBASE, extracting data from thirteen suitable studies and incorporating 2,109,482 patients. Cohort studies evaluating the impact of smoking on TKA with sufficient data were included for the study, and cohort studies without a proper control group and complete data were excluded. A fixed-effects or random-effects model was used to measure the pooled risk ratio (RR) or hazard ratio (HR) with 95% confidence interval (CI). Compared to non-smokers, smokers had a significantly lower incidence of TKA (p<0.01). However, smokers had a higher incidence of total complications (p=0.01), surgical complications (p<0.01), pneumonia (p<0.01) and revision surgery (p=0.01). No significant difference in the risk of blood transfusion (p=0.42), deep vein thrombosis (p=0.31), pulmonary embolism (p=0.34), urinary tract infection (p=0.46) or mortality (p=0.39) was found between smokers and non-smokers. In conclusion, the study indicated that tobacco has two diametrically opposite effects on TKA patients: 1. Tobacco increases the incidence of surgical complications, pneumonia and revision after TKA; 2. It decreases the overall risk of being a candidate for TKA.

Effect of cyclic compression on bone marrow mesenchymal stromal cells in tissue engineered cartilage scaffold.

In this current study, a novel multilayer porous composite scaffold was fabricated with chitosan (CS), silk fibrin (SF) and nano-hydroxyapatite (n-HA). Scanning electron microscope was utilized to detect the characteristics of the composed scaffold. Rat bone marrow stromal cells (rBMSC) were loaded onto the CS/SF/n-HA scaffold and cultured in a bioreactor under an on-off dynamic compression (10% compressive strain, 0.5 Hz, [2 h action + 4 h pause]/cycle, 4 cycles/day). Metabolism of the loaded rBMSC was assessed through CCK-8 test. Qualitative polymerase chain reaction and western blot were applied to assess the chondrogenic differentiation of the seeded cells. Compressive modulus of the cell/scaffold constructs was analyzed. Additionally, a pig model was employed to evaluate the effect of the tissue-engineered cartilage on repairing of cartilage defect. Results showed that the four layers within the scaffold were tightly connected without gaps between porous interfaces of the layers. Scaffold porosity was 92.20% ± 1.30%. The cyclic compression upregulated chondrogenesis markers (Aggrecan, Sox-9, and collagen II). Increased compressive modulus of the cell/scaffold complex was detected after dynamic compression. The pig bone marrow stromal cells/scaffold complex exposed to cyclic compression presented most favorable reparative effect on the mini pig femoral condyle cartilage defects. Our study suggested that the on-off dynamic compression might be a promising approach to fabricate tissue-engineered cartilage in vitro. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1294-1302, 2019.

Management of knee dislocation prior to ligament reconstruction: What is the current evidence? Update of a universal treatment algorithm.

Traumatic knee dislocation is a rare but potentially limb-threatening injury. Thus proper initial diagnosis and treatment up to final ligament reconstruction are extremely important and a precondition to successful outcomes. Reports suggest that evidence-based systematic approaches lead to better results. Because of the complexity of this injury and the inhomogeneity of related literature, there are still various controversies and knowledge gaps regarding decision-making and step-sequencing in the treatment of acute multi-ligament knee injuries and knee dislocations. The use of ankle-brachial index, routine or selective angiography, braces, joint-spanning or dynamic external fixation, and the necessity of initial ligament re-fixation during acute surgery constitutes current topics of a scholarly debate. The aim of this article was to provide a comprehensive literature review bringing light into some important aspects about the initial treatment of knee dislocation (vascular injury, neural injury, immobilization techniques) and finally develop an accurate data-based universal algorithm, enabling attending physicians to become more acquainted with the management of acute knee dislocation.

Influence of hydrodynamic pressure on the proliferation and osteogenic differentiation of bone mesenchymal stromal cells seeded on polyurethane scaffolds.

Hydraulic pressure has recently been introduced as an effective stimulation in the field of tissue engineering. In this study, a polymer scaffold consisting of polyurethane (PU)-based 1, 4-butanediisocyanate was fabricated. A self-designed bioreactor was employed to produce perfusion and hydrodynamic pressure stimulations. The viability, proliferation and osteogenic differentiation of the rat bone mesenchymal stromal cell (rBMSC) growing in the polymer scaffold were investigated after hydrodynamic pressure stimulation. Additionally, the mechanical properties of the cell-laden constructs were also evaluated. Our findings suggested that the perfusion rate (10 mL/min) and low hydrodynamic pressure stimulation (60 mmHg, 0.5 Hz) maintained the viability of rBMSC during 2 weeks cultivation. The cell proliferation was promoted by 60 mmHg stimulation in the first week. The synthesis of alkaline phosphates and osteocalcin was enhanced after 2 weeks stimulation. Meanwhile, the equilibrium modulus of scaffold was increased by 1.85-fold using 60 mmHg hydrodynamic pressure stimulation. Additionally, type I and III procollagen produced by rBMSC was increased 4.92- and 3.02-fold, respectively. However, no encouraging results were detected in 120 mmHg hydrodynamic pressure group. Our study suggests that the 60 mmHg hydrodynamic pressure is a promising approach to enhance the functional properties of the rBMSC-laden PU-based bone scaffold. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3445-3455, 2017.

Effect of single intralesional treatment of surgically induced equine superficial digital flexor tendon core lesions with adipose-derived mesenchymal stromal cells: a controlled experimental trial.

BACKGROUND: Adipose tissue is a promising source of mesenchymal stromal cells (MSCs) for the treatment of tendon disease. The goal of this study was to assess the effect of a single intralesional implantation of adipose tissue-derived mesenchymal stromal cells (AT-MSCs) on artificial lesions in equine superficial digital flexor tendons (SDFTs). METHODS: During this randomized, controlled, blinded experimental study, either autologous cultured AT-MSCs suspended in autologous inactivated serum (AT-MSC-serum) or autologous inactivated serum (serum) were injected intralesionally 2 weeks after surgical creation of centrally located SDFT lesions in both forelimbs of nine horses. Healing was assessed clinically and with ultrasound (standard B-mode and ultrasound tissue characterization) at regular intervals over 24 weeks. After euthanasia of the horses the SDFTs were examined histologically, biochemically and by means of biomechanical testing. RESULTS: AT-MSC implantation did not substantially influence clinical and ultrasonographic parameters. Histology, biochemical and biomechanical characteristics of the repair tissue did not differ significantly between treatment modalities after 24 weeks. Compared with macroscopically normal tendon tissue, the content of the mature collagen crosslink hydroxylysylpyridinoline did not differ after AT-MSC-serum treatment (p = 0.074) while it was significantly lower (p = 0.027) in lesions treated with serum alone. Stress at failure (p = 0.048) and the modulus of elasticity (p = 0.001) were significantly lower after AT-MSC-serum treatment than in normal tendon tissue. CONCLUSIONS: The effect of a single intralesional injection of cultured AT-MSCs suspended in autologous inactivated serum was not superior to treatment of surgically created SDFT lesions with autologous inactivated serum alone in a surgical model of tendinopathy over an observation period of 22 weeks. AT-MSC treatment might have a positive influence on collagen crosslinking of remodelling scar tissue. Controlled long-term studies including naturally occurring tendinopathies are necessary to verify the effects of AT-MSCs on tendon disease.

Influence of biomechanical and biochemical stimulation on the proliferation and differentiation of bone marrow stromal cells seeded on polyurethane scaffolds.

The aim of the present investigation was to compare the effects of cyclic compression, perfusion, dexamethasone (DEX) and bone morphogenetic protein-7 (BMP-7) on the proliferation and differentiation of human bone marrow stromal cells (hBMSCs) in polyurethane scaffolds in a perfusion bioreactor. Polyurethane scaffolds seeded with hBMSCs were cultured under six different conditions, as follows: 10% Cyclic compression at 0.5 and 5 Hz; 10 ml/min perfusion; 100 nM DEX; 100 ng/ml BMP-7; and 1 ml/min perfusion without mechanical and biochemical stimulation (control). On days 7 and 14, samples were tested for the following data: Cell proliferation; mRNA expression of Runx2, COL1A1 and osteocalcin; osteocalcin content; calcium deposition; and the equilibrium modulus of the tissue specimen. The results indicated that BMP-7 and 10 ml/min perfusion promoted cell proliferation, which was inhibited by 5 Hz cyclic compression and DEX. On day 7, the 5 Hz cyclic compression inhibited Runx2 expression, whereas the 0.5 Hz cyclic compression and BMP-7 upregulated the COL1A1 mRNA levels on day 7 and enhanced the osteocalcin expression on day 14. The DEX-treated hBMSCs exhibited downregulated osteocalcin expression. After 14 days, the BMP-7 group exhibited the highest calcium deposition, followed by the 0.5 Hz cyclic compression and the DEX groups. The equilibrium modulus of the engineered constructs significantly increased in the BMP-7, 0.5 Hz cyclic compression and DEX groups. In conclusion, the present results suggest that BMP-7 and perfusion enhance cell proliferation, whereas high frequency cyclic compression inhibits the proliferation and osteogenic differentiation of hBMSCs. Low frequency cyclic compression is more effective than DEX, but less effective compared with BMP-7 on the osteogenic differentiation of hBMSCs seeded on polyurethane scaffolds.

Chondrocyte survival in osteochondral transplant cylinders depends on the harvesting technique.

PURPOSE: In autologous osteochondral transplantation, the edges of the harvested plug are particularly susceptible to mechanical or thermal damage to the chondrocytes. We hypothesised that the applied harvesting device has an impact on chondrocyte vitality. METHODS: Both knees of five blackhead sheep (ten knees) underwent open osteochondral plug harvesting with three different circular harvesting devices (osteoarticular transfer system harvester [OATS; diameter 8 mm; Arthrex, Munich, Germany], diamond cutter [DC; diameter 8.35 mm; Karl Storz, Tuttlingen, Germany] and hollow reamer with cutting crown [HRCC; diameter 7 mm; Dannoritzer, Tuttlingen, Germany]) from distinctly assigned anatomical sites of the knee joint. The rotary cutters (DC and HRCC) were either used with (+) or without cooling (-). Surgical cuts of the cartilage with a scalpel blade were chosen as control method. After cryotomy cutting, chondrocyte vitality was assessed using fluorescence microscopy and a Live/Dead assay. RESULTS: There were distinct patterns of chondrocyte vitality, with reproducible accumulations of dead chondrocytes along the harvesting edge. No statistical difference in chondrocyte survivorship was seen between the OATS technique and the control method, or between the HRCC+ technique and the control method (P > 0.05). The DC+, HRCC- and DC- techniques yielded significantly lower chondrocyte survival rates compared with the control method (P < 0.05). CONCLUSIONS: Chondrocyte survival in osteochondral cylinders depends on the applied harvesting technique. The use of rotary cutters without cooling yielded worst results, while the traditional OATS punch and rotary cutters with cooling achieved comparable rates of chondrocyte vitality.

Biomechanical comparison of fixation techniques for medial collateral ligament anatomical augmented repair.

PURPOSE: Although the majority of medial collateral ligament (MCL) ruptures can be treated conservatively with good results, some injuries require operative treatment. Besides MCL reconstruction, anatomical augmented repair may be considered. This study was to assess biomechanical properties of different fixation techniques regarding elongation and ultimate load to failure. METHODS: MCL anatomical augmented repair was simulated by fixation of porcine superficial digital flexor tendon grafts at porcine tibiae. Ten different fixation techniques were assessed. Fixation of the tendon graft was performed using 4.0-mm cancellous screws and either (1) 13.5-mm spiked polyether ketone (PEEK) washers; (2) 14-mm spiked washers; (3) 14-mm suture washers; (4) 14-mm customized washers; (5-8) combination of washers and No. 2 polyester sutures (FiberWire©); or using (9) single or (10) double 5.5-mm titanium suture anchors with No. 2 polyethylene sutures (Ultrabraid®). Biomechanical analysis included pretensioning of the constructs at 20 N for 30 s following cyclic loading of 250 cycles between 20 and 100 N at 1 Hz for measurement of elongation. Additionally, ultimate failure load and failure mode analysis were performed. RESULTS: Spiked PEEK washers secured with polyester sutures (5) yielded best biomechanical properties at time zero for both, elongation during cyclic loading (2.9 ± 0.7 mm) and ultimate failure load (469.8 ± 64.3 N). CONCLUSIONS: These results suggest that spiked PEEK washers secured with polyester sutures are the most appropriate fixation technique for MCL anatomical augmented repair, thus providing best requirements to allow early knee mobilization and prevent secondary knee laxity.

Current Concepts for Patellar Dislocation.

CONTEXT: Patellar dislocation usually occurs to the lateral side, leading to ruptures of the Medial Patellofemoral Ligament (MPFL) in about 90% of the cases. Even though several prognostic factors are identified for patellofemoral instability after patellar dislocation so far, the appropriate therapy remains a controversial issue. EVIDENCE ACQUISITION: Authors searched the Medline library for studies on both surgical and conservative treatment for patellar dislocation and patellofemoral instability. Additionally, the reference list of each article was searched for additional studies. RESULTS: A thorough analysis of the anatomical risk factors with a particular focus on patella alta, increased Tibial Tuberosity-Trochlear Groove (TT-TG) distance, trochlear dysplasia as well as torsional abnormalities should be performed early after the first dislocation to allow adequate patient counseling. Summarizing the results of all published randomized clinical trials and comparing surgical and conservative treatment after the first-time patellar dislocation until today indicated no significant evident difference for children, adolescents, and adults. Therefore, nonoperative treatment was indicated after a first-time patellar dislocation in the vast majority of patients. CONCLUSIONS: Surgical treatment for patellar dislocation is indicated primarily in case of relevant concomitant injuries such as osteochondral fractures, and secondarily for recurrent dislocations.

Bisphosphonate Use and Risk of Implant Revision after Total Hip/Knee Arthroplasty: A Meta-Analysis of Observational Studies.

OBJECTIVE: Several studies investigated the association between bisphosphonate use and the risk of implant revision after total hip or knee arthroplasty (THA or TKA); However, the findings were inconsistent. We performed this meta-analysis to evaluate the overall relative risk of such an event. METHODS: We searched the PubMed, EMBASE and Cochrane library databases to identify relevant publications on April 22, 2015. To calculate the pooled risk ratios (RRs) with 95% confidential intervals (CIs), a fixed- or random-effects model was applied based on the heterogeneity across studies. RESULTS: Three cohort studies and one case-control study were included in this meta-analysis. Compared with the bisphosphonate nonusers, the patients who used bisphosphonates for a long period of time had a significantly decreased risk of implant revision after THA/TKA (summary adjusted RR = 0.48, 95% CI: 0.38-0.61), and the summary adjusted RRs for the users who underwent THA and those who underwent TKA were 0.47 (95% CI: 0.36-0.61) and 0.45 (95% CI: 0.21-0.95), respectively. CONCLUSIONS: Long-term use of bisphosphonates is correlated with a significantly decreased risk of implant revision after THA/TKA. However, due to limited number of the included studies, the findings of the present study should be treated with caution. More well-designed studies are required to further confirm our findings.

Biomechanical comparison of two surgical techniques for press-fit reconstruction of the posterolateral complex of the knee.

BACKGROUND: To date, various surgical techniques to treat posterolateral knee instability have been described. Recent studies recommended an anatomical and isometric reconstruction of the posterolateral corner addressing the key structures, such as lateral collateral ligament (LCL), popliteus tendon (POP) and popliteofibular ligament (PFL). Two clinical established autologous respective local reconstruction methods of the posterolateral complex were tested for knot-bone cylinder press-fit fixation to assess efficacy of each reconstruction technique in comparison to the intact knee. NULL HYPOTHESIS: The knot-bone cylinder press-fit fixation for both anatomic and isometric reconstruction techniques of the posterolateral complex shows equal biomechanical stability as the intact posterolateral knee structures. STUDY DESIGN: This was a controlled laboratory study. METHODS: Two surgical techniques (Larson: fibula-based semitendinosus autograft for LCL and PFL reconstruction/Kawano: biceps femoris and iliotibial tract autograft for LCL, PFL and POP reconstruction) with press-fit fixation were used for restoration of posterolateral knee stability. Seven cadaveric knees (66 ± 3.4 years) were tested under three conditions: intact knee, sectioned state and reconstructed knee for each surgical technique. Biomechanical stress tests were performed for every state at 30° and 90° knee flexion for anterior-posterior translation (60 N), internal-external and varus-valgus rotation (5 Nm) at 0°, 30° and 90° using a kinemator (Kuka robot). RESULTS: At 30° and 90° knee flexion, no significant differences between the four knee states were registered for anterior-posterior translation loading. Internal-external and varus-valgus rotational loading showed significantly higher instability for the sectioned state than for the intact or reconstructed posterolateral structures (p < 0.05). There were no significant differences between the intact and reconstructed knee states for internal-external rotation, varus-valgus rotation and anterior-posterior translation at any flexion angles (p > 0.05). Comparing both reconstruction techniques, significant higher varus-/valgus stability was registered for the fibula-based Larson technique at 90° knee flexion (p < 0.05). CONCLUSIONS: Both PLC reconstructions showed equal biomechanical stability as the intact posterolateral knee structures when using knot-bone cylinder press-fit fixation. We registered restoration of the rotational and varus-valgus stability with both surgical techniques. The anterior-posterior translational stability was not influenced significantly. The Larson technique showed significant higher varus/valgus stability in 90° flexion. The latter is easier to perform and takes half the preparation time, but needs grafting of the semitendinosus tendon. The Kawano reconstruction technique is an interesting alternative in cases of missing autografts.

A novel implant-free tibial pull-press-fixation for ACL reconstruction.

INTRODUCTION: Extracortical fixation techniques in anterior cruciate ligament reconstruction bear the risk of tunnel enlargement, while close-to-aperture fixations often show lower failure loads. The purpose for this study was to investigate the biomechanical benefits of a novel implant-free combination of an extra-cortical and close-to-aperture fixation. MATERIALS AND METHODS: Quadrupled human cadaveric semitendinosus tendons were fixed to 30 porcine tibiae with either a cannulated interference screw (I), an implant-free post-fixation (S), or a novel pull-press fixation (P). Specimens were cyclically loaded 20 times between 20 and 60 N followed by 500 cycles with 60-200 N, followed by a load-to-failure test with 1 mm/s. RESULTS: The mean elongation of the tendons in the P-group during the 500 cycles between 60 and 200 N was significantly lower (5.69 ± 2.16 mm) compared to 9.20 ± 3.21 mm in S-group and 9.37 ± 3.1 mm in the I-group (p < 0.05). The mean maximum load-to-failure was significantly higher in the P-group (728.2 ± 76.4 N) compared to 476.4 ± 68.8 N in the S-group and 625.9 ± 82.5 N in the I-group (p < 0.05). Stiffness of the constructs in the P-group was significantly higher (121.7 ± 44.9 N/mm) compared to 46.2 ± 17.7 N/mm in the S- and 72.8 ± 29.8 N/mm in the I-group (p < 0.03). CONCLUSIONS: This study indicates superior biomechanical properties of a novel implant-free tibial pull-press fixation to conventional implant-free and close-to-aperture interference screw fixations in terms of cyclic elongation and maximum load-to-failure. LEVEL OF EVIDENCE: Not applicable, basic science study.

Smoking and risk of prosthesis-related complications after total hip arthroplasty: a meta-analysis of cohort studies.

OBJECTIVE: Increasing evidence suggests that smoking may increase the incidence of prosthesis-related complications after total hip arthroplasty (THA). We performed a meta-analysis of cohort studies to quantitatively evaluate the association between smoking and the risk of prosthesis-related complications after THA. METHODS: Relevant articles published before August 15, 2014, were identified by searching the PubMed, EMBASE and Cochrane library databases. Pooled risk ratios (RRs) or weighted mean differences (WMDs) with 95% confidence intervals (CIs) were calculated with either a fixed- or random-effects model. RESULTS: Six cohort studies, involving a total of 8181 participants, were included in the meta-analysis. Compared with the patients who never smoked, smokers had a significantly increased risk of aseptic loosening of prosthesis (summary RR=3.05, 95% CI: 1.42-6.58), deep infection (summary RR=3.71, 95% CI: 1.86-7.41) and all-cause revisions (summary RR=2.58, 95% CI: 1.27-5.22). However, no significant difference in the risk of implant dislocation (summary RR= 1.27, 95% CI: 0.77-2.10) or length of hospital stay (WMD=0.03, 95% CI: -0.65-0.72) was found between smokers and nonsmokers. CONCLUSIONS: Smoking is associated with a significantly increased risk of aseptic loosening of prosthesis, deep infection and all-cause revisions after THA, but smoking is not correlated with a risk of implant dislocation or the length of hospital stay after surgery.

An accuracy evaluation of clinical, arthrometric, and stress-sonographic acute ankle instability examinations.

BACKGROUND: Ankle sprain injuries, often due to lateral ligamentous injury, are the most common sports traumatology conditions. Correct diagnoses require an understanding of the assessment tools with a high degree of diagnostic accuracy. Obviously, there are still no clear consensuses or standard methods to differentiate between a ligament tear and an ankle sprain. In addition to clinical assessments, stress sonography, arthrometer and other methods are often performed simultaneously. These methods are often costly, however, and their accuracy is controversial. The aim of this study was to investigate three different measurement tools that can be used after a lateral ligament lesion of the ankle with injury of the anterior talofibular ligament to determine their diagnostic accuracy. METHODS: Thirty patients were recruited for this study. The mean patient age was 35±14 years. There were 15 patients with a ligamentous rupture and 15 patients with an ankle sprain. We quantified two devices and one clinical assessment by which we calculated the sensitivity and specifity: Stress sonography according to Hoffmann, an arthrometer to investigate the 100N talar drawer and maximum manual testing and the clinical assessment of the anterior drawer test. A high resolution sonography was used as the gold standard. RESULTS: The ultrasound-assisted gadgetry according to Hoffmann, with a 3mm cut-off value, displayed a sensitivity of 0.27 and a specificity of 0.87. Using a 3.95mm cut-off value, the arthrometer displayed a sensitivity of 0.8 and a specificity of 0.4. The clinical investigation sensitivities and specificities were 0.93 and 0.67, respectively. CONCLUSIONS: Different assessment methods for ankle rupture diagnoses are suggested in the literature; however, these methods lack reliable data to set investigation standards. Clinical examination under adequate analgesia seems to remains the most reliable tool to investigate ligamentous ankle lesions. Further clinical studies with higher case numbers are necessary, however, to evaluate these findings and to measure the reliability.

Preliminary results of a new test for rapid diagnosis of septic arthritis with use of leukocyte esterase and glucose reagent strips.

BACKGROUND: Most currently used tools to diagnose septic arthritis are either not readily available or fail to provide real-time results. Reagent strip tests have identified infections in various body fluids. We hypothesized that combined leukocyte esterase and glucose strip tests can aid in diagnosing septic arthritis in native synovial fluid because (1) leukocyte esterase concentrations would be elevated at the infection site because of secretion by recruited neutrophils, and (2) glucose concentrations would be reduced because of bacterial metabolism. METHODS: We prospectively investigated synovial fluid from consecutive patients with an atraumatic joint effusion who underwent arthrocentesis in our emergency department during a one-year period. Leukocyte esterase and glucose strip tests were performed on the synovial fluid. Synovial fluid leukocyte count, crystal analysis, Gram staining, culture, and glucose concentration results were also assessed. RESULTS: Nineteen fluids were classified as septic and 127 as aseptic. Considering septic arthritis to be present when the leukocyte esterase reading was positive (++ or +++) and the glucose reading was negative (-) yielded a sensitivity of 89.5% (95% confidence interval [CI], 66.9% to 98.7%), specificity of 99.2% (95% CI, 95.7% to 99.9%), positive predictive value of 94.4% (95% CI, 72.7% to 99.9%), negative predictive value of 98.4% (95% CI, 94.5% to 99.8%), positive likelihood ratio of 114, and negative likelihood ratio of 0.11. The synovial leukocyte counts and polymorphonuclear cell percentages were consistent with the semiquantitative readings on the leukocyte esterase strip tests, and the glucose concentrations were consistent with the glucose strip test results. CONCLUSIONS: Combined leukocyte esterase and glucose strip tests can be a useful additional tool to help confirm or rule out a diagnosis of septic arthritis.

Conversion of hemi into reverse shoulder arthroplasty: implant design limitations.

PURPOSE: Cranial migration of shoulder hemiarthroplasties due to rotator cuff insufficiency typically requires conversion into a reverse total shoulder arthroplasty. This study was conducted to analyze differences between the height and offset of six implants designed to enable conversion of a hemiarthroplasty into a reverse system. METHODS: Anteroposterior radiographs of 40 shoulders were taken. An image analyzing software was used to simulate the implantation of the hemiprostheses. Then the implant was dissembled, leaving on the stem within the humeral shaft. Finally, the implantation of a reverse system was simulated using the stem in the same position. Values are reported as ∆-height and ∆-offset ± standard deviation. Significance was assumed for P < 0.05. RESULTS: The least decrease in height was determined for Implantcast with 11.6 ± 3.3 mm, followed by DePuy (16 ± 5.7 mm) and the greatest for Tornier with 33 ± 5.3 mm. No significant differences were found among Exactech, Mathys and Zimmer. The largest offset-deviation was calculated for DePuy (-21.7 ± 3.7 mm) and the smallest for Implantcast (-3.3 ± 2.8 mm) and Tornier (1.5 ± 5.7 mm). CONCLUSIONS: Due to the modular stem, the system of Implantcast can be converted in a reverse system with the least changes in height and offset. For the other manufacturers it does not seem possible to convert a hemiprosthesis to a reversed prosthesis without accepting additional tension of the deltoid muscle. Further experimental studies have to analyze the changes in deltoid abduction moments after conversion of a hemi- into a reversed prosthesis.

Near-infrared spectroscopy correlates with established histological scores in a miniature pig model of cartilage regeneration.

Near-Infrared Spectroscopy (NIRS) could be of clinical relevance in modern cartilage regeneration.In a miniature pig model correlation of measurements and histologic scores have never been used before. The data analysis was part of an animal project that investigated the effects of seeding a chondrogenic and osteogenic scaffold with a bone-marrow-derived cell concentrate and reports the histological and mechanical properties. We created 20 osteochondral defects in the femoral condyles of 10 miniature pigs.The defects were left empty (E), filled with the grafted cylinder upside down (U), or with a combined scaffold (S) containing a spongy bone cylinder covered with a collagen membrane. In the fourth group, the same scaffolds were implanted but seeded with a stem cell concentrate (S+BMCC). The animals were euthanized after 3 months, and histologic and spectrometric analyses were performed. NIRS measurements were significantly higher in the central area of the defects of group S+BMCC compared to the central area of the defects of group U. In all groups, a correlation between NIRS and the histologic scores could be demonstrated though on different levels. In the central area, a good NIRS measurement correlates with low (good) histologic scores. In group E and group S, this negative correlation was significant (p=0.01). For the first time, NIRS was successfully used to evaluate osteochondral constructs in a miniature pig model.