Abstract Validity and reliability as scientific quality criteria have to be considered when using optical motion capture (OMC) for research purposes. Literature and standards recommend individual ...laboratory setup evaluation. However, system characteristics such as trueness, precision and uncertainty are often not addressed in scientific reports on 3D human movement analysis. One reason may be the lack of simple and practical methods for evaluating accuracy parameters of OMC. A protocol was developed for investigating the accuracy of an OMC system (Vicon®, volume 5.5×1.2×2.0 m3 ) with standard laboratory equipment and by means of trueness and uncertainty of marker distances. The study investigated the effects of number of cameras (6, 8 and 10), measurement height (foot, knee and hip) and movement condition (static and dynamic) on accuracy. Number of cameras , height and movement condition affected system accuracy significantly. For lower body assessment during level walking, the most favorable setting (10 cameras, foot region) revealed mean trueness and uncertainty to be −0.08 mm and 0.33 mm, respectively. Dynamic accuracy cannot be predicted based on static error assessments. Dynamic procedures have to be used instead. The significant influence of the number of cameras and the measurement location suggests that instrumental errors should be evaluated in a laboratory- and task-specific manner. The use of standard laboratory equipment makes the proposed procedure widely applicable and it supports the setup process of OCM by simple functional error assessment. Careful system configuration and thorough measurement process control are needed to produce high-quality data.
The etiology of hallux rigidus remains a controversial issue in foot and ankle surgery, i.e., the relationship between metatarsus primus elevatus (MPE) and hallux rigidus. The purpose of this study ...was to evaluate several radiographic parameters including first metatarsal elevation in patients with hallux rigidus compared to a matched control group. A retrospective case control study was performed including 50 feet, 25 feet with and 25 feet without hallux rigidus. In the patients with hallux rigidus, the first metatarsal was more elevated than in the control group (8.3 ± 1.7 mm vs 3.0 ± 2.0 mm, p < .001) and in 60% of patients with hallux rigidus MPE was diagnosed, compared to zero patients in the control group (p < .001). The lateral 1 to 2 intermetatarsal angle was higher in patients with hallux rigidus (3.6 ± 2.5 vs -0.7 ± 2.8; p < .001). The first metatarsal declination angle was not different between the 2 groups. Intraclass correlation coefficient between 2 observers for measuring the first metatarsal elevation was 0.929 (p < .001). In the current study, increased elevation of the first metatarsal, a higher incidence of MPE and increased lateral 1 to 2 intermetatarsal angle were found in patients with hallux rigidus compared to the control group. These findings support the theory of an association between MPE and hallux rigidus. Further high reliability of first metatarsal elevation measurement was found in our study.
Background:
The treatment of displaced intra-articular calcaneal fractures remains a challenge and the optimal approach is still controversial. The main reason to avoid the extended lateral approach ...is the high complication rate due to wound healing problems. We report on 16 years of experience with a standardized limited open reduction and internal fixation technique.
Methods:
Between 2001 and 2017, we prospectively followed 240 consecutive patients operatively treated for a displaced intra-articular calcaneal fracture. Patients with open, multiple, bilateral, extra-articular, and Sanders IV fractures and those lost to follow-up were excluded. A lateral subtalar approach was used, with a cast for 8 weeks and full weightbearing allowed after 12 weeks. Follow-up examinations were scheduled until 24 months. Subjective and clinical assessment included gait abnormality, subtalar and ankle range of motion, and stability and alignment. The American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score was calculated. Alignment was analyzed on standard radiographs. In total, 131 patients were excluded. The remaining 109 patients were followed for a minimum of 24 months (34.4 ± 14.2 range, 24-102 months).
Results:
The mean AOFAS score was 87 ± 13 (range, 32-100). “Excellent” and “good” results, as well as hindfoot motion with “normal/mild” and “moderate” restrictions, were seen in 80% of patients. Early reoperations were performed for insufficient reduction (2 patients), delayed wound healing (debridement, 3 patients), and hematoma (1 patient). Late revisions were arthrodesis (3 patients), medializing calcaneal osteotomy (1 patient), and implant removal (53 patients; 49%).
Conclusion:
The presented approach has remained unmodified for 16 years and resulted in consistently good functional results. The main disadvantage was the high rate of heel screw removal.
Level of Evidence:
Level IV, retrospective case series.
Background:
Acute traumatic rupture of the Achilles tendon can be treated operatively or nonoperatively. Throughout the literature, there is no consensus regarding the optimal treatment protocol.
...Purpose:
To report on 17 years of experience with treating this injury with a standardized nonoperative treatment protocol.
Study Design:
Case Series; Level of evidence, 4.
Methods:
The treatment protocol was based on a combination of an equinus cast and rehabilitation boot, which promoted immediate full weightbearing and early functional rehabilitation. A total of 171 patients were consecutively treated and prospectively followed from 1996 to 2013. Assessed were subjective parameters such as pain, loss of strength, return to previous activity level, meteosensitivity, and general satisfaction with the treatment outcome. Clinical assessment included testing of plantar flexion strength and endurance, calf circumference, and tendon length. Subjective and clinical parameters were then used to calculate a modified Thermann score. The correlation between tendon lengthening and function was calculated using the Pearson correlation coefficient.
Results:
A total of 114 patients were followed for a minimum of 12 months (mean, 27 ± 20 months; range, 12-88 months). The mean Thermann score was 82 ± 13 (range, 41-100), and subjective satisfaction was rated “very good” and “good” in 90%. An inverse correlation was found between tendon length and muscle strength (R = −0.3). There were 11 reruptures (8 with and 3 without an adequate trauma). General complications were 5 deep venous thromboses, 1 complex regional pain syndrome, and minor problems such as transient heel pain (n = 3), heel numbness (n = 1), and cast-associated skin abrasions (n = 4).
Conclusion:
Seventeen years of experience with a nonoperative treatment protocol for acute rupture of the Achilles tendon confirmed good functional outcome and patient satisfaction. Reruptures mostly occurred with new traumatic events in the vulnerable phase from 6 to 12 weeks after the initial injury. Muscle strength correlated to tendon length, making its assessment a crucial follow-up parameter. The protective equinus cast and boot can protect against excessive tendon lengthening during the healing process.
The exponential growth of computing power in the last two decades opens up entirely new options for numerical simulations of the Electric Arc Furnace (EAF). Simulations can be used to analyze ...physical phenomena resisting direct observation or operational measurement even to this very day. This paper gives an overview of the state‐of‐the‐art of the Computational Fluid Dynamics (CFD) simulation on the EAF as well as an outlook on future fields of application, while being well aware that by far not all phenomena and literature can be used. The paper makes no claim to exhaustiveness, especially since three subjects of simulation technology have to be excluded: Process models for furnace controlling, stress calculations, electromagnetic simulations. Thus, the focus is on the fluid‐ and thermo‐dynamic furnace processes and on fundamental methods that can be applied to examine these processes. The basic EAF functionalities and selected fluid‐dynamic simulations are presented, for example, on multiphase flow, thermal loading of refractory lining and wall panels, chemical reactions and post‐combustion, oxygen injection technology, and bottom tapping.
An overview of the state‐of‐the‐art of the Computational Fluid Dynamics (CFD) simulation on the Electric Arc Furnace (EAF) is given. The focus is on fluid‐ and thermo‐dynamic processes and numerical models developed to investigate these processes. EAF functionalities and simulation results are discussed, for example, multiphase flow, thermal loading of refractory or panel, injection technology, bottom tapping, post‐combustion. An outlook on future fields of applications is also given.
Background
Isolated lateral malleolar fractures usually result from a supination-external rotation (SER) injury and may include a deltoid ligament rupture. The necessity of operative treatment is ...based on the recognition of a relevant medial soft-tissue disruption. Currently used tests to assess ankle stability include manual stress radiographs and gravity stress radiographs, but seem to overestimate the need for fracture fixation.
Methods
We investigated the use of weightbearing radiographs to distinguish stable and unstable isolated lateral malleolar fractures induced by the SER mechanism in 57 patients. Patients with stable fractures (SER type II according to the Lauge-Hansen classification) were treated non-operatively with varying external support. Forty-seven patients were evaluated by questionnaire and AOFAS ankle-hindfoot score. Follow-up was 18–120 months (mean 62).
Results
Fifty-one of fifty-seven (90%) patients were found to have stable fractures (SER type II) and were treated non-operatively. The AOFAS score was 96.1 points on average (range 85–100) at latest follow-up. Four patients reported minor complaints. A “moderate” correlation of risk factors (i.e. smoking) to delayed bone healing was found while the correlation of varying external support (i.e. bandage, cast) to the AOFAS score and delayed bone healing was “poor”.
Conclusion
The use of weightbearing radiographs is an easy, pain-free, safe and reliable method to exclude the need for operative treatment, with excellent clinical outcome in the majority of the patients seen at latest follow-up. The delay of 3–10 days until the decision about surgical treatment is well accepted by the patients.
Background:
A fixed cavovarus foot deformity can be associated with anteromedial ankle arthrosis due to elevated medial joint contact stresses. Supramalleolar valgus osteotomies (SMOT) and ...lateralizing calcaneal osteotomies (LCOT) are commonly used to treat symptoms by redistributing joint contact forces. In a cavovarus model, the effects of SMOT and LCOT on the lateralization of the center of force (COF) and reduction of the peak pressure in the ankle joint were compared.
Methods:
A previously published cavovarus model with fixed hindfoot varus was simulated in 10 cadaver specimens. Closing wedge supramalleolar valgus osteotomies 3 cm above the ankle joint level (6 and 11 degrees) and lateral sliding calcaneal osteotomies (5 and 10 mm displacement) were analyzed at 300 N axial static load (half body weight). The COF migration and peak pressure decrease in the ankle were recorded using high-resolution TekScan pressure sensors.
Results:
A significant lateral COF shift was observed for each osteotomy: 2.1 mm for the 6 degrees (P = .014) and 2.3 mm for the 11 degrees SMOT (P = .010). The 5 mm LCOT led to a lateral shift of 2.0 mm (P = .042) and the 10 mm LCOT to a shift of 3.0 mm (P = .006). Comparing the different osteotomies among themselves no significant differences were recorded. No significant anteroposterior COF shift was seen. A significant peak pressure reduction was recorded for each osteotomy: The SMOT led to a reduction of 29% (P = .033) for the 6 degrees and 47% (P = .003) for the 11 degrees osteotomy, and the LCOT to a reduction of 41% (P = .003) for the 5 mm and 49% (P = .002) for the 10 mm osteotomy. Similar to the COF lateralization no significant differences between the osteotomies were seen.
Conclusion:
LCOT and SMOT significantly reduced anteromedial ankle joint contact stresses in this cavovarus model. The unloading effects of both osteotomies were equivalent. More correction did not lead to significantly more lateralization of the COF or more reduction of peak pressure but a trend was seen.
Clinical Relevance:
In patients with fixed cavovarus feet, both SMOT and LCOT provided equally good redistribution of elevated ankle joint contact forces. Increasing the amount of displacement did not seem to equally improve the joint pressures. The site of osteotomy could therefore be chosen on the basis of surgeon’s preference, simplicity, or local factors in case of more complex reconstructions.
Major modifications in the design and techniques of total ankle replacement have challenged the perception that ankle arthrodesis is the treatment of choice for end-stage ankle arthritis. High ...complication and revision rates have been reported after both procedures.
We performed radiographic evaluations at a mean of thirty-nine months following 114 total ankle replacements done with use of commonly used implants and at a mean of thirty-seven months following forty-seven ankle arthrodeses. The mean age was sixty-four years for the patients (fifty-one female and sixty-three male) who underwent total ankle replacement and fifty-nine years in the patients (fifteen female and thirty-two male) who underwent ankle arthrodesis. The impact of complications was analyzed with use of the Ankle Osteoarthritis Scale (AOS), a validated outcome instrument.
Both groups had significant improvement in the mean AOS score (p < 0.001). There was no significant difference in the mean improvement between the two groups (p = 0.96). The complication rate was 54% following total ankle replacement and 26% following ankle arthrodesis, which was a significant difference (p = 0.003). The impact of major complications on the AOS outcome score was significant in both the total ankle replacement group (p = 0.031) and the ankle arthrodesis group (p = 0.02).
At the time of follow-up, at a minimum of two years postoperatively, the outcomes of total ankle replacement and ankle arthrodesis, with regard to pain relief and function, were comparable. While the rate of complications was significantly higher following total ankle replacement, the impact of complications on outcome was clinically relevant in both groups.
Taking into account numerous individual criteria, the correct indication substantially influences the outcome of patients with end-stage ankle arthritis treated by ankle arthrodesis or total ankle ...replacement. The purpose of this report is to assist the foot and ankle surgeon or orthopedic surgeon involved in choosing ankle arthrodesis or total ankle replacement in decision-making. Balancing the criteria that are discussed in consideration of the recent relevant literature and evidence available, the surgeon is directed to the correct individual decision.
Rhabdomyolysis is a potentially fatal condition that can be triggered by a variety of inciting events, including excessive muscular exertion.
The purpose of this study was to investigate the causes ...of creatine kinase elevation (CK≥1000U/L) to determine what percentage result from exRML, the etiology, and kinetics of CK levels, as well as the complications of exRML and comorbidities that may predispose an individual to this condition.
We performed a cross-sectional analysis of the emergency department database for patients with CK≥1000U/L between 2012 and 2017. In total, there were 1957 cases of rhabdomyolysis diagnosed based on laboratory data and documentation. Trauma was the most common cause for rhabdomyolysis (n = 726/1957; 37.1%, respectively).
ExRML was identified in 2.1% (n = 42/1957) of the total cases. Patients with ExRML were significantly younger (30.1 ± 10.6 years) with a significantly higher maximal level of CK compared to the non-exertional causes of rhabdomyolysis, (CK = 16,884.4 ± 41,645.6U/L; both p < 0.005). The far majority of cases were sport or exercise related (n = 35/42; 83.3%), with strength training at the gym making up the largest group of athletes (n = 16/42; 38.1%). The main complication amongst the ExRML group was acute kidney insufficiency, which was observed in 42.9% of patients. The CK levels of the patients in the ExRML cohort steadily decreased after initiation of aggressive hydration.
ExRML may be more prevalent than the current literature predicts, which is important to recognize as it has the potential to cause kidney failure, irregular heart rhythm, and death. Therefore, physicians and active individuals should be sensitized to the signs and symptoms that may lead to earlier recognition and proper treatment in exercising individuals.
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