Defining reference values for the normal tibiofibular syndesmosis in adults using weight-bearing CT.

AIMS: Cone beam CT allows cross-sectional imaging of the tibiofibular syndesmosis while the patient bears weight. This may facilitate more accurate and reliable investigation of injuries to, and reconstruction of, the syndesmosis but normal ranges of measurements are required first. The purpose of this study was to establish: 1) the normal reference measurements of the syndesmosis; 2) if side-to-side variations exist in syndesmotic anatomy; 3) if age affects syndesmotic anatomy; and 4) if the syndesmotic anatomy differs between male and female patients in weight-bearing cone beam CT views. PATIENTS AND METHODS: A retrospective analysis was undertaken of 50 male and 50 female patients (200 feet) aged 18 years or more, who underwent bilateral, simultaneous imaging of their lower legs while standing in an upright, weight-bearing position in a pedCAT machine between June 2013 and July 2017. At the time of imaging, the mean age of male patients was 47.1 years (18 to 72) and the mean age of female patients was 57.8 years (18 to 83). We employed a previously described technique to obtain six lengths and one angle, as well as calculating three further measurements, to provide information on the relationship between the fibula and tibia with respect to translation and rotation. RESULTS: The upper limit of lateral translation in un-injured patients was 5.27 mm, so values higher than this may be indicative of syndesmotic injury. Anteroposterior translation lay within the ranges 0.31 mm to 2.59 mm, and -1.48 mm to 3.44 mm, respectively. There was no difference between right and left legs. Increasing age was associated with a reduction in lateral translation. The fibulae of men were significantly more laterally translated but data were inconsistent for rotation and anteroposterior translation. CONCLUSION: We have established normal ranges for measurements in cross-sectional syndesmotic anatomy during weight-bearing and also established that no differences exist between right and left legs in patients without syndesmotic injury. Age and gender do, however, affect the anatomy of the syndesmosis, which should be taken into account at time of assessment. Cite this article: Bone Joint J 2019;101-B:348-352.

Prevalence of isolated gastrocnemius tightness in patients with foot and ankle pathology: a population-based study.

Aims: Gastrocnemius tightness predisposes to musculoskeletal pathology and may require surgical treatment. However, it is not clear what proportion of patients with foot and ankle pathology have clinically significant gastrocnemius tightness. The aim of this study was to compare the prevalence and degree of gastrocnemius tightness in a control group of patients with a group of patients with foot and ankle pathology. Patients and Methods: This prospective, case-matched, observational study compared gastrocnemius tightness, as assessed by the lunge test, in a control group and a group with foot and ankle pathology. Gastrocnemius tightness was calculated as the difference in dorsiflexion of the ankle with the knee extended and flexed. Results: A total of 291 controls were paired with 97 patients with foot and ankle pathology (FAP). The mean gastrocnemius tightness was 6.0° (sd 3.5) in controls and 8.0° (sd 5.7) in the FAP group (p < 0.001). Subgroup analysis showed a mean gastrocnemius tightness of 10.3° (sd 6.0) in patients with forefoot pathology versus 6.9° (sd 5.3) in patients with other pathology (p = 0.008). A total of 12 patients (37.5%) with forefoot pathology had gastrocnemius tightness of > two standard deviations of the control group (> 13°). Conclusion: Gastrocnemius tightness of > 13° may be considered abnormal. Most patients with foot and ankle pathology do not have abnormal degrees of gastrocnemius tightness compared with controls, but it is present in over a third of patients with forefoot pathology. Cite this article: Bone Joint J 2018;100-B:945-52.

Can a urine dipstick test be used to assess smoking status in patients undergoing planned orthopaedic surgery? a prospective cohort study.

AIMS: Smoking is associated with post-operative complications but smokers often under-report the amount they smoke. Our objective was to determine whether a urine dipstick test could be used as a substitute for quantitative cotinine assays to determine smoking status in patients. PATIENTS AND METHODS: Between September 2013 and July 2014 we conducted a prospective cohort study in which 127 consecutive patients undergoing a planned foot and ankle arthrodesis or osteotomy were included. Patients self-reported their smoking status and were classified as: 'never smoked' (61 patients), 'ex-smoker' (46 patients), or 'current smoker' (20 patients). Urine samples were analysed with cotinine assays and cotinine dipstick tests. RESULTS: There was a high degree of concordance between dipstick and assay results (Kappa coefficient = 0.842, p < 0.001). Compared with the quantitative assay, the dipstick had a sensitivity of 88.9% and a specificity of 97.3%. Patients claiming to have stopped smoking just before surgery had the highest rate of disagreement between reported smoking status and urine testing. CONCLUSION: Urine cotinine dipstick testing is cheap, fast, reliable, and easy to use. It may be used in place of a quantitative assay as a screening tool for detecting patients who may be smoking. A positive test may be used as a trigger for further assessment and counselling. Cite this article: Bone Joint J 2016;98-B:1418-24.

Autologous chondrocyte implantation. Culture in a TGF-beta-containing medium enhances the re-expression of a chondrocytic phenotype in passaged human chondrocytes in pellet culture.

An increasing number of patients are treated by autologous chondrocyte implantation (ACI). This study tests the hypothesis that culture within a defined chondrogenic medium containing TGF-beta enhances the re-expression of a chondrocytic phenotype and the subsequent production of cartilaginous extracellular matrix by human chondrocytes used in ACI. Chondrocytes surplus to clinical requirements for ACI from 24 patients were pelleted and cultured in either DMEM (Dulbecco's modified eagles medium)/ITS+Premix/TGF-beta1 or DMEM/10%FCS (fetal calf serum) and were subsequently analysed biochemically and morphologically. Pellets cultured in DMEM/ITS+/TGF-beta1 stained positively for type-II collagen, while those maintained in DMEM/10%FCS expressed type-I collagen. The pellets cultured in DMEM/ITS+/TGF-beta1 were larger and contained significantly greater amounts of DNA and glycosaminoglycans. This study suggests that the use of a defined medium containing TGF-beta is necessary to induce the re-expression of a differentiated chondrocytic phenotype and the subsequent stimulation of glycosaminoglycan and type-II collagen production by human monolayer expanded chondrocytes.

The influence of drawing parameters on the mechanical properties of two beta-titanium alloys.

The total cold reduction and reduction per pass used during the drawing of fine wires affected the mechanical properties of two beta-titanium alloys. Both Ti-11.5Mo-6Zr-4.5Sn and Ti-13V-11Cr-3Al showed increased yield strengths and low moduli of elasticity, which resulted in wires appropriate for orthodontic application.

The flexure modulus of elasticity of orthodontic wires.

The flexure moduli of elasticity of solid and multi-stranded orthodontic wires were determined. Results for the solid wires approximated their tensile values, but the differences were statistically significant for the stainless steel, chromium-cobalt-nickel, and nickel-titanium alloys. The flexure moduli of the multi-stranded wires ranged from 0.89 to 5.11 X 10(6) psi, and were dependent on the direction of activation.

Reduction in the modulus of elasticity in orthodontic wires.

The modulus of elasticity of stainless steel orthodontic wires was found to be 20% below the normally assumed range of 19.3 to 20.0 x 10(4) MPa (28.0 to 29.0 x 10(6) psi). Use of the latter value can result in significant computational errors in orthodontic applicance mechanics. The lower modulus was attributed to severe cold drawing.

Flexure modulus of orthodontic stainless steel wires.

The flexure modulus of elasticity of standard stainless steel orthodontic wires was determined by the use of an iterative finite element technique to be 25.4 x 10(6) psi (175 x 10(3) MN/m2). This technique accounts for the configurational changes in the test specimens due to the relatively large deflection during the cantilever test. Under these conditions, the elementary strength of materials relationships does not accurately describe the flexure characteristics of the wires.

Polyurethane elastomers as maxillofacial prosthetic materials.

A series of polyurethane elastomers based on an aliphatic diisocyanate and a polyether macroglycol was polymerized with various cross-link densities and OH/NCO ratios. Stoichiometries yielding between 8,600 and 12,900 gm/mole/crosslink and an OH/NCO ratio of 1.1 resulted in polymers with the low modulus, yet high strength and elongation necessary for maxillofacial applications.

Clinical evaluation methods for posterior composite restorations.

Two methods of evaluating the in vivo wear of posterior composite restorations are described and compared with the USPHS direct clinical evaluation system. The three methods were consistent among themselves and over the two years of the study. In order of increasing sensitivity, the methods were: USPHS, total ranking of models, and categorizing of models according to a set of standards. The last procedure identified statistically significant differences (p less than 0.05) between the composite formulations as early as the nine-month recall. All formulations experienced increasing wear with time, but at a decreasing rate.

Plastic deformation of orthodontic wires.

Theoretical predictions of the bending moments in the region of plastic behavior were accurate for beta titanium and stainless steel, but were consistently low in the far-elastic region for the three alloys studied.

Shear in flexure of fiber composites with different end supports.

The integrity of fiber-reinforced composite (FRC) prostheses is dependent, in part, on flexural rigidity. The object of this study was to determine if the flexure behavior of uniform FRC beams with restrained or simply supported ends and various length/depth (L/d) aspect ratios could be more accurately modeled by correcting for shear. Experimental results were compared with three analytical models. All models were accurate at high L/d ratios, but the shear-corrected model was accurate to the lowest, more clinically relevant, L/d values. In this range, more than 40% of the beam deflection was due to shear.

Comparison of in vitro and in vivo wear of composites.

In vitro wear data were determined for nine experimental composites and compared with two-year clinical data. The in vitro tests included single-pass wear and two-body abrasion. The in vivo data were obtained between 1978 and 1980 for 54 class 2 posterior composite restorations in 25 patients. Correlations between the in vitro and in vivo data were found with values of alpha less than 0.08.

Free-focus radiography using conventional films--radiation exposures in a simulated clinical study.

This study compared air exposures during conventional dental and maxillofacial radiography and similar views using free-focus radiography with conventional image receptors. The results show that periapical type surveys on nonscreen film placed extraorally or in the buccal fold may be carried out with an exposure to the surface tissues, which is similar to or less than conventional dental radiography. Extraoral survey type radiographs of the jaws may be carried out with significantly less surface exposure than lateral oblique views of the jaws. The least exposure was required, when the film was placed in the buccla fold instead of against the face during free-focus radiography. The exposures with film screen combinations were reduced by an order of magnitude when compared to the nonscreen techniques. Proper filtration of the beam of the miniaturized x-ray machines radiography in dentistry may thus be desirable and applications in other parts of the body encouraged.

Utility of the routine chest X-ray after "over-wire" venous catheter changes.

The Seldinger technique is commonly used to change central venous access catheters in the Intensive Care Unit. These catheters are routinely being changed to prevent septic complications. Some of these changes are performed by an "over-wire" technique. To assess the utility of postprocedural chest X-rays on critically ill patients after an over-wire catheter change, we followed 68 patients after they had 80 catheter changes. This study assesses catheter position by use of a postprocedural X-ray. During the study, we found no misplaced catheters and minimum symptomatology in 80 patients. The trauma/critical care fellows performing the procedures rated them as easy in 97.5 percent of the changes. The conclusion of the study is that, if the catheter change is technically easy and the patient has no symptoms, a postprocedural X-ray is not necessary.

The use of continuous fiber reinforcement in dentistry.

Fiber-reinforced composite (FRC) formulations were developed to serve as structural components for various dental appliances such as prosthodontic frameworks, retainers and splints. Poly(ethylene terephthalate glycol) and poly(1,4-cyclohexylene dimethylene terephthalate glycol) reinforced with continuous S-2 glass fibers were pultruded into continuous lengths with small rectangular cross sections. The microstructure was evaluated with SEM and optical microscopy. Fiber content and flexure properties were measured and compared to previous results by other authors. The present FRC contained 43-45 volume % fiber, which compared favorably with the 5-15 volume % fiber reported by all earlier investigators of dental FRC. The present materials achieved 65% of the theoretically expected modulus, in contrast to the typical value of 40% calculated in the earlier reports. The flexural strength and modulus of the experimental FRC were approximately 565 MPa and 20 GPa, respectively. The present FRC can be formed into individualized devices, and free fibers need not be manipulated by the operator. The improved properties and handling justify further study of these FRC as structural dental materials.

Direct and indirect evaluation of posterior composite restorations at three years.

The purpose of this study was to compare the use of direct (USPHS) and indirect (M-L) systems of evaluating the occlusal wear of posterior composite restorations. Additionally, this study has utilized the USPHS method to compare the in vivo performance of posterior resin composite restorations made from four different visible-light-cured materials. Of the 202 restorations placed for this randomized clinical trial, only those restorations that were scored by both direct and indirect evaluation systems were included in these comparisons. Restorations were evaluated by two calibrated examiners from baseline to 36 months. While there were some differences noted among the four materials, the majority (99%) of the restorations evaluated in this study received "alpha" or "bravo" scores for all USPHS parameters, indicating acceptable in vivo performance. The results of this study also indicate that there was a consistent relationship between the direct (USPHS) and indirect (M-L scale) scoring systems. For those restorations that changed anatomic form scores, the mean wear at the alfa/bravo transition was 100 +/- 80 microns. By the 24-month recall examination, the use of the USPHS evaluation system category of anatomic form enabled examiners to differentiate restorations and materials that had experienced little occlusal wear from those that had experienced greater amounts of wear.

Three-year occlusal wear of posterior composite restorations.

The specific aims of this study were to: 1) measure the occlusal wear of four different dental composite materials placed in the posterior teeth of adults; and 2) evaluate the effect of the clinical parameters, cavity class and tooth type on occlusal wear. Four different visible light-cured composite materials were used to make the restorations in this study. The restorations placed for this randomized clinical trial were scored through the use of an indirect evaluation system (M-L scale). The total sample size per recall ranged from 90 to 142 restorations from baseline to 36 months. The mean wear at 36 months for Heliomolar, J&J Experimental (Adaptic II) and P-30 was 45-54 microns, which is rather low compared to the recently reported wear of other composite materials. Marathon exhibited significantly greater wear with a mean of 174 microns at 36 months. The data also showed that cavity class and tooth type had no significant effect on the occlusal wear of the restorations made with the three low wear-rate materials, while restorations composed of the high wear-rate material exhibited more wear in molars than premolars; this effect was again not statistically significant. These data support the hypothesis that the overall wear of a composite restoration is more dependent on the material's properties than clinical parameters such as cavity class and tooth type.

Continuous fiber reinforced composite materials as alternatives for metal alloys used for dental appliances.

Two types of uniaxially oriented long S2-glass fiber reinforced composites were prepared for use in various dental appliances. Matrix polymers were polycarbonate (PC) and bisphenol A bis (2-hydroxy-propyl) methacrylate (Bis-GMA) based copolymers. Flexural tests were conducted on the composites using a procedure which simulates clinical usages. To evaluate the adhesion between the composites and the adhesive, the single-lap shear test was conducted. Mechanical properties of the small cross-sectional composite strips were superior to those used previously in clinical studies.

An innovative pre-impregnated glass fiber for reinforcing composites.

This article summarized the development of pre-impregnated, fiber-reinforced composites. Previous efforts with various reinforcement materials for splinting are cited. The benefits of pre-impregnation are explained. The clinical procedure for placing a fiber-reinforced composite splint is described.