Scanning Electron Microscopic Assessment of Stent Coating Integrity in Jailed Wire Technique for Bifurcation Treatment.

OBJECTIVES: To assess the impact of different guidewires on stent coating integrity in jailed wire technique (JWT) for bifurcation treatment. BACKGROUND: JWT is commonly adopted to protect side branch in provisional one-stent strategy for coronary bifurcation lesions. However, this technique may cause defects in stent coatings. The degree of coating damage caused by different types of jailed wires remains unknown. METHODS: A fluid model with a bifurcation was established to mimic the condition in vivo. One-stent strategy was performed with three types of guidewire (nonpolymer-jacketed wire, intermediate polymer-jacketed wire, and full polymer-jacketed wire) tested for JWT. Scanning electron microscopy (SEM) was used to evaluate stent coating integrity and wire structure. The degrees of coating defects were recorded as no, slight, moderate, and severe defects. RESULTS: A total of 27 samples were tested. Analyses of SEM images showed a significant difference in the degree of coating damage among the three types of wire after the procedure of JWT (P < 0.001). Nonpolymer-jacketed wire could inevitably cause a severe defect in stent coatings, while full polymer-jacketed wire caused the least coating damages. Besides, there were varying degrees of coil deformation in nonpolymer-jacketed wires, while no surface damage or jacket shearing was observed in full polymer-jacketed wires. CONCLUSIONS: Although nonpolymer-jacketed wire has long been recommended for JWT, our bench-side study suggests that full polymer-jacketed wire may be a better choice. Further clinical studies are needed to confirm our findings.

Knee Prosthesis in the Computer Era.

Over the past two decades, computer assistance has revolutionalized surgery and has enabled enormous advancements in knee prosthesis surgery. Total knee arthroplasty (TKA) is a hot topic of orthopaedic research. Reflecting population dynamics, its use continues to increase, especially in high demand populations. Therefore, efforts to achieve the best fit and precise alignment in TKA continue. Computer assistance is valuable for knee prosthesis surgeons in this regard. This manuscript investigated the use of computer assistance in knee prosthesis surgery. The effects of computer use on important facets of knee prosthesis surgery, such as precision, clinical aspects, and costs, were examined. Moreover, an overall review of the recent literature on the navigation and personalized cutting guides was conducted.

A Prospective Assessment of an Adjustable, Immediate Fit, Transtibial Prosthesis.

BACKGROUND: There exists a need for an adjustable socket to accommodate residual limb volume and shape changes. Further, limb loss rates globally are rising and there is a large unmet need for affordable and accessible prosthetic systems. OBJECTIVE: To assess the utility of an immediate fit modular prosthetic system (iFIT Prosthetics, LLC). DESIGN: Prospective feasibility study involving a 2-week single-group pre-post intervention study. SETTING: Physical Medicine and Rehabilitation gait laboratory. PARTICIPANTS: Participants were at least 6 months post amputation and walking with a conventional prosthesis. They were free of skin wounds, other neurological disorders, and severe pain conditions. METHODS: Participants were fit with an immediate fit prosthesis and instructed to wear it for a 2-week evaluation period. They were given a progressive wearing schedule and they completed outcome measurements at the 2-week follow-up. MAIN OUTCOME MEASUREMENTS: Self-reported satisfaction, gait biomechanics, and intrasocket peak pressures. RESULTS: Twenty-six participants entered the study, with 22 completing the single group pre-post study. They averaged 50 years (SD ±10.2) of age; four were female. Sixteen were dysvascular and 10 were traumatic in etiology. Significant differences (P = .03) in self-reported satisfaction were found in favor of the iFIT device 29.33 (SD ± 4.51) versus the conventional device 25.52 (SD ± 6.8). No falls or limb ischemia were reported. Gait biomechanics revealed no differences across any temporal characteristics. Intrasocket peak pressures were significantly lower for the iFIT prostheses overall (P = .0014), at the anterior tibia (P = .0002), and the lateral side of the residual limb (P = .013). CONCLUSIONS: The iFIT transtibial prosthetic system appears to be safe in this short-term single-group pre-post study. This study provided preliminary evidence to support the feasibility of the iFIT system. It compared favorably to participants' conventional prostheses across all outcome measures. With its cost, adjustability, and accessibility advantages, this device may prove useful for persons with transtibial amputations. A larger multicenter study is needed to confirm these results. LEVEL OF EVIDENCE: III.

Scleral lens fitting and assessment strategies.

PURPOSE: To describe prescriber reported scleral lens fitting and assessment strategies. METHODS: The SCOPE (Scleral Lenses in Current Ophthalmic Practice Evaluation) study group designed and administered an IRB approved, electronic survey (REDCap) regarding current scleral lens fitting and assessment methods. The survey was distributed to attendees of the 2017 Global Specialty Lens Symposium. RESULTS: 95 practitioners responded to the survey. Over half of the respondents, 58% (55/95) reported fitting scleral lenses for less than five years (new prescribers), and 42% (40/95) reported fitting scleral lenses for more than five years (experienced prescribers). There was a statistically significant difference between their initial use of technology (χ2 = 21.117, p < 0.0005) in selection of a diagnostic lens. New prescribers consider base curve first (60%, 33/55), while experienced prescribers considered sagittal depth first (63%, 25/40) in their initial scleral lens selection. All of the experienced lens prescribers (100%, 39/39) reported estimating central clearance by comparing thickness of the post-lens tear reservoir to scleral lens thickness using a slit lamp beam at least some of the time, and 62% of new scleral lens prescribers (34/55; χ2 = 19.175, p < 0.0005) reported doing so. All (100%, 40/40) experienced prescribers schedule scleral lens follow-ups at a specific time and assess conjunctival compression (100%, 40/40), conjunctival staining (100%, 39/39), and corneal staining (100%,40/40) after lens removal. CONCLUSIONS: Practitioners with varying backgrounds and experience have added sclerals to their lens inventories. However, definite guidelines for fitting have not been developed. The results of a survey are provided; demonstrating that among practitioners with greater than 5 years of scleral lens experience, a consensus has emerged for best practices. Strategies for lens evaluation, which may inform future efforts at generating scleral fitting standards are described.

In vivo assessment of the anterior scleral contour assisted by automatic profilometry and changes in conjunctival shape after miniscleral contact lens fitting.

PURPOSE: To compare the shape of the anterior sclera of candidates to scleral lens (ScCL) fitting with regular and irregular corneas and analyze the changes induced in the shape of the sclero-conjunctiva after ScCL wear. METHODS: Thirty-five eyes of 18 subjects (19 eyes with irregular corneas and 16 with regular corneas) were consecutively recruited. Three measures of sclero-conjunctival shape were taken with Eye Surface Profiler (ESP, Eaglet Eye, Houten, The Netherlands). Tangent angles and ocular sagittal heights (OC-SAG) were analyzed at different chords from 13 to 17mm in the nasal, temporal, superior and inferior regions. The 19 eyes with irregular cornea were selected to wear ScCL and the changes in their sclero-conjunctival surface parameters were compared before and after 3h of lens wear. RESULTS: Irregular corneas showed higher OC-SAG values than regular corneas in all the chords analyzed, with statistical significant differences in the temporal region. Regarding tangent angles, regular corneas showed lower values (flatter surface), with statistical significant differences at 8 and 8.50mm on the nasal and 8.50mm on the temporal region. Some changes were seen in sclero-conjuctival shape after short-term ScCL wear. There was an augment in OC-SAG after 3h of scleral lens wear and a reduction on tangent angles, namely on the nasal region at 7.5mm and 8.00mm chord lengths, which is coincidental with the landing zone of ScCL. CONCLUSIONS: ESP shows mild differences in scleral shape between eyes with regular and irregular corneas. ESP might be valuable in quantifying the mechanical impact of the ScCL on the anterior eye surface.

Computed Tomography Assessment for Transcatheter Aortic Valve Replacement.

Transcatheter aortic valve replacement has become a mainstream therapeutic option for patients with severe aortic stenosis who are at intermediate risk or high risk for surgical valve replacement. Computed tomography (CT) is now the standard imaging modality for preoperative vascular access planning an aortic annular sizing. This article reviews the established and potential future roles of CT in transcatheter aortic valve replacement.

Iodine-Starch test for assessment of hyperhidrosis in amputees, evaluation of different methods of application.

PURPOSE: Hyperhidrosis is a common problem for amputees. The iodine-starch test is frequently used to assess hyperhidrosis, but a method for its application has not been described for amputees. METHODS: We performed an unblinded comparison of the iodine-starch test using various methods to protect the prosthesis in 10 prosthetic limb users with hyperhidrosis. RESULTS: Plastic wrap produced a diffuse pattern of sweating in 70% of subjects. Forty percent had complaints about this method, and 50% experienced leakage of iodine stain onto prosthetic liners. The prosthetic sheath produced a focal or multifocal reaction in 100% of subjects after 10 min of ambulation. Eighty percent had minor leakage onto the liner, and complaints were noted in 10%. The proportion that experienced diffuse sweating was significantly higher in the plastic wrap condition (p = 0.016; difference in proportions = 70%; 95% confidence interval = 32-100%). The prosthetic sock was tested in four subjects and all had at least mild complaints; three had minor leakage onto the liner. Repeated complaints and lack of stain prevention led to discontinuation with this method. CONCLUSIONS: Of the three methods, the sheath produces a focal or multifocal reaction after 10 min of ambulation and tends to cause less subject complaints. It should be the preferred method to apply the iodine-starch test to amputees. Implications for rehabilitation Hyperhidrosis is a common problem in amputees which negatively affects quality of life. The iodine-starch test is commonly used to guide treatment decisions for hyperhidrosis, but a preferred method for applying it in amputees has not been described. This study describes different methods for applying the iodine-starch test. A prosthetic sheath covering should be the preferred method for the iodine-starch test in amputees.

Cost-effectiveness of bone-anchored prostheses using osseointegrated fixation: Myth or reality?

BACKGROUND: In principle, lower limb bone-anchored prostheses could alleviate expenditure associated with typical socket manufacturing and residuum treatments due to socket-suspended prostheses. OBJECTIVE: This study reports (a) the incremental costs and (b) heath gain as well as (c) cost-effectiveness of bone-anchored prostheses compared to socket-suspended prostheses. STUDY DESIGN: Retrospective individual case-controlled observations and systematic review. METHODS: Actual costs were extracted from financial records and completed by typical costs when needed over 6-year time horizon for a cohort of 16 individuals. Health gains corresponding to quality-adjusted life-year were calculated using health-related quality-of-life data presented in the literature. RESULTS: The provision of bone-anchored prostheses costed 21% ± 41% more but increased quality-adjusted life-years by 17% ± 5% compared to socket-suspended prostheses. The incremental cost-effectiveness ratio ranged between -$25,700 per quality-adjusted life-year and $53,500 per quality-adjusted life-year with indicative incremental cost-effectiveness ratio of approximately $17,000 per quality-adjusted life-year. Bone-anchored prosthesis was cost-saving and cost-effective for 19% and 88% of the participants, respectively. CONCLUSION: This study indicated that bone-anchored prostheses might be an acceptable alternative to socket-suspended prostheses at least from a prosthetic care perspective in Australian context. Altogether, this initial evidence-based economic evaluation provided a working approach for decision makers responsible for policies around care of individuals with lower limb amputation worldwide. Clinical relevance For the first time, this study provided evidence-based health economic benefits of lower limb bone-anchored prostheses compared to typical socket-suspended prostheses from a prosthetic care perspective that is essential to clinicians and decision makers responsible for policies.

Mild-moderate congenital hearing loss: secular trends in outcomes across four systems of detection.

BACKGROUND: Universal newborn hearing screening (UNHS) targets moderate or greater hearing loss. However, UNHS also frequently detects children with mild loss that results in many receiving early treatment. The benefits of this approach are not yet established. We aimed to (i) compare language and psychosocial outcomes between four hearing loss detection systems for children aged 5-8 years with congenital mild-moderate hearing loss; (ii) determine whether age of detection predicts outcomes; and (iii) compare outcomes between children identified via well-established UNHS and the general population. METHODS: Linear regression adjusted for potential confounding factors was used throughout. Via a quasi-experimental design, language and psychosocial outcomes were compared across four population-based Australian systems of hearing loss detection: opportunistic detection, born 1991-1993, n = 50; universal risk factor referral, born 2003-2005, n = 34; newly established UNHS, born 2003-2005, n = 41; and well-established UNHS, born 2007-2010, n = 21. In pooled analyses, we examined whether age of detection predicted outcomes. Outcomes were similarly compared between the current well-established UNHS system and typically developing children in the Early Language in Victoria Study, born 2003, n = 1217. RESULTS: Age at diagnosis and hearing aid fitting fell steadily across the four systems. For moderate losses, mean expressive language (P for trend .05) and receptive vocabulary (P for trend .06) improved across the four systems, but benefit was not obvious for mild losses. In pooled analyses, diagnosis before age six months predicted better language outcomes for moderate losses. Children with mild-moderate losses exposed to well-established UNHS continue to experience expressive language scores well below children in the general population (adjusted mean difference -8.9 points, 95% CI -14.7 to -3.1). CONCLUSIONS: Treatment arising from UNHS appears to be clearly benefitting children with moderate hearing losses. However, rigorous trials are needed to quantify benefits, versus costs and potential harms, of early aiding of children with mild losses.

Use of programmable versus nonprogrammable shunts in the management of normal pressure hydrocephalus: A multicenter retrospective study with cost-benefit analysis in Turkey.

Ventriculoperitoneal shunt systems that are used in the treatment of normal pressure hydrocephalus are often associated with drainage problems. Adjustable shunt systems can prevent or treat these problems, but they may be expensive. The aim of our study is to compare the complications and total cost of several shunt systems.Patients with normal pressure hydrocephalus who underwent ventriculoperitoneal shunting between 2011 and 2016 were included in the study. The study involves patient consent and the informed consent was given. Complications and the average cost per person were compared between patients with adjustable and nonadjustable shunts. Shunt prices, surgical complications, and revision costs were taken into account to calculate the average cost.Of the 110 patients who were evaluated, 80 had a nonadjustable shunt and 30 had an adjustable shunt. In the group with adjustable shunts, the rates of subdural effusion and hematoma were 19.73% and 3.29%, respectively. In the group with nonadjustable shunts, these rates were 22.75% and 13.75%, respectively. One patient in the adjustable group underwent surgery for subdural hematoma, while 8 patients in the nonadjustable group underwent the same surgery. Ten patients required surgical intervention for subdural effusion and existing shunt systems in these patients were replaced by an adjustable shunt system. When these additional costs were factored into the analysis, the difference in cost between the shunt systems was reduced from 600 United States dollars (USD) to 111 USD.When the complications and additional costs that arise during surgical treatment of normal pressure hydrocephalus were considered, the price difference between adjustable and nonadjustable shunt systems was estimated to be much lower.

Aortic Valve Annular Sizing: Intraoperative Assessment Versus Preoperative Multidetector Computed Tomography.

BACKGROUND: Appropriate valve sizing is critical in aortic valve replacement. We hypothesized that direct intraoperative valve sizing results in smaller aortic annular diameters compared with sizing based on systolic-phase multidetector computerized tomographic (MDCT) imaging. METHODS AND RESULTS: We retrospectively analyzed 78 patients undergoing surgical aortic valve replacement for severe aortic stenosis between 2012 and 2014 at our institution. Preoperative MDCT measurements of the aortic annulus served as basis for assignment to a theoretical surgical valve size, which was then (1) compared to the implanted valve size and (2) to a theoretical transcatheter aortic valve replacement valve size. To quantify the resulting differences, geometric orifice areas (GOA) were calculated. MDCT-based sizing produced the same valve size for n=34 patients (group CT-same), a larger valve with a 25% increased GOA in n=32 patients (group CT-Lg) and a smaller GOA by 22% in n=12 patients (group CT-Sm). On the basis of MDCT measurements, 41% of valves implanted were undersized. The comparison of intraoperative implanted to a theoretical transcatheter aortic valve replacement valve size resulted in GOAs 25% larger for patients in group CT-same, 40.6% larger in group CT-Lg and 14.6% larger in group CT-Sm. CONCLUSIONS: Preoperative MDCT measurements differ substantially from direct intraoperative assessment of the aortic annulus. Implanted surgical aortic valve replacement valves were smaller relative to MDCT-based sizing in 41% of patients, and the potential GOA was between 25% and 40.6% larger if patients had undergone transcatheter aortic valve replacement.

The development of a low-cost three-dimensional printed shoulder, arm, and hand prostheses for children.

BACKGROUND AND AIM: The prosthetic options for higher level amputees are limited and costly. Advancements in computer-aided design programs and three-dimensional printing offer the possibility of designing and manufacturing transitional prostheses at very low cost. The aim of this project was to describe an inexpensive three-dimensional printed mechanical shoulder prosthesis to assist a pre-selected subject in performing bi-manual activities. TECHNIQUE: The main function of the body-powered, manually adjusted three-dimensional printed shoulder prosthesis is to provide a cost-effective, highly customized transitional device to individuals with congenital or acquired forequarter amputations. DISCUSSION: After testing the prototype on a young research participant, a partial correction of the patient's spinal deviation was noted due to the counterweight of the device. The patient's family also reported improved balance and performance of some bimanual activities after 2 weeks of using the device. Limitations of the design include low grip strength and low durability. Clinical relevance The prosthetic options for higher level amputees are limited and costly. The low-cost three-dimensional printed shoulder prosthesis described in this study can be used as a transitional device in preparation for a more sophisticated shoulder prosthesis.

Accuracy Assessment of Using Rapid Prototyping Drill Templates for Atlantoaxial Screw Placement: A Cadaver Study.

Purpose. To preliminarily evaluate the feasibility and accuracy of using rapid prototyping drill templates (RPDTs) for C1 lateral mass screw (C1-LMS) and C2 pedicle screw (C2-PS) placement. Methods. 23 formalin-fixed craniocervical cadaver specimens were randomly divided into two groups. In the conventional method group, intraoperative fluoroscopy was used to assist the screw placement. In the RPDT navigation group, specific RPDTs were constructed for each specimen and were used intraoperatively for screw placement navigation. The screw position, the operating time, and the fluoroscopy time for each screw placement were compared between the 2 groups. Results. Compared with the conventional method, the RPDT technique significantly increased the placement accuracy of the C2-PS (p < 0.05). In the axial plane, using RPDTs also significantly increased C1-LMS placement accuracy (p < 0.05). In the sagittal plane, although using RPDTs had a very high accuracy rate (100%) in C1-LMS placement, it was not statistically significant compared with the conventional method (p > 0.05). Moreover, the RPDT technique significantly decreased the operating and fluoroscopy times. Conclusion. Using RPDTs significantly increases the accuracy of C1-LMS and C2-PS placement while decreasing the screw placement time and the radiation exposure. Due to these advantages, this approach is worth promoting for use in the Harms technique.

[Special Intraocular Lenses in Refractive Lens Surgery]. / Sonderlinsen in der refraktiven Chirurgie.

PURPOSE: Many different models and types of special intraocular lenses (IOL) are now available for refractive lens surgery. In particular, toric and multifocal IOL need specific conditions to achieve satisfactory results. For multifocal IOL, many models with different optical principles are available. For optimal individual patient-centred care, it is necessary to consider several different options. With special refractive lenses, the principle objective for the patients is to become less dependent on glasses. MATERIAL AND METHODS: Different IOL are evaluated on the basis of published studies and our own experience and data. RESULTS: IOL filtering blue light should not be classified as special IOL, but should be used as standards. Aspherical IOL are only beneficial in special situations. Toric IOL give reliable and good results, as long as certain specific requirements are considered. Multifocal IOL are still an optical compromise, although they are the only IOL that can reliably make the patient independent of glasses. To achieve satisfying results, the optimal IOL model should be selected individually. CONCLUSION: Many refractive needs can now be adequately satisfied by special IOL. The surgeon should provide ideal perioperative conditions, and he should be aware of the different IOL principles if he is to give the patient optimal advice. This can help to avoid upsetting both patients and ophthalmologists.

Single-Use Instrumentation Technologies in Knee Arthroplasty: State of the Art.

The surgical site contamination and the resulting periprosthetic infections are an important cause of morbidity and socio-economic impact. In total knee arthroplasty, the single-use instrumentation is developed to simplify the surgical procedure, reduce the chance of instrument contamination, improve the operating room efficiency, and reduce overall costs (low cost of instrument washing and sterilization as well as personnel management). Surgical single-use instrumentations on the market are complete with all you need for the surgical procedure-cutting guides, conventional or PSI (patient-specific instrumentation), femoral cutting block, re-cutting block, trials components, alignment rods, inserts, and impactors. In recent years, PSI (patient-specific instrumentation) was introduced. It decreases operative time and blood loss without violating the intramedullary canal. It also allows the surgeon to preoperatively plan the patient's component size, position, and alignment. We reported an average of 30 minutes saved for each surgical procedure, a saving of 60€ for each surgical tray. Moreover, we avoided surgery cancellation or delay due to un-sterile, missing, or dysfunctional instruments. We think that this technology is the first step in developing implants that are entirely customized for each patient, and we believe that it will have a more relevant role in knee surgery in the future.

Assessment of mandibular posterior regional landmarks using cone-beam computed tomography in dental implant surgery.

The aim of this study has been to evaluate and correlate the anatomical features of the posterior mandibular region (submandibular fossa depth, bone height and thickness, and mandibular canal corticalization) to improve accident prevention and allow safe planning in implantology. Four parasagittal sections of cone-beam computed tomography (CBCT) from 100 patients were bilaterally analyzed. Linear measurements of the submandibular fossa depth, bone height and thickness were performed. The submandibular fossa was also classified into non-influential undercuts and influential undercuts for implant placement. Mandibular canal corticalization was also evaluated and classified according to the visualization. Data on patient age and gender were also collected. Forty-one scans (41%) were from male patients, and 59 (59%) were from female patients. Patient age ranged between 18 and 84 years, with an average age of 51.37 years. The submandibular fossa depth and implant bone thickness had a significant effect on the variability of the sample (46.1% and 22.3%, respectively). The submandibular fossa depth was quite variable, and the highest values were observed in the posterior regions. In 18.27% of the cases, the presence of the fossa directly influenced implant placement, considering a bone height of 10mm (standard implant). A significant correlation was observed between fossa depth and bone thickness. Thus, greater attention should be paid to thick ridges; although thick ridges are favorable, they may be associated with deeper submandibular fossae. The mandibular canal was the most influential anatomical structure in the premolar region due to the reduced bone height in this region and the greater difficulty in viewing the canal, and the submandibular fossa was the most influential structure in the molar region due to lower bone height leading up to the fossa and the greater fossa depth in this region. Therefore, CBCT is an important tool for assessing the mandibular region and planning for safe implant installation in the posterior mandible. Furthermore, comprehensive evaluation of the characteristics of this region is necessary, as the variables - submandibular fossa depth, bone height and thickness, and mandibular canal corticalization - are related and must be considered together when planning.

[Bearing selection in total hip arthroplasty]. / Wahl der richtigen Gleitpaarung in der Hüftendoprothetik.

Different bearing materials are available in total hip arthroplasty and it's the surgeon who has the choice between hard-on-soft, hard-on-hard and alternative materials. Ideally, the material selection should rely on evidence-based data regarding the wear performance, the incidence of revision surgery and other potential bearing-associated risk factors for the corresponding combinations of materials in the individual patient. While there are high-quality studies available for some materials, adequate data is lacking for other materials. Therefore, the current article aims to provide bearing selection criteria for the surgeon and to review the current literature regarding different combinations of bearing materials in total hip arthroplasty.

Endovascular Treatment of Acute Stroke: Evolution and Selection of Techniques and Instruments Based on Thrombus Imaging.

Mechanical thrombectomy provides higher recanalization rates than intravenous or intra-arterial thrombolysis. Finally this has been shown to translate into improved clinical outcome in six multicentric randomized controlled trials. However, within cohorts the clinical outcomes may vary, depending on the endovascular techniques applied. Systems aiming mainly for thrombus fragmentation and lacking a protection against distal embolization have shown disappointing results when compared to recent stent-retriever studies or even to historical data on local arterial fibrinolysis. Procedure-related embolic events are usually graded as adverse events in interventional neuroradiology. In stroke, however, the clinical consequences of secondary emboli have so far mostly been neglected and attributed to progression of the stroke itself. We summarize the evolution of instruments and techniques for endovascular, image-guided, microneurosurgical recanalization in acute stroke, and discuss how to avoid procedure-related embolic complications.

[Intraoperative Evaluation of Total Knee Arthroplasty: Anatomic and Kinematic Assessment with Trial Components]. / Intraoperative Analyse der Anatomie und Kinematik in der Knieendoprothetik.

The intraoperative use of trial components in total knee arthroplasty (TKA) is of paramount importance to prevent inadequate ligament balance and to achieve optimal position of the definitive components. This review demonstrates an 8-step algorithm to assess the anatomy of the femoral, tibial and patellar component as well as the kinematics of the tibiofemoral and patellofemoral joints. Trial components allow an easy assessment of the anatomic fit of the final implants. Upon the trials insertion, bone coverage and the component overhang should be evaluated. The femoral rotation should be assessed using the transepicondylar axis and for the tibial component rotation assessment, the tibial tuberosity would be the most reliable bony landmark. Addressing the patella, sizing and bone coverage should be thoroughly evaluated. In order to restore physiological kinematics the remnants of the meniscus rim can be used to determine the correct reconstruction of the joint line. A tight extension gap results in limited extension, whereas a tight or unbalanced flexion gap leads to "booking" or "spin-out" of the inlay. The POLO test (pull-out, lift- off) allows an easy assessment of the posterior cruciate ligament tension and the size of the flexion gap as well. To prevent postoperative dislocation and overstuffing, specific tests for correct patellar positioning and tracking support should be performed. The anatomy and kinematics of total knee arthroplasty have to be evaluated by trial components on a routine basis before inserting the final implants in order to identify implant positioning errors and inadequate ligament balance.

Assessment of multifocal contact lens over-refraction using an infrared, open-field autorefractor: A preliminary study.

PURPOSE: To evaluate the usefulness of an infrared open-field autorefractor as a predictor of the refractive error when fitting multifocal contact lenses (MCL). METHODS: Objective and subjective measurements of the non-cycloplegic distance refractive error were compared in patients wearing MCL. We used the Grand Seiko WAM-5500 autorefractor for the objective measurements. Three commercially available MCL were tested. Twenty-one eyes of sixteen healthy adults were included in the study. Over-refraction was evaluated in terms of spherical equivalent (SE) and astigmatic vectors (J0 and J45). The mean difference±SD of each parameter was calculated. The Kolmogorov-Smirnov test was used to verify the normal distribution. Pearson's correlation, Bland and Altman plot and paired sample t test were used to compare the results obtained with both methods. RESULTS: The mean difference between objective and subjective results of the SE over-refraction was 0.13±0.42D; for astigmatic vectors J0 and J45 were 0.03±0.32D and -0.00±0.17D, respectively. The Kolmogorov-Smirnov test showed a normal distribution for all parameters. The highest Pearson's correlation coefficients were obtained for the SE with values of 0.98 without MCL and 0.97 with MCL. The lowest were obtained for J45 with values of 0.65 without MCL and 0.75 with MCL. Significant correlations were obtained for each parameter. The paired sample t test failed to show significant differences in analyzed parameters except for J0 without MCL. CONCLUSIONS: The Grand Seiko WAM-5500 can be used as a screening method of over-refraction in the clinical fitting of MCL.