Improving the diagnostic performance of inexperienced readers for thyroid nodules through digital self-learning and artificial intelligence assistance.

Background: Data-driven digital learning could improve the diagnostic performance of novice students for thyroid nodules. Objective: To evaluate the efficacy of digital self-learning and artificial intelligence-based computer-assisted diagnosis (AI-CAD) for inexperienced readers to diagnose thyroid nodules. Methods: Between February and August 2023, a total of 26 readers (less than 1 year of experience in thyroid US from various departments) from 6 hospitals participated in this study. Readers completed an online learning session comprising 3,000 thyroid nodules annotated as benign or malignant independently. They were asked to assess a test set consisting of 120 thyroid nodules with known surgical pathology before and after a learning session. Then, they referred to AI-CAD and made their final decisions on the thyroid nodules. Diagnostic performances before and after self-training and with AI-CAD assistance were evaluated and compared between radiology residents and readers from different specialties. Results: AUC (area under the receiver operating characteristic curve) improved after the self-learning session, and it improved further after radiologists referred to AI-CAD (0.679 vs 0.713 vs 0.758, p<0.05). Although the 18 radiology residents showed improved AUC (0.7 to 0.743, p=0.016) and accuracy (69.9% to 74.2%, p=0.013) after self-learning, the readers from other departments did not. With AI-CAD assistance, sensitivity (radiology 70.3% to 74.9%, others 67.9% to 82.3%, all p<0.05) and accuracy (radiology 74.2% to 77.1%, others 64.4% to 72.8%, all p <0.05) improved in all readers. Conclusion: While AI-CAD assistance helps improve the diagnostic performance of all inexperienced readers for thyroid nodules, self-learning was only effective for radiology residents with more background knowledge of ultrasonography. Clinical Impact: Online self-learning, along with AI-CAD assistance, can effectively enhance the diagnostic performance of radiology residents in thyroid cancer.

Adverse effects of tamoxifen treatment on bone mineral density in premenopausal patients with breast cancer: a systematic review and meta-analysis.

BACKGROUND: It is well known that adjuvant tamoxifen treatment for breast cancer in postmenopausal women decreased bone loss. However, the effects of adjuvant tamoxifen therapy on bone mineral density (BMD) in premenopausal patients with breast cancer remains uncertain. Tamoxifen would have a potential impact of premenopausal BMD on health. The aim of this meta-analysis was to assess this in premenopausal women with primary breast cancer. METHODS: Through April 2020, studies reporting BMD changes of lumbar spine or hip in premenopausal women with primary breast cancer treated with adjuvant tamoxifen and tamoxifen plus chemotherapy or ovarian function suppression (OFS) were collected from EMBASE and PubMed. The meta-analysis was performed using random effects model of the standardized mean difference (SMD) of BMD in patients. RESULTS: A total of 1432 premenopausal patients were enrolled in eight studies, involving 198 patients treated with tamoxifen alone in three studies. After a 3-year median follow-up, adjuvant tamoxifen decreased the lumbar spinal and hip BMD by as much as an SMD of -1.17 [95% confidence interval (CI); -1.58 to -0.76)] and -0.66 (95% CI, -1.55 to 0.23), respectively. In subgroup analysis in patients treated adjuvant tamoxifen and tamoxifen plus chemotherapy or OFS according to follow-up duration, the bone change of < 3 years follow-up group was -0.03 SMD (95% CI, -0.47 to 0.41) and that of ≥ 3 years follow-up group was -1.06 SMD (95% CI, -1.48 to -0.64). Compared with patients who received tamoxifen alone, patients who received combination therapy with chemotherapy or OFS showed lesser bone loss at the lumbar spine. CONCLUSIONS: Our meta-analysis demonstrated that adjuvant tamoxifen therapy in premenopausal patients caused bone loss after 3 years of follow-up, especially at the lumbar spines. For a definite evaluation of the adverse effects of tamoxifen on bone, it is necessary to accumulate more relevant studies.

Positive Predictive Values of Abnormality Scores From a Commercial Artificial Intelligence-Based Computer-Aided Diagnosis for Mammography.

OBJECTIVE: Artificial intelligence-based computer-aided diagnosis (AI-CAD) is increasingly used in mammography. While the continuous scores of AI-CAD have been related to malignancy risk, the understanding of how to interpret and apply these scores remains limited. We investigated the positive predictive values (PPVs) of the abnormality scores generated by a deep learning-based commercial AI-CAD system and analyzed them in relation to clinical and radiological findings. MATERIALS AND METHODS: From March 2020 to May 2022, 656 breasts from 599 women (mean age 52.6 ± 11.5 years, including 0.6% [4/599] high-risk women) who underwent mammography and received positive AI-CAD results (Lunit Insight MMG, abnormality score ≥ 10) were retrospectively included in this study. Univariable and multivariable analyses were performed to evaluate the associations between the AI-CAD abnormality scores and clinical and radiological factors. The breasts were subdivided according to the abnormality scores into groups 1 (10-49), 2 (50-69), 3 (70-89), and 4 (90-100) using the optimal binning method. The PPVs were calculated for all breasts and subgroups. RESULTS: Diagnostic indications and positive imaging findings by radiologists were associated with higher abnormality scores in the multivariable regression analysis. The overall PPV of AI-CAD was 32.5% (213/656) for all breasts, including 213 breast cancers, 129 breasts with benign biopsy results, and 314 breasts with benign outcomes in the follow-up or diagnostic studies. In the screening mammography subgroup, the PPVs were 18.6% (58/312) overall and 5.1% (12/235), 29.0% (9/31), 57.9% (11/19), and 96.3% (26/27) for score groups 1, 2, 3, and 4, respectively. The PPVs were significantly higher in women with diagnostic indications (45.1% [155/344]), palpability (51.9% [149/287]), fatty breasts (61.2% [60/98]), and certain imaging findings (masses with or without calcifications and distortion). CONCLUSION: PPV increased with increasing AI-CAD abnormality scores. The PPVs of AI-CAD satisfied the acceptable PPV range according to Breast Imaging-Reporting and Data System for screening mammography and were higher for diagnostic mammography.

Diagnostic performance with and without artificial intelligence assistance in real-world screening mammography.

Purpose: To evaluate artificial intelligence-based computer-aided diagnosis (AI-CAD) for screening mammography, we analyzed the diagnostic performance of radiologists by providing and withholding AI-CAD results alternatively every month. Methods: This retrospective study was approved by the institutional review board with a waiver for informed consent. Between August 2020 and May 2022, 1819 consecutive women (mean age 50.8 ± 9.4 years) with 2061 screening mammography and ultrasound performed on the same day in a single institution were included. Radiologists interpreted screening mammography in clinical practice with AI-CAD results being provided or withheld alternatively by month. The AI-CAD results were retrospectively obtained for analysis even when withheld from radiologists. The diagnostic performances of radiologists and stand-alone AI-CAD were compared and the performances of radiologists with and without AI-CAD assistance were also compared by cancer detection rate, recall rate, sensitivity, specificity, accuracy and area under the receiver-operating-characteristics curve (AUC). Results: Twenty-nine breast cancer patients and 1790 women without cancers were included. Diagnostic performances of the radiologists did not significantly differ with and without AI-CAD assistance. Radiologists with AI-CAD assistance showed the same sensitivity (76.5%) and similar specificity (92.3% vs 93.8%), AUC (0.844 vs 0.851), and recall rates (8.8% vs. 7.4%) compared to standalone AI-CAD. Radiologists without AI-CAD assistance showed lower specificity (91.9% vs 94.6%) and accuracy (91.5% vs 94.1%) and higher recall rates (8.6% vs 5.9%, all p < 0.05) compared to stand-alone AI-CAD. Conclusion: Radiologists showed no significant difference in diagnostic performance when both screening mammography and ultrasound were performed with or without AI-CAD assistance for mammography. However, without AI-CAD assistance, radiologists showed lower specificity and accuracy and higher recall rates compared to stand-alone AI-CAD.

Impact of the ACOSOG Z0011 trial on surgical practice in Asian patients: trends in axillary surgery for breast cancer from a Korean Breast Cancer Registry analysis.

BACKGROUND: Since the publication of the Z0011 trial, practice-changing clinical guidelines for breast surgery have been developed. Although recent studies confirmed the feasibility of the Z0011 strategy in Asian populations, there has been no study on the trends of axillary surgery in Asian cohort. This study aimed to investigate the time trend of axillary surgery for breast cancer from a Korean Breast Cancer Registry to understand the impact of the Z0011 trial in Asian patients. METHODS: We collected prospectively constructed data from the nationwide Korean Breast Cancer Registry (KBCR). We identified patients who underwent sentinel node biopsy followed by breast-conserving surgery from 2011 to 2018 and were found to have pathological stage T1-2N1-3M0 disease. Regression analyses were performed to compare the downward trend of axillary lymph node dissection (ALND) in Korean cohort with that previously reported in a Dutch cohort. RESULTS: From KBCR data, 7478 patients met the inclusion criteria. The proportion of ALND significantly decreased from 2011 (76.6%) to 2018 (47.5%). Multivariate analysis revealed that earlier years at diagnosis, larger tumor size, and lymphatic invasion were associated with a higher odds ratio of performing ALND. Compared to the Dutch cohort, the downward trend of ALND in Korea was significantly more gradual (annual percent change: 37.2 vs. 5.8%, p < 0.001). CONCLUSIONS: This study demonstrated a downward trend of ALND in Korean patients with breast cancer. However, the rate of decrease was significantly slower than that in the Dutch cohort.

Favorable Impact of a Multidisciplinary Team Approach on Heart Transplantation Outcomes in a Mid-Volume Center.

Although a multidisciplinary team (MDT) approach is recommended for advanced heart failure and heart transplantation (HTx), no studies have investigated the impact of the team approach on post-HTx survival. Thus, we implemented an MDT approach in our HTx program in 2014, with the active involvement of critical care and extracorporeal life support (ECLS) teams and the use of a real-time online information sharing system. We hypothesized that this MDT approach would result in improved survival of patients who had undergone HTx. We enrolled 250 adult patients who underwent HTx between December 2003 and June 2018. They were divided into non-MDT (n = 120; before 2014) and MDT (n = 130; since 2014) groups. The primary outcome was overall mortality. In terms of donor age, diabetes, dialysis, ECLS, and waiting time, the MDT group had more high-risk patients. The MDT approach was found to be an independent predictor of overall survival using a variety of multivariable analytic methods, including inverse probability of treatment weighting analysis. An HF team, a critical care team, and an ECLS team collaboration may improve survival following HTx. To improve the efficiency of the MDT approach, we recommend using a real-time online information sharing system.

Effects of textured food masticatory performance in older people with different dental conditions.

BACKGROUND: Physiological deterioration (aging, poor dental status, and reduced tongue pressure) makes chewing difficult. This study aimed to investigate the chewing patterns of older people with or without dentures, evaluate the textural and masticatory properties of texture-modified radish Kimchi, and investigate the correlation between dental status and tongue pressure. Additionally, differences in the subjective-objective concordance of texture-modified Kimchi were investigated using the preference test. METHODS: This study included 32 Korean women aged between 65 and 85 years. Masticatory behavior was recorded by electromyography, and tongue pressure was measured using the Iowa Oral Performance Instrument. A preference test, with hardness as the relevant textural property, determined the participants' preferences among the test samples (food with a homogeneous structure-radish Kimchi). To assess preference differences, a questionnaire suitable for older people was designed. The preference for cooked radish Kimchi with various blanching times based on overall acceptability and self-reporting of preference was investigated to develop elderly-friendly food. The subjective scores indicated whether the sample (radish Kimchi) was hard or soft based on the chewing ability of the participants. Dental status, muscle activities, and tongue pressure were considered for the food design with optimized texture. The relationship between subject score and mastication properties were examined using multiple regression analysis. RESULTS: The number of chews and chewing time increased with hardness, significantly activating the masseter and temporalis muscles. The evaluation of masseter muscle activity, particularly for level-6 radish Kimchi, showed that older people with complete dentures chewed less actively than those with natural teeth (p < 0.05). The older people with natural teeth (18.94 ± 10.27 kPa) exhibited higher tongue pressure than those with complete dentures (10.81 ± 62.93 kPa), and the difference was statistically significant (p < 0.01). Older people preferred food with familiar tastes and textures. An association was found between the subjective hardness score and the objective hardness level. The perceived hardness intensity was linked to the chewing ability of the participant. Denture wearers exhibited a lower chewing ability, and at level 6, they perceived greater hardness of food than those with natural teeth. CONCLUSIONS: Developing food with a modified texture can bridge the gap between physiological and psychological aspects of food texture; texture-modified radish Kimchi, with limited blanching time, may be favorable for older people.

Navigation-assisted suture anchor insertion for arthroscopic rotator cuff repair.

BACKGROUND: Suture anchor placement for subscapularis repair is challenging. Determining the exact location and optimum angle relative to the subscapularis tendon direction is difficult because of the mismatch between a distorted arthroscopic view and the actual anatomy of the footprint. This study aimed to compare the reliability and reproducibility of the navigation-assisted anchoring technique with conventional arthroscopic anchor fixation. METHODS: Arthroscopic shoulder models were tested by five surgeons. The conventional and navigation-assisted methods of suture anchoring in the subscapularis footprint on the humeral head were tested by each surgeon seven times. Angular results and anchor locations were measured and compared using the Wilcoxon signed rank test. Interobserver intraclass correlation coefficients (ICCs) were analyzed among the surgeons. RESULTS: The mean angular errors of the targeted anchor fixation guide without and with navigation were 17° and 2° (p < 0.05), respectively, and the translational errors were 15 and 3 mm (p < 0.05), respectively. All participants showed a narrow range of anchor fixation angular and translational errors from the original target. Among the surgeons, the interobserver reliabilities of angular errors for ICCs of the navigation-assisted and conventional methods were 0.897 and 0.586, respectively, and the interobserver ICC reliabilities for translational error were 0.938 and 0.619, respectively. CONCLUSIONS: The navigation system may help surgeons be more aware of the surrounding anatomy and location, providing better guidance for anchor orientation, including footprint location and anchor angle.

Arthroscopic bare spot method underestimates true bone defect in bony Bankart lesion.

INTRODUCTION: The need for precise quantification of the glenoid defect should be emphasized in the choice of surgery for bony Bankart lesion especially in its critical values of 16% to 25. The study aims to verify the validity of bare spot method for arthroscopic quantification of glenoid bone defect using several varieties of posterior portal location. MATERIALS AND METHODS: Two intact cadaveric glenoids were prepared for the study. The greatest anteroposterior diameter of the perfect circle concept of the glenoid is identified and center of the circle is marked as glenoid bare spot with metal marker. Sixteen percent and 25% defect were sequentially created using a saw at 0° axis parallel to the longitudinal axis of the glenoid. These were confirmed by 3D CT glenoid scan based on glenoid rim distances. Each glenoids were mounted on Sawbone dome holder model simulating neutral version. Quantification of Glenoid bone defects were sequentially measured by glenoid bare spot method arthroscopically by 5 shoulder arthroscopy trained surgeons in 5 varieties of posterior portals in 5 cycles. Paired sample t test was done for arthroscopic over CT scan method of glenoid bone loss quantification. One way ANOVA for portal location analysis was done. RESULTS: Glenoid bare spot method significantly underestimates 16% and 25% glenoid bone defect to 9% ± 2 (P < 0.001) and 18% ± 2 (P < 0.001), respectively, compared to 3D CT scan method. There was good intra-class correlation coefficient of 0.97 for inter-rater reliability. There was no significant difference in quantification in between five portal sites by one-way ANOVA (P > 0.05). CONCLUSIONS: Arthroscopic glenoid bare spot method using the anterior viewing portal significantly underestimates glenoid bone loss in critical margin degrees of decision making in shoulder instability surgery. Minimal variation of posterior portal location for the calibrated probe does not cause significant difference in Glenoid bone loss quantification.

Improvement of arthroscopic surgical performance using a new wide-angle arthroscope in the surgical training.

BACKGROUND: We have developed a new arthroscope with a field of view of 150°. This arthroscope requires less motion to maneuver and exhibits reduced optical error. It also improves how novices learn arthroscopy. We hypothesized that the surgical performance with this arthroscope is superior to that with a conventional arthroscope. This study tested the hypothesis by using motion analysis and a new validated parameter, "dimensionless squared jerk" (DSJ). METHODS: We compared the surgical performance between the use of the wide-angle arthroscope and that of the conventional arthroscope among 14 novice orthopedic residents who performed 3 standardized tasks 3 times with each arthroscope. The tasks simulated the surgical skills in arthroscopic rotator cuff repair. The arthroscope motion was analyzed using an optical tracking system. The differences in performance parameters, such as the time taken to complete the tasks, average acceleration of the hands (m/s2), number of movements, and total path length (m) including DSJ between the 2 arthroscopes were investigated using paired t-tests. RESULTS: All estimated values for the tasks using the 150° arthroscope were lower than those for the tasks using the 105° arthroscope. Statistically significant differences in performance between the 2 arthroscopes were observed only for DSJ (p = 0.014) and average acceleration (p = 0.039). CONCLUSIONS: DSJ and average acceleration are reliable parameters for representing hand-eye coordination. The surgical performance of novice arthroscopists was better with the new wide-angle arthroscope than with the conventional arthroscope.

Comparison of the biomechanics of radial head prostheses with dynamic loading in the radiocapitellar joint.

We used eight fresh cadaveric elbows to evaluate the biomechanical characteristics of the native radial head, an anatomic radial head prosthesis, and a non-anatomic radial head prosthesis using a dynamic model. The biceps, brachialis, and triceps were attached to pneumatic actuators loaded to mimic muscle force. The radiocapitellar contact pressure and area were measured in real time, and the associated curves were depicted simultaneously. No significant differences in the contact area or associated curves were found between native radial head and the anatomic radial head prosthesis. The contact pressure and associated curve for the anatomic radial head prosthesis were better than those for the non-anatomic radial head prosthesis. We conclude from this study that the contact pressure and area of the elbow with anatomic radial head prosthesis are similar to those of the native radial head. The anatomic radial head prosthesis appears to be more suitable in clinical use.

Contact Mechanics of Anatomic Radial Head Prosthesis: Comparison Between Native Radial Head and Anatomic Radial Head Prostheses in the Dynamic Mode.

PURPOSE: The biomechanical characteristics of anatomic radial head prostheses have not been completely investigated. We compared and analyzed the contact kinematic characteristics of the native radial head and radial head prostheses replicating the native head contour, using a real-time flexion simulation model. METHODS: Ten fresh-frozen cadavers were used in this pilot study. A simulating dynamic motion mode from 0° to 130° of elbow flexion was applied. Radiocapitellar contact pressure and area were measured using a real-time digitized pressure sensor. Further, contact area and pressure curves were obtained during flexion, using a motion-tracking device. RESULTS: The mean contact area, mean contact pressure, and peak contact pressure of the native radial head and radial head prosthesis were 39 mm2, 0.0078 kgf/mm2, 0.0123 kgf/mm2, and 33 mm2, 0.0093 kgf/dm2, 0.0148 kgf/mm2, respectively. The contact area and pressure curves were parabolic nonlinear for the radial head prosthesis and more linear for the native radial head. CONCLUSIONS: The radial head prosthesis mimics the mechanics of the native radial head in terms of mean contact area, mean contact pressure, and peak contact pressure; however, different patterns of contact pressure and area curves during elbow flexion-extension were observed. CLINICAL RELEVANCE: We found that the biomechanics of the anatomic radial head prostheses used in the study were similar to those of the native radial head.

Graft tears after arthroscopic superior capsule reconstruction (ASCR): pattern of failure and its correlation with clinical outcome.

INTRODUCTION: Arthroscopic superior capsule reconstruction (ASCR) using fascia lata autograft is a new surgical technique developed to overcome irreparable rotator cuff tears. There is little information about graft tear after ASCR and its impact on clinical outcome. This study is to investigate the graft tear rate, pattern of failure, and its correlation with clinical outcomes after arthroscopic superior capsule reconstruction (ASCR). MATERIALS AND METHODS: From June 2013 to June 2016, 31 shoulders in 31 consecutive patients (mean 65.3 years) underwent ASCR using fascia lata autograft for irreparable large-to-massive tears. Magnetic resonance imaging (MRI) was performed before surgery and at mean 12.8 months (12-24 months) after surgery to assess fatty infiltration progression and graft integrity. Graft tear was defined as the loss of graft continuity and was categorized as medial and lateral rows according to the failure location. Acromiohumeral distance (AHD) was pre- and postoperatively measured with the standard radiograph. Pain visual analog scale (VAS) score, American Shoulder and Elbow Surgeons (ASES) score, constant score, and physical examination were used to assess clinical outcomes. Average follow-up was 15 months (range 12-24 months) after surgery. RESULTS: Mean active forward elevation increased from 133° to 146° (P = 0.011). Mean VAS score, ASES score, and constant score significantly improved: from 6 to 2.5, 54.4 to 73.7, and 51.7 to 63.7, respectively (P < 0.001). There was no remarkable progression of fatty infiltration after surgery. AHD increased from 5.3 mm preoperatively to 6.4 mm postoperatively (P < 0.016). Nine patients (29%) showed graft tear on follow-up MRI: 7 and 2 at the medial and lateral rows, respectively. Although the intact graft group showed better outcomes than the graft tear group (pain VAS score 2.3 vs. 3.0; ASES score 74.1 vs. 69.8; constant score 63.4 vs. 57.9), the results were not statistically significant. CONCLUSIONS: Graft tear rate after ASCR assessed by MRI was 29%, and failures mostly occurred at the medial row. The graft tear group showed clinical improvement despite the recurred superior capsule defect. LEVEL OF EVIDENCE: IV, case series, treatment study.

The Dimensionless Squared Jerk: An Objective Parameter That Improves Assessment of Hand Motion Analysis during Simulated Shoulder Arthroscopy.

PURPOSE: Attempts to quantify hand movements of surgeons during arthroscopic surgery faced limited progress beyond motion analysis of hands and/or instruments. Surrogate markers such as procedure time have been used. The dimensionless squared jerk (DSJ) is a measure of deliberate hand movements. This study tests the ability of DSJ to differentiate novice and expert surgeons (construct validity) whilst performing simulated arthroscopic shoulder surgical tasks. METHODS: Six residents (novice group) and six consultants (expert group) participated in this study. Participants performed three validated tasks sequentially under the same experimental setup (one performance). Each participant had ten performances assessed. Hand movements were recorded with optical tracking system. The DSJ, time taken, total path length, multiple measures of acceleration, and number of movements were recorded. RESULTS: There were significant differences between novices and experts when assessed using time, number of movements with average and minimal acceleration threshold, and DSJ. No significant differences were observed in maximum acceleration, total path length, and number of movements with 10m/s2 acceleration threshold. CONCLUSION: DSJ is an objective parameter that can differentiate novice and expert surgeons' simulated arthroscopic performances. We propose DSJ as an adjunct to more conventional parameters for arthroscopic surgery skills assessment.

Development of an end-effector device for loose body removal in hip arthroscopy.

This article describes a novel hand-operated end-effector device developed for loose body removal in hip arthroscopy. This sterilizable and reusable device incorporates a wire-ball joint mechanism that provides motion with 5 degrees of freedom. The design accounted for the following: (1) the diameter of the femoral head, (2) range of motion of the wrist joint of the operator, (3) ease of assembly of modular parts, and (4) material stiffness and durability. The developed device is composed of three parts: a pistol-shaped hand-held unit, forceps module, and end-effector module, all of which were constructed using polyamide-imide. Experiments were conducted to characterize the range of motion, pushing force, and lateral stiffness of the end-effector. Seven consulting surgeons evaluated the performance of the device in arthroscopic hip model and cadaveric studies in comparison with that of a conventional linear grasper. The experimental results show that the developed device can perform tasks that conventional linear graspers cannot. A specialized end-effector device was developed for hip arthroscopy where a high degree of stiffness is required. The end-effector module is interchangeable based on the required outer diameter, and it is also reusable after sterilization at high temperature.

Development and preclinical trials of a wire-driven end effector device for frozen shoulder treatment.

Several different flexible end effectors have been developed to solve the problem of approaching the lesion in a minimally invasive surgery. In this paper, we developed a wire-driven end effector device to treat frozen shoulder. Since the device is for capsular release surgery, it has a suitable bend radius for the surgery. It is a cylindrical cannula that can fit various surgical tools and can be sterilized after use. The end effector is made of an elastic material called PAI (polyamide-imide) with its outer diameter and total length being 4 and 19 mm. It is controlled by wires that are connected to a motor. Through quantitative evaluation, we confirmed that the end effector can bend up to 90° in an upward or downward direction. Through qualitative evaluation, we confirmed that the device can easier access all regions of the glenoid in a shoulder model than conventional electrocautery. An experiment on a cadaver followed, which allowed us to discuss the real life performance, operation, and areas of improvement of the device with surgeons. From the experiments, we confirmed that our target region, the IGHL (inferior glenohumeral ligament), is within the reach of our device. The surgeon also evaluated that the control of the device caused no inconvenience.

Beveled posteromedial corner of the radial head: a three-dimensional micro-computed tomography modeling study.

The posteromedial quadrant of the radial head is known to be different from the other quadrants. However, the explanation of this unique anatomical feature remains elusive. Hence, this study was designed to address this unique anatomical variance using three-dimensional µCT (micro-computed tomography) analysis. Nine fresh cadaveric radial heads were scanned using µCT. Three-dimensional subchondral bone and cartilage models were rendered. Both models were separated into the four quadrants at both the periphery (rim) and the articulating dish (fovea): anteromedial (AM), posteromedial (PM), posterolateral (PL), and anterolateral (AL). Each quadrant was analyzed in terms of (1) subchondral bone porosity (SBP), (2) mean subchondral bone thickness (MSBT), and (3) mean cartilage thickness (MCT). There was a significant difference between the fovea and the rim in terms of its microarchitectural features. Although within the fovea, the PM quadrant did not differ significantly from the other quadrants, a significant difference was found within the rim. In terms of SBP, PM, AM, PL and AL were calculated as 33, 37, 36 and 35%, respectively. In terms of MSBT, PM, AM, PL and AL were calculated as 0.11, 0.10, 0.09, and 0.09 mm, respectively. In terms of MCT, PM, AM, PL and AL were calculated 1.09, 0.81, 0.84 and 0.83 mm, respectively. The PM corner of the radial head between the 8 and 9 o'clock positions, was beveled. This might explain why the PM quadrant of the rim differed significantly from the other quadrants in terms of its microarchitectural features.

A hands-free region-of-interest selection interface for solo surgery with a wide-angle endoscope: preclinical proof of concept.

BACKGROUND: A hands-free region-of-interest (ROI) selection interface is proposed for solo surgery using a wide-angle endoscope. A wide-angle endoscope provides images with a larger field of view than a conventional endoscope. With an appropriate selection interface for a ROI, surgeons can also obtain a detailed local view as if they moved a conventional endoscope in a specific position and direction. METHODS: To manipulate the endoscope without releasing the surgical instrument in hand, a mini-camera is attached to the instrument, and the images taken by the attached camera are analyzed. When a surgeon moves the instrument, the instrument orientation is calculated by an image processing. Surgeons can select the ROI with this instrument movement after switching from 'task mode' to 'selection mode.' The accelerated KAZE algorithm is used to track the features of the camera images once the instrument is moved. Both the wide-angle and detailed local views are displayed simultaneously, and a surgeon can move the local view area by moving the mini-camera attached to the surgical instrument. RESULTS: Local view selection for a solo surgery was performed without releasing the instrument. The accuracy of camera pose estimation was not significantly different between camera resolutions, but it was significantly different between background camera images with different numbers of features (P < 0.01). The success rate of ROI selection diminished as the number of separated regions increased. However, separated regions up to 12 with a region size of 160 × 160 pixels were selected with no failure. Surgical tasks on a phantom model and a cadaver were attempted to verify the feasibility in a clinical environment. CONCLUSIONS: Hands-free endoscope manipulation without releasing the instruments in hand was achieved. The proposed method requires only a small, low-cost camera and an image processing. The technique enables surgeons to perform solo surgeries without a camera assistant.

Redisplacement of Distal Radius Fracture after Initial Closed Reduction: Analysis of Prognostic Factors.

BACKGROUND: To evaluate risk factors of redisplacement and remind surgeons of key factors regarding conservative treatment of distal radius fracture. METHODS: A total of 132 patients who received conservative treatment for distal radius fractures between March 2008 and February 2011 were included in this study. Radial inclination, radial length, volar tilting angle, ulnar variance, fragment translation, and presence of dorsal metaphyseal comminution were measured on the X-rays taken immediately after reduction, one week after injury during the first follow-up outpatient clinic visit, and after the gain of radiological union. Secondary displacement was defined as a loss of reduction during the follow-up period, and was divided into 'early' and 'late' categories. We analyzed the influence of initial displacement radiologic variables, dorsal cortex comminution, and patient age on the development of secondary displacement. RESULTS: Development of secondary displacement was significantly associated only with initial displacement radiologic variables (p < 0.001), development of the late secondary displacement was significantly associated with age (p = 0.005), and initial displacement radiologic variables were associated significantly with a serial increase in ulnar variance (p = 0.003). CONCLUSIONS: Greater displacement on the initial radiographs indicates a higher possibility of development for secondary displacement, and older patients had a higher probability of late secondary displacement development. Furthermore, dorsal comminutions did not affect secondary displacement directly.

Comparison of results after anterior cruciate ligament reconstruction using a four-strand single semitendinosus or a semitendinosus and gracilis tendon.

PURPOSES: To compare the clinical and functional results of anterior cruciate ligament (ACL) reconstruction using an autologous four-strand single semitendinosus (ST) tendon or a ST and gracilis tendon. It was hypothesized that successful ACL reconstruction using a single ST tendon without the gracilis tendon could provide comparable knee stability and reduce donor site morbidity. METHODS: This study evaluated 144 cases of single-bundle ACL reconstruction using an autologous hamstring tendon. The ST group included 85 cases of reconstruction using a single ST tendon, and the ST/G group included 59 cases of reconstruction using a ST tendon and a gracilis tendon. An extracortical suspension device and a suture tied around a screw post with an additional bioabsorbable screw were used to fix the femoral and tibial tunnels, respectively. Clinical evaluations involved the Lachman, pivot-shift, and one-leg hop tests; an isokinetic test; a KT-2000 arthrometer; an assessment of return to pre-injury activities; and Lysholm, Tegner activity, and International Knee Documentation Committee (IKDC) subjective scores. RESULTS: No significant differences were found between the ST and ST/G groups with respect to the Lysholm, Tegner activity, and subjective IKDC scores; the Lachman, pivot-shift, and one-leg hop tests; KT-2000 arthrometer side-to-side differences; or return to pre-injury activities. However, mean peak torque deficit, as determined using the isokinetic test during flexion at 60°/s, was significantly lower in the ST group than in the ST/G group (p = 0.047). CONCLUSION: This study showed good results for ACL reconstruction using a single ST tendon without deterioration of stability. This provides the evidence that ACL reconstruction using a single ST tendon without the gracilis tendon decreases donor site morbidity without compromising joint stability. LEVEL OF EVIDENCE: IV.