Is a Novel Fluoroscopic Intraoperative Reference System Superior to Conventional Management for Distal Radius Fracture Reduction? A Propensity-matched Comparative Study.

BACKGROUND: Preoperative planning is generally performed to simulate the process of reduction as well as to determine the size and placement of implants in patients undergoing distal radius fracture surgery. We previously described a three-dimensional (3D) digital preoperative planning system for the osteosynthesis of distal radius fractures, and we have developed a novel intraoperative referencing system that superimposes preoperative planning (such as plate position and length) onto fluoroscopic images during surgery; however, its efficacy has not been evaluated compared with conventional planning and surgery. QUESTIONS/PURPOSES: Does use of a novel intraoperative referencing system result in (1) better Mayo wrist scores at 3 and 6 months after surgery and (2) less loss of reduction in terms of ulnar variance, palmar tilt, and radial inclination on plain radiographs taken 1 week, 3 months, and 6 months after surgery compared with conventional preoperative planning? METHODS: Between April 2014 and October 2021, we treated 294 patients with open reduction and volar plate fixation for distal radius fractures. Of 294 patients, 65% (191) underwent surgery using either conventional preoperative planning or a novel intraoperative referencing system. The remaining patients were excluded because they were younger than 18 years, they had some missing medical records related to the clinical outcomes, or they had a previous history of upper extremity injuries. During that time, we generally treated fractures with volar plates when there was: more than 2 mm of stepoff/gap in the articular surface, a dorsal tilt more than 15°, radial inclination less than 15°, or radial shortening more than 5 mm. Generally, we used a flexor carpi radialis approach. In some patients who had dorsal fragments, we added a dorsal approach. At that time, we were developing the new intraoperative referencing system, so it was not used consistently. To arrive at a fair assessment, we opted to perform propensity matching based on age, gender, and AO fracture type. During the period in question, 36% (69 of 191) of patients with distal radius fractures who received a volar plate were treated using our novel intraoperative referencing system, and 64% (122 of 191) had surgery using conventional preoperative planning (control group). Of those, 91% (63 of 69) of patients who were treated with the intraoperative referencing system and 89% (108 of 122) of those in the control group were available for follow-up with all imaging and Mayo wrist scores at least 6 months after surgery. After propensity matching, that left us with two groups of 39 patients, who were well matched in terms of age and fracture type; these were the study groups. We also tried to match them according to gender, but there were fewer patients in the intraoperative referencing group, and the percentage of women for each group differed: 70% (44 of 63) in the intraoperative referencing group and 76% (82 of 108) in the control group. Also, there were fewer men with C3 fractures in the control group. Therefore, 64% (25 of 39) of patients in the intraoperative referencing group were women and 77% (30 of 39) of patients in the control group were women. In the intraoperative referencing group, our novel intraoperative referencing system was used in combination with the 3D digital preoperative planning system for preoperative planning. In the control group, preoperative planning was performed manually in a conventional manner using tracing paper and implant templates or using a digital template. We compared the groups in terms of operative duration, the radiation dose used in surgery, and Mayo wrist scores at 3 and 6 months after surgery. We also compared the groups in terms of loss of reduction on ulnar variance, palmar tilt, and radial inclination on plain radiographs taken 3 months and 6 months after surgery. We considered the plain radiograph taken 1 week after surgery as a baseline. Each item was compared between the image fusion and control groups using a Welch t - test. RESULTS: Mayo wrist scores were no different between the intraoperative referencing system and the control group at 3 months (71 ± 7 versus 72 ± 11, mean difference 1 [95% CI -3.7 to 5.7]; p = 0.07) or at 6 months after surgery (76 ± 6 versus 79 ± 11, mean difference 3 [95% CI -3.5 to 7.9]; p = 0.12). There were no differences in surgical duration or radiation doses between the intraoperative referencing and control groups. We found only a small advantage in favor of the intraoperative referencing system in terms of loss of reduction on ulnar variance (3 months after surgery: 0.2 ± 0.4 mm versus 0.6 ± 0.7 mm, mean difference 0.4 mm [95% CI 0.15 to 0.69]; p = 0.003, 6 months after surgery: 0.4 ± 0.6 mm versus 0.8 ± 0.8 mm, mean difference 0.4 mm [95% CI 0.05 to 0.73]; p = 0.02 for the intraoperative referencing system and the control group, respectively). This difference in radial shortening was so small that it was not likely to have been clinically important. CONCLUSION: We found no clinically important advantages from the use of our novel intraoperative referencing system except a slight improvement in ulnar variance. Therefore, we recommend against its use in everyday practice at this time. However, future improvements may lead to better clinical outcomes, so we plan further investigations. LEVEL OF EVIDENCE: Level III, therapeutic study.

Magnetic resonance imaging predicts outcomes of conservative treatment in patients with lateral epicondylitis.

BACKGROUND: The clinical validity of positive magnetic resonance imaging findings in lateral epicondylitis is controversial. We hypothesized that magnetic resonance imaging could predict the outcome of conservative treatment. This study determined the relationship between magnetic resonance imaging-defined disease severity and treatment outcomes in patients with lateral epicondylitis. METHODS: This retrospective single-cohort study included 43 conservatively managed and 50 surgically treated patients with lateral epicondylitis. The magnetic resonance imaging scores and clinical outcomes were examined six months post-treatment, and the former was compared between patients with good and poor treatment outcomes. We developed operating characteristic curves of magnetic resonance imaging scores for treatment outcomes, and divided patients into magnetic resonance imaging-mild and severe groups according to the obtained cut-off value of the scores. We compared the outcomes of conservative treatment with that of surgery for each magnetic resonance imaging severity. RESULTS: Twenty-nine (67.4%) conservatively treated patients had good outcomes, while 14 (32.6%) had poor outcomes. The magnetic resonance imaging score was higher in patients with poor outcomes; the cut-off value was 6. Forty-three (86.0%) surgically treated patients had good outcomes, while 7 (14.0%) had poor outcomes. There was no significant difference in magnetic resonance imaging scores between patients with good and poor surgical outcomes. In the magnetic resonance imaging-mild group (score ≤ 5), the outcome showed no significant difference between the conservative and surgical treatment groups. In the magnetic resonance imaging-severe group (score≥6), the outcome of conservative treatment was significantly worse than that of surgical treatment. CONCLUSIONS: The magnetic resonance imaging score was associated with conservative treatment outcomes. A treatment strategy that includes surgery should be considered for patients with severe magnetic resonance imaging findings; this is not recommended for those with mild magnetic resonance imaging findings. Magnetic resonance imaging is helpful in determining the best treatment strategies for patients with lateral epicondylitis. LEVEL OF EVIDENCE: III, Retrospective cohort study.

Improving visualization of the articular cartilage of the knee with magnetic resonance imaging under axial traction: a comparative study of different traction weights.

OBJECTIVE: Lesions of the articular cartilage of the knee, especially early grades, are not always accurately detected by magnetic resonance imaging (MRI) because of contact between the articular cartilage surfaces of the femur and the tibia. This study aimed to assess the effects of axial leg traction during knee MRI examination on joint space widening and articular cartilage visualization and evaluate the ideal weight for traction. METHODS: MRI was performed on ten healthy volunteers using a 3-T MRI unit with a 3D dual-echo steady-state gradient-recalled echo sequence. Conventional MRI was performed first, followed by traction MRI. The traction weight increased in the order of 5 kg, 10 kg, and 15 kg. Joint space widths were measured, and articular cartilage visualization was assessed at the medial and lateral tibiofemoral joints. Volunteers were asked to evaluate pain and discomfort using a visual analog scale during each procedure with axial traction to assess the safety of traction MRI. RESULTS: The medial tibiofemoral joint space width significantly increased, and the visualization of the articular cartilage significantly improved by applying traction. The joint space width and the articular cartilage visualization showed no significant differences among traction weights of 5 kg, 10 kg, and 15 kg. Pain and discomfort during traction MRI examination were lowest with a traction weight of 5 kg. CONCLUSION: Traction MRI examination may be useful in evaluating articular cartilage lesions at the medial tibiofemoral joint. A traction weight of 5 kg may be sufficient with minimum pain and discomfort.

A novel three-dimensional MRI-CT image fusion technique for precise preoperative evaluation and treatment of capitellar osteochondritis dissecans.

OBJECTIVES: We developed a novel method to create three-dimensional magnetic resonance imaging-CT (3D MRI-CT) fusion images for detailed lesion evaluation and surgical simulation in capitellar osteochondritis dissecans (COCD). This study aimed to clarify its usefulness. METHODS: We enrolled 12 boys with COCD (mean age, 13.8 years) and preoperatively constructed 3D models of the humerus and articular cartilage from MR images obtained with a 3-T imager. For better visualization of the articular cartilage outline, we applied 7 kg of axial traction to the elbow during MRI. We also constructed a 3D model of the humerus from CT images. 3D MRI-CT fusion images were created using both models. The average distance difference between two corresponding points as per the 3D CT and 3D MRI models of the humerus was evaluated. Using the 3D MRI-CT fusion images, we measured longitudinal and transverse lesion diameters; evaluated articular cartilage fissures and defects, articular surface deformities, and the International Cartilage Repair Society (ICRS) classification; and validated the results using intraoperative findings. RESULTS: The mean average distance difference was 0.75 mm. The 3D MRI-CT fusion images accurately reproduced lesion conditions in every case and correctly predicted the ICRS classification with 100% accuracy. Preoperatively measured longitudinal and transverse lesion diameters were not significantly different from intraoperative measurements (p = 0.79, 0.32 respectively). CONCLUSION: 3D MRI-CT fusion images provide a detailed evaluation of COCD lesion severity by presenting the exact positional relationship between the articular cartilage and subchondral bone. KEY POINTS: • We developed a novel method to create three-dimensional magnetic resonance imaging-computed tomography (3D MRI-CT) fusion images for the evaluation of capitellar osteochondritis dissecans. • 3D MRI-CT fusion images enabled the accurate prediction of lesions and provided a detailed evaluation of lesion severity by presenting the exact positional relationship between the articular cartilage and subchondral bone.

Injury-Induced HSP27 Expression in Peripheral Nervous Tissue Is Not Associated with Any Alteration in Axonal Outgrowth after Immediate or Delayed Nerve Repair.

We investigated injury-induced heat shock protein 27 (HSP27) expression and its association to axonal outgrowth after injury and different nerve repair models in healthy Wistar and diabetic Goto-Kakizaki rats. By immunohistochemistry, expression of HSP27 in sciatic nerves and DRG and axonal outgrowth (neurofilaments) in sciatic nerves were analyzed after no, immediate, and delayed (7-day delay) nerve repairs (7- or 14-day follow-up). An increased HSP27 expression in nerves and in DRG at the uninjured side was associated with diabetes. HSP27 expression in nerves and in DRG increased substantially after the nerve injuries, being higher at the site where axons and Schwann cells interacted. Regression analysis indicated a positive influence of immediate nerve repair compared to an unrepaired injury, but a shortly delayed nerve repair had no impact on axonal outgrowth. Diabetes was associated with a decreased axonal outgrowth. The increased expression of HSP27 in sciatic nerve and DRG did not influence axonal outgrowth. Injured sciatic nerves should appropriately be repaired in healthy and diabetic rats, but a short delay does not influence axonal outgrowth. HSP27 expression in sciatic nerve or DRG, despite an increase after nerve injury with or without a repair, is not associated with any alteration in axonal outgrowth.

Effect of elbow MRI with axial traction on articular cartilage visibility-a feasibility study.

OBJECTIVE: Accurate evaluation of the articular cartilage of the elbow using MRI is sometimes challenging because of its anatomical complexity and relatively small size. Moreover, the articular cartilage of the humerus is in close contact with the opposing cartilage surfaces. Magnetic resonance arthrography with traction was reported to resolve this issue; however, less invasive methods are desirable. This study aimed to assess the effect of MRI with axial traction (without arthrography) on joint space widening and cartilage outline visibility of the elbow. MATERIALS AND METHODS: We enrolled 10 volunteers (female = 1; mean age, 36.7 ± 8.6; range 28-56) and performed MRI with and without axial traction on the elbow. Joint space widths were measured, and the humeral articular cartilage outline visibility was evaluated at the radiocapitellar joint and lateral one-third and medial one-third of the ulnohumeral joints. Measurements were compared using the Wilcoxon signed-rank test. Significance was set at p < 0.05. Volunteers scored pain and discomfort during MRI with traction using the visual analog scale in a questionnaire format. RESULTS: Traction significantly increased joint space width at the radiocapitellar joint. Humeral articular cartilage outline visibility also significantly improved at the radiocapitellar joint. Pain and discomfort scores during traction MRI were low. CONCLUSION: MRI of the elbow with traction widens joint space and enables better articular cartilage visibility at the radiocapitellar joint. Anatomical features of the elbow might have affected these results. Therefore, it would be safe and useful for evaluating elbow injuries involving articular cartilage lesions.

Optimization of Traction Magnetic Resonance Imaging to Improve Visibility of the Elbow Cartilage.

We previously reported that elbow magnetic resonance imaging (MRI) with 7 kg traction increases the joint space width of the radiocapitellar joint and improves articular cartilage visibility without arthrography. However, the optimal traction weight remains unclear. We assessed the effects of different traction weights on elbow MRI in 30 healthy volunteers. Elbow MRI was performed without traction and with 3, 5, and 7 kg axial tractions. The joint space width, humeral articular cartilage outline visibility, and intraprocedural pain/discomfort were evaluated. The joint and cartilage parameters were measured at the radiocapitellar joint and the lateral and medial thirds of the ulnohumeral joint. At the radiocapitellar joint, the joint space width increased significantly with traction. The cartilage outline visibility significantly increased with traction, with no significant differences among the traction weights. No significant result was observed at the lateral and medial thirds of the ulnohumeral joint. Pain and discomfort significantly increased as we used heavier traction weights. Elbow MRI with 3 kg traction showed sufficient effects similar to those observed with 7 kg traction with minimal pain and discomfort. There was no difference in the effect of traction between male and female participants. This procedure may enable enhanced visualization of intra-articular elbow injuries.

Three-Dimensional Morphometric Analysis of the Volar Cortical Shape of the Lunate Facet of the Distal Radius.

In cases of distal radius fractures, the fixation of the volar lunate facet fragment is crucial for preventing volar subluxation of the carpal bones. This study aims to clarify the sex differences in the volar morphology of the lunate facet of the distal radius and its relationship with the transverse diameter of the distal radius. Sixty-four CT scans of healthy wrists (30 males and 34 females) were evaluated. Three-dimensional (3D) images of the distal radius were reconstructed from the CT data. We defined reference point 1 as the starting point of the inclination toward the distal volar edge, reference point 2 as the volar edge of the joint on the bone axis, and reference point 3 as the volar edge of the distal radius lunate facet. From the 3D coordinates of reference points 1 to 3, the bone axis distance, volar-dorsal distance, radial-ulnar distance, 3D straight-line distance, and inclination angle were measured. The transverse diameter of the radius was measured, and its correlations with the parameters were evaluated. It was found that in males, compared to females, the transverse diameter of the radius is larger and the protrusion of the volar lunate facet is greater. This suggests that the inclination of the volar surface is steeper in males and that the volar locking plate may not fit properly with the volar cortical bone of the lunate facet, necessitating additional fixation.

Pathophysiology of sex difference in refractoriness in lateral epicondylitis: Biomechanical study of wrist torque.

Eccentric contractions of the wrist extensors worsen lateral epicondylitis (LE), whose pathophysiology may involve sex differences in wrist torque. This study aimed to investigate sex differences in wrist torque in patients with LE. The wrist extension and flexion torques of 22 patients with LE (11 males and 11 females) were measured. Maximum muscle output over time was measured for 20 s, initial torque was defined as muscle strength, and the degree of eccentric contraction was quantified and defined as the eccentric contraction index (ECI). The affected/unaffected side ratio of the wrist extensor, extensor/flexor ratio of muscle strength, and affected/unaffected side difference of ECI between sexes were statistically analyzed. Furthermore, correlations between wrist extensor torque, ECI, and Visual Analog Scale of pain during the examination were evaluated. Females were found to display lower affected/unaffected side ratios of the wrist extensor and wrist extension/flexion ratios for the affected side, compared with males; however, no differences were found in the wrist extension/flexion ratios for the unaffected side in both sexes. Additionally, females presented with larger differences between the affected and unaffected sides in the ECI. Based on correlations between wrist torques, ECI, and pain, females tended to suppress muscle output to prevent pain from eccentric contraction of wrist extensors more than males, which would induce an imbalance in muscle strength of the wrist extensors and flexors. This imbalance may result in chronic eccentric contraction of the wrist extensors with gripping, exacerbating LE.

The Effect of Axial Traction MRI on the Articular Cartilage Visibility in Thumb Carpometacarpal Arthritis.

OBJECTIVES: Thumb carpometacarpal arthritis has a high incidence. However, the degree of damage to the cartilage has not been accurately assessed. The purpose of this study was to examine the effects of axial traction of the thumb carpometacarpal joint during magnetic resonance imaging (MRI) on the visibility of articular cartilage in patients with thumb carpometacarpal arthritis and to evaluate the articular cartilage defect using MRI findings. MATERIALS AND METHODS: Forty-four patients with thumb carpometacarpal arthritis (14 males, 30 females) and a mean age of 67.3±8.6 years were classified according to Eaton Stages 1, 2, 3, and 4 in 2, 14, 24, and 4 patients, respectively. Axial traction MRI was performed with and without traction (3 kg) using 3-Tesla MRI (Siemens Magnetom Skyra) with a 3D T2* multiecho data imaging combination. The effectiveness of traction was verified using the joint space width before and after traction at five points (central, volar, dorsal, radial, and ulnar margins) and the original articular cartilage outline visibility classification (poor, intermediate, complete). The rate of remaining cartilage on each joint surface was also evaluated. Statistical significance was set at p<0.05 in this study. RESULTS: Joint space width increased significantly at all points with traction (P<0.01). The grade of articular cartilage outline visibility significantly improved from seven intermediate and 37 poor cases to 15 complete, 23 intermediate, and six poor cases (P<0.01). Significantly more articular cartilage remained in Stages 1-2 compared with Stages 3-4 arthritis of both articular surfaces (P<0.01 in first metacarpal, P=0.01 in trapezium). CONCLUSION: Axial traction of the thumb increased the joint space width and improved articular cartilage visibility in the thumb carpometacarpal joint. Our results suggested that axial traction MRI can be used for noninvasive evaluation of articular cartilage defects in patients with thumb carpometacarpal arthritis and aid in selecting the optimal surgical procedure.

An isolated rupture of the flexor digitorum tendon of the index finger following volar locking plate fixation of a distal radius fracture: A case report.

Volar locking plates (VLP) have been widely used recently to treat distal radius fractures and are considered the gold standard. One of the most common complications of distal radius fracture surgery is flexor pollicis longus rupture, which may also occur in other tendons. Here, we report a case of isolated rupture of the flexor digitorum profundus to the index finger after VLP fixation of a distal radial fracture. Only a few cases of this have been reported in the literature. In previously reported cases, the cause of tendon rupture was repetitive mechanical stress due to implant protrusion. In our case, the plate was placed too distally; however, soft tissue completely covered the distal part of the plate. There was obvious synovitis within the carpal tunnel; therefore, pressure within the carpal tunnel may have increased. The cause of rupture in our case was thought to be a combination of direct mechanical stress and poor circulation due to inadequate VLP fixation.

Sex differences in wrist torque and endurance-Biomechanical factors associated with developing lateral epicondylitis of the humerus.

Since eccentric contractions contribute to the development of tendinopathy, sex differences in wrist torque and endurance may be involved in the pathophysiology of lateral epicondylitis and its refractoriness. Therefore, the present study investigated sex differences in wrist torque and endurance. The wrist extension and flexion torques of the 100 wrists of 25 males and 25 females were measured. The following parameters were assessed: muscle strength at the starting- and end point for the measurement, Δ muscle strength, that is, the amount of a loss over time, and the muscle endurance ratio, that is, the decrease rate over time. Each parameter in males and females was statistically analyzed. In wrist extension, muscle strength at the starting point was 6.1 Nm for males and 3.3 Nm for females (p < 0.001); Δ Muscle strength was -0.052 Nm/s for males and -0.038 Nm/s for females (p = 0.036); The muscle endurance ratio was 99.1%/s for males and 98.8%/s for females (p = 0.015). In wrist flexion, muscle strength at the starting point and absolute value of Δ muscle strength were significantly larger in males than in females; No significant difference was observed in the muscle endurance ratio in wrist flexion between males and females. These results revealed sex differences in wrist torque and endurance. The muscle endurance ratio of the wrist extensors was lower in females than in males, which suggests that females need to exert more effort to maintain the wrist extension position under resistance. This may predispose the wrist extensor muscles in females to eccentric contractions.

Correlations between 3D preoperative planning and postoperative reduction in the osteosynthesis of distal humeral fractures.

BACKGROUND: Three-dimensional preoperative planning has been applied to the osteosynthesis of distal humerus fractures. The present study investigated the correlations between 3D preoperative planning and postoperative reduction for the osteosynthesis of distal humerus fractures using 3D parameters. METHODS: Twenty-three elbows of 23 distal humerus fracture patients who underwent osteosynthesis with three-dimensional preoperative planning were evaluated. 3D images of the distal humerus were created after taking preoperative CT scans of the injured elbow. Fracture reduction, implant selection, and placement simulations were performed based on 3D images. Postoperative CT images were taken 1 month after surgery. Correlations were evaluated with preoperative plans and postoperative 3D images. The longitudinal axis and coordinates of the humerus were defined on the 3D images. The coronal angle (CA) was defined as the angle formed by the long axis and the line connecting the medial and lateral margins of the trochlea of the humerus on a coronal plane image. The sagittal angle (SA) was defined as the angle formed by the long axis and the line connecting the top of the lateral epicondyle and the center of the humeral capitellum on a sagittal plane image. The axial angle (AA) was defined as the angle between the sagittal plane and the line connecting the medial and lateral margins behind the trochlea of the humerus. The intraclass correlation coefficients (ICC) of each measurement value were assessed between preoperative planning and postoperative images. RESULTS: Preoperative planning and postoperative measurement values were CA: 85.6 ± 5.9°/85.8 ± 5.9°, SA: 140.9 ± 8.5°/139.4 ± 7.9°, and AA: 84.0 ± 3.1°/82.6 ± 4.9°, respectively. ICCs were CA: 0.75 (P < 0.01), SA: 0.78 (P < 0.01), and AA: 0.34 (P < 0.05), respectively. CONCLUSIONS: The 3D preoperative planning of distal humeral fractures achieved the good correlations of coronal and sagittal angles, but the relatively poor correlation of the axial angle. This may be attributed to an inability to assess the rotation angle during surgery. We propose the measurement indices shown in the present study as a three-dimensional evaluation index for distal humerus fractures. TRIAL REGISTRATION: Registered as NCT04349319 at ClinicalTrials.gov.

Potential Relationships between the Median Nerve Cross-Sectional Area and Physical Characteristics in Unilateral Symptomatic Carpal Tunnel Syndrome Patients.

BACKGROUND: The present study investigated the relationships between the median nerve cross-sectional area (CSA) and physical characteristics in patients with unilateral symptomatic carpal tunnel syndrome (CTS). METHODS: Height, weight, body mass index (BMI), disease duration, results of electrodiagnostic testing (EDX), and median nerve CSA at the level of the wrist crease were recorded in 81 patients with CTS who presented with symptoms on only one side. Correlation coefficients between median nerve CSA and physical characteristics, disease duration, and results of EDX were analyzed. RESULTS: Median nerve CSA at the wrist crease (mm2) was significantly larger on the symptomatic side (14.1 ± 3.8) than on the asymptomatic side (11.5 ± 2.9). Median nerve CSA correlated with body weight (correlation coefficient = 0.39) and BMI (correlation coefficient = 0.44) on the asymptomatic side, but not on the symptomatic side. These correlations were slightly stronger in females (correlation coefficient = 0.46) than in males (correlation coefficient = 0.40). No correlations between median nerve CSA and disease duration and the results of EDX were observed in both sides. CONCLUSIONS: In patients with unilateral symptomatic CTS, median nerve CSA correlated with BMI only on the asymptomatic side. The present results suggest that the relationship between median nerve CSA and BMI in CTS is significant until symptom onset but may be masked by edema and pseudoneuroma after its onset. A higher BMI is associated with a larger CSA of the median nerve, which may be a risk factor for the development of CTS.

Advances in Bone Joint Imaging-Metal Artifact Reduction.

Numerous types of metal implants have been introduced in orthopedic surgery and are used in everyday practice. To precisely evaluate the postoperative condition of arthroplasty or trauma surgery, periprosthetic infection, and the loosening of implants, it is important to reduce artifacts induced by metal implants. In this review, we focused on technical advances in metal artifact reduction using digital tomosynthesis, computed tomography, and magnetic resonance imaging. We discussed new developments in diagnostic imaging methods and the continuous introduction of novel technologies to reduce metal artifacts; however, these innovations have not yet completely removed metal artifacts. Different algorithms need to be selected depending on the size, shape, material and implanted body parts of an implant. Future advances in metal artifact reduction algorithms and techniques and the development of new sequences may enable further reductions in metal artifacts even on original images taken previously. Moreover, the combination of different imaging modalities may contribute to further reductions in metal artifacts. Clinicians must constantly update their knowledge and work closely with radiologists to select the best diagnostic imaging method for each metal implant.

Analyzing Chronological Change in Postoperative Magnetic Resonance Imaging Results in Patients With Kienböck's Disease by Using an Original Grading System.

Background and objective Signal changes in MRI for Kienböck's disease have only been qualitatively assessed so far. In light of this, we proposed a new grading system for quantitative analysis with an ordinal scale. Methods The study included 31 patients (17 men, 14 women) with Kienböck's disease. By referring to Nakamura's MRI grading system, we devised a grading system with five grades (Grades 1-5) using proton density-weighted (PDW) coronal images with respect to the signal intensity of the lunate. All cases were examined by using the MRI grading system by three hand surgeons, both preoperatively and postoperatively. We evaluated the inter-rater reliability of our grading system by using the interclass correlation coefficient. After surgery, we implemented annual MRI evaluation for as long as possible and quantitatively assessed changes in MRI grades. We also investigated the correlation between postoperative MRI grades, Mayo Wrist Scores (MWS), and age at the surgery by using Pearson's coefficient. Results The MRI evaluation was performed 2-15 years after surgery. The reliability of our grading system was high; inter-rater interclass correlation coefficients were 0.783 (examiners 1-2), 0.780 (examiners 1-3), and 0.825 (examiners 2-3), representing a substantial agreement. The correlation coefficient between the MRI grade and MWS was -0.31, suggesting a mild negative correlation; postoperative MRI grade also correlated with age at surgery (Pearson's coefficient: 0.447). Conclusions Our proposed MRI grading system has high reliability and could be used to assess the regeneration of a necrotic lunate for quantitative analysis on an ordinal scale. Improvements were observed one to four years postoperatively, demonstrating a mild correlation with the clinical results.

Individual Evaluation of the Common Extensor Tendon and Lateral Collateral Ligament Improves the Severity Diagnostic Accuracy of Magnetic Resonance Imaging for Lateral Epicondylitis.

The effectiveness of magnetic resonance imaging for diagnosing lateral epicondylitis severity is controversial. We aimed to verify whether individual evaluations of the common extensor tendon and lateral collateral ligament would improve the severity diagnostic accuracy of magnetic resonance imaging for lateral epicondylitis. We obtained coronal images of the lateral elbow in three groups: healthy, clinically mild, and clinically severe. We used our scoring system for evaluation using combined and individual methods. We developed the receiver operating characteristic curve for diagnosis using the scores of the healthy and mild groups and that for severity diagnosis using the scores of the mild and severe groups. The scores, in decreasing value, were those of the severe, mild, and healthy groups, with a significant difference in both methods. The curve for diagnosis showed an area under the curve of 0.85 for the combined evaluation and 0.89 for the individual evaluation, without a significant difference between the methods (p = 0.23). The curve for severity diagnosis showed an area under the curve of 0.69 for combined and 0.81 for individual evaluation, with a significant difference between the methods (p = 0.046). Individual evaluation of the common extensor tendon and lateral collateral ligament improved the severity diagnostic accuracy of lateral epicondylitis.

Effects of Magnetic Resonance Imaging With Axial Traction of the Thumb Carpometacarpal Joint on Articular Cartilage Visibility: A Feasibility Study.

Objectives The objective of this study was to verify the usefulness of magnetic resonance imaging (MRI) with axial traction of the thumb for observing articular cartilage. Materials and methods Eleven healthy adult volunteers (39.7 ± 7.4 years) without thumb carpometacarpal joint arthritis or trauma were included in this study. A 3-tesla (3T) MRI (Magnetom Skyra, Siemens Healthineers AG, Munich, Germany) of the right thumb with axial traction applied by a finger trap with three traction weights (0, 2, and 5 kg) was performed. A 3D T2* multiecho data imaging combination (MEDIC) was selected to visualize the articular cartilage. After multiplanar reconstruction, sagittal and coronal images of the thumb carpometacarpal joint were used to evaluate the articular cartilage visibility and joint space widths at five locations. Articular cartilage visibility was evaluated using our original classification method that used the percentage of the cartilage detectable area. The Friedman test was used to compare the differences between each traction weight and location. Results Articular cartilage visibility significantly improved with axial traction. The average joint space widths with the 5-kg application were 1.9 ± 0.8, 3.9 ± 0.6, 2.0 ± 0.9, 3.9 ± 1.1, and 2.5 ± 1.4 mm at the center, volar edge, dorsal edge, radial edge, and ulnar edge, respectively. The joint space widths significantly increased proportionally with the traction weight at all locations. The joint space widths at the volar and radial edges were significantly greater than those at other locations. Conclusion Applying axial traction to the thumb increased the joint space widths and improved the visibility of the articular cartilage in the carpometacarpal joint on MRI.

Preoperative Evaluation and Surgical Simulation for Osteochondritis Dissecans of the Elbow Using Three-Dimensional MRI-CT Image Fusion Images.

We used our novel three-dimensional magnetic resonance imaging-computed tomography fusion images (3D MRI-CT fusion images; MCFIs) for detailed preoperative lesion evaluation and surgical simulation in osteochondritis dissecans (OCD) of the elbow. Herein, we introduce our procedure and report the findings of the assessment of its utility. We enrolled 16 men (mean age: 14.0 years) and performed preoperative MRI using 7 kg axial traction with a 3-Tesla imager and CT. Three-dimensional-MRI models of the humerus and articular cartilage and a 3D-CT model of the humerus were constructed. We created MCFIs using both models. We validated the findings obtained from the MCFIs and intraoperative findings using the following items: articular cartilage fissures and defects, articular surface deformities, vertical and horizontal lesion diameters, the International Cartilage Repair Society (ICRS) classification, and surgical procedures. The MCFIs accurately reproduced the lesions and correctly matched the ICRS classification in 93.5% of cases. Surgery was performed as simulated in all cases. Preoperatively measured lesion diameters exhibited no significant differences compared to the intraoperative measurements. MCFIs were useful in the evaluation of OCD lesions and detailed preoperative surgical simulation through accurate reproduction of 3D structural details of the lesions.

Trapezium Fracture Associated with Thumb Carpometacarpal Joint Dislocation: A Report of Three Cases and Literature Review.

Isolated trapezium fracture in combination with thumb carpometacarpal (CMC) joint dislocation is extremely rare, and no treatment consensus exists. Herein, we report 3 successfully treated cases of isolated trapezium fracture with thumb CMC joint dislocation. While good short-term results have been reported in the literature, the possibility of substantial ligament injuries that can lead to future instability of the thumb CMC joint must be noted. In order to obtain an excellent long-term clinical result, we propose the consideration of the anatomical repair of the CMC joint in terms of both bony and ligamentous structures in cases where instability remains after fracture fixation.