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Background Many researchers have questioned whether shoulder kinematics such as the glenohumeral position and scapular kinematics would be different in different age groups. However, studies comparing shoulder kinematics between different age groups have been rare. The aim of this study was to analyze and compare the three-dimensional (3D) glenohumeral position, scapular kinematics, and scapulohumeral rhythm (SHR) during scapular plane arm abduction between a normal young male group and a normal older male group. Methods Twenty normal men (10 young and 10 older) were enrolled in this controlled laboratory study. Fluoroscopic images were obtained using a single plane X-ray system. Bilateral computed tomography scans were taken to create a 3D model. A 3D-2D registration technique was used to determine the 3D position and orientation of the bones of the shoulder. Results During scapular plane arm abduction, there were significant differences in scapular kinematics between the groups. The older male group showed more upward rotation, posterior tilt, and external rotation than the young male group. On the other hand, the glenohumeral position such as superior inferior translation, anterior posterior translation, and external rotation of the humeral head did not show significant difference between the groups. The mean value of SHR for the overall arm elevation range from start to maximum elevation angle for the older group and young group was 2.298 ± 0.964 and 2.622 ± 0.931, respectively, showing a significant difference between the two groups (p = 0.035). Conclusions Scapular kinematics and SHR were significantly different between the older male group and the young male group. Our study could provide reference values of shoulder kinematics for older men aged 55-65 years.

The aim of this study was to compare the scapular kinematics and scapulohumeral rhythm of healthy participants during arm elevation and lowering and to find the difference between active motion and passive motion of the shoulder.The study examined the shoulders of 10 healthy men (mean age, 23.5 years; age range, 22-28 years). The shoulders of participants were elevated and lowered while fluoroscopic images were taken, and 3-dimensional bone models were created from 2-dimensional to 3-dimensional images using model registration techniques. The Euler angle sequences of the models' scapular kinematics and scapulohumeral rhythm were compared during active and passive shoulder motion.There was a significant statistical difference of upward rotation during arm elevation between active and passive shoulder movements (P = .027). In particular, the upward rotation between 45° and 90° of elevation showed a statistically significant difference (P.001). When the scapula was tilted posteriorly by active motion, it resulted in a statistically significant difference as there was more tilting in the high-degree range of motions than when it was tilted by passive motion (P.001). There was no statistically significant difference between the 2 groups in scapular external rotation. However, during arm lowering, scapular kinematics did not show statistically significant difference between active and passive motion.The scapular kinematics showed statistically significant differences between active and passive motion of upward rotation and posterior tilting of the scapula during arm elevation, but there were none during lowering. In terms of upward rotation, active shoulders rotated more upward during arm elevation.

Pelvic bone fractures are usually caused by high-energy trauma and are often accompanied by organ injuries. For hemodynamically unstable patients with pelvic bone fractures, knowing the anatomic type of fracture—whether it is a pelvic ring injury or an acetabular fracture—might be helpful in prioritizing treatment. A total of 302 patients with pelvic bone fractures who received treatment at the authors' level I trauma center between March 1, 2015, and February 28, 2017, were included in this study. Patients with pelvic bone fractures were enrolled in the Korea Trauma Data Bank and classified by anatomic type of pelvic bone fracture: pelvic ring injury, acetabular fracture, or combined fractures. The authors used t tests to analyze survival and death groups and multivariate regression to analyze mortality factors. Different types of pelvic bone fractures had significantly different mortality rates ( P P Orthopedics . 2021;44(6):e724–e728.]

The purpose of the present study was to estimate the risk of hip and spinal fracture after distal radius fracture. Data from the Korean National Health Insurance Service—National Sample Cohort were collected between 2002 and 2013. A total of 8013 distal radius fracture participants who were 50 years of age or older were selected. The distal radius fracture participants were matched for age, sex, income, region of residence, and past medical history in a 1:4 ratio with control participants. In the subgroup analysis, participants were stratified according to age group (50–59, 60–69, or ≥70 years) and sex (male or female). Distal radius fracture patients had a 1.51-fold and 1.40-fold higher incidence of hip fracture and spinal fracture in the adjusted models, respectively. Among males, patients of all ages had a significantly higher incidence of hip fracture, and those who were 50 to 69 years of age had a significantly higher incidence of spinal fracture. Among females, those older than 70 years had a significantly higher incidence of hip fracture, and patients of all ages had a significantly higher incidence of spinal fracture. Previous distal radius fracture has a significant impact on the risk of subsequent hip and spinal fractures.

This study aimed to compare the contact area, mean pressure, and peak pressure of the radiocapitellar joint (RCJ) in the upper limb after transradial amputation with those of the normal upper limb during elbow flexion and forearm rotation. Testing was performed using ten fresh-frozen upper limbs, and the transradial amputation was performed 5 cm proximal to the radial styloid process. The specimens were connected to a custom-designed apparatus for testing. A pressure sensor was inserted into the RCJ. The biomechanical indices of the RCJ were measured during elbow flexion and forearm rotation in all specimens. There was no significant difference in the contact area between the normal and transradial amputated upper limbs. However, in the upper limbs after transradial amputation, the mean pressure was higher than that in the normal upper limbs at all positions of elbow flexion and forearm rotation. The peak pressure was significantly higher in the upper limbs after transradial amputation than in the normal upper limbs, and was especially increased during pronation at 45° of elbow flexion. In conclusion, these results could cause cartilage erosion in the RCJ of transradial amputees. Thus, methods to reduce the pressure of the RCJ should be considered when a myoelectric prosthesis is developed.

The objective of this study was to investigate the clinical and radiologic outcomes after superior capsule reconstruction (SCR) with biceps tendon (BT) for irreparable rotator cuff tears.The retrospective study period was May 2015 through February 2018. The average follow-up was 32 months (24-48 months) after surgery. Study inclusion criteria included an arthroscopic SCR performed using only our technique and minimum 2-year clinical follow-up by office visit and survey. Exclusion criteria included irreparable subscapularis tear and those patients lost to follow-up. This method enabled SCR by using the extraarticular portion and the intraarticular portion and making it 2 to 3 bundles by moving back and forth in the intraarticular area. Physical examination and functional scoring procedures were performed before surgery and at 3, 6, 12, and 24 months after surgery. Radiography and magnetic resonance imaging (MRI) were performed before surgery, after surgery (only radiography), and at 6 and 24 months after surgery.Fifty-three shoulders involving 45 consecutive patients underwent BT technique for irreparable massive rotator cuff tears. The visual analog scale (VAS), American Shoulder and Elbow Surgeons (ASES), and constant score (CS) showed statistically significant improvement (VAS, 4.1-1.0; ASES, 60.9-82.7; and CS, 64.9-80.0; P.0001). The shoulder active range of motion improved significantly by 23 for forward elevation (125.3-148.4; P.0001) and by 12 for external rotation (38.0-50.9, P.0001). The acromiohumeral distance (AHD) was significantly increased by 2.7 mm (4.4 ± 1.4 mm -7.1 ± 1.3 mm). No graft tear was detected in 39 patients (86.7%) during follow-up (24-48 months).SCR via our technique improved clinical and radiologic outcomes. Thirty-five (77.7%) patients achieved 17-point improvement (the minimally clinically important difference) in the last follow-up of ASES score. Clinical scores and AHD had significantly increased, and good healed rate (86.7%) was observed in MRI.Level IV, retrospective case series.

Background The occurrence and related predictors of acromial fracture following reverse total shoulder arthroplasty (RTSA) have not been fully elucidated. The aim of this study was to determine the incidence and risk factors of acromial fractures after RTSA. Methods We conducted a multicenter, retrospective case-control study of 787 cases (29 in acromial fracture group and 758 in control group) that underwent RTSA performed by 6 surgeons. The mean duration of follow-up after RTSA was 31.6 ± 21.8 months (range, 12-136 months). Demographic variables (age, sex, arm dominance, body mass index, working status, bone mineral density [BMD]), clinical variables (preoperative diagnosis, previous operation, implant design, preoperative clinical scores, screw size in glenoid fixation, postoperative rehabilitation), and radiographic variables (acromial thickness, critical shoulder angle, deltoid length, humeral offset to lateral acromion) were investigated. To determine risk correlation, univariate analysis and multivariate logistic regression analysis with calculated odds ratios (ORs) were performed. Results Postoperative acromial fractures occurred in 29 of the 787 shoulders with RTSA (3.7%). Acromial fractures were detected at a mean of 10.0 months (range, 1-66 months) postoperatively. Univariate analysis revealed that the occurrence of an acromial fracture was significantly associated with a previous operation (38% [11 of 29] vs. 21% [156 of 758], P = .025) and BMD (–2.33 vs. –1.74, P = .013). Multivariate logistic regression analysis found that the occurrence of a postoperative acromial fracture was significantly associated with a previous operation (P = .034; OR, 2.91; 95% confidence interval, 1.08-7.84) and deltoid length (P = .004; OR, 1.04; 95% confidence interval, 1.01-1.07). Conclusion Acromial fracture following RTSA is not an uncommon complication, with an overall incidence of 3.7%. A previous operation, increased deltoid length, and low BMD were risk factors of acromial fracture following RTSA.

Background The purpose of this study was to compare clinical and radiologic results between treatment with locking plate fixation and fibular allograft augmentation (FA) and treatment with locking plate fixation and additional inferomedial screws (IMSs) in 3- or 4-part proximal humeral fractures with medial comminution in geriatric patients. Methods We enrolled 164 patients with 3- or 4-part proximal humeral fractures with medial comminution who were treated with locking plates. The patients were divided into 2 groups according to additional augmented fixation procedures. The IMS group was composed of patients treated with additional IMSs (80 patients), whereas the FA group was treated with an additional fibular allograft (84 patients). On the basis of fracture classification, the IMS group was subdivided into those with 3-part fractures (52 patients) and those with 4-part fractures (28 patients) and the FA group was subdivided into those with 3-part fractures (55 patients) and those with 4-part fractures (29 patients). Clinical and radiographic results were compared and analyzed. Results In patients with 3-part fractures, no differences in clinical outcomes were found regardless of additional procedures. However, the FA group showed superior clinical outcomes in patients with 4-part fractures (P = .038 for Constant score and P = .045 for visual analog scale score). The postoperative neck-shaft angle was maintained in the FA group compared with the IMS group with both fracture types at the last follow-up (P = .048 for IMS vs FA with 3-part fractures and P = .023 for IMS vs FA with 4-part fractures). The number of complications was significantly higher in the IMS group (5.5%) than in the FA group (1.2%) (P = .001). Conclusion An FA technique is considered a primary additional procedure for medial support in patients with 4-part proximal humeral fractures involving medial metaphyseal comminution when treated with locking plate fixation.

This study used in vivo three-dimensional to two-dimensional image registration techniques to compare the glenohumeral kinematics of shoulders with massive rotator cuff tears that were successfully treated conservatively and those of normal shoulders.Ten patients (age, 67.4 ± 3.63 years) with massive rotator cuff tears on one side and without contralateral tears were enrolled. We performed computed tomography and fluoroscopy on both shoulder joints and created three-dimensional bone models of the humerus and scapula using image registration techniques. We measured the humeral superoinferior translation, angle of humeral external rotation, scapular upward rotation, scapular anteroposterior tilt, and scapular external rotation of the torn shoulders with good range of motion after effective conservative treatment and compared these measurements to those of the contralateral normal shoulders.There was a significant difference in the initial position of the humeral head relative to the glenoid in the tear group; it was 2.0 mm higher than that in the normal group (p .05). This difference disappeared in the range from 40° to full elevation. The scapular motion of the tear group was significantly more upwardly rotated than that of the normal group: by 9.9° at rest (p .05) and by 11.6° at terminal elevation (p .05). No significant differences were detected for humeral head external rotation, scapular anteroposterior tilt, and scapular external rotation between the two groups.Kinematics of shoulders with massive cuff tears could not be recovered completely even though the patients had no significant symptoms after successful conservative treatment.

Acromioclavicular-coracoclavicular ligament injury occurs frequently, and the clavicle hook plate technique is an easy-to-use treatment method. However, complications such as subacromial impingement syndrome, synovitis, erosion, osteolysis, post-operative pain, and post-operative limitations in range of motion have been reported. We aimed to evaluate the use of the clavicle hook plate in the shoulder joints and to compare in vivo three-dimensional (3D) scapular kinematics and scapulohumeral rhythm between the shoulders with a clavicle hook plate and contralateral normal shoulder joints. Ten male patients (aged 40.5 ± 14.4 years) who underwent clavicle hook plate fixation for an acromioclavicular-coracoclavicular ligament injury were selected. Computed tomography and fluoroscopy were conducted on both the shoulder joints, and 3D models were created. Using a 3D-2D model-image registration technique, we determined the 3D coordinates of the scapula, and we measured the scapular kinematics and scapulohumeral rhythm. The values for upward rotation, posterior tilt, and external rotation in the two groups increased in proportion with humeral elevation, showing significant differences between the two groups (p

Background The purpose of this study was to evaluate the biomechanical properties of two different fixation constructs in varus collapse proximal humerus fracture, locking plate with medial support screw and locking plate with intramedullary fibular graft. Methods We used 8 pairs of undamaged fresh-frozen humen cadaveric humeri and fibula from patients ranging in age from 62 to 81 years. We simulated a proximal humerus fracture with medial comminution using wedge shaped osteotomy. One group was fixed with locking plate with medial support screws, the other group with locking plate with intramedullary fibular graft. Biomechanical test was carried out using servohydraulic material testing system. We measured displacement of specimens under cyclic load test, maximum failure load, initial stiffness, and mode of failure under increasing load test. Findings Under cyclic loading, the displacement of the specimen was significantly less in the locking plate with fibular strut graft group than in the locking plate with medial support screws group. (p = 0.012) Under increasing load test, the Locking plate with fibular strut graft group showed higher values in both maximum failure load and initial stiffness than the Locking plate with medial support screws group, and this was statistically significant. (p = 0.012, p = 0.001). Interpretation In biomechanical study, the locking plate with fibular strut graft showed significantly better results in all of the maximum failure load, initial stiffness, and gap depletion compared to the locking plate with medial support screws. Level of evidence Level IV.

ObjectiveTo describe the incidence of injuries and illnesses sustained during the XXIII Olympic Winter Games, hosted by PyeongChang on 9–25 February 2018.MethodsWe recorded the daily number of athlete injuries and illnesses (1) through the reporting of all National Olympic Committee (NOC) medical teams and (2) in the polyclinic and medical venues by the PyeongChang 2018 medical staff.ResultsIn total, 2914 athletes (1210 women, 42%; 1704 men, 58%) from 92 NOCs were observed for occurrence of injury and illness. NOC and PyeongChang 2018 medical staff reported 376 injuries and 279 illnesses, equalling 12.6 injuries and 9.4 illnesses per 100 athletes over the 17-day period. Altogether, 12% of the athletes incurred at least one injury and 9% at least one illness. The injury incidence was highest in ski halfpipe (28%), snowboard cross (26%), ski cross (25%), snowboard slopestyle (21%) and aerials (20%), and lowest in Nordic combined, biathlon, snowboard slalom, moguls and cross-country skiing (2%–6%). Of the 376 injuries recorded, 33% and 13% were estimated to lead to ≥1 day and >7 days of absence from sport, respectively. The highest incidences of illness were recorded in biathlon (15%), curling (14%), bobsleigh (14%) and snowboard slalom (13%). Thirty per cent of the illnesses were expected to result in time loss, and 70% affected the respiratory system. Women suffered 61% more illnesses than men.ConclusionOverall, 12% of the athletes incurred at least one injury during the Games and 9% an illness, incidences that are similar to the Olympic Winter Games of 2010 and 2014.

Numerous surgical options have been introduced for the treatment of chronic refractory lateral epicondylitis of the elbow, but it remains unclear which option is superior. The clinical outcomes of an open surgery group and an arthroscopic surgery group were evaluated, and the results of the 2 procedures were compared. From among patients with lateral epicondylitis refractory to 6 months of conservative treatment, 68 patients satisfying study criteria were recruited. Open surgery was performed in 34 cases (group 1), and arthroscopic surgery was performed in 34 cases (group 2). Compared with preoperatively, the 2 groups had significantly improved values for grip strength, range of motion, and Disabilities of the Arm, Shoulder and Hand score at 12 months postoperatively. Group 1 had significantly greater improvements in grip strength and visual analog scale pain score compared with group 2 ( P =.048 vs P =.006). Group 2 had significantly greater ( P =.045) improvement in pronation compared with group 1. Group 2 returned to work sooner than group 1. On the questionnaire regarding satisfaction with surgery 24 months postoperatively, 4 patients (12%) in group 2 reported dissatisfaction compared with no patients in group 1. Open surgery and arthroscopic surgery both yielded good clinical results. Nonetheless, for patients requiring muscle strength or having severe pain at work, open surgery would be more effective. [ Orthopedics . 2018; 41(4):237–247.]

Background The purpose of this study is to describe and analyze the shoulder injuries in elite athletes during the 2018 Winter Olympics in Pyeongchang. Methods To collect the data of all Olympic athletes who visited venue medical centers, polyclinics, and Olympic-designated hospitals for shoulder injuries during the Olympic Games (February 9 through 25, 2018), we reviewed Olympic electronic medical records and patient information obtained from Olympic medical service teams about athletes who complained of shoulder pain. Results During the Olympics, a total of 14 athletes visited clinics for shoulder-related symptoms. Five athletes were injured in games and nine were injured in training. The injury was due to overuse in four patients. Ten patients had trauma-related symptoms: one after being hit by an opponent and the other nine after a collision with the ground or an object. There were no patients who complained of symptoms related to pre-existing shoulder conditions. The most common cause of shoulder pain was snow-boarding (one big air and three slopestyle). The most common diagnosis was contusion (n = 6), followed by rotator cuff injuries (n = 3), superior labrum from anterior to posterior lesion (n = 1), sprain (n = 1), acromioclavicular-coracoclavicular injury (n = 1), dislocation (n = 1), and fracture (n = 1). Conclusions To the best of our knowledge, this study is the first epidemiologic study of shoulder injury conducted during a huge sports event involving a variety of competitions for elite athletes. If the risk factors of shoulder injury can be established by continuing research in the future, it will be helpful to prevent injury and to prepare safety measures for athletes.

Background We sought to estimate the ultimate tensile strength after metacarpal shaft fracture repair in adults using three operative fixation methods: plate fixation, Kirschner wire (K-wire) fixation, and intramedullary headless compression screw fixation. We also compared the advantages and disadvantages of each operative technique. Methods We acquired 30 metacarpal bones from four Korean adult cadavers without trauma, operative history, or deformities. The 30 metacarpal bones were divided into ten groups consisting of three metacarpal bones each with matching sizes and lengths. They were fractured, reduced, and fixed with plate and screws, K-wires, or headless compression screws. We performed force testing, collected ultimate tensile strength data, and created a stress-strain graph. Results The ultimate tensile strength of ten groups according to the fixation method was as follows: late and screw fixation, 246.1 N (range, 175.3 to 452.4 N); K-wire fixation, 134.6 N (62.7 to 175.0 N); and intramedullary headless compression screw fixation, 181.2 N (119.2 to 211.7 N). The median tensile strength of each fixation method was significantly different. In addition, the post-hoc test showed significant difference between the plate and screw fixation and K-wire fixation, between the headless compression screw fixation and K-wire fixation, and between the headless compression screw fixation and plate and screw fixation. Conclusions The tensile strength median values decreased in the following order showing significant differences among the fixation methods: plate and screw fixation, headless compression screw fixation, K-wire fixation. Significant differences were also observed between the plate and screw fixation and K-wire fixation, between the headless compression screw fixation and K-wire fixation, and between the headless compression screw fixation and plate and screw fixation.

The purpose of this study was to investigate whether healed tuberosities yield better rotational range of motion (ROM) and functional outcomes compared with unhealed tuberosities after reverse shoulder arthroplasty in elderly patients with comminuted proximal humerus fractures.This study included 38 patients who underwent reverse arthroplasty because of 4-part proximal humerus fractures; 14 patients had healed tuberosities (group A) and 24 patients had unhealed tuberosities (group B). Functional assessments included visual analog scale pain score, American Shoulder and Elbow Surgeons score, Constant score, and active ROM.There were no significant differences in the patients' demographics between the 2 groups. At final follow-up, no significant differences were found between groups in visual analog scale score (group A, 1.4; group B, 1.6; P = .647), American Shoulder and Elbow Surgeons score (74.3 and 70.7; P = .231), and Constant score (67.9 and 63.9; P = .228) and ROM with forward flexion and internal rotation. However, in external rotation, there was a significant difference between groups (29° and 10° in external rotation with the elbow at the side [P .001]; 25° and 7° in external rotation with shoulder abduction [P .001]).After reverse shoulder arthroplasty for 4-part proximal humerus fracture, tuberosities were healed in an anatomic position in 37% of patients. However, there were no significant differences in functional outcomes and ROM between the 2 groups, with the exception of external rotation, which was better in the healed tuberosity group. Therefore, tuberosity healing is not a prerequisite for satisfactory outcomes after reverse shoulder arthroplasty for 4-part proximal humerus fractures in elderly patients.

In spite of many excellent outcomes with arthroscopic anterior cruciate ligament (ACL) reconstruction, problems remain with this procedure; rotation instability and physical disabilities are not always completely resolved.1,2) Rotation stability has been achieved by tunneling the femur at the 10-o'clock position or by double bundle ACL reconstruction.3-8) However, there has been a great deal of debate as to the ability of the double bundle technique with respect to the selection of grafts, fixation methods, and techniques for tightening each bundle.4,5,8,9) Complications of this technique have included failure of graft fixation and excessive tunnel dilation due to an increase in tunnel numbers and adversity when an operation has required revision. Endobutton (Smith & Nephew, Andover, MA, USA) was introduced and commonly used as a femoral fixation method to overcome limitations in length and thickness of the autograft.5) However, Endobutton has had some problems in the graft healing in the bony tunnel due to shortening of grafted tendons, as well as excessive dilation of tunnels for the receipt of Endobuttons.10) For this reason, we minimized graft motion by fixating the graft with a bio-absorbable transfemoral pin, Rigidfix pin (Mitek, Johnson and Johnson, Raynham, MA, USA). In order to restore the native tibial insertion of ACL, the Retroscrew (Arthrex, Naples, FL, USA) was designed and introduced. It was proven to facilitate optimum joint line fixation at the level of the intercondylar floor for soft tissue autografts and allografts to maximize graft stiffness, fixation strength, abrasion resistance, and anatomical placement.11) To prove its advantages in the clinical setting and in clinical outcomes, we used the Retroscrew as a tibial fixation to the articular outlet of the tibial tunnel for anteromedial (AM) bundle. In addition, for further fixation to the distal portion, the gracillis and semi-tendinosus tendons, without detachment of the tibial insertion, were used for the posterolateral (PL) bundle, and a bio-absorbable interference screw, Intrafix (Mitek, Johnson and Johnson), was also applied to the articular outlet of the PL femoral tunnel in order to minimize graft motion. Thus, we designed a clinical study to investigate the clinical outcomes of this technique.

Scapular fractures account for approximately 1% of all fractures, and 8% to 10% are acromion fractures. We compared the results of early and delayed treatment for non-displaced and type III acromion fractures, respectively, to investigate an early treatment method for nondisplaced acromion fractures. Patients treated between March 1999 and March 2006 with 2-year follow-up were selected for the study. The early fixation group comprised 16 patients, and the delayed reconstruction group comprised 18 patients. Moreover, the delayed reconstruction group was further divided into 2 additional groups: delayed group B and delayed group N. Delayed group B comprised 7 cases receiving bone graft, and delayed group N comprised 11 cases not receiving bone graft. Mean Constant scores were significantly greater for the early fixation group (92±6.6; range, 64–98) than for both delayed groups N (86±7.8; range, 54–96) and B (81±9.4; range, 58–92) ( P =.042 and .024, respectively). Mean pain score was 14±4.8 (range, 5–15) in the early fixation group, 12±7.4 (range, 5–15) in delayed group N, and 9±8.8 (range, 5-15) in delayed group B ( P =.052 and .018, respectively). Mean daily activity score was also significantly greater in the early fixation group (19±6.4; range, 16–20) than in both delayed group N (14±6.2; range, 10–18) and delayed group B (10±4.4; range, 8–18) ( P =.048 and .021, respectively). The P values for Constant, pain, and daily activity scores between delayed groups N and B were .048, .038, and .052, respectively. In cases of young patients with type IC acromion fractures at the time of injury, a high activity level, and the early need for crutches or a walker, early surgical treatment should be considered.

Purpose The purpose of this study is to investigate and analyze accom-panying lesions including injury types of anteroinferior labrum lesion in young and active patients who suffered traumatic anterior shoulder dislocation for the first time. Meterials and Methods The study used magnetic resonance angiography (MRA) to 40 patients with acute anterior shoulder dislocation from April 2004 to April 2008, and of those, 36 with abnormal MRA finding were treated with arthroscopy. Results There was a total of 25 cases of anteroinferior glenoid labrum lesions. A superior labrum anterior-posterior lesion (SLAP) lesion was observed in 8 cases. For bony lesions, 22 cases of Hill-sachs lesions, 4 cases of lesions in greater tuberosity fracture of humerus, and 4 cases of loose body were found. For lesions involving rotator cuff, partial articular side rupture was found in 2 cases and 2 cases were found to have a complete rupture. Conclusion Under MRA and arthroscopy performed on patients with acute anterior shoulder dislocation, it was observed to have varying types of anteroinferior labrum lesions such as Perthes, Bankart, ALPSA, and bony Bankart lesion. that MRA is a remar-kably useful tool to classify various lesions in acute anterior dislocation of the shoulder and to make a diagnosis, making it a useful tool to decide a treatment method while consulting patients and their families.

A four-channel impedance measurement system, including a two-channel goniometer, to analyse human arm movement, was constructed. Impedances and joint angles were simultaneously measured for wrist and elbow movements. As the impedance changes resulting from wrist and elbow movements depended heavily on electrode placement, the optimum electrode configurations for those movements were determined by searching for high correlation coefficients, large impedance changes and minimum interferences in ten subjects (age: 29 +/- 6 years). The optimum electrode configurations showed very strong relationships between the wrist joint angle and forearm impedance (correlation coefficient= 0.95 +/- 0.04) and between the elbow joint angle and upper arm impedance (correlation coefficient= -0.97 +/- 0.03). Although the measured impedance changes of the wrist (1.1 +/-1.5 ohms) and elbow (-5.0 +/-2.9 ohms) varied between individuals, the reproducibilities of wrist and elbow impedance changes of five subjects were 5.8 +/- 1.8% and 4.6 +/- 1.4% for the optimum electrode pairs, respectively. It is proposed that this optimum electrode configuration would be useful for future studies involving the accurate measurement of arm movements by the impedance method.

Shoulder dislocation is frequently encountered by orthopedists, and closed manipulation is often sufficient to treat the injury in an acute setting. Although most dislocations are diagnosed and managed promptly, there are rare cases that are missed or neglected, leading to a chronically dislocated state of the joint. They are usually irreducible and cause considerable pain and functional disability in most affected patients, prompting the need to find a surgical method to reverse the worsening conditions caused by the dislocated joint. However, there are cases of even greater rarity in which chronic shoulder dislocations are asymptomatic with minimal functional or structural degeneration in the joint. These patients are usually left untreated, and most show good tolerance to their condition without developing disabling symptoms or significant functional loss over time. We report on one such patient who had a chronic shoulder dislocation for more than 2 years without receiving treatment.

Background Some authors have described the ganglion cyst of the spinoglenoidal notch as related to repetitive overhead activities and labral tear caused by trauma, while others have explained lesions of the capsulolabral complex and ganglion cysts to have separate pathologies. The purpose of this study is to compare clinical and radiological outcomes between 2 groups: 1 with superior labrum anterior and posterior (SLAP) repair only and the other with SLAP repair and cyst decompression prospectively. Materials and methods From August 2000 to March 2007, 28 patients matching the inclusion criteria were selected for the study. They were divided into 2 groups: 1 who received SLAP repair and the other with concomitant SLAP repair and cyst decompression. A visual analogue scale (VAS) and Rowe and Constant scores were used to make evaluation. Preoperative magnetic resonance images (MRIs) of 2 patient groups were compared with 2 follow-up MRIs taken 3 months after the operation and at final follow-up. Results Mean VAS and Constant and Rowe scores in groups I and II improved significantly from mean preoperative score compared to last follow-up score; however, there was no statistically significant difference between the 2 groups (P > .05). Preoperative MRI and arthroscopy revealed type II SLAP lesions and a type V lesion, respectively, as accompanying lesions in 24 cases. Conclusion The hypothesis stating 1-way valve mechanism of SLAP lesion as an initial cause of ganglion cysts has been proved indirectly in this study. Furthermore, direct decompression of the cyst does not lead to different results.

Background: Despite the attention that has been paid to restoration of the capsulolabral complex anatomic insertion onto the glenoid, studies comparing the pressurized contact area and mean interface pressure at the anatomic insertion site between a single-row repair and a double-row labral repair have been uncommon. Purpose: The purpose of our study was to compare the mean interface pressure and pressurized contact area at the anatomic insertion site of the capsulolabral complex between a single-row repair and a double-row repair technique. Study Design: Controlled laboratory study. Methods: Thirty fresh-frozen cadaveric shoulders (mean age, 61 ± 8 years; range, 48-71 years) were used for this study. Two types of repair were performed on each specimen: (1) a single-row repair and (2) a double-row repair. Using pressure-sensitive films, we examined the interface contact area and contact pressure. Results: The mean interface pressure was greater for the double-row repair technique (0.29 ± 0.04 MPa) when compared with the single-row repair technique (0.21 ± 0.03 MPa) ( P = .003). The mean pressurized contact area was also significantly greater for the double-row repair technique (211.8 ± 18.6 mm2, 78.4% footprint) compared with the single-row repair technique (106.4 ± 16.8 mm2, 39.4% footprint) ( P = .001). Conclusion: The double-row repair has significantly greater mean interface pressure and pressurized contact area at the insertion site of the capsulolabral complex than the single-row repair. Clinical Relevance: The double-row repair may be advantageous compared with the single-row repair in restoring the native footprint area of the capsulolabral complex.

The purpose of this study was to compare clinical outcomes between a primary dislocation group (group P) and a recurrent dislocation group (group R) with combined lesion of Bankart and type II SLAP lesions (type V SLAP lesion) and to evaluate incidence of type V SLAP lesion. In addition, the authors evaluated clinical outcomes of these patients by dividing two groups according to the sequence for Bankart and SLAP lesion suture. From May 2000 to May 2005, 310 patients who gave informed consent, underwent the diagnostic arthroscopy and magnetic resonance arthrography (MRA). One hundred and ten patients met the following criteria: (1) post-traumatic primary or recurrent anterior shoulder instability, (2) a normal contralateral shoulder, (3) a type V SLAP lesion, and (4) minimum follow-up of two years. Group P included 42 patients, and group R, 68 patients. Among all patients, 58 patients who had Bankart lesions sutured first were included in group B, and 52 who had their SLAP lesions sutured beforehand, group S. Visual analogue scale, range of motion, Rowe and Constant score were used to compare results between group P and group R, also group B and group S. The incidence rates of type V SLAP lesion were 42.8% in group P and 32.0% in group R. The overall treatment results in our study were good. Even if the difference between the two groups was statistically insignificant, group P showed greater recovery of range of motion than group R in external rotation. No significant difference was found between the two different operative methods according to suture sequence. The incidence rates of type V SLAP lesion were 42.8% in the primary dislocation group and 32.0% in the recurrent dislocation group. The overall treatment results in our study were good. Although there was no statistical significance in surgical time between the two groups, when both SLAP and Bankart lesions are present, the Bankart lesion must be sutured first to reduce surgical time.

BackgroundMany authors have reported the presence of intra-articular lesions after primary dislocation of the shoulder joint. However, few studies have focused on their prevalence or the differences in accompanying lesions between primary and recurrent dislocations of the shoulder joint.PurposeThis study was undertaken to investigate and analyze accompanying lesions, including types of anteroinferior labrum injuries, using diagnostic arthroscopy and magnetic resonance arthrography (MRA) in 144 patients with traumatic anterior dislocation of the shoulder joint.Study DesignCohort study; Level of evidence, 3.MethodsThere were 33 patients with 33 dislocations in the primary dislocation group and 111 patients with 111 dislocations in the recurrent dislocation group. Preoperative magnetic resonance arthrography and diagnostic arthroscopy were performed on all patients.ResultsIn the primary dislocation group, 8 Bankart lesions, 9 free anterior labrum periosteal sleeve avulsion (ALPSA) lesions, 4 bony Bankart lesions, and 1 adhesive ALPSA lesion were observed. In the recurrent dislocation group, 68 Bankart lesions, 11 free ALPSA lesions, 13 bony Bankart lesions, 16 adhesive ALPSA lesions, and 1 glenoid articular rim disruption lesion were found. There were 22 (66.6%) and 109 (98.1%) patients with lesions in the anteroinferior labrum in the primary and recurrent groups, respectively. There was a statistically significant difference between the 2 groups (P = .002). Also, there was a significant difference between the 2 groups in the prevalence of the Hill-Sachs lesion and inverted pear-shaped glenoid lesion (P = .008/P = .047). Inverted pear-shaped glenoids were observed in 15 patients in the recurrent group. In 139 of 144 patients, surgical findings of accompanying lesions coincided with magnetic resonance arthrography findings (96.5%).ConclusionVarious forms of anteroinferior labral lesions were seen in patients with traumatic anterior dislocation of shoulder. The recurrent dislocation group showed a significantly higher prevalence of anteroinferior labral lesions and bony lesions in comparison with the primary group. In our study, magnetic resonance arthrography was an accurate method to assess accompanying lesions in first-time and recurrent anterior dislocation of the shoulder, suggesting that this may be a useful tool for determining a treatment method.

The pulp test provides a means of examining the vitality of dental pulp using physical or chemical stimulation. During electrical pulp testing, an electrical current stimulates the intradental nerve, which may be painful and stressful to patients. The study involved measurement of the electromyogram (EMG) from the anterior belly of the digastric muscle, finger movement and voice response during electrical pulp testing. The excessive stimulus time from the onset time of response (EMG, voice and finger movement) to the end of the stimulation was obtained. The results indicated that the responses occurred in the order: EMG, finger and voice. Based on these results, an automatic stimulus shut-off circuit was developed using the above-mentioned responses to stimulus during electric pulp testing. Excessive stimulus time was reduced by prompt switching-off of the pulp tester output, 64 ms on average after the first detected response (EMG). Consequently, excessive stimulus times were reduced by 284 and 152 ms on average for the subject and examiner disconnection, respectively, using the developed automatic shut-off circuit. Therefore it was possible to minimise pain and stress by reducing excessive pulp stimulation.

Electronic root canal length measurement devices have made it easier and faster to measure the root canal length of a tooth compared with the conventional radiographic method. Of these electronic apex locators, the frequency-dependent type features greater accuracy and convenience in operation. However, its accuracy is still influenced by the presence of blood and/or the various electrolytes used in root canal therapy. This study describes the development of a new frequency-dependent electronic apex locator featuring electrolyte compensation, utilising an impedance ratio and voltage difference technique to minimise the influence of electrolytes on the accuracy of root canal length measurement. The errors for distances from file tips to apical constrictions were determined in vivo with the device operating with electrolyte compensation. The measured lengths were compared with the true lengths of the extracted teeth determined using a microscope. The mean error was +0.14+/-0.27mm, and 95.2% of the measurements were within the clinical tolerance of +/-0.5mm. It was also found that the degree of accuracy was not dependent on the size of the apical foramen (p = 0.74).