Abduction Angle Research Articles

Using mesh in capsule anatomical reconstruction to enhance the stability of high-dislocation-risk hip arthroplasty: a randomized controlled trial

BackgroundDislocation is a common complication after total hip arthroplasty (THA). This study aimed to compare the outcomes of mesh reconstruction versus conventional capsular repair in maintaining capsular integrity and preventing dislocation after THA.MethodsThis was a prospective, randomized controlled study of consecutive patients. A total of 124 high-dislocation-risk THAs were identified and randomized into two groups, one using mesh reconstruction and the other using the conventional capsular repair method. Perioperative data and radiological data were collected. Patients were followed up regularly. The main indices were the capsular integrity assessed by magnetic resonance imaging (MRI) and hip dislocation rate. The secondary indices included the Harris hip score (HHS), complications, and satisfaction.ResultsA total of 106 patients completed the follow-up and the average follow-up times were 19 ± 3.1 and 18 ± 3.3 months. The operation time of the mesh group was longer than that of the conventional group (P < 0.001). There were minor differences in acetabular anteversion and abduction angle, and the other data showed no differences. MRI results indicated that the success rate of capsular repair was higher in the mesh group (50 hips, 98%) than in the conventional group (37 hips, 67%) (P < 0.001), and the others failed the repair. Three dislocations occurred in the conventional group, while none occurred in the mesh group. The preoperative HHS (30 points) and postoperative HHS (82 points) of the mesh group were similar to those (35 points, 83 points) of the conventional group (P = 0.164, P = 0.328). Satisfaction had no difference (P = 0.532).ConclusionsCompared to conventional repair, mesh reconstruction can effectively maintain capsular integrity and decrease dislocation risk after THA without increasing complications.Level of evidence: Therapeutic study, Level IA.

Effect of intraarticular pressure on glenohumeral kinematics during a simulated abduction motion: a cadaveric study

BackgroundThe current understanding of glenohumeral joint stability is defined by active restrictions and passive stabilizers including naturally-occurring negative intraarticular pressure. Cadaveric specimens have been used to evaluate the role of intraarticular pressure on joint stability, although, while the shoulder’s negative intraarticular pressure is universally acknowledged, it has been inconsistently accounted for.HypothesisDuring continuous, passive humeral abduction, releasing the native intraarticular pressure increases joint translation, and restoring this pressure decreases joint translations.Study designDescriptive Laboratory Study.MethodsA validated shoulder testing system was used to passively abduct the humerus in the scapular plane and measure joint translations for seven (n = 7) cadaveric specimens. The pressure within the glenohumeral joint was measured via a 25-gauge needle during passive abduction of the arm, which was released and subsequently restored. During motion, the rotator cuff muscles were loaded using stepper motors in a force feedback loop and electromagnetic sensors were used to continuously measure the position of the humerus and scapula. Joint translation was defined according to the instant center of rotation of the glenohumeral head according to the recommendations by the International Society of Biomechanics.ResultsArea under the translation versus abduction angle curve suggests that releasing the pressure within the capsule results in significantly less posterior translation of the glenohumeral head as compared to intact (85–90˚, p < 0.05). Posterior and superior translations were reduced after 70˚ of abduction when the pressure within the joint was restored.ConclusionWith our testing system employing a smooth continuous passive motion, we were able to show that releasing intraarticular pressure does not have a major effect on the path of humeral head motion during glenohumeral abduction. However, both violating the capsule and restoring intraarticular pressure after releasing alter glenohumeral translations. Future studies should study the effect of simultaneous external rotation and abduction on the relationship between joint motion and IAP, especially in higher degrees of abduction.Clinical relevanceThoroughly simulating the glenohumeral joint environment in the cadaveric setting may strengthen the conclusions that can be translated from this setting to the clinic.

Ex vivo evaluation of arthroscopically assisted shoulder stabilization in dogs using an intra-articular aiming device.

To evaluate the use of an intra-articular aiming device (IAD) for medial shoulder stabilization with a suture-toggle repair or an interference screw repair using bone anchors in dogs. Ex-vivo Study METHODS: Specimens were randomly divided into 2 groups (anchor and suture-toggle) with 10 shoulders each. Abduction angles were measured by goniometry prior to and following medial glenerohumeral ligament transection and after receiving arthroscopically assisted stabilization with either bone anchors or suture-toggle constructs. Bone stock and insertion angles were measured with computed tomography scans. All specimens were inspected by dissection. Abduction angles increased post-transection in both groups, and were restored to normal in the anchor group, but 2° smaller than normal in the suture-toggle group following stabilization. Median magnitude of bone stock surrounding all tunnels ranged between 5.9 and 12.9 mm in the anchor group and 8.8 and 15.6 mm in the suture-toggle group (p=.002). Median insertion angles at the cranial glenoid, caudal glenoid, and humerus were 17.3°, 36.8 ° and 43.4° in the anchor group, respectively, and median insertion angles at the glenoid and humerus were 38.2° and 35.6° in the suture-toggle group, respectively (p=.91). Placement of anchors were not feasible in 3 specimens in the anchor group, and mild violations of the articular surfaces were detected in 3 specimens overall. Arthroscopically assisted shoulder stabilization with an IAD was feasible in canine cadavers. An IAD may facilitate arthroscopic shoulder stabilization in dogs. Further studies are warranted to evaluate safety and efficacy in a clinical setting.

Association of Proximal and Distal Factors With Lower Limb Kinematics During a Classical Ballet Jump

Excessive dynamic lower limb misalignment may predispose ballet dancers to jump-related injuries. However, it is unknown whether proximal and distal factors influence this movement pattern. The aim of this study was to investigate whether hip abduction strength, foot alignment, and ankle dorsiflexion range of motion (ROM) are associated with peak angles of hip adduction and internal rotation and knee abduction during the preparation and landing phases of a classical ballet jump. Cross-sectional study. Forty-one healthy amateur ballet dancers were included. Hip abduction strength was evaluated isometrically using a handheld dynamometer, foot alignment was determined by the shank-forefoot alignment, and weight-bearing ankle dorsiflexion ROM was measured by performing the lunge test. Peak hip and knee angles were analyzed 3-dimensionally during the preparation and landing phases of a single-leg jump. A Pearson correlation matrix was used to investigate the association of hip abduction strength, shank-forefoot alignment, and ankle dorsiflexion ROM with peak angles of hip adduction and internal rotation and knee abduction during the preparation and landing phases of the jump. Greater hip abduction strength was associated with greater peak hip internal rotation angle (r = .43, P < .05), but not with peak hip adduction and knee abduction angles during the preparation phase of the jump. There were no associations of shank-forefoot alignment and ankle dorsiflexion ROM with peak hip and knee angles during the preparation (r = -.23 to .36, P > .05) and landing (r = -.20 to .24, P > .05) phases of the jump. There was no association of hip abduction strength with peak hip and knee angles during the landing phase of the jump (r = -.28 to .16, P > .05). Hip abductors strengthening, correction of foot misalignments, and increasing ankle dorsiflexion ROM may not prevent excessive hip and knee movements during a classical ballet single-leg jump in amateur dancers.

Evaluation of Comparative Efficacy and Safety of Surgical Approaches for Total Hip Arthroplasty

Each approach for primary total hip arthroplasty (THA) has a long learning curve, so a surgeon's choice to change their preferred approach needs to be guided by clear justifications. However, current evidence does not suggest that any of the THA approaches are more beneficial than others, and the choice of approach is mainly based on the knowledge and experience of the surgeon and individual patient characteristics. To assess the efficacy and safety associated with different surgical approaches for THA. A comprehensive search of PubMed, EMBASE, and Cochrane databases from inception to March 26, 2022; reference lists of eligible trials; and related reviews. Randomized clinical trials (RCTs) comparing different surgical approaches, including the 2-incision approach, direct anterior approach (DAA), direct lateral approach (DLA), minimally invasive direct lateral approach (MIS-DLA), minimally invasive anterolateral approach (MIS-ALA), posterior approach (PA), minimally invasive posterior approach (MIS-PA), and supercapsular percutaneously assisted total hip arthroplasty (SuperPath), for primary THA. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, 2 reviewers independently extracted data on study participants, interventions, and outcomes as well as assessed the risk of bias using the Cochrane risk of bias tool and the certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation framework. A frequentist framework was used to inform a series of random-effects network meta-analyses. The outcomes were hip score (range, 0-100, with higher scores indicating better overall hip condition), pain score (range, 0-100, with higher scores indicating more pain), hospitalization time, operation time, quality of life score, blood loss, cup abduction angle, and cup anteversion angle. Of 2130 retrieved studies, 63 RCTs including 4859 participants (median [IQR] age, 64.0 [60.3-66.5] years; median [IQR] percentage male, 46.74% [38.64%-54.74%]) were eligible for analysis. Eight surgical approaches were evaluated. For hip score, DAA (mean difference [MD], 4.04; 95% CI, 1.92 to 6.16; moderate certainty), MIS-ALA (MD, 3.00; 95% CI, 0.43 to 5.59; moderate certainty), MIS-DLA (MD, 3.37; 95% CI, 1.05 to 5.68; moderate certainty), MIS-PA (MD, 4.46; 95% CI, 1.60 to 7.31; moderate certainty), PA (MD, 4.37; 95% CI, 1.87 to 6.88; high certainty), and SuperPath (MD, 5.00; 95% CI, 0.58 to 9.42; high certainty) were associated with greater improvement in hip score compared with DLA. DLA was associated with lower decrease in pain score than SuperPath (MD, 1.16; 95% CI, 0.13 to 2.20; high certainty) and MIS-DLA (MD, 0.90; 95% CI, 0.04 to 1.76; moderate certainty). PA was associated with shorter operation times compared with 2-incision (MD, -23.85 minutes; 95% CI, -36.60 to -11.10 minutes; high certainty), DAA (MD, -13.94 minutes; 95% CI, -18.79 to -9.08 minutes; moderate certainty), DLA (MD, -10.50 minutes; 95% CI, -16.07 to -4.94 minutes; high certainty), MIS-ALA (MD, -6.76 minutes; 95% CI, -12.86 to -0.65 minutes; moderate certainty), and SuperPath (MD, -13.91 minutes; 95% CI, -21.87 to -5.95 minutes; moderate certainty). The incidence of 6 types of complications did not differ significantly between the approaches. In this study, moderate to high certainty evidence indicated that compared with PA, all surgical approaches except DLA were associated with similar improvements of hip score but longer operation time. DLA was associated with smaller improvement of hip score. The safety of the different approaches did not show significant differences. These findings will help health professionals and patients with better clinical decision-making and also provide references for policy makers.

Cognitive Load Influences Drop Jump Landing Mechanics During Cognitive-Motor-Simulated Shooting.

Military duties require immense cognitive-motor multitasks that may predispose soldiers to musculoskeletal injury. Most cognitive challenges performed in the research laboratory are not tactical athlete specific, limiting generalizability and transferability to in-field scenarios. The purpose of this study was to determine the impact of a cognitive-motor multitask (forward drop jump landing while simultaneously performing simulated shooting) on knee kinetics and kinematics. Twenty-four healthy collegiate Reserve Officer's Training Corps members (18 males and 6 females, 20.42 ± 1.28 years, 174.54 ± 10.69 cm, 78.11 ± 14.96 kg) volunteered, and knee kinetics and kinematics were assessed between baseline and cognitive-loaded conditions. Repeated measures ANOVAs were conducted for each dependent variable with the within-subject factor of condition (baseline vs. cognitive load). Univariate ANOVAs indicated that knee flexion angle at initial contact (IC) (decreased 6.07°; d = 3.14), knee flexion displacement (increased 6.78°; d = 1.30), knee abduction angle at IC (increased 2.3°; d = 1.46), peak knee abduction angle (increased 3.04°; d = 0.77), and peak vertical ground reaction force (increased 0.81 N/kg; d = 2.13) were significant between conditions (P < .001). Therefore, cognitive load resulted in decreased knee flexion and increased knee abduction angle at IC and greater peak vertical ground reaction force, all factors commonly associated with knee injury risk. Peak knee flexion angle and knee abduction displacement were not significant between conditions (P > .05). Cognitive challenge induced knee landing biomechanics commonly associated with injury risk. Injury risk screening or return-to-training or duty assessments in military personnel might consider both baseline and cognitive conditions.

What exactly is "foot abduction" during management of idiopathic clubfoot in clinical practice?

There is however gross ambiguity regarding the use of term "foot abduction" in clubfoot treatment. We measured below defined angles at different stages of clubfoot treatment to decipher their precise interpretation. In a prospective evaluation of 25 unilateral clubfeet in infants' age less than sixmonths treated with Ponseti technique, clinical leg foot and thigh foot angle were measured at talar head reduction (LHT0), pre-tenotomy, and post-tenotomy stage. A "normal" reference was available in the form of measurements of contralateral limb. Talar head (LHT0) was reduced at mean leg foot angle of 26 degrees. The corresponding pre- and post-tenotomy angles were 42.6 and 50.0 degrees, respectively. The reference leg foot angles for contralateral limb were 49.8 degrees. The thigh foot angle for LHT0, pre-tenotomy, post-tenotomy, and contralateral side were, respectively, 39.2, 56, 68, and 65.6 degrees. There was an additional tibial external rotation component of mean 13.4 degrees (SD 4.5) in the thigh foot angle when compared to the leg foot angle at tenotomy. This increased to 18 degrees (SD 3.4) post-tenotomy. The study suggested that the foot abduction described in the "Ponseti Manual" probably intends thigh foot rather than leg foot angles. There was a significant difference in the angles when talar head reduced and tenotomy was decided. The foot abduction is an ambiguous term which should be replaced by the more specific leg or thigh foot abduction angle.

Application of artificial intelligence preoperative planning system in total hip arthroplasty for adult developmental dysplasia of the hip

By comparing with the traditional X-ray template measurement method, to explore the accuracy of artificial intelligence preoperative planning system (AI-HIP) to predict the type of prosthesis and guide the placement of prosthesis before total hip arthroplasty (THA) in adult patients with developmental dysplasia of the hip (DDH). Patients with DDH scheduled for initial THA between August 2020 and August 2022 were enrolled as study object, of which 28 cases (28 hips) met the selection criteria were enrolled in the study. Among them, there were 10 males and 18 females, aged from 34 to 77 years, with an average of 59.3 years. There were 12 cases of the left DDH and 16 cases of the right DDH. According to DDH classification, there were 10 cases of Crowe type Ⅰ, 8 cases of type Ⅱ, 5 cases of type Ⅲ, and 5 cases of type Ⅳ. According to Association Research Circulation Osseous (ARCO) staging of osteonecrosis of the femoral head, 13 cases were in stage Ⅲ and 15 cases in stage Ⅳ. The disease duration was 2.5-23.0 years (mean, 8.6 years). The limb length discrepancy (LLD) was 11.0 (8.0, 17.5) mm. Before operation, the prosthesis types of all patients were predicted by AI-HIP system and X-ray template measurement method, respectively. And the preoperative results were compared with the actual prosthesis type during operation in order to estimate the accuracy of the AI-HIP system. Then, the differences in the acetabular abduction angle, acetabular anteversion angle, femoral neck osteotomy position, tip-shoulder distance, and LLD were compared between preoperative planned measurements by AI-HIP system and actual measurement results after operation, in order to investigate the ability of AI-HIP system to evaluate the placement position of prosthesis. The types of acetabular and femoral prostheses predicted based on AI-HIP system before operation were consistent with the actual prostheses in 23 cases (82.1%) and 24 cases (85.7%), respectively. The types of acetabular and femoral prostheses predicted based on X-ray template measurement before operation were consistent with the actual prostheses in 16 cases (57.1%) and 17 cases (60.7%), respectively. There were significant differences between AI-HIP system and X-ray template measurement (P<0.05). There was no significant difference in acetabular abduction angle, acetabular anteversion angle, femoral neck osteotomy position, and tip-shoulder distance between AI-HIP system and actual measurement after operation (P>0.05). LLD after operation was significantly lower than that before operation (P<0.05). There was no significant difference between the LLD predicted based on AI-HIP system and the actual measurement after operation (P>0.05). Compared with the traditional X-ray template measurement method, the preoperative planning of AI-HIP system has better accuracy and repeatability in predicting the prosthesis type. It has a certain reference for the prosthesis placement of adult DDH.

Effects of different positions on rehabilitation after rotator cuff repair under shoulder arthroscopy

ObjectiveShoulder arthroscopic rotator cuff tear repair is currently the main treatment for full-thickness rotator cuff tears, and postoperative rehabilitation training is essential. However, pain and limitation of activity during the rehabilitation process will lead to poor results. Hence, identifying rehabilitation approaches is crucial. This study aimed to compare patient's rehabilitation outcomes and experience between rehabilitation in the supine position and in the standing position. MethodsThis prospective study included patients diagnosed with full-thickness rotator cuff tears who underwent shoulder arthroscopic double-row rivet repair at Sir Run Run Shaw Hospital, Zhejiang University School of Medicine from March 2019 to September 2021. The patients were randomly assigned to the standing rehabilitation exercise group (group A) and the supine rehabilitation exercise group (group B). All patients were followed up for 6 months to record and compare the visual analog scale (VAS) scores, shoulder range of motion, and rehabilitation compliance. ResultsAltogether, 86 patients participated in the study, of whom 79 patients completed the 6-month follow-up. Groups A and B had 39 and 40 patients, respectively. Before operation, the VAS score, forward flexion and extension angle, and abduction angle were comparable between groups A and B. After operation, the patients in groups A and B all experienced a significant improvement in the VAS score, forward flexion and extension angle, and abduction angle (p < 0.05). In addition, patients in group B had better VAS score (4.58 ± 0.87 vs. 5.21 ± 1.13, p = 0.0068; 2.15 ± 0.66 vs. 2.51 ± 0.51, p = 0.0078; 0.78 ± 0.86 vs. 1.33 ± 0.81, p = 0.0015), forward flexion and extension angle (109.30 ± 2.87 ° vs. 102.33 ± 3.74°, p = 0.0001; 109.53 ± 3.39° vs. 104.18 ± 2.76°, p = 0.0001; 125.22 ± 6.05° vs. 117.59 ± 2.27°, p = 0.0001), and abduction angle (91.78 ± 2.77° vs. 82.92 ± 2.12°, p = 0.0001; 91.62 ± 2.78° vs. 82.82 ± 1.45°, p = 0.0001; 109.48 ± 3.37° vs. 100.10 ± 2.94°, p = 0.0001) at 2 wk, 6 wk and 6 m postoperatively. ConclusionAfter 6 months of follow-up, the patients who performed rehabilitation exercises in the supine position achieved better rehabilitation outcomes than those who performed rehabilitation exercises while standing.

Robotic biomechanical evaluation of six different reverse shoulder implants

BackgroundThe reverse total shoulder arthroplasty is a popular surgical treatment for a degenerative shoulder with a nonfunctional rotator cuff. Currently, more than 36 different brands with small different features are available. This creates choice stress among many surgeons, who no longer know which parameters and surgical factors are important to optimize the placement of the implant. PurposeThe first purpose of this pilot study was to compare the passive range of motion (ROM) of 6 different implant designs implanted following the manufacturer’s guidelines. The second goal was to identify the impingements after implantation which determines the maximal ROM. The last goal of the study was to link the different parameters of an implant with the ROM. MethodsSix implant systems were implanted on identical sawbones. The procedure was repeated 3 times on a different sawbone to objectify the surgical repeatability of the procedures. A Stäubli TX-90 robot was used to perform and control the humerus' kinematic movement. An optical tracking system was used to perform the system's calibrations, track the humerus and scapula in space, and compute the center of rotation. ResultsThere was a wide ROM in the scapular plane (44.8°-105.5°) while the minimal elevation (adduction) varied between −4.8° and 35.6°. The rotational movements were limited by contact of the superior humeral polyethylene inlay and the inferior scapular neck. The adduction in the coronal and scapular plane was limited by inferior scapular impingement, whereas the maximal abduction was limited either by bony contact between the humerus and acromion or by contact between the humeral polyethylene inlay and the superior glenoid cavity. A bigger radius of the glenosphere resulted in a larger passive humeroscapular ROM (P < .001). A larger Neck-Shaft-Angle results in a better abduction (P < .001) but compromised adduction (P < .001). The localization of the center of rotation has a significant impact on the ROM. The medialized designs have larger abduction and rotational angles (P < .001). ConclusionThere is a wide variation in the measured glenohumeral ROM between the 6 frequently implanted prostheses. The most important factor to optimize the impingement-free ROM in all types of prostheses is the creation of the prosthetic overhang of the glenosphere to the bone. Too much lateralization of the center of the glenosphere with or without lateralization of the humeral stem can create a subacromial and/or subcoracoidal impingement.

The reliability of lower limb 3D gait analysis variables during a change of direction to 90- and 135-degree manoeuvres in recreational soccer players.

Several biomechanical outcomes are being used to monitor the risk of injuries; therefore, their reliability and measurement errors need to be known. To measure the reliability and measurement error in lower limb 3D gait analysis outcomes during a 90∘ and 135∘ change of direction (COD) manoeuvre. A test re-test reliability study for ten healthy recreational players was conducted at seven-day intervals. Kinematics (Hip flexion, adduction, internal rotation angles and knee flexion abduction angles) and kinetics (Knee abduction moment and vertical ground reaction force) data during cutting 90∘ and 135∘ were collected using 3D gait analysis and force platform. Five trials for each task and leg were collected. Standard error of measurement (SEM) and the intraclass correlation coefficient (ICC) were calculated from the randomised leg. The ICC values of the kinematics, kinetics, and vertical ground reaction force (VGRF) outcomes (90∘ and 135∘) ranged from 0.85 to 0.95, showing good to excellent reliability. The SEM for joint angles was less than 1.69∘. The VGRV showed a higher ICC value than the other outcomes. The current study results support the use of kinematics, kinetics, and VGRF outcomes for the assessment of knee ACL risk in clinic or research. However, the hip internal rotation angle should be treated with caution since the standard measurement error exceeded 10% compared to the mean value. The measurement errors provided in the current study are valuable for future studies.

Comparison Study of 5-Flap Z-Plasty and Double Z-Plasty for Interdigital Pocket Web Contractures

The aim of this study was to compare the improvement in abduction and change in web slope between 5-flap z-plasty and double z-plasty for post-burn or post-trauma interdigital pocket web contractures. We retrospectively reviewed 16 webs in 11 patients with post-burn or post-trauma interdigital pocket web contractures. Seven patients underwent 5-flap z-plasty and 4 double z-plasty. The abduction and slope angles of the affected fingers were measured before surgery and every 3 months after surgery. The follow-up time ranged from 12 to 36 months. The postoperative abduction angle improved in both groups. There was an increase of 19° ± 4° in the mean abduction angle after surgery in the 5-flap z-plasty group compared with a mean of 12° ± 2° in the double z-plasty group; the postoperative decrease in the web slope angle was 30° ± 5° and 22° ± 2°, respectively. All patients were able to actively move the affected webs and fingers with no pain or other discomfort. Five-flap z-plasty can be considered a better alternative to double z-plasty for interdigital pocket web contractures based on the improvement in abduction angle and changes in the slope angle. Therapeutic IV.

Effect of Pelvic Sagittal Tilt and Axial Rotation on Functional Acetabular Orientation.

Accurate and reproducible acetabular component positioning is among the most important technical factors affecting outcomes of total hip arthroplasty. Although several studies have investigated the influence of pelvic tilt and obliquity on functional acetabular anteversion, the effect of pelvic axial rotation has not yet been established. We analyzed a generic simulated pelvis created using preoperative full-body standing and sitting radiographs. A virtual acetabulum was placed in 144 different scenarios of acetabular anteversion and abduction angles. In each scenario, the effects of pelvic tilt and pelvic axial rotation on different combinations of acetabular orientations were assessed. The change in acetabular anteversion was 0.75° for each 1° of pelvic tilt and was most linear in abduction angles of 40°±45°. The change in acetabular anteversion was 0.8° for each 1° of pelvic axial rotation. Surgeons may consider adjusting acetabular anteversion in fixed axial pelvic deformities when the degree of deformity affects functional acetabular positioning, assessed from preoperative standing and sitting weight-bearing radiographs. [Orthopedics. 2023;46(1):e27-e30.].

Finite Element Analysis of Acetabulum Prosthesis' Lining Damage Zone with Different Implanting Angle.

Research the acetabular component's construction method of a three-dimensional finite element model in THA with different angles and study the influence of polyethylene liner wearing with finite element analysis. Build a model in the 3D modeling software system HyperMesh according to the artificial hip joint prosthesis' entities and data. Using a finite element analysis system, ABAQUS 6.11 reconstitute acetabular prosthesis after hip replacement joints under different implanting position angles. Simulation and load the joint load when sheet foot touchdown state. Calculate the plastic volume strain and fatigue fracture. The two groups of combinations of abduction angle 50° vs. anteversion angle 10° and abduction angle 55° vs. anteversion angle 15° have been found to have relatively smaller interface plastic strain and fatigue fracture volume value (2.241 × 10-7 m3, 2.443 × 10-7 m3), respectively. The groups of combinations of abduction angle 50° vs. anteversion angle 10° have been found to have relatively smallest interface plastic strain and fatigue fracture volume value in the total hip arthroplasty.

Biomechanical Characteristics of Scapular and Glenohumeral Movements during Pitching Motion in Injury-prone College Baseball Pitchers.

The coordination of glenohumeral (GH) and scapular movements is central to the injury prevention of baseball pitchers. However, there is no objective data establishing the direct relationship between pitching injuries and associated GH and scapular movements. Therefore, this study demonstrated the biomechanical differences in the scapular and GH movements during pitching between injury-prone pitchers and healthy college baseball pitchers. A total of 30 collegiate baseball pitchers were classified into two groups according to their injury status: injury-prone group (n = 15) and control group (n = 15). We obtained pitching motion data using three-dimensional motion analysis technique. The horizontal abduction angles of the GH joint during cocking and acceleration phases were considerably greater in the injury-prone pitchers (19.0° at stride foot contact [SFC], -4.0° at maximum external rotation [MER], and -0.3° at ball release) than those in healthy controls (11.7° at SFC, -10.0° at MER, and -6.9° at ball release). Additionally, in the cocking phase, the amount of angular change in the scapular external rotation (ER) was significantly smaller in the injury-prone group than that in the control group (mean difference, -13.0). These results suggest that the injury-prone pitchers have less internal rotation of the scapula and a more horizontal abduction of the GH joint during the cocking and acceleration phases. Therefore, sports medicine practitioners may need to pay considerable attention to the coordination of scapular and GH horizontal movements during pitching for prevention of shoulder injuries.

Evaluation of the abduction angles between hand fingers

Evaluation of the abduction angles between hand fingers

Partial persistent recovery of voluntary motility by auto-training in a clinical case of fingers paresis: A case report

In the paretic left hand of an eighty years old man only fingers flexion was voluntary possible and movement of extension, adduction or abduction needed mechanical help. After ten years, when fingers had progressively slightly more curled up, the subject discovered that voluntary movements of adduction and abduction became easily possible just by pressing the hand on a flat surface. Persistent voluntary hand motility was then partially obtained through specific self-trained exercise. The increase in the abduction angle was easily measured with a proctor and this is proposed as a simple clinical test to assess the improvement due to training. The case is analytically described.

Reliability of two devices for shoulder strength assessment: Wii Fit Balance Board and hand-held dynamometer.

The aim of this study was to compare the reliability and agreement between two devices - Wii Fit Balance Board (WBB) versus Hand-Held Dynamometer (HHD) to measure isometric strength during the athletic shoulder (ASH) test in healthy amateur rugby players. Fifteen males (23.73 ± 2.8 years) completed two testing sessions. Maximal isometric contractions using the dominant arm (D) and non-dominant arm (ND) against a WBB and HHD were assessed at three angles of abduction (180°, 'I'; 135°, 'Y' and 90°, 'T'), in a prone lying position. The results indicate a very large correlation between the HHD and the WBB. WBB provides acceptable reliability at I-Test D (CV = 9.97%, ICC = 0.88) and HHD in the I-Test D (CV = 8.90%, ICC = 0.94), I-Test ND (CV = 8.60%, ICC = 0.95) in peak strength values. The HHD is most reliable in D ASH I-Y-T (CV = 10.94%) and WBB (CV = 11.05%). In the ND ASH I-Y-T test, the HHD is the most reliable (CV = 12.5%) compared to the WBB (CV = 14.43%). These results suggest that WBB is a reliable device to assess strength in the ASH test with a very large correlation with the HHD. WBB and HHD are two affordable devices to assess isometric shoulder strength.

Indirect contact matters: Mid-flight external trunk perturbation increased unilateral anterior cruciate ligament loading variables during jump-landings

PurposeTo determine the effect of unanticipated mid-flight medial-lateral external perturbation of the upper or lower trunk on anterior cruciate ligament (ACL) loading variables during jump-landings. MethodsThirty-two participants performed double-leg vertical jump-landings while bilateral kinematics and kinetics were collected under 6 conditions (upper or lower trunk perturbation locations; no, left, or right perturbation directions). Two customized catapult apparatuses were created to apply pushing perturbation to participants near the maximal jump height. ResultsThe ball contacted participants near the center of mass for the lower-trunk conditions and approximately 23 cm above the center of mass for the upper-trunk conditions. Under upper-trunk perturbation, the contralateral leg demonstrated significantly smaller knee flexion angles at initial contact and greater peak knee abduction angles, peak vertical ground reaction forces, peak knee extension moments, and peak knee adduction moments compared to other legs among all conditions. Under lower-trunk perturbation, the contralateral leg showed significantly smaller knee flexion angles at initial contact and increased peak vertical ground reaction forces and peak knee extension moments compared to legs in the no-perturbation conditions. ConclusionMid-flight external trunk pushing perturbation increased ACL loading variables for the leg contralateral to the perturbation. The upper-trunk perturbation resulted in greater changes in ACL loading variables compared to the lower-trunk perturbation, likely due to trunk and ipsilateral leg rotation and more laterally located center of mass relative to the contralateral leg. These findings may help us understand the mechanisms of indirect-contact ACL injuries and develop jump-landing training strategies under mid-flight trunk perturbation to better prevent ACL injury.

Does the Dual Mobility Cup Reduce Dislocation After Primary Total Hip Arthroplasty in Elderly Patients at High Risk of Dislocation?

The dual mobility cup (DMC) is designed to extend the longevity of the prosthesis by improving stability, enhancing the range of motion, and decreasing impingement without increasing wear. We hypothesized that DMC would reduce the risk of dislocation in elderly patients. This study aimed to investigate the clinical and radiographic outcomes of DMC-total hip arthroplasty (THA) in elderly patients at high risk of dislocation. From June 2016 to March 2020, 94 patients with a mean age of 77.7 years (97 hips) who underwent a posterolateral approach for DMC-THA in our department were followed up for at least one year. Preoperative and postoperative pelvic tilt angles (PTA) and DMC orientation were prospectively collected for all patients. Intraoperative and postoperative complications were recorded. A parametric test was used for normal distribution, and a non-parametric test was used for non-normal distribution. Abduction and anteversion angles of the cup were 42.4 and 18.0° in the supine position immediately postoperative. The average PTA for patients in the supine and standing positions were 26.5 and 34.5°, respectively. When moving from the supine to the standing position, patients experienced a mean posterior pelvic tilt of 9°. No intraoperative acetabular-related complications were recorded. Postoperative complications included early infection in one patient (1.0%) and dislocation in one patient (1.0%). Our study demonstrates that DMC-THA provides satisfactory short-term outcomes in elderly patients at a high risk of dislocation, regardless of the change in PTA resulting from postural transition.