The possible relationship between the palmaris longus and joint hypermobility.

OBJECTIVE: The palmaris longus (PL) contributes to the palmar fascia, wrist flexion, hand muscle balance, and pinch strength. Also, PL is used as a graft source. So, PL's presence is helpful for joint stability and grafting. On the other hand, joint hypermobility (JH) is associated with many complaints and disorders. Considering the adverse effects of JH and benefit-based evolution, the genesis rather than agenesis of PL can be expected in JH. Herein, it was hypothesized that PL might be together with JH, and individuals with PL may have higher scores of JH than those without. PATIENTS AND METHODS: Between June 2023 and October 2023, 200 participants (F/M: 1/1) were included in the study. The Schaeffer's test and the Beighton scores were used to assess PL and JH, respectively. The participants were divided into two bilateral groups according to the presence or absence of PL. Then, the groups were compared for demographics and Beighton scores. Subgroup analyses were also done by considering gender. RESULTS: No significant differences were found between PL (+) and PL (-) groups considering females+males in age (p=0.559), gender (p=0.517), weight (p=0.375), height (p=0.061), work status (p=0.229), Beighton score (p=0.893), and JH (p=1.0). No significant differences were found between PL (+) and PL (-) groups considering females only in age (p=0.871), weight (p=0.189), height (p=0.127), work status (p=0.200), Beighton score (p=0.727), and JH (p=1.0). No significant differences were found between PL (+) and PL (-) groups considering males only in age (p=0.370), weight (p=0.981), height (p=0.400), BMI (p=0.601), work status (p=0.145), Beighton score (p=0.757), and JH (p=1.0). CONCLUSIONS: According to the results of this study, no relationship was found between PL and JH. However, this is the first study on the topic and has some limitations.

An investigation of sensory processing skills in toddlers with joint hypermobility.

BACKGROUND: Children with Generalized Joint Hypermobility (GJH) may have a motor developmental delay in the early period and subluxation, fatigue, autonomic dysfunction, and pain arising from ligaments and other soft tissues in advanced ages. Additionally, there is a loss of proprioceptive sensation in children and adults with GJH. AIMS: This study aimed to evaluate sensory processing skills in toddlers with GJH. STUDY DESIGN: A cross-sectional study. SUBJECTS: Fifty-eight children aged between 12 and 14 months were included in the study. These children were divided into two groups: with and without GJH (31 with GJH and 27 without GJH). OUTCOME MEASURES: The sensory processing skills of the children in the study were evaluated with the Test of Sensory Functions in Infants (TSFI). RESULTS: The scores in the subtests of TSFI in response to tactile deep pressure, adaptive motor functions, visual-tactile integration, and response to vestibular stimuli were higher in favor of children without GJH (p < 0.05). The total TSFI score was higher in the group without GJH (p < 0.05). CONCLUSIONS: Sensory processing problems were found in toddlers with GJH. Sensory motor development should be evaluated in children with GJH, and an appropriate early intervention program should be planned.

Effect of sensor location for modifying center of pressure during gait using haptic feedback in people with chronic ankle instability.

BACKGROUND: Gait retraining using haptic biofeedback medially shifts the center of pressure (COP) while walking in orthopedic populations. However, the ideal sensor location needed to effectively shift COP medially has not been identified in people with chronic ankle instability (CAI). RESEARCH QUESTIONS: Can a heel sensor location feasibly be employed in people with CAI without negatively altering kinematics? Does a heel sensor placement relative to the 5th metatarsal head (5MH) impact COP location while walking in people with CAI? METHODS: In this exploratory crossover study, 10 participants with CAI walked on a treadmill with vibration feedback for 10 minutes with a plantar pressure sensor under the heel and 5MH. Separate 2×2 repeated measures analyses of covariances (rmANCOVAs) were used to compare the averaged COP location and 3-D lower extremity kinematics from the first 10% of stance before and after training and between sensor locations. Baseline measures served as covariates to adjust for baseline differences. RESULTS: Feedback triggered by a heel sensor resulted in 40% of participants avoiding a heel strike. There were no significant main effects or interactions between time and sensor location on COP location when controlling for baseline COP (p>0.05). However, with the 5MH placement, participants displayed less ankle internal rotation(IR) (5MH/Heel: -4.12±0.00º/ -6.43±0.62º), less forefoot abduction (-4.29±0.00º/ -5.14±1.01º), more knee flexion (3.40±0.32º/ 0.14±0.57º), less knee external rotation (-10.95±0.00º/-11.24±1.48º), less hip extension (-0.20±0.00º/-1.42±1.05º), and less hip external rotation (3.12±0.00º/3.75±1.98º). SIGNIFICANCE: A 5MH location may be more feasible based on difficulties maintaining heel strike when the sensor was under the heel. While no sensor location was statistically better at changing the COP, the 5MH location decreased proximal transverse plane motions making participants' gait more like controls. Individual response variations support comprehensive lower extremity assessments and the need to identify responder profiles using sensory feedback in people with CAI.

The New Double-row Bankart Repair Recovered Shoulder Stability without Excessive Motion Limitation: A Case-Control Study with Single-row Bankart Repair.

OBJECTIVES: Bankart lesion is one of the most common lesions of the glenohumeral joint. Several double-row suture methods were reported for Bankart repair, which could provide more stability, yet more motion limitation and complications. Therefore, we introduced a new double-row Bankart repair technique, key point double-row suture which used one anchor in the medial line. The purpose of this article is to investigate the clinical outcomes of this new method and to compare it with single-row suture. METHODS: Seventy-eight patients receiving key point double-row suture or single-row suture from October 2010 to June 2014 were collected retrospectively. The basic information including gender, age, dominant arm, and number of episodes of instability was collected. Before surgery, the glenoid bone loss was measured from the CT scan. The visual analogue scale, American shoulder and elbow surgeons, the University of California at Los Angeles shoulder scale, and subjective shoulder value were valued before surgery and at the last follow-up. RESULTS: Forty-four patients (24 patients receiving single-row suture and 20 patients receiving key point double-row suture) were followed up successfully. The follow-up period was 9.2 ± 1.1 years (range, 7.8-11.4 years). At the last follow-up, no significant differences were detected for any of the clinical scores. The recurrence rate was 12.5% for the single-row group and 10% for the double-row group, respectively (p = 0.795) 14 patients (31.8%) in the single-row group and nine patients (26.5%) in the double-row group were tested for active range of motion. A statistically significant difference was found only for the internal rotation at 90° abduction (48.9° for single-row and 76.7° for key point double-row, p = 0.033). CONCLUSION: The key point double-row sutures for Bankart lesions could achieve similar long-term outcomes compared with single-row suture, and one medial anchor did not result in a limited range of motion. The low recurrence rate and previous biomechanical results also indicate the key point double-row suture is a reliable method.

A New Computed Tomography-Based Measure that Provides Insight Into Hip Stability in Patients With Posterior Wall Acetabular Fractures.

OBJECTIVES: To describe the technique and results of a new sagittal plane computed tomography (CT)-based angular measure for predicting stability after posterior wall acetabular fractures (PWF). DESIGN: Retrospective review. SETTING: Academic Level II trauma center. PATIENT SELECTION CRITERIA: Fifty-eight consecutive patients with PWF (AO/OTA class 62A.1), 98% were high-energy injuries. INTERVENTION: A new sagittal CT measure of PWF based on the angle subtending the joint center, cranial and caudal fracture exits. OUTCOME MEASURES AND COMPARISONS: Hip incongruity or dislocation demonstrated using gold standard test, examination under anesthesia (EUA), or instability on static images. Prediction of hip instability using a sagittal CT angular measure based on cranial and caudal fracture exits was compared with previous axial CT measures suggestive of increased risk for instability including posterior wall size >50%, and those with cranial exit within 5.0 mm of the acetabular dome. RESULTS: There were 32 operative and 26 nonoperatively treated fractures. Thirty fractures were determined to be unstable, and 28 were stable after EUA. Measurements of >70 degrees using the sagittal CT angular measure predicted instability in 28 of 28 patients, and ≤70 degrees predicted stability in 30 of 30 patients (sensitivity 100% and specificity 100%). Prevalence of EUA confirmed instability for subgroups with PWF based on prior axial CT measures were as follows: ≥50% wall involvement (11/16; sensitivity 67% and specificity 60%; 95% CI, 45%-89%/45%-75%), fracture within 5.0 mm of dome (5/18; sensitivity 86% and specificity 73%; 95% CI, 71%-100%/59%-87%), fracture within 5.0 mm of dome and ≥50% involvement (1/9; sensitivity 89% and specificity 56%; 95% CI, 69%-100%/24%-88%). CONCLUSIONS: In a sample of 58 mostly high energy posterior wall fractures all having had an EUA, a new sagittal angular CT measurement of ≤70 degrees predicted hip stability and >70 degrees predicted instability with 100% sensitivity and specificity. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

A Comparative Biomechanical Study of Alternative Medial Collateral Ligament Reconstruction Techniques.

BACKGROUND: There is little evidence of the biomechanical performance of medial collateral ligament (MCL) reconstructions for restoring stability to the MCL-deficient knee regarding valgus, external rotation (ER), and anteromedial rotatory instability (AMRI). HYPOTHESIS: A short isometric reconstruction will better restore stability than a longer superficial MCL (sMCL) reconstruction, and an additional deep MCL (dMCL) graft will better control ER and AMRI than single-strand reconstructions. STUDY DESIGN: Controlled laboratory study. METHODS: Nine cadaveric human knees were tested in a kinematics rig that allowed tibial loading while the knee was flexed-extended 0° to 100°. Optical markers were placed on the femur and tibia and displacements were measured using a stereo camera system. The knee was tested intact, and then after MCL (sMCL + dMCL) transection, and loaded in anterior tibial translation (ATT), ER, varus-valgus, and combined ATT + ER (AMRI loading). Five different isometric MCL reconstructions were tested: isolated long sMCL, a short construct, each with and without dMCL addition, and isolated dMCL reconstruction, using an 8 mm-wide synthetic graft. RESULTS: MCL deficiency caused an increase in ER of 4° at 0° of flexion (P = .271) up to 14° at 100° of flexion (P = .002), and valgus laxity increased by 5° to 8° between 0° and 100° of flexion (P < .024 at 0°-90°). ATT did not increase significantly in isolated MCL deficiency (P > .999). All 5 reconstructions restored native stability across the arc of flexion apart from the isolated long sMCL, which demonstrated residual ER instability (P≤ .047 vs other reconstructions). CONCLUSION: All tested techniques apart from the isolated long sMCL graft are satisfactory in the context of restoring the valgus, ER, and AMRI stability to the MCL-deficient knee in a cadaveric model. CLINICAL RELEVANCE: Contemporary MCL reconstruction techniques fail to control ER and therefore AMRI as they use a long sMCL graft and do not address the dMCL. This study compares 5 MCL reconstruction techniques. Both long and short isometric constructs other than the long sMCL achieved native stability in valgus and ER/AMRI. Double-strand reconstructions (sMCL + dMCL) tended to provide more stability. This study shows which reconstructions demonstrate the best biomechanical performance, informs surgical reconstruction techniques for AMRI, and questions the efficacy of current popular techniques.

Impact of Sacroiliac Interosseous Ligament Tension and Laxity on the Biomechanics of the Lumbar Spine: A Finite Element Study.

OBJECTIVE: To investigate the influence of sacroiliac interosseous ligament tension and laxity on the biomechanics of the lumbar spine. METHODS: A static analysis of a three-dimensional finite element model of the Lumbar-Pelvic is conducted to verify the model's effectiveness. Adjusting the sacroiliac ligament's elasticity modulus under a 10Nm lumbar flexion/extension moment, it simulates ligament tension/laxity to calculate vertebrae displacements, intervertebral disc stress and deformation, nucleus pulposus pressure, facet joint force, and ligament stress. RESULTS: With the elastic modulus of the sacroiliac ligament changing by +50%, -50%, and -90%, the angular displacement of vertebra 3 in forward flexion changes by +1.64%, -4.84%, and -42.3%, and the line displacements change by +5.7%, -16.4%, and -144.9%, respectively; and the angular displacements in backward extension change by +0.2%, -0.6%, -5.9% and the line displacements change by +5.5%, -14.3%, and -125.8%. However, the angular displacement and center distance between adjacent vertebrae do not change, leading to no change in the maximum stress of the intervertebral disc and the maximum pressure in the nucleus pulposus. Flexion and extension directly affect the deformation and stress magnitude and distribution in the lumbar spine. CONCLUSIONS: While sacroiliac interosseous ligament laxity and tension have little effect on disc deformation and stress, and nucleus pulposus pressure, they reduce the stability of the lumbar-sacral vertebrae. In a forward flexion state, the lumbar ligaments bear a large load and are prone to laxity, thereby increasing the risk of lumbar injury.

Difference of Knee Strength Recovery Between Revision and Primary ACL Reconstruction.

Different grafting procedures are available to restore knee stability after revision anterior cruciate ligament (ACL) reconstruction. We compared knee strength recovery between ACL revision surgery and primary reconstruction. One hundred and ten patients with ACL revision surgery were matched with 110 patients with primary reconstruction based on the graft procedure. The isokinetic knee strength had been assessed for the first 9 months post-surgery. Knee laxity, function, and activity score were also evaluated. Limb symmetry index for knee extensor and flexor strength was not different at 4-, 6- and 9-months post-surgery between revision surgery and primary reconstruction. These results depended on ipsilateral or contralateral graft choice. Ipsilateral hamstring tendon (HT) and contralateral bone-patellar-tendon-bone (BPTB) graft procedures were similar for a revision of a BPTB graft failure. Contralateral HT procedure was better than ipsilateral BPTB procedure for a revision of a HT graft failure. The early recovery of isokinetic knee strength after ACL revision surgery regardless of the HT or BPTB procedures, was similar to the recovery after primary ACL reconstruction with the same graft technique. These results apparently depended on a temporary quadriceps arthrogenic muscle inhibition and on a persistent donor site morbidity, concerning the new and the previous grafts, respectively.

Infraspinatus function impairment after arthroscopic Bankart repair with Hill Sachs remplissage. Isokinetic, functional, and radiographic analysis.

PURPOSE: Arthroscopic Bankart repair with Hill Sachs remplissage (BHSR) is an option for anterior shoulder instability with humeral defect. Our hypothesis was that infraspinatus capsulo-tenodesis is an effective solution, with good clinical results and no consequences on shoulder strength and ranges of motion. METHODS: We performed a retrospective case-control study involving 22 patients operated with arthroscopic BHSR. We compared isokinetic evaluation of both shoulders using a dynanometer in concentric, eccentric force and endurance. Ranges of motion were measured using a goniometer and compared to the contralateral unaffected side. Functional assessment included Constant, Rowe, Walch and Duplay and WOSI scores. Healing and fatty degeneration were analyzed with magnetic resonance imaging. RESULTS: At mean 37.2 months follow-up, 21 patients (95.4%) were satisfied or very satisfied with the intervention. Range of motion in external rotation of the affected side decreased by 10.8° in adduction and 6° at 90° of abduction (p<0.05). Deficit in external rotation strength of the affected side greater than 15% was found in all isokinetic tests (p<0.05). Walch and Duplay, Rowe, WOSI and adjusted Constant average scores were respectively 71.05±14.1 (40-90), 67.63±19.7 (15-100), 34.6%±19.9 (8.43-76.23) and 69.8±13.57 (36.7-101). Postoperative MRI showed good capsulo-tenodesis healing without infraspinatus muscle fatty degeneration. CONCLUSION: Arthroscopic BHSR provides satisfactory functional outcomes but significant infraspinatus functional impairments in both strength and ranges of motion in external rotation. LEVEL OF EVIDENCE: III; case-control study.

The moment arms and lines of action of subscapularis after the Latarjet procedure.

The Latarjet procedure is an established surgical treatment for recurrent glenohumeral joint instability with glenoid bone loss. Intraoperatively, the conjoint tendon and its attachement on the coracoid bone graft is routed through a split in subscapularis where the graft is fixed to and augments the anteroinferior glenoid. The objective of this in vitro study was to quantify the influence of glenohumeral joint position and conjoint tendon force on the lines of action and moment arms of subscapularis muscle sub-regions after Latarjet surgery. Eight fresh-frozen, entire upper extremities were mounted onto a testing apparatus, and a cable-pulley system was used to apply physiological muscle loading to the major shoulder muscles. The lines of action and moment arms of four subregions of subscapularis (superior, mid-superior, mid-inferior, and inferior) were quantified radiographically with the conjoint tendon unloaded and loaded while the shoulder was in (i) 0° abduction (ii) 90° abduction (iii) 90° abduction and full external rotation (ABER), and (iv) the apprehension position, defined as ABER with 30° horizontal extension. Conjoint tendon loading after Latarjet surgery significantly increased the inferior inclination of the lines of action of the mid-inferior and inferior subregions of subscapularis in the scapular plane in ABER and apprehension positions (p < 0.001), as well as decreased the horizontal flexion moment arm of the inferior subscapularis (p = 0.040). Increased subscapularis inferior inclination may ultimately increase inferior joint shear potential, while smaller horizontal flexion leverage may reduce joint flexion capacity. The findings have implications for Latarjet surgical planning and postoperative rehabilitation prescription.

Different gait pattern in adolescence with patellofemoral instability.

BACKGROUND: Patellofemoral instability influences the gait pattern and activity level in adolescents. However, gait biomechanics to cope with recurrent patella instability and its relation to radiological findings has hardly been studied. METHODS: We retrospectively analyzed kinematic and kinetic gait analysis data, magnetic resonance images and X-ray of 32 adolescents with unilateral recurrent patellofemoral instability aged 12 to 18 years. Subjects were assigned to 3 groups based on their sagittal knee moment in the loading response and mid stance phase. Kinematic and kinetic differences among the groups were analyzed using a one-way ANOVA. A multinomial logistic regression model provided a further analysis of the relationship between gait biomechanics and MRI as well as X-ray parameters. FINDINGS: All three groups showed different characteristics of the knee kinematics during loading response and single stance: while the patella-norm-loading group showed a slightly reduced knee flexion (p ã€ˆ0,01), the patella-unloading group kept the knee nearly extended (p < 0,01) and patella-overloading group showed an increased knee flexion (p = 0,01) compared to the other groups. In single stance the patella-overloading group maintained increased knee flexion (p < 0,01) compared to patella-unloading group and patella-norm-loading group. None of the radiological parameters proved to be related to gait patterns. INTERPRETATION: The paper describes different gait coping strategies and their clinical relevance in subjects with patellofemoral instability. However, we did not find any relation of gait biomechanics to skeletal morphology.

Inertial Sensor-Based Assessment of Static Balance in Athletes with Chronic Ankle Instability.

The Balance Error Scoring System (BESS), a subjective examiner-based assessment, is often employed to assess postural balance in individuals with chronic ankle instability (CAI); however, inertial sensors may enhance the detection of balance deficits. This study aimed to compare the BESS results between the CAI and healthy groups using conventional BESS scores and inertial sensor data. The BESS test (six conditions: double-leg, single-leg, and tandem stances on firm and foam surfaces, respectively) was performed for the CAI (n = 16) and healthy control (n = 16) groups with inertial sensors mounted on the sacrum and anterior shank. The BESS score was calculated visually by the examiner by counting postural sway as an error based on the recorded video. The root mean square for resultant acceleration (RMSacc) in the anteroposterior, mediolateral, and vertical directions was calculated from each inertial sensor affixed to the sacral and shank surfaces during the BESS test. The mixed-effects analysis of variance and unpaired t-test were used to assess the effects of group and condition on the BESS scores and RMSacc. No significant between-group differences were found in the RMSacc of the sacral and shank surfaces, and the BESS scores (P > 0.05), except for the total BESS score in the foam condition (CAI: 14.4 ± 3.7, control: 11.7 ± 3.4; P = 0.039). Significant main effects of the conditions were found with respect to the BESS scores and RMSacc for the sacral and anterior shank (P < 0.05). The BESS test with inertial sensors can detect differences in the BESS conditions for athletes with CAI. However, our method could not detect any differences between the CAI and healthy groups.

Sex differences in the relationship of hip strength and functional performance to chronic ankle instability scores.

BACKGROUND: While decreased hip abductor strength, functional performance, and self-reported instability scores have all been shown in association with CAI, any sex difference in the relationship between these indicators is unclear. This study was to determine whether sex differences are present in the relationship between these indicators in individuals with CAI. METHODS: Thirty-two women and twenty-nine men with unilateral CAI took part. Hip abductor strength and functional performance were respectively assessed using a hand-held dynamometer and the figure-8-hop test. All 61 participants scored the Cumberland Ankle Instability Tool (CAIT) for self-reported ankle instability. Independent sample t-tests and correlation analysis were conducted. RESULTS: Normalized hip abductor strength and functional performance measures for females were lower than for males. The self-reported ankle instability CAIT score, where higher values represent less instability, was significantly and positively correlated with both normalized hip abductor strength (p = 0.003) and functional performance (p = 0.001) on the affected side in females, but not in males (p = 0.361 and p = 0.192 respectively). CONCLUSIONS: Sex differences were observed in that there were significant relationships between normalized hip abductor strength, functional performance, and CAIT scores in female CAI participants, but not males, suggesting that CAI evaluation and rehabilitation strategies should be sex-specific. HIGHLIGHTS: In females with CAI, hip abductor strength and functional performance showed significant relationships with self-reported instability scores. Correspondingly, in clinical practice with individuals with CAI, evaluation criteria may be formulated according to these observed sex differences. Sex differences should be factored into the evaluation and treatment of CAI individuals. Hip strength assessment should be employed with CAI individuals. Hip strengthening and functional hopping may be recommended for the rehabilitation of CAI, especially in female patients.

Editorial Commentary: Double-Pulley Remplissage Using Transtendon Anchors: Keep It Simple.

A large Hill-Sachs lesion that engages the glenoid rim and predisposes to recurrent anterior instability confers a substantial management challenge. Arthroscopic remplissage, either in isolation or combined with anterior labral repair, gives the arthroscopic surgeon a tool to stabilize the shoulder without reverting to more extensive open procedures or bone block reconstructions. In arthroscopic remplissage, the posterior capsule and infraspinatus are sutured into the humeral defect to limit such engagement between the HilleSachs lesion and the glenoid rim. The double-pulley technique using 2 transtendon anchors makes arthroscopic remplissage technically simpler, and potentially more reproducible, than earlier techniques. As we refine remplissage techniques, we need to further explore issues such as the optimal distance between the 2 anchors (and hence the resultant tendon bridge) as this distance-along with the pliability of the tendon-potentially determines how much compression against the bone can be achieved. Furthermore, as remplissage techniques are proven to be effective in restoring shoulder stability and conferring successful clinical function, there is even more need for high-quality comparative studies to define their role versus that of more extensive open stabilization procedures. Mechanistic studies are also needed to define the fill-effect versus the possible check-rein and neuromuscular control activation components of remplissage.

Proprioception and neuromuscular control at return to sport after ankle surgery with the modified Broström procedure.

The modified Broström procedure (MBP) is an initial treatment for symptomatic chronic ankle instability (CAI) patients. This study aimed to compare the proprioception and neuromuscular control ability of both affected and unaffected ankles at the time of return to sports after MBP for patients with scores of normal controls. 75 individuals (40 who underwent MBP, 35 normal controls) participated. The dynamic balance test scores were significantly higher in the affected ankle of the patients than in the controls (1.5 ± 0.6° vs. 1.1 ± 0.4°, p < 0.003). The time to peak torque for dorsiflexion (60.8 ± 13.9 ms vs. 52.2 ± 17.5 ms, p < 0.022) and eversion (68.9 ± 19.1 ms vs. 59.3 ± 21.1 ms, p < 0.043) was significantly delayed in the affected ankle of the patients than in the controls. The dynamic balance test and time to peak torque in CAI patients remained significantly reduced at the time of return-to-sport after MBP. Clinicians and therapists should be aware of potential deficits in proprioception and neuromuscular control when determining the timing of return to sports after MBP.

Running gait biomechanics in females with chronic ankle instability and ankle sprain copers.

Limited evidence exists comparing running biomechanics between individuals with chronic ankle instability (CAI) and those who fully recover (copers). The purpose of this study was to simultaneously analyse running gait kinematics, kinetics, and surface electromyography (sEMG) between ankle sprain copers and individuals with CAI. Twenty-six (13 CAI, 13 Coper) recreationally active females participated and ran shod on an instrumented treadmill at 2.68 m/s. We assessed lower extremity kinematics and kinetics and sEMG amplitude for the fibularis longus, tibialis anterior, medial gastrocnemius, and gluteus medius muscles. Ten consecutive strides from the beginning of the trial were analysed using statistical parametric mapping (SPM) independent t-test. The CAI group had significantly more ankle inversion during 0-6%, 42-53%, and 96-100% of the running stride cycle compared to the coper group. At initial contact (0%), the CAI group was in an inverted ankle position (5.9°±6.8°) and the coper group was in an everted ankle position (-3.2°±5.5°; p = 0.01, d = 1.5). There were no significant differences identified for any other outcome measures. Increased ankle inversion during the swing phase leading into the loading phase is concerning because the ankle is in an open packed position and inversion is a primary mechanism of injury for sustaining a lateral ankle sprain.

Neuroplasticity Caused by Peripheral Proprioceptive Deficits.

PURPOSE: Proprioceptive feedback is crucial for motor control and stabilization of the shoulder joint in everyday life and sports. Shoulder dislocation causes anatomical and proprioceptive feedback damage that contributes to subsequent dislocations. Previous recurrent anterior shoulder instability (RSI) studies did not investigate functional neuroplasticity related to proprioception of the injured shoulder. Thus, we aimed to study the differences in neuroplasticity related to motor control between patients with RSI and healthy individuals, using functional magnetic resonance imaging, and assess the effects of peripheral proprioceptive deficits due to RSI on CNS activity. METHODS: Using passive shoulder motion and voluntary shoulder muscles contraction tasks, we compared the CNS correlates of proprioceptive activity between patients having RSI (n = 13) and healthy controls (n = 12) to clarify RSI pathophysiology and the effects of RSI-related peripheral proprioceptive deficits on CNS activity. RESULTS: Decreased proprioception-related brain activity indicated a deficient passive proprioception in patients with RSI (P < 0.05 family-wise error, cluster level). Proprioceptive afferent-related right cerebellar activity significantly negatively correlated with the extent of shoulder damage (P = 0.001, r = -0.79). Functional magnetic resonance imaging demonstrated abnormal motor control in the CNS during voluntary shoulder muscles contraction. CONCLUSION: Our integrated analysis of peripheral anatomical information and brain activity during motion tasks can be used to investigate other orthopedic diseases.

Changes in elbow joint contact area in symptomatic valgus instability of the elbow in baseball players.

The aim of this study was to evaluate the joint contact area of the dominant side and that of the non-dominant side without valgus instability in symptomatic pitchers. Ten symptomatic elbow medial ulnar collateral ligament (UCL) deficient baseball pitchers participated in this study. Computed tomography (CT) data from the dominant and non-dominant elbows were obtained with and without elbow valgus stress. The CT imaging data of each elbow joint were reconstructed using a 3D reconstruction software package, and the radiocapitellar and ulnohumeral joint contact areas were calculated. The center of the contact area and the translation from the position without stress to the position with valgus stress were also calculated. With elbow valgus stress, the contact area changed, and the center of the radiocapitellar joint contact area translated significantly more laterally in the dominant elbow than in the non-dominant elbow (p = 0.0361). In addition, the center of the ulnohumeral joint contact area translated significantly more posteriorly in the dominant elbow than in the non-dominant elbow (p = 0.0413). These changes in contact areas could be the reason for cartilage injury at the posterior trochlea in pitchers with UCL deficiency.

Reliability and usefulness of the single leg heel raise balance test in patients with chronic ankle instability.

We aimed to analyze the differences in static (including conventional and modified [single-leg heel-raise balance]) and dynamic postural stability and muscle endurance between patients with chronic ankle instability (CAI) and healthy controls, and to determine the reliability and usefulness of the single-leg heel-raise balance test in patients with CAI. In total, 26 patients with CAI and 26 healthy controls were enrolled. Postural stability was assessed using a postural stabilometry system. Muscle endurance was measured in dorsiflexion and plantarflexion using an isokinetic device. Modified static postural stability (P < 0.001) and dynamic postural stability (P < 0.001) were significantly poorer in the affected ankles of patients with CAI than in the controls. Plantarflexion endurance was significantly lower in the affected ankles of the patients with CAI than in the controls (P = 0.023). Modified static postural stability significantly correlated with plantarflexion endurance in both groups (CAI group: r = - 0.470, P = 0.015; healthy controls group: r = - 0.413, P = 0.036). Plantarflexion endurance was a significant risk factor for modified static postural stability in both the CAI group (R2 = 0.221, P = 0.015) and healthy controls (R2 = 0.170, P = 0.036). Given the reliability of the modified static postural stability test, clinicians and therapists should consider using it to assess improvements in postural stability and muscle endurance in patients with CAI before and after rehabilitation.