Posterior Tilt Angle Research Articles

Risk factors for nonunion in femoral neck fracture patients with internal fixation: A multicenter (TRON group) retrospective study

IntroductionFemoral neck fractures (FNFs) are common in elderly individuals. When minimally displaced, they are typically treated with internal fixation. Nonunion is a complication of internal fixation of FNF, that sometimes necessitates reoperation. Radiographic parameters, including the Pauwels angle and posterior tilt angle, are risk factors for nonunion. However, these parameters are assessed solely in a two-dimensional context. We developed a novel radiographic parameter named the “Kindex.” This multicenter investigation aimed to identify risk factors for nonunion following FNF fixation and evaluate the validity of this index. MethodsThis retrospective multicenter study collected data from 939 FNF patients who underwent internal fixation between 2016 and 2020 at 11 facilities (TRON group). The following exclusion criteria were applied: age <65, insufficient data, and Garden Stage III or IV fracture. Patient data, including age, sex, BMI, ASA classification, alcohol and smoking history, and comorbidities, were recorded. Radiographic measurements of the Pauwels angle and posterior tilt angle at the time of injury were used to calculate the Kindex. Correlations between the Pauwels angle, posterior tilt angle, Kindex, and nonunion were evaluated. A multivariate logistic regression analysis was performed to investigate independent risk factors for nonunion. A receiver operating characteristic (ROC) analysis was performed to determine the cutoff value of the Kindex, and the area under the curve (AUC) was calculated. ResultsThe study included 594 patients (males, n = 151; females, n = 443; average age, 80.9 years). Nonunion was observed in 13 cases (2.2 %). While the Pauwels angle and posterior tilt angle did not show significant correlations, the Kindex exhibited strong correlations with both parameters. In the multivariate analysis, the Kindex and renal impairment were independent risk factors for nonunion (Kindex: OR 1.06, p = 0.015; renal impairment: OR 1.48, p = 0.021). In the ROC analysis, a Kindex of 50 was identified as the optimal cutoff value (AUC 0.72). ConclusionThe nonunion rate after internal fixation of FNF was 2.2 %. Renal impairment and the Kindex were identified as independent risk factors. The Kindex at the time of injury may serve as a novel radiographic parameter to consider when evaluating the need for internal fixation in FNF cases.

The combined internal and external fixation surgery is effective and safe in treating posterior lateral tibial plateau fractures: An observational study.

To investigate the treatment outcomes of combined internal and external fixation surgery for patients with posterior lateral tibial plateau fractures and explore its safety. The study was conducted from February 2020 to February 2023 and included a total of 77 patients with Schatzker IV and Schatzker V type posterior lateral tibial plateau fractures. Patients were divided into control group and treatment group according to different treatment methods: the control group with 38 cases received treatment with dual-support plates, and the study group with 39 cases received treatment with internal fixation using medial plates combined with lateral locking plates. Clinical indicators during treatment, immediate postoperative and 12-month postoperative radiographic indicators, Rasmussen knee joint function scores before and 3 months after surgery, knee joint function recovery, quality of life, and postoperative complications were recorded and compared between the 2 groups. The inter-group comparisons were made for intraoperative blood loss, surgical duration, and the time to start weight-bearing postoperatively (P > .05). The study group had shorter postoperative hospital stays and fracture healing times compared to the control group (P < .05). Immediately postoperatively, the medial tilt angle and posterior tilt angle in both groups were compared (P > .05). At 12 months postoperatively, the medial tilt angle decreased and the posterior tilt angle increased in both groups compared to immediately postoperative values (P < .05), with no significant difference between the groups (P > .05). However, at 3 months postoperatively, the scores for various dimensions in both groups increased compared to preoperative values, and the study group had higher scores than the control group (P < .05). However, at 3 months postoperatively, the quality of life scores were higher than preoperative values in both groups, with the study group having higher scores (P < .05). The occurrence of complications during the treatment period was compared between the 2 groups (P > .05). The medial and lateral combined plate fixation has a good clinical effect in the treatment of posterolateral tibial plateau fractures, which can shorten the fracture healing time, help the recovery of knee joint function and improve the quality of life of patients after operation, and has high safety in the treatment process.

The efficacy of unicondylar knee arthroplasty for medial compartment arthritis of the knee combined with anterior cruciate ligament dysfunction

BackgroundTo investigate the outcome and prognosis after Unicondylar knee arthroplasty (UKA) in patients with medial compartment arthritis of the knee combined with anterior cruciate ligament(ACL) dysfunction.MethodsA total of 122 patients diagnosed with knee osteoarthritis and treated with medial mobile platform unicondylar replacement at our center from January 2019 to December 2021 were retrospectively included in the study, and were divided into two groups according to ACL function, namely the normal ACL function group (ACLF) and the poor ACL function (N-ACLF) group. The postoperative results and prognosis of the two groups were evaluated and compared.ResultsThis study included 122 patients who underwent UKA surgery. There were no statistical differences in preoperative and postoperative posterior tibial tilt angle, knee mobility, KOOS, and prognosis between the two groups (P > 0.05).ConclusionFor medial compartment arthritis of the knee combined with ACL malfunction, surgery resulted in pain relief, improved quality of life and a good prognosis for such patients. It is hoped that clinicians will perform UKA in patients with ACL dysfunction after a comprehensive evaluation to improve their quality of life.

Clinical study on the incidence of femoral head posterior tilt angle in non-displaced femoral neck fractures

To investigate the occurrence of posterior femoral head tilt after clinical non-displaced femoral neck fracture, and to provide a reference basis for clinical surgery and improvement of disease prognosis. Total of 165 patients with non-displaced femoral neck fractures of Garden typeⅠandⅡfrom January 2018 to June 2022 were selected as study subjects including 48 males and 117 females, with an average age of (71.5±8.5) years old ranging from 53 to 89, involving 97 cases of typeⅠand 68 of typeⅡ. On the patient's preoperative sagittal or axial CT film of the hip, the angle formed by the radius line of the femoral head and the midline of the femoral neck was used as the posterior tilt angle of the femoral head (α), and the posterior tilt femoral head angle was measured using the method proposed by Palm. The measured data were divided into 6 groups:α<0°, 0°<α< 5°, 5°≤α<10°, 10°≤α<15°, 15°≤α<20°, α≥20°, and the incidence of different ranges of posterior tilt angle was compared. The sex composition ratio of 165 patients were analyzed and compared, and the age of 65 was used as the cut-off point to compare the incidence of fractures between genders. Patients were divided into the posterior tilt <20° group for 135 cases and the posterior tilt ≥20°group for 30 cases according to the preoperative posterior tilt angle, the differences between two groups in terms of gender and age were analyzed. Among 165 patients with non-displaced femoral neck fractures, 143 cases with poaterior tilt of the femoral head occurred with an incidence of 86.7%. Posterior tilt 0°<α<5° accounted for 36 cases with an incidence of 21.8%;5°≤α<10° accounted for 40 cases with an incidence of 24.2%;10°≤α<15° accounted for 27 cases with an incidence of 16.4%;15°≤α<20° accounted for 10 cases with an incidence of 6.1%;posterior tilt angle α≥20° accounted for 30 cases, the incidence was 18.2%, of which the maximum posterior tilt angle was 42.7°. Statistical analysis showed that the percentage of fractures in the 165 patients selected for this study was significantly higher in female than in male, and that the female group was more likely to have fractures before the age of 65 years compared to the male group. However, gender, age and fracture subtypes (GardenⅠ, Ⅱ) were not influential factors for femoral neck fractures with a preoperative posterior femoral head tilt angle >20°(P>0.05). The incidence of femoral head posterior tile in non-displaced femoral neck fractures is relatively high, in which severe posterior tile occurs, and the femoral head posterior tile angle≥20° can reach 18.2%. In patients with closed reduction internal fixation, the fracture end needs to be repositioned as much as possible to reduce the risk of postoperative avascular necrosis of the femoral head. In order to prevent femoral neck fractures, special attention should be paid to anti-osteoporosis treatment for female. Preoperative assessment of posterior tilt is critical for patients of different ages, genders and fracture subtypes (GardenⅠ, Ⅱ).

Residual deformity after femoral neck fracture affects the location of osteonecrosis of the femoral head.

The localization of necrotic areas has been reported to impact the prognosis and treatment strategy for osteonecrosis of the femoral head (ONFH). Anteroposterior localization of the necrotic area after a femoral neck fracture (FNF) has not been properly investigated. We hypothesize that the change of the weight loading direction on the femoral head due to residual posterior tilt caused by malunited FNF may affect the location of ONFH. We investigate the relationship between the posterior tilt angle (PTA) and anteroposterior localization of osteonecrosis using lateral hip radiographs. Patients aged younger than 55 years diagnosed with ONFH after FNF were retrospectively reviewed. Overall, 65 hips (38 males and 27 females; mean age 32.6 years (SD 12.2)) met the inclusion criteria. Patients with stage 1 or 4 ONFH, as per the Association Research Circulation Osseous classification, were excluded. The ratios of anterior and posterior viable areas and necrotic areas of the femoral head to the articular surface were calculated by setting the femoral head centre as the reference point. The PTA was measured using Palm's method. The association between the PTA and viable or necrotic areas of the femoral head was assessed using Spearman's rank correlation analysis (median PTA 6.0° (interquartile range 3 to 11.5)). We identified a negative correlation between PTA and anterior viable areas (rho -0.477; p = 0.001), and no correlation between PTA and necrotic (rho 0.229; p = 0.067) or posterior viable areas (rho 0.204; p = 0.132). Our results suggest that residual posterior tilt after FNF could affect the anteroposterior localization of necrosis.

Accuracy of cup placement and pelvic motion in total hip arthroplasty in the lateral decubitus position using a new computed tomography-based navigation system with augmented reality technology.

This study aimed to investigate the accuracy of cup position and assess the changes in pelvic tilt during primary total hip arthroplasty (THA) in the lateral decubitus position using a new computed tomography (CT)-based navigation system with augmented reality (AR) technology. There were 37 cementless THAs performed using a CT-based navigation system with AR technology in the lateral decubitus position and 63 cementless THAs performed using manual implant techniques in the lateral decubitus position in this retrospective study. Postoperative cup radiographic inclination and anteversion were measured using postoperative CT, and the proportion of hips within Lewinnek's safe zone was analyzed and compared between the two groups. The mean absolute values of navigation error were assessed. Intraoperative pelvic tilt angles were also recorded using navigation system. The percentage of cups inside Lewinnek's safe zone was 100% in the navigation group and 35% in the control group (p < 0.001). The mean absolute values of navigation error in inclination and anteversion were 2.9° ± 2.1° and 3.3° ± 2.4°, respectively. The mean abduction angle of the pelvis was 5.1° ± 4.8° after placing the patients in the lateral decubitus position and 4.1° ± 6.0° after cup placement. The mean posterior tilt angle was 6.8° ± 5.1° after placing the patients in the lateral decubitus position and 9.3° ± 5.9° after cup placement. The mean internal rotation angle was 14.8° ± 7.4° after cup placement. There were no correlations between the navigation error in inclination or anteversion and the absolute values of changes of the pelvic tilt angle at any phase. Although progressive pelvic motion occurred in THA in the lateral decubitus position, especially during cup placement, the CT-based navigation system with AR technology improved cup placement accuracy.

The association between three-dimensional measurement of posterior tilt angle in impacted femoral neck fractures and osteonecrosis of the femoral head

BackgroundHollow screw internal fixation is commonly used in clinical treatment of impacted femoral neck fractures. Previous studies have demonstrated a correlation between the preoperative posterior tilt angle of the femoral head and failure of internal fixation, but there are fewer studies related to the occurrence of postoperative femoral head necrosis and the posterior tilt angle.MethodsTo examine the relationship between three-dimensional posterior tilt angle measurements in affected femoral neck fractures and postoperative osteonecrosis of the femoral head and related risk variables. We retrospectively examined 130 Yantaishan Hospital patients with affected femoral neck fractures from 2019 to 2022. Three-dimensional reconstruction technology assessed the posterior tilt angle of the femoral head and separated patients into necrosis and non-necrosis groups based on postoperative femoral head necrosis. Univariate analysis compared clinical data between groups, and multivariate logistic regression analyzed risk variables for femoral head necrosis. Postoperative femoral head necrosis was predicted by posterior tilt angle using Receiver operating characteristic (ROC) curve analysis.ResultsOut of 130 patients who were followed up for 16–68 months postoperatively, 20 developed femoral head necrosis. Multivariate logistic regression analysis indicated that the posterior tilt angle and reduction quality level C were risk factors for the occurrence of femoral head necrosis. The ROC curve analysis showed that the three-dimensional measurement of the posterior tilt angle had predictive value for postoperative femoral head necrosis, with a cut-off value of 20.6°.ConclusionsThese results suggest that, for patients with impacted femoral neck fractures, the posterior tilt angle and reduction quality level C are risk factors for femoral head necrosis following closed reduction and internal fixation surgery. Fracture patients with a posterior tilt angle ≥ 20.6°are more likely to experience postoperative femoral head necrosis.

Influence of scapular motion cues on trapezius muscle activity during Y exercise.

The Y exercise is a therapeutic exercise facilitating lower trapezius muscle activity. To identify the effects of scapular movement cues (posterior tilt vs. posterior tilt with adduction/depression) on trapezius muscle activity during Y exercise. Fifteen healthy men without current shoulder pain performed general Y exercise; Y exercise with cues for scapular posterior tilt; and Y exercise with cues for scapular posterior tilt, adduction, and depression. Electromyography (EMG) data for the trapezius muscles were collected during Y exercise. The posterior tilt angle of the scapula was measured in the prone position with and without cues for scapular posterior tilt using an inclinometer application. The greatest lower trapezius muscle activity was observed during Y exercise with cues for scapular posterior tilt, while the greatest EMG activity of the upper trapezius was observed during Y exercise with cues for scapular posterior tilt, adduction, and depression (p< 0.05). Middle trapezius muscle activity did not significantly differ among the three Y exercise conditions (p= 0.175). Cues for scapular posterior tilt significantly increased the scapular posterior tilt angle in the prone shoulder abduction position (p= 0.007). Cues for scapular posterior tilt were most effective in facilitating lower trapezius muscle activity during Y exercise.

What is the Fate of Undisplaced Femoral Neck Fractures Treated With Cannulated Screws?

BackgroundWe aimed to report implant survival in Garden type I and II femoral neck fractures treated with cannulated screws in elderly patients. MethodsWe retrospectively studied 232 consecutive unilateral Garden I and II patients (232 fractures) treated with cannulated screws. Mean age was 81 years (range, 65 to 100), and a body mass index of 25 (range, 15.8 to 38.3). No between-group differences were found in demographic variables and/or baseline measurements (P > .05). Mean follow-up was 36 months (range, 1 to 171). Two observers measured baseline radiographic variables with good-to-excellent interobserver reliability. The posterior tilt angle, measured on a cross-table lateral x-ray, was used to classify the cohort into <20° (n = 183) and ≥20° (n = 49). The cumulative incidence with competing risk analysis was used to predict association between posterior tilt and subsequent conversion to arthroplasty. Patient survival was calculated with the Kaplan-Meier estimate. ResultsImplant survival was 86.3% (95% confidence interval (CI) 80 to 90) at 12 months and 77.3% (95% CI 64 to 86) at 70 months. The 12-month cumulative incidence failure was 12.6% (95% CI 8 to 17). After controlling for confounders, posterior tilt ≥20° had higher risk of subsequent arthroplasty when compared to posterior tilt <20° (38.8 [95% CI 25 to 52] versus 5% [95% CI 2.8 to 9], subhazard ratio 8.3, 95% CI 3.8 to 18), without any other radiologic or demographic factor being associated with failure. Patient survival was 88.2% (95% CI 83 to 91.7) at 12 months, 79.5% (95% CI 73 to 84) at 24 months, and 57% (95% CI 48 to 65) at 70 months. ConclusionCannulated screws were a reliable treatment for Garden I and II fractures, except when there was posterior tilt ≥20°, where arthroplasty should be considered.

Effects of Mobile Phone Use on Gait and Balance Control in Young Adults: A Hip–Ankle Strategy

Background: This study aimed to derive the effects of walking while using a mobile phone on balance perturbation and joint movement among young adults. Methods: Sixteen healthy college students with no history of brain injury were tested. The participants were asked to walk under four different conditions: (1) walking, (2) browsing, (3) dialing, and (4) texting. Indicators related to balance control and lower limb kinematic/kinetic parameters were analyzed using the continuous relative phase and statistical nonparametric mapping methods. Results: Walking while using a mobile phone slowed participants’ gait speed and reduced the cadence, stride length, and step length. The posterior tilt angle (0–14%, 57–99%), torque of the hip flexion (0–15%, 30–35%, 75–100%), and angle of the hip flexion (0–28%, 44–100%) decreased significantly. The activation of biceps femoris and gastrocnemius, hip stiffness, and ankle stiffness increased significantly. This impact on gait significantly differed among three dual tasks: texting &gt; browsing &gt; dialing. Conclusion: Che overlap of walking and mobile phone use affects the gait significantly. The “hip–ankle strategy” may result in a “smooth” but slower gait, while this strategy was deliberate and tense. In addition, this adjustment also increases the stiffness of the hip and ankle, increasing the risk of fatigue. Findings regarding this effect may prove that even for young healthy adults, walking with mobile phone use induces measurable adjustment of the motor pattern. These results suggest the importance of simplifying the control of the movement.

Measurement of the normal contralateral hip flexion angle and posterior pelvic tilt angle using a pelvic guide pin in total hip arthroplasty

BackgroundWe aimed to measure the posterior pelvic tilt angle at maximum hip flexion and hip flexion range of motion at the femoroacetabular joint using a pelvic guide pin and to examine the difference in flexion range of motion when determined by a physical therapist and under anesthesia. MethodsData of 83 consecutive patients undergoing primary unilateral total hip arthroplasty were assessed. Using a pin inserted into the iliac crest to define the cup placement angle under anesthesia before and after total hip arthroplasty, the posterior pelvic tilt angle was determined as the change in pin tilt from the supine position to maximum hip flexion. Flexion range of motion under anesthesia was calculated as the difference in the angle between the trunk and thigh at maximum flexion and the posterior pelvic tilt angle. Flexion range of motion with a fixed pelvis measured preoperatively by a physical therapist was compared to that under anesthesia. A goniometer was used for all measurements and the number of measurements was one. FindingsMean posterior pelvic tilt angle of the pin inserted into the pelvis under anesthesia was 15.8° ± 5.3° (3°–26°) preoperatively and 12.1° ± 4.9° (3°–26°) postoperatively. Mean flexion range of motion under anesthesia was 109.4° ± 6.9° (88°–126°) and that measured by a physical therapist was 101.1° ± 8.2° (80°–120°); the difference was significant (9.7°; p < 0.01). InterpretationThese results highlight the difficulty in accurately determining hip flexion angles without the use of special devices and may help surgeons and physical therapists recognize and address this issue.

TWO-HOLE DYNAMIC HIP SCREW (DHS) FIXATION OF GARDEN I AND II NECK OF FEMUR FRACTURES: RADIOLOGICAL OUTCOMES AND PREDICTIVE FACTORS OF AVASCULAR NECROSIS

The aim of this study is to analyse the radiological outcomes and predictors of avascular necrosis following 2-hole DHS in Garden I and II neck of femur fractures in patients more than 60 years with a minimum follow up of one year.We retrospectively reviewed 51 consecutive patients aged more than 60 years who underwent DHS fixation for Garden I and II fractures. Demographics, fracture classification, time to surgery, pre-operative AMTS, preoperative posterior tilt angle, quality of reduction, pre and post-operative haemoglobin(hb), creatinine and comorbidities were analysed for correlation with AVN using Chi-Square test, Independent Sample and paired t test.There were 40 (78.4%) females and the mean age of the cohort was 77 years. 28 and 23 were Garden I and II NOF fractures respectively. Union was observed in all our patients except one(kappa =1). 12/51(23.5%) developed AVN of the femoral head. Statistically significant higher incidence of AVN was noted in patients with a pre-op tilt angle &gt; 200 (p = 0.006). The mean drop in Hb was higher in patients who developed AVN (21.5 g/L) versus the non-AVN group (15.9 g/L) (p = 0.001). There was no difference in AVN rates with respect to laterality, mean time to surgery, pre-op AMTS and Charlson comorbidity index. 4/52 (7.6%) had re-operations (one hardware prominence, two conversions to arthroplasty, one fixation failure during the immediate post-op period). The 30-day and one year mortality rates were 1.9 % and 11.7 % respectively.2-hole DHS fixation in undisplaced NOF fractures has excellent union rates. A pre-operative posterior tilt angle of &gt;200 and a greater difference in pre and post operative haemoglobin were found to correlate positively with the progression to AVN . No correlation was observed between AVN and time to surgery, laterality, quality of reduction and comorbidities.

Reliability of the assessment of scapular posterior tilt angle using the smartphone and scapular movement during arm elevation in healthy individuals and patients with frozen shoulder: a cross-sectional study.

Frozen shoulders are associated with abnormal scapular movements. However, scapular posterior tilt movement in frozen shoulders has not been investigated using simple clinical methods. This study aimed to clarify the reliability of scapular posterior tilting movement using a smartphone and scapular posterior tilting movement in healthy individuals and patients with frozen shoulder. The participants were 22 healthy young (age 25.9±4.1 years), 22 healthy middle-aged (age 52.6±4.4 years), and 37 individuals with frozen shoulder (age 56.0±7.0 years). Scapular posterior tilting movement was measured at shoulder flexion 0° (0° posterior tilt), shoulder flexion 90° (90° posterior tilt), and scapular tilt excursion using a smartphone. The intrarater reliability was calculated using the intraclass correlation coefficient (1, 3). Intrarater reliability at 0° posterior tilt and 90° posterior tilt was 0.76 and 0.84, respectively. The 0° posterior tilt was not significantly different among the three groups (P=.90). The 90° posterior tilt was not significantly different among the three groups (P=.06). The scapular tilt excursions were significantly greater in the frozen shoulder group than in the middle-aged group (P=.03). Measurement of scapular posterior tilting movement using a smartphone was highly reliable. The frozen shoulder might compensate for the limited arm elevation of the glenohumeral joint by scapular posterior tilting movement.

"In-Out-In" Percutaneous Reduction Technique for Treatment of Valgus-Impacted Femoral Neck Fractures: A Technical Trick and Case Series.

Valgus-impacted femoral neck fractures with or without posterior tilt of the femoral head are very common and full of pitfalls in clinical practice, which may lead to femoral neck shortening (FNS) and avascular necrosis (AVN). The study tries to introduce a novel technical trick aiming at anatomical reduction of valgus-impacted femoral neck fracture with minimally invasive procedure, and summarize the clinical prognosis in case series. In this retrospective study, 24 patients (seven men and 17 women) with valgus-impacted femoral neck fractures between May 2017 and July 2020 were managed by "in-out-in" percutaneous reduction technique (percutaneous reduction group). Another 24 cases (10 men and 14 women) suffering the fractures underwent in situ fixation were enrolled as control group for function comparison (in situ fixation group). All patients were followed up for 24-42months. The clinical outcomes included complications after operations (χ2 test) and Harris Hip Score (HHS) for hip function (unpaired t test) in the two groups. The radiographic outcomes were evaluated by collodiaphyseal angle, posterior tilt angle, and FNS before the operation and during the follow-up in the percutaneous reduction group (unpaired t test). Patients' preoperative data, including age, sex, affected side, fracture types, and medical history, were similar between the two groups, respectively (p > 0.05). After surgery, the mean HHS at 6, 12, and 24months were all better in the percutaneous reduction group (76 ± 6.72, 85.34 ± 6.33 and 90.54 ± 5.81) than that in the in situ fixation group (70.86 ± 6.91, 80 ± 6.11 and 84.1 ± 7.82), respectively (p < 0.05). One patient suffered fixation failure with screws retreat and one patient suffered AVN in the percutaneous reduction group. In the in situ fixation group, AVN occurred in two patients at last follow-up. There was no significant difference in complication amounts between the two groups (p > 0.05). In the percutaneous reduction group, collodiaphyseal angle, posterior tilt angle, and amount of FNS were significantly different between preoperative cases and immediately postoperative cases (p < 0.05). However, there was no statistical difference of the measurements among postoperative cases at different time points (within 24h, 6 months, and 2 years postoperatively) (p > 0.05). Our experience of the technique and the case series show that "in-out-in" percutaneous reduction technique for treatment of valgus-impacted femoral neck fracture with or without posterior tilt of the femoral head is safe and effective for achieving successful bone union and satisfactory function.

Effect of thoracic expansion restriction on scapulothoracic and glenohumeral joint motion during shoulder external rotation.

Shoulder external rotation in the throwing motion involves movement of the scapulothoracic and glenohumeral joints, thoracic spine, and the thorax. Restriction of thoracic expansion may decrease scapulothoracic joint motion and compensate by excessive glenohumeral joint motion. However, it is unclear how restricting the expansion of the thorax alters shoulder motion. To elucidate changes in scapulothoracic and glenohumeral joint movements caused by restricted thoracic expansion. Kinematic data were obtained using an electromagnetic tracking device (Liberty; Polhemus), from 18 male participants, during shoulder external rotation in the sitting position with and without restriction of thoracic expansion. The displacements from the start position to the maximum external rotation position were compared, and Pearson's correlation coefficient was calculated. A significant difference was observed in the scapulothoracic posterior tilt angle (P< 0.01) and glenohumeral external rotation angle (P< 0.01). A significant positive correlation existed between scapulothoracic posterior tilt and glenohumeral external rotation (P< 0.05) with and without restriction. Restriction of thoracic expansion decreased scapulothoracic motion and increased glenohumeral motion. Thus, a decrease in thoracic expansion may change scapulothoracic and glenohumeral movements, which may be a risk factor for throwing injuries.

Finite element analysis of necessity of reduction and selection of internal fixation for valgus-impacted femoral neck fracture

This study compared the biomechanical characteristics of different treatment strategies based on finite element analysis. Posterior tilt and valgus angle were measured on X-ray from ten valgus-impacted femoral neck fractures, and 7 finite element models that were generated to compare the stress and displacement. The results showed that in the intact femur, von Mises stress was concentrated at the medial and inferior sides of the femoral neck. In valgus-impacted femoral neck fractures, von Mises stress was at the same locations but was 5.66 times higher than that in the intact femur. When 3 cannulated screws were used for internal fixation, anatomic reduction diminished the stress at the fracture end from 140.6 to 59.14 MPa, although displacement increased from 0.228 to 0.450 mm. When the fracture was fixed with a sliding hip screw (SHS) + cannulated screw, there was less stress at the fracture end and greater displacement with anatomic reduction than that without reduction (stress: 15.9 vs 37.9 MPa; displacement: 0.329 vs 0.168 mm). Therefore, the SHS + cannulated screw has superior biomechanical stability than 3 cannulated screws, and is recommended following anatomic reduction to treat valgus-compacted femoral neck fractures.

Cannulated screw fixation for Garden I and II intracapsular hip fractures : five-year follow-up and posterior tilt analysis.

AimsIn UK there are around 76,000 hip fractures occur each year 10% to 15% of which are undisplaced intracapsular. There is considerable debate whether internal fixation is the most appropriate treatment for undisplaced fractures in older patients. This study describes cannulated hip screws survivorship analysis for patients aged ≥ 60 years with undisplaced intra-capsular fractures.MethodsThis was a retrospective cohort study of consecutive patients aged ≥ 60 years who had cannulated screws fixation for Garden I and II fractures in a teaching hospital between March 2013 and March 2016. The primary outcome was further same-side hip surgery. Descriptive statistics were used and Kaplan-Meier estimates calculated for implant survival.ResultsA total of 114 operations were performed on 112 patients with a mean age of 80.2 years (SD 8.9). The 30-day and one-year mortality were 1% (n = 1) and 13% (n = 15), respectively. Median follow-up was 6.6 years (interquartile range 6.0 to 7.3). Kaplan-Meier estimates showed a survivorship of 95% at one year and 90% at five years (95% confidence interval 84% to 95%) for cannulated screws. Nine patients underwent further hip surgery: four revision to total hip arthroplasty, one revision to hemiarthroplasty, three removals of screws, and one haematoma washout. Posterior tilt was assessable in 106 patients; subsequent surgery was required in two of the six patients identified with a posterior angle > 20° (p = 0.035 vs angle < 20°). Of the 100 patients with angle < 20°, five-year survivorship was 91%, with seven patients requiring further surgery.ConclusionThis study of cannulated hip screw fixation for undisplaced fractures in patients aged ≥ 60 years reveals a construct survivorship without further operation of 90% at five years. Cannulated screws can be considered a safe reliable treatment option for Garden I and II fractures. Caution should be taken if posterior tilt angle on lateral view exceeds 20°, due to a higher failure rate and reoperation, and considered for similar management to Garden III and IV injuries.Cite this article: Bone Jt Open 2022;3(3):182–188.

Nomogram for predicting reoperation following internal fixation of nondisplaced femoral neck fractures in elderly patients

ObjectiveWe aimed to evaluate risk factors and develop a nomogram for reoperation after internal fixation of nondisplaced femoral neck fractures (FNFs) in elderly patients.MethodsWe conducted a retrospective study involving a total of 255 elderly patients who underwent closed reduction and internal fixation with cannulated screw system for nondisplaced FNFs between January 2016 and January 2019. We collected data on demographics, preoperative radiological parameters, surgery, serum biochemical markers, and postoperative rehabilitation. In addition, we performed univariate and multivariate logistic regression analyses to determine independent risk factors for reoperation, and then developed a nomogram to assess the risks of reoperation. Besides, discriminative ability, calibration, and clinical usefulness of the nomogram were evaluated using the concordance index (C-index), the receiver operating characteristic (ROC) curve, calibration curve and decision curve analysis (DCA), respectively. We employed bootstrap method to validate the performance of the developed nomogram.ResultsOur analysis showed that among the 255 patients, 28 (11.0%) underwent reoperation due to osteonecrosis of the femoral head (14 cases), mechanical failure (8 cases) or nonunion (6 cases). All of the 28 patients underwent conversion surgery to arthroplasty. The multivariate logistic regression analysis demonstrated that preoperative posterior tilt angle ≥ 20°, Pauwel’s III type, younger patients, preoperative elevated levels of alkaline phosphatase (ALP), preoperative hypoalbuminemia, and early postoperative weight-bearing were independent risk factors for reoperation. In addition, the C-index and the bootstrap value of the developed nomogram was 0.850 (95% CI = 0.803–0.913) and 0.811, respectively. Besides, the calibration curve showed good consistency between the actual diagnosed reoperation and the predicted probability, while the DCA indicated that the nomogram was clinically valuable.ConclusionsOur analysis showed we successfully developed and validated a nomogram for personalized prediction of reoperation after internal fixation of nondisplaced FNFs in elderly patients. This model would help in individualized evaluation of the need for reoperation and inform strategies aimed at eliminating the need for the reoperation.

Effects of Intended Scapular Posterior Tilt Motion on Trapezius Muscle Electromyography Activity.

The intended scapular motion is a strategy to strengthen the lower trapezius (LT). However, few studies have explored the effects of the intended scapular posterior tilt motion on selective LT activation. Thus, the present study investigated the effect of the intended scapular posterior tilt on the electromyography (EMG) activity of trapezius muscles during prone shoulder horizontal abduction (PSHA). Eighteen asymptomatic men performed three types of PSHA: (1) preferred PSHA, (2) PSHA with the intended scapular posterior tilt, and (3) PSHA with the intended scapular posterior tilt and trunk extension. EMG activity of the upper trapezius (UT), middle trapezius (MT), and LT were measured during PSHAs. Scapular posterior tilt angle, with and without the intended scapular posterior tilt, were measured using inclinometer. The results indicated that LT muscle activity increased when scapular posterior tilt was applied with and without trunk extension (14–16%), compared to the preferred condition, during PSHA (p < 0.05). However, the addition of trunk extension to PSHA with the intended scapular posterior tilt increased the UT muscle activity (28%) and the UT/LT (29%) and UT/MT (31%) ratios (p < 0.05). The scapular posterior tilt angle was higher (15%) when applying the intended scapular posterior tilt (p = 0.020). These findings suggest that the intended scapular posterior tilt may be a useful strategy for selective LT muscle activation.

Scapular dyskinesis type is associated with glenohumeral joint and scapular kinematic alteration during pitching motion in baseball players

IntroductionScapular dyskinesis (SD) is associated with an increased risk of throwing-related shoulder injury onset, resulting in abnormalities in glenohumeral joint (GH) and scapular motions during pitching. The effects of SD on shoulder motion during pitching remain unknown. This study aimed to investigate kinematic alterations in GH and scapular motions during pitching in baseball players with type I SD. MethodsSixty-seven university and independent-league baseball players with and without SD were included. Pitching motion was measured using an optical three-dimensional motion capture system, and a SD test was conducted to evaluate SD. SD was classified into types I–IV. The inter-rater reliability of SD assessment was calculated using kappa coefficients. Three-dimensional GH and scapular kinematics during pitching motion were analyzed. ResultsThe percentage of agreement representing the inter-rater reliability of SD assessment was 77.6% (52/67; kappa coefficient: 0.72). Overall, 24 and 27 participants were categorized into abnormal (type I SD) and normal group (type IV SD), respectively, with normal scapular motion; one individual with type III SD was excluded. The abnormal group exhibited a significantly increased GH external rotation angle (9°) and decreased scapular posterior tilt angle (6°) during the maximum external rotation period compared with the normal group. ConclusionsBaseball players in the abnormal group showed increased GH motion and decreased scapular motion during pitching. The SD test for the evaluation of type I SD can help predict excessive GH external rotation and decreased scapular posterior tilt during pitching.