Femoral Neck Shaft Angle Measurement for Differentiating Femoral Head Stress Fracture from Avascular Necrosis.

OBJECTIVE: The study aimed to evaluate whether the measurement of Femoral Neck Shaft Angle (FNSA) can be helpful in differentiating femoral head Stress Fracture (SF) from Avascular Necrosis (AVN). METHODS: From September 2019 to April 2022, sixty-four patients [median age 32.0 years, interquartile range (IQR) 23.0-39.0 years] who underwent both hip radiograph and Magnetic Resonance Imaging (MRI) and diagnosed as femoral head SF or AVN were included in our retrospective study. Patients were divided into as having either femoral head SF (n = 34) or AVN (n = 30). The FNSA was measured in anteroposterior hip radiography. Continuous values were compared using the Mann-Whitney U test. The assessment of the predictive value of FNSA for femoral head SF was performed by Receiver Operating Characteristic (ROC) analysis. RESULTS: The FNSA was significantly higher in patients with SF (median 133.5°, IQR 128.0-136.7°) than those with AVN (median 127.5°, IQR 124.0-132.0°) (p = 0.001). In addition, the FNSA was significantly higher in SF femurs (median 134.8°, IQR 129.2-137.4°) than in contralateral normal femurs (median 127.1°, IQR 124.3-132.5°) in patients with unilateral femoral head SF (n = 30) (p < 0.001). In ROC analysis, the sensitivity, specificity, and Area Under the Curve (AUC) for predicting the femoral head SF were 77.3%, 63.3%, and 0.785 (95% confidence interval: 0.666-0.905), respectively, at a cutoff of 130.2°. CONCLUSION: Increased FNSA was associated with femoral head SF; thus, measurement of FNSA could be helpful for differentiating femoral head SF from AVN.

Stemless reverse shoulder arthroplasty neck shaft angle influences humeral component time-zero fixation and survivorship: a cadaveric biomechanical assessment.

Background: Stemless humeral components are being clinically investigated for reverse shoulder arthroplasty (RSA) procedures. There is, however, a paucity of basic science literature on the surgical parameters that influence the success of these procedures. Therefore, this cadaveric biomechanical study evaluated the neck shaft angle (NSA) of implantation on the survivability and performance of stemless RSA humeral components during cyclical loading. Methods: Twelve paired cadaveric humeri were implanted with stemless RSA humeral components at NSAs of 135° and 145°. Implant-bone motion at the periphery of the implant was measured with 3 optical machine vision USB3 cameras outfitted with c-mount premium lenses and quantified with ProAnalyst software. A custom 3-dimensional loading apparatus was used to cyclically apply 3 loading directions representative of physiological states at 5 progressively increasing loading magnitudes. Stemless 135° and 145° implants were compared based on the maximum implant-bone relative distraction detected, as well as the survivorship of the implants throughout the loading protocol. Results: Primary fixation and implant biomechanical survivorship were substantially better in the 145° NSA implants. The 135° NSA implants elicited significantly higher implant-bone distractions during cyclical loading (P = .001), and implant survivorship was considerably lower in the 135° NSA specimens when compared to the 145° NSA specimens (135° NSA: 0%, 145° NSA: 50%) (P < .001). Conclusion: NSA is a modifiable parameter that influences time-zero implant stability, as well as the early survivorship of the stemless RSA humeral components tested in this study. NSA resections of 145° appear to promote better stability than those utilizing 135° NSAs during early postoperative eccentric loads. Further studies are required to assess if other stemless reversed humeral implant designs have improved time-zero fixation at higher NSAs.

Hip Axis Length and Femoral Neck-Shaft Angle as Risk Factors for Proximal Femur Fractures in Octogenarians to Centenarians.

(1) Background: The prevention of proximal femoral fractures among people of very advanced age is relevant as they are common and increasing in number. The aim of this study was to determine if the hip axis length (HAL) and the neck-shaft angle (caput-collum-diaphyseal CCD) are risk factors for those fractures among people aged 80 years and over. Consequently, it was additionally analysed if these parameters are associated with a certain fracture type. (2) Methods: Anteroposterior radiographs of the pelvis were collected to form three groups (femoral neck fractures (FNFx), trochanteric fractures (TFx) and non-fractured femora (NFx)). Two independent blinded observers separately conducted each measurement of the HAL and CCD. Statistical analysis was performed to determine the association between the measured parameters and type of fracture. (3) Results: One hundred and fifty patients (50 per group) were examined, of which the mean age was 92.7 ± 3.5 (range 81-104) years. Both the HAL and CCD of the FNFx group were significantly larger than in the TFx group (p = 0.013, 0.003). The CCD was higher in the FNFx than that of the NFx group (p = 0.001). No further significant differences of HAL and CCD were observed between the groups. (4) Conclusions: For people aged 80 years and over, an increased HAL represented no risk factor for proximal femur fractures, and a large HAL was associated with an increased occurrence of FNFx instead of TFx. A large CCD was associated with an increased risk of suffering a femoral neck fracture, showing evidence of the CCD being a risk factor for the extremely old population.

A Comparison of the Clinicoradiological Outcomes of Intertrochanteric Fractures Treated Using Proximal Femoral Nail and Proximal Femoral Nail Anti-rotation.

Background Managing intertrochanteric fractures presents challenges for orthopedic surgeons, not only in fixing the fracture but also in preventing and managing associated complications, especially in the vulnerable geriatric population. Cephalomedullary nails are commonly used for surgical fixation due to their favorable functional profile, which preserves the hip's abductor lever arm and proximal femur anatomy. However, there's a lack of data comparing two major options: proximal femoral nail (PFN) and proximal femoral nail anti-rotation (PFNA). This study aimed to compare the radiological fracture reduction and fixation as well as functional outcomes of these two implants in treating intertrochanteric fractures. Methods The study, spanning 24 months, involved a prospective comparative design. Participants included patients diagnosed with intertrochanteric femur fractures classified as AO Type 31 A1, AO Type 31 A2, and AO Type 31 A3. Fifty patients were evenly distributed into PFN and PFNA groups. Preoperatively, clinical and radiological assessments were conducted, along with serum vitamin D level measurements. Surgeries, performed under anesthesia with image intensifier guidance, followed defined reduction and implant insertion protocols for each group. Postoperatively, evaluations were conducted up to six months, examining parameters such as tip-apex distance (TAD), Cleveland index, and modified Harris hip score, while documenting intraoperative duration and blood loss. Data analysis utilized the statistical software Statistical Package for Social Sciences (SPSS), version 22.0 (IBM Corp., Armonk, NY), employing descriptive statistics, chi-square tests, independent t-tests, and paired t-tests, with significance set at p < 0.05. Results In our study, 50 patients were enrolled, with equal gender distribution (64.0% male, 36.0% female, p=1.000). The mean ages in the PFN and PFNA groups were 66.2 ± 9.8 years and 66.4 ± 11.3 years, respectively (p=0.936). All fractures united by six months, with no implant-related complications reported. PFNA showed significantly lower blood loss and shorter surgery durations (p<0.001). TAD and neck shaft angle were similar between groups (p=0.826, p=0.555). Cleveland index placement and modified Harris hip score improvement were comparable (p=0.836, p<0.001). Predominant vitamin D deficiency was observed in both groups. Conclusion PFNA offers measurable intraoperative benefits over conventional PFN in terms of operative time, blood loss, and need for fluoroscopic imaging. However, no statistically observable benefits were noted in postoperative functional outcomes or complications between the two implants.

Biomechanics of a collum-fixated short stem in total hip arthroplasty.

Background: Biomechanical reconstruction of the hip significantly impacts the clinical outcome and implant survival. Our knowledge is limited of the ability of neck-stabilised prostheses to restore hip biomechanics. We hypothesised that hip biomechanics, specifically leg length and global offset (GO), may be restored to an acceptable range using the Primoris™ stem. Methods and material: In this retrospective study, we analysed 152 patients who underwent total hip replacement (THA) using the short collum-fixated stem Primoris™.The primary outcomes were hip parameters measured by x-ray following THA using the Primoris™ stem. After surgery, the biomechanical parameters used were measured at the arthroplasty and the native contralateral side of the same x-ray. The X-rays were taken one year after the patient's surgery.1. GO.2. Leg length discrepancy (LLD).3. Neck shaft angle (NSA). Results: We recorded an average GO of -3.4 mm (standard deviation (SD) 7.2) and an average LLD of +3.8 mm (SD 6.4). Furthermore, we registered an average 14-degree NSA increase (SD 7.4). Conclusion: The Primoris™ neck-stabilised stem enabled hip anatomy restoration to a favourable range with respect to GO and LLD as the average difference fell within ±5 mm. However, the stem tended to be implanted in valgus.

Humeral head size predicts baseplate lateralization in reverse shoulder arthroplasty: a comparative computer model study.

Background: In reverse shoulder arthroplasty (RSA), the ideal combination of baseplate lateralization (BL), glenosphere size (GS), and glenosphere overhang (GOH) with a commonly used 145° neck shaft angle (NSA) is unclear. This is the first study evaluating correlations of body height (BH), humeral head size (HS), glenoid height (GH), and association of gender with best glenoid configurations for range of motion (ROM) maintaining anatomic lateralization (aLAT) for optimized muscle length in 145° and less distalized 135° RSA. Methods: In this computer model study, 22 computed tomographies without joint narrowing were analyzed (11 male/female). A standardized semi-inlay 145° platform stem was combined with 20 glenoid configurations (baseplate [B] 25, 25 + 3/+6 lateralized [l], 29, 29 + 3/6l combined with glenosphere 36, 36 + 2 eccentric [e], 36 + 3l, 39, 39 + 3e, 39 + 3l , 42, 42 + 4e). Abduction-adduction, flexion-extension, external rotation-internal rotation, total ROM (TROM), and total notching relevant (TNR) ROM were computed, best TROM models respecting aLAT (-1 mm to +1 mm) and HS/GH recorded. Second, the 145° models (Ascend Flex stem; Stryker, Kalamazoo, MI, USA) were converted and compared to a 135° inlay RSA (New Perform stem; Stryker, Kalamazoo, MI, USA) maintaining GOH (6.5-7 mm) and aLAT. Results: Best 145° models had eccentric glenospheres (mean BL: 3.5 mm, GOH 8.8 mm, GS 38.1 mm, distalization 23 mm). The 135° models had concentric glenospheres, mean BL 3.8 mm, GOH 6.9 mm, GS 39.7 mm, and distalization 14.1 mm. HS showed the strongest positive correlation with BL in 145° and 135° models (0.65/0.79). Despite reduced GOH in smaller females with a 135° NSA, adduction, external rotation, extension, TNR ROM, and TROM were significantly increased (P = .02, P = .005, P = .005, P = .004, P = .003), abduction however reduced (P = .02). The same trends were seen for males. Conclusion: HS is a practical measure in surgery or preoperatively, and the strong positive correlation with BL is a useful planning aid. Despite reduction of GOH, conversion to a less distalized 135° NSAinlay design is powerful to maintain and even significantly increase all components of TNR ROM (extension/external rotation/adduction) in small females with the drawback of reduced abduction which may however be compensated by scapula motion. Lateralization with a less distalized 135° RSA optimizes muscle length, may facilitate subscapularis repair, and maintains highest rigid body motion.

Does early stable fixation reduce complications in paediatric femoral neck fractures?

The primary objective of this study was to juxtapose the union rate and incidence of complications in paediatric patients presenting early (≤ 7 days) following injury with children presenting later (> 7 days) with femoral neck fractures. This critical appraisal evaluated 15 patients according to their timing of presentation and surgery from the initial day of injury (Group A: operated ≤ 7 days or Group B: > 7 days of injury). Patients with traumatic femoral neck fractures with Delbet 1 to 4 subtypes who were skeletally immature (age ≤ 16 years) were included in the study. Pathological fractures and post-infective fractures were not included. Each patient's secondary loss of reduction was calculated by measuring the Neck shaft angle (NSA) on the immediate post-operative radiograph and at the union. A change in NSA of ≥ 5 degrees was considered a significant loss of reduction. Ratliff's Criteria was used to analyze the final result, and a thorough record of complications was kept. There were no significant variations in the two groups' with respect to distributions of age, sex, injury mechanism, or fracture pattern. The most frequent injury culprit in both groups was falling from a height. Type II fracture pattern (54.54%) was more common in group A, while Type III and Type II fracture pattern was equally distributed in group B. In group A, the mean operation time was 55 ± 8.25 minutes, whereas in group B, it was 65 ± 15 minutes (p-value > 0.05). In group A, 90.9% of patients underwent CCS fixation, and in group B, 75% underwent fixation by CCS. The quality of reduction in post-operative radiographs was anatomical in 10 (90.9%) patients and unacceptable in 1 (9.1%) patient. In group B, 2 (50%) patients had an anatomical reduction, while 2 (50%) patients had an unacceptable reduction. Timing of reduction and its association with complications showed that early stable reduction and fixation decrease the occurrence of complications in femoral neck fractures (p-value = 0.033). Fracture union was seen in all our patients in both groups and none of our patients underwent non-union. The mean union time was 11.11 ± 7.06 weeks in group A and 16.5 ± 2.59 weeks in group B (p-value = 0.0189). In group A, only 1 (9.1%) patient developed coxa vara. In group B, out of 4 patients, the femoral head of one patient underwent avascular necrosis, one patient exhibited coxa vara, and 1 patient developed premature physeal closure with limb length inequality. Management of femoral neck fractures in children is challenging because of the paediatric bone's peculiar anatomic and physiological considerations. In our study, patients operated within 7 days developed fewer complications as compared to patients who were operated after 7 days, which was statistically significant. Although AVN is a frequent adverse consequence of pediatric femoral neck fractures, early reduction and stable fixation lowers AVN rates, as observed in our study. Our short-term functional and radiological results using the Ratliff scoring system were comparable to previous studies owing to stable anatomic reduction. Based on our findings and the existing literature, we emphasize long-term follow-up and recommend an early stable anatomic reduction in the treatment of paediatric femoral neck fractures.

Are there associations between hip geometry and bone quality? An analysis on 3074 adults from a general population.

INTRODUCTION: Patients with reduced bone mineral density and altered hip geometry are susceptible for hip pathologies. Knowledge on associations between bone properties and hip geometric parameters might facilitate identification of patients at risk for hip pathologies. The aim of the present study was to identify associations of bone properties assessed by quantitative ultrasound (QUS) at the heel and hip geometric parameters like center-edge angle (CE), neck-shaft angle (NSA) and alpha angle. MATERIALS AND METHODS: Hip geometric parameters (CE, NSA and alpha angle) of 3074 participants from the population-based Study of Health in Pomerania were assessed on magnetic resonance imaging. QUS was performed on both calcanei providing broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness-index. Based on the stiffness-index the individual osteoporotic fracture risk (low, moderate or high) was determined. Associations between QUS-based and hip geometric parameters were calculated in linear regression models adjusted for age, sex, body height and weight. Interactions of QUS markers with age and sex on hip geometric parameters were tested. RESULTS: Significant inverse associations between BUA (ß = - 0.068), SOS (ß = - 0.024) as well as stiffness-index (ß = - 0.056) and CE were present, while fracture risk was positively associated with CE (ß for high = 1.28 and moderate = 2.54 vs. low fracture risk). Interactions between BUA and sex as well as between SOS and age were detected in the models for CE. Furthermore, there was an inverse relation between fracture risk and NSA that was restricted to the moderate risk (ß for moderate vs. low fracture risk = - 0.60). There were no significant associations between QUS parameters and alpha angle. CONCLUSIONS: In the general population, several associations between QUS-based bone properties or fracture risk and hip geometry are present. Less dysplastic hips had a lower stiffness-index and a higher fracture risk, whereas more valgus hips had a lower fracture risk.

Medium-term clinical and radiographic outcomes of a cementless prosthesis with a 140° neck-shaft angle in reverse total shoulder arthroplasty.

BACKGROUND: The design of humeral implants has evolved from the initial Grammont design, notably regarding the neck-shaft angle (NSA) and through the use of cementless prostheses. Stress shielding was frequently reported with cementless implants, the 2 main risk factors being humeral stem misalignment and high filling ratios. Our hypothesis was that standard length cementless stems with an NSA of 140° would facilitate good alignment with moderate filling ratios, thereby limiting stress shielding and ensuring good clinical outcomes. METHODS: A single-center retrospective study was conducted of patients who underwent reverse total shoulder arthroplasty between January 2015 and August 2017, with at least 2 years' follow-up. Clinical evaluations included range of motion measurements and Constant and subjective shoulder values scores. Frontal alignment was assessed in terms of the angle (α) between axes of the stem and of the humerus. Filling ratios were measured in the metaphysis of the humerus, in the diaphysis, and at the distal end of the stem and considered excessive above 0.7. Stress shielding was evidenced radiographically by the observation of medial cortical narrowing, medial metaphysis thinning, lateral metaphysis thinning or under-the-baseplate osteolysis. RESULTS: Eighty-two shoulders were included and 70 had radiographic follow-up data available. The mean patient age was 78 years and 63/81 patients (78%) were female. The mean follow-up time was 39 ± 7 months. The mean α angle was 1.4° ± 0.9° and was less than 5° in all cases. The mean metaphyseal, diaphyseal, and distal filling ratios were 0.61 ± 0.06, 0.70 ± 0.08, and 0.64 ± 0.09, respectively. The mean Constant score improved from 28 ± 11 preoperatively to 64 ± 14 at last follow-up. The mean subjective shoulder values score at last follow-up was 81 ± 12. Seventy-nine percent of patients (55/70) had at least 1 form of stress-shielding related, which were not associated with clinical outcomes, apart from lateral metaphysis thinning, which was associated with lower active anterior elevation (mean, 106° ± 30° vs. 126° ± 28°; P = .01) and lower Constant scores (mean, 56 ± 17 vs. 65 ± 14; P = .06). CONCLUSION: The use of cementless reverse shoulder prostheses with a NSA of 140° was associated with good clinical outcomes at 2 years' follow-up. The prosthesis stem was correctly aligned with the humeral axis and the filling ratios were <0.7 in all cases. Stress-shielding was common but, apart from lateral metaphysis thinning, this had no impact on clinical outcomes.

The effect of subscapularis repair in reverse total shoulder arthroplasty depends on the design of the implant: a comparative study with a minimum 2-year follow-up.

INTRODUCTION: The role of the subscapularis (Ssc) tendon does not yet have a well-defined role in RSA. The purpose of the present study was to evaluate if the repair of the Ssc in RSA improves overall clinical and radiographic results and if it has the same results using a medialized design humeral stem compared to a lateralized design. METHODS: Eighty-four consecutive patients undergoing RSA were retrospectively analyzed. Nine patients were lost at FU. Two implants with similar glenosphere design and different stem design (medialized and lateralized) were used. The Ssc was repaired in case of good quality of the fibers and reducibility without tension intraoperatively. Patients were divided into four groups for data analysis depending on whether they had received a medialized or lateralized design and Ssc repair or not. Patients were reviewed at an average follow-up of 40.8 ± 13.1 months. Clinical outcome measures included Active range of motion (ROM), strength, visual analog scale (VAS), Constant-Murley score (CMS), and the American Shoulder and Elbow Surgeons score (ASES). Radiographic evaluation at final follow-up was performed to assess scapular notching, stress shielding, and radiolucent lines. RESULTS: No statistically significant clinical differences (p > 0.05) emerged between Lat/Ssc+ and Lat/Ssc-. Conversely, the patients belonging to the Med/Ssc- group reported statistically worse (p < 0.05) results than the Med/Ssc + group in terms of VAS, ASES and CMS. Statistically worse (p < .05) results in the Med/Ssc- group than in the Med/Ssc + were found also in active ROM achieved in FE, ABD, ER1 and ER2, and in the strength obtained in FE, ABD and ER2. Scapular notching was reported in 3 shoulders (15.7%) in Lat/Ssc+ group and in 7 shoulders (50%) in Lat/Ssc- group, while it was reported in 4 shoulders (14.2%) in Med/Ssc + group and in 6 shoulders (42.8%) in Med/Ssc- group. Stress shielding was observed in 6 cases in Lat/Ssc+ group (31.6%), in 8 cases in Lat/Ssc- group (57.1%), in 3 cases (10.7%) in Med/Ssc + group and 4 cases in Med/Ssc- group (28.6%). CONCLUSIONS: Patients undergoing RSA show clinical improvements at mid-term follow-up with a low rate of complications, regardless of the use of a medialized or a lateralized humeral stem design. Ssc repair is associated with better functional outcomes in the cohort of medialized stem, while it did not yield significant differences in the cohort of lateralized stem. LEVEL OF EVIDENCE: Level III; Retrospective Cohort Comparison; Treatment Study.

Lateralization and distalization shoulder angles do not predict outcomes in reverse shoulder arthroplasty for cuff tear arthropathy.

BACKGROUND: In reverse shoulder arthroplasty (RSA), there are a plethora of measurements regarding implant lateralization and distalization to optimize the center of rotation. Two specific measurements known as the "lateralization shoulder angle" (LSA) and "distalization shoulder angle" (DSA) have been the recent focus of studies to assess their association with RSA and postoperative function. The aim of this study was to evaluate the prognostic clinical value of the LSA and DSA in a large cohort of patients with cuff tear arthropathy (CTA) who were treated with different RSA systems. METHODS: Two local shoulder arthroplasty registries were reviewed for all RSA patients documented to have undergone a radiologic assessment and complete 2-year follow-up examination. The main inclusion criterion was primary RSA in patients with CTA. Patients with either a complete teres minor tear, os acromiale, or acromial stress fracture reported between the time of surgery and the 24-month follow-up were excluded. Five RSA implant systems with 4 neck-shaft angles (NSAs) were assessed. The Constant score, Subjective Shoulder Value, and range of motion at 2 years were correlated with both the LSA and DSA assessed on 6-month anteroposterior radiographs. Linear and parabolic univariable regressions were calculated for both shoulder angles, for each prosthesis system, and for the entire patient cohort. RESULTS: Between May 2006 and November 2019, there were a total of 630 CTA patients who had undergone primary RSA. Of this large cohort of patients, 270 were treated with the Promos Reverse prosthesis system (NSA, 155°); 44, Aequalis Reversed II (NSA, 155°); 62, Lima SMR Reverse (NSA, 150°); 25, Aequalis Ascend Flex (NSA, 145°); and 229, Univers Revers (NSA, 135°). The mean LSA was 78° (standard deviation [SD], 10°; range, 6°-107°), and the mean DSA was 51° (SD, 10°; range, 7°-91°). The average Constant score at 24 months' follow-up was 68.1 points (SD, 13 points; range, 13-96 points). Neither the linear nor parabolic regression calculations for the LSA or DSA revealed significant associations with any of the clinical outcomes. CONCLUSION: Different patients may achieve different clinical outcomes despite having identical LSA and DSA values. There is no association between angular radiographic measurements and 2-year functional outcomes after RSA.

Stemless reverse humeral component neck-shaft angle has an influence on initial fixation.

BACKGROUND: Stemless anatomic humeral components are commonly used and are an accepted alternative to traditional stemmed implants in patients with good bone quality. Presently, little literature exists on the design and implantation parameters that influence primary time-zero fixation of stemless reverse humeral implants. Accordingly, this finite element analysis study assessed the surgical implantation variable of neck-shaft angle, and its effect on the primary time-zero fixation of reversed stemless humeral implants. METHODS: Eight computed tomography-derived humeral finite element models were used to examine a generic stemless humeral implant at varying neck-shaft angles of 130°, 135°, 140°, 145°, and 150°. Four loading scenarios (30° shoulder abduction with neutral forearm rotation, 30° shoulder abduction with forearm supination, a head-height lifting motion, and a single-handed steering motion) were employed. Implantation inclinations were compared based on the maximum bone-implant interface distraction detected after loading. RESULTS: The implant-bone distraction was greatest in the 130° neck-shaft angle implantation cases. All implant loading scenarios elicited significantly lower micromotion magnitudes when neck-shaft angle was increased (P = .0001). With every 5° increase in neck-shaft angle, there was an average 17% reduction in bone-implant distraction. CONCLUSIONS: The neck-shaft angle of implantation for a stemless reverse humeral component is a modifiable parameter that appears to influence time-zero implant stability. Lower, more varus, neck-shaft angles increase bone-implant distractions with simulated activities of daily living. It is therefore suggested that humeral head osteotomies at a higher neck-shaft angle may be beneficial to maximize stemless humeral component stability.

Age-related Changes with the Trabecular Bone of Ward's Triangle and Neck-shaft Angle in the Proximal Femur: A Radiographic Study.

OBJECTIVE: The Ward triangle is an important area used clinically to diagnose and assess osteoporosis and its fracture risk in the proximal femur. The main objective of this study was to investigate the rules of development and maturation of the trabeculae of Ward's triangle to provide a basis for the prevention and treatment proximal femur fracture. METHODS: From January 2018 to December 2019, individuals from 4 months to 19 years old who underwent hip growth and development assessments at the Third Hospital of Hebei Medical University were selected retrospectively. The outpatient electronic medical record system was used to collect information such as age, gender, imaging images, and clinical diagnosis. The development score and maturity characteristics of the trabecular bone were analyzed using hip radiograph data. Correlation analysis was performed to identify the relationship among age, neck-shaft angle and development and maturity score of the trabecular bone. RESULTS: A total of 941 patients were enrolled in this study, including 539 males and 402 females. Primary compression trabeculae were all present at 1 year of age and matured at 7 years of age and older; primary tension trabeculae were all present at 4 years of age and matured at 18 years of age. Secondary compression trabeculae were present at 4 years of age and matured at 18 years of age. In addition, the neck-shaft angle progressively decreases from 4 months to 14 years of age but barely changes between 15 and 19 years of age. CONCLUSION: In short, the development and maturation of the trabeculae in the ward' triangle followed a specific temporal pattern that was related to the neck-shaft angle. Therefore, these findings can help us understand structure and mechanical characteristics of proximal femoral trabeculae, and improve our understanding of the mechanism and treatment of proximal femoral fractures.

Impact of aberrant beam paths on antero-posterior shoulder radiographs in proximal humeral fractures.

INTRODUCTION: Accurate radiographic assessment of proximal humeral fractures (PHF) is important as it influences clinical decision-making and predicts clinical outcome. Since aberrant radiographic views might influence the assessment of fracture displacement, it was the goal of this study to investigate the impact of aberrant beam paths on radiographic assessment of PHF. MATERIALS AND METHODS: Ten consecutive patients with a displaced PHF, bilateral computed tomography (CT) scan, and a true clinical AP radiograph were included. Digitally reconstructed radiographs (DRRs) were generated and aberrant beam paths were simulated by rotation of ± 30° around the horizontal (flexion and extension) and vertical axis (internal and external rotation) by increments of 10°. Measurement of the neck-shaft-angle (NSA) and eccentric head index (EHI) addressed humeral angulation and offset, respectively. Paired comparisons determined the influence of aberrant beam paths on both measurements between incremental altered views, and between clinical and digital true AP views. Descriptive statistics assessed the change in Neer classification and recommended treatment. RESULTS: True AP DRRs approximated the clinical true AP view by a mean difference of 2° for NSA, and a mean difference of 0.12 for EHI. NSA in injured shoulders was most susceptible to malrotation around the vertical axis (p < 0.03), with largest differences seen for internal rotation. Aberrant projections in extension had no influence on NSA (p > 0.70), whereas flexion of ≥ 20° and 30° demonstrated differences in injured and uninjured shoulders, respectively (p < 0.05). EHI was only influenced by malrotation in internal rotation in uninjured shoulders (p < 0.03). Alterations in Neer type occurred at 30° of malrotation in 5 cases, with a change in recommended treatment in 2. CONCLUSIONS: Humeral angulation and offset measurements on AP radiographs are more susceptible to aberrant beam paths in fractured humeri. Altered radiographic beam paths around the vertical axis showed the most substantial influence on the assessment of PHF, with angular measurements demonstrating larger differences then offset measurements. Beam path alterations of 30° can influence the Neer classification, and might influence fracture displacement-based decisions.

Effect of Total Hip Arthroplasty on Ipsilateral Lower Limb Alignment and Knee Joint Space Width: Minimum 5-Year Follow-up.

BACKGROUND: This study aimed to 1) assess the effect of total hip arthroplasty (THA) on coronal limb alignment, namely, the hip-knee-ankle angle (HKA), 2) identify factors that determine changes in the HKA, and 3) determine whether alignment changes influence the knee joint space width. METHODS: We retrospectively evaluated 266 limbs of patients who underwent THA. Three types of prostheses with neck shaft angles (NSAs) of 132°, 135°, and 138° were used. Several radiographic parameters were measured in the preoperative and final radiographs (at least 5 years after THA). A paired t-test was used to confirm the effect of THA on HKA change. Multiple regression analysis was performed to identify radiographic parameters related to HKA changes following THA and changes in knee joint space width. Subgroup analyses were performed to reveal the effect of NSA change on the HKA change, and the proportion of total knee arthroplasty usage and changes in radiographic parameters between maintained joint space and narrowed joint space groups were compared. RESULTS: The preoperative mean HKA was 1.4° varus and increased to 2.7° varus after THA. This change was related to changes in the NSA, lateral distal femoral angle, and femoral bowing angle. In particular, in the group with a decrease in NSA of > 5°, the preoperative mean HKA was largely changed from 1.4° varus to 4.6° varus after THA. The prostheses with NSA of 132° and 135° also led to greater varus HKA changes than those with an NSA of 138°. Narrowing of the medial knee joint space was related to changes in the varus direction of the HKA, decrease in NSA, increase in femoral offset. CONCLUSION: A large reduction in NSA can lead to considerable varus limb alignment after THA, which can have adverse effects on the medial compartment of the ipsilateral knee.

Effectiveness of locking compression plate for proximal humeral fracture in elderly patients without structural bone grafting: age group of 65-79 compared to 80 and above.

PURPOSE: This study shows the effectiveness of locking compression plate for proximal humeral fractures in elderly patients over 80 years old without structural bone grafting compared age group of 65-79 (Group 1) with 80 and above (Group 2). METHODS: This study included sixty-one patients who underwent using locking compression plate for proximal humeral fractures between April 2016 and November 2021. The patients were divided into two groups. The neck shaft angle (NSA) was checked at immediately after surgery, at 1 month and the final follow-up visit. The NSA changes in the two groups were compared using the independent t-test. In addition, multiple regression analysis was used to find out which factors affect NSA changes. RESULTS: In group 1, the mean difference between NSA immediately after surgery and 1 month after surgery was 2.74°, and group 2 was 2.89°. In group 1, the mean difference in NSA for 1 month after surgery and at the last follow-up was 1.43°, and group 2 was 1.75°. No significant difference was observed in the NSA changes between two groups (p = 0.59, 0.173). Bone marrow density and four-part fracture type were significant difference in NSA changes (p = 0.003, 0.035). The disabilities of the arm, shoulder and hand scale (DASH scale), age, medical support, diabetes and three-part fracture type were no significant in NSA changes. CONCLUSIONS: Using locking compression plate without structural bone grafting is a good option in elderly patients over 80 years old and can help achieve radiological results similar to patients which age group of 67-79.

Computer-assisted analysis of functional internal rotation after reverse total shoulder arthroplasty: implications for component choice and orientation.

PURPOSE: Functional internal rotation (IR) is a combination of extension and IR. It is clinically often limited after reverse total shoulder arthroplasty (RTSA) either due to loss of extension or IR in extension. It was the purpose of this study to determine the ideal in-vitro combination of glenoid and humeral components to achieve impingement-free functional IR. METHODS: RTSA components were virtually implanted into a normal scapula (previously established with a statistical shape model) and into a corresponding humerus using a computer planning program (CASPA). Baseline glenoid configuration consisted of a 28 mm baseplate placed flush with the posteroinferior glenoid rim, a baseplate inclination angle of 96° (relative to the supraspinatus fossa) and a 36 mm standard glenosphere. Baseline humeral configuration consisted of a 12 mm humeral stem, a metaphysis with a neck shaft angle (NSA) of 155° (+ 6 mm medial offset), anatomic torsion of -20° and a symmetric PE inlay (36mmx0mm). Additional configurations with different humeral torsion (-20°, + 10°), NSA (135°, 145°, 155°), baseplate position, diameter, lateralization and inclination were tested. Glenohumeral extension of 5, 10, 20, and 40° was performed first, followed by IR of 20, 40, and 60° with the arm in extension of 40°-the value previously identified as necessary for satisfactory clinical functional IR. The different component combinations were taken through simulated ROM and the impingement volume (mm3) was recorded. Furthermore, the occurrence of impingement was read out in 5° motion increments. RESULTS: In all cases where impingement occurred, it occurred between the PE inlay and the posterior glenoid rim. Only in 11 of 36 combinations full functional IR was possible without impingement. Anterosuperior baseplate positioning showed the highest impingement volume with every combination of NSA and torsion. A posteroinferiorly positioned 26 mm baseplate resulting in an additional 2 mm of inferior overhang as well as 6 mm baseplate lateralization offered the best impingement-free functional IR (5/6 combinations without impingement). Low impingement potential resulted from a combination of NSA 135° and + 10° torsion (4/6 combinations without impingement), followed by NSA 135° and -20° torsion (3/6 combinations without impingement) regardless of glenoid setup. CONCLUSION: The largest impingement-free functional IRs resulted from combining a posteroinferior baseplate position, a greater inferior glenosphere overhang, 90° of baseplate inclination angle, 6 mm glenosphere lateralization with respect to baseline setup, a lower NSA and antetorsion of the humeral component. Surgeons can employ and combine these implant configurations to achieve and improve functional IR when planning and performing RTSA. LEVEL OF EVIDENCE: Basic Science Study, Biomechanics.

The association between reverse total shoulder arthroplasty neck-shaft angle on postoperative patient experienced shoulder disability: a retrospective cohort study.

Background: The neck-shaft angle (NSA) of the glenoid component used in reverse total shoulder arthroplasty (RTSA) was reduced to improve functional outcomes. This led to a decreased abduction but increased external rotation ability of patients who underwent RTSA. The impact of the decreased NSA on patient-reported shoulder disability is unknown but may have important implications for functional ability. Therefore, the aim of this study was to assess the difference in patient experienced shoulder disability between an NSA of 135° and 155° 12 months after RTSA. Methods: In this retrospective cohort study, 109 patients undergoing RTSA were included. In 68 patients, a glenoid component with an NSA of 135° was used and 41 patients received a glenoid component with an NSA of 155°. The primary outcome was Disabilities of the Arm, Shoulder, and Hand (DASH) scores at 12 months and change scores between baseline and 12-month follow-up. Secondary outcomes were complications, Constant Murley Score, Numeric Rating Scale, active forward elevation and external rotation ability. Differences between groups were tested with t-tests or Mann-Whitney U-tests. Results: A mean difference of 10.0 in 12 months postoperative DASH scores between NSA groups was observed in favor of the 135° NSA (P = .004), which did not exceed the Minimal Clinically Important Difference. DASH changes scores did not differ between NSA groups (P = .652). Mean postoperative Constant Murley Score at 12 months was 11.1 higher in the 135° NSA group (P = .013). No differences were observed in complications (P = .721) and postoperative pain (P = .710) between groups. Difference in postoperative external rotation and forward elevation at 12 months was 10° (P = .022) and 20° (P = .046), respectively, in favor of the 135° NSA group, exceeding Minimal Clinically Important Differences. Conclusions: No clinically important difference in patient-reported shoulder disability (DASH) was found between both groups, despite a larger range of motion in the 135° NSA group. This study is the first to show the impact of NSA on patient-reported shoulder disability using the DASH.

Femoral neck-shaft angle can predict the anterior capsular thickness in patients with femoracetabular impingement syndrome.

PURPOSE: To measure the femoral neck-shaft angle (NSA) on computed tomography (CT) images in femoracetabular impingement syndrome (FAIS) patients and explore its relationship with the anterior capsular thickness (ACT). METHODS: A retrospective review of prospectively collected data from 2022 was performed. Inclusion criteria included: primary hip surgery, 18 to 55 years of age, and CT imaging of the hips. Exclusion criteria included: revision hip surgery, mild or borderline hip dysplasia, hip synovitis, and incomplete radiographs and medical records. NSA was measured on CT imaging. ACT was measured using magnetic resonance imaging (MRI). Multiple linear regression was performed to assess the association between ACT and related variables, including age, sex, body mass index (BMI), lateral center-edge angle (LCEA), alpha angle, Beighton test score (BTS), and NSA. RESULTS: A total of 150 patients were included. The mean age, BMI, and NSA were 35.8 ± 11.2 years, 22.8 ± 3.5, and 129.4° ± 7.7°, respectively. Eighty-five (56.7%) patients were females. Multivariable regression analysis revealed that NSA (P = 0.002) and sex (P = 0.001) were significantly negatively correlated with ACT. Age, BMI, LCEA angle, alpha angle, and BTS were not correlated with ACT. CONCLUSIONS: This study confirmed that NSA significantly predicts ACT. A decrease in the NSA by 1° increases the ACT by 0.24 mm. LEVEL OF EVIDENCE: Level III.

Neck shaft angle in reverse shoulder arthroplasty: 135 vs. 145 degrees at minimum 2-year follow-up.

BACKGROUND: The most common complication with reverse shoulder arthroplasty Grammont based design with a 155° neck shaft angle (NSA) is scapular notching. Scapular notching has been associated with reduced clinical outcomes. Reducing the humeral NSA from 155° has been shown to reduce the incidence of scapular notching however it is unknown whether there is a difference in scapular notching between a 145° and 135° NSA. The purpose of this study was to evaluate the effect of decreasing the NSA on scapular notching rate and postoperative range of motion comparing 145° and 135° NSA stems at minimum 2 yr of follow-up. METHODS: Consecutive patients undergoing primary reverse shoulder arthroplasty with a NSA of either 145° or 135° between January 2014 and February 2019 were retrospectively reviewed. Patients were included if they were over the age of 18, had minimum clinical follow-up of 24 mo with true postoperative anteroposterior radiographic view. RESULTS: One hundred and three patients were included for the final analysis: 73 with a 145° NSA and 30 with a 135° NSA stem. The mean age and mean follow-up were respectively 70.9 yr (range, 52.0-89.0) and 32.1 mo. The overall incidence of scapular notching was 46.6 %. There was a statistically significant difference in scapular notching between the 145° (53.4%) and 135° (30%) NSA groups (P = .028). There was no difference in terms of postoperative Constant-Murley Score (mean, 66.1 vs. 68.2; P = .395), Subjective Shoulder Value (mean, 76.5 vs. 83.1%, P = .167), forward flexion (mean, 140° vs. 142°, P = .704), abduction (mean, 123.2° vs. 121.5°, P = .771), external rotation with the arm at the side (mean, 34.1° vs. 37.3°, P = .341) and internal rotation (mean, 5.3 vs. 5.4 pts P = .336) between the 2 groups. CONCLUSION: This is the first study to compare the effect of a 145° vs. 135° NSA on scapular notching rates. The key finding of this study is that scapular notching rate was significantly reduced from 53% to 30% in 135° NSA compared to 145° NSA, after at least 24 mo of follow-up. Our data also show that glenoid lateralization and inferiorization has an influence on scapular notching. We are unable to state that the reduced scapular notching rate was due to a reduction in NSA alone. Despite a lower rate of scapular notching, the 135° NSA group has not shown any significant better clinical and functional outcomes.