Radiocapitellar joint pressures following transradial amputation increase during elbow motion.

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

Global and Spatial Compartmental Interrelationships of Bone Density, Microstructure, Geometry and Biomechanics in the Distal Radius in a Colles' Fracture Study Using HR-pQCT.

Background: Bone parameters derived from HR-pQCT have been investigated on a parameter-by-parameter basis for different clinical conditions. However, little is known regarding the interrelationships of bone parameters and the spatial distribution of these interrelationships. In this work: 1) we investigate compartmental interrelationships of bone parameters; 2) assess the spatial distribution of interrelationships of bone parameters; and 3) compare interrelationships of bone parameters between postmenopausal women with and without a recent Colles' fracture. Methods: Images from the unaffected radius in fracture cases (n=84), and from the non-dominant radius of controls (n=98) were obtained using HR-pQCT. Trabecular voxel-based maps of local bone volume fraction (L.Tb.BV/TV), homogenized volumetric bone mineral density (H.Tb.BMD), homogenized µFEA-derived strain energy density (H.Tb.SED), and homogenized inter-trabecular distances (H.Tb.1/N) were generated; as well as surface-based maps of apparent cortical bone thickness (Surf.app.Ct.Th), porosity-weighted cortical bone thickness (Surf.Ct.SIT), mean cortical BMD (Surf.Ct.BMD), and mean cortical SED (Surf.Ct.SED). Anatomical correspondences across the parametric maps in the study were established via spatial normalization to a common template. Mean values of the parametric maps before spatial normalization were used to assess compartmental Spearman's rank partial correlations of bone parameters (e.g., between H.Tb.BMD and L.Tb.BV/TV or between Surf.Ct.BMD and Surf.app.Ct.Th). Spearman's rank partial correlations were also assessed for each voxel and vertex of the spatially normalized parametric maps, thus generating maps of Spearman's rank partial correlation coefficients. Correlations were performed independently within each group, and compared between groups using the Fisher's Z transformation. Results: All within-group global trabecular and cortical Spearman's rank partial correlations were significant; and the correlations of H.Tb.BMD-L.Tb.BV/TV, H.Tb.BMD-H.Tb.1/N, L.Tb.BV/TV-H.Tb.1/N, Surf.Ct.BMD-Surf.Ct.SED and Surf.Ct.SIT-Surf.Ct.SED were significantly different between controls and fracture cases. The spatial analyses revealed significant heterogeneous voxel- and surface-based correlation coefficient maps across the distal radius for both groups; and the correlation maps of H.Tb.BMD-L.Tb.BV/TV, H.Tb.BMD-H.Tb.1/N, L.Tb.BV/TV-H.Tb.1/N, H.Tb.1/N-H.Tb.SED and Surf.app.Ct.Th - Surf.Ct.SIT yielded small clusters of significant correlation differences between groups. Discussion: The heterogeneous spatial distribution of interrelationships of bone parameters assessing density, microstructure, geometry and biomechanics, along with their global and local differences between controls and fracture cases, may help us further understand different bone mechanisms of bone fracture.

A novel retractor-assisted closed reduction combined with percutaneous pinning fixation for the treatment of elderly distal radius fractures: a retrospective cohort study.

BACKGROUND: Percutaneous pinning fixation (PCP) has been used for the treatment of distal radius fractures for decades, especially in the elderly with fragile soft tissue. However, achieving and maintaining a sound anatomic reduction before PCP is difficult if we use the manipulative reduction method alone. Our study innovatively applied the Steinmann pin retractor for closed reduction combined with PCP, to provide a new protocol for the treatment of distal radius fractures. METHODS: From March 2017 to July 2018, 49 patients out of 57 that met the inclusion criteria but not the exclusion criteria were included in our retrospective cohort study. Sixteen patients were treated with Steinmann pin retractor-assisted closed reduction combined with PCP (S-PCP), and 19 patients were treated with the manipulative reduction combined with PCP (M-PCP), and 14 patients were treated with the manipulative reduction combined with cast splint (M-C). All these patients received a positive postoperative radiological and clinical evaluation. RESULTS: All the patients were followed up for a minimum of 2 years. The radiological parameters in each group improved significantly postoperative (posttreatment). In the S-PCP group, the values of radial height (postoperative, 13.33±1.74 mm; the first follow-up, 13.27±1.81mm; last follow-up, 13.16±1.76mm) and ulnar variance (postoperative, -0.10±1.29mm; the first follow-up, -0.05±1.27mm; last follow-up, -0.12±1.09mm) significantly improved as compared to the M-PCP and M-C groups. While the patients in the M-C group experienced significant re-displacement at the first and last follow-ups, in the S-PCP group, the range of wrist motion including extension (89.94±5.21%), radial deviation (90.69±6.01%), and supination (90.25±5.87%); ulnar deviation (89.81±5.82%) and QuickDASH score (2.70±3.64); and grip strength (92.50±5.59%), pronation (90.50±6.04%), and modified Mayo wrist score (90.94±4.17, the excellent rate reached up to 75%) also improved as compared to the M-PCP group, M-C group, or both groups at the last follow-up. CONCLUSION: S-PCP improves fracture reduction and wrist function and can serve as an effective method for A2(AO/OTA) and A3 type of distal radius fractures in the elderly with limited dorsal comminution, including intra-articular fractures with displacement less than 2mm.

Common Complications of Distal Radial Fractures.

Distal radial fractures are associated with good outcomes; however, although they occur at low rates, complications can significantly impair treatment success. Therefore, the treating surgeon should be aware of potential complications associated with each treatment type and how to best prevent them. Although certain patient-specific and fracture-specific factors may increase the risk of adverse outcomes, most are nonmodifiable risk factors at the time of presentation, so it is imperative that every effort is made to mitigate these risk factors to prevent long-term morbidity. Patients should be well-informed about these complications and potential symptoms so that they can be addressed expeditiously.

Measurement of compensatory wrist joint rotation using three-dimensional motion analysis in patients with unilateral proximal congenital radioulnar synostosis.

OBJECTIVE: This study aims to investigate compensatory rotational movements of the wrist joint in patients with proximal congenital radioulnar synostosis (CRUS), using a valid and reliable three-dimensional (3D) motion analysis technique. METHODS: A total of 26 patients (6 females, 14 males; mean age=15.3 years; and age range=6-32 years) who were diagnosed with unilateral proximal CRUS but were not operated were enrolled in this study. Patients were then categorized into 2 groups: Group I included 5 patients younger than 10 years, and Group II included 15 patients older than 10 years. Eighteen light-reflective skin markers were placed on the bony landmarks of both upper limbs, and both distal forearms were fixed using a U-shaped device to minimize forearm rotation. Each patient grasped the handle of an instrument that used a goniometer to measure wrist rotation; maximal passive pronation and supination angles of the wrist were measured in this manner and also using 3D motion analysis. RESULTS: There was a significant correlation between measurements by the goniometer and 3D motion analysis (r=0.985, p<0.001). The test-retest reliability of the 3D motion analysis was acceptable for both the affected side (ICC=0.992) and the contralateral normal side (ICC=0.997) with low standard measurement errors (1.3° and 0.8°, respectively). Although no significant difference was observed in the range of the wrist rotation between the affected and contralateral sides in Group I (p=0.686), there was a significant difference in the wrist rotation between the affected and contralateral sides in Group II (p=0.001). Further, the pronation angle of the wrist joint was significantly larger in the affected side than that in the contralateral normal side in Group II (p=0.001). CONCLUSION: The 3D motion analysis technique seems to be a valid and reliable method to measure the rotation of the wrist joint. Unilateral proximal CRUS patients older than 10 years of age may develop rotational hypermobility of the wrist joint compared to the contralateral normal side as a compensatory phenomenon. LEVEL OF EVIDENCE: Level III, Diagnostic Study.

Simultaneous ipsilateral distal radius and radial head fractures: Two case reports of radius bipolar fracture.

RATIONALE: Distal radius fracture with simultaneous ipsilateral radial head fracture is a very rare pattern of injury. This type of injury is referred to as 'radius bipolar fracture'. Treatments for this injury pattern can be challenging because both the wrist and elbow need to be considered. There are currently no guidelines for the treatment of this specific type of injury. We report two cases of this unusual pattern of injury treated in our hospital. PATIENT CONCERNS: Case 1 was a 78-year-old female patient and case 2 was a 19-year-old female patient who visited our emergency department with left elbow and wrist pain after slipping and falling. DIAGNOSIS: Plain radiography and computed tomography revealed radius bipolar fracture. Case 1 had an AO type C3 distal radius fracture, a Mason type III radial head fracture. Case 2 had an AO type B2 undisplaced distal radius fracture and a Mason type III radial head fracture. INTERVENTIONS: In case 1, open reduction and internal fixation (ORIF) was performed for the distal radius fracture and radial head replacement arthroplasty for the radial head fracture. In case 2, distal radius fracture was treated conservatively and ORIF was performed for the radial head fracture. OUTCOMES: Bony union as achieved in both cases. At 1-year follow-up, case 1 showed slight limited range of motion of the wrist. Case 2 showed no radius shortening and full range of motion of the wrist and elbow. The Quick disabilities of the arm, shoulder and hand score was 18 and 16, respectively. LESSONS: After this type of injury, the radius length can be changed, and as a result, ulnar variance can be affected. When radial head replaced is considered, it would be better to operate on the wrist first, and then perform radial head replacement. In this way, radiocapitellar overstuffing or instability can be prevented. However, if ORIF is planned for proximal radius fracture, either the proximal or distal radius can be fixed first. Surgeons should try to preserve radial length during treatment to optimize patient outcomes.

Mid- and Long-Term Outcome After Arthroscopically Assisted Transosseous Triangular Fibrocartilage Complex Refixation-Good to Excellent Results in Spite of Some Loss of Stability of the Distal Radioulnar Joint.

PURPOSE: To evaluate mid- and long-term outcomes after arthroscopically-assisted transosseous reattachment of the triangular fibrocartilage complex (TFCC) and to analyze the association of distal radioulnar joint (DRUJ) stability with the clinical outcome. METHODS: Patients treated with an arthroscopically-assisted transosseous reattachment of the deep layer of the TFCC between 2000 and 2009 and a minimum follow-up of 12 months at mid-term and 4 years at long-term follow-up were retrospectively reviewed. Mayo Modified Wrist Score (MMWS); Disabilities of the Arm, Shoulder and Hand (DASH) score; pain visual analogue scale (VAS); grip strength and stability of the DRUJ were assessed at 2 follow-up clinical examinations. At the last follow-up, the Patient-Rated Wrist Evaluation score was additionally recorded. RESULTS: Thirty patients with a mean age of 29 (±13) years were included. Most of the patients were female (70%, n = 21). The mid-term evaluation took place at a median of 30 months (range, 12-83 months). The assessed scores showed statistically significant clinical improvement (MMWS, P < .001; DASH score P < .001; VAS P < .001). Stability assessment showed a stable DRUJ in 23 (76.7%) patients. At a median of 106 months (range 52-215 months), the long-term clinical assessment was performed. The evaluated scores demonstrated persisting significant improvement (MMWS P < .001; DASH score P < .001; VAS P < .001). Stability assessment showed a stable DRUJ in 19 patients (63.3%). DRUJ instability did not correlate with clinical outcome. No permanent surgery-related complications occurred. CONCLUSION: Arthroscopically-assisted transosseous reattachment of the deep fibers of radioulnar ligaments leads to excellent and good clinical results in mid- and long-term follow-up. In 95.5% of the analyzed patients, the measured improvement in the DASH score exceeded the in literature reported minimal clinically important difference of 13.5. Loss of DRUJ stability during follow-up was not associated with deterioration of clinical parameters and patient satisfaction. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Consequences of Hyperthyroidism and Its Treatment for Bone Microarchitecture Assessed by High-Resolution Peripheral Quantitative Computed Tomography.

Background: Hyperthyroidism is associated with bone mass reduction and increased fracture risk, but the effects on other important bone parameters have been sparsely examined. Therefore, we investigated bone microarchitecture and estimated bone strength by high-resolution peripheral quantitative computed tomography (HR-pQCT) in hyperthyroid patients at diagnosis and after being euthyroid for at least one year. Methods: Two approaches were used: (A) a case-control study comparing 61 hyperthyroid women with 61 euthyroid women matched for age and menopause status; (B) a follow-up study, in which 46 of the 61 women were re-examined after having been euthyroid for one year. HR-pQCT of the distal radius and tibia, and dual-energy X-ray absorptiometry (DXA) of the lumbar spine and the hip were performed. Results: In analysis A: In the radius, compared with the healthy controls, hyperthyroid patients had higher total area (16.9% ± 29.5%; p < 0.001), trabecular area (28.6% ± 45.7%; p < 0.001), and lower cortical area (-11.7% ± 23.2%; p < 0.001). Total volumetric bone mineral density (vBMD) (-13.9% ± 26.5%; p < 0.001), cortical vBMD (-5.8% ± 7.9%; p < 0.001), cortical thickness (-16.7% ± 26.0%; p < 0.001), and estimated bone strength (-6.6% ± 19.5%; p < 0.01) were lower. No significant differences were found in the tibia or in the DXA parameters. In analysis B: In the radius, significant improvements were observed in the cortical area (2.1% ± 4.6%; p < 0.01), cortical thickness (2.5% ± 5.1%; p < 0.001), and total vBMD (0.8% ± 3.0%; p < 0.05). Trabecular area decreased (-0.5% ± 1.0%; p < 0.01) and trabecular separation increased (2.0% ± 8.3%; p < 0.05). In the tibia, cortical area (3.6% ± 7.3%; p < 0.01) and cortical thickness (3.8% ± 7.6%; p < 0.01) increased, and trabecular area decreased (-0.5% ± 1.1%; p < 0.01). Areal BMD, measured by DXA, increased in the spine (1.1% ± 3.4%; p < 0.05) and in the hip (2.0% ± 3.8%; p < 0.01). Conclusions: Compared with the healthy control group, hyperthyroid women had lower vBMD, lower estimated bone strength, and compromised cortical microarchitecture in the radius. After restoration of euthyroidism, significant improvements in vBMD and cortical microarchitecture were observed, highlighting the importance of achieving and maintaining euthyroidism.

Musculoskeletal abnormalities in a large international cohort of boys with 49,XXXXY.

49,XXXXY is the rarest X and Y chromosomal variation, with an incidence of 1 in 80,000-100,000 live male births and has been associated with numerous musculoskeletal abnormalities. Data was collected from an international cohort of boys with 49,XXXXY over 10 years. Children were evaluated by a multidisciplinary team consisting of a pediatric orthopedist, a neurogeneticist, a neurodevelopmentalist, and two physical therapists. Increased rates of torticollis (32.4%), hamstring tightness (42%), radioulnar synostosis (67.6%), pes planus (65.2%), and other foot abnormalities (86.9%) were observed. Several anomalies increased with age, specifically hamstring tightness, kyphosis, and scoliosis. The elucidation of the orthopedic profile of this population is necessary in order to provide healthcare providers with current medical information. This research further supports the necessity for the comprehensive multidisciplinary treatment of boys with 49,XXXXY.

Association between forearm cortical bone properties and handgrip strength in women with distal radius fractures: A cross-sectional study.

OBJECTIVES: Mechanical and biochemical bone properties are influenced by muscles. However, the muscle-bone interaction has not been fully elucidated regarding the upper extremities. The objective of the present study was to evaluate the mechanical muscle-bone interaction at the forearm by evaluating the relationship between the properties of three-dimensional (3D) forearm cortical bone models derived from conventional computed tomography (CT) images and handgrip strength (HGS). METHODS: A total of 108 women (mean age, 75.2 ± 9.4 years; range, 62-101 years) with a distal radius fracture who took conventional CT scans for the assessment of the fracture were included in this study. Distal radius 3D models were reconstructed and the average cortical bone density (Cd) and thickness (Ct) of the region of interest (ROI), which might be affected by the forearm flexor muscles, were calculated using a 3D modeling software. Clinical parameters including HGS, lumbar and hip bone mineral densities (BMDs), and other demographic factors were also obtained. A multivariate linear regression analysis was performed to identify relevant factors associated with HGS. RESULTS: HGS was found to be independently associated with height and Cd, but no significant difference was found between HGS and Ct, age, weight, as well as lumber and hip BMDs. CONCLUSIONS: Cortical bone density might be associated with HGS, which is generated by the forearm flexor muscles. Hence, the mechanical muscle-bone interaction in the upper extremities could be supported by the present study.

Radial neck fracture in children: anatomic and functional results of Metaizeau technique.

Fractures of the radial neck accounts for 1% of all childhood fractures and 5% to 10% of childhood traumatic lesions involving the elbow. Intramedullary percutaneous nail reduction (Metaizeau technique) is considered the most effective surgical technique. The purpose of this study was to identify the main clinical features of radial neck fracture in children and to evaluate the anatomical and functional results of the Metaizeau technique. In this retrospective study, we evaluated 22 patients under the age of 16 who were treated for radial neck fracture at the orthopedic and trauma surgery department of Sahloul University Hospital in Sousse over a period of 16 years from January 2001 to April 2017. Authors used Metaizeau classification. Functional results were evaluated by Mayo elbow performance score (MEPS) and the radiological evaluation was based on standard images with measurement of the residual rocker. The average age was 8.6 years (5-13 years). Seven fracture were grade III injuries and three grade IV. In the immediate postoperative period, radiological measurements showed a residual rocker less than 20° in 86.3% and more than 20° in 13.7% of cases. At an average follow-up of 13 months and a half, the MEPS score was excellent and good for 17 patients. Four types of complications were found: necrosis of the radial head in 1 case, pseudarthrosis in 1 case, periarticular calcification in 2 cases and stiff-ness of the elbow in 3 cases. Despite the small number of patients in our series, we believe that the elastic stable intramedullary pinning according to the Metaizeau technique is the treatment of choice for displaced radial neck fractures in children.

Distal radius sections offer accurate and precise estimates of forearm fracture load.

BACKGROUND: Forearm fracture risk can be estimated via factor-of-risk: the ratio of applied impact force to forearm fracture load. Simple techniques are available for estimating impact force associated with a fall; estimating forearm fracture load is more challenging. Our aim was to assess whether failure load estimates of sections of the distal radius (acquired using High-Resolution peripheral Quantitative Computed Tomography and finite element modeling) offer accurate and precise estimates of forearm fracture load. METHODS: We scanned a section of the distal radius of 19 cadaveric forearms (female, mean age 83.7, SD 8.3), and 34 women (75.0, 7.7). Sections were converted to finite element models and failure loads were acquired for different failure criteria. We assessed forearm fracture load using experimental testing simulating a fall on the outstretched hand. We used linear regression to derive relationships between ex vivo forearm fracture load and finite element derived distal radius failure load. We used derived regression coefficients to estimate forearm fracture load, and assessed explained variance and prediction error. We used root-mean-squared coefficients of variation to assess in vivo precision errors of estimated forearm fracture load. FINDINGS: Failure load estimates of sections of the distal radius, used in conjunction with derived regression coefficients, explained 89-90% of the variance in experimentally-measured forearm fracture load with prediction errors <6.8% and precision errors <5.0%. INTERPRETATION: Failure load estimates of distal radius sections can reliably estimate forearm fracture load experienced during a fall. Forearm fracture load estimates can be used to improve factor-of-risk predictions for forearm fracture.

Growth Disturbance Following Intra-articular Distal Radius Fractures in the Skeletally Immature Patient.

INTRODUCTION: The purpose of this study was to characterize the incidence of growth disturbance following intra-articular distal radius fractures in skeletally immature patients and to assess early radiographic and functional outcomes. METHODS: A retrospective investigation of pediatric patients with intra-articular distal radius fractures between 1997 and 2012 at a single institution was performed. Pathologic fractures and fractures in patients with closed physes were excluded. In total, 28 patients (24 males, 4 females), with a mean age of 13.8 years and mean follow-up of 31.7 months, met inclusion criteria. Fractures were categorized according to the Salter-Harris classification, and all radiographs were assessed for evidence of physeal disturbance. Information regarding treatment and early clinical results were obtained from a medical record review. Functional outcomes using the Disabilities of the Arm, Shoulder, and Hand (DASH) and Modified Mayo Wrist Score (MMWS) were collected. Fisher exact test was used to compare the incidence of physeal arrest in the study population to previously published rates of physeal arrest in extra-articular fractures involving the distal radius. Because the data were not parametrically distributed, the Mann-Whitney-Wilcoxon test was used to compare those who did and did not develop physeal arrest. RESULTS: Of the 28 patients, 9 (32%) sustained Salter-Harris III fractures and 19 (68%) sustained Salter-Harris IV fractures. Growth disturbance occurred in 12 (43%) patients, comprised of 3 Salter-Harris III fractures and 9 Salter-Harris IV fractures; 7 of these patients underwent surgical intervention to address deformity. All 4 children age 10 years or younger had growth arrests that underwent subsequent procedures for a skeletal rebalancing of the wrist. No significant differences in DASH or MMWS were seen in the short term between patients who did or did not have physeal arrest. CONCLUSIONS: Intra-articular distal radius fractures in skeletally immature patients have a considerably higher rate of physeal growth arrest than extra-articular physeal fractures. Following acute management aimed at restoring and preserving anatomic physeal and articular alignment, follow-up radiographs should be obtained to evaluate for physeal arrest in skeletally immature children. Patients and families should be counseled regarding the high rate of growth disturbance and the potential need for deformity correction in the future, particularly in younger children. LEVEL OF EVIDENCE: IV-case series.

Determinants of Bone Material Strength and Cortical Porosity in Patients with Type 2 Diabetes Mellitus.

CONTEXT: Reduced bone material strength index (BMSi) and increased cortical porosity (CtPo) have emerged as potentially contributing to fracture risk in type 2 diabetes mellitus (T2DM) patients. OBJECTIVE: To determine whether BMSi or CtPo are related to other diabetic complications. DESIGN: Cross-sectional observational study. SETTING: Subjects recruited from a random sample of southeast Minnesota residents. PARTICIPANTS: A total of 171 T2DM patients (mean age, 68.8 years) and 108 age-matched nondiabetic controls (mean age, 67.3 years). MAIN MEASURES: Bone material strength index was measured using microindentation, skin advanced glycation end-products (AGEs) measured using autofluorescence, high-resolution peripheral quantitative computed tomography at the distal radius and tibia, assessment of diabetic microvascular complications including urine microalbuminuria, retinopathy, neuropathy, and vascular disease (ankle brachial index and transcutaneous oxygen tension [TcPO2]). All analyses were adjusted for age, sex, and body mass index. RESULTS: Skin AGEs were negatively correlated with the BMSi in both T2DM (r = -0.30, P < 0.001) and control (r = -0.23, P = 0.020) subjects. In relating diabetic complications to CtPo, we found that T2DM patients with clinically significant peripheral vascular disease (TcPO2 ≤ 40 mm Hg) had higher (+21.0%, P = 0.031) CtPo at the distal tibia as compared to controls; in these subjects, CtPo was negatively correlated with TcPO2 at both the distal tibia (r = -0.39, P = 0.041) and radius (r = -0.41, P = 0.029). CONCLUSIONS: Our findings demonstrate that bone material properties are related to AGE accumulation regardless of diabetes status, while CtPo in T2DM patients is linked to TcPO2, a measure of microvascular blood flow.

Lunate loads following different osteotomies used to treat Kienböck's disease: A 3D finite element analysis.

BACKGROUND: One of most accepted principles for treating Kienböck's disease before wrist degeneration settles in is to decompress the lunate by an osteotomy. Several osteotomies have been proposed since 1935. However, they are based on biomechanical hypotheses that are sometimes conflicting: This study compares the decompression effect of radius transverse shortening, radius lateral closing and medial closing wedge osteotomies, capitate shortening - with and without hamate shortening - and a Camembert-type radius wedge osteotomy with and without ulnar head shortening according to Sennwald. METHODS: We built a 3D wrist model using finite elements that included the metacarpal, carpal and forearm bones. All wrist ligaments and Triangular Fibrocartilage Complex were incorporated in the simulation. Load was applied on the metacarpals with the forearm bones fixed. We then applied the different osteotomies to the model. FINDINGS: When load was applied to the wrist, the osteotomies that best unloaded the lunate were the capitate shortening osteotomy combined with hamate shortening and the Camembert osteotomy combined with ulna shortening; the latter was the only osteotomy that completely unloaded the lunate. INTERPRETATION: We think the association of the radius Camembert osteotomy and ulna Sennwald's shortening osteotomy is the most effective procedure to propose in Kienböck's disease.

Biomechanical analysis of simultaneous distal and proximal radio-ulnar joint instability.

BACKGROUND: Simultaneous dislocation of the proximal and distal radio-ulnar joints without bony injuries has been reported, but the mechanism remains unclear. We investigated concurrent proximal and distal radio-ulnar joint instability after sequential sectioning of the annular ligament, triangular fibrocartilage complex, and quadrate ligament. METHODS: We performed this biomechanical study with six fresh-frozen cadaveric upper extremities. Proximal and distal radio-ulnar joint displacement was measured using an electromagnetic tracking device during passive mobility testing with anterior, lateral, and posterior loads on the radial head with pronation, supination, and neutral rotation. Measurements were statistically analyzed using the generalized linear mixed model. FINDINGS: Proximal radio-ulnar joint instability was significantly greater after sectioning of the annular (lateral: 1.4%, P < .05; posterior: 0.7%, P < .05) and quadrate (lateral: 43.7%, P < .05; posterior: 29.5%, P < .05) ligament. Distal radio-ulnar joint instability was significantly greater in every sequential stage (final stage: anterior: 24.1%, P < .05; lateral 21.0%, P < .05; posterior: 31.3%, P < .05). Finally, significant simultaneous instability of the joints was observed after sectioning of the annular ligament, triangular fibrocartilage complex, and quadrate ligament, and neutral rotation potentially induced gross instability. INTERPRETATION: Our ligament injury model induced simultaneous proximal and distal radio-ulnar joint instability without bony or interosseous membrane injury, probably induced by severe soft tissue injury. Proximal radio-ulnar joint instability may influence distal radio-ulnar joint instability from pivoting of the interosseous membrane. Our findings will help surgeons evaluate the magnitude of soft tissue injury and plan surgery for patients with simultaneous proximal and distal radio-ulnar joint instability.

Association between bone mineral density and ulnar styloid fracture in older Japanese adults with low-energy distal radius fracture.

We investigated the association of the ulnar styloid fracture (USF) with the bone mineral status and fractured radial displacement in elderly patients. The presence of USF correlates with decreased BMD and severe displacement of the radius. These findings are helpful in treating osteoporosis to prevent subsequent fragility fracture. PURPOSE: The pathogenesis of ulnar styloid fracture (USF), which often occurs with distal radius fracture (DRF), is unclear. This study aimed to investigate whether USF concomitant with low-energy DRF was associated with the bone mineral status and the degree of radiographically observed pretreatment radius displacement in Japanese adults above 50 years of age. METHODS: The study subjects were 45 (44 female, 1 male) consecutive patients aged > 50 years with DRF caused by falls from June 2015 to May 2016. Fractures due to high-energy injuries were excluded. Patients were divided into two groups according to the presence or absence of USF. Radius displacement was assessed on anteroposterior and lateral radiographs by measuring ulnar variance, radial inclination, and volar tilt at initial examination before manual reduction of the bone. Bone mineral density (BMD) of the lumbar spine, femoral neck, and distal radius was also measured by dual-energy X-ray absorptiometry within 1 week of injury. RESULTS: Significant differences in the BMD values of femoral neck, ulnar variance, radial inclination, and volar tilt were found between patients with USF and those without USF (all comparisons, p < 0.05). Logistic regression analysis of all subject data identified that volar tilt was significantly associated with the presence of USF (p = 0.048). CONCLUSIONS: The presence of USF in low-energy DRF correlates with the decreased BMD of femoral neck and severe displacement of radius in elderly patients. These findings are helpful for the treatment of osteoporosis to prevent subsequent fragility fracture.

Effect of ulnar angulation and soft tissue sectioning on radial head stability in anterior Monteggia injuries: an in vitro biomechanical study.

BACKGROUND: Radial head instability continues to be a challenge in the management of anterior Monteggia injuries; however, there is a paucity of literature on the factors that contribute to this instability. The aim of this biomechanical investigation was to examine the effects of ulnar angulation and soft tissue insufficiency on radial head stability in anterior Monteggia injuries. METHODS: Six cadaveric arms were mounted in an elbow motion simulator. Radial head translation was measured during simulated active elbow flexion with the forearm supinated. After testing the elbows in the intact state, the ulna was osteotomized and tested at 0°, 10°, 20°, and 30° of extension angulation. To examine the effect of soft tissue insufficiency, the anterior radiocapitellar joint capsule, annular ligament, quadrate ligament, and the proximal and middle interosseous membrane (IOM) were sequentially sectioned. RESULTS: There was a significant increase in anterior radial head translation with greater ulnar extension angulation. Sequential soft tissue sectioning also significantly increased anterior radial head translation. There was no increase in radial head translation with isolated sectioning of the anterior radiocapitellar joint capsule. Additional sectioning of the annular ligament and quadrate ligament slightly increased anterior radial head translation but did not reach statistical significance. Subsequent sectioning of the proximal and middle IOM resulted in significant increases in anterior radial head translation. CONCLUSION: Our study demonstrates that progressive ulnar extension angulation results in an incremental increase in anterior radial head translation in anterior Monteggia injuries. Moreover, increasing magnitudes of soft tissue disruption result in greater anterior radial head instability.

Correlation between radiographic findings and clinical failure in monopolar radial head replacement.

INTRODUCTION: The purpose of this study is to analyze the mid-term outcomes of a modular monopolar type of radial head arthroplasty in the treatment of complex fractures associated with acute elbow joint instability. We postulated that radiographic changes are related to the development of clinical complications. MATERIALS AND METHODS: We evaluated at last follow-up 26 radial head arthroplasties in 26 consecutive patients who were followed for at least one and a half year. All patients had suffered radial head fractures (Mason III) in the context of unstable elbow injuries. Definitive treatment of the radial fracture was performed with modular and monopolar prosthesis which was inserted as a press fit. All patients were evaluated preoperatively and postoperatively. The evaluation included a clinical examination and a protocolized imaging study (standard X-Rays and CT) of the elbow. We analyzed the incidence of: heterotopic ossifications, secondary radiocapitellar joint osteoarthritis, hardware loosening, hardware disengagement, and joint infection. Diagnosis of clinical failure of the implant was defined as the time to the second surgery due to major complications related to the prosthesis, such as persistent lateral side pain or elbow stiffness and any kind of implant instability or dislocation. RESULTS: The implant-specific reoperation rate was 15% (four reoperations). The need for the second surgery was statistically associated with heterotopic ossifications, radiocapitellar osteoarthritis and cortical resorption around radial neck (p = 0.054, p = 0.033, and p = 0.019, respectively), being periprosthetic osteolysis the most likely factor related to failure, and radial pain the main symptom leading to surgical revision. CONCLUSIONS: Our study shows a positive association between radiographic findings and patient symptoms for postoperative complications after radial head arthroplasty. Failed radial head replacements may lead to reoperation mainly due to pain, and this can be distinguished from other causes of pain in elbow region based on its radial location. Radiological loosening was prevalent in this group of failed replacement.

Bone Health Following Bariatric Surgery: An Update.

Obesity rates are increasing rapidly, and bariatric surgery is currently the most effective tool for weight loss. Recently, bariatric surgery induced bone loss has gained attention. Such detrimental effect on bone is multifactorial and causes may include nutrient deficiencies, gut and gonadal hormonal changes, mechanical unloading, loss of lean mass, increased bone marrow fat, and increased risk of fall. This review describes the available evidence on bone loss and fracture risk following bariatric surgery and summarizes the guidelines on the topic. Increased bone resorption starts early postsurgery, and bone markers peak at 1-2 yr. Across studies, the drop in areal bone mineral density is inconsistent at the lumbar spine, while a 2%-5% drop at 6 mo and a 6%-10.5% at 9-12 mo are observed at the total hip. Conversely, studies using quantitative CT showed a 6%-7% decrease in volumetric bone mineral density at the lumbar spine at 6-12 mo postsurgery. These studies also report significant bone loss at the radius and tibia, in addition to alteration in bone microarchitecture. Fracture risk increases 2 yr after surgery, more so following malabsorptive procedures. Fractures were reported at axial, weight bearing sites and at appendicular sites. The available evidence is very heterogeneous, and mostly derived from studies on Roux-en-y gastric bypass in premenopausal women. Data on restrictive procedures is scarce. Our findings suggest that the early postoperative phase represents the "golden window" to intervene and promote bone health. More research is needed to determine the effect of different bariatric procedures on bone, to identify optimal interventions to prevent bone loss and to characterize high risk individuals who should be targeted.