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.

Relationship between ultrasonographic hand muscle thickness measurements and muscle strength following median or ulnar nerve reconstruction.

INTRODUCTION: The aim of this study was to assess the relationship between ultrasonographic hand muscle thickness measurements and hand muscle strength in patients who underwent median or ulnar nerve reconstruction. METHODS: In this prospective, cross-sectional study, intrinsic hand muscle thicknesses were measured using ultrasound with a 4- to 13-MHz linear-array probe. Measurements of hand strength were performed using a dynamometer and a pinchmeter. RESULTS: In the median nerve group (n = 11), a moderate correlation (r = 0.694; P = .018) was observed between lateral pinch strength and transverse thenar thickness. In the ulnar nerve group (n = 11), longitudinal thenar thickness below the flexor pollicis longus tendon was moderate to highly correlated with pinch and handgrip strengths (r = 0.726-0.893; P < .05); whole transverse thenar thickness was moderate to highly correlated with pinch strengths (r = 0.724-0.836; P < .05). DISCUSSION: Sonographic measurements of intrinsic hand muscle thickness may be a useful tool for the assessment and follow-up of patients with median or ulnar nerve injury.

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.

A Biomechanical Comparison of Fiberglass Casts and 3-Dimensional-Printed, Open-Latticed, Ventilated Casts.

Background: The aim of this study was to quantify the stabilizing properties of a 3-dimensional (3D)-printed short-arm cast and compare those properties with traditional fiberglass casts in a cadaveric subacute distal radius fracture model. Methods: A cadaveric subacute fracture model was created in 8 pairs of forearms. The specimens were equally allocated to a fiberglass cast or 3D-printed cast group. All specimens were subjected to 3 biomechanical testing modalities simulating daily life use: flexion and extension of digits, pronation and supination of the hand, and 3-point bending. Between each loading modality, radiological evaluation of the specimens was performed to evaluate possible interval displacement. Interfragmentary motion was quantified using a 3D motion-tracking system. Results: Radiographic assessment did not reveal statistically significant differences in radiographic parameters between the 2 groups before and after biomechanical testing. A statistically significant difference in interfragmentary motion was calculated with the 3-point bending test, with a mean difference of 0.44 (±0.48) mm of motion. Conclusions: A statistically significant difference in interfragmentary motion between the 2 casting groups was only identified in 3-point bending. However, the clinical relevance of this motion remains unclear as the absolute motion is less than 1 mm. The results of this study show noninferiority of the 3D-printed casts compared with the traditional fiberglass casts in immobilizing a subacute distal radius fracture model. These results support the execution of a prospective randomized clinical trial comparing both casting techniques.

Bypass surgery in a mangled forearm using an intramedullary tunnel through the radius.

Critical ischemia in the upper extremity is rare. A surgical bypass is thought to be the superior treatment option. We describe a rare case where regular tunneling options of the bypass were not available and an intramedullary tunnel was used.

Effect of soft tissue injury and ulnar angulation on radial head instability in a Bado type I Monteggia fracture model.

The effects of soft tissue damage and ulnar angulation deformity on radial head instability in Monteggia fractures are unclear. We tested the hypothesis that radial head instability correlates with the magnitude of ulnar angular deformity and the degree of proximal forearm soft tissue injury in Bado type I Monteggia fractures.We performed a biomechanical study in 6 fresh-frozen cadaveric upper extremities. Monteggia fractures were simulated by anterior ulnar angulation osteotomy and sequential sectioning of ligamentous structures. We measured radial head displacement during passive mobility testing in pronation, supination, and neutral rotation using an electromagnetic tracking device. Measurements at various ligament sectioning stages and ulnar angulation substages were statistically compared with those in the intact elbow.Radial head displacement increased with sequential ligament sectioning and increased proportionally with the degree of anterior ulnar angulation. Annular ligament sectioning resulted in a significant increase in displacement only in pronation (P < .05). When the anterior ulnar deformity was reproduced, the radial head displaced least in supination. The addition of proximal interosseous membrane sectioning significantly increased the radial head displacement in supination (P < .05), regardless of the degree of anterior ulnar angulation.Our Monteggia fracture model showed that radial head instability is influenced by the degree of soft tissue damage and ulnar angulation. Annular ligament injury combined with a minimal (5°) ulnar deformity may cause elbow instability, especially in pronation. The proximal interosseous membrane contributes to radial head stability in supination, regardless of ulnar angulation, and proximal interosseous membrane injury led to significant radial head instability in supination.

Immediate improvements of supination range of motion and strength following pronator teres muscle friction massage: a clinical trial comparing people with and without supination limited motion.

OBJECTIVES: To investigate the effects of friction massage techniques on the pronator teres muscle on supination range of motion (ROM) and supinator strength in individuals with and without limited supination ROM. METHODS: In total, 26 subjects (13 with limited supination ROM and 13 healthy subjects) volunteered to participate in this study. We used a customized wrist cuff. Supination ROM and supinator strength were measured with a 9-axis inertial motion sensor and load cell. The friction massage protocol was executed with the pronator teres muscle in a relaxed position. Then supination ROM and supinator strength were measured again. RESULTS: There was no significant interaction effect on supination ROM, which was significantly greater in the limited supination and control groups. A post hoc t-test revealed that the limited supination group achieved a significantly increased post-test supination ROM (51.7 ± 7.8°) compared to the pre-test value (43.6 ± 5.2°). In addition, the control group achieved a significant increase in post-test supination ROM (67.7 ± 10.0°) compared to the pre-test value (61.4 ± 7.7°). There was no significant interaction effect on supinator strength. Supinator strength was significantly greater in the limited supination and control groups. A post hoc t-test revealed a significant difference in supinator strength between the pre- and post-test values in the limited supination group. DISCUSSION: Friction massage helps restore a limited ROM of the forearm supination motion and immediately increases supinator muscle strength. This technique can be used as an intervention method to improve muscle strength in patients with limited supination ROM.

Union Rates and Reported Range of Motion Are Acceptable After Open Forearm Fractures in Military Combatants.

BACKGROUND: High-energy open forearm fractures are unique injuries frequently complicated by neurovascular and soft tissue injuries. Few studies have evaluated the factors associated with nonunion and loss of motion after these injuries, particularly in the setting of blast injuries. QUESTIONS/PURPOSES: (1) In military service members with high-energy open forearm fractures, what proportion achieved primary or secondary union? (2) What is the pronation-supination arc of motion as stratified by the presence or absence of heterotopic ossification (HO) and synostosis? (3) What are the risks of heterotopic ossification and synostosis? (4) What factors may be associated with forearm fracture nonunion? METHODS: A retrospective study of all open forearm fractures treated at a tertiary military referral center from January 2004 to December 2014 was performed. In all, 76 patients were identified and three were excluded, leaving 73 patients for inclusion. All 73 patients had serial radiographs to assess for HO and union. Only 64 patients had rotational range of motion (ROM) data. All patients returned to the operating room at least once after initial irrigation and débridement to ensure the soft tissue envelope was stable before definitive fixation. The indication for repeat irrigation and débridement was determined by clinical appearance. Patient demographics, fracture and soft tissue injury patterns, surgical treatments, neurovascular status at the time of injury, incidence of infection, heterotopic ossification (defined as the presence of heterotopic bone visible on serial radiographs), radioulnar synostosis, bony status after initial definitive treatment (union, nonunion, or amputation), and forearm rotation at final followup were retrospectively obtained from chart review by someone other than the operating surgeon. Seventy-six open forearm fractures in 76 patients were reviewed; 73 patients were examined for osseous union as three went on to early amputation, and 64 patients had forearm ROM data available for analysis. Union was determined by earliest radiology or orthopaedic staff official dictation stating the fracture was healed. Nonunion was defined as the clinical determination by the orthopaedist for a repeat procedure to achieve bony union. Secondary union was defined as union after reoperation to achieve bony union, and final union was defined as overall percentage of patients who were healed at final followup. Of the patients analyzed for union, 20 had less than 1 year of followup, and of these, none had nonunion. Of the patients analyzed for ROM, eight patients had less than 6 months of followup (range, 84-176 days). Of these, one patient had decreased ROM, none had a synostosis, and the remaining had > 140° of motion. RESULTS: Initial treatment resulted in primary union in 62 of 73 patients (85%); secondary union was achieved in eight of 11 patients (73%); and final union was achieved in 70 of 73 patients (96%). Although pronation-supination arc in patients without HO was 140° ± 35°, a limited pronation-supination arc was primarily associated with synostosis (arc: 40° ± 40°; mean difference from patients without HO: 103° [95% confidence interval {CI}, 77°-129°], p < 0.001); patients with HO but without synostosis had fewer limitations to ROM than those with synostosis (arc: 110° ± 80°, mean difference: 77° [35°-119°], p < 0.001). Heterotopic ossification developed in 40 of 73 patients (55%), including a radioulnar synostosis in 14 patients (19%). Bone loss at the fracture site (relative risk (RR) 6.2; 95% CI, 1.8-21) and healing complicated by infection (RR, 9.9; 95% CI, 4.9-20) were associated with the development of nonunion after initial treatment. Other potential factors such as smoking status, vascular injury, both-bone involvement, need for free flap coverage and blast mechanism were not associated. CONCLUSIONS: Despite a high-energy mechanism of injury and high rate of soft tissue defects, the ultimate probability of fracture union in our series was high with a low infection risk. Nonunions were associated with bone loss and deep infection. Functional motion was achieved in most patients despite increased burden of HO and synostosis compared with civilian populations. However, if synostosis did not develop, HO itself did not appear to interfere with functional ROM. Future investigations may provide improved decision-making tools for timing of fixation and prophylactic means against HO synostosis. LEVEL OF EVIDENCE: Level III, therapeutic study.

Recovery of Bone Mineral Mass After Upper Limb Fractures in Children and Teenagers.

BACKGROUND: Loss of bone mineral mass and muscle atrophy are predictable consequences of cast-mediated immobilization following wrist and forearm fractures. This study aimed to prospectively determine whether previously reported lower bone mineral mass following immobilization for wrist and forearm fractures in children and teenagers had recovered at 6- and 18-month follow-up. METHODS: We recruited 50 children and teenagers who underwent a cast-mediated immobilization for a forearm or wrist fracture. Dual-energy x-ray absorptiometry scans of different skeletal sites were performed at the time of fracture, at cast removal, at 6 and at 18-month follow-up. Injured patients were paired with healthy controls according to sex and age. Dual-energy x-ray absorptiometry values were compared between groups and the injured and uninjured forearms of the patients. RESULTS: At the time of fracture, injured and healthy subjects showed no differences between their bone mineral density (BMD) and bone mineral content (BMC) z-scores at the lumbar spine, or between their BMDs at the peripheral wrist. At cast removal, upper limb bone mineral variables were significantly lower in the injured group (except for the ultradistal radius) than in the uninjured group, with differences ranging from 3.8% to 10.2%. No residual decrease in bone mineral variables was observed at any upper limb site at 6- and 18-month follow-up (28 injured patients). Significant residual increases in the BMDs and BMCs were observed for the injured group's ultradistal radius and whole wrists (+4.8% to +5.2%). CONCLUSIONS: A rapid bone mass reversal occurs by resumption of mobilization, with full bone recovery 6 months after a forearm or wrist fracture. Finally, healing bone callus could introduce a bias into the interpretation of BMD and BMC data at the fracture site, not only at cast removal but also 18 months after the fracture.

Free vascularized osteoseptocutaneous fibular flap for radius shaft nonunion: The final solution when the iliac crest autograft fails. A case report.

Treatment of forearm nonunion associated with bone defects can be challenging. Restoring the correct length and rotation are two main principles for the management of these patients. Herein, we describe a patient with isolated radius nonunion already treated with an iliac crest autograft with no success. A free vascularized osteoseptocutaneous fibular autogenous graft was harvested as the final solution to managed long bone defect after previous multiple surgeries. At the 1- year follow-up, the patient gained full range of motion and was functioning well.

Rates of neurovascular injury, compartment syndrome, and early infection in operatively treated civilian ballistic forearm fractures.

PURPOSE: The purpose of this study is to evaluate the incidence of neurovascular injuries, compartment syndrome, early postoperative infection as well as the injury factors predictive of neurovascular injury following ballistic fractures of the radius and ulna. METHODS: A retrospective review was performed to identify all ballistic fractures of the radius and ulna in skeletally mature patients over a 5-year period at a single level-1 trauma center. Chart and radiographic review was performed to identify patient and injury demographics, associated neurologic or vascular injuries, and fracture characteristics. Fracture location was measured on computerized imaging software and fractures were grouped into bone(s) segments involved. Proximal, mid-diaphyseal, and distal locations were used for statistical analysis. RESULTS: Fifty-six extremities in fifty-five patients were identified (mean age 32 years; male to female ratio 9:1). Overall incidence of neurologic injury was 50%, arterial injury 32%, and compartment syndrome 7.1%. Presence of a proximal third forearm fracture was associated with an increased risk for neurologic injury (p < 0.01), with an odds ratio of 5.7 (95% confidence interval, 1.7-18.4). Furthermore, all high velocity/energy ballistic injuries had associated neurologic injuries (p = 0.02). CONCLUSION: Ballistic forearm fractures result in high rates of neurovascular injury. Fractures caused by high velocity/energy firearms have extremely high rates of neurologic injury when compared with low velocity ballistic injuries. Ballistic fractures involving the proximal third of the radius or ulna are five times more likely to be associated with neurologic injury after a ballistic injury and should be assessed carefully on initial evaluation.

Intramedullary nailing of forearm shaft fractures by biodegradable compared with titanium nails: Results of a prospective randomized trial in children with at least two years of follow-up.

There are disadvantages in Elastic Stable Intramedullary Nailing (ESIN) of forearm-shaft fractures, such as the need of implant removal. Biodegradable Intramedullary Nailing (BIN) is a new technique developed for these fractures. We hypothesized that there is no difference in rotational ROM between the patients treated by BIN vs. ESIN. A randomized, controlled clinical trial included patients, aged 5-15 years, requiring surgery for forearm-shaft fractures. Biodegradable polylactide-co-glycolide (PLGA) nails (Activa IM-Nail™, Bioretec Ltd., Finland) were used in 19 and titanium nails (TEN®, SynthesDePuy Ltd., USA) in 16 patients. Rotational ROM of forearm after two years was the primary outcome. Elbow and wrist ROM, pain and radiographic bone healing were secondary outcomes. Forearm rotation was mean 162° and 151° in BIN and ESIN groups, respectively (P = 0.201). No difference between the groups was found in any other ROMs. Three cases in the ESIN vs. none in the BIN group reported pain (P = 0.113). There was no clinically significant residual angulation in radiographs. Two adolescents in the BIN group vs. none in the ESIN (P = 0.245) were excluded because of implant failure; another two with complete bone union suffered from re-injury. Therefore, satisfactory implant stability among older children needs to be studied.

In Vivo Three-Dimensional Analysis of Malunited Forearm Diaphyseal Fractures with Forearm Rotational Restriction.

BACKGROUND: The aim of this study was to clarify the mechanisms of rotational restriction in malunited forearm diaphyseal fractures. METHODS: We retrospectively analyzed the cases of 18 patients with malunited forearm diaphyseal fractures and rotational restriction. All patients underwent bilateral computed tomography (CT) of the forearm in maximum supination, pronation, and neutral positions. From these images, we created 3-dimensional (3-D) bone surface models. We quantified the 3-D deformities, identified instances of osseous impingement between the radius and the ulna during forearm rotation, calculated the path length of the central band (CB) of the interosseous membrane, and measured forearm range of motion. RESULTS: Sixteen patients had extension deformity of the radius (the RE group) and 2 had flexion deformity (the RF group). In the RE group, extension deformity of the radius and valgus deformity of the ulna had significant negative correlation with pronation range of motion (R = -0.50, p = 0.046) and supination range of motion (R = -0.63, p = 0.027), respectively. Osseous impingement was mainly observed during pronation (15 of 16 patients). The CB path with the largest changes in length originated from the distal CB attachment area of the radius and ran toward the proximal area of the ulna (the transverse CB). The transverse CB significantly increased in length in supination compared with that in pronation (p < 0.001). Therefore, tightness of the transverse CB appeared to cause supination restriction in the RE group. In the RF group, osseous impingement caused supination restriction. The greatest increases in the transverse CB length were observed in pronation in the RF group, which appeared to cause pronation restriction. CONCLUSIONS: In the RE group, pronation restriction was associated with osseous impingement that was due to extension deformity of the radius, and supination restriction was associated with CB tightness that was due to valgus deformity of the ulna. In the RF group, our results suggested that pronation restriction was caused by CB tightness and that supination restriction was caused by osseous impingement. CLINICAL RELEVANCE: Three-dimensional corrective osteotomy for extension deformity of the radius in malunited forearm diaphyseal fractures would improve rotational restriction by relieving osseous impingement during pronation and CB tightness during supination.

Treatment of posttraumatic bone defects of the forearm with vascularized fibular grafts. Follow up after fourteen years.

BACKGROUND: Among several techniques proposed for the reconstruction of posttraumatic bone defects of the forearm, that of free vascularised fibular graft (FVFG) is one of the most widely used. PATIENTS AND METHOD: We study the long-term outcomes of 14 patients who underwent FVFG between 1994 and 2009, with a minimum follow up of 8 years and a maximum of 23 years (mean: 13.9 years). Demographic, clinical and radiological variables were collected retrospectively. The DASH scale was used for clinical assessment. RESULTS: Fourteen patients were operated on by the same surgeon, applying FVFG for the reconstruction of posttraumatic bone defects of the forearm (three septic non-union of the ulna or radius, five radius fractures, two ulna fractures and four fractures of both bones). The maximum length of the defect was 11 cm and the minimum length was 6 cm. In four cases, reconstruction of the two bones was achieved using the double barrel technique, and in another four cases, an osteoseptocutaneous flap was used. Fixation was performed with 3.5 mm reconstruction plates in thirteen cases and with 3.5 mm screws in one case. Consolidation was obtained in 12 cases (85.7%) after an average time of 4.2 months (range: 2-6.5 months). In one case, consolidation of the proximal ulnar fracture site was not achieved, and in another, following the failure of reconstruction attempts, an arthrodesis was performed. At the end of the follow-up period, the patients had an average DASH score of 17.1 points (range 1.8-68.1). CONCLUSIONS: FVFG is a valid option for the reconstruction of posttraumatic bone defects of the forearm. Its use via the double barrel method or as an osteocutaneous composite graft enables the simultaneous reconstruction of both forearm bones and associated soft tissue injuries. Long-term follow-up of patients who have undergone this technique confirms its satisfactory functional and radiological results.

[Posttraumatic torsional deformities of the forearm : Methods of measurement and decision guidelines for correction]. / Posttraumatische Torsionsfehler am Unterarm : Messmethoden und Entscheidungsleitfaden für die Korrektur.

Forearm fractures are common in all age groups. Even if the adjacent joints are not directly involved, these fractures have an intra-articular character. One of the most common complications of these injuries is a painful limitation of the range of motion and especially of pronation and supination. This is often due to an underdiagnosed torsional deformity; however, in recent years new methods have been developed to make these torsional differences visible and quantifiable through the use of sectional imaging. The principle of measurement corresponds to that of the torsion measurement of the lower limbs. Computed tomography (CT) or magnetic resonance imaging (MRI) scans are created at defined heights. By searching for certain landmarks, torsional angles are measured in relation to a defined reference line. A new alternative is the use of 3D reformation models. The presence of a torsional deformity, especial of the radius, leads to an impairment of the pronation and supination of the forearm. In the presence of torsional deformities, radiological measurements can help to decide if an operation is needed or not. Unlike the lower limbs, there are still no uniform cut-off values as to when a correction is indicated. Decisions must be made together with the patient by taking the clinical and radiological results into account.

Comparing two methods to record maximal voluntary contractions and different electrode positions in recordings of forearm extensor muscle activity: Refining risk assessments for work-related wrist disorders.

BACKGROUND: Wrist disorders are common in force demanding industrial repetitive work. Visual assessment of force demands have a low reliability, instead surface electromyography (EMG) may be used as part of a risk assessment for work-related wrist disorders. For normalization of EMG recordings, a power grip (hand grip) is often used as maximal voluntary contraction (MVC) of the forearm extensor muscles. However, the test-retest reproducibility is poor and EMG amplitudes exceeding 100% have occasionally been recorded during work. An alternative MVC is resisted wrist extension, which may be more reliable. OBJECTIVE: To compare hand grip and resisted wrist extension MVCs, in terms of amplitude and reproducibility, and to examine the effect of electrode positioning. METHODS: Twelve subjects participated. EMG from right forearm extensors, from four electrode pairs, was recorded during MVCs, on three separate occasions. RESULTS: The group mean EMG amplitudes for resisted wrist extension were 1.2-1.7 times greater than those for hand grip. Resisted wrist extension showed better reproducibility than hand grip. CONCLUSIONS: The results indicate that the use of resisted wrist extension is a more accurate measurement of maximal effort of wrist extensor contractions than using hand grip and should increase the precision in EMG recordings from forearm extensor muscles, which in turn will increase the quality of risk assessments that are based on these.

Assessment of normal forearm compartment pressures in a Nigerian population.

PURPOSE: The forearm is prone to raised compartment pressure and it is the second most common site for compartment syndrome. The normal compartment pressure of the forearm should be known and serve as a benchmark for the diagnosis of acute and chronic compartment syndrome. This study was aimed to determine the normal compartment pressures of the forearm using a digital compartment pressure monitor. METHODS: This was a prospective hospital-based study of the uninjured forearm in 30 patients, who presented with closed unilateral forearm fracture at the accident and emergency department of a tertiary health care facility, between June 2012 and December 2013. Approval was sought and obtained from institutions ethical committee. An 18 gauge bevelled-tip needle, attached to a Compass TM digital compartment pressure monitor made by Mirador USA, was used to measure the pressures in the compartments of the forearm. Data obtained were analysed using the Stata 12. Significance was determined at p < 0.05. RESULTS: The mean age was 38.3 ± 18.3 years with male-to-female ratio of 2.3:1. The pressures in the volar compartment of the forearm ranged from 1 to 8 mmHg with a mean ± SD compartment pressure of 4.7 ± 1.5 mmHg. In the dorsal compartment the pressure ranged from 2 to 8 mmHg with a mean ± SD of 4.9 ± 1.7 mmHg SD, while the lateral compartment measurement ranged between 1 and 5 mmHg with a mean ± SD of 3.6 ± 1.1 mmHg. There was significant positive correlation (p < 0.01) between the compartment pressures in the volar, dorsal, and lateral compartments. CONCLUSION: The normal compartment pressure for forearm is 4.4 ± 1.6 mmHg and ranged from 1 to 8 mmHg from this study in our environment. This will serve as reference value when forearm compartment pressure is being measured.

Single- versus double-bundle suture button reconstruction of the forearm interosseous membrane for the chronic Essex-Lopresti lesion.

PURPOSE: Reconstruction of the ruptured interosseous membrane (IOM) is critical to restore forearm stability for the chronic Essex-Lopresti injury. Positive outcomes have been reported following IOM reconstruction with a single-bundle suture button (Mini-Tightrope) construct, although recent work suggests that double-bundle Mini-TightRope® IOM reconstruction is biomechanically superior. The purpose of this study was to determine whether double-bundle Mini-TightRope® reconstruction of the forearm IOM results in superior clinical outcomes to the single-bundle technique. METHODS: Five patients with chronic Essex-Lopresti injuries treated with double-bundle Mini-TightRope® IOM reconstruction were matched to five patients treated with single-bundle Mini-TightRope® reconstruction. Improvement in clinical examination measures and patient-reported outcomes was compared between the groups. RESULTS: Results were good to excellent in all 10 patients. At final follow-up, forearm rotation was significantly better in the single-bundle group, while maintenance of ulnar variance was better in the double-bundle group. No significant differences were noted between the two groups for any other numerical outcomes, and no complications occurred. CONCLUSION: These findings suggest that while IOM reconstruction with a double-bundle Mini-TightRope® construct results in greater resistance to proximal migration of the radius in the intermediate term, there is a modest concomitant loss of forearm rotation when compared to single-bundle reconstruction. LEVEL OF EVIDENCE: Therapeutic Level IV.

Long-term results of primary repair of combined cuts on the median and ulnar nerves in the forearm.

BACKGROUND: The objective of this clinical study was to evaluate sensory and motor functions in the later period following primary repair of combined injuries of the ulnar and median nerves in the forearm at proximal, middle, and distal levels. METHODS: Later period sensory evaluation of ulnar and median combined cuts was performed using two-point discrimination and monofilament tests. On the other hand, motor evaluation was performed by determining dorsal palmar interosseus strength for the ulnar nerve and abductor pollicis brevis muscle strength for the median nerve. Cold intolerance, object recognition, and weight discrimination were also reviewed. RESULTS: In total, 26 patients with ulnar-median combined cut and aged between 5 and 59 years were included in this study. Although no deficiency was observed in the sensory functions of any of the patients, a decrease in tactile sensation was detected in the median sensory region in 12 (46%) patients and in the ulnar sensory region in 7 (26%) patients. The most significant loss in terms of motor functions was detected in the opposition pinch strength. Two patients developed claw hand and two showed joint contracture. CONCLUSION: Ideal treatment for peripheral nerve injuries should be primary repair. Restoration of the motor function in the median nerve is relatively easier than that in the ulnar nerve. No significant difference was observed in terms of sensory function. An alternative is needed for primary repair because of lack of motor function in proximal ulnar incisions. There is no standardization of tests performed for peripheral nerve repair.

Intravenous regional anaesthesia (Bier's block) for pediatric forearm fractures in a pediatric emergency department-Experience from 2003 to 2014.

STUDY OBJECTIVES: To evaluate the efficacy (length of stay in the emergency department and failure rate of Bier's block) and safety profile (death and major complications) of Bier's block in its use for manipulation and reduction of paediatric forearm fractures. METHODS: This is a retrospective cohort study of pediatric patients in KKWomen's and Children's Hospital Children's Emergency Department with forearm fractures between Jan 2003 and Dec 2014 who underwent manipulation and reduction using Bier's block. Demographic data, time from registration to discharge, major complications and success rate were collated in a standardized data collection form. A subanalysis of the Bier's block group from 2009 to 2014 was performed and compared to a corresponding data set of paediatric patients who underwent manipulation and reduction of forearm fractures using ketamine for procedural sedation from 2009 to 2014. RESULTS: 1781 cases of paediatric forearm fractures were analysed. The mean age of patients in the Bier's block group was 12.0 years (range 5.5-17.8 years old). Of all patients undergoing Bier's block, 1471 out of 1781 patients were male (82.7%). The mean length of stay (LOS) in the department was 168±72min, measured from time of registration till departure. From our subanalysis of data from 2009 to 2014, the mean LOS for the Bier's block group was shorter - 170min compared to 238min for the ketamine group (P <0.0001). 2 patients had failed Bier's block which required a repeat procedural sedation using ketamine. 96% of patients who underwent Bier's block were discharged with an outpatient orthopaedic appointment. There were no deaths or major complications identified in our study. CONCLUSION: Bier's block is a safe technique for reduction of fractures when used in the appropriate population and fracture types, with a low failure rate and no major complications including death. Compared to the ketamine group, it has a shorter length of stay in the emergency department. We recommend the adoption of this practice for manipulation and reduction of pediatric forearm fractures in the Emergency Department with a formalised protocol to reduce and prevent any human errors that can potentially result in complications.