Obese Children Have Different Forearm Fracture Characteristics Compared With Normal-weight Children.

BACKGROUND: Current estimates suggest that one third of children and adolescents are overweight and 1 in 5 are obese. Obese children are at increased risk of sustaining more complex fractures, failing nonoperative treatment, and experiencing more complications during treatment. The purpose of this study was to compare forearm fracture characteristics, treatment, and complications in grouped overweight and obese [OW+OB; body mass index-for-age percentile (BMI%) ≥85] pediatric patients compared with normal-weight (NW; BMI%≤84) patients. METHODS: This was a retrospective comparative study of patients aged 2 to 17 years old who presented with a forearm fracture resulting from low-energy trauma between January 2010 and September 2017. Patients with incomplete height and weight data; an underlying condition that predisposes to fractures or altered fracture healing; and torus, greenstick, pathologic, and high-energy fractures were excluded. Demographics, fracture characteristics, treatment, and complications were recorded. Descriptive and inferential analyses were conducted. RESULTS: A total of 565 patients (403 NW, 162 OW+OB) met the inclusion criteria. NW children sustained open fractures nearly twice as frequently as the OW+OB children but this was not statistically significant (9.7% vs. 4.9%; P=0.065). Subanalysis showed that NW children were 4.1 times more likely to sustain an open fracture compared with obese (BMI%≥95) children (9.7% vs. 2.4%; P=0.029). A significant relationship was found between BMI% and location of the fracture, the bones involved, and fracture type. The OW+OB children sustained more distal forearm fractures than midshaft and proximal forearm fractures. Isolated radial shaft fractures were more common in the OW+OB group, whereas isolated ulnar shaft fractures were more common in the NW group. There was no difference in associated neurovascular injury, initial nonoperative versus operative management, failure of nonoperative treatment, and treatment complications. CONCLUSIONS: OW+OB children have different forearm fracture characteristics compared with their NW peers. The thick soft tissue envelope in obese children may be protective against an open forearm fracture. In contrast to previous studies, obesity was not associated with failure of nonoperative treatment or a higher rate of complications. LEVEL OF EVIDENCE: Level III-prognostic.

Pronation type Galeazzi-equivalent fracture: A rare case report (CARE-compliant).

RATIONALE: Galeazzi fractures are uncommon, and are less common in children than in adults. Galeazzi-equivalent fractures, a variant of the classic Galeazzi fractures, mostly occur in children or adolescents. Galeazzi equivalent fractures may commonly accompany distal radial fractures or injury of the epiphyseal plate of the distal ulna. PATIENT CONCERNS: A 13-year-old man visited our emergency department after stumbling over a rock. Manual reduction and splinting was already done in a nearby medical center. Plain radiographs revealed fractures in the distal radius and fracture of the ulnar epiphyseal plate. DIAGNOSIS: Plain radiographs showed Galeazzi-equivalent fracture. The result of primary closed reduction was not enough and there was still displacement of fracture. INTERVENTIONS: Anatomical reduction of distal radius was fixed with a plate and screws, and K-wires were inserted percutaneously for reduction and fixation of ulnar fracture. OUTCOMES: Complete bone union was achieved and normal range of motion is shown 2 years postoperatively. The patient is able to perform daily activities and sport activities without any signs of ulnar growth arrest. LESSONS: Open reduction is required in patients with malalignment, failure to reduce the DRUJ or maintain its reduction, or older ages which are hard to expect sufficient bone remodeling.

A Biomechanical Comparison of Three Miniature Locking Plate Systems in a Rabbit Radial and Ulnar Fracture Model.

OBJECTIVE: The aim of this study was to evaluate the biomechanical properties of three different miniature locking plate systems used to fixate radial and ulnar fractures in toy breed dogs. Implant size, shape, material and locking systems differ, and their influence on the fracture healing process is unknown. In the present study, we aimed to investigate this matter in vivo using rabbit radial and ulnar fracture models. STUDY DESIGN: Eighteen rabbits were randomly divided into three groups, and the left radius and ulna were osteotomized to create fracture models. The osteotomies were then fixated using either the TITAN LOCK 1.5, Fixin micro or LCP 1.5 system. Radiographs were obtained 2, 3 and 4 weeks after surgery. Four weeks after surgery, the radiuses were collected and used for biomechanical testing or histological examinations. RESULTS: During the 4 weeks of observation, no adverse effects due to the implants occurred. The radiographic scores in each group did not differ significantly at any time point. The maximum load in the LCP group was significantly higher than that in the TITAN and Fixin groups. There was no significant difference in bending stiffness or work to failure among the groups. Initial fracture healing via woven bone was evident at histological evaluation. CONCLUSIONS: All three miniature locking plate systems provided adequate fracture stabilization 4 weeks after surgery, despite their differences, in rabbit models.

Spatiotemporal Distribution of Linear Microcracks and Diffuse Microdamage Following Daily Bouts of Fatigue Loading of Rat Ulnae.

Microdamage accumulation contributes to impaired skeletal mechanical integrity. The bone can remove microdamage by initiating targeted bone remodeling. However, the spatiotemporal characteristics of microdamage initiation and propagation and their relationship with bone remodeling in response to fatigue loading, especially for more physiologically relevant daily bouts of compressive loading, remain poorly understood. The right forelimbs of 24 rats were cyclically loaded with a ramp waveform for 1,500 cycles/day, and contralateral ulnae were not loaded as the controls. The rats were divided into four equal groups and loaded for 1, 4, 7, and 10 days, respectively. We demonstrated that linear microcracking accumulation exhibited a non-linear time-varying process within 10 days of loading with peaked microcrack density at Day 7. Disrupted canaliculi surrounding linear microcracks showed high similarity with the temporal changes of linear microcracking accumulation. Observable intracortical resorption regions were found on Day 10. We found more linear microcracks accumulated in the tensile cortex, but longer cracks were observed in the compressive sides. Increased accumulation of diffuse microdamage was observed from Day 4, but no obvious peak was observed within the 10-day loading period. Diffuse damage first initiated in the compressive cortices but extended to tension from Day 7. The diffuse damage exhibited no impacts on the surrounding osteocyte integrity. Together, our findings revealed a time-dependent, bone remodeling-mediated varying process of linear microcracking accumulation following daily bouts of fatigue loading (with observable peak at Day 7 under our loading regime). Our study also identified distinct spatial accumulation of linear and diffuse microdamage in rat ulnae with tensile and compressive strains. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2112-2121, 2019.

Nightstick Fractures, Outcomes of Operative and Non-Operative Treatment.

INTRODUCTION: A nightstick fracture is an isolated fracture of the ulnar shaft. Although operative and non-operative treatments have been commonly decided by the degree of displacement of the fracture, still there is a controversy specially in those moderately displaced. Herein we report our experience with nightstick fractures. OBJECTIVE: To evaluate operative and non-operative treatment of nightstick fracture. MATERIALS AND METHODS: We retrospectively reviewed the clinical notes, physiotherapy letters and radiographs of 52 patients with isolated ulnar shaft fractures. Outcome Measurements included radiographic healing, post-operative range of motion and complications. RESULTS: The study included 13 females and 39 males, with a mean age of 26 years [range, 18-93 years]. The mean Follow-up period was 32 months ranged from 12 to 54 months. Ten patients were treated non-operatively; forty-two patients had open reduction and internal fixation including six open fractures. The average wait for surgery was 2.5 days. Mobilisation was commenced immediately after the surgeries non-load bearing. 40 patients had no complications post-operatively with good outcome and average of four visits follow-up. In the non-operative group, five out ten failed and had a mean follow-up of nine visits. CONCLUSION: Satisfactory outcome is to be expected with open reduction and internal fixation. Fractures with less than 50% displacement should be treated on individual bases, considering; age, pre-morbid functional status, co-morbidities, compliance and associated injuries.

Evaluation of Bone Atrophy After Treatment of Forearm Fracture Using Nonlinear Finite Element Analysis: A Comparative Study of Locking Plates and Conventional Plates.

PURPOSE: Forearm diaphysis fractures are usually managed by open reduction internal fixation. Recently, locking plates have been used for treatment. In the long-term period after surgery, some patients present with bone atrophy adjacent to the plate. However, a comparison of locking and conventional plates as a cause of atrophy has not been reported. The aim of this study was to investigate long-term bone atrophy associated with use of locking and conventional plates for forearm fracture treatment. METHODS: In this study we included 15 patients with forearm fracture managed by either locking or conventional plates and with more than 5 years of follow-up. Computed tomographic imaging of both forearms was performed to assess bone thickness and local bone mineral density and to predict bone strength without plate reinforcement based on finite element analysis. RESULTS: Mean patient age at surgery was 48.0 years. Eight patients underwent reduction with fixed locking plates and were followed up for a mean of 79.5 months; the remaining 7 patients were treated with conventional plates and were followed up for a mean of 105.0 months. Compared with the conventional plate group, the locking plate group had the same fractured limb-contralateral limb ratio of cortex bone thickness, but had significantly lower ratios of mineral density adjacent to the plate and adjusted bone strength. CONCLUSIONS: This study demonstrated bone atrophy after locking plate fixation for forearm fractures. Treatment plans for forearm fracture should take into consideration the impact of bone atrophy long after plate fixation. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Concomitant injury of the annular ligament in fractures of the coronoid process and the supinator crest.

BACKGROUND: Fractures of the coronoid process or the supinator crest, as well as arthroscopic resection of osteophytes around the coronoid process, can endanger the attachment of the annular ligament (AL) to the proximal ulna. The purpose of this study was to investigate the corresponding insertional areas of the AL within this context. METHODS: In 30 embalmed human cadaveric elbow specimens, the insertional area of the AL at the anterior and posterior margin of the sigmoid notch was characterized. The distances and relations of the AL insertion anteriorly to the coronoid surface, the coronoid tip, and the depth of the coronoid process, as well as posteriorly to the supinator crest, were evaluated macroscopically. RESULTS: The mean distance of the anterior insertion area was 1.9 ± 0.6 mm (range, 1.0-3.1 mm) to the coronoid articular surface and 6.2 ± 1.7 mm (range, 2.9-10.2 mm) to the tip of the coronoid. The distance of the anterior insertion in relation to the depth of the coronoid process was 44% ± 11% (range, 30%-69%). The distance of the posterior insertion area to the level of the sigmoid notch measured from 3.5 ± 1.5 mm (range, 0.5-6.5 mm) to 17.7 ± 2.9 mm (range, 13.1-25.4 mm). CONCLUSIONS: Coronoid fractures involving 44% or more of the coronoid process and anterolaterally oriented fractures where one-third of the anterolateral facet is affected are accompanied by a complete anterior bony disruption of the AL. Arthroscopic resection of the coronoid tip should be limited to 1 mm distal to the coronoid articular surface to avoid injury to the AL. Fractures of the upper half of the supinator crest place the AL at risk at its posterior insertion.

Morphological characteristics of olecranon fractures in adults : a Computed Tomography-based study.

The aim of this study was to identify the fragment's shape by evaluating olecranon fractures. We examined the CT images of 48 olecranon fractures (28 women and 20 men). Mean age was 59.9 years. On the olecranon's posterior surface, we measured the distance between the apex of the olecranon fragment and the radial edge of the flat spot on the short axis and the width of the flat spot on the same short axis. The tip radial ratio (i.e., the tip radial edge to the flat spot width) was derived from these parameters. The mean tip radial edge was 1.96 mm, and the flat spot width was 12.64 mm ; therefore, the tip radial ratio was 0.15 mm. Radial inclination on the articular surface was 30.55°. Our findings confirmed our hypothesis that the fracture lines run from the proximal ulnar side to the distal radial side on the olecranon's posterior and articular surfaces.

Evaluation of outcomes in aseptic non-unions of the forearm bones in adults treated with LCP and autograft.

BACKGROUND: The aim of the present study was to evaluate the effect of locking compression plate (LCP) and autografting application in patients with nonunion of forearm fractures on radiologic and clinical outcome. METHODS: A total of 26 patients (16 males, 10 females; mean age: 45.7 years) with nonunion after surgical treatment of forearm fractures were included. Nonunion was located in the ulna in 14 patients, in the radius in 5 patients, and in both in 7 patients (21 ulna, 12 radius).Infection markers were checked prior to surgery. Samples for microbiologic cultures were peroperatively obtained in 7 patients with a history of open fractures. Autografting from the iliac crest and 3.5-mm LCP were applied. Type of nonunion, time to unification, range of motion in the wrist and elbow joints, and complications were analyzed. Functional evaluation was performedusing the scoring system described by Anderson et al. RESULTS: Mean follow-up period was 49.3 months (range 24-73 months). Unification was achieved in a mean 5.7 months (range 3-14 months). Additional surgical process was not required. No bacterial proliferation was observed in cultures. Superficial infection was observed in 3 patients and deep infection in 1. Results were scored as excellent in 10 (38.4%) patients, satisfactory in 13 (50%), and unsatisfactory in 3 (11.6%). CONCLUSION: Treatment of aseptic forearm nonunion in adults with autografting from the iliac crest and 3.5-mmLCP fixation increases unification rate and aids in function recovery.

The effect of strontium ranelate on the healing of a fractured ulna with bone gap in rabbit.

BACKGROUND: Fracture healing in bone gap is one of the major challenges encountered in Orthopedic Surgery. At present, the treatment includes bone graft, employing either internal or external fixation which has a significant impact on the patient, family and even society. New drugs are emerging in the markets such as anabolic bone-forming agents including teriparatide and strontium ranelate to stimulate bone growth. Based on the mechanism of their actions, we embarked on a study on the healing of a fractured ulna with bone gap in a rabbit model. We segregated ten rabbits into two groups: five rabbits in the test group and five rabbits in the control group. We created a 5 mm bone gap in the ulna bone, removing the periosteum as well. Rabbits in the test group received 450 mg/kg of strontium ranelate via oral administration, daily, for six weeks. The x-rays, CT scans and blood tests were performed every two weeks. At the end of six weeks, the rabbits were sacrificed, and the radius and ulna bones harvested for histopathological examination. RESULTS: Based on the x-rays and CT scans, fracture healing or bone formation was observed to be faster in the control group. From the x-ray findings, 80 % of the fracture united and by CT scan, 60 % of the fracture united in the control group at the end of the six-week study. None of the fractures united in the test group. However, the histopathology report showed that a callus of different stages was being formed in both groups, consisting of 80 % of bone. The serum levels of osteocalcin and alkaline phosphatase initially remained similar up to three weeks and changed slightly at the end of six weeks. CONCLUSIONS: We conclude that the strontium effect begins slowly, and while it may not interfere with bone cell proliferation it may interfere in the mineralization and delay the acute stage of fracture healing. We recommend that a larger sample size and a longer duration of the study period be implemented to confirm our finding.

Medical thermography (digital infrared thermal imaging - DITI) in paediatric forearm fractures - A pilot study.

Trauma is the most common cause of hospitalisation in children, and forearm fractures comprise 35% of all paediatric fractures. One-third of forearm fractures are distal forearm fractures, which are the most common fractures in the paediatric population. This type of fracture represents an everyday problem for the paediatric surgeon. The three phases of fracture healing in paediatric trauma are associated with skin temperature changes that can be measured and then compared with standard plain radiographs of visible callus formation, and eventually these methods can be used in everyday practice. Thermographic assessment of temperature distribution within the examined tissues enables a quick, non-contact, non-invasive measurement of their temperature. Medical thermography is used as a screening method in other parts of medicine, but the use of this method in traumatology has still not been researched.

Bone engineering by phosphorylated-pullulan and ß-TCP composite.

A multifunctional biomaterial with the capacity bond to hard tissues, such as bones and teeth, is a real need for medical and dental applications in tissue engineering and regenerative medicine. Recently, we created phosphorylated-pullulan (PPL), capable of binding to hydroxyapatite in bones and teeth. In the present study, we employed PPL as a novel biocompatible material for bone engineering. First, an in vitro evaluation of the mechanical properties of PPL demonstrated both PPL and PPL/ß-TCP composites have higher shear bond strength than materials in current clinical use, including polymethylmethacrylate (PMMA) cement and α-tricalcium phosphate (TCP) cement, Biopex-R. Further, the compressive strength of PPL/ß-TCP composite was significantly higher than Biopex-R. Next, in vivo osteoconductivity of PPL/ß-TCP composite was investigated in a murine intramedular injection model. Bone formation was observed 5 weeks after injection of PPL/ß-TCP composite, which was even more evident at 8 weeks; whereas, no bone formation was detected after injection of PPL alone. We then applied PPL/ß-TCP composite to a rabbit ulnar bone defect model and observed bone formation comparable to that induced by Biopex-R. Implantation of PPL/ß-TCP composite induced new bone formation at 4 weeks, which was remarkably evident at 8 weeks. In contrast, Biopex-R remained isolated from the surrounding bone at 8 weeks. In a pig vertebral bone defect model, defects treated with PPL/ß-TCP composite were almost completely replaced by new bone; whereas, PPL alone failed to induce bone formation. Collectively, our results suggest PPL/ß-TCP composite may be useful for bone engineering.

External fixation in the elderly.

Orthopaedic trauma is an increasingly common problem in geriatric patients. As demands of daily life and recreational activities are increasing in these patients, surgeons need to be able to manage geriatric fractures to achieve good functional results. Reduced bone quality in the elderly presents a considerable challenge and may preclude the use of established surgical stabilisation techniques that are performed in younger trauma patients. Furthermore, pre-existing medical conditions and considerable comorbidities in the elderly could complicate standard surgical procedures that younger patients would be offered. In this respect, application of external fixators represents a validated, minimally-invasive treatment opportunity. This review article summarises the use of external fixation in geriatric trauma patients for wrist fractures, proximal femoral fractures, pelvic fractures, and ankle fractures. Modern modifications, like pin coating with hydroxyapatite, and aspects of pin care will be discussed.

Complex proximal ulna fractures: outcomes of surgical treatment.

BACKGROUND: To review the results of plating of various fracture patterns of proximal ulna fractures including isolated olecranon fractures, olecranon fractures combined with a coronoid fracture, and olecranon fractures combined with a coronoid and radial head fracture. MATERIALS AND METHODS: The study included 38 patients with either an isolated olecranon fracture or combined injuries, all treated with open reduction and internal fixation of the olecranon. Other procedures were performed as needed, including radial head fixation or arthroplasty, fixation of the coronoid, and repair of the lateral collateral ligament complex. There were 27 men and 11 women with an average age of 49 years. Clinical and radiographic assessment was obtained at an average follow-up time of 15 and 8.4 months, respectively. RESULTS: All fractures healed within 5 months. The average arc of ulnohumeral motion was 91° (range 0°-140°); average pronation-supination arc was 128° (range 0°-180°). Subgroup analysis showed a statistically significant lower rotational motion arc in patients with associated radial head (73°) or coronoid fractures (68°) compared to isolated olecranon fractures. All other parameters including ulnohumeral motion, complication rate, and revision rate were similar among the groups. CONCLUSIONS: A stable, functional elbow can be restored in most patients with proximal ulna fractures treated with open reduction and internal fixation. Loss of full flexion is likely with high-energy trauma, complex fracture patterns, and concomitant injuries. Fracture patterns involving the coronoid and/or the radial head are associated with restricted forearm rotation. LEVEL OF EVIDENCE: III.

Formación de un solo hueso en antebrazo, en pseudoartrosis infectada de cúbito proximal / Formation of a single bone in the forearm in infected pseudoarthrosis of the proximal ulna

Propósito: Presentar el resultado exitoso de la técnica de formación de un solo hueso en antebrazo en un paciente con fractura inicial de cúbito con múltiples osteosíntesis e injertos fallidos. Caso: Paciente masculino dedicado a labores del campo que, a los 39 años de edad, sufre fractura de cúbito izquierdo, después de una evolución de 13 años y 5 intervenciones quirúrgicas con diversos tipos de osteosíntesis e injertos fallidos, que finalizaron en seudoartrosis infectada de cúbito izquierdo, decidiendo efectuarle la formación de un solo hueso en antebrazo evolucionando satisfactoriamente en función. Actualmente: supinación de 20º de antebrazo, flexoextensión de codo y muñeca completas, fuerza muscular adecuada, actualmente integrado en su trabajo de campo sin limitaciones funcionales. Conclusión: La técnica de formación de un solo hueso en antebrazo es, en casos adecuadamente seleccionados, una excelente alternativa de cirugía de reconstrucción o de salvamento en extremidad torácica.

Purpose: To present the successful results of the single-bone reconstruction technique in the forearm in a patient who sustained an ulnar fracture and underwent multiple osteosyntheses and failed grafts. Case: Male patient, agricultural worker, who at age 39 sustained a left ulnar fracture. After 13 years and 5 surgeries involving different types of osteosyntheses and failed grafts, which resulted in infection of the left ulnar pseudoarthrosis, we decided to do a single-bone reconstruction of the forearm. He did well and achieved good function. His current status is: 20º of forearm supination, full elbow and wrist flexion and extension, appropriate muscle strength, and he returned to his job without functional limitations. Conclusion: The single-bone forearm reconstruction technique is, in properly selected cases, an excellent surgical alternative when reconstruction or salvage of the thoracic limb is required.

In vivo study of magnesium plate and screw degradation and bone fracture healing.

Each year, millions of Americans suffer bone fractures, often requiring internal fixation. Current devices, like plates and screws, are made with permanent metals or resorbable polymers. Permanent metals provide strength and biocompatibility, but cause long-term complications and may require removal. Resorbable polymers reduce long-term complications, but are unsuitable for many load-bearing applications. To mitigate complications, degradable magnesium (Mg) alloys are being developed for craniofacial and orthopedic applications. Their combination of strength and degradation make them ideal for bone fixation. Previously, we conducted a pilot study comparing Mg and titanium devices with a rabbit ulna fracture model. We observed Mg device degradation, with uninhibited healing. Interestingly, we observed bone formation around degrading Mg, but not titanium, devices. These results highlighted the potential for these fixation devices. To better assess their efficacy, we conducted a more thorough study assessing 99.9% Mg devices in a similar rabbit ulna fracture model. Device degradation, fracture healing, and bone formation were evaluated using microcomputed tomography, histology and biomechanical tests. We observed device degradation throughout, and calculated a corrosion rate of 0.40±0.04mm/year after 8 weeks. In addition, we observed fracture healing by 8 weeks, and maturation after 16 weeks. In accordance with our pilot study, we observed bone formation surrounding Mg devices, with complete overgrowth by 16 weeks. Bend tests revealed no difference in flexural load of healed ulnae with Mg devices compared to intact ulnae. These data suggest that Mg devices provide stabilization to facilitate healing, while degrading and stimulating new bone formation.

[Formation of a single bone in the forearm in infected pseudoarthrosis of the proximal ulna]. / Formación de un solo hueso en antebrazo, en pseudoartrosis infectada de cúbito proximal.

PURPOSE: To present the successful results of the single-bone reconstruction technique in the forearm in a patient who sustained an ulnar fracture and underwent multiple osteosyntheses and failed grafts. CASE: Male patient, agricultural worker, who at age 39 sustained a left ulnar fracture. After 13 years and 5 surgeries involving different types of osteosyntheses and failed grafts, which resulted in infection of the left ulnar pseudoarthrosis, we decided to do a single-bone reconstruction of the forearm. He did well and achieved good function. His current status is: 20° of forearm supination, full elbow and wrist flexion and extension, appropriate muscle strength, and he returned to his job without functional limitations. CONCLUSION: The single-bone forearm reconstruction technique is, in properly selected cases, an excellent surgical alternative when reconstruction or salvage of the thoracic limb is required.

[Arthroscopy of the distal radioulnar joint]. / Die Arthroskopie des distalen Radioulnargelenks.

OBJECTIVE: Insertion of a small joint arthroscope into the proximal and distal parts of the distal radioulnar joint (DRUJ) allows visualization of the proximal pouch of the DRUJ, the joint surfaces of the sigmoid notch and the ulnar head, the convexity of the ulnar head and the proximal ulnar-sided surface of the triangular fibrocartilage complex (TFCC). INDICATIONS: Evaluation of joint pathologies in ulnar-sided wrist pain, especially in cases without diagnostic findings in standard X-rays and MRI, suspected cartilage lesions without osteochondral changes (signs of osteoarthritis), undefined swelling of the DRUJ in suspected synovitis, removal of loose bodies and arthroscopical synovialectomy, suspected lesions of the deep part of the TFCC, respectively foveal avulsions, wear or superficial tears of the proximal TFCC and arthroscopic-assisted ulnar shortening. CONTRAINDICATIONS: Significant changes of the local topographical anatomy, extensive scar formation, ulna plus variance, local infection or open wounds, affected sensibility in the area of the dorsal branch of the ulnar nerve, fractures of the sigmoid notch or the ulnar head, capsular tears causing effusion of irrigation fluid. SURGICAL TECHNIQUE: In vertical extension of the wrist, two portals are created on the dorsal side of the DRUJ between the extensor digiti minimi and extensor carpi ulnaris tendons. Partial visualization of the ulnar head, the sigmoid notch, the proximal pouch of the DRUJ, and the proximal surface of the TFCC. POSTOPERATIVE MANAGEMENT: Following isolated diagnostic arthroscopies immobilization of the wrist in a semicircular ulnar-sided cast for 1 week. No extensive load to the wrist for 4 weeks. RESULTS: Still rarely performed procedure for diagnosis and therapy of ulnar-sided wrist pain. Technically demanding with a flat learning curve and anatomy-related obstacles. A complete view of the joint is not always accessible. Rare complications are injuries of the extensor digiti minimi tendon as well as contusion or sectioning of the transverse branch of the dorsal branch of the ulnar nerve. In distinct cases this procedure offers valuable additional information about the distal radioulnar joint.

Structural and mechanical repair of diffuse damage in cortical bone in vivo.

Physiological wear and tear causes bone microdamage at several hierarchical levels, and these have different biological consequences. Bone remodeling is widely held to be the mechanism by which bone microdamage is repaired. However, recent studies showed that unlike typical linear microcracks, small crack damage, the clusters of submicron-sized matrix cracks also known as diffuse damage (Dif.Dx), does not activate remodeling. Thus, the fate of diffuse damage in vivo is not known. To examine this, we induced selectively Dif.Dx in rat ulnae in vivo by using end-load ulnar bending creep model. Changes in damage content were assessed by histomorphometry and mechanical testing immediately after loading (ie, acute loaded) or at 14 days after damage induction (ie, survival ulnae). Dif.Dx area was markedly reduced over the 14-day survival period after loading (p < 0.02). We did not observe any intracortical resorption, and there was no increase in cortical bone area in survival ulnae. The reduction in whole bone stiffness in acute loaded ulnae was restored to baseline levels in survival ulnae (p > 0.6). Microindentation studies showed that Dif.Dx caused a highly localized reduction in elastic modulus in diffuse damage regions of the ulnar cortex. Moduli in these previously damaged bone areas were restored to control values by 14 days after loading. Our current findings indicate that small crack damage in bone can be repaired without bone remodeling, and they suggest that alternative repair mechanisms exist in bone to deal with submicron-sized matrix cracks. Those mechanisms are currently unknown and further investigations are needed to elucidate the mechanisms by which this direct repair occurs.