Metaphyseal-diaphyseal Junction Research Articles

Comparative outcomes of foot cast and short leg cast in pseudo-Jones avulsion fracture: a single blinded randomized controlled trial

BackgroundFractures of the metatarsal bones account for 35% of all foot fractures. Conservative management of fractures proximal to the metaphyseal-diaphyseal junction of the fifth metatarsal bone (pseudo-Jones) is by protected weight bearing. The methods of protected weight bearing include short-leg casting and splinting (boot cast, Jones’s bandage and elastic bandage). However, currently there is no consensus as to which method is the most suitable.MethodWe have conducted a randomized controlled trial to compare outcomes of foot casting (FC) and short leg casting (SLC) to assess pain, function and complication outcomes for the treatment of pseudo-jones metatarsal fractures. This single-center, single blind,randomized controlled trial was conducted between 1 June 2016–1 July 2018 at Police General Hospital, Bangkok, Thailand.ResultA total of 72 pseudo-jones metatarsal fracture participants were randomly allocated to treatment by foot cast or short leg cast. The primary outcomes were pain VAS, AOFAS and complications measured at 2, 4, 6 and 8 weeks after receiving the treatment. Seventy-two patients (36 paticipants per group) were enrolled to receive either FC or SLC. The mean VAS measured at baseline, 2 weeks, 4 weeks, 6 weeks and 8 weeks were 7.36, 1.97, 0.58, 0.17 and 0.08 respectively in the FC group; and 6.09, 2.91, 1.23, 0.37 and 0.11 respectively in the SLC group. The mean AOFAS at baseline, 2, 4, 6 and 8 weeks were 33.60, 68.22, 82.72, 91.75 and 98.11 respectively in the FC group; and 32.60, 60.20, 70.20, 92.24 and 99.13 in the SLC group. The estimated mean difference of pain VAS and AOFAS at 2 weeks and 4 weeks were − 0.94 (95% CI: − 1.53, − 0.34), − 0.65 (95%CI: − 1.24, − 0.05), 8.02 (95%CI: 3.74, 12.10) and 12.52 (95%CI: 8.27, 16.78), which were statistically significantly better in the FC groups when compared to the SLC groups. However, there were no statistically significant difference between the two groups at 6 and 8 weeks.ConclusionThis study demonstrated that the application of foot casting can improve pain VAS and AOFAS function at 2 and 4 weeks in the treatment of pseudo-jones metatarsal fractures when compared to short leg casting. However, at 6 and 8 weeks, there were no statistically significantly different between the two groups.

The elderly have similar outcomes compared to younger patients after ORIF with locking plate for comminuted proximal humerus fracture

ObjectiveThe aim of this study was to compare clinical and radiological outcomes of elder and younger patients with comminuted proximal humerus fracture treated with osteosynthesis with locking plate. MethodsA total of 70 patients (30 males and 40 females; mean age 65.4 years) operated on for Neer 3- or 4-part proximal humeral fractures between 2010 and 2016 and followed for at least one-year were included in the study. The reduction was achieved through intraosseous window to minimize soft tissue stripping in all patients and structural allograft at metaphyseal diaphyseal junction was used aggressively to resist varus force. Group 1 consisted of 32 patients aged 70 or older (14 males and 18 females; mean age: 77.8 ± 5.1), while Group 2 consisted of 38 patients younger than 70 (16 males and 22 females; mean age: 58.2 ± 9.3). The groups were compared for their clinical and radiological outcomes. ResultsThere was no significant difference in clinical outcomes by Oxford score (54.8 ± 2.7 vs 56.6 ± 3.4, p = 0.13) and ASES score (89.7 ± 5.7 vs 90.8 ± 8.2, p = 0.68). Two groups had similar radiological outcomes regarding neck shaft angle, greater tip height and offset. However, group 2 had better final shoulder forward elevation (162.6 ± 8.7 vs 135.4 ± 14.7ß, p < 0.05) and shorter duration to achieve maximal range of motion (4.37 ± 2.37 vs 8.14 ± 3.25 months, p < 0.05) than group 1. Two groups had similar complication rates (9.4% vs 7.9%). All the complications were related to greater tuberosity including mal-reduction and avulsion. ConclusionWith the prerequisite of good alignment with robust medial cortical support and untouched soft tissue over medial metaphysis area via intra-osseous reduction, comminution of proximal humeral fracture can achieve satisfactory result and low complication rate by osteosynthesis with locking plate system, regardless of age. In addition, we suggested to use structural bone graft for comminuted medial cortex fracture with multiple fragments or bony defect more than 2 cm. Level of evidenceLevel III Therapeutic study.

Jones Fracture in the Elite Athlete: Patient Reported Outcomes following Fixation with BMAC

Objectives:Jones’ fractures, 5th metatarsal metaphyseal-diaphyseal junction fractures, are a debilitating injury for the elite athlete, particularly in cutting/pivoting sports. These injuries are usually managed surgically due to the high rate of nonunion and re-fracture. Despite primary screw fixation, delayed union and nonunion are not uncommon. Bone marrow aspirate concentrate (BMAC), an autologous source of hematopoietic and mesenchymal stem cells, has been used to augment healing due to the poor healing potential in the watershed region. We hypothesize that open reduction internal fixation (ORIF) augmented with BMAC will improve patient-reported outcome measures following Jones’ fractures in athletes.Methods:This study was a prospectively collected and maintained review of elite athletes that underwent intramedullary screw fixation augmented with BMAC for Jones’ fractures at an academic medical institution. All patients were evaluated preoperatively and postoperatively to assess differences in patient reported outcomes including VAS, PROMIS, FAAM, SF-12 scores, return to play, and complications. Student’s t test was used in statistical comparison of the preoperative and postoperative outcome scores. P < 0.05 was considered significant.Results:A total of 41 elite athletes were treated with ORIF with BMAC for a Jones fracture with a mean age of 25.59 years (range 19-42). There were 26 (63%) males and 15 females included in the study. Type of athlete ranged across the following sport activities: football, basketball, soccer, volleyball. Of note, patients had significantly improved with lower visual analog score for pain (mean Δ3.56, p= 0.001), higher FAAM scores (mean Δ 43.6, p< 0.001), and PASS scores (increased from 11% to 85%, p< 0.001) at 6 months. Additionally, patients showed improvement in SF12, PROMIS10, and FAAM scores at 12 months, although this was not statistically significant due to insufficient follow up at this time. The average numbers of days lost to competition was 131 days. All patients that have returned to elite competitive sport activity report minimal to no pain.Conclusion:Intramedullary screw fixation of Jones’ fractures with BMAC results in optimal surgical outcomes in the elite athlete. The use of patient reported outcomes continues to be a focus of quality measures and should guide clinical decision making for surgical intervention, return to play, and to assess impact of treatment. A higher powered and long-term study with validated patient-reported outcomes is needed to confirm our observations.

Management of Fifth Metatarsal Fracture and Refracture in Athletes

Fractures of the proximal fifth metatarsal are very common in active individuals and elite athletes. Fractures may occur from a number of mechanisms, but inversion and twisting injuries are some of the most common causes. True Jones fractures are at the metaphyseal-diaphyseal junction and enter the fourth-fifth intermetatarsal articulation. Fractures in that area are at risk of delayed union or non-union, which can be extremely detrimental in elite athletes, because of the poor blood supply which results in a watershed area. Treatment recommendations depend on fracture location and acuity, as well as patient factors. Non-operative management can be successful, however delayed union and non-union may occur. Surgical stabilization of true Jones fractures is recommended in athletes and results in a low number of complications and a higher and more rapid rate of union much compared to non-operative methods. Overall, the treatment methods of fifth metatarsal fractures depend on a multitude of factors, however athletes benefit from more aggressive treatment regimens that result in high rates of union in less time.

Patient Reported Outcomes in Athletes following ORIF of Jones Fracture

Category: Lesser Toes, Midfoot/Forefoot, Sports Introduction/Purpose: Treatment of fractures to the 5th metatarsal metaphyseal-diaphyseal junction, known as Jones’ fractures, can present challenges in the elite athlete significantly prolonging return to play. Non-operative treatments in elite athletes result in a high incidence of nonunion and secondary fracture. Primary screw fixation remains the standard of care for athletes. However, delayed union and nonunion are still very common despite surgical fixation due to the fracture occurring in a watershed area with decreased healing potential. Bone marrow aspirate concentrate (BMAC) is an autologous source of hematopoeitic and mesenchymal stem cells that has been used in the treatment of poor healing fractures. We hypothesize that open reduction internal fixation (ORIF) augmented with BMAC will improve patient-reported outcome measures following Jones’ fractures in athletes. Methods: This study was a retrospective review of elite athletes that underwent intramedullary screw fixation augmented with BMAC for Jones’ fractures at an academic medical institution. All patients were assessed preoperatively and postoperatively to determine their pain outcomes based on their visual analog score (VAS). Student’s t test was used in statistical comparison of the preoperative and postoperative outcome scores. P &lt; 0.05 was considered significant. Results: A total of 16 elite athletes were treated with ORIF with BMAC for a Jones fracture with a mean age of 22.2 years (range 19–26). There were 9 males and 7 females included in the study. Type of athlete ranged across various sport activities, with all patients functioning at a collegiate and/or professional level of elite athletics. The mean visual analog score for pain decreased from 6.2 preoperatively (range 3-8) to 2.75 postoperatively (range 1-6 p = 0.06). All patients have returned to elite competitive sport activity with reports of minimal to no pain. Conclusion: Intramedullary screw fixation of Jones’ fractures with BMAC results in optimal surgical outcomes in the elite athlete. A higher powered and long-term study with validated patient-reported outcomes is needed to confirm our observations.

Erratum: Microstructure of the Distal Radius and Its Relevance to Distal Radius Fractures.

[This corrects the article DOI: 10.1055/s-0037-1602849.].

Microstructure of the Distal Radius and Its Relevance to Distal Radius Fractures.

Background There is a paucity of information on the microstructure of the distal radius, and how this relates to its morphology and function. Purpose This study aims to assess the microanatomical structure of the distal radius, and relate this to its morphology, function, and modes of failure. Methods Six dry adult skeletal distal radii were examined with microcomputed tomography scan and analyzed with specialist computer software. From 3D and 2D images, the subchondral, cortical, and medullary trabecular were assessed and interpreted based on the overall morphology of the radius. Results The expanded distal radial metaphysis provides a wide articular surface for distributing the articular load. The extrinsic wrist ligaments are positioned around the articular perimeter, except on the dorsal radial corner. The subchondral bone plate is a 2 mm multilaminar lattice structure, which is thicker below the areas of the maximal articular load. There are spherical voids distally, which become ovoid proximally, which assist in absorbing articular impact. It does not have Haversian canals. From the volar aspect of the lunate facet, there are thick trabecular columns that insert into the volar cortex of the radius at the metaphyseal-diaphyseal junction. For the remainder of the subchondral bone plate, there is an intermediate trabecular network, which transmits the load to the intermediate trabeculae and then to the trabecular arches. The arches pass proximally and coalesce with the ridges of the diaphyseal cortex. Conclusion The distal radius morphology is similar to an arch bridge. The subchondral bone plate resembles the smooth deck of the bridge that interacts with the mobile load. The load is transmitted to the rim, intermediate struts, and arches. The metaphyseal arches allow the joint loading forces to be transmitted proximally and laterally, providing compression at all levels and avoiding tension. The arches have a natural ability to absorb the impact which protects the articular surface. The distal radius absorbs and transmits the articular impact to the medullary cortex and intermediate trabeculae. The medullary arches are positioned to transmit the load from the intermediate trabeculae to the diaphysis. Clinical Relevance The microstructure of the distal radius is likely to be important for physiological loading of the radius. The subchondral bone plate is a unique structure that is different to the cancellous and cortical bone. All three bone types have different functions. The unique morphology and microstructure of the distal radius allow it to transmit load and protect the articular cartilage.

Proximal Fifth Metatarsal Fractures: Anatomy, Classification, Treatment and Complications.

ContextFractures of proximal fifth metatarsal are one of the most common fractures of the foot.Evidence AcquisitionA search of PubMed for studies on proximal fifth metatarsal fracture and Jones fracture focusing on the classification and management was performed. The reference list of the retrieved articles was searched for additional related studies.ResultsThe vascular supply and soft tissue anatomy of the fifth metatarsal explains the increased risk of delayed union and non-union in fractures at the metaphyseal-diaphyseal junction. Lawrence and Botte classify proximal fifth metatarsal fractures according to their location: tuberosity avulsion fractures (zone 1), fractures at metaphyseal-diaphyseal junction extending into the fourth-fifth intermetatarsal joint (zone 2) and proximal diaphyseal fractures (zone 3). Zone 1 fractures are treated conservatively with functional immobilization and early mobilization with excellent outcome. For zone 2 and zone 3 fractures, acute forms can be treated conservatively but with a risk of delayed union time and time for return to function. Therefore, early surgical fixation with intramedullary screw is advised in athletic individuals. For cases presented with signs of delayed union and non-union, surgical treatment with or without bone grafting is recommended. Complications of these fractures and their management are discussed in this report.ConclusionsLawrence and Botte’s classification of proximal fifth metatarsal fractures is recommended by experts, due to its implication on prognosis and treatment strategy. Zone 1 fractures should be treated conservatively due to their excellent healing potential. Early operative treatment is advised for zone 2 and zone 3 fractures, especially in the athletic group. Complications of delayed union, non-union and refractures should be treated by revision fixation and bone grafting.

Flexible Intramedullary Nailing of Pediatric Humeral Fractures: Indications, Techniques, and Tips.

Most proximal and diaphyseal pediatric humeral fractures can be treated successfully by closed means; however, certain patient factors or fracture characteristics may make surgical stabilization with flexible intramedullary nails (FIN) a better choice. Common indications for FIN of pediatric humeral fractures include unstable proximal-third fractures in children nearing skeletal maturity, unstable distal metaphyseal-diaphyseal junction fractures, shaft fractures in polytraumatized patients or patients with ipsilateral both-bone forearm fractures (floating elbow), and prophylactic stabilization of benign diaphyseal bone cysts or surgical stabilization of pathologic fractures. FIN can be safely inserted in an antegrade or retrograde manner depending on the fracture location and configuration. Careful dissection at the location of rod insertion can prevent iatrogenic nerve injuries. Rapid fracture union and return to full function can be expected in most cases. Implant prominence is the most common complication.

Length of Endoprosthetic Reconstruction in Revision Knee Arthroplasty Is Associated With Complications and Reoperations.

Complex revision total knee arthroplasty (TKA) often calls for endoprosthetic reconstruction to address bone loss, poor bone quality, and soft tissue insufficiency. Larger amounts of segmental bone loss in the setting of joint replacement may be associated with greater areas of devascularized tissue, which could increase the risk of complications and worsen functional results. Are longer endoprosthetic reconstructions associated with (1) higher risk of deep infection; (2) increased risk of reoperation and decreased implant survivorship; or (3) poorer ambulatory status? This is a single-institution retrospective case series of nononcologic femoral endoprosthetic reconstructions for revision TKA from 1995 to 2013 (n = 32). Cases were categorized as distal (n = 17) or diaphyseal (n = 15) femoral reconstructions based on extension to or above the supracondylar metaphyseal-diaphyseal junction, respectively. Five patients from each group were lost to followup before 2 years (distal mean 4 years [range, 2-8 years]; diaphyseal mean = 6 years [range, 2-16 years]), and one of the 12 distal reconstructions and two of the 10 diaphyseal reconstructions had not been evaluated within the past 5 years. Clinical outcomes and ambulatory status (able to walk or not) were assessed through chart review by authors not involved in any cases. Prior incidence of periprosthetic joint infection was high in both groups (distal = seven of 12 versus diaphyseal = four of 10; p = 0.670). Patients with diaphyseal femoral replacements were more likely to develop postoperative deep infections than patients with distal femoral replacements (distal = three of 12 versus diaphyseal = nine of 10; p = 0.004). Implant survivorship (revision-free) for diaphyseal reconstructions was worse at 2 years (distal = 100%, 95% confidence interval [CI], 100%-100% versus diaphyseal = 40%, 95% CI, 19%-86%; p = 0.001) and 5 years (distal = 90%, 95% CI, 75%-100% versus diaphyseal = 30%, 95% CI, 12%-73%; p = 0.001). Infection-free, revision-free survival (retention AND no infection) was worse for diaphyseal femoral replacing reconstructions than for distal femoral replacements at 2 years (distal = 70%, 95% CI, 48%-100% versus diaphyseal = 20%, 95% CI, 6%-69%; p = 0.037) and 5 years (distal = 70%, 95% CI, 48%-100% versus diaphyseal = 10%, 95% CI, 2%-64%; p = 0.012). There was no difference with the small numbers available in proportion of patients able to walk (distal reconstruction = eight of 11 versus diaphyseal = seven of 10; p = 1.000), although all but one patient in each group required walking aids. Endoprosthetic femoral reconstruction is a viable salvage alternative to amputation for treatment of failed TKA with segmental distal femoral bone loss. In our small series even with substantial loss to followup and likely best-case estimates of success, extension proximal to the supracondylar metaphyseal-diaphyseal junction results in higher infection and revision risk. In infection, limb salvage remains possible with chronic antibiotic suppression, which we now use routinely for all femoral replacement extending into the diaphysis. Level III, therapeutic study.

Outcome of Displaced Fractures of the Distal Metaphyseal-Diaphyseal Junction of the Humerus in Children Treated With Elastic Stable Intramedullary Nails.

The main objective of this study was to retrospectively evaluate the clinical and radiographic outcomes of displaced distal humeral metaphyseal-diaphyseal junction fractures in children treated by elastic stable intramedullary nailing (ESIN). During the study period, 14 consecutive children with fractures of the distal humeral metaphyseal-diaphyseal junction were surgically treated by ESIN. All patients underwent full-length preoperative and postoperative anteroposterior and lateral radiographs of the injured humerus. One year after the index surgery, patients were asked to answer the short version of the Disabilities of the Arm, Shoulder and Hand outcome questionnaire (Quick DASH). During the study period, fractures of the distal metaphyseal-diaphyseal humeral junction represented 1.5% (16/1100) of all humeral fractures. Fourteen patients underwent surgery and met the inclusion criteria. The male to female ratio was 1:1. The average patient age at the time of injury was 9.7 years (range, 3.6 to 13.7 y). The left and right sides were equally affected. The mean follow-up was 28.1 months (range, 20 to 38 mo).Radiologically, no secondary displacement, nail migration, loss of fixation, consolidation delay, nonunion, or refracture was noted. None of the patients showed signs of growth arrest on either radiologic or clinical assessment.All patients returned to their previous daily and sport activities without discomfort or difficulty, and they were free of pain at their last follow-up visits. The injured elbow range of motion was comparable with that of the contralateral side at the last follow-up visit in all patients. The mean Quick DASH score was 0.81 (range, 0 to 6.8). We recommend surgery for displaced fractures of the distal humeral metaphyseal-diaphyseal junction. ESIN results in stable reduction, good rotational control, and faster mobilization. Level IV.

Elbow fractures: from fixation to replacement

Distal humerus fractures may range from a simple extra-articular fracture pattern to a complex pattern, involving extensive destruction of the articular surface with comminution and bone loss in the metaphyseal-diaphyseal junction of the bone. The management decision in the younger patient requires complete anatomical reconstruction and early active range of motion. Different approaches to the distal humerus will be discussed, as will be different fixation methods. I will also present relevant clinical cases and outline the known outcomes of these fractures. In the elderly with osteoporotic fractures especially those with preexisting arthritis, there is an emerging trend for primary total elbow replacement. The outcomes of such replacement have been shown to be comparable to those of total elbow replacement in arthritis. However, there have been a few complications reported in the literature and this method is best reserved for complex comminuted distal humerus fractures in patients with significant osteoporosis and those above the age of 70. I will also discuss complex fracture dislocations of the elbow joint in terms of the management decisions and outcomes of these difficult problems.

Angular stable lateral plating is a valid alternative to conventional plate fixation in the proximal phalanx. A biomechanical study

BackgroundDorsal plating is commonly used in proximal phalanx fractures but it bears the risk of interfering with the extensor apparatus. In this study, dorsal and lateral plating fixation methods are compared to assess biomechanical differences using conventional 1.5mm non-locking plates and novel 1.3mm lateral locking plates. MethodsTwenty-four fresh frozen human cadaveric proximal phalanges were equally divided into four groups. An osteotomy was set at the proximal metaphyseal–diaphyseal junction and fixed with either dorsal (group A) or lateral (group B) plating using a 1.5mm non-locking plate, or lateral plating with a novel 1.3mm locking plate with bicortical (group C) or unicortical (group D) screws. The specimens were loaded in axial, dorsovolar and mediolateral direction to assess fixation stiffness followed by a cyclic destructive test in dorsovolar loading direction. FindingsAxial stiffness was highest in group D (mean 321.02, SEM 21.47N/mm) with a significant difference between groups D and B (P=0.033). Locking plates (groups C and D) were stiffer than non-locking plates under mediolateral loading (P=0.007), no significant differences were noted under dorsovolar loading. Furthermore, no significant differences were observed under cyclic loading to failure between any of the study groups. InterpretationNo considerable biomechanical advantage of using a conventional 1.5mm dorsal non-locking plate was identified over the novel 1.3mm lateral locking plate in the treatment of proximal phalanx fractures. Since the novel low-profile plate is less disruptive to the extensor mechanism, it should be considered as a valid alternative.

Screw Fixation Diameter for Fifth Metatarsal Jones Fracture: A Cadaveric Study

The fifth metatarsal Jones fracture is a well-documented injury occurring at the proximal diaphyseal-metaphyseal junction. Conservative versus surgical intervention has been discussed in published studies for the management of Jones fractures. Solid intramedullary fixation relies on accurate matching of the screw diameter to the intraosseous diameter. The purpose of the present cadaveric study was to determine the average intraosseous diameter of the proximal fifth metatarsal as it relates to screw size selection for Jones fracture stabilization. Twenty fresh-frozen cadaver legs were used for examination. The fifth metatarsal was completely dissected. A transverse osteotomy was performed from laterally to medially along the midline of the metatarsal. A digital caliper was used to measure the diameter of the medullary canal of the fifth metatarsal. The measurement was taken at the narrowest portion of the medullary canal just distal to the proximal metaphysis. The mean dorsal to plantar diameter of the fifth metatarsal was 6.475 ± 1.54 (range 4 to 12) mm and the mean medial to lateral diameter was 4.6 ± 0.85 (range 3 to 6) mm. Intramedullary screw fixation has shown beneficial results in the treatment protocol of fifth metatarsal Jones fractures. Our study has demonstrated that a 4.5-mm cannulated screw is the narrowest diameter screw that can be used in the average fifth metatarsal and still obtain adequate intraosseous purchase. When selecting the appropriate screw, the surgeon must be comfortable selecting the largest screw that will achieve the maximal interface with the dense cortical bone in both the medial to lateral and dorsal to plantar plane.

Revision of a fractured uncemented revision stem using a custom designed punch and retrograde through-knee approach.

We report a unique case of a fractured modular cobalt chromium connection taper Revitan (Zimmer, Warsaw, IN) revision prosthesis. Macroscopic examination revealed a fracture at the diaphyseal-metaphyseal junction of this modular component. This report highlights that fractures can still occur with modern modular prostheses. We are not aware of any published failures of the Revitan revision prosthesis. We also describe a unique method of retrieval for a broken well fixed uncemented femoral stem, using a custom designed extraction instrument via a through-knee approach.

Controversies in the intramedullary nailing of proximal and distal tibia fractures.

Management of tibia fractures by internal fixation, particularly intramedullary nails, has become the standard for diaphyseal fractures. However, for metaphyseal fractures or those at the metaphyseal-diaphyseal junction, choice of fixation device and technique is controversial. For distal tibia fractures, nailing and plating techniques may be used, the primary goal of each being to achieve acceptable alignment with minimal complications. Different techniques for reduction of these fractures are available and can be applied with either fixation device. Overall outcomes appear to be nearly equivalent, with minor differences in complications. Proximal tibia fractures can be fixed using nailing, which is associated with deformity of the proximal short segment. A newer technique-suprapatellar nailing-may minimize these problems, and use of this method has been increasing in trauma centers. However, most of the data are still largely based on case series.

Prebending of a titanium elastic intramedullary nail in the treatment of distal radius fractures in children.

The aims of this study were to introduce a method to treat distal radius diaphyseal metaphyseal junction fractures by prebending an elastic intramedullary nail and to evaluate the factors influencing fracture apposition. Fifty-two consecutive patients (4 to 15 years old) with a distal radius diaphyseal metaphyseal junction fracture were included. The nail was inserted and advanced into the proximal radial fragment as normal. After bending the nail distally about 90° at the site predetermined to lie at the distal segment, the elastic intramedullary nail was advanced until the prebent part completely entered the marrow cavity. The fracture angular deformity was fully corrected in anterior-posterior and lateral views. The apposition rate was 90% to 100% in lateral view, >50% in anterior-posterior view. The operation time was 16.73 ± 6.253 minutes. The average time of fracture healing was 5 months (range, 4-7 months). During 12 to 19 months of follow-up, firm fracture healing and good remodeling were observed, and there was no impaired forearm rotation function or secondary fracture. Our study showed the treatment of distal radius diaphyseal metaphyseal junction fractures by prebent intramedullary nail could make up for the deficiency of Kirschner wires and steel plates and keep the fracture stable. Fracture type and the anatomical features of the distal radius were associated with fracture apposition.

Periosteal PTHrP regulates cortical bone modeling during linear growth in mice.

The modeling of long bone surfaces during linear growth is a key developmental process, but its regulation is poorly understood. We report here that parathyroid hormone-related peptide (PTHrP) expressed in the fibrous layer of the periosteum (PO) drives the osteoclastic (OC) resorption that models the metaphyseal-diaphyseal junction (MDJ) in the proximal tibia and fibula during linear growth. PTHrP was conditionally deleted (cKO) in the PO via Scleraxis gene targeting (Scx-Cre). In the lateral tibia, cKO of PTHrP led to a failure of modeling, such that the normal concave MDJ was replaced by a mound-like deformity. This was accompanied by a failure to induce receptor activator of NF-kB ligand (RANKL) and a 75% reduction in OC number (P ≤ 0.001) on the cortical surface. The MDJ also displayed a curious threefold increase in endocortical osteoblast mineral apposition rate (P ≤ 0.001) and a thickened cortex, suggesting some form of coupling of endocortical bone formation to events on the PO surface. Because it fuses distally, the fibula is modeled only proximally and does so at an extraordinary rate, with an anteromedial cortex in CD-1 mice that was so moth-eaten that a clear PO surface could not be identified. The cKO fibula displayed a remarkable phenotype, with a misshapen club-like metaphysis and an enlargement in the 3D size of the entire bone, manifest as a 40-45% increase in the PO circumference at the MDJ (P ≤ 0.001) as well as the mid-diaphysis (P ≤ 0.001). These tibial and fibular phenotypes were reproduced in a Scx-Cre-driven RANKL cKO mouse. We conclude that PTHrP in the fibrous PO mediates the modeling of the MDJ of long bones during linear growth, and that in a highly susceptible system such as the fibula this surface modeling defines the size and shape of the entire bone.

A novel technique for accurate Poller (blocking) screw placement

Achieving good results with intramedullary nailing of oblique long bone fractures at the metaphyseal–diaphyseal junction can be difficult. There is a strong tendency for axial displacement and an association with characteristic malalignment of the short fragment. Poller or blocking screws have been shown to be effective in aiding fracture reduction. While several papers describe methods for screw placement, these are confusing to understand, difficult to follow in clinical practice and not always applicable. Here we describe a new, simple, reproducible and easy to use method for ensuring accurate Poller screw placement, in order to maximise the benefits of their use and achieve good overall results.

Treatment of osteonecrosis in the knee joint of a rabbit using autologous cultured osteoblasts

BackgoundTo develop a successful treatment modality for osteonecrosis, an appropriate animal model is essential. We have proposed a new osteonecrosis model that shows the total amount of necrosis and in which we observed new bone formation after transplanting autologous cultured osteoblasts. Materials and methodsThe femoral condyles of the right knees of New Zealand white rabbits were exposed after dissecting the ligaments surrounding the distal femur. After which, the metaphyseal–diaphyseal junction was cut using a saw, and the entire femoral condyle was isolated. After three liquid nitrogen treatments, the isolated femoral condyle was internally fixated to the femoral shaft using two or three Kirschner wires. Bone marrow isolated from the iliac crest was cultivated to differentiate it into osteoblasts, and the cultured cells were then injected into the necrotic bone. ResultsViable osteocytes with well-stained nuclei were not present in the necrotic areas at any stage of the development of the osteonecrosis model within 24 wk after osteonecrosis induction. However, new bone formation with osteocytes and blood vessels was observed in the necrotic bone 12 wk after transplanting the autologous cultured osteoblasts. ConclusionsThe distal femoral condyle of the rabbit is an appropriate model for demonstrating osteonecrosis and treatment evaluation owing to its easy reproducibility and treatment interpretation. Therefore, autologous cultured osteoblast treatment would seem to be a potentially successful treatment modality for osteonecrosis.