Application of a combined cancellous lag screw enhances the stability of locking plate fixation of osteoporotic lateral tibial plateau fracture by providing interfragmentary compression force.

BACKGROUND: Insufficient interfragmentary compression force (IFCF) frequently leads to unstable fixation of osteoporotic lateral tibial plateau fractures (OLTPFs). A combined cancellous lag screw (CCLS) enhances IFCF; however, its effect on OLTPF fixation stability remains unclear. Therefore, we investigated the effect of CCLS on OLTPF stability using locking plate fixation (LPF). MATERIALS AND METHODS: Twelve synthetic osteoporotic tibial bones were used to simulate OLTPFs, which were fixed using LPF, LPF-AO cancellous lag screws (LPF-AOCLS), and LPF-CCLS. Subsequently, 10,000 cyclic loadings from 30 to 400 N were performed. The initial axial stiffness (IAS), maximal axial micromotion of the lateral fragment (MAM-LF) measured every 1000 cycles, and failure load after 10,000 cycles were tested. The same three fixations for OLTPF were simulated using finite element analysis (FEA). IFCFs of 0, 225, and 300 N were applied to the LPF, LPF-AOCLS, and LPF-CCLS, respectively, with a 1000-N axial compressive force. The MAM-LF, peak von Mises stress (VMS), peak equivalent elastic strain of the lateral fragment (EES-LF), and nodes of EES-LF > 2% (considered bone destruction) were calculated. RESULTS: Biomechanical tests revealed the LPF-AOCLS and LPF-CCLS groups to be superior to the LPF group in terms of the IAS, MAM-LF, and failure load (all p < 0.05). FEA revealed that the MAM-LF, peak VMS, peak EES-LF, and nodes with EES-LF > 2% in the LPF were higher than those in the LPF-AOCLS and LPF-CCLS. CONCLUSION: IFCF was shown to enhance the stability of OLTPFs using LPF. Considering overscrewing, CCLS is preferably recommended, although there were no significant differences between CCLS and AOCLS.

Reoperation rate and implants' position variation features of displaced femoral neck fractures with sliding compression or length-stable fixation in young and middle-aged population.

INTRODUCTION: Sliding compression fixation and length-stable fixation are two basic internal fixation concepts in the treatment of displaced femoral neck fractures. In this study, we aimed to compare the reoperation rates for different methodologies of internal fixation for femoral neck fractures in young and middle-aged population. MATERIALS AND METHODS: This a retrospective study. A total of 215 patients with displaced femoral neck fractures treated with cannulated screw fixation were enrolled and divided into the sliding compression and length-stable groups according to the fixation pattern. The occurrence of and reason for revision surgery within one year were recorded. Forty-five patients with complete CT data (including CT scanning on the first postoperative day and at the last follow up) were selected from the total sample. A newly established computerized image processing method was used to evaluate variations in the spatial location of screws. RESULTS: The reoperation rate was significantly higher in the length-stable group (23.8%) than in the sliding compression group (7.3%). The rate of revision surgery due to nonunion was also higher in the length-stable group (11.4%) than in the sliding compression group (1.8%). However, no significant difference was observed in terms of joint penetration or soft tissue irritation. The sliding compression group (6.58 ± 3.18 mm) showed higher femoral neck shortening than length-stable group (4.16 ± 3.65 mm). When analyzing the spatial variations, a significantly greater screw withdrawal distance was observed in the sliding compression group than in the length-stable group, but with a smaller rotation angle. CONCLUSION: Length-stable internal fixation of displaced femoral neck fractures may lead to an increased reoperation rate in young and middle-aged population. TRIAL REGISTRATION: Name of the registry: Chinese Clinical Trial Registry. TRIAL REGISTRATION NUMBER: ChiCTR2000032327. Trial registration date: 2020-4-26.

Does tibial design modification improve implant stability for total knee arthroplasty? An experimental cadaver study.

AIMS: One of the main causes of tibial revision surgery for total knee arthroplasty is aseptic loosening. Therefore, stable fixation between the tibial component and the cement, and between the tibial component and the bone, is essential. A factor that could influence the implant stability is the implant design, with its different variations. In an existing implant system, the tibial component was modified by adding cement pockets. The aim of this experimental in vitro study was to investigate whether additional cement pockets on the underside of the tibial component could improve implant stability. The relative motion between implant and bone, the maximum pull-out force, the tibial cement mantle, and a possible path from the bone marrow to the metal-cement interface were determined. METHODS: A tibial component with (group S: Attune S+) and without (group A: Attune) additional cement pockets was implanted in 15 fresh-frozen human leg pairs. The relative motion was determined under dynamic loading (extension-flexion 20° to 50°, load-level 1,200 to 2,100 N) with subsequent determination of the maximum pull-out force. In addition, the cement mantle was analyzed radiologically for possible defects, the tibia base cement adhesion, and preoperative bone mineral density (BMD). RESULTS: The BMD showed no statistically significant difference between both groups. Group A showed for all load levels significantly higher maximum relative motion compared to group S for 20° and 50° flexion. Group S improved the maximum failure load significantly compared to group A without additional cement pockets. Group S showed a significantly increased cement adhesion compared to group A. The cement penetration and cement mantle defect analysis showed no significant differences between both groups. CONCLUSION: From a biomechanical point of view, the additional cement pockets of the component have improved the fixation performance of the implant. Cite this article: Bone Joint Res 2022;11(4):229-238.

Mechanical effects of surgical variations in the femoral neck system on Pauwels type III femoral neck fracture : a finite element analysis.

AIMS: In this study, we aimed to explore surgical variations in the Femoral Neck System (FNS) used for stable fixation of Pauwels type III femoral neck fractures. METHODS: Finite element models were established with surgical variations in the distance between the implant tip and subchondral bone, the gap between the plate and lateral femoral cortex, and inferior implant positioning. The models were subjected to physiological load. RESULTS: Under a load of single-leg stance, Pauwels type III femoral neck fractures fixed with 10 mm shorter bolts revealed a 7% increase of the interfragmentary gap. The interfragmentary sliding, compressive, and shear stress remained similar to models with bolt tips positioned close to the subchondral bone. Inferior positioning of FNS provided a similar interfragmentary distance, but with 6% increase of the interfragmentary sliding distance compared to central positioning of bolts. Inferior positioning resulted in a one-third increase in interfragmentary compressive and shear stress. A 5 mm gap placed between the diaphysis and plate provided stability comparable to standard fixation, with a 7% decrease of interfragmentary gap and sliding distance, but similar compressive and shear stress. CONCLUSION: Finite element analysis with FNS on Pauwels type III femoral neck fractures revealed that placement of the bolt tip close to subchondral bone provides increased stability. Inferior positioning of FNS bolt increased interfragmentary sliding distance, compressive, and shear stress. The comparable stability of the fixation model with the standard model suggests that a 5 mm gap placed between the plate and diaphysis could viably adjust the depth of the bolt. Cite this article: Bone Joint Res 2022;11(2):102-111.

Poller (blocking) screw with intramedullary femoral nailing for subtrochanteric femoral non-unions: clinical outcome and review of concepts.

INTRODUCTION: Surgery to treat nonunion resulted from malalignment is challenging since correction and bone union should be achieved simultaneously. To report the clinical outcomes achieved through reconstruction of sub-trochanteric femoral fractures by femoral nailing using a poller screw and to review the current concepts. MATERIALS AND METHODS: Fourteen patients (11 men and 3 women; mean age 56.4 years) who were diagnosed with non-union of subtrochanteric femoral fractures and who underwent intramedullary nailing with blocking screws between August 2013 and March 2019, with at least 1 year follow-up, were analyzed retrospectively. The preoperative and postoperative Centrum-Collum-Diaphyseal angle and anterior angulation angle were measured. Bone union time, position and number of poller screws used, and complications were analyzed. Functional assessment was performed by evaluating the Harris hip score. The related literature was searched, and 14 clinical studies on the treatment of sub-trochanteric non-union were analyzed. RESULTS: Bone union was achieved in 12/14 cases (85.7%) at the final follow-up within a mean of 6.52 (3-12) months. Bone union was also achieved in two patients lacking bone union at the final follow-up through bone grafting and augmented plating. No cases developed complications, including infection and bone necrosis, and the varus deformity and anterior angulation significantly improved from a preoperative mean of 12.4° and 9.4° to postoperative mean 3.8° and 2.4°, respectively. The mean Harris hip score at the final follow-up was 87.07 (73-98) points. Analysis of published literature revealed high rates of bone union (78-100%) through various fixation methods. CONCLUSION: Correction with blocking screws and rigid fixation with intramedullary nailing to treat sub-trochanteric-non-union-caused malalignment can yield good clinical and radiological outcomes.

Femoral shaft healing disorder biomechanics and biology case report.

Nonunion is one of the common fracture healing complications. Its diagnosis is based on clinical and X-ray/CT findings. Nonunions can be classified, according to Weber and Cech, as vital and nonvital. Low mechanical stability is the main underlying factor in the development of vital nonunions and therefore, the treatment should be focused on increasing their stability. Absence of biological activity is the causal factor in the development of nonvital nonunions; thus the therapy must be bolstered by bone grafting and decortication. Treatment of nonunions is time consuming and costly and the frequency of their incidence is not decreasing. However, significant progress has been made in the treatment of patients with this bone healing defect over the last decades owing to improved understanding of its genesis and the development of osteosynthetic materials. The presented case of nonunion after periprosthetic fracture includes a detailed description of the therapeutic considerations and techniques used in subsequent phases of treatment, accompanied by radiologic and pictorial documentation. Six months after application of a wave plate, the nonunion was successfully healed. The wave plate is a rarely used implant in our countries; however, its specific biomechanical and biological characteristics significantly support healing of indicated diaphyseal nonunions.

Analysis of Factors Affecting Return to Work After Surgical Treatment in Patients with AO Type C Distal Humerus Fractures.

BACKGROUND: The purpose of this study is to evaluate the functional results of distal humerus fractures which were treated by open reduction and fixation with pre-contoured angular stable plates in young patients, and investigate whether the patients could return to their pre-injury work and patients' financial conditions while they were not working. MATERIALS AND METHODS: The data of 48 patients, ages between 18 and 55 years, working in a job and having AO/OTA type C distal humerus fracture were retrospectively evaluated. Mayo Elbow Performance Score (MEPS) was used to determine functional results. Postoperative radiographs were evaluated to determine the rate of union, degenerative changes, malunion and heterotopic ossification. Financial outcome form was constituted by the authors and the patients asked whether she/he could return to their pre-injury works after treatment finished and the financial status of the patients during the treatment and after the treatment. RESULTS: The mean flexion-extension arc was 114° ± 12°(range 85°-135°) and the mean MEPS score was 85 ± 11(range 65-100). The average time to return to work was 6.5 ± 2.4 months (3-12 months). AO type C2 and C3 fractures and heterotopic ossification negatively affected the functional results and also adversely affected the patients' return to their pre-injury works. 38 (79%) patients returned to pre-injury work and 29 (76%) of them started to work at the same position before the fracture occured. Nine of 38 patients (24%) had to change their positions. Among the 48 patients, 10 patients (21%) could not return to the same work, 7 of them found light duty and 3 of them had not been to work. CONCLUSION: Although the functional results of surgical treatment of intra-articular distal humerus fractures are good, at the end of the treatment, especially heavy workers may have difficulties in returning to their former works.

[Closed reduction and internal fixation of pediatric femoral neck fractures]. / Geschlossene Reposition und perkutane Osteosynthese der Schenkelhalsfraktur im Kindesalter.

OBJECTIVE: To achieve anatomical reduction and stable fixation. Preservation of the proximal femoral physis is in this regard secondary. INDICATIONS: Nondisplaced and displaced femoral neck fractures Delbet types II and III. Incomplete fractures are debatable. No age restrictions. CONTRAINDICATIONS: Any patient condition that does not allow for general or regional anesthesia. Pathologic fractures requiring primarily an open approach. SURGICAL TECHNIQUE: Anatomical reduction is achieved via axial tension, internal rotation and gentle abduction or flexion of the affected hip and verified under image intensification; several stab incisions or a small single incision (3 cm) laterally at the level of the lesser trochanter to determine the entry points for the K­wires or screws; inserting and positioning the K­wires either as a configuration of two or three; depending on the bony dimensions fixation of the fracture with the K­wires or replacing them with cannulated screws; the localization of the main fracture line (basicervical or subcapital) determines whether the implants should cross the physis. POSTOPERATIVE MANAGEMENT: Partial weight bearing/touch ground (about 20% of bodyweight) for 6 weeks; either by using crutches or via mobilization in buggy or wheelchair. RESULTS: As an example, we present a case of a 9-year-old girl suffering from a displaced femoral neck fracture (Delbet type II) on the left side, who underwent closed reduction and internal screw fixation. Fracture healing and follow-up until today were uneventful. A brief review of the published literature is also provided.

Posterior pelvic ring injury of straddle fractures: Incidence, fixation methods, and clinical outcomes.

Straddle fracture, a superior and inferior ramus fracture of both sides, is generally treated conservatively. However, posterior pelvic ring injury is often associated with straddle fracture, leading to unstable pelvic bone fracture that requires surgical treatment. The present study reports the clinical and radiological outcomes of straddle fracture with posterior pelvic ring injury. This study included 73 patients (41 men, 32 women) with a straddle fracture injury. The injury mechanism, injury severity score (ISS), accompanying injuries, presence of posterior pelvic ring injury, and fixation methods for the pelvic fracture were analyzed, and outcomes were evaluated functionally and radiologically. Of the 73 patients, 56 (77%) had a posterior pelvic ring injury and 7 died. In 43 patients, the posterior pelvic ring injuries constituted unstable pelvic injury and were treated surgically. The fixation method was determined based on the severity of the posterior pelvic injury. The patients' mean ISS was 24.7 points. Radiological evaluation of surgical outcomes in 43 patients revealed the outcomes as anatomic in 20, nearly anatomic in 14, moderate in 5, and poor in 4, whereas functional evaluation revealed the outcomes as excellent in 21, good in 9, fair in 7, and poor in 6. Posterior pelvic ring fracture can accompany straddle fractures, which may lead to pelvic injury instability. Thus, special attention is required for patients with a straddle fracture.

Angular stable fixation of displaced distal-third clavicle fractures with superior precontoured locking plates.

HYPOTHESIS: We reviewed the outcome of angular stable plates in addressing displaced lateral-third clavicle fractures. We investigated union, shoulder function, request for implant removal, and return to sport. Our hypothesis was that these implants provide predictable union and return to sports without the negative consequence of leaving plates in situ, reducing the requirement for a second surgery. METHODS: We undertook a retrospective review of a consecutive series of patients who underwent this surgery between 2007 and 2010. Nineteen patients with a mean follow-up of 25 months were included. Postoperative follow-up was performed at 2 weeks and monthly thereafter until union was assessed as achieved clinically and radiographically. Two telephone interviews at a mean of 7 months and 25 months postoperatively assessed shoulder function by Oxford Shoulder Score, presence of any plate or scar discomfort, need for implant removal, and return to sport. RESULTS: Nineteen patients achieved union by 4 months (median, 12 weeks; range, 6-16 weeks). The mean Oxford Shoulder Score was 46 (range, 41-48) at a mean of 7 months (range, 3-18 months) and 47 (range, 44-48) at 25 months (range, 18-48 months). Initially, 2 patients requested implant removal; later, however, both declined surgery. No plates have been removed. Four patients complained of mild plate discomfort but did not wish removal. All patients had returned to sporting activities. CONCLUSION: Angular stable plate fixation of Neer group II, type II clavicle fractures resulted in a 100% union rate with excellent return of function with no mandatory need for removal.

Effect of fixation on neovascularization during bone healing.

Fixation and vascularity after bone fracture are two critical factors for successful healing, and their influences on bone healing have been studied by many researchers. This research aims to obtain three-dimensional (3D) reconstruction images of neovascularization of the soft tissues surrounding the fracture with vascular perfusion and micro-computer tomography (micro-CT) imaging, and to investigate the effect of stable fixation on neovascularization and the pattern of vascularity during the process of bone healing. To accomplish this, 36 Sprague-Dawley (SD) rats underwent mid-shaft transverse osteotomy of the right tibia. Half of them received stable fixation with a newly custom-designed external fixator (FSF, the group of fracture with stable fixation), while the rest received no fixation (FNF, the group of fracture with no fixation). The results indicated that FNF samples had more transversal vascular distribution than FSF samples; FSF samples had more longitudinal vascular distribution than FNF samples; and the spatio-temporal pattern of vascularity in FSF samples was more similar to that in the control group (CON, the group without fracture) than that in FNF samples. At the time of 2 and 4 weeks postoperatively, FNF samples had significantly higher vessel volume ratio (VV/TV), larger vessel number (VN) and higher vessel surface density (VS/TV) than CON samples. At all sacrifice times, FSF samples contained significantly higher VV/TV, VN and VS/TV values compared with FNF samples. In summary, neovascularization and its pattern are obviously influenced by the mechanical fixation. Stable fixation can promote longitudinal vascularity pattern formation, which tends to be similar to the natural vascularity pattern, and this benefits the inter-fragmentary blood fluid connectivity during bone healing process.

Radiographic and clinical evaluations of the zygomatico-maxillary complex fractures treated by 2. 0 miniplates system / Evaluaciones radiográficas y clínicas de fracturas del complejo cigomáticomaxilar tratadas por el sistema de mini placas 2. 0

The zygomaticomaxillary complex (ZMC) is the second highly incidental of facial fractures. According to the anatomical complexity, there are many reports in the literature about this trauma, mainly related to treatment for these fractures. With the purpose of evaluating clinically and radiographically the stability of unilateral zygomatic fractures treated by surgical reduction and fixed in two points by stable internal fixation, this research was proposed. Twenty patients with zygomatic fractures were evaluated and compared with twenty nonfractured patients. The results showed that there were no statistically significant differences among the obtained data, perimeter and area, of the treated and contra-lateral sides of the experimental group. When compared to the control group the differences were not statistically significant. We also performed a comparison of the distance between the nasal bone and zygomatic prominence in all groups the results were also satisfactory

Las fracturas del complejo cigomaticomaxilar son las segundas más frecuente del territorio facial. De acuerdo con la complejidad anatómica, existen muchos informes en la literatura sobre este trauma, principalmente relacionadas con el tratamiento de estas fracturas. El propósito de esta investigación fue evaluar clínica y radiográficamente la estabilidad de las fracturas cigomáticas unilaterales tratadas por reducción quirúrgica y fijadas en dos puntos por fijación interna estable. Veinte pacientes con fracturas cigomáticas fueron evaluados y comparados con veinte pacientes sin fracturas. En el grupo experimental, los resultados mostraron que no hubo diferencias estadísticamente significativas entre los datos obtenidos del perímetro y el área de los lados tratados y contralaterales. Al comparar estos datos con el grupo de control las diferencias no fueron estadísticamente significativas. También se realizó una comparación de la distancia entre el hueso nasal y la prominencia cigomática en todos los grupos, estos resultados también fueron satisfactorios

Promising results after the treatment of simple and complex distal humerus type C fractures by angular-stable double-plate osteosynthesis.

INTRODUCTION: The aim of this study was to evaluate the functional results and complications following open reduction and internal fixation of distal humerus type C fractures (AO classification) using an anatomically precontoured, angular-stable double-plate system. PATIENTS AND METHODS: The study is a retrospective analysis of 45 patients with 46 type C fractures. There was one C1, eight C2 and 31 C3 fractures. Twelve fractures were open (Gustilo classification). Follow-up was performed on 38 patients with 39 fractures (84%) after 14 months (range, 12-22). The mean age was 50 years (range, 14-87). Functional results were evaluated using the Mayo Elbow Performance Score (MEPS); the Disabilities of the Arm, Shoulder and Hand score (DASH); and range-of motion (ROM) measurements. Complications were classified as minor or major, and the postoperative and follow-up X-rays were analyzed. RESULTS: Thirty-four fractures were considered stable to allow early physical therapy. With a mean MEPS of 85 points, 36 results (36/39 [92%]) were rated as excellent or good. The mean DASH was 22.5 points, and the ROM for extension-flexion was 105° (range, 50-145). Sixteen major complications (eventually coexistent: 6 × implant failure, 3 × non-union, 6 × stiffness, 2 × necrosis capitulum, 4 × failure olecranon osteotomy refixation) and two minor complications were recorded in 17 patients. These adverse events led to 14 revision surgeries (14/39 [36%]). Except for extension deficit, no statistically significant differences were found between the articular simple and articular complex fractures and when comparing the results between patients with and without a major complication. CONCLUSION: The anatomically precontoured and angular-stable double-plate system provides sufficient immediate postoperative stability to allow early physiotherapy, even in C3-type fractures. Excellent or good results could be achieved in the vast majority of patients, independent on having suffered a complication or not. Complication rates were remarkably high, emphasizing the difficulties associated with this rare type of fracture. LEVEL OF EVIDENCE: Level IV Retrospective study.