Comparative biomechanical analysis of reconstruction and cephalomedullary nails in the treatment of osteoporotic subtrochanteric fractures.

INTRODUCTION: This study aimed to compare the biomechanical properties of two types of intramedullary nails - reconstruction nails (RCN) and cephalomedullary nails (CMN) - each with different proximal fixations, in a model of an osteoporotic subtrochanteric femoral fracture. This study focused on assessing stiffness and load to failure of RCN and CMN nails to provide insight into their clinical applications in osteoporotic fracture treatments. MATERIALS AND METHODS: Ten synthetic osteoporotic femoral models were used to generate a comminuted subtrochanteric fracture model. Five femurs were fixed using an RCN, and the remaining five were fixed using a CMN. The constructs were subjected to axial compression to measure their structural stiffness, load to failure, and failure modes. RESULTS: The CMN group demonstrated a slightly higher load to failure (mean, 2250 N) than the RCN group (mean, 2100 N), which was statistically significant (p = 0.008). However, the stiffness in both groups was statistically similar (RCN, 250 N/mm; CMN, 255 N/mm; p = 0.69). Both groups showed a load to failure exceeding 1500 N, a typically exerted load on the femoral head by a 75 kg individual. The failure patterns differed, with CMN failures starting at the nail insertion area and RCN failures starting at the reconstruction screw area. CONCLUSION: The RCN offers stiffness comparable to that of the CMN; although its load to failure is slightly lower than that of the CMN, it still exceeds the physiological tolerance limit. These findings suggest that the RCN is a viable alternative for treating osteoporotic subtrochanteric fractures.

Induced membrane technique with plate fixation has a lower complication rate than bone transport over a plate for segmental tibial defects larger than 5 cm.

INTRODUCTION: The treatment of segmental tibial bone defects remains a surgical challenge. While Bone Transport (BT) and Induced Membrane Technique (IMT) are effective strategies for regenerating bone, there are few comparative studies between them. This investigation undertakes a comparative analysis of BT and IMT for large segmental tibial defects stabilised through plate fixation. MATERIALS AND METHODS: Patients with segmental tibial defects exceeding 5 cm were prospectively enrolled from 2008 to 2021 in a single institution, with a minimum follow-up duration of two years. All patients underwent either BT or IMT with plate fixation of the tibia. Procedural success, primary union as well as bone and functional outcome scores were compared. Complications, including non-unions, joint contractures and deep infections requiring surgical intervention, were also compared. RESULTS: 41 patients were recruited in total. 28 patients underwent Bone Transport Over a Plate (BTOP), while 13 patients underwent IMT with Plate fixation (IMTP). The procedural success rate trended higher in IMTP compared to BTOP (100% vs. 85.7%). The primary union rate also trended higher in IMTP compared to BTOP (92.3% vs. 79.2%). BTOP and IMTP achieved similar rates of satisfactory bone outcome scores (78.6% vs. 84.6%) and functional outcome scores (75% vs. 76.5%). There was no statistical difference between procedural success, primary union, bone and functional outcome scores. The complication rate in BTOP was 78.6% (22 of 28), including five docking site or regenerate non-unions, eight deep infections and nine joint contractures. IMTP had a 38.5% (5 of 13) complication rate, including one non-union, two deep infections and two joint contractures. The complication rate was 2.04 times higher in BTOP compared to IMTP (p = 0.0117). CONCLUSIONS: BTOP and IMTP are both equally effective techniques for regenerating bone in large tibial bone defects. However, IMTP may be a safer procedure than BTOP, with a lower probability of requiring additional procedures to address complications.

Does preoperative bone marrow edema affect clinical outcomes after medial open-wedge high tibial osteotomy?

PURPOSE: The aim of this study is to evaluate the results of high tibial osteotomy (HTO) in patients with bone marrow edema (BME) and assess the effect of factors on the subsequent results. METHODS: A total of 138 patients who underwent medial open-wedge HTO using locking plate were included in this study. BME was observed in 108 patients using preoperative magnetic resonance imaging. Clinical results were evaluated before HTO and postoperatively at 12 months. Moreover, we evaluated the factors affecting the clinical results. RESULTS: The clinical scores were all significantly improved regardless of the presence of BME. There were no differences in improvement of clinical scores between patients with BME and without BME. Patients with BME showed higher postoperative Western Ontario and McMaster Universities Arthritis Index (WOMAC) stiffness scores than patients without BME. Furthermore, patients with BME on both the femur and tibia showed lower Knee Society function scores than patients with BME on either the femur or the tibia. Patients with large BME lesions exhibited a lower Hospital for Special Surgery score and WOMAC pain scores, postoperatively. In patients with BME, patients with undercorrection showed significantly lower improvement in WOMAC pain scores compared with patients with acceptable correction. CONCLUSIONS: The clinical improvement after HTO in patients with varus and medial osteoarthritis was not different regardless of the presence or absence of BME. However, accurate alignment should be considered essential for achieving better clinical outcomes in patients with preoperative BME.

Comparing outcomes of plate augmentation, nail exchange, and nail exchange with plate augmentation in the treatment of atrophic femoral shaft nonunion after intramedullary nailing: a multicenter retrospective study.

INTRODUCTION: Intramedullary (IM) nailing is the treatment of choice for femoral shaft fractures, but nonunion rates have been reported to be as high as 12%. Surgical interventions for nonunion involve exchange nailing or plate augmentation. Recently, a combined treatment of exchange nailing and plate augmentation has demonstrated good results, but its comparative effectiveness remains unclear. This study aimed to compare the clinical and radiographic outcomes of three different surgical interventions for atrophic femoral shaft nonunion, and investigate the factors that affect bone healing after reoperation. MATERIALS AND METHODS: A retrospective study was conducted at five university hospitals involving 149 patients with aseptic atrophic nonunion after IM nailing. These patients underwent reoperation with plate augmentation, exchange nailing, or combined treatment. Clinical and radiographic outcomes were assessed and compared according to reoperation procedure. Logistic regression analysis was performed to identify factors affecting persistent nonunion after reoperation. RESULTS: Of the cohort, 57 patients underwent plate augmentation, 64 underwent exchange nailing, and 28 received combined treatment. There were no significant differences in patient demographics among the groups. Exchange nailing produced a significantly lower union rate than did the combined treatment (82.8% vs. 100%, p = 0.016), whereas no significant difference was observed in the union rate and time to the union between plate augmentation and the combined treatment. Combined treatment showed the longest operative time and the greatest transfusion requirements. The risk factors for persistent nonunion included age, absence of autogenous bone grafts, and use of an exchange nailing technique. CONCLUSIONS: Exchange nailing as a treatment for atrophic femoral shaft nonunion after IM nailing resulted in a lower union rate. The efficacy of the combined treatment requires further study, and persistent nonunion may be influenced by age, bone grafting, and surgical techniques. A comprehensive approach targeting both biological environment and mechanical stability is crucial in the treatment of atrophic femoral shaft nonunion.

Critical size bone defects managed with modern techniques of bone transport: An update.

Bone transport is one of several techniques that has been proven to be effective in addressing critical bone loss. While it was first described over 100 years ago, modifications to this technique coupled with advances in technology have allowed us to perform bone transport with higher success rates and reduced complication rates. Modern techniques of bone transport aim to shorten the duration of time an external fixator is utilized to reduce its associated complications and burden to patients. We present an update on modern techniques of bone transport for critical size defects and methods to shorten the external fixation time.

Blocking screw (pin) technique to achieve an acceptable reduction in intramedullary of subtrochanteric femoral fractures: indications, techniques, and clinical outcomes.

INTRODUCTION: Subtrochanteric femur fractures treated with intramedullary nails present biomechanical benefits, early weight-bearing, and reduced soft tissue damage, promoting bone union. However, improper reduction due to muscular forces and fragmented proximal bone increases nonunion risk. This study evaluates the efficacy of the blocking screw technique in preventing malalignment during intramedullary nailing. MATERIAL AND METHODS: In cases of subtrochanteric femoral fractures where malalignment, such as varus and anterior angulation, was anticipated during intramedullary nailing, proper reduction was ensured using blocking screw technique on the proximal bone fragment from the coronal or sagittal plane. A retrospective analysis was conducted on 25 patients (14 males, 11 females; average age 55.12 years) who were followed up for more than 1 year. The postoperative neck-shaft angle, anterior angulation angle, and limb length discrepancy were compared radiologically with those on the healthy side, and the presence and duration of bone union were measured. The Harris hip score was used for functional evaluation, and complications, including infection, were analyzed. RESULTS: At the final follow-up, primary bone union was achieved in 21/25 patients (84%), with an average bone union time of 21.81 weeks (range, 14-42 weeks). Of the four nonunions, bone union was achieved in three cases through bone grafting and supplemental plating and in the other case through intramedullary exchange, supplemental plating, and bone grafting. The femoral neck-shaft angle and anterior angulation showed no statistically significant differences compared with the healthy side, with averages of - 1.15° and - 1.4°, respectively. The limb length discrepancy was an average of - 2.4 mm. Regarding functional outcomes, the Harris hip score averaged 89.52 points (range 82-94 points). CONCLUSIONS: In subtrochanteric femoral fractures, the blocking screw technique effectively prevents malalignment during intramedullary nailing, ensuring not only appropriate reduction but also high bone union rates.

Bioactive Bone Substitute in a Rabbit Ulna Model: Preclinical Study.

BACKGROUND: Current therapies to effectively treat long-bone defects and extensive bone tissue loss remains limited. In this study, we created a new bone substitute by integrating advanced technologies such as structure patterning, controlled release of a bone growth factor and conjugation system for clinically effective bone regeneration. This novel bioactive bone substitute was evaluated for its safety and efficacy using a rabbit ulna model. METHODS: A three dimensional bone patterned cylindrical structure with 1.5 cm in length and 5 mm in diameter was printed using poly(L-lactic acid)(PLLA) as a weight-bearing support and space-filling scaffold. And a bone morphogenetic protein 2 (BMP2) was employed to enhance bone regeneration, and coated to a 3D PLLA using alginate catechol and collagen to prolong the release kinetics. This novel bone substitute (BS)was evaluated for its physico-chemical and biological properties in vitro, and histological analysis and radiographical analysis such as X-ray, CT and micro-CT image analysis were performed to evaluate new bone formation in vivo. RESULTS: The BS possesses an ideal shape and mechanically suitable proeperties for clinical use, with an easy-to-grab and break-resistant design at both ends, 80 ± 10 MPa of compression strength, and BMP2 release for two months. Histological analysis demonstrated the biocompability of BS with minimal inflammation and immune response, and X-ray, CT and micro-CT demonstrated effective new bone formation in rabbit ulna defect model. CONCLUSION: The preclinical study of a novel bioactive bone substitute has shown its safe and effective properties in an animal model suggesting its clinical potential.

Current Management of Diaphyseal Long Bone Defects-A Multidisciplinary and International Perspective.

The treatment of defects of the long bones remains one of the biggest challenges in trauma and orthopedic surgery. The treatment path is usually very wearing for the patient, the patient's environment and the treating physician. The clinical or regional circumstances, the defect etiology and the patient´s condition and mental status define the treatment path chosen by the treating surgeon. Depending on the patient´s demands, the bony reconstruction has to be taken into consideration at a defect size of 2-3 cm, especially in the lower limbs. Below this defect size, acute shortening or bone grafting is usually preferred. A thorough assessment of the patient´s condition including comorbidities in a multidisciplinary manner and her or his personal demands must be taken into consideration. Several techniques are available to restore continuity of the long bone. In general, these techniques can be divided into repair techniques and reconstructive techniques. The aim of the repair techniques is anatomical restoration of the bone with differentiation of the cortex and marrow. Currently, classic, hybrid or all-internal distraction devices are technical options. However, they are all based on distraction osteogenesis. Reconstructive techniques restore long-bone continuity by replacing the defect zone with autologous bone, e.g., with a vascularized bone graft or with the technique described by Masquelet. Allografts for defect reconstruction in long bones might also be described as possible options. Due to limited access to allografts in many countries and the authors' opinion that allografts result in poorer outcomes, this review focuses on autologous techniques and gives an internationally aligned overview of the current concepts in repair or reconstruction techniques of segmental long-bone defects.

Reliability of reverse sural artery fasciocutaneous flap in older adult patients: Comparison study between older and younger patients.

BACKGROUND: The reverse sural artery fasciocutaneous (RSAF) flap is a popular option for patients with soft tissue defects of the distal lower extremities. However, most studies have focused on young patients without comorbidities. This study aimed to report the clinical application of the RSAF flap and to evaluate its reliability in older adult patients. METHODS: A retrospective study of fifty-one patients who underwent RSAF flap was included in this study between September 2016 and October 2021. Reconstruction outcomes and wound complications were compared between groups A (21 patients over 60 years of age) and B (30 patients under 60 years of age). RESULTS: Overall, 74.5% of the flaps healed primarily. The demographics of the two groups were similar, except for comorbidities (P = 0.01). The risk factors that affected the survival of RSAF flaps were not significantly different between the two groups (P > 0.05). The rate of wound complications in group A (42.85%) was significantly higher than that in group B (13.3%) (P = 0.04). However, all wound complications were treated using a simple procedure (skin grafting or simple suturing). CONCLUSIONS: The RSAF flap can be a reliable salvage option to repair soft tissue defects of the lower extremities in older adult patients. It is safe and easy to harvest and transfer the flap; however, surgeons should be aware of the possibility of wound complications in older patients with comorbidities.

Outcomes of Angular Stable Locking System in Femoral Diaphyseal Fractures of Elderly Patients: A Multicenter Comparative Study.

Background: The angular stable locking system (ASLS) was developed to provide additional stability to the distal interlocking screw of the intramedullary (IM) nail. Effects of ASLS on the treatment of femoral diaphyseal fractures in the elderly remain unknown. The aim of this study was to compare radiological outcomes of IM nailing using ASLS screws to IM nails with conventional interlocking screws in elderly patients with femoral shaft fractures. Methods: A multicenter retrospective review of 129 patients (average age, 73.5 years; 98 women and 31 men) aged 65 years or older who underwent IM nail fixation for femoral diaphyseal fractures (AO/Orthopaedic Trauma Association [OTA] classification 32) was conducted. Demographic information of patients, fracture site (subtrochanteric or shaft), fracture type (traumatic or atypical), and AO/OTA fracture classification were investigated. Reduction status was evaluated by postoperative plain radiography. Presence of union and time to union were evaluated through serial plain radiograph follow-up. Reoperation due to nonunion or implant failure was also evaluated. Results: ASLS was used in 65 patients (50.3%). A total of 118 patients (91.5%) achieved union without additional surgery and the mean union time was 31.8 ± 13.0 weeks. In terms of reduction status, angulation was greater in the group using ASLS. There were no statistically significant differences of union rate, time to union, and reoperation rate according to the use of ASLS (p > 0.05). There was no difference in the outcomes according to the use of ASLS even when the analysis was divided in terms of fracture site or fracture type (p > 0.05). In further subgroup analysis, only the traumatic subtrochanteric area group showed statistically significantly shorter time to union when ASLS was used (p = 0.038). Conclusions: In geriatric patients with femoral diaphyseal fractures, the use of ASLS was not considered to have a significant effect on fracture healing. Fracture healing seemed to be more affected by surgical techniques such as minimizing the gap and fracture characteristics such as atypical femoral fractures, rather than implants.

Radius palmar plate removal without carpal tunnel release: Correlation between plate position and median nerve symptoms.

We aimed to report the clinical results of volar plate removal without carpal tunnel release in patients with late-onset median neuropathy and to evaluate the relationship between plate position and median nerve symptoms. Part I. Twelve consecutive patients with late-onset median neuropathy treated with volar plate removal without carpal tunnel release were enrolled for analysis. Pre- and post-operative Tinel sign, Phalen and Ten test, subjective rating of tingling sensation, Mayo wrist score and Disabilities of the Arm, Shoulder and Hand (DASH) score were collected. Part II. 232 consecutive patients underwent volar plating for distal radius fracture. The relationships between median nerve symptoms and volar plate prominence on the Soong classification, fracture classification, gender and age were investigated. All cases except one showed complete symptom resolution at final follow-up, with negative Tinel sign and Ten test score of 10/10. Tingling was rated 0 at final follow-up. Mean Mayo wrist and DASH scores improved to 86.7 and 23.1, respectively. The incidence of the median nerve symptoms in our cohort was 5.6%. Even though the odds ratio in Soong grade 2 was 4.0957 (95% CI, 0.93-16.9) compared to the combination of grades 0 and 1, no statistically significant relationship was found between the median nerve symptoms and volar plate prominence (p > 0.05). Plate removal without carpal tunnel release adequately relieved symptoms of late-onset median neuropathy after volar plating in patients with distal radius fracture. LEVEL OF EVIDENCE: IV; Therapeutic.

Minimally Invasive Derotational Osteotomy of Long Bones: Smartphone Application Used to Improve the Accuracy of Correction.

Correction of rotational malalignments caused by fractures is essential as it may cause pain and gait disturbances. This study evaluated the intraoperative use of a smartphone application (SP app) to measure the extent of corrective rotation in patients treated using minimally invasive derotational osteotomy. Intraoperatively, two parallel 5 mm Schanz pins were placed above and below the fractured/injured site, and derotation was performed manually after percutaneous osteotomy. A protractor SP app was used intraoperatively to measure the angle between the two Schanz pins (angle-SP). Intramedullary nailing or minimally invasive plate osteosynthesis was performed after derotation, and computerized tomography (CT) scans were used to assess the angle of correction postoperatively (angle-CT). The accuracy of rotational correction was assessed by comparing angle-SP and angle-CT. The mean preoperative rotational difference observed was 22.1°, while the mean angle-SP and angle-CT were 21.6° and 21.3°, respectively. A significant positive correlation between angle-SP and angle-CT was observed, and 18 out of 19 patients exhibited complete healing within 17.7 weeks (1 patient exhibited nonunion). These findings suggest that using an SP app during minimally invasive derotational osteotomy can result in accurate correction of malrotation of long bones in a reproducible manner. Therefore, SP technology with integrated gyroscope function represents a suitable alternative for determination of the magnitude of rotational correction when performing corrective osteotomy.

Application of an Intraoperative Limb Positioner for Adjustable Traction in Both-Column Fractures of the Acetabulum: A Technical Note with Clinical Outcome.

Traction of the ipsilateral leg is usually required to facilitate fracture reduction while operating both-column acetabular fractures. However, it is challenging to maintain constant traction manually during the operation. Herein, we surgically treated such injuries while maintaining traction using an intraoperative limb positioner and investigated the outcomes. This study included 19 patients with both-column acetabular fractures. Surgery was performed after the patient's condition had stabilized, at an average of 10.4 days after injury. The Steinmann pin was transfixed to the distal femur and connected to a traction stirrup; subsequently, the construct was affixed to the limb positioner. A manual traction force was applied through the stirrup and maintained with the limb positioner. Using a modified Stoppa approach combined with the lateral window of the ilioinguinal approach, the fracture was reduced, and plates were applied. Primary union was achieved in all cases at an average of 17.3 weeks. The quality of reduction at the final follow-up was found to be excellent, good, and poor in 10, 8, and 1 patients, respectively. The average Merle d'Aubigné score at the final follow-up was 16.6. Surgical treatment of both-column acetabular fracture using intraoperative traction with a limb positioner yields satisfactory radiological and clinical outcomes.

Prophylactic Femoral Neck Fixation in an Osteoporosis Femur Model: A Novel Surgical Technique with Biomechanical Study.

Intramedullary nailing (IMN) is a popular treatment for elderly patients with femoral shaft fractures. Recently, prophylactic neck fixation has been increasingly used to prevent proximal femoral fractures during IMN. Therefore, this study aimed to investigate the biomechanical strength of prophylactic neck fixation in osteoporotic femoral fractures. An osteoporotic femur model was created to simulate the union of femoral shaft fractures with IMN. Two study groups comprising six specimens each were created for IMN with two standard proximal locking screws (SN group) and IMN with two reconstruction proximal locking screws (RN group). Axial loading was conducted to measure the stiffness, load-to-failure, and failure modes. There were no statistically significant differences in stiffness between the two groups. However, the load-to-failure in the RN group was significantly higher than that in the SN group (p < 0.05). Femoral neck fractures occurred in all specimens in the SN group. Five constructs in the RN group showed subtrochanteric fractures without femoral neck fractures. However, one construct was observed in both subtrochanteric and femoral neck fractures. Therefore, prophylactic neck fixation may be considered an alternative biomechanical solution to prevent proximal femoral fractures when performing IMN for osteoporotic femoral fractures.

The role of an augmentative plating in the management of femoral subtrochanteric nonunion.

INTRODUCTION: Owing to its distinct biomechanical properties, nonunion is common (7-20%) after intramedullary (IM) nailing of subtrochanteric femoral fractures. Unlike diaphyseal nonunion, it is difficult to provide sufficient stability by exchanging nailing alone in subtrochanteric nonunion. This study investigated the clinical outcomes of femoral subtrochanteric nonunion initially treated with an IM nail and subsequently managed with minimally invasive augmentative plate fixation. MATERIALS AND METHODS: Nineteen patients were enrolled retrospectively. The mechanisms of initial injury were traffic accidents in 8, falls from a height in seven, and slipping in two patients. Two patients with atypical subtrochanteric femoral fractures without a specific trauma history were further included. All patients underwent IM nailing as the index operation. Nonunion surgery was performed an average of 45.2 weeks after the initial surgery. In cases of hardware damage and/or atrophic nonunion, exchange nailing and bone grafting were performed in addition to augmentative plating, as necessary. Conversely, augmentative plating alone was performed in cases of hypertrophic nonunion without any failure of the preexisting IM nail or malalignment. A narrow locking compression plate was fixed after contouring according to the shape of the proximal femur. The mean follow-up period was 36.1 months. RESULTS: Bony union was achieved in 18/19 patients (94.7%), at an average of 19.8 weeks after nonunion surgery. In the case that did not heal even after exchange nailing, additional plating and bone grafting, further autogenous bone grafting was required after 11 months, which healed uneventfully. There were 2 cases of soft tissue irritation over the plate, but no major complications were observed. CONCLUSIONS: Additional plate augmentation over a retained IM nail yields satisfactory outcomes in terms of the bony union in subtrochanteric nonunion. Given its expected biomechanical superiority and relatively easy surgical technique, it may be a reasonable option for the management of femoral subtrochanteric nonunion.

Structure-mechanical analysis of various fixation constructs for basicervical fractures of the proximal femur and clinical implications; finite element analysis.

OBJECTIVE: This present study was conducted to determine the structural-mechanical stability of various fixation constructs through finite element (FE) analysis following simulation of a basicervical fracture and to introduce the clinical implications. MATERIALS AND METHODS: We simulated fracture models by using a right synthetic femur (SAWBONES®). We imported the implant models into ANSYS® for placement in an optimal position. Five assembly models were constructed: (1) multiple cancellous screws (MCS), (2) FNS (femoral neck system®), (3) dynamic hip screw (DHS), (4) DHS with anti-rotation 7.0 screw (DHS + screw), and PFNA-II (Proximal Femoral Nail Antirotation-II®). The femur model's distal end was completely fixed and 7° abducted. We set the force vector at a 3° angle laterally and 15° posteriorly from the vertical ground. Analysis was done using Ansys® software with von Mises stress (VMS) in megapascals (MPa) and displacement (mm) RESULTS: The displacements of the proximal femur were 10.25 mm for MCS, 9.66 mm for DHS, 9.44 mm for DHS + screw, 9.86 mm for FNS, and 9.31 mm for PFNA-II. The maximum implant VMS was 148.94 MPa for MCS, 414.66 MPa for DHS, 385.59 MPa for DSH + screw, 464.07 MPa for FNS, and 505.07 MPa for PFNA-II. The maximum VMS at the fracture site was 621.13 MPa for MCS, 464.14 MPa for DHS, 64.51 MPa for DHS + screw, 344.54 MPa for FNS, and 647.49 MPa for PFNA-II. The maximum VMS at the fracture site was in the superior area with the high point around the posterior screw in the MCS, anterosuperior corner in the DHS, the posteroinferior site of the FNS, and posterosuperior site around the entry point in the PFNA-II. In the DHS + screw, the stresses were distributed evenly and disappeared at the maximum VMS fracture site. CONCLUSION: Based on the fracture site and implant's stress distribution, the model receiving the optimal load was a DHS + screw construct, and the FNS implant could be applied to anatomically reduced fractures without comminution. Considering the high-stress concentration around the entry point, a PFNA-II fixation has a high probability of head-neck fragment rotational instability.

rhBMP-2-Conjugated Three-Dimensional-Printed Poly(L-lactide) Scaffold is an Effective Bone Substitute.

BACKGROUND: Bone growth factors, particularly bone morphogenic protein-2 (BMP-2), are required for effective treatment of significant bone loss. Despite the extensive development of bone substitutes, much remains to be desired for wider application in clinical settings. The currently available bone substitutes cannot sustain prolonged BMP-2 release and are inconvenient to use. In this study, we developed a ready-to-use bone substitute by sequential conjugation of BMP to a three-dimensional (3D) poly(L-lactide) (PLLA) scaffold using novel molecular adhesive materials that reduced the operation time and sustained prolonged BMP release. METHODS: A 3D PLLA scaffold was printed and BMP-2 was conjugated with alginate-catechol and collagen. PLLA scaffolds were conjugated with different concentrations of BMP-2 and evaluated for bone regeneration in vitro and in vivo using a mouse calvarial model. The BMP-2 release kinetics were analyzed using ELISA. Histological analysis and micro-CT image analysis were performed to evaluate new bone formation. RESULTS: The 3D structure of the PLLA scaffold had a pore size of 400 µm and grid thickness of 187-230 µm. BMP-2 was released in an initial burst, followed by a sustained release for 14 days. Released BMP-2 maintained osteoinductivity in vitro and in vivo. Micro-computed tomography and histological findings demonstrate that the PLLA scaffold conjugated with 2 µg/ml of BMP-2 induced optimal bone regeneration. CONCLUSION: The 3D-printed PLLA scaffold conjugated with BMP-2 enhanced bone regeneration, demonstrating its potential as a novel bone substitute.

Clinical outcomes and affecting factors of ipsilateral femoral neck and shaft fractures - Multination, multicenter analysis.

BACKGROUND: This study aimed to evaluate the clinical outcomes of ipsilateral femoral neck and shaft fractures and identify the risk factors associated with missed diagnosis of femoral neck fractures and clinical outcomes of this fracture. METHODS: The ipsilateral femoral neck and shaft fractures from seven centers were retrospectively reviewed. Data on injury mechanism, fracture pattern, and fracture classification; surgical factors including fixation method; and timing of detection of femoral neck fracture were analyzed. The clinical outcomes, complications, and the incidence of avascular necrosis of the femoral head (AVNFH) were reviewed. Risk factors for missed femoral neck fracture and complications were analyzed. RESULTS: In total, 74 patients with an average age of 43.6 years were included. Of the femoral shaft fractures, 56.8% were type A, 21.6% were type B, and 21.6% were type C. Sixteen patients had an open fracture of the femoral shaft. Femoral neck fracture was initially missed in 27% patients and the timing of delayed diagnosis was at an average of 11.1 days after injury. For detecting femoral neck fractures, minimal displacement of the femoral neck fracture was a risk factor, whereas computed tomography (CT) was a protective factor. The incidence of AVNFH was 6.8% at an average of 36.8 months after injury. The AVNFH group had more displaced femoral neck fractures at the time of surgery, but there was no difference in the timing of diagnosis compared to non-AVNFH group. The femoral shaft showed considerable healing problems, with an average union time of 29.7 weeks and a 20.2% nonunion rate. CONCLUSION: Ipsilateral femoral neck and shaft fractures had a high rate of missed diagnosis, especially in minimally displaced fractures; however, CT was a protective factor. AVNFH occurred in 6.8% and was related to femoral neck fracture displacement, but not delayed diagnosis. The femur nonunion rate was high, which warrants attention.

Acetabular fractures in elderly.

BACKGROUND: This study aimed to determine characteristics of acetabular fractures in the elderly by evaluating clinical course and computed tomography-based radiological features between low- and high-energy acetabular fractures. METHODS: We reviewed 178 consecutive patients with acetabular fractures aged ≥60 years from six centers. Low-energy fractures (group 1) were identified in 23 (12.9%) patients and high-energy fractures (group 2) in 155 (87.1%) patients. We compared demographics, radiological findings, and clinical course between the groups. RESULTS: Average age (70.6 vs. 67.8 years, p = 0.046) and ratio of females (47.8% vs. 23.2%, p = 0.021) were significantly higher in group 1 than in group 2. The Charlson comorbidity index was also higher in group 1, but no other demographics showed difference. More patients in group 2 than in group 1 underwent surgery (91.6% vs. 73.9%); however, more in group 1 underwent minimally invasive surgery (17.4% vs 4.5%). Anterior column-associated fracture patterns occurred in 91.4% and 38.7% of cases in groups 1 and 2, respectively. Most fractures were displaced (>2 mm); 68% of which were comminuted. Furthermore, 24.2% of the fractures had superior dome impaction, whereas 23.0% were associated with posterior wall impaction. CONCLUSIONS: Patients who sustained low-energy acetabular fractures were mostly women, were older, and had more comorbidities. Radiological findings of low-energy acetabular fractures showed anterior column involvement associated with injury to the quadrilateral surface. Additionally, it was observed to be commonly combined with comminution and impacted fragments.

Incomplete Diaphyseal Atypical Femoral Fracture due to Increased Anterolateral Bowing: Treatment with Corrective Osteotomy and Intramedullary Nailing with Augmented Plate Fixation.

BACKGROUND: Increased anterolateral bowing of the femur is associated with atypical femoral fractures among older patients (including both those receiving and those not receiving treatment with bisphosphonates) as well as a greater likelihood of occurring in the diaphyseal versus the subtrochanteric region. Prophylactic intramedullary (IM) nailing is recommended for the treatment of incomplete atypical femoral fractures, which are radiographically evident. However, this bowing deformity is considered to be a major obstacle to IM nailing as it may be associated with postoperative complications. Corrective osteotomy combined with IM nailing straightens the exaggerated curvature of the femur. We hypothesized that this technique may lead to the safe and rapid healing of incomplete diaphyseal atypical femoral fractures, thereby reducing lateral tensile stress. METHODS: From October 2015 through March 2020, 17 female patients (20 femora) with a mean age of 76.1 years (range, 68 to 86 years) underwent a surgical procedure for the treatment of an incomplete diaphyseal atypical femoral fracture associated with anterolateral bowing. The surgical technique consisted of minimally invasive osteotomy and reconstruction with use of IM nailing, with or without an augmentation plate. Preoperative and postoperative radiographic findings (lateral and anterior bowing angles, anterolateral bowing grade, and lateral distal femoral angle [LDFA]) were compared. Primary union, time to union, and complications were evaluated as the outcomes. RESULTS: Primary bone union was achieved in 19 of the 20 femora at a mean of 24.9 weeks (range, 20 to 40 weeks). There were 2 instances of delayed union, which healed at 36 and 40 weeks. The lateral bowing angle, anterior bowing angle, and LDFA significantly improved postoperatively (from 12.0° to 3.3°, from 17.3° to 11.5°, and from 93.5° to 88.8°, respectively) (p < 0.001). There was 1 instance of nonunion, which healed after plate augmentation without a bone graft. CONCLUSIONS: Given the pathophysiology of elevated lateral tensile stress, corrective osteotomy and IM nailing may be an acceptable solution for the treatment of incomplete diaphyseal atypical femoral fractures associated with increased anterolateral bowing. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.