Bone and soft tissue reconstruction with tendon balance in severe foot trauma.

In severe foot trauma, it is difficult to determine the level of amputation when the crush injury is severe. We report a case of amputation near Lisfranc that achieved forefoot amputation-like results by using bone and soft tissue reconstruction while considering tendon balance. The patient was a 40-year-old male. The patient's left leg was caught in a garbage truck and sustained a crush injury. The second to fifth metatarsals were amputated at the diaphysis, and a high degree of instability of the Lisfranc joint was observed. A high degree of contamination was detected in the patient's wound, and the second to fifth toes were amputated at the Lisfranc joint during the initial treatment. The ends of the tibialis anterior, tibialis posterior and peroneus longus were preserved. On day 5 in the hospital, Lisfranc joint fixation of the hallux, amputation of the first metatarsal and reconstruction of the peroneus brevis were performed. On day 13, extensor hallucis longus tendon transfer and free anterolateral thigh flap were performed. On day 80, the patient was able to walk in regular shoes or non-orthopedic shoes. One year after reconstructive surgery, the patient had an average SAFE-Q score of 86.2 and mild varus deformity of the foot remained. In cases of severe foot trauma, the aim of reconstruction should be partial forefoot amputation whenever possible.

Efficacy of Orthoplastic Management in the Treatment of Traumatic Popliteal Artery Injury.

Background: Popliteal artery injury (PAI) is a challenging condition. Even with appropriate initial treatment and reconstruction of the associated injuries, extensive soft-tissue necrosis may occur, requiring lower leg amputation. There are no reports on the effectiveness of orthoplastic surgery in treating traumatic PAI. However, orthoplastic surgery is also considered very effective in PAI treatment, which requires delicate handling of soft-tissue and blood vessels. This study aimed to examine the treatment outcomes of traumatic PAI at a trauma center with the capacity for orthoplastic management. Methods: Patients with PAI who were treated at our institution between August 2013 and December 2021 were included in this study. The surgeons included multiple orthoplastic surgeons with capabilities in vascular repair, bone and ligament reconstruction, and soft-tissue reconstruction. Patient demographics, injury characteristics, degree of ischemia, and treatment were investigated. We also investigated whether soft-tissue reconstruction and lower limb amputation were necessary as outcomes of treatment. Results: Fifteen limbs of 14 patients with PAI met the inclusion criteria. Extensive soft-tissue necrosis was observed in three limbs. Two of these limbs were covered with a free latissimus dorsi flap and could be salvaged. In the remaining limb, lower limb amputation was unavoidable because of unexplained cardiac arrest during the initial surgery, but a fillet flap was used to successfully preserve the knee joint. Conclusion: Orthoplastic management has the potential to improve limb salvage rates and provide good outcomes for the treatment of traumatic PAI.

Cross-Limb Vascular Shunting for Traumatic Popliteal Artery Injury.

BACKGROUND: Popliteal artery injury (PAI) is a challenging trauma that requires prompt and accurate treatment since the probability of lower-limb amputation increases with the ischemic time. Intravascular shunting and cross-limb vascular shunting (CLS) are used as temporary vascular shunting (TVS) methods to shorten the ischemic time for limb vascular injury. CLS involves sending blood from an artery in a healthy body part to a peripheral vessel in an injured part to immediately resume blood flow to the injured limb. For closed injuries including PAI, CLS may be performed without exploring and identifying the arterial stumps and it enables early reperfusion to the ischemic limb. We report the case series of traumatic PAI treated using CLS and verify the usefulness of CLS. METHODS: All patients with traumatic PAI treated with CLS at our institution between August 2013 and December 2021 were included. Demographic and clinical patient characteristics were extracted from the medical records. Comorbid injuries, severity of acute limb ischemia based on the Rutherford grading scale, time from injury to reperfusion by CLS, time from injury to completion of artery, and the use of fasciotomy were investigated. As outcomes, we investigated the presence or absence of lower extremity amputation during the course of treatment. RESULTS: We used CLS as treatment for 5 cases with traumatic PAI. Based on the Rutherford grading scale for acute limb ischemia, there were one limb with grade 2B and 4 with grade 3. Amputation of the lower extremities was avoided except for 1 extremity in which arterial reconstruction was not achieved due to unexplained cardiac arrest during surgery. CONCLUSIONS: CLS enables early reperfusion of the injured limb and is effective as a TVS method for traumatic PAI with severe ischemia or soft tissue damage.

Surgical delay in reverse sural artery flap prevents congestion of the flap: a case report of the stepwise delay method.

We performed reverse sural artery flap (RSAF) with the stepwise delay method, cutting the vascular pedicle step by step, as the patient had a high risk of flap necrosis. Surgical delay in RSAF is anticipated to prevent not only flap cyanosis but also flap congestion.

Management of bone loss in acute severe open tibial fractures: a retrospective study of twenty nine cases-a treatment strategy with bone length preservation.

PURPOSE: The present study investigated the outcomes of bone loss associated with acute open tibial fractures classified as Gustilo-Anderson classification grade III B (GIIIB) using a bone length preservation strategy. METHODS: Among acute GIIIB open tibial fractures, 29 limbs of 29 patients requiring bone loss treatment were included. The reconstruction methods for bone loss were selected among the Masquelet technique (MT), bone transport (BT), acute shortening followed by gradual lengthening (ASGL), and free vascularized fibula graft (FVFG). Primary outcome measures were the rate of bone union and time to bone union. RESULTS: The median radiographic apparent bone gap (RABG) was 46.75 mm. Bone loss was treated with ASGL only in two patients in whom it was not possible to cover large soft tissue defects by a single free latissimus dorsi (LD) myocutaneous flap (with the serratus anterior (SA) muscle). The other 27 patients underwent soft tissue reconstruction and bone loss treatment with the preservation of bone length, including the MT for 23, BT for six, and FVFG for one. The bone union rate was 75.9%, and the median time to bone union was six months. Salvage surgeries were performed on all seven patients with nonunion; all of whom eventually achieved bony union. CONCLUSION: Bone loss associated with acute GIIIB open tibial fractures were treated with "bone length preservation" if the size of the soft tissue defect was less than the size that was covered by a single LD myocutaneous flap (with the SA muscle).

Risk factors for over-telescoping in reverse oblique intertrochanteric fractures.

PURPOSE: Postoperative over-telescoping (OT) with lag screws is often observed in reverse oblique intertrochanteric fractures. This study aimed to clarify the risk factors of OT in patients with reverse oblique intertrochanteric fractures. METHODS: Electronic medical records of patients diagnosed with reverse oblique intertrochanteric fractures using plain radiography who underwent operative fixation with an intramedullary nail between August 2013 and December 2019 were reviewed. Patients were classified into two groups according to the Futamura classification: lateral wall pattern (LW) and reverse oblique pattern (RO). The incidence of OT in the LW and RO groups was compared. Also, we compared the incidence of OT for each reduction type in the LW group. RESULTS: Twenty patients had LW, and nine had RO. OT was observed in eight fractures (42.1%) in the LW group but not in the RO group. The incidence of OT was significantly higher in the LW group than in the RO group (P = 0.0261). Among the 19 fractures with LW, OT was observed in 7 of 10 and 1 of 9 fractures with postoperative reduction in the intramedullary and extramedullary or anatomical types, respectively. In the LW group, the incidence of OT was significantly higher in fractures with postoperative reduction in the intramedullary type than in those of the extramedullary or anatomical type (P = 0.0198). CONCLUSION: Our study showed that the incidence of OT was significantly higher in LW than in RO and that postoperative reduction in the intramedullary type in LW was a risk factor for OT.

One incision-two windows approach for fixation of multifragmentary coronoid process fracture of the ulna: A case report.

Since the range of access of each surgical approach around the elbow has limitations, it is difficult to treat all types of fractures using only one approach. In the case reported herein, anterior and medial fragments of the comminuted ulnar coronoid process fracture were treated by preparing two access routes through one skin incision and effectively performing the buttress plating of each fragment. The subject was a 27-year-old female who sustained a fracture of the coronoid process of the right ulna by falling during snowboarding. Computed tomography showed the concurrence of a type 2 subtype III and type 3 subtype I ulnar coronoid process fracture according to the O'Driscoll classification. The coronoid process was split into 3 parts: a fragment consisting of the anteromedial facet and upper half of the sublime tubercle (fragment 1), a central fragment including the tip (fragment 2), and a fragment extending from the radial side of the tip to the base of the coronoid process (fragment 3). A 12-cm-long skin incision was made on the anteromedial side of the elbow joint. The region of the anteromedial facet and sublime tubercle was reached by passage between the palmaris longus/flexor digitorum superficialis and humeral head of flexor carpi ulnaris using the over-the-top approach. Fragment 1 was fixed with a buttress plate. Using the anterior approach, the brachialis was then longitudinally split through by passage between the biceps and neurovascular bundle, fragments 2 and 3 were fixed together with a buttress plate. The "one incision-two windows" approach, which provides two approaches (the over-the-top window and the anterior window) by a single skin incision, was implemented for a multifragmentary ulnar coronoid process fracture. This approach is considered to offer access from the front to each of the anterior and medial fragments and permits appropriate buttress plate fixation.

Pull-in suture: a novel reconstruction technique for tendon avulsion injury at the musculotendinous junction associated with forearm open fracture.

We present three cases of strong one-staged tendon reconstruction for musculotendinous junction avulsion tendon injuries, and called it a 'pull-in suture'. The clinical outcomes of this method are comparable to those of tendon transfer; it is an effective reconstruction method that should be considered as an initial treatment procedure.

A novel technique for stabilising sacroiliac joint dislocation using spinal instrumentation: technical notes and clinical outcomes.

PURPOSE: Currently, sacroiliac joint dislocations, including crescent fracture-dislocations, are treated using several techniques that have certain issues. We present the technical details and clinical outcomes of a new technique, anterior sacroiliac stabilisation (ASIS), performed using spinal instrumentation. METHODS: ASIS is performed with the patient in a supine position via the ilioinguinal approach. The displacements are reduced and fixed by inserting cancellous screws from the sacral ala and iliac brim; the screw heads are bridged using a rod and locked. We performed a retrospective review of patients with iliosacral disruption who underwent ASIS between May 2012 and December 2020 at two medical facilities. The patients were assessed for age, sex, injury type, associated injuries, complications, functional outcome by evaluating the Majeed pelvic score after excluding the sexual intercourse score and fracture union. RESULTS: We enrolled 11 patients (median age: 63 years). The median operative time was 195 min, median blood loss was 570 g, and eight patients (72.3%) required blood transfusion. The sacral and iliac screws had a diameter of 6.0-8.0 mm and 6.2-8.0 mm, and a length of 50-70 mm and 40-80 mm, respectively. Bone union was achieved with no marked loss of reduction in the median follow-up period of 12 months in all cases. The median Majeed score at the final follow-up was 85/96. CONCLUSION: ASIS is a rigid internal fixation method that provides angular stability. Despite invasiveness issues compared to iliosacral screw fixation, this method is easy to confirm and achieves precise reduction.

Plate coverage predicts failure for volarly unstable distal radius fractures with volar lunate facet fragments.

INTRODUCTION: Loss of reduction after operative fixation of volarly unstable distal radius fractures with a volar lunate facet fragment (VLF) is considered problematic because it results in carpal subluxation or dislocation and subsequent impaired function. We hypothesized that the indicator of loss of reduction of the VLF after fixation is plate coverage of the bony fragment. We investigated the relationship between the plate coverage of the VLF and loss of reduction after fixation, and calculated the plate coverage that was associated with failure of fixation of the VLF. MATERIALS AND METHODS: We conducted a retrospective review. We included patients with surgically treated volarly unstable distal radius fractures with VLF with a volar locking plate who had a minimum follow-up of 6 months. A total of 33 patients (35 wrists) met criteria for inclusion into the study. The patients were divided into a displacement group and a non-displacement group. We calculated and compared longitudinal dimension and plate coverage of the VLF between the two groups to reveal the risk factors for loss of reduction. RESULTS: At final follow-up, 25 fractures maintained radiographic alignment and 10 (28.6%) lost reduction. Univariate analysis between the two groups showed that plate coverage against the transverse and longitudinal dimension of the VLF was correlated with loss of reduction after operative fixation. In multivariate logistic regression analysis, only plate coverage against the longitudinal dimension of the VLF remained a significant predictor of failure. With 64.7% as the cut-off point for plate coverage against the longitudinal dimension of the VLF, the sensitivity and specificity of the prediction were 96% and 80%, respectively. CONCLUSION: The predictor of loss of reduction after fixation of volarly unstable distal radius fractures with a VLF was plate coverage against the longitudinal dimension of the VLF.

Time-Dependent Magnetic Resonance Imaging Changes in Occult Femoral Neck Fracture During Conservative Treatment: A Case Report.

CASE: A 53-year-old woman presented to the emergency department with persistent left hip pain after a fall while riding a bicycle. Although x-ray imaging revealed no evidence of fracture, an abnormal intensity vertical line along the left femoral neck was observed in the magnetic resonance imaging (MRI). Furthermore, 2 weeks after injury, MRI revealed a newly developed abnormal intensity oblique band at the femoral neck. After discussing several treatment options with the patients, she chose the conservative treatment. CONCLUSION: Careful follow-ups and MRI were undertaken 6 times within 32 weeks. Bone union was observed 32 weeks after the injury, and no bone displacement was observed.

Fracture dislocation of the ankle with posterior tibial tendon entrapment within the tibiofibular interosseous space: A case report.

In rare cases of ankle fracture dislocation, the posterior tibial muscle tendon (TP tendon) is incarcerated between the tibia and fibula, thereby impeding reduction. Here we describe a case that presented with such a condition, in which ankle reduction was achieved and surgical repair of the incarcerated TP was delayed. The subject was a 30-year-old male who sustained a fracture dislocation of the left ankle (AO:44-C1.3) in a motorbike accident. After repairing the ankle dislocation, external fixation was performed and osteosynthesis was conducted 10 days after the injury. Plate fixation for the fibula fracture and tight rope fixation for the separation between the tibia and fibula were performed; however, internal fixation for the medial malleolus fracture was delayed because the skin on the medial side of the ankle was in poor condition. One month after the injury, osteosynthesis of the medial malleolus was performed, and the TP tendon was identified in the fracture site. After removing the incarcerated tendon, good reduction of the medial malleolus was achieved, and thus, internal fixation and wound closure could be performed. Re-examination revealed that the TP tendon had an abnormal course. After 3 months, upon re-exposing the entire length of the TP tendon, the TP tendon was incarcerated between the tibia and fibula. To date, although several cases have been reported regarding TP tendon incarceration caused by fracture dislocation of the ankle, no study has reported the anatomical repair of the ankle, regardless of tendon incarceration. In our case, rotational displacement of the medial malleolus fracture remained when the second surgery was completed; however, the presence of some type of incarcerated tissue was suspected. Because leaving the incarcerated TP tendon untreated can cause irreversible long-term complications, early anatomical repair is recommended.

"Within ring"-based sacroiliac rod fixation may overcome the weakness of spinopelvic fixation for unstable pelvic ring injuries: technical notes and clinical outcomes.

PURPOSE: Spinopelvic fixation and triangular osteosynthesis give firm internal fixation for unstable pelvic ring injuries (UPRI), but with sacrifice of mobility of the lumbar spine. Here, we describe the procedure and outcomes of a new approach, which we refer to as "within ring"-based sacroiliac rod fixation (SIRF). METHODS: The patient was placed in a prone position and longitudinal skin incisions were made at the medial margins of the bilateral posterior superior iliac spines (PSIS). After reduction of fracture, a pedicle screw was inserted into the first sacral vertebra on the injured side and iliac screws inserted through the bilateral PSIS were bridged using rods. RESULTS: SIRF was performed in 15 patients. The AO/OTA classification was 61-B2.3 in 1, C1.3 in 4, C2.3 in 7, C3.3 in 1, and H-type spinopelvic dissociation in two cases. The mean operative time was 179 (110-298) minutes, mean blood loss was 533 (100-2700) cc. One patient died during hospitalization and three patients stopped outpatient treatment. The other 11 patients achieved bone union without major loss of reduction in a mean post-operative follow-up period of 23.8 (4-50) months. The mean Majeed score at final follow-up was 86.7 (73-96) out of 96, excluding scoring sexual intercourse. CONCLUSIONS: "Within ring"-based SIRF not including the lumbar spine in the fixation range is a simple, safe, and low-invasive internal fixation method for UPRI.

A biomechanical study of sacroiliac rod fixation for unstable pelvic ring injuries: verification of the "within ring" concept.

PURPOSE: The aim of this study was to compare the fixation power of sacroiliac rod fixation (SIRF), which was developed based on our original "within ring" concept to exclude the lumbar vertebra from the fixation range, and spinopelvic fixation (SPF) in a biomechanical experiment. METHODS: SPF and SIRF were applied to the posterior element in four bones each with the pelvic ring fracture model (AO/OTA classification 61-C1.3). A 300-N axial force was loaded on the fifth lumbar vertebra of the simulated pelvis. Then the stiffness (N/m) and deformation (mm) of SPF and SIRF were determined, and the final displacement (mm) of the fracture region and angular deformity (degrees) were measured. Displacements were measured using the markers at two sites of the sacral fracture [upper margin of the sacral ala (Ala) and second sacral vertebra level (S2)] and one site of the pubic symphysis (PS), and angular deformity was measured at Ala and PS. RESULTS: In SPF and SIRF, the mean stiffnesses and deformations showed no statistically significant difference. Only the vertical displacement at Ala differed significantly between SPF and SIRF (p = 0. 045), and the fixing force of SPF was higher. There was no other significant difference in vertical and horizontal displacement. The mean angular deformities also showed no significant difference between the two methods. CONCLUSIONS: In biomechanics experiments, vertical resistance was stronger in SPF-treated than SIRF-treated bone, but stiffness and deformation, horizontal resistance, and angular deformity did not differ significantly.

Difficulty in Fixation of the Volar Lunate Facet Fragment in Distal Radius Fracture.

Recent reports suggest the presence of a rare fracture type for which reduction and fixation cannot be achieved with volar locking plate (VLP). In particular, it is difficult to achieve reduction and fixation with volar lunate facet (VLF) fragments present on the volar ulnar aspect of the lunate facet, because of the anatomical structure and biomechanics in this region. Herein, we report two challenging cases of difficulty in fixation of the VLF fragment in distal radius fracture. For this fracture type, it is most important to identify the volar ulnar bone fragment before surgery; it may also be necessary to optimize distal placement of the VLP via a dual-window approach and to apply additional fixations, such as a small plate, anchor, and/or external fixation.

Malreduction of syndesmosis injury associated with malleolar ankle fracture can be avoided using Weber's three indexes in the mortise view.

PURPOSE: Malalignment of syndesmosis is generally associated with a poor outcome, yet occurs at a high rate in malleolar ankle fractures. In this study, we examine whether malreduction of syndesmosis injury associated with malleolar ankle fracture can be avoided using Weber's three indexes in the mortise view. MATERIALS AND METHODS: Of 156 patients with malleolar ankle fracture who underwent surgery from December 2012 to March 2016 at two medical facilities, 24 patients who received syndesmotic screw fixation were included in the study. Fractures were Danis-Weber types B and C in 8 (8/134, 6.0%) and 16 (16/22, 72.7%) patients, respectively. Using axial computed tomography (CT), we calculated the difference between injured and non-injured sides for each of three parameters: tibiofibular clear space (TFCS), anterior tibiofibular interval (ATF), and fibular rotation (θfib). Malreduction was diagnosed if one or more of the three parameters had an abnormal value. Weber's three indexes in the mortise view on the injured side were used to determine whether reduction of syndesmosis was performed successfully. Consistency between the evaluation of reduction of syndesmosis in axial CT images and reevaluation of mortise views was examined by calculation of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). RESULTS: The rate of malreduction of syndesmosis in axial CT images was 29.2% (7/24). Re-evaluation in the mortise view confirmed malreduction of syndesmosis in six of the seven subjects, all of whom also had malreduction based on axial CT images. The one subject in whom malreduction could not be detected in a mortise view showed an abnormal value only for ATF. Use of the mortise view for perioperative diagnosis had a sensitivity of 0.857, specificity of 1.000, PPV of 1.000, and NPV of 0.944. CONCLUSION: The results of our study show that malreduction of syndesmosis can be avoided by careful interpretation of intraoperative perspective mortise views based on Weber's three indexes. To increase the diagnostic accuracy further, it is important to detect anteroposterior deviation of the fibula in intraoperative lateral views.

New classification focusing on the relationship between the attachment of the iliofemoral ligament and the course of the fracture line for intertrochanteric fractures.

PURPOSE: There are various types of intertrochanteric fractures that are unstable pertrochanteric fractures of the hip. The aim of this study was to develop a systematic and comprehensive classification of intertrochanteric fractures. MATERIALS AND METHODS: This study enrolled 74 patients with intertrochanteric fractures treated by us between 2012 and 2015. The fractures were classified using 3D-CT images taken immediately after the fractures occurred based on the course of the lateral fracture line (LFL) that extends through the lateral femoral cortex distal to the vastus ridge of the greater trochanter in the intertrochanteric area. Furthermore, the presence or absence of additional typical fractures was also studied. Then, 4 orthopedic specialists examined the 3D-CT images of 20 patients randomly selected from the 74 patients to evaluate both the inter-rater and intra-rater agreement levels. RESULTS: Intertrochanteric fractures were classified into three types according to the LFL patterns. Type I (41.9%), the Lateral Wall Pattern, has a LFL that extends towards the lateral fiber bundle attachment area of the iliofemoral ligament. Type II (24.3%), the Transverse Pattern, has a LFL that extends towards the medial bundle attachment area. Type III (33.8%), the Reverse Oblique Pattern, has a LFL that extends between the lateral and medial fiber bundle area of the iliofemoral ligament. Each type showed characteristic displacement and was associated with various combinations of typical fractures (fracture across the intertrochanteric line, posteromedial fragment, including the lesser trochanter, posterolateral fragment posterior to the femoral greater trochanter, and banana-shaped big fragment, including both the greater trochanter and the lesser trochanter). The mean κ values for the interobserver and intraobserver agreement levels were 0.77 (0.70-0.85) and 0.76 (0.70-0.85), respectively, which were considered substantial agreement levels. CONCLUSION: We believe our new classification is a useful communication tool for medical professionals in the diagnosis of fractures.

New classification focusing on implant designs useful for setting therapeutic strategy for periprosthetic femoral fractures.

PURPOSE: In periprosthetic femoral fractures, our hypothesis was that when the bone and implant are stable, the fracture does not occur at the biologic or cement fixation regions but occurs at the no fixation region. The aim of this study was to investigate the validity of our new classification for periprosthetic femoral fractures and compare reliability of radiographic evaluation for implant stability between our classification and the Vancouver classification. PATIENTS AND METHODS: Sixty-six patients with periprosthetic femoral fracture were operatively treated by us between 2005 and 2013. We investigated the sensitivity and specificity of our new classification with actual implant stability. Twenty patients were randomly selected from 66 patients. After fully explaining the Vancouver and our new classification to four orthopaedic surgeons, plain radiographs acquired in two directions at the time of injury were presented, and the interobserver reliability based on the two classifications and accuracy rates of stem stability were investigated. RESULTS: The specificity of the new classification was 89%, and sensitivity was 94%. The positive and negative predictive values were 84% and 96%, respectively. Interobserver agreement was separately assessed among all possible pairs of orthopaedic surgeons. The κ values for the Vancouver and the new classification were 0.36 (0.19-0.49) and 0.76 (0.66-1.0), respectively. CONCLUSIONS: Our classification is based on a completely new concept and was prepared to overcome periprosthetic femoral fracture failures by objective evaluation. We believe this new classification is useful to establish a therapeutic strategy for femoral fractures around the stem.

Comparison of therapeutic outcomes of periprosthetic femoral fracture between treatments employing locking and conventional plates.

INTRODUCTION: Locking plate is considered biomechanically advantageous for porotic bone, compared with conventional plate. However, clinical evaluations of locking and conventional plates for periprosthetic femoral fracture are still controversial. Thus, we investigated the usefulness of a locking plate compared with the conventional plate for treatment for this fracture. MATERIALS AND METHODS: We reviewed 40 patients (40 fractures) who had undergone internal fixation for Vancouver type B1 or C periprosthetic fracture. Locking and conventional plates were applied for 21 and 19 patients, respectively. RESULTS: No significant difference was found between locking and conventional plate groups in Merle d' Aubigné hip score, walking ability, operation time, and blood loss. Regarding postoperative complications, delayed union was noted in one patient in the locking plate group and subsidence of the stem in one in the conventional plate group. On the final follow-up, bone union was achieved in all patients. CONCLUSION: We cannot suggest the usefulness of locking plate for periprosthetic femoral fracture. However, functional training was performed in the same rehabilitation schedule in our comparative study. Considering the angle stability of the locking plate, weight may be loaded on the locking plate, earlier than that on the conventional plate, which may be an advantage of the locking plate.