Limb length discrepancy is caused by either congenital or acquired conditions,such as growth arrest,osteomyelitis,trauma or tumor.Conventional Limb lengthening utilizes external fixators which lead to great inconvenience to patient's daily life.Complications are however common including pin-site infection,soft tissue tethering from the pins and wires resulting in pain,regenerate deformity or fracture after frame removal and intolerance of the frames.In order to reduce the time of external fixator treatment,various combinations techniques of both external and internal fixation have been developed.However,there is still a risk of deep infection of the implant due to contamination of the previous pin tracts of the external fixation.Fullly implantable intramedullary lengthening nail can avoid the problems of external fixator,including discomfort,pin sites infection,muscular transfixation and soft tissue tethering.There are still some problems including serious pain,too quick lengthening and authorization,so the earlier generations of products could not be safely and widely used.The newest generation of magnetic intramedullary lengthening nail represented by PRECICE (NuVasive,Inc.,Irvine,CA,USA) has obtained good early clinical results with its stability,precision and controllability.PRECICE is broadly used in the world,which may become the new direction of treatment for limb lengthening and deformity correction.This article aims to review the recent development of fully implantable intramedullary lengthening nail,including clinical application,preoperative planning,key points of surgery,postoperative rehabilitation,and complications.

Closed reduction percutaneous screw fixation offers significant biological and biomechanical advantages and can be employed independently for the surgical treatment of pelvic acetabular fractures, as well as serving as a complementary method to open reduction internal fixation. The osseous fixation pathway (OFP) constitutes the anatomical foundation for the minimally invasive approach to pelvic and acetabular fracture management. The pelvis's OFP can be categorized into anterior, middle, and posterior parts. The anterior OFP encompasses both the superior pubic/anterior column and inferior pubic OFPs. The former is primarily utilized for addressing transverse and T-shaped acetabular fractures, as well as anterior column and superior pubic fractures. The latter is predominantly applied to inferior pubic fractures. The middle OFP includes the anterior inferior iliac spine to the posterior iliac crest (LC-II) OFP, the gluteus medius column OFP, and the iliac crest OFP. The LC-II OFP is primarily designated for pelvic crescent, iliac wing, and select high anterior column acetabular fractures. The gluteus medius column OFP is used for the treatment of some iliac fractures or acetabular fractures. And the iliac crest OFP is used for the treatment of simple iliac wing fractures or acetabular fractures involving the iliac crest. The posterior OFP includes the posterior column of the acetabulum OFP, sacroiliac OFP, and sacral OFP. The posterior column of the acetabulum OFP is used for the treatment of acetabular fractures involving the posterior column; the sacroiliac OFP is mainly utilized for a range of pelvic injuries, including pelvic rotational or vertical unstable pelvic injury, sacroiliac dislocation or fracture dislocation; open injury of the posterior ring of the pelvis with relatively mild contamination; elderly sacral (incomplete) fractures; residual gap at the end of sacral fracture after pubic symphysis and plate internal fixation; certain traumatic spinopelvic dissociation ; in combination with lumbopelvic fixation for the treatment of pelvic fractures with lumbosacral junction injury. Sacral OFP is advised for treating bilateral sacroiliac dislocation and certain crescent-like pelvic fractures; bilateral sacral fractures; sacral fractures involving Denis III zone, osteoporotic sacral incomplete fractures. The pursuit of minimally invasive treatment modalities for pelvic and acetabular fractures comes with challenges. A comprehensive understanding of OFP morphology and intraoperative imaging, coupled with a commitment to enhancing fracture reduction quality and surgical proficiency, is imperative for the precise management of such injuries.

The development of modern science and technology continues to promote the advancement of surgical methods, the era of surgical surgery led by robots has arrived. Orthopaedic positioning robot is a kind of auxiliary treatment equipment to realize surgical planning by means of spatial mapping of target images. It is composed of movable robotic arm, optical tracking device and surgical planning navigation system. During the operation, the path navigation of surgical instruments can be planned and implemented according to the predetermined procedure, and the precise placement of orthopedic internal fixation can be completed with the participation of the surgeon. It is mainly used in trauma orthopaedics, joint replacement and spine surgery fields. It has clinical advantages such as accurate operation, stable performance and good repeatability. Robot assisted minimally invasive pelvic acetabular fracture surgery is mainly realized by assisted placement of the LC-II screw, sacral iliac screw, iliac lumbar triangular fixation, iliac lumbar fixation, acetabular anterior column screw, acetabular posterior column screw, Magic screw and other osseous fixation pathway screws. It has the advantages of relatively simple operation, small systematic error, accurate spatial positioning and safe screw insertion. The clinical introduction of robot-assisted surgery provides effective solutions and advanced technical supports for optimizing the surgical treatment of pelvic acetabular fractures and promoting the enhanced recovery after surgery. The continuous improvement of the application level of robots has created favorable conditions and technical support for promoting the development of intelligent, individualized, minimally invasive and precise treatment of pelvic and acetabular fractures.

Periprosthetic fracture of femur is the most common postoperative complication after total knee arthroplasty (TKA). Risk factors for periprosthetic fractures include female sex, osteoporosis/osteopenia, rheumatoid arthritis, osteoarthritis, neuromuscular disease, cognitive disorder, chronic use of corticosteroids, obesity, advanced age, infection, osteolysis around the prosthesis, knee joint ankyloses, notching of the anterior femoral cortex, etc. According to epidemiological research, the incidence of femoral periprosthetic fractures following TKA ranges from 0.3% to 2.5%. Lewis and Rorabeck classifications, the most commonly used classification of periprosthetic fractures of the femur, introduce the concept of prosthesis loosening and emphasize the ecessity of revision surgery. Other classifications include Su typing, Universal Typing System, and Rhee typing, the latest of which is the Kim typing proposed in 2022. Treatment strategies for periprosthetic femoral fractures after TKA include nonsurgical treatment, external fixation techniques, single-plate fixation, double-plate fixation, intramedullary nail fixation, and revision TKA and distal femur replacement. The purpose of this paper is to better guide the prevention and treatment of periprosthetic fractures after TKA by searching and analyzing relevant literature on periprosthetic fractures after TKA.

Objective To explore the surgical methods and evaluate the postoperative outcomes after cerclage cables and long cephalomedullary nails fixation with minimally invasive technique for the treatment of subtrochanteric femoral fractures.Methods From January 2013 to February 2016,21 patients with subtrochanteric femoral fractures surgically treated were retrospectively analyzed.There were 14 males and 7 females with an average age of 43.5 years old (ranged from 24 to 71 years old).11 patients suffered by traffic accidents,8 patients fell down from heights and 2 patients injured by collapses of heavy objectives.Subtrochanteric fractures were classified by Seinsheimer classification with 2 cases of type] B,5 cases of type Ⅱ C,7 cases of Ⅲ A,2 cases of Ⅲ B,1 case of Ⅳ and 4 cases of Ⅴ.CT scans of bilateral femurs were performed to measure the length,canal diameter and anterior ache before the operation.All the fractures were treated by cerclage cables and long cephalomedullary nails with minimal invasive technique.7 cases were fixed by one cable and 14 cases by two or more cables.Results All the patients were followed up with an average of 22.5 months (ranged from 12 to 36 months).The healing time of 20 patients was 3-6 months,with an average time of 4.1 months,except 1 was union by re-operation and the healing time was 13 months after initial operation.According to Harris function evaluation,the average score was 85.4 (ranged from 68 to 97).The clinical outcomes were rated with excellent in 13 cases,good in 6 cases,fair in 1 case and poor in 1 case.The excellent and good rate was 90.5％.Complications included 1 case of screw cut-out and 1 case of nonunion.Conclusion For the treatment of subtrochanteric fractures with spiral,oblique pattern or a big butterfly fragment,satisfactory outcome could be achieved by fixation of cerclage cables and long cephalomedullary nails.The key to healing is to protect the blood supply of the fracture fragments with minimally invasive technique.

The tibial plateau fractures is basically characterized by the collapse and split of the articular surface, increasing the difficulty of surgical reduction and fixation.The complex soft tissue structure adjacent to the tibial plateau prevents the reduction and fixation of tibial plateau fractures. The injuries associated with the fracture and surgical approach also aggravate the loss of knee joint stability. Therefore, the bony reconstruction and soft tissue protection of the knee joint have been the difficulties during the operation of tibial plateau fractures. The authors review the literatures relevant to the progress in surgical management of tibial plateau fractures from aspects of surgical approach, internal and external fixation technology, application of arthroscopic technique, balloon angioplasty, total knee arthroplasty, digital orthopedic technology and repair of soft tissue injury, hoping to provide references for clinical treatment of tibial plateau fractures.

Treatment of large bone defects and nonunion induced by various causes requires bone graft, and autologous iliac bone graft has always been considered as the gold standard for the treatment of bone transplantation. However, there exist problems such as postoperative pain and numbness in the donor area or insufficient bone taking. The application of reamer-irrigator-aspirator（RIA）technique can reduce complications in the donor area and collect a maximum of 90 ml of autologous bone to treat large bone defects. In addition, it can also be used to remove the infected lesion and residual bone cement in the medullary cavity. The authors review the instrument structure, operation process, clinical application and complications of RIA technique, so as to provide a reference in the treatment of bone defects and intramedullary canal infection.

Objective:To investigate the importance of measuring and restoring distal radius tear drop angle in the treatment of distal radius middle column fracture with anterior collapse of lunate fossa joint.Methods:Thirty one cases of distal radius fractures in 29 patients was reported for 2 years from January 2018 to January 2020. Two patients with both distal radius fractures were included in this study. All cases in this group were treated by operation. Among the 29 patients, there were 20 males and 9 females. Their ages were 44.9±15.1 years (ranged from 20 to 78 years). Two patients with both distal radius fractures were included in this study, due to both teardrop angle (TDA) reduced. The time from injury to operation was 4-17 d, with an average of 6.9 d. Except for 2 cases of fracture with simple volar approach, the other cases were treated with combined volar and dorsal approach. All patients were treated with open reduction and internal fixation with plates and bone grafting. The teardrop angle was measured before and after operation, and the effect of surgical recovery of teardrop angle was compared. The wrist function was evaluated by Gartland-Werley scores.Results:The wounds of all patients healed in one stage without postoperative infection. The follow-up time of 29 patients were 15.1±5.2 months, ranged from 7 to 31 months. The healing time for all fractures was 10.3±2.9 weeks (from 8 to 16 weeks). No fracture nonunion or redisplacement. In 31 cases, the tear drop angle was 33.4°±5.83° (20°-45°) before operation, and 58.9°±9.89° (35°-70°) after operation. At the end of follow-up, Gartland-Werley scores was 4.7±4.6, ranged from 0 to 17. Among them, 10 cases were excellent, 16 were good, 5 cases were fair, and the excellent and good rate was 83.9%. The Gartland-Werley scores of the two subgroups with postoperative tear drop angle recovery ≥50° and <50° were compared, and the results were significantly different (the excellent and good rate for two subgroups were 96.2% and 20.0% respectively ( P=0.001). Conclusion:The distal radius fracture with significantly reduced tear drop angle should be actively treated. The measurement and recovery of tear drop angle is an important factor affecting the functional outcome of distal radius fracture with anterior edge collapse of lunate fossa joint, which should be highly concerned by clinical doctors. The recovery of teardrop angle mostly requires dorsal approach.

Bone defects are usually resulted from traumatic injuries,infections,and bone tumors.The treatments mainly include autologous bone graft,allograft bone graft,distraction osteogenesis,vascularized bone grafting and amputation.All of the procedures show their inherent limitations due to different operative indications and different surgical techniques.The emergence of Masquelet technique provides a simple,safe,and more cost-effective solution in treating bone defects.The present article reviews the relevant literatures and summarizes the progress of Masquelet technique in the treatment of bone defects.The technique mainly includes two-step process which involves the induction of the induced membrane prior to the introduction of graft material into induced membrane.The first stage involves radical debridement of all infected or necrotic tissue,fracture stabilization,and filling the segmental bone defect with a cement spacer,composed of polymethyl methacrylate (PMMA) cement.Based on the results of culture performed on the wound samples,the sensitive antibiotics are mixed with cement for the infected bone defect.The second stage of bone grafting is performed within 6-8 weeks after the primary surgery.A longitudinal incision is performed through the induced membrane.The cement spacer is removed carefully and autogenous cancellous bone graft is placed to fill the bone defect and to close the induced membrane.A large number of experimental studies and clinical observations show that the induced membrane is a highly vascularized biological membrane rich in vascular endothelial growth factor (VEGF),transforming growth factor-β1(TGF-β1),bone morphogenetic protein 2 (BMP-2) and other growth factors,which can promote bone regeneration and repair.Masquelet technique can effectively treat multiple parts of posttraumatic bone defects,infectious bone defects,bone defects after tumor resection,congenital tibial pseudarthrosis,and so on.Masquelet provide a choice to treat bone defect for maxillofacial.The complications of Masquelet technique include infection recurrence,bone graft absorption,nonunion and pseudarthrosis.This study is to summarize the recent development of Masquelet technique,and to provide theoretical guidance for the application of Masquelet technique.

Objective:To investigate the clinical outcomes of fragility fractures of the pelvis (FFP) treated with robot-assisted screws, minimally reduction according to the pelvic osseous pathways.Methods:A retrospective analysis was performed on the data of 50 elderly patients with FFP treated by the Department of Trauma and Pelvic Trauma of Tianjin Hospital from March 2016 to October 2021, and the 50 patients with FFP were divided into robotic-assisted screw fixation group (robot group) and open reduction steel plate fixation group (open group) according to the fixation method. There were 30 patients in the Robot group, 6 males and 24 females, average age 75.03±7.32 years (range, 60-90 years). According to Rommens and Hofmann FFP classification, there were 4 cases of IIc type, 8 cases of IIIa type, 1 case of IIIb type, 12 cases of IIIc type, 3 cases of IVa type, 2 cases of IVb type. There were 20 patients in the open group, 5 males and 15 females, average age 71.90±5.51 years (range, 62-85 years). According to Rommens and Hofmann FFP classification, there were 2 cases of IIc type, 6 cases of IIIa type, 9 cases of IIIc type, 3 cases of IVa type. The two groups were compared with age, pelvic fracture classification, operation time, intraoperative blood loss, fracture reduction quality, visual analogue scale (VAS), Majeed score, and wound healing or not.Results:All patients were followed up for 12.72 months (range, 6-24 months). In the robot group, the operation time was 50.17±19.32 min (range, 30-120 min), and intraoperative blood loss was 55.50±28.60 ml (range, 10-150 ml); in the open group, the operation time was 92.25±27.55 min (range, 60-180 min), and intraoperative blood loss was 217.50±67.20 ml (range, 150-400 ml), there were statistical differences ( t=6.36, P<0.001; t=11.72, P<0.001). According to Mears and Velyvis imaging evaluation criteria, in the robot group, anatomical reduction were achieved in 10 cases, satifactory reduction were achieved in 20 cases; in the open group, anatomical reduction were achieved in 14 cases, satifactory reduction were achieved in 6 cases, there were statistical differences (χ 2=6.46, P=0.011). In the robot group, VAS for pelvic pain was 7.33±1.32 points (range, 4-9 points) before operation, 4.13±1.07 points (range, 3-8 points) one week after surgery, and 2.30±0.84 points (range, 1-5 points) at the last follow-up; in the open group, VAS for pelvic pain was 7.45±1.23 points (range, 5-9 points) before operation, 5.25±1.25 points (range, 3-8 points) one week after surgery, and 2.80±1.24 points (range, 1-6 points) at the last follow-up, the difference between the two groups was statistically significant ( F=162.18, P<0.001; F=70.18, P<0.001), the difference between the two groups was statistically significant 1 week after surgery ( t=3.37, P=0.001), and there was no statistically significant difference between the two groups before surgery and the last follow-up ( P>0.05). The Majeed score was 82.10±4.80 (range, 65-95) in the robot group, 77.60±5.40 (range, 70-93) in the open group at the last follow-up, there were statistical differences ( t=3.09, P=0.003). There was no wound complication in the robot group, there were 4 cases with wound infection or rupture in the open group. One LC-II screw loosen in the robot group, which needed reoperation with cement, there was also 1 screw of plate loosening in the open group with no reoperation. Conclusion:Robot-assisted screws fixation with minimally reduction based pelvic osseous pathways shows satisfactory clinical outcomes, satisfactory reduction, effective pain relief, and fewer postoperative complications in treatment of elderly FFP.