Less Invasive Stabilization System Research Articles

Management of segmental defects post open distal femur fracture using a titanium cage combined with the Masquelet technique A single-centre report of 23 cases

IntroductionThe segmental bone defects post open distal femur fracture presents a reconstructive challenge, which often requires extreme solutions. The present study reviewed a new treatment strategy which used a cylindrical titanium mesh cage as an adjunct to the Masquelet technique. MethodsWe retrospectively reviewed a consecutive series of 23 patients treated for segmental bone defects post open distal femur fracture using a titanium mesh cage combined with the Masquelet technique under a 2-staged protocol in our institution from 2017 to 2021. The study group consisted of 13 men and 10 women with an average age of 44.1 years. The surgical debridement was performed with antibiotic polymethylmethacrylate (PMMA) cement spacer implanted into the bone defect combined with cement-wrapped plate stabilization, or antibiotic beads with vacuum sealing drainage (VSD) to cover the wound. The second stage of the Masquelet technique for bone defect repair began at least 4–6 weeks after the first stage, once all signs of possible infection were eliminated. After the cement spacer was removed, the definitive reconstruction was completed with exchange to a cylindrical titanium mesh cage filled with cancellous autograft within the induced membrane. The bone defect with cage was stabilized with a distal femoral Less Invasive Stabilization System (LISS). The radiological and clinical records of the enrolled patients were retrospectively analyzed. ResultsThe mean follow-up was 38.6 months. The average number of operations before the second stage was 1.3. The mean interval between the two stages was 12.7 weeks. The average length of the defect measured 8.3 cm (ranging from 6.1 to 12.4 cm). All the defects filled with autograft within the cage achieved bony union, with a mean healing time of 8.4 months. At the latest follow-up, the mean knee extension measured 6.2° (ranging from 0° to 20°), and the mean flexion measured 101.8° (ranging from 60° to 120°). Complications included two instances of superficial stitch abscess, which eventually healed. ConclusionsThe use of a titanium cage implanted into an induced membrane in a 2-staged Masquelet protocol could achieve satisfactory clinical outcomes in cases of segmental defects following open distal femur fractures.

Application of Cortical Bone Plate Allografts Combined with Less Invasive Stabilization System (LISS) Plates in Fixation of Comminuted Distal Femur Fractures.

Background and Objectives: At present, the management of comminuted distal femur fractures remains challenging for orthopedic surgeons. The aim of this study is to report a surgical treatment for comminuted distal femur fractures using supplementary medial cortical bone plate allografts in conjunction with the lateral less invasive stabilization system (LISS) plates. Materials and Methods: From January 2009 to January 2014, the records of thirty-three patients who underwent supplementary medial cortical bone plate allografts combined with lateral LISS plates fixation were reviewed. Clinical and radiographic data were collected during regular postoperative follow-up visits. Functional outcomes were determined according to the special surgery knee rating scale (HSS) used at the hospital. Results: Thirty patients were followed for 13 to 73 months after surgery, with an average follow-up time of 31.3 months. The mean time to bone union was 5.4 months (range of 3-12 months) and the mean range of knee flexion was 105.6° (range of 80-130°). Of the remaining patients, 10 had a score of "Excellent", while 10 had a score of "Good". Three patients had superficial or deep infections, one patient had nonunion that required bone grafting, and one patient had post-traumatic knee arthritis. Conclusions: Based on these promising results, we propose that supplementary medial cortical bone plate allografts combined with lateral LISS plate fixation may be a good treatment option for comminuted distal femur fractures. This treatment choice not only resulted in markedly improved stability on the medial side of the femur, but also satisfactory outcomes for distal femoral fractures.

Failure of Distal Femoral Locking Plate: Case Report

The Less Invasive Stabilization System (LISS) and titanium distal femoral locking compression plate (DF-LCP) was designed by the AO Group to combine the advantages of both interlocked intra-medullary nailing and biological plating techniques in one system. The stiffness of the construct is similar to a 95° condylar plate, dynamic condylar screw, or condylar buttress plate.
 We report a case of the DF-LCP and screw breakage. Early weight bearing and lack of callus consolidation precipitated failure of the implant. Non-weight bearing and early autologous bone grafting may be indicated in open distal femoral fractures.

Periprosthetic knee fractures in an elderly population: open reduction and internal fixation vs distal femur megaprostheses.

The incidence of periprosthetic fractures of distal femur (PPDFFx) after primary total knee arthroplasties is described around 0.3% and 2.5% and it is increasing as the number of patients with total knee arthroplasty continues to arise. surgical options treatments for PPDFFx include fixation in the form of eather Open reduction and internal fixation (ORIF), or retrograde intramedullary nailing (RIMN), or conventional (non locked) plating, or locked plating such as the Less Invasive Stabilization System (LISS), or dynamic condylar screws. In recent years, however, the use of megaprostheses has been increasing. Patients with periprosthetic fractures of distal femur after primary total knee arthroplasties treated with ORIF or with the use of Distal femur replacement (DFR) were retrospectively analyzed in this to evaluate differences in intra-operative blood loss, need of blood trasfusion, weight bearing, range of motion, rate of complications, rate of revision surgery and functional outcome according Oxford Knee Score between two groups. Treatment of Periprosthetic distal femur fracture remains controversial. While ORIF seems to guarantee less percentage of complications and reoperation rate, those treated with megaprosthesis seem to gain better range of motion in a very short post-operative time. In the future it will be necessary to investigate with greater numbers possible advantages and disadvantages of the various treatments in periprosthetic distal femur fractures.

Evaluation of the Results of Minimally Invasive Plate Osteosynthesis Using a Locking Plate in the Treatment of Distal Femur Fractures.

IntroductionDistal femur fractures are serious injuries that can be difficult to treat, carry an unpredictable prognosis, and lead to long-term disability and morbidity. The introduction of minimally invasive plate osteosynthesis (MIPO) avoids direct exposure of the fracture site, improves fracture healing and decreases the incidence of complications. The aim of this study was to assess prospectively the early results of the treatment of supracondylar fractures of the femur using minimally invasive percutaneous osteosynthesis using a distal femoral locking plate. The study was a prospective study that included 20 adult patients who sustained distal femur fractures.Materials and methods The study was a prospective study that included 20 patients suffering from supracondylar fractures of the femur. All patients had fixation of the fracture using a distal femur locking plate (less invasive stabilization system (LISS)) in a minimally invasive technique using an anterolateral or direct lateral approach to the distal femur according to the fracture classification. The follow-up was done using the functional evaluation scale for distal femoral fractures as regards range of motion, deformation, pain, walking ability, and return to work.ResultsThe mean age was 52.80 (19-80) years. The mean body mass index of the patients was 28.50, with a range of 23-43 kg/m2. The mechanism of trauma was road traffic accidents (RTAs) in nine patients (45%) and falling from standing height in eleven patients (55%). Fractures were classified according to the Arbeitsgemeinschaft Osteosynthesefragen-Orthopedic Trauma Association (AO-OTA) classification. All patients were followed up for a period of six months and assessed in terms of knee range of motion, deformation, pain, walking ability, and return to work. The mean time of radiological union, in which bony trabeculae crossed the fracture gap, was 3.45 ± 0.79 months. The final results obtained were excellent in four patients (20%), good in nine patients (45%), fair in five patients (25%), and poor in two patients (10%). Complications encountered were knee stiffness (20%), superficial wound infection (10%), and shortening (15%).ConclusionLISS plating using the MIPO approach is useful in treating complex distal femoral fractures. Large studies from independent centers reporting long-term results are needed to further evaluate the role of LISS plating and the MIPO approach in the management of complex distal femoral fractures.

Treatment of Periarticular Fractures of the Knee Using the Less Invasive Stabilization System: A Retrospective Clinical Trial.

IntroductionPeriarticular fractures of the knee in adults are generally treated with internal fixation. The Less Invasive Stabilization System (LISS) plate, developed by Arbeitsgemeinschaft Osteosynthesefragen (AO)/Association for the Study of Internal Fixation (ASIF) in the late 1990s, allows reduction and biological fixation through smaller incisions without violating periosteal blood supply. It offers several advantages for the treatment of complex periarticular fractures of the knee. In this study, we have aimed to report the results of a single series of these fractures.Materials and methodsForty-eight patients with AO type 33 and AO type 41 periarticular knee fractures who were operated between 2009 and 2014 at a single institution were included in this retrospective study. Patient demographics, fracture epidemiology, intraarticular extension, concomitant injuries, American Society of Anesthesiologists (ASA) score, time to union, the average time from admission to surgery, and the mean time from operation to patient discharge were noted. The effect of patient and fracture-related factors on length of hospital stay were evaluated.ResultsThe mean follow-up time was 23.7 (12-48) months. The average time from admission till surgery and from surgery till discharge was 10.2 (1-39) and 9.7 (2-35) days, respectively. The average time for union was 6.8 months. Femur fractures healed in mean 6.6 months whereas tibia fractures took 7.1 months to heal. Time from admission to surgery and postoperative hospital stay was longer in patients with higher ASA scores (p<0.01) and open fractures (p<0.001). Patients’ body mass index (BMI) and intraarticular extension of the fracture did not cause an increase in either preoperative or postoperative hospital stay (p>0.05). The presence of concomitant major injuries caused a delay in operation (p<0.05), whereas postoperative hospital stay was not different (p>0.05).ConclusionLISS plating provides good stability through a small incision, permits biological fracture healing, may be used in multifragmentary fractures and has low complication rates. It is a good alternative for the treatment of periarticular fractures of the knee.

Comparative analysis of the biomechanical behavior of anterograde/retrograde nailing in supracondylar femoral fractures

Supracondylar femoral fractures account for a noticeable percentage of the femoral shaft fractures, affecting two etiological groups: high energy trauma in young men, with good bone quality, and older women with osteoporotic femur. Surgical treatment of those kind of fractures remains controversial, with different surgical options such as plate and sliding barrel locking condylar plate, less invasive stabilization system (LISS) or intramedullary nailing, which has emerged as a new fixation choice in the treatment of that type of fractures.The present work performs a comparative study about the biomechanical behavior of anterograde and retrograde nailing in supracondylar femoral fractures type A, in order to determine the best choice of nailing and locking configuration. A three-dimensional finite element model of the femur was developed, modeling femoral supracondylar fracture and different nailing configurations, both for anterograde and retrograde nails. The study was focused on the immediately post-operative stage, verifying the appropriate stability of the osteosynthesis.The obtained results show a better biomechanical behavior for anterograde nails, providing a better stability from the point of view of global movements, lower stresses in screws, and less stress concentration in cortical bone. So, for the analyzed fractures and osteosyntheses types, anterograde nailing has demonstrated to be a better surgical option, being an excellent indication in supracondylar fractures of femur, with clear benefits compared to retrograde nailing, providing a better stabilization which enables for a more satisfactory fracture healing.

Analyse par éléments finis de trois systèmes de fixation de fractures sous trochantériennes stables ou instables

BackgroundThe optimal type of fixation implant for managing subtrochanteric fractures (STFs) is debated, as uncertainty continues to surround the comparative biomechanical performance of the proximal femoral nail antirotation (PFNA), proximal femoral locking plate (PFLP), and reverse less invasive stabilisation system (LISS). No studies have used finite element analysis (FEA) to compare these three devices. The objective of this study was to use FEA to compare the PFNA, PFLP, and LISS used to treat STFs based on the following criteria: (1) stress distribution on the femur and implant, (2) peak stress and stress on the medial side of the femur near the fracture site, and (3) smallest axial displacement of the femoral head. HypothesisOf the three implants, the PFNA has the best biomechanical performance when used for STF fixation. MethodsFEA was used to assess synthetic bone responses to the three implants used to fix three STF types, namely, Seinsheimer I, III, and IV, characterised by increasing bone loss and/or comminution with subsequent instability. Loading was with 1400N axial compression force. ResultsThe LISS and PFLP exhibited similar biomechanical properties in all three fracture types. However, with the Seinsheimer IV fracture, the triangular configuration of the PFLP resulted in stress concentration at the medial and lateral sides of the implant junction. With the Seinsheimer I and III fractures, the PFNA resulted in higher peak stress (183.85MPa and 364.58MPa, respectively) compared to the PFLP (102.90MPa and 177.52MPa) and LISS (116.55MPa and 227.97MPa). With the Seinsheimer IV fracture, peak stress was highest with LISS (2310.40MPa) and was higher with PFLP (2054.90MPa) than with PFNA (1313.30MPa). With the Seinsheimer I and III fractures, the axial femoral head displacement was greater with the PFNA (0.74mm and 1.13mm, respectively) than with the PFLP (0.48mm and 1.02mm) and LISS (0.52mm and 0.92mm). With the Seinsheimer IV fracture, in contrast, the PFNA produced less axial femoral head displacement (4.1mm) compared to the PFLP (12.03mm) and LISS (16.56mm). DiscussionWith unstable (Seinsheimer IV) STFs, fixation stability was better with the PFNA compared to the PFLP and LISS. In contrast, with stable STFs (Seinsheimer I and III), the PFLP and LISS offered greater stability, with similar biomechanical effects. However, with Seinsheimer III fractures, the stress on the implant-femur interface was greater with the LISS. Level of evidenceIV, basic science study.

Identification of the lateral femoral safe zone for drilling during LISS plate fixation of distal femur fractures

BackgroundThe incidence of arterial injury associated with femoral fractures is approximately 1%. Lateral sub-muscular plate fixation is gaining popularity for the management of distal femoral fractures. The objective of this study was to assess the iatrogenic risk to the superficial femoral artery (SFA) during Less Invasive Stabilisation System (LISS) plate fixation of distal femoral fractures by analysing the range of distances and angles between LISS plate screws and the drilling line to the SFA. Materials and methodsWe identified all patients who underwent LISS plate fixation of distal femoral fractures between 2008 and 2018 in our level-1 trauma centre. Patients who underwent postoperative computed tomography for any reason were eligible for inclusion in the study. Twenty-five patients met the inclusion criteria. The sample comprised 10 male and 15 female patients with a mean age of 55 years. The most common fracture type was a supracondylar femur fracture (56%), followed by an intercondylar fracture (36%). A 13-hole LISS plate was the most common plate length used (44%). A consultant radiologist reviewed all scans to verify the visibility and marking of the SFA. ResultsThe median distance between the screw tip and the SFA was 21 mm (range, 8–65 mm). There was a negative correlation between the LISS plate hole number and the trajectory of drilling (Pearson coefficient: −0.87, p < 0.001). Using a linear regression model, the SFA was more likely to be in the line of drilling when the 6th to 10th holes in the LISS plate were used. ConclusionExtra care is needed when drilling into the LISS plate holes from the lateral to the medial direction in order to reduce the risk of iatrogenic injury to the SFA, especially in the high-risk plate zone where the artery can be close to the drilling line.

Early effectiveness of mini-Swashbuckler approach for distal femoral type C fractures

To explore the early effectiveness and advantages of mini-Swashbuckler approach in treatment of distal femoral type C fractures by comparing with Swashbuckler approach. A retrospective analysis was made on 43 patients with distal femoral type C fractures between January 2014 and June 2018. Twenty-two patients were treated with open reduction via mini-Swashbuckler approach and internal fixation with less invasive stabilization system (LISS) plate in modified group; and 21 patients were treated with open reduction via Swashbuckler approach and internal fixation with LISS plate in traditional group. There was no significant difference in age, gender, cause of trauma, fracture classification, fracture side, interval between injury and operation, and complications between the two groups ( P>0.05). The operation time, intraoperative blood loss, intraoperative fluoroscopy times, hospitalization time, fracture healing time, Hospital for Special Surgery (HSS) scores of the knee, and postoperative complications were recorded and compared between the two groups. The operation successfully completed in both groups. The operation time of the modified group was significantly longer than that of the traditional group, the fluoroscopy times was increased and the blood loss was reduced, the differences were significant ( P<0.05). There was no significant difference in hospitalization time between the two groups ( t=0.277, P=0.783). All patients in the two groups were followed up 6-8 months, with an average of 7.2 months. Fractures healed in both groups, there was no significant difference in healing time between the two groups ( t=0.861, P=0.394). The HSS scores of the modified group were 82.91±2.88 and 89.28±3.63 at 3 and 6 months after operation, respectively, which were superior to those of the traditional group (74.62±3.64) and (81.48±4.55) ( t=8.306, P=0.000; t=6.231, P=0.000). There was 1 case of incision infection, 1 case of deep vein thrombosis, and 2 cases of knee flexion and extension dysfunction in traditional group, and 1 case of deep vein thrombosis, 1 case of varus deformity, and 1 case of internal fixation loosening in modified group. There was no significant difference in the incidences of complications between the two groups ( P>0.05). Compared with Swashbuckler approach, mini-Swashbuckler approach has limited visual field exposure, which leads to prolonged operation time and increased fluoroscopy times, but the risks of complications do not increase. Because of its small soft tissue injury and less blood loss, it is conducive to the recovery of knee joint function after operation.

Comparative finite element analysis of three implants fixing stable and unstable subtrochanteric femoral fractures: Proximal Femoral Nail Antirotation (PFNA), Proximal Femoral Locking Plate (PFLP), and Reverse Less Invasive Stabilization System (LISS)

BackgroundThe optimal type of fixation implant for managing subtrochanteric fractures (STFs) is debated, as uncertainty continues to surround the comparative biomechanical performance of the proximal femoral nail antirotation (PFNA), proximal femoral locking plate (PFLP), and reverse less invasive stabilisation system (LISS). No studies have used finite element analysis (FEA) to compare these three devices. The objective of this study was to use FEA to compare the PFNA, PFLP, and LISS used to treat STFs based on the following criteria: (1) stress distribution on the femur and implant, (2) peak stress and stress on the medial side of the femur near the fracture site, and (3) smallest axial displacement of the femoral head. HypothesisOf the three implants, the PFNA has the best biomechanical performance when used for STF fixation. MethodsFEA was used to assess synthetic bone responses to the three implants used to fix three STF types, namely, Seinsheimer I, III, and IV, characterised by increasing bone loss and/or comminution with subsequent instability. Loading was with 1400N axial compression force. ResultsThe LISS and PFLP exhibited similar biomechanical properties in all three fracture types. However, with the Seinsheimer IV fracture, the triangular configuration of the PFLP resulted in stress concentration at the medial and lateral sides of the implant junction. With the Seinsheimer I and III fractures, the PFNA resulted in higher peak stress (183.85MPa and 364.58MPa, respectively) compared to the PFLP (102.90MPa and 177.52MPa) and LISS (116.55MPa and 227.97MPa). With the Seinsheimer IV fracture, peak stress was highest with LISS (2310.40MPa) and was higher with PFLP (2054.90MPa) than with PFNA (1313.30MPa). With the Seinsheimer I and III fractures, the axial femoral head displacement was greater with the PFNA (0.74mm and 1.13mm, respectively) than with the PFLP (0.48mm and 1.02mm) and LISS (0.52mm and 0.92mm). With the Seinsheimer IV fracture, in contrast, the PFNA produced less axial femoral head displacement (4.1mm) compared to the PFLP (12.03mm) and LISS (16.56mm). DiscussionWith unstable (Seinsheimer IV) STFs, fixation stability was better with the PFNA compared to the PFLP and LISS. In contrast, with stable STFs (Seinsheimer I and III), the PFLP and LISS offered greater stability, with similar biomechanical effects. However, with Seinsheimer III fractures, the stress on the implant-femur interface was greater with the LISS. Level of evidenceIV, basic science study.

Comparison of two reduction strategies in treatment of distal femoral fracture with less invasive stabilization system

Objective To evaluate the feasibility of a new reduction technique by comparing 2 reduction strategies in the treatment of distal femoral fractures with less invasive stabilization system (LISS). Methods A retrospective study was performed on the clinical data of 31 patients with distal femoral fracture who had been treated with LISS at Department of Orthopedics, Huadong Hospital Affiliated to Fudan University from January 2014 to December 2016. They were 11 males and 21 females. In 21 of them reduction of the fracture ends was conducted before fixation of the distal femur (strategy one), involving 9 males and 12 females with an age of 73.2±16.2 years; in the other 10 of them reduction of the fracture ends was conducted after fixation of the distal femur (strategy two), involving 2 males and 8 females with an age of 70.8±20.4 years. The 2 groups were compared in terms of perioperative blood loss, operation time, postoperative complications and the modified Hospital for Special Surgery (HSS) score of the affected knee joint. The enumeration data were compared with Fisher exact test and the measurement data with t-test. Results The 2 groups were compatible due to the insignificant differences in their preoperative general data (P>0.05). There were no significant differences between the 2 groups in terms of perioperative blood loss (593.3±99.1 mL versus 494.7±94.4 mL), operation time (121.7±8.1 min versus 106.4±8.5 min), rate of postoperative complications (0 versus 10%) and modified HSS score of the affected knee joint (83.8±1.4 versus 84.2±3.1) (P>0.05). Conclusions The 2 reduction strategies can lead to similar surgical effects in the treatment of distal femoral fractures with LISS. Strategy two can be a feasible alternative for surgeons with its theoretical advantage of simplicity. Key words: Femoral fracture; Fracture fixation, internal; Bone plate; Less invasive stabilization system; Reduction

Biomechanical analysis of tension-compression asymmetry, anisotropy and heterogeneity of bone reconstruction in response to periprosthetic fracture repair

Introduction. Bone repair after periprosthetic fracture is a critical issue in orthopedics. Objectives. So there is a need for research to provide new medical solutions, especially in the context of population ageing in the Ukraine. The importance of biomechanics which is concerned with the application of principles, concepts and methods of mechanics of solid and fluid to the human body in motion and at rest is well recognized as a foundation for further experimental and theoretical research in the skeletal tissues. Materials and methods. Different aspects of biomechanics require different concepts and methods of mechanics of solid and fluid to be used. Remodeling occurs significantly throughout lifetime of bone that is why it can be regarded as a primary determinant of the mechanical properties of bone and implant. Biomechanical analysis given in this review has been concerned with understanding on how mechanical signals and molecular mechanisms affect the healing of Vancouver periprosthetic femoral fracture of B1 and C-type with the use of internal fixation through a less invasive stabilization system (LISS)-plate, which is screwed into the artificial hip joint. Results. Identification of such parameters as mechanical properties of bone, titanium alloys (hip prosthesis, coating, LISS-plate, screws) and implant/biomaterial interface with bone under mechanical and biochemical loading that are very essential for predicting arthroplasty outcomes were investigated experimentally considering elastoplastic deformation, creep, fatigue and ratcheting, as well as, damage development in materials under discussion. Among the basic deformation features were tension-compression asymmetry, anisotropy and heterogeneity of mechanical properties. We used the three-dimensional finite element model derived from the reconstruction of treatment and magnetic resonance (tomographic) images. Conclusions. As a result of this model analysis, it was found that treatment rate of periprosthetic femoral fractures after total hip arthroplasty with the use of LISS-plates and screws for internal fixation may be controlled by means of ABAQUS (or ANSYS) software package to reproduce the characteristic features of bone and implant in bone reconstruction in order to improve the fracture healing rate and shorten treatment duration Introduction. Bone repair after periprosthetic fracture is a critical issue in orthopedics. Objectives. So there is a need for research to provide new medical solutions, especially in the context of population ageing in the Ukraine. The importance of biomechanics which is concerned with the application of principles, concepts and methods of mechanics of solid and fluid to the human body in motion and at rest is well recognized as a foundation for further experimental and theoretical research in the skeletal tissues. Materials and methods. Different aspects of biomechanics require different concepts and methods of mechanics of solid and fluid to be used. Remodeling occurs significantly throughout lifetime of bone that is why it can be regarded as a primary determinant of the mechanical properties of bone and implant. Biomechanical analysis given in this review has been concerned with understanding on how mechanical signals and molecular mechanisms affect the healing of Vancouver periprosthetic femoral fracture of B1 and C-type with the use of internal fixation through a less invasive stabilization system (LISS)-plate, which is screwed into the artificial hip joint. Results. Identification of such parameters as mechanical properties of bone, titanium alloys (hip prosthesis, coating, LISS-plate, screws) and implant/biomaterial interface with bone under mechanical and biochemical loading that are very essential for predicting arthroplasty outcomes were investigated experimentally considering elastoplastic deformation, creep, fatigue and ratcheting, as well as, damage development in materials under discussion. Among the basic deformation features were tension-compression asymmetry, anisotropy and heterogeneity of mechanical properties. We used the three-dimensional finite element model derived from the reconstruction of treatment and magnetic resonance (tomographic) images. Conclusions. As a result of this model analysis, it was found that treatment rate of periprosthetic femoral fractures after total hip arthroplasty with the use of LISS-plates and screws for internal fixation may be controlled by means of ABAQUS (or ANSYS) software package to reproduce the characteristic features of bone and implant in bone reconstruction in order to improve the fracture healing rate and shorten treatment duration.

Fractures of femoral medial condyle treated with contralateral less invasive stabilization system through a medial-posterior approach

Objective To investigate the therapeutic efficacy of contralateral less invasive stabilization system (LISS) through a medial-posterior approach for fractures of femoral medial condyle. Methods From December 2010 to December 2014, 14 patients with fracture of femoral medial condyle were treated surgically at our department. They were 10 males and 4 females, aged from 33 to 64 years (average, 44.6 years). By AO classification, 10 cases were type 33-B2 and 4 cases type 33-B3. Causes of injury included traffic accident in 7 cases, falling in 6 and heavy object crush in one. Internals from injury to operation ranged from 3 to 10 days (average, 5.4 days). All the patients were treated by open reduction and internal fixation with contralateral LISS plate or T plate through a knee medial posterior approach. Results The 14 patients were followed up for 12 to 24 months (average, 18 months). All fractures got bony healing after 3 to 5 months (average, 3.5 months). No collapse of joint surface, joint stiffness, joint infection, malunion or nonunion occurred. According to the Schatzker-Lambert criteria for functional recovery of the distal femoral fractures, the function of the affected knee was assessed at the last follow-up as excellent in 9 cases, good in 3, fair in one and poor in one. Conclusion Open reduction and internal fixation with contralateral LISS plate through a medial-posterior approach is effective for fractures of femoral medial condyle due to its strong buttress, rigid fixation, advantage for early functional exercise, and satisfactory therapeutic outcome. Key words: Femoral fractures; Fracture fixation, internal; Bone plates; Posterior median approach

Surgical technique for biological fixation of closed segmental tibial fractures by the Less Invasive Stabilization System (LISS).

Introduction: This prospective case series study aimed to assess the value of the Less Invasive Stabilization System (LISS) to treat closed Segmental Tibial Fractures (STFs) using a proposed surgical technique.Materials and methods: Between August 2010 and January 2014, 21 consecutive recently (within 1 week) closed STFs that matched the inclusion criteria were enrolled. Patients were treated with the 13-hole LISS plate. All patients were followed up every 2 weeks for the first 2 months, then every month for the rest of the first 6 months and then every 6 months thereafter. Patients were assessed radiologically during the follow-up appointments and clinically at the final visit by the Lower Extremity Functional Scale (LEFS) to evaluate the result.Results: The mean time to union of the proximal fracture was 15.72 ± 2.78 (range: 12–20) weeks and for the distal fracture was 20 ± 2.22 (range: 16–24) weeks, excluding delayed union in three patients. All patients except the three showed radiological observable callus in a mean duration of 4.95 (range: 3–7) weeks. The mean final follow-up LEFS was 72.4 (range: 60–80).Conclusion: The mean time to union of the proximal fracture was shorter than the distal fracture. The use of LISS to treat closed STFs using the proposed surgical technique has proved to give favorable results. Further studies using the described technique are needed to justify the achieved results.Level of evidence: IV (Prospective case series).

An advanced simulator for orthopedic surgical training.

The purpose of creating the virtual reality (VR) simulator is to facilitate and supplement the training opportunities provided to orthopedic residents. The use of VR simulators has increased rapidly in the field of medical surgery for training purposes. This paper discusses the creation of the virtual surgical environment (VSE) for training residents in an orthopedic surgical process called less invasive stabilization system (LISS) surgery which is used to address fractures of the femur. The overall methodology included first obtaining an understanding of the LISS plating process through interactions with expert orthopedic surgeons and developing the information centric models. The information centric models provided a structured basis to design and build the simulator. Subsequently, the haptic-based simulator was built. Finally, the learning assessments were conducted in a medical school. The results from the learning assessments confirm the effectiveness of the VSE for teaching medical residents and students. The scope of the assessment was to ensure (1) the correctness and (2) the usefulness of the VSE. Out of 37 residents/students who participated in the test, 32 showed improvements in their understanding of the LISS plating surgical process. A majority of participants were satisfied with the use of teaching Avatars and haptic technology. A paired t test was conducted to test the statistical significance of the assessment data which showed that the data were statistically significant. This paper demonstrates the usefulness of adopting information centric modeling approach in the design and development of the simulator. The assessment results underscore the potential of using VR-based simulators in medical education especially in orthopedic surgery.

Anatomical and radiological evaluation of less invasive stabilisation system (LISS) in correlation with knee lateral collateral ligament insertion

IntroductionThe Less Invasive Stabilisation System (LISS) is an angle-stable plate that enables treatment of distal femoral comminuted and periprosthetic fracture. As it is placed through a minimally-invasive lateral approach, lateral knee pain is a commonly described symptom after its application. This study investigates knee lateral collateral ligament (LCL) iatrogenic injury during LISS plate fixation. A cadaver study was performed and a retrospective radiological investigation with the analysis of its clinical application was conducted to evaluate possible knee LCL damage. MethodsThe cadaver study included 13 human lower extremities, treated with LISS. After application, lateral knee side was dissected, implants were removed and distances between the drill holes and LCL origin were measured. In the retrospective radiological evaluation, postoperative X-rays for patients treated with distal femoral LISS plate in the University Hospital Regensburg, Germany from January 2010 to December 2015 were examined. Following a protocol described by Pietrini et al., the LCL origin on postoperative X-rays was calculated, both in lateral and anterior-posterior (AP) view, and distances between the plate and its closest locking screw to the LCL origin were measured. ResultsIn the cadaver study, the mean distance between the closest drilling hole and the ligament origin was 14.0mm (range 9–21mm; SD 3.8mm). Twenty-two patients matched the inclusion criteria for the retrospective radiological study. In lateral view, the mean distance between the origin and the closest locking screw was 6.3mm (range 0–16.4mm; SD 4.7mm); the mean distance between the origin and the plate was 3.1mm (range 0–13.9mm; SD 4.1mm). In AP view, the mean distance between LCL origin and the nearest screw was 2.4mm (range 0–7.6mm; SD 2.4mm). The mean distance between the origin and the most distal locking screw was 9.2mm (range 0–17.5mm; SD 4.0mm). DiscussionThe LISS is a safe option to treat distal femoral fractures in respect to the LCL. Due to close proximity, the LCL might be harmed; therefore, lateral knee pain or lateral instability after implantation should be assessed in further treatment.

One visualization simulation operation system for distal femoral fracture.

A computer-aided 3-dimensional (3D) visualization operation simulation system based on computer-aided design (CAD) Unigraphics NX and Mimics software was established to provide orthopedic surgeons with an actual and reliable system in treating of distal femoral fracture.According to the preoperative CT data, 3D reconstruction of the distal femoral fracture could be achieved by the Mimics software. Then, the CAD Unigraphics NX software was used to measure the model function of all the related surgical instruments, including less invasive stabilization system (LISS) and retrograde intramedullary nail fixation.The function of CAD Unigraphics NX and Mimics software was successful in assisting in the treatment of distal femoral fracture with LISS and retrograde intramedullary nail fixation. The operation procedure was actual, visualized, and lifelike. Moreover, the operation effect could be estimated before surgery.The virtual surgery system may improve the reliability and safety of the operative care of distal femoral fracture.

Inversive LISS plate in treating intertrochanteric and subtrochanteric fractures combined with femoral shaft fractures

To study clinical effects of inversive LISS(less invasive stabilization system, LISS) plate for the treatment of intertrochanteric and subtrochanteric fractures combined with femoral shaft fractures. From January 2012 to January 2015, 24 patients with intertrochanteric and subtrochanteric fractures combined with femoral shaft fractures were treated with inversive LISS plate, included 16 males and 8 females with an average age of 62.5 years old ranged from 35 to 81 years old. There were 8 cases of traffic accident injuries, 3 cases of falling from high place, and 13 cases of falls injuries. The time from injury to operation was ranged from 2 to 12 days with an average of 5.2 days. The operation time, intraoperative blood loss and the length of hospitalization were analyzed. The fracture union was assessed by follow-up radiographs and hip functional recovery by Harris hip scoring. All patients were followed up for 16.2 months (ranged, 18 to 36 months). The mean operative time was (68.22±48.36) min;the mean blood loss was (256.28±182.46) ml;the mean time of hospitalization was(14.8±5.2) days. There were no complications such as deep infection, deep vein thrombosis, pulmonary embolism and bone nonunion during the follow up period. The bone healing was ranged from 3 to 8 months with an average of 4.8 months. The mean Harris score was 76.49±12.28 at the final follow-up, 15 cases were classified as excellent, 6 as good and 3 as fair. Inversive LISS plate can be used in treating with intertrochanteric and subtrochanteric fractures combined with femoral shaft fractures, and should not emphasis on premature loading.

Less invasive stabilization system versus open reduction and internal fixation of closed proximal tibial fractures in adults

Objective The aim of this study was to compare the clinical and radiological outcome between less invasive stabilization system (LISS) and open reduction with internal fixation (ORIF) for the treatment of extra-articular proximal tibia fractures through the lateral approach. Background Proximal tibial fractures present a difficult treatment challenge with historically high complication rates. ORIF has been in vogue for long time with good outcome. However, it is associated with problems, especially overlying skin conditions, delayed recovery, and rehabilitation with limited functional outcome. LISS is an emerging procedure for the treatment of proximal tibial fractures. It preserves soft tissue and the periosteal circulation, which promotes fracture healing. Patients and methods Thirty patients with closed proximal tibial fractures were included in this study. They were randomly divided into two groups. Group I (n = 15) patients were treated with LISS and group II (n = 15) with ORIF. Major characteristics of the two groups were similar in terms of age, sex, mode of injury, fracture location, and associated injuries. All patients were followed up at least 6 months. Results In each group, 12 patients showed union, two patients showed nonunion, and one patient showed delayed union. The mean operative time in LISS patients was 79.3 min, whereas in ORIF patients it was 122 min. All patients of the LISS group were exposed to radiation, whereas only 40% of patients in the ORIF group were exposed to radiation. The mean time of union in LISS patients was 10.87 weeks. However, in ORIF patients, the mean time of union was 21.13 weeks. There was no significant difference between the two groups as regards the postoperative complications. Functional outcome was satisfactory in both groups. Conclusion LISS achieves comparable results with ORIF in extra-articular fractures of the proximal tibia. Although LISS potentially has the radiation hazard, it reduces the perioperative complications with a shortened operation time and minimal soft tissue dissection.