[Influence of anterior fracture line on anterior cortical reduction loss after cephalomedullary nail fixation in intertrochanteric fractures].

Objective: To investigate the position of the anterior fracture line in AO/Orthopaedic Trauma Association (AO/OTA) type A2 unstable intertrochanteric fractures and its impact on the incidence of anterior cortical reduction loss after cephalomedullary nail fixation. Methods: A clinical data of 95 patients with intertrochanteric fractures who met the selection criteria between April 2020 and February 2023 was retrospectively analyzed. All patients were treated with cephalomedullary nail fixation, and the intra- and post-operative imaging data were complete. Among them, there were 37 males and 58 females. The age ranged from 61 to 97 years, with an average of 79.6 years. The time from injury to operation ranged from 7 hours to 11 days, with an average of 2.8 days. According to the 2018-AO/OTA classification standard, there were 39 cases of type 31-A2.2 and 56 cases of type 31-A2.3. Intraoperative fluoroscopy was used to record the number of patients with satisfactory fracture alignment. The preoperative CT data were imported into Mimics17.0 software to simulate the fracture reduction and measure the distance between the anterior fracture line and the intertrochanteric line bony ridge. The fractures were classified as transcapsular fractures, extra-capsular fractures, and intra-capsular fractures according to the distance. CT three-dimensional reconstruction was performed within 2 weeks after operation to observe the number of patients with anterior cortical reduction loss. The postoperative anterior cortical reduction loss incidence in patients with satisfactory fracture alignment, and the relationship between postoperative anterior cortical reduction loss and the position of the anterior fracture line were observed. Results: There were 52 cases (54.7%) of transcapsular fractures, 24 cases (25.3%) of extra-capsular fractures, and 19 cases (20.0%) of intra-capsular fractures. Among them, 41 of the 52 transcapsular fractures had satisfactory fracture alignment, and 4 (9.8%) of them experienced anterior cortical reduction loss after operation; 19 of the 24 extra-capsular fractures had satisfactory fracture alignment, and no anterior cortical reduction loss occurred; 16 of the 19 intra-capsular fractures had satisfactory fracture alignment, and 7 (43.8%) of them experienced anterior cortical reduction loss after operation. There was a significant difference in the incidence of anterior cortical reduction loss between groups ( χ 2=8.538， P=0.003). All patients were followed up 3-26 months (mean, 9 months). Among them, 91 cases had fracture healing, and 4 cases had nonunion. Conclusion: In AO/OTA type A2 unstable intertrochanteric fractures, where the anterior fracture line is located within the joint capsule, there is a high risk of anterior cortical reduction loss after operation.

Importance of the Posterior Plate in Three-Column Tibial Plateau Fractures: A Finite Element Analysis and Clinical Validation.

OBJECTIVE: Dual-plate fixation was thought to be the gold standard for treating complicated bicondylar tibial plateau fractures, yet it was found to be hard to accommodate the posterior column in three-column fractures. Currently, column-specific fixation is becoming more and more recognized, but no comprehensive investigation has been performed to back it up. Therefore, the objective of this study was to validate the importance of posterior column fixation in the three-column tibial fractures by a finite element (FE) analysis and clinical study. METHODS: In FE analysis, three models were developed: the longitudinal triple-plate group (LTPG), the oblique triple-plate group (OTPG), and the dual-plate group (DPG). Three loading scenarios were simulated. The distribution of the displacement and the equivalent von Mises stress (VMS) in each structure was calculated. The comparative measurements including the maximum posterior column collapse (MPCC), the maximum total displacement of the model (MTD), the maximum VMS of cortical posterior column (MPC-VMS), and the maximum VMS located on each group of plates and screws (MPS-VMS). The clinical study evaluated the indicators between the groups with or without the posterior plate, including operation time, blood loss volume, full-weight bearing period, Hospital for Special Surgery Knee Scoring system (HSS), Rasmussen score, and common postoperative complications. RESULTS: In the FE analysis, the MPCC, the MPC-VMS, and the MTD were detected in much lower amounts in LTPG and OTPG than in DPG. In comparison with DPG, the LTPG and OTPG had larger MPS-VMS. In the clinical study, 35 cases were included. In the triple-plate (14) and dual-plate (21) groups, the operation took 115.6 min and 100.5 min (p < 0.05), respectively. Blood loss in both groups was 287.0 mL and 206.6 mL (p < 0.05), and the full-weight bearing period was 14.5 weeks and 16.2 weeks (p < 0.05). At the final follow-up, the HSS score was 85.0 in the triple-plate group and 77.5 in the dual-plate (p < 0.05), the Rasmussen score was 24.1 and 21.6 (p < 0.05), there were two cases with reduction loss (9.5%) in the dual-plate group and one case of superficial incision infection found in the triple-plate group. CONCLUSION: The posterior implant was beneficial in optimizing the biomechanical stability and functional outcomes in the three-column tibial plateau fractures.

[Off target of distal interlocking screw in short cephalomedullary nail fixation for intertrochanteric femur fractures].

Objective: To analyze the causes and treatment of off target of the distal interlocking screws when short cephalomeduallry nails were installed through jig-guided targeting device, and to put forward the technical points to prevent off target. Methods: Retrospective analysis of 9 patients with intertrochanteric fractures treated between July 2014 and June 2023 was conducted, in which off target occurred during the insertion of the distal interlocking screw by jig-guided targeting device in short cephalomedullary nailling (<24 cm). There were 1 male and 8 females, with an average age of 82.7 years (range, 73-94 years). There were 3 cases of type A1, 5 cases of type A2, and 1 case of type A3 according to 2018-AO/Orthopaedic Trauma Association (AO/OTA) fracture classification. As for the misaligned distal interlocking screw, six parameters were collected and analyzed, including the time of finding, the position, the type of passing through the cortical bone, the special circumstances during operation (such as the need to remove the intramedullary nail for reaming the diaphysis, hammering, etc.), the treatment, and the patient follow-up results. Results: In the 9 patients, the off target of the distal interlocking screw was found in 7 cases during operation and in 2 cases after operation; the locking screw was located behind the nail in 7 cases and in front of the nail in 2 cases; the off target locking screw was passing tangentially in transcortical patern in 6 cases and in bicortical pattern through the medullary cavity in 3 cases. Three cases were attributed to the mismatch between the nail and the femur, two of which were attributed to the narrow femoral medullary cavity, one of which was attributed to the large anterolateral femoral bowing, and the other 6 cases were attributed to technical errors such as the loosening of the jig-guided targeting device, the tension of the fascia lata, and the blunt of the drill. In the 7 cases found during operation, the misaligned interlocking screw was removed first and the screw hole was left vacant, then in 2 cases, the interlocking screw was not used further; in 1 case, the distal dynamic hole was successfully inserted with a dynamic guide frame, and in 4 cases, the interlocking screw was successfully put after 2-3 attempts, leaving a large hole in the lateral cortex. No special treatment was performed in 2 cases found after operation. One patient was out of bed early after operation, 7 patients were in bed for 1 month, and 1 patient deteriorated to A3 type after operation and was in bed for 3 months. All the 9 patients were followed up 6-12 months, with an average of 8 months. Fracture healing was achieved in 8 patients. One patient with vacant interlocking screw had a secondary spiral fracture of the femoral shaft 3 months later, and was refixed with a long cephalomedullary nail and circlage wiring. Conclusion: Distal interlocking screw off target is rare, but when it occurs, it leaves a large cortical hole in the osteoporotic femoral shaft, reducing bone strength; the use of precision instruments and attention to technical details can reduce this adverse phenomenon.

[Research progress on valgus impacted proximal humeral fractures].

Objective: To review the advancement made in the understanding of valgus impacted proximal humeral fracture (PHF). Methods: The domestic and foreign literature about the valgus impacted PHF was extensively reviewed and the definition, classification, pathological features, and treatment of valgus impacted PHFs were summarized. Results: PHF with a neck shaft angle ≥160° is recognized as a valgus impacted PHF characterized by the preservation of the medial epiphyseal region of the humeral head, which contributes to maintenance of the medial periosteum's integrity after fracture and reduces the occurrence of avascular necrosis. Therefore, the valgus impacted PHF has a better prognosis when compared to other complex PHFs. The Neer classification designates it as a three- or four-part fracture, while the AO/Association for the Study of Internal Fixation (AO/ASIF) categorizes it as type C (C1.1). In the management of the valgus impacted PHF, the selection between conservative and surgical approaches is contingent upon the patient's age and the extent of fracture displacement. While conservative treatment offers the advantage of being non-invasive, it is accompanied by limitations such as the inability to achieve anatomical reduction and the potential for multiple complications. Surgical treatment includes open reduction combined with steel wire or locking plate and/or non-absorbable suture, transosseous suture technology, and shoulder replacement. Surgeons must adopt personalized treatment strategies for each patient with a valgus impacted PHF. Minimally invasive surgery helps to preserve blood supply to the humeral head, mitigate the likelihood of avascular necrosis, and reduce postoperative complications of bone and soft tissue. For elderly patients with severe comminuted and displaced fractures, osteoporosis, and unsuitable internal fixation, shoulder joint replacement is the best treatment option. Conclusion: Currently, there has been some advancement in the classification, vascular supply, and management of valgus impacted PHF. Nevertheless, further research is imperative to assess the clinical safety, biomechanical stability, and indication of minimally invasive technology.

Morphological characteristics and a new classification system of the inferior pole fracture of the patella: A computer-tomography-based study.

PURPOSE: The objective of this study was to measure the morphological characteristics of inferior pole fracture of the patella (IPFP) and develop a practical classification system to determine the corresponding treatment protocols for different IPFPs with specific patterns. METHODS: A retrospective radiographic review was performed on a series of 71 patients with IPFP. The preoperative CT data were collected and measured using image processing software. The number of fragments, maximum fracture fragment anteroposterior length (MFFAL), maximum fracture fragment transverse length (MFFTL), fracture fragment coronal angle (FFCA), fracture fragment sagittal angle (FFSA), maximum fracture fragment height (MFFH) and maximum transverse sectional area (MTSA) were analysed. RESULTS: The mean number of fracture fragments was 3.8. The average MFFAL was 14.9 mm, the average MFFTL was 23.5 mm, the average FFCA was 92.1°, the average FFSA was 93.0°, the average MFFH was 13.6 mm, and the average MTSA was 299.3 mm2. A new classification system was introduced to describe the varied patterns of IPFP, summarized as (I) simple IPFP; (II) comminuted IPFP; (III) simple IPFP with simple patellar body fracture; and (IV) comminuted patellar fracture involving the inferior pole. With the four-type classification system, 12 type I, 22 type II, 21 type III, and 16 type IV lesions were observed, each with specific morphological characteristics. CONCLUSION: Most IPFPs exhibited a diversiform pattern, demonstrating that coverage fixation was likely needed. The four-type classification system might offer a valuable approach to help orthopaedic surgeons make individual treatment plans.

The remnant axial cortical length of the proximal femur in pertrochanteric fractures: a three-dimensional computed tomography study and its clinical implications.

BACKGROUND: Cortical buttress are important factors for postoperative stable reconstruction of per/inter-trochanteric fractures. The study aimed to measure the remnant axial cortical length (RACL) of the proximal circumference of the femur, and to determine which part of the RACL can be used reliably to postoperatively sustain the head-neck fragment as a cortical support pattern. METHODS: Eighty patients with trochanteric hip fractures admitted from January 2015 to January 2016 were included in a retrospective study. Their pre-operative computed tomography (CT) images were used to form 3D-CT reconstructions via Mimics software. After simulated rotation and movement for fracture reduction, the RACL, its three component parts-namely, the remnant anterior cortex (RAC), remnant lateral cortex (RLC), and remnant posterior cortex (RPC) -the γ angle between the anterior and posterior cortex, and the Hsu's lateral wall thickness (LWT) were evaluated. RESULTS: Patients with an A1 fracture (21/80) had a longer RACL (88.8 ± 15.8 mm) than those with an A2 fracture (60.0 ± 11.9 mm; P < 0.01). The RAC, RLC, and RPC of the RACL in A1 fractures were also significantly longer than those in A2 fractures (P < 0.001). However, the most significant difference among the three components of the RACL was in the RPC, which was 27.3 ± 7.8 mm in A1 fractures and 9.2 ± 6.6 mm in A2 fractures. In addition, the coefficient of variation of the RAC was only 20.0%, while that of the RPC was 75.5%. The average γ angle in A1 fractures was 16.2 ± 13.1°, which was significantly smaller than that in A2 fractures, which was 40.3 ± 14.5° (P < 0.001). There was a significant statistical difference in the LWT between A1 and A2 fractures (P < 0.001). There were significant differences in the RACL, RAC, RLC, RPC, γ angle, and LWT among the five subtypes (P < 0.001). CONCLUSIONS: The RAC is relatively stable in pertrochanteric fractures. Fracture reduction through a RAC buttress may help to enhance the postoperative stable reconstruction of per/inter-trochanteric fractures and make possible good mechanical support for fracture healing.

Positive medial cortical support versus anatomical reduction for trochanteric hip fractures: Finite element analysis and biomechanical testing.

BACKGROUND AND OBJECTIVES: The anatomical reduction (AR) is usually considered the best option for fractures. Nevertheless, in unstable trochanteric hip fractures (UTHF), previous clinical reports found that the positive medial cortical support (PMCS, an over-reduction technique) attained higher mechanical stability, but this challenging clinical finding still needs experimental validation. METHODS: This study constructed in-silico and biomechanical PMCS and AR models, with the use of the most clinically-representative geometry design of fracture models, the multi-directional design in FE analysis, and the subject-specific (osteoporotic) bone material properties, to make the models better mimic the actual condition in clinical settings. Then multiple performance variables (von-Mises stress, strain, integral axial stiffness, displacement, structural changes, etc.) were assessed to uncover details of integral and regional stability. RESULTS: Among in-silico comparison, PMCS models showed significantly lower maximum displacement than AR models, and the maximum von Mises stress of implants (MVMS-I) was significantly lower in PMCS models than in AR models (highest MVMS-I in -30°-A3-AR of 1055.80 ± 93.37 MPa). Besides, PMCS models had significantly lower maximum von Mises stress along fracture surfaces (MVMS-F) (highest MVMS-F in 30°-A2-AR of 416.40 ± 38.01 MPa). Among biomechanical testing comparison, PMCS models showed significantly lower axial displacement. Significantly lower change of neck-shaft angle (CNSA) was observed in A2-PMCS models. A fair amount of AR models converted into the obvious negative medial cortical support (NMCS) condition, whereas all PMCS models kept the PMCS condition. The results were also validated through comparison to previous clinical data. CONCLUSIONS: The PMCS is superior to the AR in the UTHF surgery. The current study opens up the second thought of the role of over-reduction technique in bone surgery.

A new posterosuperior screw placement strategy to avoid in-out-in screws in femoral neck fractures.

Objective: The inverted triangle configuration of the three cannulated screws is the classic fixation method most commonly performed for undisplaced femoral neck fractures in young and geriatric patients. However, the posterosuperior screw has a high incidence of cortical breach, known as an in-out-in (IOI) screw. In this study, we present a novel posterosuperior screw placement strategy to prevent the screw from becoming IOI. Methods: Using computed tomography data and image-processing software, 91 undisplaced femoral neck fractures were reconstructed. The anteroposterior (AP), lateral, and axial radiographs were simulated. To simulate the intraoperative screw placement process, participants used three screw insertion angles (0°, 10°, and 20°) to place the screw on the AP and lateral views of the radiograph according to the three established strategies. On the AP radiograph, a screw was placed abutting (strategy 1), 3.25 mm away from (strategy 2), or 6.5 mm away from (strategy 3) the superior border of the femoral neck. On the lateral radiograph, all the screws were placed abutting the posterior border of the femoral neck. Axial radiographs were used to evaluate the screw position. Results: In strategy 1, all the placed screws were IOI regardless of the screw insertion angle. In strategy 2, 48.3% (44/91) of IOI screws occurred at a 0° screw insertion angle, 41.7% (38/91) of IOI screws occurred at a 10° screw insertion angle, and 42.9% (39/91) of IOI screws occurred at a 20° screw insertion angle situation. In strategy 3, no IOI screw occurred, and the screw insertion angles did not affect the safety and accuracy of screw placement. Conclusions: Screws placed according to strategy 3 are safe. The reliability of this screw placement strategy is unaffected by a screw insertion angle of less than 20 degrees.

[Finite element study of three novel internal fixation modes for bicondylar four-quadrant fractures of tibial plateau].

Objective: To compare the biomechanical differences among the three novel internal fixation modes in treatment of bicondylar four-quadrant fractures of the tibial plateau through finite-element technique, and find an internal fixation modes which was the most consistent with mechanical principles. Methods: Based on the CT image data of the tibial plateau of a healthy male volunteer, a bicondylar four-quadrant fracture model of the tibial plateau and three experimental internal fixation modes were established by using finite element analysis software. The anterolateral tibial plateaus of groups A, B, and C were fixed with inverted L-shaped anatomic locking plates. In group A, the anteromedial and posteromedial plateaus were longitudinally fixed with reconstruction plates, and the posterolateral plateau was obliquely fixed with reconstruction plate. In groups B and C, the medial proximal tibia was fixed with T-shaped plate, and the posteromedial plateau was longitudinally fixed with the reconstruction plate or posterolateral plateau was obliquely fixed with the reconstruction plate, respectively. An axial load of 1 200 N was applied to the tibial plateau (a simulation of a 60 kg adult walking with physiological gait), and the maximum displacement of fracture and maximum Von-Mises stress of the tibia, implants, and fracture line were calculated in 3 groups. Results: Finite element analysis showed that the stress concentration area of tibia in each group was distributed at the intersection between the fracture line and screw thread, and the stress concentration area of the implant was distributed at the joint of screws and the fracture fragments. When axial load of 1 200 N was applied, the maximum displacement of fracture fragments in the 3 groups was similar, and group A had the largest displacement (0.74 mm) and group B had the smallest displacement (0.65 mm). The maximum Von-Mises stress of implant in group C was the smallest (95.49 MPa), while that in group B was the largest (177.96 MPa). The maximum Von-Mises stress of tibia in group C was the smallest (43.35 MPa), and that in group B was the largest (120.50 MPa). The maximum Von-Mises stress of fracture line in group A was the smallest (42.60 MPa), and that in group B was the largest (120.50 MPa). Conclusion: For the bicondylar four-quadrant fracture of the tibial plateau, a T-shaped plate fixed in medial tibial plateau has a stronger supporting effect than the use of two reconstruction plates fixed in the anteromedial and posteromedial plateaus, which should be served as the main plate. The reconstruction plate, which plays an auxiliary role, is easier to achieve anti-glide effect when it is longitudinally fixed in posteromedial plateau than obliquely fixed in posterolateral plateau, which contributes to the establishment of a more stable biomechanical structure.

Residual lateral wall width predicts a high risk of mechanical complications in cephalomedullary nail fixation of intertrochanteric fractures: a retrospective cohort study with propensity score matching.

PURPOSE: The purpose of this study is to determine whether the integrity of the entry portal of head-neck implant is related to postoperative mechanical complications. METHODS: We retrospectively reviewed consecutive patients with pertrochanteric fractures in our hospital treated from January 1, 2018, to September 1, 2021. Based on the integrity of the entry portal for head-neck implants on the femoral lateral wall, patients were divided into two groups, including the ruptured entry portal (REP) group and the intact entry portal (IEP) group. After 4:1 propensity score-matched analyses were used to balance the baseline of the two groups, a total of 55 patients were extracted from the original participants, including 11 patients in the REP group and 44 matched patients in the IEP group. The anterior to posterior cortex width on the mid-level of the lesser trochanter was measured and defined as the residual lateral wall width (RLWW). RESULTS: Compared with the IEP group, the REP group was correlated with postoperative mechanical complications (OR = 12.00, 95% CI 1.837-78.369, P = 0.002) and hip-thigh pain (OR = 26.67, 95% CI 4.98-142.86). RLWW ≤ 18.55 mm indicated a high likelihood (tau-y = 0.583, P = 0.000) of becoming the REP type postoperatively and being more likely to suffer from mechanical complications (OR = 30.67, 95% CI 3.91-240.70, P = 0.000) and hip-thigh pain (OR = 14.64, 95% CI 2.36-90.85, P = 0.001). CONCLUSION: Rupture of entry portal is a high-risk factor for mechanical complications in intertrochanteric fractures. RLWW ≤ 18.55 mm is a reliable predictor of the postoperative REP type.

Insufficient proximal medullary filling of cephalomedullary nails in intertrochanteric femur fractures predicts excessive postoperative sliding: a case-control study.

OBJECTIVE: Excessive postoperative sliding is a common complication of intramedullary nails in the treatment of intertrochanteric femur fractures. The aim of this study was to identify risk factors for excessive postoperative sliding in the intertrochanteric fractures treated with an intramedullary nail. METHODS: A retrospective analysis of 369 patients with femoral intertrochanteric fractures treated with short intramedullary nails between February 2017 and September 2020 was performed. Patients were classified into an excessive sliding group (ES group) and a control group according to the sliding distance after 6 months of follow-up. The proximal medullary filling degree (MFD), fracture reduction patterns in the anteroposterior (AP) view and lateral view, and tip-apex distance (TAD) were evaluated and compared in each group. RESULTS: Thirty-three cases were included in the ES group, and 336 cases were included in the control group. No significant differences in age, sex, fracture side, AO Foundation and Orthopaedic Trauma Association (AO/OTA) classification, Dorr classification, Singh Osteoporosis Index (SOI), American Society of Anesthesiologists classification (ASA), TAD or fracture reduction patterns in the AP view were noted between the two groups. The negative reduction pattern can strongly predict excessive postoperative sliding (OR 4.286, 95% CI 1.637-11.216, P = 0.003). The incidence of excessive postoperative sliding increased by 8.713-fold when the MFD decreased by 10% (OR 8.713, 95% CI 1.925-39.437, P = 0.005). CONCLUSIONS: A low medullary filling degree and negative fracture reduction pattern in the lateral view were both independent risk factors for excessive postoperative sliding.

Tension-band wiring through a single cannulated screw combined with suture anchors to treat inferior pole fracture of the patella.

PURPOSE: To evaluate the feasibility and clinical outcomes of tension-band wiring through a single cannulated screw combined with two suture anchors in treating inferior pole fracture of the patella. METHODS: Between September 2018 and September 2021, a total of 22 patients with a mean age of 55 years who sustained inferior pole fracture of the patella and were treated by tension-band wiring through a single cannulated screw combined with two suture anchors were enrolled. X-ray radiographs were performed to observe the bone union time. The duration of each operation was recorded to reflect the complexity of surgical treatment. Functional measurements, comprising range of motion (ROM), the Böstman scale, and the Knee Injury and Osteoarthritis Outcome Score (KOOS), were taken. Postoperative complications including fixation failure, incision infection, loss of reduction, and malunion were evaluated. RESULTS: All patients were followed up for an average of 17 months (range: 12-25 months). The average clinical bone union time was 8 weeks (range: 6-12 weeks), and the radiographic bone union time was 11 weeks (range: 8-12 weeks). At the final follow-up, the mean ROM was 136° (range: 115°-140°), the KOOS was 85 (range: 68-100) and the Böstman score was 28 (range: 20-30); these outcomes were classified as excellent in 17 cases and good in 5 cases, with no instances of poor results. Loss of reduction occurred in one case, while no cases of incision infection, fixation failure or malunion were observed. CONCLUSION: For inferior pole fracture of the patella, tension-band wiring through a single cannulated screw combined with suture anchors can offer sufficient fixation stability to achieve a satisfactory clinical outcome with reduced operational complexity; this procedure should be recommended in clinical practice.

Two-Part Intertrochanteric Femur Fractures with Bisection of the Lesser Trochanter: An Irreducible Fracture Pattern.

Objective: To introduce the clinical features of and surgical techniques for a rare type of irreducible pertrochanteric femur fracture pattern with bisection of the lesser trochanter. Methods: From January 2017 to December 2019, 357 patients with per/intertrochanteric femur fractures underwent surgery by closed reduction and internal fixation, of whom 12 patients were identified with rare preoperative imaging features, the lesser trochanter was almost equally bisected. The main fracture pathoanatomy of these cases included: The anterior fracture line passed along the intertrochanteric line to the medial lesser trochanter and bisected it into 2 equal parts from mid-level of the lesser trochanteric protrusion. The proximal part of the lesser trochanter connected to the head-neck fragment and attached by the psoas major tendon, while the distal part of the lesser trochanter connected to the femoral shaft and attached by the tendon of the iliac muscle. These fractures were irreducible by a closed maneuver and were reduced with limited assistance by some devices, and short intramedullary nails were used for fixation of these fractures. Results: All patients were followed up for an average of 14.2 ± 2.1 months. Clinical fracture union occurred at an average of 10.8 ± 1.5 weeks, while radiographic union occurred at an average of 12.7 ± 1.2 weeks. No cut out of the helical blade was visible on radiographs. The average Parker-Palmer score was 6.9 ± 1.3 (range, 5-9) at the last follow up, including 8 cases rated as excellent, 2 as good and 2 as fair. Conclusion: Two-part pertrochanteric femur fractures with bisection of the lesser trochanter have an irreducible fracture pattern with cortical locking and soft tissue incarceration. Soft tissue release and short cephalomedullary nail fixation for this fracture pattern provide stable fixation and allow early exercise. This treatment appears to have excellent outcomes in the short and medium terms.

[Progress in surgical treatment of inferior patellar pole fractures].

Objective: To summarize the surgical treatment methods and progress of inferior patellar pole fractures and provide reference for clinical application. Methods: The literature on surgical treatment of inferior patellar pole fractures was extensively reviewed, and the relevant research progress, advantages, and limitations were summarized. Results: The inferior pole of the patella is an important part of the knee extension device, which can strengthen the force arm of the quadriceps. Inferior patellar pole fractures are relatively rare and often comminuted, usually requiring surgical treatment. At present, there are various methods to treat inferior patellar pole fractures, including patellectomy of inferior pole, tension-band wiring technique, plate internal fixation, suture anchor fixation, claw-like shape memory alloy, separate vertical wiring technique. Different methods have their own characteristics, advantages, and disadvantages. The single internal fixation method has more complications and is easy to cause fixation failure. Therefore, the trend of combining various internal fixation methods is developing at present. Conclusion: When the main fragment of the inferior patellar pole fracture is large and mainly distributed transversely, the combination protocol based on tension-band wiring technique can be regarded as an ideal choice. When the fragments are severely damaged and small, the comprehensive protocol based on suture fixation can result in a better postoperative functional recovery.

[Proposal of a novel comprehensive classification for femoral intertrochanteric fractures].

Objective: To introduce a novel comprehensive classification for femoral intertrochanteric fractures, and to accommodate the clinical requirement for the world-wide outbreak of geriatric hip fractures and surgical operations. Methods: On the basis of reviewing the history of classification of femoral intertrochanteric fractures and analyzing the advantages and disadvantages of AO/Orthopaedic Trauma Association (AO/OTA) classification in different periods, combined with the current situation of extensive preoperative CT scan and three-dimensional reconstruction and widespread use of intramedullary nail fixation in China, the "Elderly Hip Fracture" Research Group of the Reparative and Reconstructive Surgery Committee of the Chinese Rehabilitation Medical Association proposed a novel comprehensive classification for femoral intertrochanteric fractures, focusing on the structure of fracture stability reconstruction during internal fixation. Results: The novel comprehensive classification of femoral intertrochanteric fractures incorporates multiple indicators of fracture classification, including the orientation of the fracture line, the degree of fracture fragmentation, the lesser trochanteric bone fragment and its distal extension length (>2 cm), the posterior coronal bone fragment and its anterior extension width (involving the lateral cortex of the head and neck implant entry point), transverse fracture of the lateral and anterior wall and its relationship with the implant entry point in the head and neck, and whether the cortex of the anteromedial inferior corner can be directly reduced to contact, etc. The femoral intertrochanteric fractures are divided into 4 types (type A1 is simple two-part fractures, type A2 is characterized by lesser trochanter fragment and posterior coronal fractures, type A3 is reverse obliquity and transverse fractures, type A4 is medial comminution which lacks anteromedial cortex transmission of compression force), each of which is subdivided into 4 subtypes and further subdivide into finer subgroups. In a review of 550 trochanteric hip fracture cases by three-dimensional CT, type A1 accounted for 20.0%, type A2 for 62.5%, type A3 for 15.5%, and type A4 for 2.0%, respectively. For subtypes, A2.2 is with a "banana-like" posterior coronal fragment, A2.4 is with distal cortex extension >2 cm of the lesser trochanter and anterior cortical expansion of the posterior coronal fragment to the entry portal of head-neck implants, A3.4 is a primary pantrochanteric fracture, and A4.4 is a concomitant ipsilateral segmental fracture of the neck and trochanter region. Conclusion: The novel comprehensive classification of femoral intertrochanteric fractures can describe the morphological characteristics of fractures in more detail, include more rare and complex types, provide more personalized subtype selection, and adapt to the clinical needs of both fractures and surgeries.

[Three-dimensional finite element analysis of exo-cortical placement of humeral calcar screw for reconstruction of medial column stability].

Objective: To explore the biomechanical stability of the medial column reconstructed with the exo-cortical placement of humeral calcar screw by three-dimensional finite element analysis. Methods: A 70-year-old female volunteer was selected for CT scan of the proximal humerus, and a wedge osteotomy was performed 5 mm medially inferior to the humeral head to form a three-dimensional finite element model of a 5 mm defect in the medial cortex. Then, the proximal humeral locking plate (PHILOS) was placed. According to distribution of 2 calcar screws, the study were divided into 3 groups: group A, in which 2 calcar screws were inserted into the lower quadrant of the humeral head in the normal direction for supporting the humeral head; group B, in which 1 calcar screw was inserted outside the cortex below the humeral head, and the other was inserted into the humeral head in the normal direction; group C, in which 2 calcar screws were inserted outside the cortex below the humeral head. The models were loaded with axial, shear, and rotational loadings, and the biomechanical stability of the 3 groups was compared by evaluating the peak von mises stress (PVMS) of the proximal humerus and the internal fixator, proximal humeral displacement, neck-shaft angle changes, and the rotational stability of the proximal humerus. Seven cases of proximal humeral fractures with comminuted medial cortex were retrospectively analyzed between January 2017 and December 2020. Locking proximal humeral plate surgery was performed, and one (5 cases) or two (2 cases) calcar screws were inserted into the inferior cortex of the humeral head during the operation, and the effectiveness was observed. Results: Under axial and shear force, the PVMS of the proximal humerus in group B and group C was greater than that in group A, the PVMS of the internal fixator in group B and group C was less than that in group A, while the PVMS of the proximal humerus and internal fixator between group B and group C were similar. The displacement of the proximal humerus and the neck-shaft angle change among the 3 groups were similar under axial and shear force, respectively. Under the rotational torque, compared with group A, the rotation angle of humerus in group B and group C increased slightly, and the rotation stability decreased slightly. All the 7 patients were followed up 6-12 months. All the fractures healed, and the healing time was 8-14 weeks, with an average of 10.9 weeks; the neck-shaft angle changes (the difference between the last follow-up and the immediate postoperative neck-shaft angle) was (1.30±0.42)°, and the Constant score of shoulder joint function was 87.4±4.2; there was no complication such as humeral head varus collapse and screw penetrating the articular surface. Conclusion: For proximal humeral fractures with comminuted medial cortex, exo-cortical placement of 1 or 2 humeral calcar screw of the locking plate outside the inferior cortex of the humeral head can also effectively reconstruct medial column stability, providing an alternative approach for clinical practice.

Surgical exposure to posterolateral quadrant tibial plateau fractures: an anatomic comparison of posterolateral and posteromedial approaches.

BACKGROUND: Management of posterolateral tibial plateau quadrant fractures can be challenging, and two posterior approaches were frequently used for exposure, reduction, and fixation: posterolateral approach and posteromedial approach. The purpose of this study was to compare their deep anatomical structure and analyze their limits and the risk of injury to important structures during surgical dissection of two approaches. METHOD: Five lower limb specimens were used in this study. After dissection of the skin and superficial fascia of each specimen, deep structures were dissected via posteromedial and posterolateral approach, and several parameters including perpendicular distance from the anterior tibial artery coursing through the interosseous membrane fissure to the lateral joint line and apex of fibular head and so on were measured and analyzed. RESULT: The perpendicular distance from the ATA coursing through the interosseous membrane fissure to the lateral joint line was 49.3 ± 5.6 mm (range 41.3-56.7 mm), while the distance to the apex of fibular head was 37.7 ± 7.2 mm (range 29.0-48.0 mm). The transverse distance of the anterior tibial vascular bundle is around 10 mm. The perpendicular distance from the top accompanying vein of the ATA bundle to lateral joint line and apex of fibular head was 44.1 ± 6.3 mm and 32.5 ± 7.6 mm, respectively. The maximum proportion of posterolateral tibial plateau shielded by the fibular head from the posterior view was 61.7 ± 4.9% (range 55.6-64.1%). The average length of popliteus muscle outside the joint was 83.1 ± 6.0 mm (range 76.5-92.2 mm), and the width in the middle was 28.1 ± 4.3 mm (range 26.6-29.1 mm). CONCLUSION: Although posterolateral approach seems more direct for exposure of posterolateral quadrant tibial plateau fracture, it has three major disadvantages in deep dissection. Posteromedial approach through the medial board of medial head of gastrocnemius-soleus may be safer, but it was hard for direct visualization of articular surface which limits it usage for only a few cases.

Calcar fracture gapping: a reliable predictor of anteromedial cortical support failure after cephalomedullary nailing for pertrochanteric femur fractures.

BACKGROUND: Maintaining anteromedial cortical support is essential for controlling sliding and decreasing postoperative implant-related complications. However, adequate fracture reduction with cortical support in immediate postoperative fluoroscopy is not invariable in postoperative follow-ups. This study was conducted to investigate the risk factors leading to anteromedial cortical support failure in follow up for pertrochanteric femur fractures treated with cephalomedullary nails. METHODS: This retrospective study enrolled 159 patients with pertrochanteric fractures (AO/OTA- 31A1 and 31A2) that fixed with cephalomedullary nails. All patients were evaluated as adequate fracture reduction in immediate postoperative fluoroscopy before leaving the operation theater. The patients were separated into two groups based on the condition of the anteromedial cortex in the postoperative 3D CT with full-range observation: those with calcar support maintained in Group 1 and those with calcar support lost in Group 2. Demographic information, fracture classification, TAD (tip-apex distance), Cal-TAD, Parker ratio, NSA (neck-shaft angle), reduction quality score, and calcar fracture gapping were collected and compared. Logistic regression analysis was conducted to explore the risk factors leading to anteromedial cortex change. RESULTS: Anteromedial cortical support failure was noted in 46 cases (29%). There was no significant difference between the two groups concerning age, sex, side injury, TAD, Cal-TAD, Parker ratio, or NSA. There was a significant difference in the AO/OTA fracture classification in univariate analysis but no difference in the multivariable analysis. The reduction quality score, calcar fracture gapping in the AP (anteroposterior), and lateral views were significantly associated with anteromedial cortical support failure in follow-up after cephalomedullary nailing in the multivariable analysis. The threshold value of calcar fracture gapping for the risk of loss was 4.2 mm in the AP and 3.8 mm in the lateral fluoroscopies. Mechanical complications (lateral sliding and varus) were frequently observed in the negative anteromedial cortical support group. CONCLUSIONS: Good reduction quality was a protective factor, and larger calcar fracture gapping in the AP and lateral views were risk factors leading to the postoperative loss of anteromedial cortical support. Therefore, we should pay close attention to fracture reduction and minimize the calcar fracture gap during surgery.

Low filling ratio of the distal nail segment to the medullary canal is a risk factor for loss of anteromedial cortical support: a case control study.

BACKGROUND: Anteromedial cortical support apposition (positive and/or neutral cortical relations) is crucial for surgical stability reconstruction in the treatment of trochanteric femur fractures. However, the loss of fracture reduction is frequent in follow-ups after cephalomedullary nail fixation. This paper aimed to investigate the possible predictive risk factors for postoperative loss of anteromedial cortex buttress after nail fixation. METHODS: A retrospective analysis of 122 patients with AO/OTA 31A1 and A2 trochanteric femur fractures treated with cephalomedullary nails between January 2017 and December 2019 was performed. The patients were classified into two groups according to the postoperative status of the anteromedial cortical apposition in 3D CT images: Group 1 with contact "yes" (positive or anatomic) and Group 2 with contact "No" (negative, loss of contact). The fracture reduction quality score, tip-apex distance (TAD), calcar-referenced TAD (Cal-TAD), Parker ratio, neck-shaft angle (NSA), and the filling ratio of the distal nail segment to medullary canal diameter in anteroposterior (AP) and lateral fluoroscopies (taken immediately after the operation) were examined in univariate and multivariate analyses. Mechanical complications were measured and compared in follow-up radiographs. RESULTS: According to the postoperative 3D CT, 84 individuals (69%) were categorized into Group 1, and 38 individuals (31%) were classified as Group 2. The multivariate logistic regression analysis showed that the poor fracture reduction quality score (P < 0.001) and decreasing filling ratio in the lateral view (P < 0.001) were significant risk factors for the loss of anteromedial cortical contact. The threshold value for the distal nail filling ratio in lateral fluoroscopy predicting fracture reduction re-displacement was found to be 53%, with 89.3% sensitivity and 78.9% specificity. The mechanical complication (varus and over lateral sliding) rate was higher in Group 2. CONCLUSIONS: The fracture reduction quality score and the decreasing filling ratio of the distal nail to the medullary canal in the lateral view (a novel parameter causing pendulum-like movement of the nail) were possible risk factors for postoperative loss of anteromedial cortical support.

Sub-Classification of AO/OTA-2018 Pertrochanteric Fractures Is Associated With Clinical Outcomes After Fixation of Intramedullary Nails.

BACKGROUND: The new edited AO/OTA-2018 classification of pertrochanteric fractures was revised and no longer based on the status of lesser trochanter. This paper aimed to explore the clinical and technical outcomes among the subgroups (31A1 and 31A2) of the new classification treated with cephalomedullary nails. METHODS: A retrospective research of 154 patients diagnosed with pertrochanteric fractures (AO/OTA-2018 31A1.2/3 and 31A2.1/2/3) treated with intramedullary nails was conducted. The baseline data and outcomes were compared among the subgroups. The outcomes included tip-apex distance (TAD), Cal-TAD, Parker ratio, neck shaft angle (NSA), blood loss, varus displacement, and over lateral sliding rate of the blade. RESULTS: There were 154 cases involving 48 males and 106 females. The average age was higher in the sub-classifications of A2.2 and A2.3 than A1.2. Furthermore, the subgroups of A2.2 and A2.3 presented inferior outcomes with regard to blood loss and reduction quality score than A1.2 and A1.3. The subgroup of A2.3 was further poor with respect to calcar fracture gapping in the anteroposterior view and excessive lateral migration occurrence rate than A1.2. CONCLUSIONS: Complex pertrochanteric fractures indicated inferior outcomes compared to simple sub-classifications, which might lead by the incompetent of lateral wall and instability of the fracture. The newly proposed AO/OTA-2018 classification was conductive to forecast the prognosis.