Clinical Analysis of Single and Double Sacroiliac Screws in the Treatment of Tile C1 Pelvic Fracture

We investigated the difference between fixation of single and double sacroiliac screws in the treatment of Tile C1 pelvic fractures. The data of 54 patients with Tile C1 pelvic fractures who were admitted to the trauma center of the Red Society Hospital Affiliated to Xi’an Jiaotong University between August 2016 and August 2020 were retrospectively analyzed. All patients with posterior pelvic ring injuries underwent fixation with sacroiliac screws assisted by a percutaneous robotic navigation system. The operative time, amount of intraoperative blood loss, and postoperative follow-up time between the two groups (single sacroiliac and double sacroiliac screw groups) were compared. The Matta and Majeed scores at the last follow-up were compared between the groups to evaluate fracture reduction and functional recovery. Forty-nine patients were followed up for 17.2 (±4.5) months and 16.2 (±3.4) months in the single and double sacroiliac screw groups, respectively. All patients had excellent fracture reduction immediately after surgery, according to the Matta score. All fractures healed without complications. There was no statistically significant difference in preoperative general information, amount intraoperative blood loss, intraoperative anterior ring fixation method, and postoperative follow-up time between the two groups ( P > 0.05 ). The operative time of the single sacroiliac screw group was shorter than that of the double sacroiliac screw group ( P < 0.05 ). At the last follow-up, the Matta score of the double sacroiliac screw group was significantly better than that of the single sacroiliac screw group ( P < 0.05 ), and there was no statistically significant difference in the Majeed functional scores ( P > 0.05 ). For Tile C1 pelvic fractures, double sacroiliac screw fixation of posterior ring injuries can provide a more stable treatment with no statistically significant difference in functional recovery.

Is cement-augmented sacroiliac screw fixation with partially threaded screws superior to that with fully threaded screws concerning compression and pull-out force in fragility fractures of the sacrum? – a biomechanical analysis

Background Providing a stable osteosynthesis in fragility fractures of the pelvis can be challenging. Cement augmentation increases screw fixation in osteoporotic bone. Generating interfragmentary compression by using a lag screw also improves the stability. However, it is not known if interfragmentary compression can be achieved in osteoporotic sacral bone by cement augmentation of lag screws. The purpose of this study was to compare cement-augmented sacroiliac screw osteosynthesis using partially versus fully threaded screws in osteoporotic hemipelvises concerning compression of fracture gap and pull-out force. Methods Nine fresh-frozen human cadaveric pelvises with osteoporosis were used. In all specimens, one side was treated with an augmented fully threaded screw (group A), and the other side with an augmented partially threaded screw (group B) after generating a vertical osteotomy on both sides of each sacrum. Afterwards, first a compression test with fracture gap measurement after tightening of the screws was performed, followed by an axial pull-out test measuring the maximum pull-out force of the screws. Results The fracture gap was significantly wider in group A (mean: 1.90 mm; SD: 1.64) than in group B (mean: 0.91 mm; SD: 1.03; p = 0.028). Pull-out force was higher in group A (mean: 1696 N; SD: 1452) than in group B (mean: 1616 N; SD: 824), but this difference was not statistically significant (p = 0.767). Conclusions Cement augmentation of partially threaded screws in sacroiliac screw fixation allows narrowing of the fracture gap even in osteoporotic bone, while resistance against pull-out force is not significantly lower in partially threaded screws compared to fully threaded screws.

Effects of different pedicle screw insertion depths on sagittal balance of lumbar degenerative spondylolisthesis, a retrospective comparative study

Background Few reports to date have evaluated the effects of different pedicle screw insertion depths on sagittal balance and prognosis after posterior lumbar interbody and fusion (PLIF) in patients with lumbar degenerative spondylolisthesis (LDS). Methods A total of 88 patients with single-level PLIF for LDS from January 2018 to December 2019 were enrolled. Long screw group (Group L): 52 patients underwent long pedicle screw fixation (the leading edge of the screw exceeded 80% of the anteroposterior diameter of vertebral body). Short screw group (Group S): 36 patients underwent short pedicle screw fixation (the leading edge of the screw was less than 60% of the anteroposterior diameter of vertebral body). Local deformity parameters of spondylolisthesis including slip degree (SD) and segment lordosis (SL), spino-pelvic sagittal plane parameters including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and lumbar lordosis (LL), Oswestry Disability Index (ODI), and Visual Analog Scale (VAS) for back pain of both groups were compared. Postoperative complications, including vertebral fusion rate and screw loosening rate, were recorded. Results Except that PI in Group S at the final follow-up was not statistically different from the preoperative value (P > 0.05), other parameters were significantly improved compared with preoperative values one month after surgery and at the final follow-up (P < 0.05). There was no significant difference in parameters between Group L and Group S before and one month after surgery (P > 0.05). At the final follow-up, SD, SL, LL, PT and PI-LL differed significantly between the two groups (P < 0.05). Compared with the preoperative results, ODI and VAS in both groups decreased significantly one month after surgery and at the final follow-up (P < 0.05). Significant differences of ODI and VAS were found between the two groups at the final follow-up (P < 0.05). Postoperative complications were not statistically significant between the two groups (P > 0.05). Conclusions PLIF can significantly improve the prognosis of patients with LDS. In terms of outcomes with an average follow-up time of 2 years, the deeper the screw depth is within the safe range, the better the spino-pelvic sagittal balance may be restored and the better the quality of life may be.

Efficacy Comparison of Three Kinds of Distal Tibial Hemiepiphyseal Implants in the Treatment of Postoperative Ankle Valgus of Congenital Pseudarthrosis of the Tibia

Background: Congenital pseudarthrosis of the tibia is a complex and serious disease in orthopedics which often requires multiple operations for treatment. Postoperative ankle valgus deformity is easily seen after the operation of congenital pseudarthrosis of the tibia. The aim of this study is to retrospectively evaluate the safety of three different implants for treating postoperative ankle valgus after congenital pseudarthrosis of the tibia.Methods: A total of 41 patients with postoperative ankle valgus after congenital pseudarthrosis of the tibia from December 2010 to July 2019 were selected. Out of these 41 patients, 23 patients were treated with “U”-shaped tension screw, 10 patients were treated with hollow screw and 8 patients were treated with cortical bone screw. The evaluation index was tibiotalar angle. The general data, preoperative, postoperative and final follow-up imaging data were recorded, and the deformity correction rate and complications were compared. Results: all the patients were performed with postoperative follow-up visit for at least 12 months (31 months on average). In the “U”-shaped tension screw group, the preoperative tibiotalar angle was (74.8±4.8°), the tibiotalar angle was (85.8±4.5°) when the internal fixation was removed; in the hollow screw group, the average preoperative tibiotalar angle was (72.2±6.1°), the average tibiotalar angle was (88.4±5.1°) when the internal fixation was removed; in the cortical bone screw group, the average preoperative tibiotalar angle was (75.1±4.2°), the average tibiotalar angle was (88.4±5.1°) when the internal fixation was removed. The correction effect of the “U”-shaped tension screw group was better than that of the other two groups, but the difference was not significant (the correction rate of the “U”-shaped tension screw group was 0.71°/month, with that of in the hollow screw group and cortical bone screw group being 0.64°/month and 0.61°/month respectively, P＞0.05). One case of internal fixation complication was reported in the hollow screw group; two cases of missing correction effect were reported, one in cortical bone screw group and one in hollow screw group; and two cases showing symptom of wound pain were reported in the “U”-shaped screw group. Conclusion: Ankle valgus is a common postoperative complication of congenital tibial pseudarthrosis. Temporary hemiepiphyseal is an effective treatment for postoperative ankle valgus deformity of congenital pseudarthrosis of the tibia in children. Through comparison, the "U"-shaped tension screw provides relatively better orthopedic results and has a lower rate of internal fixation complications.

Utilization of S1 Foraminal Hooks for Augmentation of S1 Screws in Adult Spinal Deformity Surgery: Comparative Study With Iliac Screws

Objective: To compare the outcomes of S1 foraminal hooks and iliac screws regarding fusion rate at the lumbosacral junction and protective effects on S1 screws.Methods: From January 2017 to December 2019, consecutive patients who underwent long fusions (uppermost instrumented vertebra at or above L1) to the sacrum for adult spinal deformity were enrolled. Patients were divided into S1 foraminal hook group and iliac screw group. Radiographic parameters and the incidence of pseudarthrosis and instrument failure at the lumbosacral junction were compared between the groups.Results: Twenty-nine patients (male:female = 1:28) with a mean age of 73.6 ± 6.8 years were evaluated. Sixteen patients (55.2%) had S1 foraminal hook fixation and 13 patients (44.8%) had iliac screw fixation. Lumbar lordosis, sacral slope, and sagittal vertical axis did not differ between the groups preoperatively and postoperatively. The rate of L5/S1 pseudarthrosis was significantly higher in S1 foraminal hook group (5 of 16, 31.3%), compared to iliac screw group (0 of 13, 0%; p = 0.048). Instrument failure at the lumbosacral junction trended toward a higher rate in S1 foraminal hook group (6 of 16, 37.5%) than in iliac screw group (1 of 13, 7.7%), without statistical significance (p = 0.09). Proximal junctional kyphosis/failure occurred less often in S1 foraminal hook group (2 of 16, 12.5%) than in iliac screw group (3 of 13, 30.8%) without statistical significance (p = 0.36).Conclusion: Treatment with S1 foraminal hooks achieved equivalent satisfactory sagittal correction with proportioned alignment compared to that with iliac screws. However, S1 foraminal hooks did not provide enough structural support to the lumbosacral junction in long fusions to the sacrum.

Fixation stability and implant-associated complications in periacetabular osteotomy: a comparison of screw and K-wire fixation

Aims The aim of this study was to compare the fixation stability and complications in patients undergoing periacetabular osteotomy (PAO) with either K-wire or screw fixation. Patients and methods We performed a retrospective study to analyze a consecutive series of patients who underwent PAO with either screw or K-wire fixation. Patients who were treated for acetabular retroversion or had previous surgery on the ipsilateral hip joint were excluded. 172 patients (191 hips: 99 K-wire/92 screw fixation) were included. The mean age at the time of PAO was 29.3 years (16–48) in the K-wire group and 27.3 (15–45) in the screw group and 83.9% were female. Clinical parameters including duration of surgery, minor complications (soft tissue irritation and implant migration) and major complications (implant failure and non-union) were evaluated. Radiological parameters including LCE, TA and FHEI were measured preoperatively, postoperatively and at 3-months follow-up. Results Duration of surgery was significantly reduced in the K-wire group with 88.2 min (53–202) compared to the screw group with 119.7 min (50–261) (p < 0.001). Soft tissue irritation occurred significantly more often in the K-wire group (72/99) than in the screw group (36/92) (p < 0.001). No group showed significantly more implant migration than the other. No major complications were observed in either group. Postoperative LCE, TA and FHEI were improved significantly in both groups for all parameters (p = < 0.0001). There was no significant difference for initial or final correction for the respective parameters between the two groups. Furthermore, no significant difference in loss of correction was observed between the two groups for the respective parameters. Conclusion K-wire fixation is a viable and safe option for fragment fixation in PAO with similar stability and complication rates as screw fixation. An advantage of the method is the significantly reduced operative time. A disadvantage is the significantly higher rate of implant-associated soft tissue irritation, necessitating implant removal. Level of evidence III, retrospective trial.

Intramedullary Nailing Combined With Adjunct Plate or Blocking Screw for Proximal Tibial Fractures

Objective: To compare the traditional approach of intramedullary nail with an extra plate versus the nail combined with blocking screws for proximal tibia fractures without the knee involved. Methods: From January 2013 to January 2017, a total of 36 patients who suffered from proximal tibial fractures unaffecting the knee were enrolled into this prospective study, and divided into two groups by random number table method. Of them, 19 patients received an interlocking intramedullary nail combined with an extra plate for internal fixation of the fractures (the plate group), while the remaining 17 patients had fractures fixed with the nail combined with blocking screws (the screw group). The perioperative, follow-up and radiographic data were compared between the two groups. Results: All the 36 patients underwent operation smoothly without iatrogenic neurovascular injuries. The plate group proved superior the screw group regarding to operation time and intraoperative X-ray exposure (P＜0.05) , nevertheless the former was inferior to the latter in implant cost and hospital stay (P＜0.05) . The follow-up period lasted for 12～24 months with a mean of (15.62±4.71) months. There were no statistically significant differences in the time to return ambulation and the time to full weight-bearing activity between the two groups (P＞0.05) . At the latest follow up, no statistically significant differences were found between the two groups regarding knee range of motion and Johner-Wruhs grades for clinical consequences (P＞0.05) . In terms of anterior knee pain, the difference between the two groups was not statistically significant (P＞0.05) . In respect of radiographic assessment, the plate group had significantly less residual malalignment than the screw group, including anteroposterior and lateral displacements, as well as angulations in coronal and sagittal planes (P＜0.05) . To the latest follow up, all patients in both group got bony healing of the fractures without a statistical difference in fracture healing time between them (P＞0.05) , and no loosening or breaking of the implants were showed on images in anyone of them. Conclusion: Both the nail plus plate and nail plus blocking screw do achieve satisfactory clinical outcomes for proximal tibial fractures unaffecting the knee. By comparison, the nail combined with plate facilitates to regain and maintain better alignment of the leg regardless of higher implant cost.

Biomechanical Study of Cortical Bone Trajectory Screws in Intervertebral Fixation of Lumbar Tuberculosis

BackgroundWe aimed to explore the biomechanical stability and advantages of cortical bone trajectory (CBT) screws in the treatment of lumbar spine tuberculosis and provide biomechanical basis for the choice of clinical fixation methods. Methods16 pig spine specimens (T12-L5) were selected to simulate the lumbar spine(L2-L3) tuberculosis bone destruction model in vitro. The 16 specimens were randomly divided into 4 groups, and short segments (pedicle screws of the diseased vertebrae) were assigned respectively. Fixation (group A), short-segment fixation (group B), fixation with pedicle screw (group C), fixation with CBT screw (group D), 4 specimens in each group , Each specimen in each group was subjected to biomechanical testing in the state of complete specimen (state 1) and L2-3 spinal tuberculosis model bone graft fusion and internal fixation (state 2). Load each specimen on the spine 3D exercise machine, respectively apply moments of 2N·m, 2.5N·m, 1N·m, 3N·m, meanwhile record the movement of the specimens in the four directions of flexion，extension，lateral bending and torsion ROM, compare Simultaneously analyze each group of ROM. ResultsThe ROMs of flexion, extension, lateral bending, and torsion in group A in state 1 and state 3 modes were （8.47±1.76）°、 （7.01±1.10）°、 （5.03±0.92）°、 （4.48±0.41）°and （4.78±0.07）°、 （2.91±0.16）°、 （2.66±0.09）°、 （2.23±0.05）°; the ROMs of flexion, extension, lateral bending and torsion in group B in state 1 and state 3 modes were （7.32±0.75）°、 （5.35±0.69）°、 （3.44±0.51）°、 （3.36±1.02）°and（3.51±0.29）°、 （1.74±0.04）°、 （1.53±0.31）°、 （1.23±0.08）°; The ROMs of flexion, extension, lateral bending, and torsion in group C in state 1 and state 3 modes were （10.01±0.39）°、 （9.05±0.25）°、 （7.42±1.06）°、 （6.92±1.15）°and （7.21±0.17）°、 （5.07±0.02）°、 （5.12±0.74）°、 （4.58±0.01）°; The ROMs of flexion, extension, lateral bending, and torsion in group D in state 1 and state 3 modes were （9.20±1.37）°、 （7.38±0.88）°、 （6.89±1.22）°、 （6.00±0.52）°and （6.06±0.16）°、 （3.99±0.02）°、 （3.85±0.08）°、 （3.47±0.10）°. The ROM value of each fixed mode group under the state of bone graft fusion and internal fixation was lower than that of the intact state, and the difference was statistically significant (P<0.05)，The t values are 4.531, 5.346, 6.008, 4.149; 9.481, 16.181, 11.814, 4.769; 4.349, 8.002, 4.473, 4.800; 5.041, 4.146, 12.232, 10.58. ConclusionCBT screw disease intervertebral fixation can not only provide sufficient mechanical stability, but also provide stronger stability when using the same fixed segment, and The fixed segments are minimized.

CT-scan based anatomical study as a guidance for infra-acetabular screw placement

Background The infra-acetabular corridor is quite narrow, which makes a challenge for the orthopedists to insert the screw. This study aimed to explore the relationship between the infra-acetabular corridor diameter (IACD) and the minimum thickness of medial acetabular wall (MTMAW), and to clarify the way of screw placement. Methods The Computed tomography (CT) data of 100 normal adult pelvises (50 males and 50 females respectively) were collected and pelvis three-dimensional (3D) reconstruction was performed by using Mimics software and the 3D model was imported into Geomagic Studio software. The perspective of acetabulum was carried out orienting from iliopubic eminence to ischial tuberosity and the IACD was measured by placing virtual screws which was vertical to the corridor transverse section of “teardrop”. The relationship between IACD and MTMAW was analyzed. When IACD was ≥5 mm, 3.5 mm all-in screws were placed. When IACD was < 5 mm, 3.5 mm in-out-in screws were placed. Results The IACD of males and females were (6.15 ± 1.24) mm and (5.42 ± 1.01) mm and the MTMAW in males and females were (4.40 ± 1.23) mm and (3.60 ± 0.81) mm respectively. The IACD and MTMAW in males were significantly wider than those of females (P < 0.05), and IACD was positively correlated with MTMAW (r = 0.859), the regression equation was IACD = 2.111 + 0.917 MTMAW. In the all-in screw group, 38 cases (76%) were males and 33 cases (66%) were females respectively. The entry point was located at posteromedial of the apex of iliopubic eminence, and the posterior distance and medial distance were (8.03 ± 2.01) mm and (8.49 ± 2.68) mm respectively in males. As for females, those were (8.68 ± 2.35) mm and (8.87 ± 2.79) mm respectively. In the in-out-in screw group, 12 cases (24%) were males and 17 cases (34%) were females, respectively. The posterior distance and medial distance between the entry point and the apex of iliopubic eminence were (10.49 ± 2.58) mm and (6.17 ± 1.84) mm respectively in males. As for females, those were (10.10 ± 2.63) mm and (6.63 ± 1.49) mm respectively. The angle between the infra-acetabular screw and the sagittal plane was medial inclination (0.42 ± 6.49) °in males, lateral inclination (8.09 ± 6.33) °in females, and the angle between the infra-acetabular screw and the coronal plane was posterior inclination (54.06 ± 7.37) °. Conclusions The placement mode of the infra-acetabular screw (IAS) can be determined preoperatively by measuring the MTMAW in the CT axial layers. Compared with all-in screw, the in-out-in screw entry point was around 2 mm outwards and backwards, and closer to true pelvic rim.