Percutaneous Fixation with Internal Cemented Screws for Iliac Lytic Bone Metastases: Assessment of Pain and Quality of Life on Long Term Follow-up

PURPOSE

To assess effectiveness on pain, quality of life and late adverse events of percutaneous fixation with internal cemented screw (FICS) among patients with iliac lytic bone metastases with or without pathological fractures.

MATERIALS AND METHODS

This retrospective exploratory study analyzed FICS procedures on iliac osteolytic bone lesions with and without pathological fracture performed from July 2019 to January 2022 in one tertiary level university hospital. The procedure were performed under general anesthesia, and were CT and fluoroscopically guided. Numerical Pain Rate Score (NPRS), mean EuroQol visual analogue scale (EQ VAS), morphine consumption, walking ability, walking perimeter and presence of walking aids and the appearance of complications were evaluated.

RESULTS

Nineteen procedures among 18 patients were carried out with a mean follow up time of 243.3 ± 243.2 days. The mean of the maximum NPRS decreased from 8.4 ± 1.3 to 2.2 ± 3.1 at 1 month (p < 0.01) and remained between 1.3 and 4.1 during a follow-up consultation period of 3-24 months. The mean EQ VAS rose from 42.0 ± 12.5 to 57.3 ± 13.9 at 1 month (p < 0.01) follow-up and remained between 55.8 and 62.5 thereafter. No patient scores returned to pre-procedure levels during follow-up. Mean morphine use decreased from 111.1 ± 118.1 to 57.8 ± 70.3 mg/d at 1 month (p > 0.05) follow-up. No late adverse events were reported.

CONCLUSION

Percutaneous FICS is a safe procedure with fast and long-standing effect on pain, mobility and quality of life. It can be used as a complement to the known analgesic therapeutic arsenal for bone metastases.

Feasibility of a novel augmented reality overlay for cervical screw placement in phantom spine models

Study Design

Feasibility study.

Purpose

A phantom model was used to evaluate the accuracy of a novel augmented reality (AR) system for cervical screw placement.

Overview of Literature

The use of navigation systems is becoming increasingly common in spine procedures. However, numerous factors limit the feasibility of regular and widespread use of navigation tools during spine surgery. AR is a new technology that has already demonstrated utility as a navigation tool during spine surgery. However, advancements in AR technology are needed to increase its adoption by the medical community.

Methods

AR technology that uses a fiducial-less registration system was tested in a preclinical cervical spine phantom model study for accuracy during spinal screw placement. A three-dimensional reconstruction of the spine along with trajectory lines was superimposed onto the phantom model using an AR headset. Participants used the AR system to guide screw placement, and post-instrumentation scans were compared for accuracy assessment.

Results

Twelve cervical screws were placed under AR guidance. All screws were placed in an acceptable anatomic position. The average distance error for the insertion point was 2.73±0.55 mm, whereas that for the endpoint was 2.71±0.69 mm. The average trajectory angle error for all insertions was 2.69°±0.59°.

Conclusions

This feasibility study describes a novel registration approach that superimposes spinal anatomy and trajectories onto the surgeon's real-world view of the spine. These results demonstrate reasonable accuracy in the preclinical model. The results of this study demonstrate that this technology can assist with accurate screw placement. Further investigation using cadaveric and clinical models is warranted.

Clinical Analysis of Microwave Ablation Combined with Decompression and Pedicle Screw Fixation in the Treatment of Spinal Metastases

OBJECTIVES

There is still controversy over the choice of treatment for end-stage spinal metastases. With the continuous development of microwave technology in spinal tumors, related studies have reported that microwave combined with techniques such as pedicle screw fixation and percutaneous vertebroplasty can achieve the purpose of tumor ablation, relieving spinal cord compression, enhancing spinal stability, effectively relieving pain, and reducing recurrence rates. This study aimed to analyze the effectiveness of microwave ablation combined with decompression and pedicle screw fixation in the palliative management of spinal metastases with pathological fractures.

METHODS

This retrospective study enrolled 82 patients with spinal metastases and pathological fractures treated between January 2016 and July 2020, with 44 patients undergoing pedicle screw fixation along with laminectomy (fixation group) and the remaining 38 receiving microwave ablation in addition to the treatment provided to group fixation (MWA group). Before surgery, all patients underwent pain assessment using the visual analogue scale (VAS) and evaluation of spinal cord injury using the Frankel classification. After surgery, the patients' prognoses were assessed using the Tomita score, modified Tokuhashi score system, and progression-free survival. Additionally, we compared operative time and blood loss between the two groups. Survival analysis utilized the Kaplan-Meier method with a log-rank test for group comparisons. Paired t-tests and the Mann-Whitney U test were applied to metric and non-normally distributed data, respectively. Neurological function improvement across groups was evaluated using the χ2 test.

RESULTS

All patients were followed up for a median duration of 18 and 20 months in the fixation and MWA groups, respectively, with follow-up periods ranging from 6 to 36 months. Statistically significant reductions in postoperative VAS scores were observed in all patients compared with their preoperative scores. The MWA group exhibited reduced blood loss (t = 2.74, p = 0.01), lower VAS scores at the 1- and 3-month follow-ups (t = 2.34, P = 0.02; t = 2.83, p = 0.006), and longer progression-free survival than the fixation group (p = 0.03). Although the operation times in the MWA group were longer than those in the fixation group, this difference was not statistically significant (t = 6.06, p = 0.12). No statistically significant differences were found regarding improvements in spinal cord function between the two groups (p = 0.77).

CONCLUSION

Compared with decompression and pedicle screw fixation for treating spinal metastases with pathological fractures, microwave ablation combined with decompression and pedicle screw fixation showed better outcomes in terms of pain control, longer progression-free survival, and lower blood loss without increasing operative time, which has favorable implications for clinical practice.

Operative outcomes and fracture patterns in dysmorphic sacrums

INTRODUCTION

Sacral dysmorphism has been previously reported to occur in 30 % to 40 % of adult patients. It has been described by 6 widely accepted parameters on outlet x-ray views of the pelvis: steep alar slope, retained S1-S2 disk, presence of mamillary bodies, sacralized L5, tongue in groove SI joint, and non-round neural foramina. Studies have focused on the importance of identifying dysmorphism for safe treatment of fractures in pelvises with dysmorphic upper sacral segments. Less is known regarding whether dysmorphism may be protective against trauma. To our knowledge no studies have focused on how dysmorphic sacrums fracture compared to non-dysmorphic (ND) sacrums, and whether operative rates are different.

AIMS

To assess the rate of operative fixation of sacral fractures between pelvises with dysmorphic and ND sacrums, as well as whether a difference exists in fracture morphology between groups.

DESIGN/METHODS

This is a retrospective cohort study out of a single level 1 trauma center. Study participants consisted of those sustaining a pelvic ring injury who were 18 years or older in which orthopaedics was consulted, had CT imaging available, and did not have isolated acetabulum fractures. 355 subjects were included of 671 reviewed pelvic ring injuries. Sacrums were deemed dysmorphic if they met at least one of the six dysmorphic features, and it was determined whether they underwent operative intervention. Fracture classifications and patterning were identified on CT imaging. P values were set <0.05.

RESULTS

We found that 44 % of inclusions had a dysmorphic sacrum with the most common feature to be a steep alar slope (68 %). 17.17 % of subjects with a ND sacrum underwent treatment versus 16.56 % for dysmorphic sacrums. No statistical difference regarding operative fixation rates was uncovered (p = .879). However, we found a difference in fracture patterns regarding ipsilateral posterior SI joint widening (p = 0.020).

CONCLUSION

Our study suggests that sacral dysmorphism is not protective against operative fixation based on no difference in operative rates between groups. However, our data supports that pelvises with dysmorphic sacrums may fracture differently based on the difference observed regarding other pelvic ring injuries.

Computed Tomography-Based Morphometric Analysis of Lower Cervical Anterior Transpedicular Screw Fixation and Related Factors in the Chinese Population

BACKGROUND

Anterior transpedicular screw (ATPS) internal fixation of the lower cervical spine is an alternative for patients who cannot tolerate combined anterior and posterior surgery. The cervical vertebral anatomy varies with many factors, including age, gender, height, weight, and race.

METHODS

Three-dimensional (3D) CT reconstructions were performed on 122 patients. We selected the best level and measured the relevant parameters on both sides of the cervical vertebrae.

RESULTS

We identified the entry point and orientation parameters of ATPS fixation for the C3-C7 vertebrae, and analyzed cervical pedicle parameters. Outer pedicle width (OPW), outer pedicle height (OPH), and pedicle axis length (PAL) were not correlated with body weight and age, but were positively correlated with body height (P < 0.05). After multiple linear regression analysis to exclude the effects of body height, no significant differences in OPW, OPH, and PAL were found between male and female subjects at most cervical levels. Pedicle cortical thickness was negatively correlated with age (P < 0.05). The percentage of pedicles with OPW <4.5 mm was: C3, 38.10%; C4, 34.92%; C5, 12.70%; C6, 9.52%; and C7, 0%. The percentage of pedicles with OPWs ≤4.5 mm, ≤4.0 mm, and ≤3.5 mm was higher among subjects with body height <160 cm.

CONCLUSIONS

This study presents the internal anatomy of the cervical spine and provides accurate preoperative evaluation data for ATPS fixation. OPW, OPH, and PAL are positively correlated with body height, while pedicle cortical thickness is negatively correlated with age.

Syndesmotic injury with ankle fracture: A systematic review of screw vs dynamic fixation

Cortical screw fixation across the tibiofibular joint is the mainstay of treatment for syndesmotic injury. Dynamic fixation devices have been developed offering similar advantages to screw fixation in terms of reduction and stability of the syndesmosis. Dynamic fixation may also facilitate a more physiological movement between the tibiofibular joint and thus incur less morbidity. Patient's rehabilitation potential is enhanced and reduces the need for hardware removal. Our systematic review aims to analyse the relevant current literature and compare screw fixation to dynamic fixation in the treatment of syndesmotic injury associated with acute ankle fractures. A literature search was performed on Pubmed and Ovid Medline to find scientific papers relating to syndesmotic fixation in acute ankle fractures. Papers were screened and included dependent on predetermined criteria. Risk of bias was assessed after screening full papers by two independent reviewers. Tables and analysis were made using Microsoft excel. A total of 8 papers with 673 patients were included. We found no functional difference between screw fixation or dynamic fixation groups at final follow-up. Three papers showed statistically significant lower rates of reoperation in the dynamic fixation group. Dynamic fixation may offer lower post operative complications and reoperation rates. Therefore, dynamic fixation may be a beneficial alternative treatment compared to traditionally used syndesmotic screws.

Rigid fixation of pelvic tracker essential for accurate cup placement in CT-based navigation total hip arthroplasty

Research is lacking on the effect of intraoperative pelvic tracker displacement relative to the pelvis on cup orientation accuracy in computed tomography (CT)-based navigation (CTN) or multivariable analysis to detect factors associated with CTN accuracy. Here, we asked: (1) how pelvic tracker displacement influences the CTN accuracy of cup orientation in total hip arthroplasty (THA)? and (2) what factors are associated with CTN accuracy on multivariable analysis? Regarding cup orientation in 446 THA procedures using CTN, we evaluated clinical error defined as the difference between postoperative measurement and preoperative planning and measurement error defined as the difference between postoperative and intraoperative measurements. Multivariable regression analyses detected the associated factors. Subjects with an intraoperative tracker displacement of < 2 mm were classified in the verified group. Mean absolute clinical and measurement errors were < 1.5° in the verified group, whereas the measurement error of 2.6° for cup inclination and 1.3° for anteversion was larger in the non-verified versus verified group. Tracker displacement and screw fixation were associated with larger clinical errors, while tracker displacement and surgeon inexperience were associated with larger measurement errors. Clinical and measurement accuracies were high for CTN cup placement with rigid pelvic tracker fixation.

Compressive buttress compared with off-axial screw fixation for vertical femoral neck fractures in young adults: a prospective, randomized controlled trial

BACKGROUND

To compare the clinical outcomes of compressive buttress screw (CBS) fixation, a novel screw fixation strategy, to off-axial screw fixation (off-axial partial threaded cannulated screw, OPTCS) for vertical femoral neck fractures (FNFs) in young adults.

METHODS

A total of 146 adults younger than 55 years old with high-energy Pauwels type III FNFs were randomized to receive CBS fixation or OPTCS fixation. Primary outcomes were complication rates, including fixation failure, fracture nonunion, and avascular necrosis of the femoral head (ANFH) at 24 months after treatment. Fixation loosening, femoral neck shortening and varus collapse, patient function and quality of life using the Harris hip score (HHS), and EuroQol-5 dimensional-5 levels (EQ-5D-5L) questionnaire (including EQ-5D-5L and EQ-VAS) were assessed as secondary outcomes at 24 months.

RESULTS

CBS and OPTCS fixation groups were similar with regard to demographics at baseline. At 24 months, patients in the CBS fixation cohort had a significantly lower rate of fixation failure (10.5% vs. 25.0%, p = 0.041) and fracture nonunion (1.8% vs. 18.3%, p = 0.003) compared with patients who received OPTCS fixation. There was no difference in rate of ANFH (7.0% vs. 11.7%, p = 0.389) between groups. Additionally, patients managed with CBS fixation showed significantly less fixation loosening (19.3% vs. 58.3%, p < 0.001), less severe femoral neck shortening and varus collapse (10.5% vs. 25.0%, p = 0.007), higher HHS (93 vs. 83, p = 0.001) and more excellent grade (68.4% vs. 36.7%, p = 0.008), higher EQ-5D-5L (0.814 vs, 0.581, p < 0.001) and EQ-VAS (85 vs. 80, p = 0.002).

CONCLUSION

CBS screw fixation confers significantly lower complication rate in addition to higher functional and quality of life outcomes for young adults with high-energy FNF compared with OPTCS fixation.

TRIAL REGISTRATION

This prospective, randomized controlled trial was approved by the institutional review board of our center, Ethics Committee of Shanghai sixth people's Hospital, and registered at www.chictr.org.cn (Approval Number: ChiCTR1900026283; Registered 29 September 2019-Retrospectively registered, https://www.chictr.org.cn/showproj.html?proj=43164 ).

Finite element analyses of three minimally invasive fixation techniques for treating Sanders type II intra-articular calcaneal fractures

BACKGROUND AND OBJECTIVE

Calcaneal Sanders type II or III fractures are highly disabling with significant burden. Surgical treatment modalities include open reduction and internal fixation (ORIF) techniques and a variety of minimally invasive surgical (MIS) approaches. ORIF techniques are associated with complications and traditional MIS techniques need extensive intraoperative fluoroscopic procedures. The present study aims to investigate the effects of three different minimally invasive internal fixation (MIIF) techniques used to treat Sanders type II intra-articular calcaneal fractures using finite element analyses.

METHODS

A 64-row spiral computed tomography scan was used to observe the calcaneus of a healthy adult. The scanning data were imported into Mimics in a DICOM format. Using a new model of a Sanders type II-B intra-articular calcaneal fracture, three minimally invasive techniques were simulated. Technique A involved fixation using an isolated minimally invasive locking plate; Technique B used a minimally invasive locking plate with one medial support screw; and Technique C simulated a screw fixation technique using four 4.0-mm screws. After simulating a 640-N load on the subtalar facet, the maximum displacement and von Mises stress of fragments and implants were recorded to evaluate the biomechanical stability of different fixation techniques using finite element analyses.

RESULTS

After stress loading, the maximum displacements of the fragments and implants were located at the sustentaculum tali and the tip of sustentaculum tali screw, respectively, in the three techniques; however, among the three techniques, Technique B had better results for displacement of both. The maximum von Mises stress on the fragments was < 56 Mpa, and stress on the implants using the three techniques was less than the yield strength, with Technique C having the least stress.

CONCLUSION

All three techniques were successful in providing a stable fixation for Sanders type II intra-articular calcaneal fractures, while the minimally invasive calcaneal locking plate with medial support screw fixation approach exhibited greater stability, leading to improved enhancement for the facet fragment; however, screw fixation dispersed the stress more effectively than the other two techniques.

Standard views do not suffice in assessing distal scaphoid articular cannulated screw penetration

BACKGROUND

Articular screw penetration is one of the most common hardware-related problems after scaphoid fracture fixation, occurring in up to two-thirds of patients, in particular into the scaphotrapezotrapezoidal (STT) joint. The aim of this study was to investigate whether this clinically important issue could be detected using standard anteroposterior (AP) and lateral, as well as additional nonstandard fluoroscopic views using direct open visualization with magnifying loupes as reference standard.

MATERIALS AND METHODS

Ten fresh cadaver wrists were used for this imaging study. A 2.2 mm cannulated compression screws with a length of 24 mm was placed in the scaphoid and incrementally left to protrude at the STT joint up to 2 mm. Eight fluoroscopic views of the wrist were then obtained by rotating the forearm using goniometric measurements, keeping the image beam parallel to the floor: (1) anteroposterior with the wrist in neutral rotation, (2) anteroposterior with the wrist in ulnar deviation, (3) supinated oblique 60° from neutral (60° supinated oblique), (4) supinated oblique 45° from neutral (45° supinated oblique), (5) a true lateral, (6) a true lateral with the wrist in radial deviation, (7) pronated oblique 45° from neutral (45° pronated oblique), and (8) a pronated oblique 60° from neutral (60° pronated oblique).

RESULTS

Standard anteroposterior and lateral fluoroscopy views (radiographically calibrated) of a percutaneous cannulated screw fixation of a scaphoid fracture were insufficient to detect distal articular penetration, missing half the amount of screw penetrations in the current study. The 45° pronated oblique view was found as the most sensitive in detecting STT penetration (p < 0.0001).

CONCLUSIONS

Standard anteroposterior and lateral fluoroscopy views of a percutaneous cannulated screw fixation of a scaphoid waist fracture are insufficient to detect STT screw penetration. According to the current study, standard views would have missed half the amount of screw penetrations, which seems to reflect the high incidence of this problem in current practice. The most sensitive view was the 45° pronated oblique view, which detected STT screw penetration in all cases. Level of Evidence Not applicable.

Tunnel widening after ACL reconstruction with different fixation techniques: aperture fixation with biodegradable interference screws versus all-inside technique with suspensory cortical buttons. 5-year data from a prospective randomized trial

BACKGROUND

The aim of the present study was to examine tunnel widening and clinical outcomes after anterior cruciate ligament reconstruction (ACLR) using two different fixation methods: aperture fixation with biodegradable interference screws versus all-inside ACLR with suspensory cortical buttons.

METHODS

Tunnel widening was assessed using volumetric and diameter measurements on magnetic resonance imaging (MRI) scans directly after surgery, as well as 6 months and 2 and 5 years postoperatively. Clinical outcomes were assessed after 5 years with instrumented tibial anteroposterior translation measurement (KT-1000), single-leg hop testing, and the IKDC, Lysholm, and Tegner activity scores.

RESULTS

At the final follow-up, the study population consisted of 21 patients, 12 of whom underwent screw fixation and 9 of whom had button fixation. 3 patients with all-inside ACLR had sustained early repeat ruptures within 6 months after surgery and had to be excluded from the further analysis. With screw fixation, the tibial tunnel volume changed significantly more over time compared to all-inside button fixation, with a larger initial increase at 6 months (from postoperative 2.9 ± 0.2 to 3.3 ± 0.2 cm3 at 6 months versus 1.7 ± 0.1 to 1.9 ± 0.2 cm3) and a greater final decrease over 2-5 years postoperatively (from 3.1 ± 0.2 to 1.9 ± 0.2 cm3 versus 1.8 ± 0.2 ± 0.1 to 1.3 ± 0.1 cm3) (P < 0.001). The femoral tunnel volume remained comparable between the two groups throughout the follow-up period, with an initial 1.6 ± 0.1 cm3 in both groups and 1.2 ± 0.1 vs. 1.3 ± 0.1 after 5 years in the screw and button groups, respectively (P ≥ 0.314). The maximum tibial and femoral tunnel diameters were significantly larger with screw fixation at all four time points. Tibial diameters measured 11.1 ± 0.2, 12.3 ± 0.3, 12.3 ± 0.4, and 11.2 ± 0.4 mm in the screw group versus 8.1 ± 0.3, 8.9 ± 0.3, 9.1 ± 0.4 and 8.2 ± 0.5 mm in the button group (P < 0.001). Femoral diameters measured 8.6 ± 0.2, 10.5 ± 0.4, 10.2 ± 0.3, and 8.9 ± 0.3 versus 7.3 ± 0.3, 8.4 ± 0.4, 8.4 ± 0.3, 7.5 ± 0.3, respectively (P ≤ 0.007). Four patients (33%) in the screw group exceeded a diameter of 12 mm on the tibial side after 5 years versus none in the button group (not significant, P = 0.104). Tibial anteroposterior translation measurement with KT-1000 after 5 years was 2.3 ± 2.4 mm in the screw group versus 3.2 ± 3.5 mm in the button group (not significant, P = 0.602). There were no significant differences between the groups in any of the other clinical outcomes.

CONCLUSION

Tibial tunnels in ACLR with screw fixation were associated with a larger increase in tunnel volume within the first 2 years and a greater decrease up to 5 years after surgery, while femoral tunnel volumes did not differ significantly. On the tibial side, the need for staged revision ACLR may be greater after biodegradable interference screw fixation if repeat ruptures occur, especially within the first 2 years after primary ACLR. Concerns may remain regarding a higher graft failure rate with all-inside ACLR.

LEVEL OF EVIDENCE

II.

RCT CONSORT

NCT01755819.

Three-dimensional printed cast assisted screw fixation of calcaneal fractures: a prospective study

BACKGROUND

Treatment of displaced intra-articular calcaneal fractures (DIACFs) with percutaneous screw fixation remains defective in some aspects. A novel three-dimensional (3D) printed cast was devised to assist screw placement. This study assessed the radiological and functional outcomes of 3D-printed cast assisted screw fixation for patients with DIACFs.

METHODS

Patients with unilateral Sanders type II or III DIACFs admitted to a single-centre hospital underwent either 3D-printed cast assisted screw fixation (3D group) or minimally invasive plate fixation (control group) from September 2020 to November 2022. All patients were assessed at one, two, three, and six months of follow-up. Comparison between groups was conducted in operative duration, fluoroscopic times, radiographic measurements of the calcaneus, and the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score.

RESULTS

A total of 32 patients were enrolled (19 in the 3D group versus 13 in the control group). Significant differences were detected between the 3D group and control group in operative duration (53.63±8.95 min, 95.08±8.31 min, P <0.001), fluoroscopic times (7.37±1.21, 16.85±1.57, P <0.001). At a follow-up of six months, the 3D group showed better restoration than the control group in calcaneal width, height, Bohler angle, and AOFAS Ankle-Hindfoot scores (all P <0.001). No significant differences were shown in calcaneal length and Gissane angle (P >0.05). No wound-related complications occurred in either group.

CONCLUSION

The 3D-printed cast assisted screw fixation has shown superiority over minimally invasive plate fixation in the operative duration, fluoroscopic exposure, morphological restoration of the calcaneus, and functional outcomes in the treatment of DIACFs.

A Clinical Comparative Study on Percutaneous and Open Approaches for Screw Internal Fixation in Treating Thoracolumbar Fractures

OBJECTIVE

Conventional open internal fixation surgery for thoracolumbar fractures has many complications and long recovery time. There are few clinical studies on the minimally invasive percutaneous injured vertebrae screw internal fixation. The purpose of this paper is to evaluate the application value of minimally invasive percutaneous injured vertebrae screw internal fixation in the treatment of thoracolumbar fractures (TF).

METHODS

A total of 98 patients with TF admitted to our hospital from January 2019 to December 2021 were retrospectively enrolled. According to the surgical method, the patients were divided into the study group (n = 49, treated with minimally invasive percutaneous injured vertebrae screw internal fixation) and the control group (n = 49, treated with traditional open internal fixation surgery). The two groups were compared in the perioperative period, the degree of pain at different periods, the percentage of the height of the anterior edge of the injured vertebra, the Cobb angle of the injured vertebra body and the wedge angle of the injured vertebra body at the first week and the last follow-up, and the postoperative complications and the occurrence of the cone shell after the operation were recorded. Then, statistical analysis such as Student's t test or Chi-Square test was performed.

RESULTS

The operation time (p = 0.002), intraoperative blood loss (p < 0.001), postoperative drainage volume (p = 0.011), and length of hospital stay (p = 0.003) in the study group were significantly lower than that in the control group. The VAS in the study group (3.38 ± 1.02) was significantly lower than that in the control group (4.56 ± 1.04) on the 7th day after the operation, with a significant difference (p < 0.001). The correction values of the percentage of leading edge height (LEH), Cobb angle, wedge angle in the study group were significantly lower than that in the control group at 1 week after surgery (all ps < 0.001). The incidence of postoperative complications in the study group (one case, 2.04%) was significantly lower than that in the control group (seven cases, 14.29%) (p = 0.031). At 1 month, 6 months, 10 months, and the last follow-up, the incidence of "empty shell" on CT scan in the study group were lower than that in the control group with a significant difference (all ps < 0.05).

CONCLUSION

Applying minimally invasive percutaneous injured vertebrae screw internal fixation is more beneficial to shorten the operation time and hospital stay, with fewer postoperative complications.

Optimal additional support screw position for prevention of hinge fracture in biplanar closed wedge distal femoral osteotomy

Background

The purpose of this study was to examine the biomechanical significance of supplemental fixation using a positional screw in prevention of the hinge fracture in lateral closed-wedge distal femoral osteotomy (LCW-DFO) by means of a three-dimensional finite element analysis.

Methods

The three-dimensional numerical knee models with LCW-DFO were developed. To assess the mechanical efficacy of the positional screw and determine its optimal position and orientation, in total, 13 screwing methods were analyzed. In the first four methods, the screw was supported by the cortical bone only on the medial surface (mono-cortical). In the other 9 models, the screw was supported by both medial and lateral cortical bones (bi-cortical). Under 1000 N of vertical force and 5 Nm of rotational torques, the highest shear stress value around the medial hinge area was adopted as an analytical parameter.

Results

In mono-cortical methods, with the cancellous bone support, all methods were able to reduce the highest stress value compared to the value without the screw, while the efficacy was rather inferior when the screw was in horizontal direction. Without the cancellous bone support, however, all methods were not able to reduce the stress value. In bi-cortical methods, with the cancellous bone support, almost all screw augmentation methods were able to reduce the stress value. When screwing from the medial to the lateral, it only gets worse when going extremely posterior. Without the cancellous bone support, all methods were able to reduce the stress value.

Conclusion

The mechanical efficacy of the bi-cortical method was proven regardless of the quality of the local cancellous bone.

Tension band wiring versus screw fixation for the treatment of medial malleolar fractures: A systematic review and meta-analysis

INTRODUCTION

Tension band wiring (TBW) and screw fixation (SF) are common surgical treatments for medial malleolar fractures (MMFs); however, no systematic review has identified which fixation method is superior. This study aimed to determine the most optimal MMF fixation method by comparing the clinical and radiological outcomes of TBW and SF through a systematic review and meta-analysis of the literature.

HYPOTHESIS

We hypothesized that there may be differences in outcomes between TBW and SF for treating MMFs.

METHODS

MEDLINE, Embase, and the Cochrane Library were systematically searched for studies that compared TBW and SF for MMF treatment published through June 8, 2021. Fracture union, outcome scores, and postoperative complications were analyzed.

RESULTS

We included 10 studies with 512 MMF cases; 218 and 294 patients were treated with TBW and SF, respectively. Pooled analysis revealed no significant differences between them for all outcome variables, including the time to fracture union (mean difference=-0.59 weeks; 95% confidence interval [CI], -1.82 to 0.64; p=0.35; I2=70%), number of excellent or good outcomes based on the final Olerud and Molander Ankle score (odds ratio [OR], 1.46; 95% CI, 0.53-5.02; p=0.47; I2=0%), delayed union rate (OR, 0.94; 95% CI, 0.34-2.59; p=0.91; I2=17%), superficial infection rate (OR, 1.19; 95% CI, 0.33-4.26; p=0.79; I2=0%), and number of fixation failures (OR, 0.53; 95% CI, 0.16-1.74; p=0.29; I2=13%).

CONCLUSIONS

Both TBW and SF are excellent clinical and radiological methods for MMF fixation. However, an appropriate fixation method should be chosen according to the fracture type and size and bone quality considering the advantages and disadvantages of each method.

LEVEL OF EVIDENCE

III, meta-analysis.

K-wire versus screws in the fixation of lateral condyle fracture of humerus in pediatrics: a systematic review and meta-analysis

BACKGROUND

Lateral condyle fracture of the humerus is the second most common elbow fracture in children. Non-displaced lateral condyle fractures can often be managed with cast and conservative care, while reduction and fixation are often used to treat displaced lateral condyle fractures. Traditionally, K-wire fixation has been used for displaced lateral condyle fractures, but recently fixation using screws has been advocated in some studies. Therefore, we performed a meta-analysis to determine the difference in outcomes and complications between the two different fixation methods for the treatment of displaced lateral condyle fractures of the humerus in pediatric patients.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for this review. PubMed, Embase, and Cochrane Library were used for study selection. Studies comparing K-wires and screw fixation in displaced lateral condyle fractures in pediatric patients were included. Clinical outcomes using the Hardacre criteria, infection, limitation of range of motion of the elbow, lateral condyle overgrowth, delayed union, nonunion, and avascular necrosis were compared. Data were analyzed using the meta package in R version 4.2.2, and random-effects or fixed-effects models were used according to heterogeneity.

RESULTS

One randomized controlled study and three retrospective cohort studies were included, with a total of 240 patients (K-wire:118, screw:122). The clinical outcome using the Hardacre criteria was not different between the groups (P = 0.54), but the risk of infection (risk ratio [RR] = 5.52, 95% CI: 1.42-21.48, P = 0.01) and limitation of range of motion (RR = 3.75, 95% CI: 1.54-9.18, P < 0.01) were significantly higher in the K-wire fixation group than in screw fixation group.

CONCLUSIONS

The use of screws for fixation after reduction in the treatment of lateral condyle fracture of the humerus in children decreases the risk of superficial infection and elbow stiffness compared with the use of K-wire. Although removal of the implant under general anesthesia is necessary, screw fixation can be considered in displaced lateral condyle fractures of the humerus in children.

TRIAL REGISTRATION

PROSPERO (CRD42023415643).

Comparison of four different screw configurations for the fixation of Fulkerson osteotomy: a finite element analysis

BACKGROUND

Conventionally, two 4.5 mm cortical screws inserted toward the posterior tibial cortex are usually advocated for the fixation of Fulkerson osteotomy. This finite element analysis aimed to compare the biomechanical behavior of four different screw configurations to fix the Fulkerson osteotomy.

MATERIALS AND METHODS

Fulkerson osteotomy was modeled using computerized tomography (CT) data of a patient with patellofemoral instability and fixed with four different screw configurations using two 4.5 mm cortical screws in the axial plane. The configurations were as follows: (1) two screws perpendicular to the osteotomy plane, (2) two screws perpendicular to the posterior cortex of the tibia, (3) the upper screw perpendicular to the osteotomy plane, but the lower screw is perpendicular to the posterior cortex of the tibia, and (4) the reverse position of the screw configuration in the third scenario. Gap formation, sliding, displacement, frictional stress, and deformation of the components were calculated and reported.

RESULTS

The osteotomy fragment moved superiorly after loading the models with 1654 N patellar tendon traction force. Since the proximal cut is sloped (bevel-cut osteotomy), the osteotomy fragment slid and rested on the upper tibial surface. Afterward, the upper surface of the osteotomy fragment acted as a fulcrum, and the distal part of the fragment began to separate from the tibia while the screws resisted the displacement. The resultant total displacement was 0.319 mm, 0.307 mm, 0.333 mm, and 0.245 mm from the first scenario to the fourth scenario, respectively. The minimum displacement was detected in the fourth scenario (upper screw perpendicular to the osteotomy plane and lower screw perpendicular to the posterior tibial cortex). Maximum frictional stress and maximum pressure between components on both surfaces were highest in the first scenario (both screws perpendicular to the osteotomy plane).

CONCLUSIONS

A divergent screw configuration in which the upper screw is inserted perpendicular to the osteotomy plane and the lower screw is inserted perpendicular to the posterior tibial cortex might be a better option for the fixation of Fulkerson osteotomy. Level of evidence Level V, mechanism-based reasoning.

Simulated full weight bearing following posterior column acetabular fracture fixation: a biomechanical comparability study

PURPOSE

The incidence of acetabular fractures (AFs) is increasing in all industrial nations, with posterior column fractures (PCFs) accounting for 18.5-22% of these cases. Treating displaced AFs in elderly patients is a known challenge. The optimal surgical strategy implementing open reduction and internal fixation (ORIF), total hip arthroplasty (THA), or percutaneous screw fixation (SF), remains debated. Additionally, with either of these treatment methods, the post-surgical weight bearing protocols are also ambiguous. The aim of this biomechanical study was to evaluate construct stiffness and failure load following a PCF fixation with either standard plate osteosynthesis, SF, or using a screwable cup for THA under full weight bearing conditions.

METHODS

Twelve composite osteoporotic pelvises were used. A PCF according to the Letournel Classification was created in 24 hemi-pelvis constructs stratified into three groups (n = 8) as follows: (i) posterior column fracture with plate fixation (PCPF); (ii) posterior column fracture with SF (PCSF); (iii) posterior column fracture with screwable cup fixation (PCSC). All specimens were biomechanically tested under progressively increasing cyclic loading until failure, with monitoring of the interfragmentary movements via motion tracking.

RESULTS

Initial construct stiffness (N/mm) was 154.8 ± 68.3 for PCPF, 107.3 ± 41.0 for PCSF, and 133.3 ± 27.5 for PCSC, with no significant differences among the groups, p = 0.173. Cycles to failure and failure load were 7822 ± 2281 and 982.2 ± 428.1 N for PCPF, 3662 ± 1664 and 566.2 ± 366.4 N for PCSF, and 5989 ± 3440 and 798.9 ± 544.0 N for PCSC, being significantly higher for PCPF versus PCSF, p = 0.012.

CONCLUSION

Standard ORIF of PCF with either plate osteosynthesis or using a screwable cup for THA demonstrated encouraging results for application of a post-surgical treatment concept with a full weight bearing approach. Further biomechanical cadaveric studies with larger sample size should be initiated for a better understanding of AF treatment with full weight bearing and its potential as a concept for PCF fixation.

A network meta-analysis of the efficacy of arthrodesis with various fixation methods in the treatment of advanced ankle osteoarthritis

This study aimed to compare the efficacy of arthrodesis with various fixation methods in the treatment of advanced ankle osteoarthritis. Thirty-two patients with osteoarthritis of the ankle (mean age 59.91±6.16 years) took part in the study. The patients were divided into 2 groups - Ilizarov apparatus (21 patients) and screw fixation (11 patients). Each group was also divided into subgroups based on etiology - posttraumatic and nontraumatic. The AOFAS and VAS scales were compared in the preoperative and postoperative periods. It was found that screw fixation was more effective in the treatment of late stages of osteoarthritis (OA) of the ankle during the postoperative period. Comparison of the AOFAS and VAS scales showed no significant differences between the groups in the preoperative period (p = 0.838; p = 0.937). After 6 months, the results were better in the screw fixation group (p = 0.042; p = 0.047). Complications were observed for a third of the patients (10 patients). 6 patients had pain in the operated limb (4 patients in the Ilizarov apparatus group). Three patients in the Ilizarov apparatus group developed a superficial infection, and one developed a deep infection. Different etiology did not affect the postoperative efficacy of arthrodesis. The choice of the type of should be related to a clear protocol for the presence of complications. When choosing the type of fixation for arthrodesis, a patient's condition as well as a surgeon's preferences should be taken into account.

Outcomes of Early Weight Bearing in Displaced Intra-articular Calcaneus Fractures Treated with Screws-Only Fixation Technique

Background

Displaced intraarticular calcaneus fracture indicates surgical treatment. The current trend is open reduction and internal fixation with a plate or multiple screws through the sinus tarsi approach. Most postoperative protocols are prolonged non-weight bearing that causes a high socioeconomic burden. This study aims to determine the safety of the early weight-bearing protocol of screws-only fixation in calcaneal fracture.

Materials and Methods

Evaluate displaced intraarticular calcaneus fractures treated with screws-only technique via the sinus tarsi approach in our institution. The first group, from July 2017 to December 2018, allowed patients to start partial weight bearing as tolerated at 4 weeks after surgery. The second group prospectively from January 2019 to March 2020, which assign patients to keep non-weight bearing for 8 weeks. The functional outcomes (Thai Foot and ankle ability measure subjective form, FAAM) were measured 6 months after surgery. The radiographic outcome (Bohler's angle and Gissane angle) was measured on the first day postoperative and 6 months follow-up, and the changes in these angles were recorded.

Results

There were 28 patients in each group. The outcomes were collected and compared by a T-test. In the early weight-bearing group, The FAAM, Bohler's angle loss, and Gissane's angle change were 76.4 ± 14.8, 2.4 ± 3.5, and 6.6 ± 7.8, respectively. In the delayed weight-bearing group, The FAAM, Bohler's angle loss, and Gissane's angle change were 81 ± 14.8, 2 ± 1.8 and 2.6 ± 6.1, respectively. There was no statistically significant difference in FAAM score, Bohler's angle loss, and Gissane's angle change between early and delayed weight-bearing groups.

Conclusion

Screws fixation in calcaneal fracture may be safe to allow early weight-bearing protocol.

Plate versus screws fixation for the posterior malleolar fragment in trimalleolar ankle fractures

BACKGROUND

The fixation methods of posterior malleolar fracture (PMF) in trimalleolar ankle fractures is still controversial. We aim to compare clinical and radiological outcomes between plate fixation and screws fixation for PMF in trimalleolar ankle fractures.

METHODS

Literature search was performed through PubMed, EMBASE, Cochrane Library and CNKI database from databases inception to May 2022 to identify randomized controlled trial (RCT) and comparative clinical study in English or Chinese. A meta-analysis was performed using RevMan 5.1 software, and systematic review was performed when the data extracted from included studies could not be synthesized.

RESULTS

Two RCTs and six cohort studies were included. The meta-analysis results showed that articular step-off or gap in plate fixation was superior to antero-posterior screws fixation (RR = 0.28; 95%CI: 0.11, 0.76; P = 0.01). there were no significant differences in American Orthopaedic Foot & Ankle Society scores (MD = -0.19; 95%CI: -2.43, 2.05; P = 0.87), arthritis (RR = 1.67; 95%CI: 0.61, 4.55; P = 0.32), infection and total complication (RR = 1.42; 95%CI: 0.89, 2.25; P = 0.14).

CONCLUSION

Plate fixation might have better articular step-off or gap, compared with "A to P" screws fixation for the posterior malleolus in trimalleolar ankle fractures. Screw fixation could achieve shorter surgical time than plate fixation. However, no significant differences were found in AOFAS scores, arthritis, infection, sural nerve injury and total complication during the comparisons.

A windows technique for sustentaculum tali screw fixation using the sinus tarsi approach for calcaneal fractures: a cadaveric study

INTRODUCTION

The minimally invasive approach for displaced intra-articular calcaneal fractures is significantly reducing postoperative wound complications. One minimally invasive method, the sinus tarsi approach (STA) has been increasingly widely used. STA is, however, challenging due to its technical demands and the risk of injury to the sural nerve (SN). The purpose of this study was to identify the SN and its branches including their anatomical relationship to the STA as well as to describe an anatomical windows technique for STA including determination of the safe angle for screw insertion into the sustentaculum tali fragment.

METHODS

Thirty-two adult cadaveric legs were disarticulated at the knee and unpaired. STA was performed on each specimen. The anatomy and distribution of the sural nerve and its branches were identified in relation to the incision. Three surgical windows were identified and selected. Kirshner wires were inserted in pairs via each of the windows towards the center of the sustentaculum tali. The safe angle for wire insertion in relation to the SN or its branches was then measured as well as the appropriate intraoperative drilling angle.

RESULTS

The plantar branch presented in the distal window in none of the samples, while the dorsal branches presented in 37.5% and the main SN presented in only 6.25%. In the middle window, the dorsal branch presented most often (43.75%) followed by the plantar branch (25.00%) and the SN (21.88%). In the proximal window, the SN presented in 100% of the samples, while the dorsal branch presented in none and the plantar branch presented in about 15.63% of the specimens. All three windows had their own acceptable average angle for screw insertion towards the sustentaculum tali.

CONCLUSIONS

The distal window is the safest for surgical approach and for calcaneal surgery screw fixation in terms of avoiding sural nerve injury. In addition, that window provides a wide working angle for screw fixation.

Finite element analysis of screw fixation durability under multiple boundary and loading conditions for a custom pelvic implant

Despite showing promising functional outcomes for pelvic reconstruction after sarcoma resection, custom-made pelvic implants continue to exhibit high complication rates due to fixation failures. Patient-specific finite element models have been utilized by researchers to evaluate implant durability. However, the effect of assumed boundary and loading conditions on failure analysis results of fixation screws remains unknown. In this study, the postoperative stress distributions in the fixation screws of a state-of-the-art custom-made pelvic implant were simulated, and the risk of failure was estimated under various combinations of two bone-implant interaction models (tied vs. frictional contact) and four load cases from level-ground walking and stair activities. The study found that the average weighted peak von Mises stress could increase by 22-fold when the bone-implant interactions were modeled with a frictional contact model instead of a tied model, and the likelihood of fatigue and pullout failure for each screw could change dramatically when different combinations of boundary and loading conditions were used. The inclusion of additional boundary and loading conditions led to a more reliable analysis of fixation durability. These findings demonstrated the importance of simulating multiple boundary conditions and load cases for comprehensive implant design evaluation using finite element analysis.

Comparison of screw versus locking plate fixation via sinus tarsi approach for displaced intra-articular calcaneal fractures

BACKGROUND

The optimal treatment of displaced intra-articular calcaneal fractures (DIACF) is controversial. This study compared the fixation stability of screws and locking plates in DIACF treated via the sinus tarsi approach (STA).

METHODS

We retrospectively evaluated 118 DIACF cases treated via STA and extracted data that could affect treatment outcomes. Loss of Böhler's angle after surgery was measured to compare fixation stability.

RESULTS

The loss of Böhler's angles was significantly smaller in the locking plate group than in the screw group (2.6 ± 2.7º vs. 5.6 ± 5.3º, P < 0.01). There was no difference in the clinical outcomes between the groups. On multivariate logistic regression analysis, screw fixation was significantly associated with loss of Böhler's angle by> 10º (odds ratio, 8.63; 95% confidence interval, 1.16-64.4; P < 0.05).

CONCLUSIONS

Locking plate fixation is more reliable than screw fixation for preventing correction loss in DIACF treated via STA.

LEVEL OF EVIDENCE

III.

Clinical outcome of arthroscopic suture versus screw fixation in tibial avulsion of the anterior cruciate ligament in skeletally mature patients

BACKGROUND

Tibial eminence fracture is an intra-articular fracture of bony attachment of ACL. The displaced fragment could hinder the mobility of the knee and may lead joint instabilty; therefore, requires fixation. Arthroscopic suture and screw fixation are the widely used surgical modalities for eminence fractures of the tibia. Past studies have not yet depicted the superiority of one method over the other. Through this cohort study, comparison of the clinical and functional outcomes of these two surgical methods was done.

METHODS

A prospective, randomized, interventional study was conducted from December 2019 to January 2022 for comparing the clinical outcome of arthroscopic pull through suture fixation and arthroscopic antegrade cancellous screw fixation in skeletally mature individuals. Ninety patients (45 in each group) were randomly assigned and treated with the above two methods. A comprehensive clinical analysis was done after nine months of surgery for assessment of functional outcome, ligament laxity, range of motion, and complications if any.

RESULTS

65.55% of anterior tibial eminence fractures were caused by road traffic accidents followed by sports injuries (28.88%). The postoperative mean subjective IKDC score in the suture group was 91.36 and for the screw fixation group was 85.71 (p = 0.001). After nine months of surgery, the mean LKS was 91.96 in patients treated with suture fixation and 86.00 in patients treated with screw fixation (p = 0.001). Pivot shift grading was grade 3 in one patient of the suture group and in three patients of the screw group (p = 0.319). Seven patients who had screw fixation required re-surgery for removal of the implant; however, no such complication was seen in the suture fixation group.

CONCLUSION

Arthroscopic pull-through suture fixation of tibial avulsion of ACL in skeletally mature patients seems to be a superior intervention over arthroscopic screw fixation with the benefits of better clinical and functional outcomes and decreased chances of re-surgery.

Biomechanical evaluation of compression buttress screw and medial plate fixation for the treatment of vertical femoral neck fractures

OBJECTIVE

To compare the biomechanical properties of compression buttress screw (CBS) fixation with three plate fixation methods for the treatment of vertical femoral neck fractures (FNFs).

METHODS

A total of forty synthetic femoral models with simulated Pauwels type III fractures (angle of 70°) were equally assigned to one of four fixation groups: CBS fixation, anteromedial plate fixation (AMP), medial buttress plate fixation (MBP) and medial buttress plate fixation without proximal screw (MBPw). Within each group, half of the specimens were randomly assigned to two loading settings, an axial compression loading test and a hip-flexion torsion test.

RESULTS

There were no significant differences in axial load to failure, axial stiffness, torsional strength, or torsional stiffness when comparing CBS with MBP (p>0.05). In the axial compression loading test, both CBS and MBP showed higher load to failure and axial stiffness than MBPw (p<0.05). In torsional testing, AMP exhibited superior torsional strength and torsional stiffness than both MBPw and MBP (all p<0.05) and a higher torsional strength than CBS fixation (p<0.05). There were no significant differences in torsional stiffness between the CBS and AMP fixation groups (p>0.05).

CONCLUSION

The biomechanical parameters of CBS fixation are comparable to that of AMP and MBP, and demonstrate superior axial stiffness than MBPw fixation. Although the CBS method for surgical fixation of vertical FNF holds promise as a less invasive surgical technique than plate fixation with similar biomechanical assessments, further clinical evaluation is warranted.

A True Percutaneous Anterior Odontoid Screw Fixation: The Results of 42 Cases by a Single Surgeon

OBJECTIVE

This study aimed to analyze a clinical series of odontoid fractures treated with true percutaneous anterior odontoid screws. The technique we used is different from the traditional approach of using blunt dissection to arrive at the anterior surface of the vertebral body.

METHODS

Between 2004 and 2021, forty-two patients underwent anterior screw fixation of the odontoid process using the true percutaneous technique without dissection among the fascial planes. Instead, we pressed from the medial border of the sternocleidomastoideus muscle with our second and third fingers to feel the vertebrae under the skin. Thus, the carotid artery is pushed laterally, the trachea-esophageal complex is moved medially, and when no esophagus, great vessels, etc., can be felt under our fingers; we have reached the anterior surface of the spine. Advancing the Jamshidi needle between the fingers causes it to pass only through the fascial layers. The absence of a gap between the dilatation tubes prevents any tissue from escaping into the tubes.

RESULTS

We had no intraoperative complications, such as esophageal, tracheal, or carotid injury. One patient required screw revision. In total, 5 patients died during the follow-up period, and 3 were lost to follow-up. There was no residual neck pain in our cohort, and no instability was noted on flexion-extension radiographs, even in ten patients without solid bone fusion.

CONCLUSIONS

True percutaneous anterior odontoid screw fixation is a safe and reliable procedure for treating odontoid fractures. The fibrous union of odontoid fractures provides as much stability as a solid bone fusion.

Screw fixation in the treatment of displaced intra-articular calcaneus fractures: a systematic review protocol

BACKGROUND

The Calcaneus is the largest bone of the foot and the most frequent tarsal bone to be fractured. Overall, it causes round about 10 cases per 100,000 residents per year mainly in men. Especially displaced intra-articular calcaneus fractures often have early and late complications and its associated disability. There are various strategies for the treatment of displaced intra-articular calcaneus fractures, but the gold standard is still subject of a long-standing controversy. Minimally invasive procedures became more common in an attempt to reduce the high rate of complications associated with open reduction and internal fixation. With the increase in minimally invasive techniques, screw fixation also gained in significance. The current literature does not sufficiently elucidate whether the screw fixation is superior to other treatment options especially in relation to adverse events, health-related quality of life and postoperative pain. This study aims to investigate benefits and harms of treating displaced intra-articular calcaneus fractures (types II, III and IV according to Sanders) with screw fixation in adults.

METHODS

A systematic review will be conducted based on the principles described in the Cochrane Handbook. We will include adults with displaced intra-articular calcaneus fractures of Sanders type II, III and IV. The surgical method of screw fixation shall be compared to other surgical interventions to stabilise calcaneus fractures. Primary outcomes are serious adverse events, health-related quality of life and postoperative pain level. MEDLINE, CENTRAL, CINAHL, Web of Science and bibnet.org, ClinicalTrial.gov and the World Health Organization International Clinical Trials Registry Platform (ICTR) will be searched. Screening and data extraction will be performed by two authors independently. A third author will arbitrate disputes. Risk of Bias will be assessed with the Cochrane tool. Meta-analysis will be performed if participants, interventions, comparisons and outcomes are sufficiently similar to ensure a result that is clinically meaningful.

DISCUSSION

Due to the increasing use of minimally invasive techniques and the increasing use of screw fixation instead of open reduction and plate fixation, it is important to analyse the benefits and harms of screw fixation for calcaneus fractures. Screw fixation could, in the future, help to operate in a less invasive and tissue preserving manner while still achieving an adequate functional result for the patient SYSTEMATIC REVIEW REGISTRATION: CRD42021244695.

How to fix a tibial tubercle osteotomy with distalisation: A finite element analysis

BACKGROUND

Antero-medialisation osteotomy combined with a distalisation procedure may require a more stable fixation as the osteotomy fragment loses both proximal and distal support. This finite element analysis aimed to compare the mechanical behaviour of different fixation techniques in tibial tubercle antero-medialisation osteotomy combined with distalisation procedure.

METHODS

Tibial tubercle osteotomy combined with distalisation was modelled based on computerised tomography data, which were acquired from a patient with patellar instability requiring this procedure. Six different fixation configurations with two 3.5-mm cortical screws (1), two 4.5-mm cortical screws (2), three 3.5-mm cortical screws (3), three 4.5-mm cortical screws (4), three 3.5-mm screws with 1/3 tubular plate (5), and four 3.5-mm screws with 1/3 tubular plate (6) were created. A total of 1654 N of force was applied to the patellar tendon footprint on the tibial tubercle. Sliding, gap formation, and total deformation between the osteotomy components were analyzed.

RESULTS

Maximum sliding (0.660 mm), gap formation (0.661 mm), and displacement (1.267 mm) were seen with two 3.5-mm screw fixation, followed by two 4.5-mm screws, three 3.5-mm screws, and three 4.5-mm screws, respectively, in the screw-only group. Overall, the minimum displacement was observed with the four 3.5-mm screws with 1/3 tubular plate fixation model.

CONCLUSIONS

Plate fixation might be recommended for tibial tubercle antero-medialisation osteotomy combined with distalisation procedure because it might allow early active range of motion exercises and weight-bearing.

[Preliminary finite element analysis of percutaneous screw fixation of Schatzker typeⅠ tibial plateau fracture]

OBJECTIVE

To compare the stress changes and displacement of SchatzkerⅠ tibial plateau fracture screw fixation model under different loads.

METHODS

The three-dimensional CT images of the knee joint of a healthy male volunteer were selected to establish the three-dimensional model, and then the Schatzker I tibial plateau fracture model and screw fixation model were established. Simulate the two stress conditions of each model when standing on one foot and standing on two feet, the stress changes of tibia, split bone block and cannulated screw and the displacement between fractures were observed and compared.

RESULTS

When standing on both feet, the model with the largest stress value of hollow screw, split bone block and tibia was the improved triangular support fixation model group, and the model with the largest displacement in the Z-axis direction of the overall model was the conventional screw fixation model group. When standing on one foot, the model with the largest stress value of hollow screw, split bone block and tibia was the improved triangular support fixation model group, and the model with the largest displacement in the Z-axis direction of the overall model was the conventional screw fixation model group.

CONCLUSION

The lowest stress value of split bone block and screw is the palisade screw fixation model, and the largest is the improved triangular support fixation model. The Z-axis displacement of the conventional screw fixation model is the largest, and the displacement of the fence screw model is equivalent to that of the improved triangular support screw model.

Combination of Percutaneous Screw Fixation and Cementoplasty for Lytic Bone Metastases: Feasibility, Safety and Clinical Outcomes

OBJECTIVE

To evaluate feasibility, safety and efficacy of a combination of screw fixation and cementoplasty for pathologic bone fracture.

METHODS

In this single-center prospective study, all consecutive percutaneous screw fixations under assisted CT guidance for palliation and fracture treatment of pathologic bone fracture were reviewed from July 2019 to February 2021. The primary outcome measure was the procedures' technical success, defined as the correct placement of the screw(s), without any complications. Secondary outcome measures were the safety, the procedures' early analgesic effects and impacts on quality of life at 4 weeks.

RESULTS

Technical success was achieved in 11/11 procedures (100%) among 11 patients. No major complications attributable to the procedure were noted. The mean pain scored significantly decreased at the initial follow-up: 8.0 ± 2.7 versus 1.6 ± 2.5 (p < 0.05). Opioid doses were statistically lower after procedure: 70.9 ± 37 versus 48.2 ± 46 mg/day (p < 0.05). The mean EQ5D score had significantly increased by the early post-procedure consultation: 42.5 ± 13.6 vs 63.6 ± 10.3 (p < 0.05).

CONCLUSION

Combination of percutaneous screw fixation and cementoplasty for pathologic bone fracture is feasible and safe. It is efficient to reduce pain, decrease the consumption of opioids and improve the quality of life at 4 weeks after the procedure.

Subtalar arthrodesis using a single compression screw: a comparison of results between anterograde and retrograde screwing

INTRODUCTION

The primary objective of this study was to compare the radiological and clinical results of anterograde and retrograde screwing in subtalar arthrodesis using a single compression screw. The secondary objective was to evaluate the subjective results and consolidation of this procedure. The hypotheses were that isolated screw fixation was sufficient to achieve good consolidation and that there was no difference between the two techniques with a similar rate of bone fusion.

METHODS

This is a monocentric, retrospective, radio-clinical study based on 99 patients (101 feet), 58 males and 41 females, with an average age of 64 years. The main aetiology was post-traumatic osteoarthritis, which represented 51% of cases. Two groups were formed: group A (52 feet) consisting of fixed arthrodesis with ascending (retrograde) screwing and group D (49 feet) consisting of fixed arthrodesis with descending (anterograde) screwing. The two groups were statistically comparable in terms of demographic data as well as aetiologies and comorbidities. Arthrodeses which were not fused at 6 months were reassessed at one year and in the event of any radio-clinical doubt regarding consolidation, an additional CT scan was prescribed. Average post-operative follow-up was 11 ± 5 years (2-27 years).

RESULTS

Ninety-two arthrodeses (93%) were fused at one year and 9 were considered to be in non-union, 5 (9.8%) in group A, and 4 (8.3%) in group D. We recorded 30 complications, 22 of which were due to a conflict with the screw head, 18 (34.5%) in group A and 4 (8.3%) in group D (p = 0.03). Conflict between the screw head and the heel led to the removal of the screw after consolidation of the arthrodesis. The clinical results were evaluated using Odom's criteria. Nine per cent of patients described their results as excellent, 29% as good, 51% as satisfactory and 11% found the result to be poor.

CONCLUSION

The fusion rate for isolated compression screw arthrodesis is good, and there is no difference between anterograde and retrograde screws. However, the discomfort caused by the screw head being insufficiently embedded in the retrograde group led to a non-negligible number of additional surgeries to remove the screw.

Implications of the Overlapping Degree Between Proximal Fibula and Tibia for Placing the Optimal Syndesmotic Screw: A Virtual Cadaveric Study

BACKGROUND

To determine the optimal direction of the syndesmotic screw and to introduce a consistent landmark for practical application by analyzing three-dimensional (3D) modeling and virtual implantation.

METHODS

A total of 105 cadaveric lower legs (50 males and 55 females; average height, 160.6 ± 7.1 cm) were used to reconstruct a 3D model by using the Mimics® software and the joint morphology was evaluated. Syndesmotic cylinders (Ø3.5 mm/Length 100 mm) were transversely placed in the proximal end of the incisura fibularis for simulating screw fixation. The tibial proximal cylinder, which was tangent to the posterior tibial condyles, was traced and the angle between the two cylinders was measured as the tibial torsion angle (TTA). After rotating the syndesmotic cylinder parallel to the ground, the overlapping degree between the proximal fibula and tibia was assessed as a radiologic indicator.

RESULTS

Concerning tibial torsion, the TTA was an average of 36.7° (range, 17.2°-54.4°; SD, 8.78) When the syndesmotic cylinder was rotated to be parallel to the ground, the proximal fibula had nonlinear or linear overlap with the lateral border of the tibia, regardless of the joint morphology. In this non-overlapping view, three Weber's indices for normal fibular length could be better visualized than the mortise view.

CONCLUSION

The syndesmotic cylinder in the proximal end of the incisura fibularis could be consistently placed parallel to the ground by internally rotating the tibia until there was a nonlinear or linear overlap between the proximal fibula and the tibia, regardless of the joint morphology.

Systematic review of sacroiliac joint motion and the effect of screw fixation

BACKGROUND

Pelvic injuries that disrupt the sacroiliac joints often require surgical intervention to restore stability. Quantitative characterization of sacroiliac motion in response to physiologic loading provides important metrics of adequate fixation in the evaluation of newly emerged fixation techniques. The objective of this study was to systematically review and evaluate biomechanical evidence on the motion of the sacroiliac joint in its normal, destabilized, and stabilized states.

METHODS

We searched the PubMed database for studies available until June 2020 using keywords: sacroiliac, biomechanic*, and fixation. Publications of any in vivo or in vitro biomechanical study that included measurements of the range of motion at the sacroiliac joint were considered.

FINDINGS

We identified and screened 176 total records, and 13 articles of them met inclusion criteria and were used in this review. The average sacroiliac joint range of motion of the intact pelvis was 1.88° in flexion/extension, 0.85° in lateral bending, 1.26° in axial rotation. Of the 13 studies, four reported sacroiliac motion from a destabilized state, while seven reported the motion after stabilization. A forest plot of the stabilized data set in flexion/extension showed that while the heterogeneity was poor, the weighted effect size of the changes from the intact state to the stabilized state was 0.0%.

INTERPRETATION

Quantitative evidence on sacroiliac joint motion relating to pelvic injuries or fixation is limited. Our results indicate that the pooled intact range of motion from the literature may serve as a viable reference to quantify the effectiveness of new stabilization techniques.

LEVEL OF EVIDENCE

Level V, systematic review.

STUDY TYPE

Therapeutic- investigating the results of a treatment.

The study of screw placement parameters for Ogawa type I acromial fractures by 3D simulation

Background

Acromial fractures are rare and there is no consensus on fixation, but an increasing number of studies have reported using two screws to fix Ogawa type I acromial fractures. The objective of this study was to obtain the ideal length, diameter, insertion point, and angle of the screw using a novel 3D simulation.

Methods

The scapular CT data of 100 individuals were obtained to reconstruct 3D models. The transparency of the 3D model was then downgraded along the axial perspective (the view perpendicular to the cross section of the acromion axis) to find the maximum translucent area. Two virtual screws were placed at the anterior edge of the acromion until they penetrated the posterior cortical bon. The largest diameters and lengths of the screw were measured, and the direction and insertion point of the screw were observed.

Results

The mean maximum lengths of the medial and lateral screws were 43.33 ± 6.17 mm and 39.23 ± 6.01 mm, respectively. The mean maximum diameters of the medial and lateral screws were 4.71 ± 1.23 mm and 4.97 ± 1.07 mm, respectively. Differences in screw length, diameter, and insertion point between males and females were found. The differences in screw angle between sexes were not statistically significant.

Conclusions

Based on a 3D model test, we recommend the size, entry points, and angles of screws for Ogawa type I acromial fractures, providing valuable guidance for clinical work. More accurate screw parameters can be obtained preoperatively by establishing an individualized 3D model.

Augmented cerclage wire improves the fixation strength of a two-screw construct for humerus split type greater tuberosity fracture: a biomechanical study

Background

Poor functional outcome can result from humeral greater tuberosity (GT) fracture if not treated appropriately. A two-screw construct is commonly used for the surgical treatment of such injury. However, loss of reduction is still a major concern after surgery. To improve the biomechanical strength of screw fixation in GT fractures, we made a simple modification of the two-screw construct by adding a cerclage wire to the two-screw construct. The purpose of this biomechanical study was to analyze the effect of this modification for the fixation of GT fractures.

Materials and methods

Sixteen fresh-frozen human cadaveric shoulders were used in this study. The fracture models were arbitrarily assigned to one of two fixation methods. Group A (n = 8) was fixed with two threaded cancellous screws with washers. In group B (n = 8), all screws were set using methods identical to group A, with the addition of a cerclage wire. Horizontal traction was applied via a stainless steel cable fixed directly to the myotendinous junction of the supraspinatus muscle. Displacement of the fracture fixation under a pulling force of 100 N/200 N and loading force to construct failure were measured.

Results

The mean displacements under 100 N and 200 N traction force were both significantly decreased in group B than in group A. (100 N: 1.06 ± 0.12 mm vs. 2.26 ± 0.24 mm, p < 0.001; 200 N: 2.21 ± 0.25 mm vs. 4.94 ± 0.30 mm, p < 0.001) Moreover, the failure load was significantly higher in group B compared with group A. (415 ± 52 N vs.335 ± 47 N, p = 0.01),

Conclusions

The current biomechanical cadaveric study demonstrated that the two-screw fixation construct augmented with a cerclage wire has higher mechanical performance than the conventional two-screw configuration for the fixation of humeral GT fractures.

Trial registration

Retrospectively registered.

Achieve Closed Reduction of Irreducible, Unilateral Vertically Displaced Pelvic Ring Disruption with an Unlocking Closed Reduction Technique

OBJECTIVE

To be able to treat irreducible unilateral vertically displaced pelvic ring disruption (UVDPRD) using closed reduction, we introduced a technique named Unlocking Closed Reduction Technique (UCRT) and evaluated its effectiveness with improved pelvic closed reduction system (PCRS).

METHODS

A retrospective study was performed in our department. Between January 2014 and December 2017, 43 patients whose UVDPRD were not successfully reduced using transcondylar traction. Subsequently, they were treated with UCRT using improved PCRS. The study included 19 male and 24 female patients, with a mean age at the time of the operation of 46.2 years. During surgery, operation time and blood loss were recorded. Post-surgical reduction quality was evaluated using Matta scoring criteria and patient lower-extremity functional outcome was evaluated using Majeed functional scoring criteria.

RESULTS

When used with improved PCRS, UCRT achieved pelvic reduction in all 43 cases of irreducible UVDPRD with postoperative pelvic reduction quality rated excellent and good for 42/43 (97.6%) patients according to the Matta scoring criteria (Matta Score < 10 mm). While no post-surgical complications emerged as the direct result of UCRT in this cohort of patients, 8/37 patients who were treated with subcutaneous supra-acetabular pedicle screw internal fixation (INFIX) for anterior ring fixation developed lateral femoral cutaneous nerve injury but recovered 6 months postoperatively. No revision surgery was performed on any of the recruited patients. All patients' lower-extremity functionality was rated excellent with an average Majeed function score of 94.3 during the last follow-up at an average of 41.6 months postoperatively.

CONCLUSION

With excellent surgical and functional outcomes in patients with irreducible UVDPRD, improved PCRS-assisted UCRT proved to be a safe and effective method for the treatment of irreducible UVDPRD.

A new tool in percutaneous anterior odontoid screw fixation

BACKGROUND

Percutaneous anterior odontoid screw fixation for odontoid fractures remains challenging due to the complex anatomy of the craniocervical junction. We designed a new guide instrument to help with the placement of guide wire, which have achieved satisfying surgical results. The objective of this study is to evaluate the safety and efficacy of this new tool in percutaneous anterior odontoid screw fixation.

METHODS

Twenty-nine patients with odontoid fracture were retrospectively evaluated. All patients underwent percutaneous anterior odontoid screw fixation with the traditional guide instrument (n = 13) or the new guide instrument we designed (n = 16). The following clinical outcomes were compared between the two groups: operation time, radiograph times, incision length, blood loss, postoperative hospitalization, postoperative complications, bony union, fixation failure, and reoperation. Radiographs or CT scans were performed at 3, 6 and 12 months after surgery.

RESULTS

There were no significant differences in preoperative demographic data between the two groups. The operation time (56.62 ± 8.32 Vs 49.63 ± 7.47, P = 0.025) and radiograph times (26.54 ± 6.94 Vs 20.50 ± 5.02, P = 0.011) of the designed guide instrument group were significantly lower than those of the traditional guide instrument group. There were no significant differences in incision length (16.08 ± 3.07 Vs 15.69 ± 2.73, P = 0.720), blood loss (16.08 ± 4.96 Vs 17.88 ± 5.98, P = 0.393), postoperative hospitalization (7.15 ± 1.91 Vs 6.88 ± 2.36, P = 0.734), postoperative complications (7.7% Vs 12.5%, P = 1), and bony union (92.3% Vs 93.8%, P = 1) between the two groups. No fixation failure or reoperation occurred in either group.

CONCLUSIONS

The top of our designed guide instrument is a wedge-shaped tip with 30° inclination, which has a large contact area with the anterior surface of the cervical vertebra. According to our retrospective study, the guide instrument can reduce the operation time and radiograph times. It has potential clinical value, which needs further testing with a higher level of research design.

A guideline for screw fixation of coracoid process base fracture by 3D simulation

BACKGROUND

Fractures of the base of the coracoid process are relatively rare, but an increasing number of studies have reported using screws to fix coracoid process base fractures. This study was performed to simulate the surgical procedure and obtain the ideal diameter, length, insertion point and angle of the screw from a 3-D axial perspective in Chinese patients.

METHODS

We randomly collected right scapula computed tomography (CT) scans from 100 adults. DICOM-formatted CT scan images were imported into Mimics software. A 3D digital model of the right scapula was established. Two virtual cylinders representing two screws were placed from the top of the coracoid process to the neck of the scapula and across the base of the coracoid process to fix the base of the coracoid process. The largest secure diameters and lengths of the virtual screws were measured. The positions of the insertion points and the directions of the screws were also examined.

RESULTS

The screw insertion safe zone can exhibit an irregular fusiform shape according to the reconstructed scapula model. The mean maximum diameters of the medial and lateral screws were 7.08 ± 1.19 mm and 7.34 ± 1.11 mm, respectively. The mean maximum lengths of the medial and lateral screws were 43.11 ± 6.31 mm and 48.16 ± 6.94 mm, respectively. A screw insertion corridor with a diameter of at least 4.5 mm was found in all patients. We found sex-dependent differences in the mean maximum diameters and maximum lengths of the two screws. The positions of the two insertion points were statistically different across sexes.

CONCLUSIONS

The study provides a valuable guideline for determining the largest secure corridor for two screws in fixing a fracture at the base of the coracoid process. For ideal screw placement, we suggest individualised preoperative 3D reconstruction simulations. Further biomechanical studies are needed to verify the function of the screws.

Long-Term Efficacy of Screw Fixation vs Hemiarthroplasty for Undisplaced Femoral Neck Fracture in Patients over 65 Years of Age: A Systematic Review and Meta-Analysis

Objective

To compare the long‐term efficacy of screw fixation and hemiarthroplasty in elderly patients with undisplaced femoral neck fractures.

Methods

We searched Cochrane Library, EMBASE, and MEDLINE from inception to 10 June 2020 to identify studies about undisplaced femoral neck fracture in elderly patients over 65 years of age. The included studies were assessed by two researchers according to the Cochrane risk‐of‐bias criteria and Newcastle–Ottawa Scale. Meta‐analysis was performed with Revman 5.3 software. The odds ratios (OR) and mean differences (MD) were used to compare dichotomous and continuous variables.

Results

A total of 750 patients were included in this meta‐analysis. In elderly patients, undisplaced femoral neck fracture treated with hemiarthroplasty had a lower implant‐related complication rate (OR, 4.05 [95% CI, 2.38 to 6.89]; P < 0.00001; I² = 0), lower reoperation rate (OR, 4.88 [95% CI, 2.84 to 8.38]; P < 0.00001; I² = 0), and superior Harris score (WMD, −5.05 [95% CI, −7.30 to −2.80]; P < 0.0001; I² = 0) in the early postoperative period. Although screw fixation was associated with shorter operative time (WMD, −36.22 [95% CI, −50.72 to −21.73]; P < 0.00001; I² = 98%) and less blood loss (WMD, −165.84 [95% CI, −209.29 to −122.38]; P < 0.00001; I² = 96%), there was no significant difference in long‐term mortality (OR, 0.65 [95% CI, 0.28 to 1.48]; P < 0.31; I² = 75%) between these two treatments.

Conclusion

In elderly patients with undisplaced femoral neck fractures, hemiarthroplasty provided a lower implant‐related complication rate, lower reoperation rate, superior hip function without increased long‐term mortality. Hemiarthroplasty should be recommended as a better alternative in such patients compared with multiple cannulated screws.

Percutaneous Image-Guided Anterior Screw Fixation of the Odontoid Process

PURPOSE

To describe the technique of percutaneous image-guided anterior screw fixation of the odontoid process in five patients using hydrodissection of the jugulo-carotid and pre-vertebral spaces.

METHODS AND MATERIALS

Between 03/2018 and 03/2020, five patients from two university hospitals underwent a percutaneous image-guided anterior screw fixation of the odontoid process for one pathological fracture, two impending fractures and two traumatic fractures of the dens. Technical success was defined as a satisfactory positioning of the screw in the odontoid. Detailed data with the number and type of needles required, the time to perform hydrodissection, the volume of fluid used, the time for bone access, the size and lengths of the screws used, technical success, complications, clinical outcomes and follow-up were retrospectively assessed.

RESULTS

Technical success was achieved in 100% (5/5 cases), with a mean volume of hydrodissection of 218 ± 8.4 mL (range 210-230). Mean total procedure time was 112 ± 34 min (range 70-160). The lengths of the screws ranged from 30 mm to 55 mm. Additional cementoplasty was performed in the three malignant cases. VAS scores dropped on a 10-point scale from mean 5.8 ± 2.2 pre-procedure to 0.8 ± 0.4 after the procedure. No major complication occurred.

CONCLUSION

Percutaneous image-guided anterior screw fixation of the odontoid process using hydrodissection of the jugulo-carotid and pre-vertebral spaces is technically feasible and seems safe.

Jones Fracture in the Nonathletic Population

Fractures of the proximal fifth metatarsal are common injuries with a unique history. Treatment of these fractures is controversial partly because of confusion regarding fracture subtype nomenclature. Today "Jones fracture" refers to proximal fifth metatarsal fracture in zones 2 or 3. Zone 2 fractures are acute injuries, and their optimal treatment is unclear. Zone 3 fractures commonly occur in the presence of a chronic stress reaction. Because of poor healing potential, zone 3 fractures typically require operative treatment. Zone 1 fractures have excellent healing potential and may be treated nonoperatively with a weightbearing as tolerated protocol.

Arthroscopic treatment of a one-fourth anteroinferior glenoid comminuted fracture-dislocation with concomitant three-part complex proximal humerus fracture in a middle-aged man: a case report

INTRODUCTION

Proximal humeral fracture-dislocations can occur in high-energy traumas. This injury can be accompanied by a glenoid fracture; however, it is a rare type of complex injury in patients aged under 60 years.

MATERIALS AND METHODS

A 53-year-old man presented with a three-part fracture-dislocation of the proximal humerus and a severely comminuted glenoid fracture. For the glenohumeral dislocation and proximal humeral fracture, we performed closed reduction using a threaded Steinman pin and fixation with percutaneous cannulated screws. Using arthroscopy, while maintaining humeral traction with the Steinman pin, the intra-articular glenoid fragments were reduced and then fixed with a buttressing headless screw and one suture anchor. After a 6-week immobilization with a shoulder spica cast, rehabilitation was initiated.

RESULTS

We confirmed bony union of the fracture sites after 6 months post-surgery. The patient showed excellent clinical outcomes with a nearly full range of motion without instability CONCLUSIONS: We reported a successful outcome for a complex proximal humeral fracture involving the glenoid using closed reduction and fixation for the proximal humeral fracture and arthroscopic reduction and fixation for the comminuted anteroinferior glenoid fracture.

Timing of osteosynthesis of fractures in children changes the outcome

PURPOSE

The search for optimal treatment strategies for fractures in children that require osteosynthesis is controversial and is still being debated. A major factor that has been under discussion is the impact of the timing of surgery: the time delay between the trauma and the operation, as well as the duration of the surgical procedure, and the time of day that the operation is performed are potential factors that might influence the outcome. Therefore, the aim of our study was to investigate the influence of these factors on the outcome after osteosynthesis of diverse fractures of the extremities in children.

METHODS

In a retrospective study, 387 patients aged 1-18 years who presented with fractures of the extremities that underwent surgery were included. Patient records including radiological studies were analyzed. The follow up period lasted at least 12 months or until recovery. Statistical significance was set at an alpha level of P ≤ 0.05.

RESULTS

Delayed surgery, as well as a prolonged duration of surgery, and the mode of transportation of the patient significantly were related to a higher rate of complications. However, in this study, the complication rate was not found to be influenced by the mode of reduction of the fracture, or the time of day or the day of the week. A further parameter that significantly changed the outcome was the mechanism of injury. However, the rate of complications was unchanged if a resident or a consulting was the performing surgeon so that a resident can safely perform the procedure in the presence of a consultant.

CONCLUSION

Timing of surgery for fractures of the extremities in children, including the time from trauma to surgery, the duration of the operation and the mode of transportation to the ER, were found to have a significant impact on the occurrence of complications in this study while the mode of reduction and the time of day did not change the outcome. Future studies with a focus on selected types of fractures are needed to further enlighten this topic.

LEVEL OF EVIDENCE

Retrospective comparative study, level III.

Stripping torques in human bone can be reliably predicted prior to screw insertion with optimum tightness being found between 70% and 80% of the maximum

AIMS

To devise a method to quantify and optimize tightness when inserting cortical screws, based on bone characterization and screw geometry.

METHODS

Cortical human cadaveric diaphyseal tibiae screw holes (n = 20) underwent destructive testing to firstly establish the relationship between cortical thickness and experimental stripping torque (Tstr), and secondly to calibrate an equation to predict Tstr. Using the equation's predictions, 3.5 mm screws were inserted (n = 66) to targeted torques representing 40% to 100% of Tstr, with recording of compression generated during tightening. Once the target torque had been achieved, immediate pullout testing was performed.

RESULTS

Cortical thickness predicted Tstr (R2 = 0.862; p < 0.001) as did an equation based on tensile yield stress, bone-screw friction coefficient, and screw geometries (R2 = 0.894; p < 0.001). Compression increased with screw tightness up to 80% of the maximum (R2 = 0.495; p < 0.001). Beyond 80%, further tightening generated no increase in compression. Pullout force did not change with variations in submaximal tightness beyond 40% of Tstr (R2 = 0.014; p = 0.175).

CONCLUSION

Screw tightening between 70% and 80% of the predicted maximum generated optimum compression and pullout forces. Further tightening did not considerably increase compression, made no difference to pullout, and increased the risk of the screw holes being stripped. While further work is needed for development of intraoperative methods for accurate and reliable prediction of the maximum tightness for a screw, this work justifies insertion torque being considerably below the maximum.Cite this article: Bone Joint Res 2020;9(8):493-500.

Risk of bony violation with standard triple screw configurations for fixation of femoral neck fractures: A preliminary computed tomography based analysis

PURPOSE

The reduction and fixation of femoral neck fractures is mainly an indirect one with intraoperative fluoroscopy being trusted for the safe containment of screws within the bony limits of the femoral neck. Radiologically undetected bony perforations may have an impact on the fracture stability and radiological outcomes that have not been studied previously. The purpose of this computed tomography (CT) based study is to analyze the safety of containment of triple screw configurations using standard 6.5 mm diameter screws for fixation of femoral neck fractures in the Indian population using a software-based analysis.

METHODS

Data from consecutive CT scans with intact proximal femur performed over a six month period were retrospectively analyzed using iPlan® BrainLab AG, Feldkirchen, Germany. The safe containment of virtual screw trajectories placed in inverted triangular and non-inverted triangular configurations for a 6.5 mm diameter screw was analyzed in intact femoral necks.

RESULTS

A total of 72 cases were considered for the final assessment. For 6.5 mm screws, the proportion for safe containment (without bony violation) of triple screw inverted triangular configuration was 75% with additional safety corridor to 1 mm around the screw trajectories and 31.94% for non-inverted triangular configuration. All male cases and 28% of female cases allowed safe placement of three 6.5 mm screw trajectories in an inverted triangular pattern with a safety margin of 1 mm around the screw. Replacement of one of the two superior 6.5 mm diameter screw trajectories with a 4.5 mm diameter trajectory resulted in 100% safe containment in female cases.

CONCLUSION

Inverted triangular configuration is a relatively safer configuration compared to the non-inverted triangular configuration. Standard triple 6.5 mm screws for fixation of femoral neck fractures carry a risk of bony violation, especially in females. A preoperative radiographic assessment to screen the cases with narrow vertical and anteroposterior extents of the femoral neck can help in reducing the risk of fluoroscopically undetected violation of the bony margins. Replacement of one of the two superior screws with a 4.5 mm diameter screw can be helpful in such cases.

The C2 Cortical Screw, an Alternative Fixation Technique for the C2 Segment During High Cervical Spine Surgery: Technical Note

BACKGROUND

For posterior fixation of C2 vertebra (the axis), several fixation techniques such as pedicle screw, laminar screw, and pars screw have been reported. A pedicle screw (PS) is considered the strongest among the techniques, but certain situations make PS fixation impossible or difficult. These include patients with a narrow C2 pedicle or high-riding vertebral artery. We introduced an alternative screw technique for C2 that addressed the aforementioned problems with safely placing it, which we termed a cortical screw (CS) for C2.

METHODS

Among a total of 28 cases using C2 CS for high cervical spine surgery, 2 cases using C2 CS were described. One patient was a 76-year old woman with a gait disturbance and myelopathic symptoms and diagnosed with C1-C2 myelopathy and translational instability. The other case was 54-year old man with posterior neck pain after traffic accident and diagnosed with C1-C2 fracture-dislocation. We used the C2 CS as an alternative technique for high cervical spine surgery in these patients and describe the ideal entry point and trajectory.

RESULTS

A postoperative computed tomography scan confirmed proper positioning of the C1 posterior arch screw and C2 CS, with satisfactory reduction of the C2 dens and adequate restoration of the C1-C2 spinal canal. The patient experienced no screw-related postoperative complications, and postoperative 1-year computed tomography images showed that solid union and good alignment of C1-2 segment was achieved.

CONCLUSIONS

C2 CS can be suitable alternative for C2 screw fixation technique in posterior high cervical spine fusion surgery.

Internal fixation of intracapsular femoral neck fractures in elderly patients: mortality and reoperation rate

BACKGROUND

A significant increase in the prevalence of intracapsular femoral neck fractures in the elderly population was reported but the best treatment is still debated.

AIM

To evaluate the mortality rate and the reoperation rate of stable neck fractures treated with cannulated screw fixation in elderly patients.

METHODS

This was a retrospective study of patients older than 60 years with a Garden I or II femoral neck fractures treated with cannulated screw fixation without capsulotomy. A total of 244 patients (246 hips) who underwent surgery between 2008 and 2018 were included. The average age at the time of surgery was 80 years (range 60-99 years). The mean ASA score was 2.64 (range 1-4). Mortality rate, complications, reoperation rate, the time elapsed between surgeries were recorded.

RESULTS

The mortality rate was 50.0%. There were 16 mortalities (6.6%) in the first-month follow-up. We observed higher mortality rates in ASA 4 (80.8%). In 22 patients (8.9%), complications after surgery were observed, and in 11 patients (4.5%) underwent conversion surgery to hemiarthroplasty at a mean of 14.6 months (range 2-48 months) after the femoral screw fixation. Two patients were treated with hardware removal and Gamma Nail for a peri-implant subtrochanteric femur fracture.

INTERPRETATION

Cannulated screw fixation should be considered a valid option in intraarticular femoral Garden I-II fractures in elderly patients.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Screw fixation in stemless shoulder arthroplasty for the treatment of primary osteoarthritis leads to less osteolysis when compared to impaction fixation

Background

Stemless total shoulder arthroplasty is a well-established and reliable surgical treatment option for glenohumeral osteoarthritis resulting in loss of pain and improvement of shoulder function. Currently the two methods for the fixation of the humeral component are either screw fixation or impaction. The purpose of this study is the clinical and radiological comparison of two different stemless designs (screw fixation vs impaction) for total shoulder arthroplasties in patients suffering from primary glenohumeral osteoarthritis.

Methods

A retrospective cohort study including 39 patients with a mean age of 67 years and a minimum follow-up of 2 years was performed. Patients were separated into two groups based on the selected implant. In group A (n = 18) a screw fixation design and in group B (n = 21) an impaction type design was used. For clinical examination the Constant-Murley-Score (CS) and Subjective-Shoulder-Value (SSV) were evaluated. Radiological examination was performed on true-AP, axial and Y-view radiographs.

Results

In group A the CS increased from 27.1 to 65.2 points and SSV from 27.3 to 76.7% (p > 0.05). No osteolysis of the medial calcar or subsidence of the humeral implant were found in this group. In group B the CS increased from 29.0 to 72.6 points and SSV from 33.1 to 85% (p < 0.05). Osteolysis of the medial calcar was present in seven patients in this group. No signs for humeral loosening were found in both groups.

Conclusion

Impaction and screw fixation total shoulder arthroplasty for primary glenohumeral osteoarthritis using a stemless device provide reliable clinical results. The screw fixation seems to prevent osteolysis of the medial calcar.

Burkholderia pseudomallei peri-prosthetic infection following medial malleolar internal fixation: a case report

Background

Melioidosis-associated peri-prosthetic infection is extremely rare. To date, melioidosis associated septic arthritis of the ankle joint following a medial malleolar internal fixation has not been reported.

Case presentation

We describe a 49-year-old male with a history of long standing diabetes who presented with fever, constitutional symptoms and right ankle pain for 1 week. Ten years ago, he underwent a medial malleolar screw fixation following a traumatic closed fracture. His initial right ankle radiographs showed no evidence of osteomyelitis. He underwent a wound debridement and washout of the right ankle joint. The peripheral blood and pus from the ankle joint was culture positive for Burkholderia pseudomallei with very high antibody titres. His subsequent radiographs showed features of chronic osteomyelitis. He was treated with a prolonged course of antibiotics and repeated wound debridement. At follow up after 6 months, he had no clinical features of recurrent infection.

Conclusions

Melioidosis should be entertained in the differential diagnosis of peri-prosthetic infections in high risk patients.