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The purpose of this study was to describe the incidence of subsidence in patients with AO/OTA 41 (tibial plateau) fractures which were repaired with a novel fenestrated screw system to used to deliver CaPO4 bone substitute material to fill the subchondral void and support the articular reduction. Patients with unicondylar and bicondylar tibial plateau fractures were treated according to the usual technique of two surgeons. After fixation, the Zimmer Biomet N-Force Fixation System®, a fenestrated screw that allows for the injection of bone substitute was placed and used for injection of the proprietary calcium phosphate bone graft substitute into the subchondral void. For all included patients, demographic information, operative data, radiographs, and clinic notes were reviewed. Patients were considered to have articular subsidence if one or more of two observations were made when comparing post-operative to their most recent clinic radiographs: > 2 mm change in the distance between the screw and the lowest point of the tibial plateau, > 2 mm change in the distance between the screw and the most superior aspect of the plate. Data were analyzed to determine if there were any identifiable risk factors for complication, reoperation, or subsidence using logistic regression. Statistical significance was set at p

We report a case of treatment of a 60-year-old female patient D. with a metastatic fracture of the upper and middle third of the left humerus. We made a radical removal of the metastasis, which was complicated by pathological fracture of the left humerus. To replace the removed tumor defect we performed metal and polymer endoprosthetic replacement of the left humeral diaphysis using a locking screw system and bone cement (methyl methacrylate). For accelerated recovery and rehabilitation we applied adaptogenic immunomodulator «Vitavis» (Altai elixir) and neutral anolyte (NA). After the removal of the tumor, postoperative wound was treated with neutral anolyte (NA). Dressings also contained neutral anolyte (NA). These drugs were successfully combined with postoperative basic therapy. The patient was discharged from the hospital on the 4th day after surgery. The functional results of the left upper limb are satisfactory.

Purpose and Objectives This IRB‐approved study was to compare the residual inter‐fractional setup errors and intra‐fractional motion of patients treated with cranial stereotactic radiosurgery without a 6 degree of freedom (DoF) couch. We evaluated both frameless non‐invasive vacuum‐suction immobilization (Aktina PinPoint) and TALON rigid screw immobilization. Materials and Methods Twenty consecutive patients treated by Varian TrueBeam STX or Tomotherapy were selected for data collection. The dose and number of fractions received by each patient ranged from 18 Gy in 1 fraction (SRS) to 25 Gy in 5 fractions (SRT). Twelve patients were immobilized using PinPoint, a frameless suction system (Aktina Medical, New York) and eight patients were immobilized using the TALON rigid screw system. Customized head cushions were used for all patients. Six Atkina patients received pre‐ and post‐treatment cone‐beam CT (CBCT) to evaluate the intra‐fractional motion of the Aktina system. The intra‐fractional motion with the TALON rigid screw system has been reported to be negligible and was not repeated in this study. All patients received pre‐treatment CBCT or megavoltage CT (MVCT) to assess inter‐fractional setup accuracy. Shifts to the final treatment position were determined based on matching bony anatomy in the pre‐treatment setup CT and the planning CT. Setup CT and planning CT were registered retrospectively based on bony anatomy using image registration software to quantify rotational and translational errors. Results For the frameless Aktina system, mean and standard deviation of the intra‐fractional motion were −0.5 ± 0.7 mm (lateral), 0.1 ± 0.9 mm (vertical), −0.5 ± 0.6 mm (longitudinal), −0.04 ± 0.18°(pitch), −0.1 ± 0.23°(yaw), and −0.03 ± 0.17°(roll) indicating negligible intra‐fractional motion. Inter‐fractional rotation errors were −0.10 ± 0.25° (pitch), −0.08 ± 0.16° (yaw), and −0.20 ± 0.41° (roll) for TALON rigid screw immobilization versus 0.20 ± 0.69° (pitch), 0.34 ± 0.56° (yaw), 0.35 ± 0.82° (roll) for frameless vacuum‐suction immobilization showing that the rigid immobilization setup is more reproducible than the frameless immobilization. Without rotational correction by a 6 DoF couch, residual registration error exists and increases with distance from the image fusion center. In a 3D vector space, a tumor located 5 cm from the center of image fusion would require a 0.9 mm margin with the TALON system and a 2.1 mm margin with Aktina. Conclusions With image‐guided radiotherapy, translational setup errors can be corrected by image registration between pre‐treatment setup CT and planning CT. However, rotational errors cannot be accounted for without a 6 DoF couch. Our study showed that the frameless Aktina immobilization system provided negligible intra‐fractional motion. The inter‐fractional rotation setup error using Aktina was larger than rigid immobilization with the TALON system. To treat a single lesion far from the center of image registration or for multiple lesions in a single plan, additional margin may be needed to account for the uncorrectable rotational setup errors.

Trochanteric femur fractures are frequently fixed with a four-hole side plate sliding hip screw device, but in recent decades two-hole side plates have been used in an attempt to minimize operative time, surgical dissection, blood loss and post-operative pain. The aim of this review was to determine whether two-hole sliding hip screw constructs are an acceptable option for fixation of AO-OTA 31-A1 and A2 trochanteric femur fractures. An electronic MEDLINE® database search was performed using PubMed®, and articles were included in this review if they were reporting historical, biomechanical, clinical or outcome data on trochanteric fracture fixation using a two-hole sliding hip screw device. A two-hole dynamic hip screw with a minimally invasive muscle-splitting approach is recommended for fixation of AO-OTA 31-A1 simple trochanteric fractures; this implant is biomechanically safe, and allows the use of a minimally invasive muscle-splitting approach which potentially provides better clinical outcome, such as decreased surgical trauma, shorter operative time, less blood loss, decreased analgesics use, and shorter incision length. As the majority of reviewed publications relate to the dynamic hip screw, it is not clear whether the above recommendations can be extended to any other sliding hip screw device. An intramedullary device is recommended for all other extra-capsular proximal femoral fractures.Cite this article: EFORT Open Rev 2020;5:118-125. DOI: 10.1302/2058-5241.5.190020

This paper proposes a novel dual-drive hydrostatic lead screw system (DDHLS). The design enables a lower feed speed and a better transmission performance than the conventional hydrostatic lead screw (HLS). Considering the nut-misalignment, the lubricating mathematical model of the DDHLS is established based on the perturbation method and solved by the finite difference method. The influences of the nut-radial-displacement, the nut-tilt, and the dual-drivable design on the transmission performance of the DDHLS are researched. The results show the nut-misalignment can regularly reduce or increase the axial load capacity (ALC), the axial stiffness coefficient (ASC), and the axial damping coefficient (ADC). Significantly, the dual-drivable design can improve the axial load capacity and the axial stiffness coefficient while hardly affects the axial damping coefficient.

Background Pre-lifting of the sternum marked a major turning point in pectus excavatum repair. The author developed the crane technique in 2002 and successfully applied it to more than 2,000 cases using sternal wire stitching. However, blind sternal suturing limited the use of the wire-stitch crane. We propose a novel screw for sternal lifting as a new tool for the crane technique. Methods We developed a screw system strong enough to withstand the pressure needed for sternum lifting. The screw was designed to have a broader thread to hold the bony tissue securely. The screw's sustaining power was tested using the torsion, driving torque, and axial pull-out tests in a polyurethane block and ex-vivo porcine sternum. Results The screws were easily driven into the sternum, and the head of the screw was connectable to the table-mounted retractor. In the torsion test, the 2° offset torsional yield was 4.53 N·m (reference value, 1 N·m). In the polyurethane block driving torque test, the maximum torque was 0.98 N·m (reference value, 0.70 N·m). The axial pull-out test was 446 N (reference value, 100 N). The maximum pull-out resistance in the ex-vivo porcine sternum model was 1,516 N. Conclusion The screw crane was strong enough to sustain the chest wall weight to be lifted. Thus, the screws could effectively replace the sternal wire stitching in crane pre-lifting of the sternum. We expect that application of the screw-crane will be easy and that it will improve the safety and success rate of pectus repair surgery.

Case Patellar fractures after anterior cruciate ligament (ACL) reconstruction with a bone-patellar-tendon-bone (BPTB) autograft are a rare complication with a reported incidence of 0.2% to 2.3%. Treatment has previously been nonoperative splinting, lag screws, or a tension-band construct. We present the case of a 14-year-old adolescent girl who suffered a comminuted patella fracture 4 weeks after an ACL reconstruction using a BPTB autograft who subsequently underwent successful operative fixation through a novel technique with the use of a maxillofacial plate and screw system. Conclusion A maxillofacial plate and screw system is an effective and reliable treatment option for patellar fractures sustained after ACL reconstruction with a BPTB autograft.

Many medical implants require a fastening system to rigidly affix components. One such system for standard orthopedic implants is the PAX Polyaxial Locking System in which threaded screw heads are secured to the implant by cutting into holes of a tailored geometry. As most custom implants are fabricated by additive manufacturing (AM) techniques, investigating whether the PAX system can be printed along with the implant can facilitate its wider use and significantly decrease their cost. The geometry of PAX system was measured using an X-ray CT and recreated as a CAD for AM fabrication in stainless steel 316L and Ti6Al4V, two standard implant materials. The mechanical properties of the printed parts were altered using different heat treatments to receive various hardness of the material. This work characterizes the performance of a printed PAX system in terms of screw insertion and mechanical push-out force and compares it to the original system. It is found, that using AM 316L stainless steel may be utilized to produce a locking system in patient-specific additively manufactured implants.

Purpose: The aim of the present study is to understand the clinical outcomes of a novel hydroxyapatite-coated (HA-coated) titanium screw for surgical treatment of SI joint dysfunction. Background: The mainstay of therapy for disorders of the sacroiliac (SI) joint has been non-operative treatment including activity modification, non-steroidal anti-inflammatory drugs, and physical therapy. SI joint injections provide diagnostic information and occasional durable therapeutic benefit. When these modalities fail, sacroiliac joint fusion may be recommended. Objective: The objective of this study is to describe the clinical outcomes of a novel HA-coated titanium screw for surgical treatment of SI joint dysfunction. Methods: This study is a retrospective Institutional Review Board-exempt chart review of 45 consecutive patients who underwent minimally invasive SI joint fusion with a novel HA-coated screw system. Patients were diagnosed based on North American Spine Society guidelines and evidence-based criteria. Clinical assessments were collected, evaluated, and compared preoperatively and at 3, 6, 12, and 24 months postoperatively. Results: Mean patient age was 68.8 ± 9.4 years, and 61.7% of patients were female. Of the 44 patients, nine underwent bilateral SI joint fusion, while the remaining were unilateral. Screw size ranged from 10 × 35 mm to 10 × 50 mm. Mean preoperative visual analog scale (VAS) SI pain scores decreased significantly by a mean of 6.1 points at 12 months postoperatively (P

When vertebroplasty is used to treat Kummell disease with bone deficiency at the vertebral anterior border, bone cement displacement often occurs intraoperatively or postoperatively. We designed and used a new bone cement screw system to avoid this serious complication. The purpose of this study was to evaluate the safety and effectiveness of this novel operation method through more than 3 years of follow-up.From January 2014 to August 2016, 27 patients suffering from single-segment Kummell disease with bone deficiency at the vertebral anterior border were treated by vertebroplasty combined with a novel bone cement screw. Bone cement was released into the diseased vertebrae through the screw to fully fill the intravertebral vacuum cleft. Screw fixation of bone cement can avoid intraoperatively or postoperatively displacement. All patients received surgery involving a unilateral technique, and only one screw was implanted in each patient. The clinical efficacy was evaluated using Odom's criteria and statistical analysis of the vertebral body index (VBI), vertebral body angle (VBA), bisegmental Cobb angle (BCA), visual analogue scale (VAS), Oswestry disability index (ODI), and the results of the MOS 36-item short form health survey (SF-36).The operation was completed successfully in 27 cases. The average operation time was 49.63 ± 10.82 min, and the average volume of cement injected was 4.70 ± 0.87 mL. The patients' preoperative VBI, VBA, BCA, VAS and ODI scores were 43.11 ± 5.94, 21.04 ± 2.55, 45.00 ± 6.26, 7.59 ± 0.84, and 79.85 ± 7.58, respectively. The postoperative measurements were 78.70 ± 2.55, 12.70 ± 2.11, 26.11 ± 4.73, 3.22 ± 0.93 and 50.04 ± 9.28, respectively. At the last follow-up, the measurements were 78.04 ± 2.30, 13.15 ± 2.38, 27.07 ± 4.87, 2.04 ± 0.65, and 22.85 ± 5.06, respectively. There was a significant difference between the preoperative and postoperative data, as well as the preoperative and the last follow-up data (P 0.05). Comparing the results of SF-36 before operation and at the last follow-up revealed significant differences in physical function, role-physical, body pain, vitality, and social function (P 0.05). However, there were no significant differences in general health, emotional function and mental health. Finally, 26 patients (96.3 %) had good to excellent clinical outcomes according to Odom's criteria.This 3-year follow-up study shows that the novel bone cement screw system combined with vertebroplasty has a good short and medium-term therapeutic effect in patients with Kummell disease and bone deficiency at the vertebral anterior border, while its long-term efficacy is subject to further studies.

In this chapter, screw theory is introduced as a preliminary study to give readers an overview of screw theory and its application in compliant mechanism designs. The definition of a screw, as well as the key screw operations, are given in Sect. 2.2, such as the interchange operation of a screw, the screw coordinate transformation and the reciprocal product of two screws. Then the concept of the screw system is introduced in Sect. 2.3, which is an extension of the screw in a group form. Several typical screw systems are defined according to the reciprocal relationship between screws, notably the reciprocal screw system and repelling screw system. Further, the concepts of the screw and screw system are extended to describe the twist and wrench in Sect. 2.4, which are the two fundamental concepts in the further study of compliant mechanisms.

This paper presents an intuitive approach for mobility analysis of thin-panel origamis based on a coplanar 2-twist screw system, which consists of a pair of parallel/concurrent line vectors. In this study, we first proved that in any thin-panel origami, the allowable instantaneous mobility for any two facets connected to a third one can be described by a coplanar 2-twist screw system because this mobility is generated by two coplanar creases in the third facet. Second, the mobility of the basic origami units with a single facet loop was analyzed by using this coplanar 2-twist screw system. Third, the mobility analysis approach was extended to analyze the mobility of other planar/circular arraying origami patterns with multiple facet loops; typical origami patterns such as leaf-fold, Miura-ori were subjected to this analysis process. Furthermore, we proved that the proposed approach can be applied to the mobility analysis of complicated origamis; this approach proved to be considerably more intuitive than the traditional approach for mobility analysis.

Champy plates are becoming more and more accepted for the fixation of simple mandibular fractures. Champy plates have the following advantages over other metbods: the plates are small, flexible, easily adaptable and the monocortical screws allow a rapid surgical application. This case report and literature review examined the use of a locking bone plate/screw system for use in mandibular surgery. The use of a locking plate/screw system was found to be simple, and it offers advantages over conventional bone plates by not requiring the plate to be compressed to the bone to provide stability.

The Tape Locking Screw system (TLS) is a recognised technique used in anterior cruciate ligament reconstruction (ACLR). However, only a few previous studies have reported associated outcomes, all of which had been examined over a short-term period. The aim of this study was to assess the time-dependent changes in the objective and patient-reported outcome measures (PROM) in a group of patients with anterior cruciate ligament deficiency who have been operated on with this technique.Previously reported satisfactory short-term outcomes following TLS persist for several years after the operation.This study was a retrospective observational study including 26 patients, who were followed after unilateral ACLR with TLS. Anterior tibial translation (ATT) was measured in both knees using the KT-1000 arthrometer and two PROMs: International Knee Documentation Committee (IKDC) and Lysholm subjective form scores were examined preoperatively, 6 months postoperatively, and annually for 5 years thereafter in all patients.One patient suffered a rupture of the graft, and one patient had a screw loosening. Two patients were lost for follow-up, so 22 patients were the final study group. Median (25-75%) ATT side-to-side differences between the injured and uninjured sides were 4 (3,5-4)mm preoperatively, 0,75 (0-1)mm 1 year postoperatively, and 0,75 (0-1)mm 5 years after the operation (P0.001). Median (25-75%) IKDC scores were 44.25 (35.6-55.15), 92.55 (87.08-96.6), and 95.4 (90.8-97.7) points preoperatively and 1 year (P0.001) and 5 years postoperatively, respectively. Median (25-75%) Lysholm scores were 52 (38.75-64.5), 95.5 (94.75-99.25), and 97.5 (95-99) points preoperatively and 1 year (P0.001) and 5 years postoperatively, respectively.ACLR with TLS might already achieve favourable outcomes 1 year postoperatively, when measured objectively (ATT) and with PROMs. These outcomes persist 5 year postoperatively. LEVEL OF EVIDENCE IV: retrospective cohort study.

Currently, heated bed levelling method used in low cost FDM 3D printer is using spring and screw adjustment system that requires more effort and time. This is a part of ongoing research to design a novel leveling system for FDM 3D by introducing a new system to replace the screw system. Previous research has introduced a new concept design to quick and easy levelling of FDM 3D printer's heated bed using staggered pin design. This paper is to analyze the staggered pin system by simulating various dimensions and materials using Finite Element Analysis (FEA) simulation software. Best configuration was analyzed by comparing the VMS value obtained from the simulation. Using FEA, 18 design configurations have been simulated and analyzed. All configurations are strong and safe to apply and can be carried on for further research but Polyethylene (PE) material obtained lowest VMS value and suggested to be chosen. PE material also good for mass production because it can be manufactured by using plastic injection molding and can be sold in relatively lower price.

Objectives To evaluate the efficacy and safety of a novel fixation technique referred to as the dynamic anterior plate-screw system for quadrilateral plate (DAPSQ) for complex acetabular fractures with quadrilateral plate involvement through the single ilioinguinal approach. Methods A total of 32 patients with acetabular fractures, selected between January 2009 and March 2016, were managed by DAPSQ with "quadrilateral screws" through single ilioinguinal approach. The primary outcomes measure was the reduction quality evaluated according to the Matta radiological criteria, and the functional outcomes were evaluated by the modified Merle d'Aubigne score at the last follow-up. Secondary outcomes were postoperative complications and intraoperative conditions included, for instance, operation time and blood loss. Results Of these 32 consecutive patients, 19, 9, and 4 were classified as both columns, anterior column posterior hemi-transverse, and T-shaped fractures, respectively, and with an average of 47 months' follow-up. Anatomic reduction was obtained in 19 cases (59%), imperfect reduction in 9 cases (28%), and poor reduction in 4 cases (13%). The modified Merle d'Aubigne scores were excellent in 15 cases (47%), good in 13 cases (41%), fair in 2 cases (6%), and poor in 2 cases (6%). Three cases sustained temporary lateral femoral cutaneous nerve injuries. One patient had a superficial wound infection that resolved after debridement. Five patients had posttraumatic arthritis; one of them underwent total hip arthroplasty at 46 months. No cases had quadrilateral screws entering the hip joint. Conclusion The use of DAPSQ with quadrilateral screws is an effective and safe choice for complex acetabular fractures with quadrilateral plate involvement through the single ilioinguinal approach.

A mechanism composed of generalized links and kinematic pairs is defined as the generalized mechanism, which is capable of transforming motions and forces. It is an expansion of traditional rigid mechanisms and can better reflect the material characteristics. The constraint screw systems of limbs were constructed according to the screw description of generalized links and kinematic pairs. By using screw reciprocal operations, the kinematics screw can be obtained. In addition, the analysis method of kinematic characteristics was established. After that, the inverse-kinematics configuration synthesis method was proposed by inversing the mechanism kinematics analysis. Given the specified motion, the constraint screw system of generalized mechanism was obtained. The constraint screw system can be further decomposed and computed to get the limb kinematics screw systems. Accordingly, the kinematic limbs of the generalized mechanism were obtained. By permutating the kinematic limbs, the desirable configurations of generalized mechanism were obtained.

With the recent advancements in arthroscopic surgery, the use of suture anchor has increased in the surgical treatment of rotator cuff tears. In the present study, we developed a suture anchor system for ligament reconstruction that can be applied to patients with osteoporosis or with low bone density. The anchor screws are made of biocomposites containing poly-L-lactic-co-glycolic acid (PLGA) and beta-tricalcium phosphate (β-TCP) in a 70:30 ratio. The suture anchor system consisted of medial and lateral screw. The lateral screw was designed in a hemicylindrical structure to prevent bone damage. The performance of the developed anchor screw was found to be greater than 402.5 N in a pull-out test.