Locking Screws Research Articles

Inability to Remove Locking Screws from the Femoral Neck System due to Stripping of the Screwdriver within the Locking Screw Head.

The purposes of this study were to investigate the frequency of screwdriver stripping in the head of the locking screw that attaches to the side plate to the femur shaft among the patients who underwent implant removal after Femoral Neck System (FNS) for femoral neck fracture, to determine the risk factors for locking head screw stripping in FNS treatment of femoral neck fracture, and to suggest a surgical tip that removes FNS, which is difficult to remove due to screw stripping. Design: Retrospective cohort study. Eight Urban tertiary referral academic hospitals. Included were patients with OTA/AO 31-B1, 31-B2, and 31-B3 femoral neck fractures who underwent surgical fixation with FNS from Nov 2019 to Feb 2023. The frequency of locking head screw stripping of FNS during the implant removal was evaluated. Among the 47 patients (18 (38%) men and 29 (62%) women) who met the inclusion criteria with average age of 59.2 years (range, 28 to 94 years), 13 (27.7%) experienced screwdriver stripping in the head of the distal locking screw during FNS removal surgery. A higher BMI showed a borderline significant association with the stripping in the adjusted model (OR = 1.233; 95% CI: 0.988-1.539; p = 0.064). No other variables showed significant association with the stripped locking head screw (p>0.05). Stripping of the screwdriver within the head of the distal locking screw occurred in over one quarter of cases. While a higher BMI demonstrated a borderline significant association, none of the other variables examined showed a statistically significant relationship with the stripped locking head screw. Level III (retrospective cohort study).

Bicortical Compression and Construct Stability With Variable Pitch Locking Screws in Cadaveric Specimens.

A variable pitch locking screw is intended to provide interfragmentary compression combined with fixed angle stability of locking plate constructs. The objective of this study was to compare variable pitch locking screws (3.5-mm KreuLock Ti locking compression screws, Arthrex Inc., Naples, FL) with standard locking screws (from the same manufacturer) in bicortical fixation scenarios in cadaver bone by assessing (1) interfragmentary compression and plate-bone compression and (2) construct biomechanical stability. Nine matched pairs of fresh-frozen cadaveric specimens with an average age of 67.2 years (range, 37-83) were used. Interfragmentary compression and plate-bone compression associated with insertion of single bicortical screws were compared between the variable pitch and standard locking screws at increasing levels of torque. The specimens tested were distal tibiae having a simulated longitudinal fracture. Additionally, fibulae were osteotomized to create a stable longitudinal fracture pattern and were fixed with a 5-screw plate construct with either all variable pitch or all standard locking screws. One of the 5 screws was placed across the osteotomy without lagging. Fibulae were tested cyclically with axial with torsional loading to compare displacements, rotation, and loads at failure or tested in 4-point bending to compare construct stiffness and maximum force to failure. Interfragmentary and plate-bone compression forces in the distal tibia model varied across specimens but were significantly higher with variable pitch locking screws compared with standard locking screws [512 N (SD = 324 N) vs. 79 N (SD = 64 N), P = 0.002, and 242 N (SD = 119 N) vs. 104 N (SD = 123 N), P = 0.028, respectively]. In cyclic loading of fibula constructs, no significant differences were detected in construct axial displacement or angular displacement (P > 0.05). In 4-point bending, no differences were detected in maximum force or bending stiffness (P > 0.05). Variable pitch locking screws produced interfragmentary compression between cortices and plate-bone compression that was greater than that produced by standard locking screws. In a stable bicortical fibula fixation scenario under external loading, the stability of variable pitch locking screw constructs was similar to constructs with standard locking screws.

Survivorship and Clinical Outcomes of Reverse Total Shoulder Arthroplasty in Patients with Large Glenoid Defects Using the Stilting Technique and a Baseplate with Central Ingrowth Cage and Peripheral Locking Screws

Stilting is a novel technique used in reverse shoulder arthroplasty (RSA) in patients with significant glenoid bone loss. This technique utilizes peripheral locking screws placed behind an unseated portion of the baseplate, to transmit forces from the baseplate to the cortical surface of the glenoid, without the need for bone grafting. The stilted screw, once locked, provides a fixed angle point of support for an unseated aspect of a baseplate. The primary advantages of this technique are reduced cost compared to a custom implant and reduced operative time compared to bone grafting. We conducted a retrospective, non-randomized, comparative cohort study of 41 patients underwent primary Reverse Shoulder Arthroplasty (RSA) using the Stilting Technique with the Exactech Equinoxe Reverse System (Gainesville, FL, USA) at a single, academic center from the years 2004-2021. Exclusion criteria included age under 18 or over 100, and oncologic or acute fracture RSA indications. Operative data was documented, including implant records, percent baseplate seating, and operative duration. Survivorship was compared among primary stilted-RSA (n=41), bone graft-RSA (n=42), and non-stilted/non-bone grafted RSA (n=1,032) within our institutional shoulder arthroplasty database. A radiographic examination of baseplate failure was also conducted across the study groups. Postoperative functional outcomes were compared in a matched analysis involving patients with a minimum 2-year follow-up between stilted patients and a non-stilted/non-bone grafted control group for primary RSA. All Stilted-RSA cases utilized metal augments and demonstrated a mean baseplate seating of 61% (range 45-75%). For stilted RSAs, survivorship was 100% and 92.6% at 2- and 5-years, compared to 98.3% and 94.6% for non-stilted/non-bone grafted and 96.3% and 79.5% for bone-grafted RSAs (p=0.042). At 5-years, the baseplate-related failure rates were greater in the stilted (7.4%) and the bone-grafted (9.3%) cohorts compared with the non-stilted/non-bone grafted cohort (1.1%, p<0.001). The mean time to baseplate failure was 30 months for stilted RSA. Functional outcomes for primary RSA were statistically similar between stilted and non-stilted patients, including range of motion, Constant, ASES, SST, UCLA, and SPADI scores. The stilted-RSA cohort exhibited noninferior revision and baseplate failure rates to that of bone-grafted RSA. This suggests that stilting may be a viable technique for patients undergoing primary RSA with significant glenoid deformity.

Effect of Different Screw Materials on ACL Reconstruction With the Tape Locking Screw Technique: A Retrospective Study From the FAST Cohort.

Screws for graft fixation are available in 3 different materials for anterior cruciate ligament reconstruction (ACLR) with the Tape Locking Screw (TLS) technique: titanium, poly-l-lactic acid bioabsorbable, and polyetheretherketone (PEEK). To compare the effect of the 3 different fixation materials on graft and implant survival after ACLR with the TLS technique. Cohort study; Level of evidence, 3. Included were 521 patients from the French Prospective ACL Study (FAST) cohort who underwent primary surgical ACLR with the TLS technique. Patients were divided into 3 groups depending on the type of screw material used: titanium (TLS-T group), poly-l-lactic acid bioabsorbable (TLS-B group), or PEEK (TLS-P group). The primary endpoint was a retear within 2 years after ACLR. The secondary endpoints were complication rate, return to sports rate, and functional scores. Objective and subjective functional scores-including the International Knee Documentation Committee, the Knee injury and Osteoarthritis Outcome Score (KOOS), and the Lysholm score-were evaluated preoperatively and at the 2-year follow-up. Pain was assessed with the KOOS-Pain subscore recorded pre- and postoperatively every 6 months up to 2 years. Patient satisfaction was recorded at the 2-year follow-up. No significant differences between the study groups were found in retear rates (4.4%, 4.5%, and 4.3% in the TLS-T, TLS-P, and TLS-B groups 2 years after surgery) or subjective and objective outcomes. The TLS-T group had the lowest rate of intraoperative implant-related complications (0.9%) compared with the TLS-P (4.3%) and TLS-B (7.7%) groups. Young age was a significant risk factor for retear in the TLS-T (P = .03) and TLS-B (P = .0001) groups, while a high level of sports was found to be a significant risk factor in the TLS-P (P = .04) group. All functional scores improved significantly at the 2-year follow-up (P < .0001), with no significant group difference. The KOOS-Pain subscore improved continuously with no significant group difference. The rate of return to preinjury sports was between 43.4% and 58.6%. The rate of highly satisfied patients at the final follow-up was between 86.2% and 91.8%. There was no difference in retear rate or objective and subjective functional scores between implant materials for TLS ACLR in this study.

Critical loss of primary implant stability in osteosynthesis locking screws under cyclic overloading

Primary implant stability, which refers to the stability of the implant during the initial healing period is a crucial factor in determining the long-term success of the implant and lays the foundation for secondary implant stability achieved through osseointegration. Factors affecting primary stability include implant design, surgical technique, and patient-specific factors like bone quality and morphology. In vivo, the cyclic nature of anatomical loading puts osteosynthesis locking screws under dynamic loads, which can lead to the formation of micro cracks and defects that slowly degrade the mechanical connection between the bone and screw, thus compromising the initial stability and secondary stability of the implant. Monotonic quasi-static loading used for testing the holding capacity of implanted screws is not well suited to capture this behavior since it cannot capture the progressive deterioration of peri‑implant bone at small displacements. In order to address this issue, this study aims to determine a critical point of loss of primary implant stability in osteosynthesis locking screws under cyclic overloading by investigating the evolution of damage, dissipated energy, and permanent deformation. A custom-made test setup was used to test implanted 2.5 mm locking screws under cyclic overloading test. For each loading cycle, maximum forces and displacement were recorded as well as initial and final cycle displacements and used to calculate damage and energy dissipation evolution. The results of this study demonstrate that for axial, shear, and mixed loading significant damage and energy dissipation can be observed at approximately 20 % of the failure force. Additionally, at this load level, permanent deformations on the screw-bone interface were found to be in the range of 50 to 150 mm which promotes osseointegration and secondary implant stability. This research can assist surgeons in making informed preoperative decisions by providing a better understanding of the critical point of loss of primary implant stability, thus improving the long-term success of the implant and overall patient satisfaction.

Comparison of the retear rate 2 years after ACL reconstruction with the Tape Locking Screw short graft system and the STG technique: A case control study with propensity score matching

PurposeTheoretically, short semitendinosus grafts result in less pain and morbidity while providing greater knee flexion strength and sparing the gracilis tendon. They often require the use of blind bone tunnels as well as fixation at both ends of the graft with suspensory cortical buttons. The “Tape Locking Screw” (TLS) system is another option. There are few studies comparing ACL reconstruction with a short graft using the 4-strand semitendinosus graft (ST4-TLS) technique with that of the semitendinosus-gracilis (STG) procedure. This study was designed: (1) to compare the retear rate following these two technics after 2years of follow-up, (2) to compare the clinical scores, complications and return to sport times between the two procedures Q1, Q2. HypothesisOur hypothesis was that there would be no differences in retear rates between the two techniques. MethodsThis single center case control study included 290 patients who underwent STG reconstruction that were paired by propensity score matching to 299 patients who underwent ST4-TLS reconstruction. The main evaluation criterion was the retear rate 2years after surgery. Secondary criteria were the two-year postoperative complication rate, the time to return to sport, to pivot sports and to running, as well as the complication rates and clinical scores 6months, 1year and 2years after surgery. ResultsAt the final follow-up, the overall retear rate in our series of ACL ligament reconstruction was 6.0% (36/596). There was no difference in retear rates between the groups 2years after ligament reconstruction [ST4-TLS: 6.7% (20/299) vs. STG: 5.4% (16/297); p=0.47]. The postoperative KOOS symptom score and the Tegner score were found to be better in the STG group at 1year (81 vs. 78, p=0.008) and 2years (5.64 vs. 5.10, p=0.016), respectively, representing the minimally clinically important difference (MCID) for the latter. No difference was found in the other clinical scores 6months, 1year or 2years after surgery. There was no significant difference in the return to sport [TLS: 93.0% (164/299) vs. STG: 93.0% (158/297) p=0.99] or the complication rate [TLS: 8.7% (26/299) vs. STG: 7.4% (22/297) p=0.89] between the groups. DiscussionThe ST4-TLS ACL ligament reconstruction technique was found to be as reliable as the standard STG procedure 2years after surgery for the retear rate and the return to sport, although the results of certain postoperative clinical scores seem to be lower. Level of evidenceIII; case control study.

Comparing the Biomechanical Stability of Cerclage Cable with Plate Insert Versus Locking Screw in Periprosthetic Humeral Fracture.

In the setting of periprosthetic humeral fractures, the humeral stem of the implant represents a substantial challenge to the optimal method of proximal fixation. This study aimed to compare the initial biomechanical stability provided by cerclage cables with a locking plate insert versus bicortical locking screws (i.e., the gold standard for fixation) in fresh cadaveric humeri. After calculating the sample size, we utilized 10 sets of cadaveric specimens and created a 5-mm osteotomy gap 120 mm distal to the tip of the greater tuberosity, simulating a Wright and Cofield type-B periprosthetic humeral fracture on each specimen. Using 3 locking screws for distal fragment fixation, identical in all specimens, the specimens were assigned to Group A (3 cerclage cables with a plate insert) or Group B (3 locking bicortical screws) for proximal fragment fixation. Biomechanical tests included stiffness in varus and valgus bending, torsion, and axial compression, and a single load to failure. No significant differences were observed in the biomechanical metrics between the 2 groups. Our study revealed that fixation with use of cerclage cables with a plate insert demonstrated biomechanical stability comparable with that of bicortical locking screw fixation when addressing the proximal fragment in Wright and Cofield type-B periprosthetic humeral fractures. For proximal fragment fixation of periprosthetic humeral fractures, cerclage cables with a plate insert can be utilized as an effective fixation method that offers initial fixation strength that is comparable to the use of 3 locking bicortical screws.

Anterior cruciate ligament reconstruction with a single hamstring tendon graft and tape locking screw (TLS) fixation leads to good clinical outcome in two years of follow-up

BackgroundThere are many fixation methods for hamstring tendon autograft available for anterior cruciate ligament (ACL) reconstruction. The intention of this study was to report clinical follow-up data of the Tape Locking Screw (TLS) reconstruction technique. HypothesisDoes TLS method give good long term results in patient satisfaction and in clinical knee tests. Patients and methodsWe selected 119 prospectively collected patients with a two-year follow-up who had an ACL reconstruction using TLS technique. A total of 114 cases were available for follow-up two years postoperatively. The evaluation methods were instrumented laxity measurements, clinical examination and knee scores. ResultsThe Lysholm and IKDC scores improved from preoperative 76 and 50 to 95 and 90, respectively. Tegner activity level before surgery was 3 and improved to 6 at 2 years postoperatively. DiscussionACL reconstruction with TLS technique showed good objective outcome at the 2-year follow-up. We confirmed improvement in all evaluation method variables. Level of evidenceCase series; level of evidence, 4. Trial registrationISRCTN registry, study ID ISRCTN34011837. Registered retrospectively April 29, 2020.

Research of immune clone algorithm applying in the LED lamp automatic lock screw workstation

A new automatic lock screw machine for LED lamp has been researched in the paper, which is based on the immune clone algorithm. Firstly, the robot automatic lock screw system has been setup. Vision sensor captured LED lampshade images in real-time. Median filtering operation has been performed to the captured images. On this basis, a new image segmentation method based on the immune clone algorithm has been researched. The antibody and antigen of LED lampshade image have been defined. The immune affinity function has been setup at the same time. Several artificial immune operators have been designed, which can be used to obtain the optimum image segmentation threshold value in real time. The final results showed that the optimum image threshold value can been obtained after less than ten times iterative computation. Compared with the traditional Ostu method, the new method can reduce the disturbance information around the threaded hole, which made basis for threaded hole recognition and location.

Weight-bearing as tolerated following distal femur fracture surgically treated with Far Cortical Locking screws

Objectives To review outcomes of a consecutive, non-selected series of distal femur fractures treated with a dynamic plate construct and allowed unrestricted weight bearing immediately after surgery. Design Retrospective consecutive case series. Setting Level 2 trauma center Patients/Participants Thirty-one consecutive distal femur fractures in 29 patients with 33A and 33C fractures stabilized with a distal femur locking plate and Far Cortical Locking diaphyseal screws. Intervention All patients were allowed immediate unrestricted weight bearing with assistive devices post-surgery. Main Outcome Measure Loss of reduction from immediate post-operative alignment, implant failure, nonunion, and medical complications. Results No loss of alignment greater than three degrees in the lateral distal femoral angle was noted at healing. Two implant failures occurred, one in the first five weeks and another in an established nonunion. Mortality at one year was 6.5%. Readmission for medical complications was noted in 6.5% of patients. Conclusions Immediate, unrestricted weight bearing after fixation of 33A and 33C distal femur fractures with a dynamic plate construct may be safe, with a low risk of implant failure or loss of coronal plane alignment. Relative to historical reports, morbidity and mortality in our cohort were improved with early weight-bearing. Level of Evidence Therapeutic Level IV, case series

Fracture treatment in atrophic mandible.

Fractures of the atrophic mandible have been historically treated in various ways, from intermaxillary fixation to internal fixation, some cases require bone grafts. Besides, the Luhr classification serves as a guide to select the type of treatment. To show the treatment of fractures in atrophic mandible with plates and screws, and the potential indications of bone graft in this type of fractures. We presented a serie of 17 patients with atrophic mandible treated with plates and screws, some of them no blocked system and other with locked screws. For patients in luhr classes II and III cancellous bone grafts were used, looking for best osteogenic response, harvesting for the proximal third of the tibia. Postoperative progress was generally uneventful. Oral intake with purees was resumed 24 hours after surgery, as well as ambulation. Fracture healing at 6 months was seen in 17 patients. One patient died before the 6-month time point as the result of a stroke. Delayed union was diagnosed 3 months after surgery in another patient, who refused secondary treatment. Treatment of fractures in atrophic mandibles with plates and screws is a reliable procedure. Luhr classification provide useful guidance regarding the use of bone grafts for best osteogenic response in the fracture. This treatment allows a quick restart of the feeding by mouth and movilization of the patients.

A Simple Technique to Facilitate Distal Locking Screws Placement in Intramedullary Nailing

A Simple Technique to Facilitate Distal Locking Screws Placement in Intramedullary Nailing

Efficacy of Far Cortical Locking Screws in Treating Distal Tibia Fractures in Comparison With That of Standard Locking Screws

There are no clinical studies about treatment of distal tibia fractures using far cortical locking (FCL) screws, even though it has been shown to be superior to standard locking screws in biomechanical studies. We compared the efficacy of FCL screws to that of traditional locking screws. Twenty-five distal tibia fractures were treated with minimally invasive plate osteosynthesis using traditional locking screws, whereas 20 were treated using FCL screws. We retrospectively compared time taken for callus formation and radiographic bone union between 2 groups. The effect of age, sex, diabetes, and smoking history on bone healing was analyzed. Complications were also noted. As a result, there was no significant difference in age (p = .292), sex (p=1.0), diabetes (p=1.0), or smoking history (p = .704) between 2 groups. Time to callus formation was 77.5 days in the FCL group, and 96 days in the traditional group (p = .023). Average time to bone union was 134.8 days, and 163.1 days in the FCL group and the traditional group, respectively (p = .017). There was one case of screw loosening in the FCL group, and one case of screw breakage in the traditional group. This study suggests that FCL screws promote quicker healing of distal tibia fractures than traditional locking screws.

Comparison of Dynamic Versus Static Lag Screw Modes for Short Cephalomedullary Nails in the Treatment of Unstable Intertrochanteric Fractures: A Randomized Controlled Trial

Purpose: To compare the static locked and sliding proximal lag screw modes of short cephalomedullary nail in the treatment of unstable intertrochanteric fractures. Methods: Ninety-four patients (age&gt;60 years) with low energy unstable intertrochanteric fractures were randomized for treatment into two groups. They were treated with static and sliding proximal lag screw modes of short cephalomedullary nail. The pre-operative variables, operative time, fluoroscopy time, blood loss, tip apex distance, and reduction quality were recorded for each patient. Post-operative follow-ups were undertaken every other week until bone union or implant failure occurred. Plain anteroposterior and lateral radiographs (both hip) were obtained at all visits. Ipsilateral leg length discrepancy (LLD), radiographic union score for hip complications, and fixation failure were recorded. Results: The mean follow-up time was 16.7 months (range 12–24). The mean bone union times of static locked (n=35) and sliding proximal (n=34) screw mode groups were 12.4 weeks and more than 11.2 weeks, respectively; the difference was not significant (p=0.213). The ipsilateral LLD of the sliding proximal (mean 4 mm) and static locked (mean 2 mm) screw mode groups showed a statistically significant difference (p&lt;0.001). Post-operative complications (lag screw perforated to hip joint, lag screw cutout from the femoral head, and excessive inferolateral lag screw sliding) developed in 8.82% patients in sliding proximal group, whereas, no complications were reported in the static locked group. Conclusions: Treatment of unstable intertrochanteric fracture using static locked proximal lag screw mode of cephalomedullary nail showed some advantages over sliding proximal lag screw in terms of less complication and ipsilateral LLD; however, the bone union times were not different. Therefore, a static locked proximal screw mode is preferable over sliding proximal screw mode in treating unstable intertrochanteric fractures.

A comparison of the inflammatory host response to particulate debris adjacent to unlocked and locked screws of a growth guidance system for early onset scoliosis.

The SHILLA™ Growth Guidance system is a stainless-steel rod and screw system used for Early Onset Scoliosis which incorporates a unique flanged set screw designed to capture the rod, while allowing it to slide as the patient grows. Concomitant with this design is the potential for generation of wear debris and for an inflammatory host response. We hypothesized that the magnitude of the host response adjacent to the unlocked screws and rods would be greater than the host response to the locked rod/screws. Seven tissue samples adjacent to locked (3) and unlocked screws (4) from three SHILLA patients (mean implantation time of 19 post-operative months) with infantile idiopathic scoliosis were obtained as part of an explant analysis protocol during a PMDA-approved clinical trial in Japan. Gross appearance, high-resolution radiographs, and histology were assessed. ISO Standard 10993 Part 6 was used to assess the host response. All three locked screw had no metallosis. In contrast, metallosis for unlocked screw tissue samples were rated as "ubiquitous" (2/4), "focal" (1/4), or "absent" (1/4). Microscopic metallic debris was found intracellularly and within interstices of fibrous connective tissues more frequently adjacent to unlocked screws compared to locked screws. Cell type and population scoring consistently showed a modestly larger inflammatory response (macrophages) in the unlocked tissue samples. The peri-prosthetic tissue response to the unlocked rods/screws had a higher reactivity grade (slight reaction, Δ = 4.0) per ISO 10993 Part 6 compared to the locked screws in three patients with the SHILLA™ Growth Guidance scoliosis system.

Evaluating the Stability of Locking Screw on Locking Compression Plate According to Various Screw Insertion Angles

Evaluating the Stability of Locking Screw on Locking Compression Plate According to Various Screw Insertion Angles

Influence of the Near-Cortical Over-Drilling Technique on the Mechanical Behaviour of Locking Plate Constructs Applied in Maned Wolf's Femur.

The aim of this study was to evaluate the influence of near-cortical over-drilling holes on the mechanical behaviour of locking plate constructs applied in maned wolf's femur by using mechanical testing and finite element method (FEM). Seven pairs of adult maned wolves (Chrysocyon brachyurus) femur bones were randomly distributed into four groups. In all groups, a 3.5 mm locking compression plate, designed with 12 combi-holes and one locked, was applied to the lateral surface of the femur. G1 (n = 4) received bicortical locking screws placed in holes 1, 3, 5, 8, 10 and 12. In G2 (n = 5), the plate was applied as used in G1, but the application of the locked screws involved the near-cortical over-drilling technique. In G3 (n = 4), the plate was applied as used in G2, but the size of the near-cortical over-drilling was larger. The combi-holes 6 and 7 were maintained over a 10 mm fracture gap without screws. All constructs were tested for failure in the axial load. The axial load was applied eccentrically to the femoral head. Statistical differences were observed in the maximum load with G3 > G1 and G3 > G2, and in the deflection with G2 > G1 and G2 > G3. The FEM showed the lowest total displacement of the bone-plate constructs as well as of the plate in G1 compared with G2 and G3. The near-cortical over-drilling technique used in unstable fractures induced in the maned wolf's femur showed by static axial compression test that maximum load and deflection are dependent on drill hole size induced in the near-cortex. Based on FEM, the lowest total displacement of the bone-plate constructs was observed in Group 1.

Outcomes of Mini-Invasive Arthroscopic Arthrolysis Combined with Locking Screw and/or Intramedullary Nail Extraction after Osteosynthesis of the Proximal Humerus Fracture.

Data on the effectiveness of arthroscopic arthrolysis and extraction of osteosynthetic material after osteosynthesis of the proximal humerus in patients with persisting problems are rare and insufficient. In this study, we performed arthroscopic arthrolysis and extraction of fixation screws, and, where protruding, extraction of the nail in 34 patients with problems persisting 12 months after osteosynthesis of the proximal humerus using an intramedullary nail. The effectiveness of the treatment was assessed using the Constant–Murley shoulder score and forward flexion difference between the treated arm and the contralateral one. A median increase of 16 points in CMS score and 30 degrees reduction in the arm forward flexion difference was recorded 12 months after the arthroscopy. The improvement was significantly higher in the patient group with intramedullary nail extraction (however, this group had worse pre-operative values and the screw was only extracted where likely to cause problems). The median time to heal was 11 weeks; no serious peri- or post-procedural complications occurred. Mini-invasive arthroscopic arthrolysis combined with extraction of osteosynthetic material proved to be a safe and effective method for treatment of patients after osteosynthesis of the proximal humerus using an intramedullary nail with persisting pain and/or mobility limitation.

Sliding wire detection system of electric lock screw tool based on motor characteristics

This paper presents a sliding wire detection system of electric screw locking tool based on the characteristics of motor. The system can judge whether the screw has sliding wire through the current change of motor during normal operation, and realize the real-time detection and alarm of sliding wire. The system has the advantages of high sensitivity, low cost and high accuracy. It can be widely used in automatic assembly and other fields.

Anterior cruciate ligament reconstruction with short hamstring grafts: the choice of femoral fixation device matters in controlling overall lengthening.

The purpose was to conduct an independent biomechanical study comparing the main types of femoral fixation adapted to short hamstring grafts in anterior cruciate ligament (ACL) reconstruction surgery and to validate their performance. The ACLip® Femoral, ToggleLoc™ Ziploop (TLZ), and Tape Locking Screw (TLS®) implants were tested in tension in the following three different configurations: implant alone, implant fixed on the femur without graft, and implant fixed on the femur with graft. Grafts alone were also tested. The femurs and the 4-strand semi-tendinosus grafts were derived from porcine and human models, respectively. Each set-up was subjected to the same protocol of creep (50N for 30s), cycling (1000 cycles between 50 and 250N, 1Hz), and load to failure (50mm/min). A total of 93 tests were performed (30 ACLip®, 30 TLZ, 20 TLS®, and 13 ST4 alone). For the implants tested with femur and graft, the mean ± standard deviation (SD) overall elongation at 250N after cycling was 5.2 ± 0.2mm, 8.4 ± 2.1mm, and 5.3 ± 0.8mm, the mean ± SD ultimate load to failure was 736 ± 116N, 830 ± 204N, and 640 ± 242N, and the mean ± SD stiffness at the 1000th cycle was 185 ± 15N/mm, 172 ± 19N/mm, and 178 ± 21N/mm for ACLip®, ToggleLoc™, and TLS® devices, respectively. There was no significant difference between the implants except for post-cycling elongation between TLZ and the other two implants (p < 0.05). The choice of femoral fixation device plays a decisive role in controlling the overall lengthening of an ACL reconstruction using a short hamstring graft. All implants validated the specifications in terms of ultimate load to failure, the TLS® system had, however, a low performance limit. ToggleLoc™ with adjustable loop should no longer be used on the femur side; instead the other types of fixation should be used to improve the overall elongation control.