Static Interlocking Research Articles

Research progress on distal interlocking screws of cephalomedullary nails in intertrochanteric fractures

To summarize the new research progress in distal interlocking screws of cephalomedullary nails for the treatment of intertrochanteric fractures. Relevant domestic and foreign literature was extensively reviewed to summarize the static/dynamic types of distal interlocking screw holes, biomechanical studies, clinical studies and application principles, effects on toggling in the cavity, and related complications of distal interlocking screws. The mode of the distal interlocking screw holes can be divided into static and dynamic. Distal interlocking screws play the role of anti-rotation, maintaining femur length, resisting compression stress, increasing torque stiffness, resisting varus stress, etc. The number of the screws directly affects the toggling of the main nail in the cavity. At present, regardless of whether long or short nails are used, distal interlocking screws are routinely inserted in clinical practice. However, using distal interlocking screws can significantly increase the duration of anesthesia and operation, increase fluoroscopy exposure time, surgical blood loss, and incision length. There is a trend of trying not to use distal interlocking screws in recent years. No significant difference is found in some studies between the effectiveness of dynamic and static interlocking for AO/Orthopaedic Trauma Association (AO/OTA) 31-A1/2 fractures. At present, the selection of the number and mode of distal interlocking screws is still controversial. When inserting distal interlocking screws, orthopedists should endeavor to minimize the occurrence of complications concerning miss shot, vascular injuries, local stress stimulation, and peri-implant fractures. Distal interlocking screws are mainly used to prevent rotation. For stable fractures with intact lateral walls, long cephalomedullary nails can be used without distal interlocking screws. For any type of intertrochanteric fractures, distal interlocking screws are required when using short cephalomedullary nails for fixation. Different interlocking modes, the number of interlocking screws, and the application prospects of absorbable interlocking screws may be future research directions.

A model experiment on the modern microscopic theory of sliding friction

According to modern understanding, sliding friction is caused by the displacement of the irregularities and individual atoms in the interaction zone of the sliding interfaces, leading to microscopic oscillations around the equilibrium position (the stick/slip model of Tomlinson). This is in contrast to the traditional account of sliding friction (static interlocking asperities), which in fact is insufficient (see online Appendix for more information about the theoretical background and its development).

Pilot study of micromotion nailing for mechanical stimulation of tibial fracture healing.

AimsThe study objective was to prospectively assess clinical outcomes for a pilot cohort of tibial shaft fractures treated with a new tibial nailing system that produces controlled axial interfragmentary micromotion. The hypothesis was that axial micromotion enhances fracture healing compared to static interlocking.MethodsPatients were treated in a single level I trauma centre over a 2.5-year period. Group allocation was not randomized; both the micromotion nail and standard-of-care static locking nails (control group) were commercially available and selected at the discretion of the treating surgeons. Injury risk levels were quantified using the Nonunion Risk Determination (NURD) score. Radiological healing was assessed until 24 weeks or clinical union. Low-dose CT scans were acquired at 12 weeks and virtual mechanical testing was performed to objectively assess structural bone healing.ResultsA total of 37 micromotion patients and 46 control patients were evaluated. There were no significant differences between groups in terms of age, sex, the proportion of open fractures, or NURD score. There were no nonunions (0%) in the micromotion group versus five (11%) in the control group. The proportion of fractures united was significantly higher in the micromotion group compared to control at 12 weeks (54% vs 30% united; p = 0.043), 18 weeks (81% vs 59%; p = 0.034), and 24 weeks (97% vs 74%; p = 0.005). Structural bone healing scores as assessed by CT scans tended to be higher with micromotion compared to control and this difference reached significance in patients who had biological comorbidities such as smoking.ConclusionIn this pilot study, micromotion fixation was associated with improved healing compared to standard tibial nailing. Further prospective clinical studies will be needed to assess the strength and generalizability of any potential benefits of micromotion fixation.Cite this article: Bone Jt Open 2021;2(10):825–833.

A comparative study of ultrasound and x-ray in detection, of fracture callus in tibial shaft fractures, treated by unreamed interlocking nailing

<p class="abstract"><strong>Background:</strong> Trauma is a major health problem in young adults and adolescents. It is a major cause of disability with fracture being a leading contributor to hospital cost and lost productivity in the workplace. Comparative study of ultrasonography and radiography in the early detection of fracture callus in tibial shaft fracture treated by unreamed static interlocking nailing.</p><p class="abstract"><strong>Methods:</strong> All skeletally mature patients admitted to Krishna Kumar Orthopedic Hospital, Nagercoil were included in our study from 2007 to 2008. 21 patients totally, who had sustained an acute fracture of the tibial shaft and who were treated by statically locked unreamed interlocking nailing were candidates for the study.<strong></strong></p><p class="abstract"><strong>Results:</strong> The mean±standard deviation for ultrasound and X-ray method of detection fracture callus in fractures shaft of tibia treated with static interlocking nailing are 4.82±1.01 and 7.05±1.02 respectively which is statistically highly significant. This analysis reveals that ultrasound detects fracture callus much earlier than X-ray.</p><p class="abstract"><strong>Conclusions:</strong> Ultrasound was able to detect fracture callus in tibial shaft fracture treated by a static unreamed interlocking nail. There was a statistically high significance difference of 2.23 weeks between the two techniques Ultrasound was done using a 7.5 MHz linear transducer probe. Ultrasound could detect fracture callus at a mean period of 4.82 weeks. Whereas X-rays could d detect fracture callus only at a mean period of 7.05 weeks.</p>

Surgical Repair of Radial-Ulnar Fracture by Static Intramedullary Interlocking Nailing in a Crossbred Heifer

Study included surgical management of radius and ulna fracture in a 2-year-old, 220 kg crossbred heifer presented with a 2-day-old history of injury resulting in severe, non-weight bearing lameness of the left forelimb. The condition was diagnosed clinically and confirmed radiographically as a middle third oblique comminuted fracture of the left radius and ulna. Static intramedullary interlocking nailing was performed for fracture fixation. An interlocking nail of 12-mm diameter and 26-cm length was introduced in a retrograde manner from the distal aspect of the radius. The animal was able to bear weight on the affected limb within 7 days post surgery. Good callus formation and complete weight bearing were observed by 35th day. Bending of the screws and osteophytic reaction were the major postoperative complications observed radiographically. From this case study, it was established that static intramedullary interlocking nailing can be used as an alternative technique for fracture repair of the radius and ulna in cattle where stable fracture fixation by bone plating is questionable.

Tratamento de fraturas patológicas tumorais diafisárias do úmero com haste intramedular rígida bloqueada estática – Experiência de 22 anos

ObjectiveRetrospective observational study in patients submitted to fixation with intramedullary nail after established or impeding pathological humerus‐shaft tumoral fracture in the context of disseminated tumoral disease alongside 22 years experience in the same institution. MethodsSample with 82 patients and 86 humeral fixations with un‐reamed rigid interlocking static anterograde or retrograde intramedullary nail. ResultsThe most prevalent primary tumors were breast carcinoma (30.49%), multiple myeloma (24.39%), lung adenocarcinoma (8.54%), and renal cell carcinoma (6.10%). The average nailing operation time was 90.16 ± 42.98minutes (40‐135). All patients referred arm pain improvement and there was a MSTS mean score rise from 26% in the preoperative to 72.6% in the evaluation performed in the still living patients three months after the surgery. The survival rate showed an overall survival of 69.50% at three months after surgery, 56.10% at six months, 26.70% at one year, and 11.90% at two years. None of the deaths were related to the surgery or its complications. There were only four complications related to the operation, one intraoperative and three late, corresponding to a 4.65% complications risk. ConclusionClosed un‐reamed static interlocking intramedullary nailing (anterograde or retrograde) of the humerus is a fast, safe, effective, and low morbidity procedure in the treatment of pathological fractures of humerus shaft, guaranteeing a stable arm fixation and consequently improving function and life quality of these patients during their short life expectation.

A prospective multi-center study of intramedullary nailing vs casting of stable tibial shaft fractures

BackgroundThe purpose of this study was to determine optimal treatment of stable tibial shaft fractures using intramedullary nailing (IMN) or casting.Materials and methodsWe performed a multi-center prospective study cohort. Patients with stable tibia shaft fractures meeting Sarmiento’s criteria (isolated closed fractures with less than 12 mm of shortening and 10° of angulation) were enrolled prospectively and treated with either a reamed IMN with static interlocking screws or closed reduction followed by long-leg casting. Both groups were weight bearing following surgery. Radiographs were taken until union, and range of motion of knee and ankle joints was assessed. Malalignment (>5°) and malunion (>10°) were determined. Functional outcome measures using short musculoskeletal assessment scores (SMFA) and a knee pain score were scheduled at 6 weeks, 3 months and 6 months.ResultsAt 3 months, differences between the casting and IMN groups were noted in return to work (6/15 vs 3/17, P < 0.05); ankle dorsiflexion (7° vs 12°, P < 0.05); plantar flexion (28° vs 39°, P < 0.05); and SMFA domains of Dysfunction Index, Bother Index, daily activities, emotional status, and arm/hand function (P < 0.05). The SMFA mobility function demonstrated a significant trend (P = 0.065). At 6 months, malalignment was present in 3/15 in the casting group and in 1/17 in the IMN group (P = 0.02). Malunion was present in 1/15 in the cast group. One fracture in the casting group went on to nonunion and required late IMN placement at 7 months and eventually healed. There were no differences in ankle motion, SMFA scores, or return to work. There was no difference in knee pain between the groups as measured by VAS and Court-Brown pain scale at 6 months.ConclusionsPatients with stable tibia fractures treated with intramedullary nailing have improved clinical and functional outcomes at 3 months compared with those treated with casting, but there are no differences in any other outcome measure. Patients treated in a cast may have a higher incidence of malalignment or malunion. Level of evidence Level-II prognostic.

Results of a systematic approach to exchange nailing for the treatment of aseptic tibial nonunions.

The purpose of this study was to evaluate the effectiveness of a systematic approach to exchange nailing for the treatment of aseptic tibial nonunion. Retrospective cohort. Tertiary referral center. Forty-six aseptic tibial nonunion sites in 40 patients (2 bilateral and 4 segmental) who presented with an intramedullary nail on an average of 16 months after the initial treatment were presented in this study. Insertion of an exchange nail of at least >2-mm diameter than the prior nail using a different manufacturer's nail, static interlocking, partial fibulectomy in a select group of patients, and correction of underlying metabolic and endocrine abnormalities. Union rate, time to union. Forty-five of 46 tibial nonunion sites (98%) healed at an average of 4.8 months. Patient selection criteria and a systematic approach to exchange nailing for tibial nonunion is highly successful. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A novel micro-controlled dynamic intramedullary nail for tibial middle fracture in Tibet mini-pigs

Objective To explore the effect on the fracture union in Tibet mini-pigs of a novel micro-controlled dynamic intramedullary nail which was self-designed on the basis of anatomic parameters of the animal tibia.Methods We measured the length,arc and inner diameters of the starting,narrowest and ending points of the bilateral tibial medullary cavities on the X-ray films of 20 Tibet mini-pigs.We designed and manufactured a new micro-controlled intramedullary nail using UG software on the basis of the anatomic measurements and CT 3D reconstructions of the animal tibia.The new fixation nails were tested in the animal models of left tibial middle fracture in 10 Tibet mini-pigs which were randomized into 2 groups (n =5).The experiment group was treated with the novel micro-controlled dynamic intramedullary nail and the control group with the static interlocking intramedullary nail.The fracture union was evaluated and compared between the 2 groups by X-ray,gait analysis and micro CT.Results Of the medullary cavity,the triangle proximal end was expansive,the middle segment was narrow and the oval distal end was also expansive in the Tibet mini-pigs.The length of medullary cavity averaged 113.31 ± 9.56 mm and the cavity arc 25.66° ± 3.37°.The nail length was 90 to 130 mm,the nail diameter 6 to 9 mm,the arc 15° to 25°,and the diameter of both locked screw and bioresorbable material 4.0 mm.The micro CT showed that the experimental group had significantly higher volume bone density (555.47 ± 23.49 mg/mm3) and bone volume fraction (0.84 + 0.04) than the control group (494.45 ± 16.62 mg/mm3 and 0.78 ± 0.03 respectively) (P ＜ 0.05).Conclusion It may help fracture union to design a novel micro-controlled dynamic intramedullary nail based on the theory of micro-controlled motion in clinic research. Key words: Bone nails; Fracture fixation, intramedully; Fracture healing; Imaging,three-dimensional

Fractures of the tibia shaft treated with locked intramedullary nail

Abstract Background: The gold standard treatment for complex fractures of tibial shaft is the reamed interlocking intramedullary nail. There has been some controversies about dynamization of statically locked nail, and some authors recommend routine dynamization for promotion of healing. This study evaluates the treatment of complex fractures of tibia shaft with static and dynamic interlocking intramedullary nail method. Methods: In this retrospective study, we studied 100 patients treated in Clinical Emergency Hospital Constanta between April 2012 - July 2013 diagnosed with tibia and fibula shaft fractures. They were treated by external fixation, and intramedullary nail. The intramedullary nail was blocked distally static or dynamic. Results: All patients achieved union during 12-18 weeks. The need of dynamization was required at 23 patients after 10 weeks from osteosynthesis. No significant complication was observed in our patients. Alignment of tibial fracture was perfect in all patients without any shortening and rotation. Conclusion: Locked intramedullary nailing is the treatment of choice for fractures of the tibial shaft.

New Technique: A Novel Femoral Derotation Osteotomy for Malrotation following Intramedullary Nailing

A 19-year-old female patient sustained a closed spiral midshaft femoral fracture and subsequently underwent femoral intramedullary nail insertion. At followup she complained of difficulty in walking and was found to have a unilateral in-toeing gait. CT imaging revealed 30 degrees of internal rotation at the fracture site, which had healed. A circumferential osteotomy was performed distal to the united fracture site using a Gigli saw with the intramedullary femoral nail in situ. The static distal interlocking screws were removed and the malrotation was corrected. Two further static distal interlocking screws were inserted to secure the intramedullary nail in position. The osteotomy went on to union and her symptoms of pain, walking difficulty, and in-toeing resolved. Our paper is the first to describe a technique for derotation osteotomy following intramedullary malreduction that leaves the intramedullary nail in situ.

Technique et expérience initiale de l’arthrodèse tibio-talocalcanéenne postérieure par arthroscopie

Tibiotalocalcaneal arthrodesis is indicated for pain relief in patients with combined arthritis of the ankle and subtalar joint. An arthroscopic posterior approach was designed to improve upon traditional methods by using a minimally invasive technique. The technique involves prone positioning of the patient, one anterolateral and two posterolateral portals, and arthroscopic debridement of both the tibiotalar and posterior talocalcaneal joint. Stabilisation is obtained with a retrograde intramedullary nail, with static interlocking. This article presents illustrative cases and discusses some of the technical advantages and disadvantages over conventional open surgery. For surgeons familiar with posterior ankle or subtalar arthroscopy, this minimally invasive debridement and nailing appears to offer superior exposure, high patient satisfaction and lower postoperative morbidity than traditional methods; fusion is encouraged by preserving the medullary reaming material at the site of the fusion.

Technique and early experience with posterior arthroscopic tibiotalocalcaneal arthrodesis

Tibiotalocalcaneal arthrodesis is indicated for pain relief in patients with combined arthritis of the ankle and subtalar joint. An arthroscopic posterior approach was designed to improve upon traditional methods by using a minimally invasive technique. The technique involves prone positioning of the patient, one anterolateral and two posterolateral portals, and arthroscopic debridement of both the tibiotalar and posterior talocalcaneal joint. Stabilisation is obtained with a retrograde intramedullary nail, with static interlocking. This article presents illustrative cases and discusses some of the technical advantages and disadvantages over conventional open surgery. For surgeons familiar with posterior ankle or subtalar arthroscopy, this minimally invasive debridement and nailing appears to offer superior exposure, high patient satisfaction and lower postoperative morbidity than traditional methods; fusion is encouraged by preserving the medullary reaming material at the site of the fusion.

Influence of intramedullary nail diameter and locking mode on the stability of tibial shaft fracture fixation

Fracture healing is affected by the type and the magnitude of movements at the fracture site. Mechanical conditions will be a function of the type of fracture management, the distance between the fracture fragments, and the loading of the fracture site. The hypothesis to be tested was that the use of a larger-diameter intramedullary nail, together with compressed interlocking, would enhance the primary stiffness and reduce fracture site movements, especially those engendered by shearing forces. Six pairs of human tibiae were used to study the influence on fracture site stability of two different diameters (9 and 11 mm) of intramedullary nails, in tension/compression, torsional, four-point bending, and shear tests. The nails were used with two interlocking modes (static interlocking vs. dynamic compression). With static interlocking, the 11-mm-diameter nail provided significantly (30-59%) greater reduction of fracture site movement, as compared with the 9-mm-diameter nail. Using an 11-mm-diameter nail, the stiffness of the bone-implant construct was enhanced by between 20 and 50%. Dynamic compression allowed the interfragmentary movements at the fracture site to be further reduced by up to 79% and the system stiffness to be increased by up to 80%. On biomechanical grounds, the largest possible nail diameter should be used, with minimal reaming, so as to minimize fracture site movement. Compression after meticulous reduction should be considered in axially stable fractures.

Nailing of Femur Fractures - The Actual Results

This study was a retrospective review to determine the actual results of intramedullary nailing for femur shaft fractures in a trauma hospital. Of 178 consecutive femurs treated with intramedullary nails, 128 fractures could be evaluated at 6 mo. Most fractures were type A. All 128 cases were treated with static interlocking nail. There were 14 (11 %) fractures that did not heal. 50 % of the open fractures and 25 % of the type C fractures did not heal. Opening a fracture to improve reduction was performed 12 times, and all these cases healed without infection.

Pudendal Nerve Palsy Following Static Intramedullary Nailing of the Femur

Objective: To determine the incidence of pudendal nerve palsies following static interlocking nailing of the femur, and to relate its development to age, body mass index, amount of pre-operative shortening, timing of surgery, level and type of fracture, duration of intra-operative traction, and use of muscle relaxants during surgery. Method: Twenty-nine consecutive patients who were treated with intramedullary nailing for femoral shaft fractures were prospectively studied. The age, body mass index, level and type of fracture, pre-operative traction, timing of surgery, preoperative shortening, duration of intra-operative traction, and use of muscle relaxants were recorded. Post-operatively, each patient was examined for altered sensation in the perineum. Men were asked about erectile function. Results: Eight patients (27.6%) developed palsies. All patients regained normal sensation and function. No significant differences were found between pudendal nerve injury and age, body mass index, pre-operative shortening, timing of surgery, level of fracture, muscle relaxant use, and duration of intra-operative traction. Significantly more palsies were present in patients with comminuted fractures. Conclusion: Intramedullary nailing of the femur is associated with pudendal nerve palsy. There is a significant correlation between pudendal nerve palsy and comminuted fractures.

Intramedullary Nailing of Humeral Head and Humeral Shaft Fractures.

There is an increasing interest in intramedullary nailing for humeral fractures. Starting with diaphyseal fractures, now also proximal metaphyseal fractures of the humerus can be nailed with satisfying results. Basic ideas for humeral nailing are less invasive approaches to the humerus, less soft tissue damage, e.g. lower rates of radial nerve palsy, closed reduction and the biomechanical aspects of a central implant with elastic fixation properties. Nailing of diaphyseal humeral shaft fractures is an equivalent alternative to plating; nailing of proximal metaphyseal humeral fractures is still new and needs more reliable scientific data to clear its advantages compared to other fixation techniques. Nailing of distal metaphyseal humeral fractures is no serious option at the moment. Angular stable interlocking systems show better fixation qualities for proximal fractures or fracture components. Although in very osteoporotic bone cutouts are registered. Static interlocking is advisable. High torsional stability of the fracture fixation has to be achieved, since significant torsional load occurs during the usual movement of the upper limbs. As there is an important learning curve, possible complications of intramedullary nailing have to be kept in mind and avoided by a careful operation technique.

A research into early dynamization of interlocking intramedullary nail for treatment of tibial shaft fractures

目的 回顾性研究交锁髓内钉早期动力化后对胫骨干骨折愈合的影响.方法 自2002年1月～2004年9月,采用静力型交锁髓内钉固定治疗32例胫骨干骨折患者,术后6～10周根据骨折情况予以早期动力化,检测骨折愈合情况和并发症,并与同期同样方法固定但未动力化的43例胫骨骨折的随访结果进行比较.结果 所有患者获得4～13个月(平均6.5个月)随访.骨折愈合时间动力化组105～126 d,平均115.6 d,未动力化组119～133 d,平均124.5 d,差异有显著性意义(P＜0.05),髓内钉动力化更有利于胫骨干骨折的愈合.动力化组有2例(6.2%)延迟愈合,未动力化组有4例延迟愈合(9.4%),差异无显著性意义(P＞0.05),动力化后延迟愈合无显著增加.结论 交锁髓内钉早期动力化有利于促进胫骨干骨折的愈合。

Internal Fixation of Diaphyseal Fractures of the Forearm by Interlocking Intramedullary Nail

This study was designed to evaluate the efficacy of the treatment of diaphyseal fractures of the forearm using the ForeSight forearm interlocking intramedullary nail. Retrospective study. University-affiliated teaching hospital. Eighteen patients with 32 displaced diaphyseal forearm fractures were identified. All fractures were treated with the ForeSight forearm interlocking intramedullary nail. Eighteen fractures were stabilized with static interlocking technique. The assessment of patients was based on the time to union, the functional recovery, and the incidence of complications. Physical capability was evaluated by using the rating system of Grace and Eversmann. Patient-rated outcome was assessed by completion of the Disability of Arm Shoulder Hand questionnaire (DASH). All fractures healed with the index procedure. The average time to union for fractures utilizing a closed technique was 10 weeks; for fractures using an open reduction technique, 15 weeks. The mean pronation was 62 (range, 0-96) degrees, and the mean supination was 80 (range, 0-105) degrees. Compared with the normal arm, the mean loss of rotation of the forearm was 32 (range, 5-162) degrees. Using the rating system of Grace and Eversmann, 13 patients had an excellent or good result, 3 had an acceptable result, and 2 had an unacceptable result. Using the patient-rated functional questionnaire, the mean DASH of 19 (range, 4-72) points at the time of the most recent follow-up indicated a mild-to-moderate impairment. There were 7 postoperative complications. The incidence of complications was 22% (7/32). One cross-union between forearm bones occurred in a patient with a closed head injury and high-energy trauma. Two nondriving end screws of the ulna nail backed out causing wrist pain and had to be removed. There were 4 superficial infections occurring all in the fractures that necessitated an open reduction technique. The overall rate of infection was 12.5% (4/32). Three patients who presented with an open fracture needed a skin graft to cover the open wound. Forearm interlocking intramedullary nailing is an acceptable method to stabilize displaced diaphyseal forearm fractures in adult.

Effects of Dynamization with an Interlocking Femur Nail: A Clinical Study

A consecutive, retrospective series of 179 patients with femoral shaft fractures that had been treated by a static interlocking nail was analyzed to determine the rate of union and the time to union in cases of planned conversion from static to dynamic fixation. The results were compared to those obtained with static fixation without dynamization. The dynamized group included 75 patients (12 females and 63 males). There were 62 closed fractures, five type I, and eight type II open fractures. According to the AO classification, 21 fractures were type 32.A (7, 32.A1; 6, 32.A2; 8, 32.A3), 33 were type 32.B (14, 32.B1; 7, 32.B2; 12, 32.B3), and 21 were type 32.C (9, 32.C1; 4, 32.C2; 8, 32.C3). The static group included 104 patients (27 females and 77 males). There were 90 closed fractures, 11 type I, and three type II open fractures. In this group, 47 fractures were type 32.A (11, 32.A1; 14, 32.A2; 2, 32.A3), 42 were type 32.B (10, 32.B1; 20, 32.B2; 12, 32.B3), and 15 were type 32.C (6, 32.C1; 3, 32.C2; 6, 32.C3). The 75 fractures that were dynamized united during an average time of 126 days while those of the static group took 103 days (p = 0.005). Considering single types of fractures, the time to union was significantly shorter in 32.A3 (p = 0.005), 32.B2 (p = 0.005) and 32.B3 (p = 0.004) fractures when dynamization was not performed. In the 32.C group, healing was shorter in the dynamized group for subgroups 32.C1 and 32.C2, without statistical significance. Thus, the static interlocking nail does not inhibit healing in 32.A and 32.B types of fractures, and the average time to union is shorter than in the dynamized group. Conversion to dynamic intramedullary fixation is not routinely necessary but needs to be performed when a persistent gap can interfere with the consolidation process.