Systematic review on the outcomes of poller screw augmentation in intramedullary nailing of long bone fracture

The evolution of poller screws

Compared to other techniques, poller screws with intramedullary nailing are technically simple, practical, and reproducible for the fixation of metaphyseal fractures. In addition, poller screws do not require special instruments or hardware and are minimally invasive. This review takes a historical perspective to evaluate poller screws holistically. A non-systematic search on PubMed was performed using 'Poller screw' or 'Blocking screw' to find early use of poller blocking screws. Relevant references from these primary studies were then followed up. In 1999, Krettek et al. first coined the term poller screws after the small metal bollards that block and direct traffic. Poller screws were introduced as an adjunct to aid the union of metaphyseal long bone fractures during intramedullary nailing. However, as more evidence was published, the true effectiveness of poller screws was not appreciated, leading to split opinions. Through our research, we have built upon our understanding of poller screws, and we present a novel classification of poller screws over the years while exploring our novel technique and what we believe to be the fourth generation of poller screws. Currently, there is a paucity of research focussing on poller screws. However, studying the original evidence regarding poller screws through the most recent articles has demonstrated a confusion of research in this field. Therefore, we suggest a more organised approach to classify the use of poller screws.

Stable elastic nail application with poller K-wire for Irreducible distal radius metaphyseal-diaphyseal Junction fractures in preadolescents: a new operative technique

BACKGROUND

Surgical treatment of irreducible distal radius diaphyseal- metaphyseal junction fractures involves difficulties as the fracture remains too proximal for K-wire fixation and too distal for the elastic stable intramedullary nail. Our study aims to present the clinical results of applying an elastic stable intramedullary nail with a poller K-wire to achieve both reduction and stable fixation.

PATIENTS AND METHODS

A retrospective analysis was performed on 26 patients who underwent ESIN with a poller K-wire for distal radius diaphyseal-metaphyseal region fracture. Reduction parameters such as residual angulation and alignment were evaluated on postoperative follow-up radiographs. Changes in angular and alignment parameters on follow-up radiographs were recorded. Wrist and forearm functions were evaluated at the last follow-up.

RESULT

There were 17 male and nine female patients with an average age of 10.9. The residual angulation in coronal and sagittal planes on immediate postoperative radiographs was 4.0 ± 1.62° and 3.0 ± 1.26°, respectively. The mean translation rate on immediate postoperative radiographs was 6.0 ± 1.98% and 5.0 ± 2.02% in the coronal and sagittal planes, respectively. No change was observed in translation rates in the last follow-ups. The mean angulation in the coronal and sagittal planes measured on 6th-week radiographs was 4.0 ± 1.72°and 3.0 ± 1.16°, respectively. No significant difference was observed in angular changes in the sagittal and coronal planes at the last follow-up (p > 0.05). No tendon injury or neurovascular injury was observed in any of the patients.

CONCLUSION

In the surgical treatment of pediatric DRDMJ fractures, applying ESIN with poller K-wire is an effective, safe, and novel method for achieving reduction and stable fixation.

Biomechanical comparison of distal femoral fracture fixation: Polyaxial vs. uniaxial locking screws with different blocking screw configurations in retrograde femoral nailing

INTRODUCTION

Clinical studies have indicated reduced reliance on blocking screws with the introduction of polyaxial locking nails, yet the biomechanical superiority of polyaxial locking over blocking screws remains unverified, specifically for distal dia-metaphyseal femur fractures.

HYPOTHESIS

We hypothesized that the combination of multiaxial locking using three screws and parallel locking reinforced by two blocking screws would result in superior outcomes compared to utilizing only parallel locking with two screws and one blocking screw.

MATERIALS AND METHODS

Third-generation custom-made femur models representing AO/OTA 32 A1.2 dia-metaphyseal comminuted oblique fractures were divided into four groups (n=10/group). Group A employed distal fixation with three 4.5-mm polyaxial screws. Group B used two parallel locking screws and two blocking screws, Group C used two parallel locking screws and one blocking screw, and Group D used only two parallel screws. Specimens underwent axial and torsional load testing to assess fatigue strength, ultimate strength, axial stiffness (N/mm), torsional stiffness (N/mm/deg), axial load to failure (N), torsional load to failure (N/mm), coronal and sagittal angulations, and fracture site collapse.

RESULTS

Group C exhibited statistically superior torsional stiffness compared to Groups B and D (p=0.039 and p=0.034, respectively). Axial load to failure was highest in Group B and lowest in Group D (p=0.032). Group C demonstrated the highest torsional strength, while Group B exhibited the lowest (p=0.006). Coronal displacement was greatest in Group B, while Group A showed the highest resistance (p=0.009). Group A demonstrated the greatest resistance to fracture site collapse, with the weakest specimens observed in Groups B and C (p=0.01).

DISCUSSION

The performance of a single laterally positioned blocking screw is comparable to using two blocking screws. Medial positioning of a second blocking screw is unnecessary for stability enhancement. Multiaxial locking prevents fracture site collapse and coronal plane angulation more effectively than other methods. Multiaxial locking and/or parallel screws with a single laterally positioned blocking screw provide superior stiffness and stability for treating unstable dia-metaphyseal distal femoral fractures.

LEVEL OF EVIDENCE

N/A.

Poller Screws and Post-Operative Pain Relief in Tibial Fractures

Introduction Poller screws optimise fracture alignment in those fractures managed with intramedullary (IM) nails. They enhance stability, control nail insertion, and prevent translation. Indications encompass acute fractures, delayed unions/non-unions, and deformity. Classified into four generations, they've shown positive outcomes: improved alignment, reduced complications, and shorter healing. However, their pain management impact is understudied. This retrospective cohort study aimed to compare opioid medication needs in tibial fractures managed with IM nails with and without poller screws. Methods Between January 2015 and December 2022, a retrospective analysis was conducted on tibial fractures treated at a major trauma centre. Patients primarily treated with IM nails were included. Patient and operation notes as well as radiographs, were reviewed to identify poller screw utilisation. Opioid medication data was collected and converted to "coverage" (days) and "strength" (morphine milligrams equivalent or MME). Two-tailed independent samples T-tests were performed to determine differences between patients treated with (n=205) and without poller screws (n=540). Results Patients with poller screws had fewer days with opioid prescriptions in the second post-operative month (6.8 vs. 8.9 days, p=0.038) and significantly lower opioid strength requirements across the first post-operative year (688.4 vs. 1295.4 MME, p=0.001), except the first month. Conclusion There is limited research on the connection between poller screws and pain. This study discusses their potential to reduce post-operative pain in tibial fractures. The results highlight the importance of using poller screws alongside IM. This combination appears to be effective in improving post-operative pain management and enhancing overall patient outcomes.

The Use of Blocking Wires in Fibular Intramedullary Nailing of an Ankle Fracture with Hardware Failure: A Case Report

A 24-year-old male, with a body mass index (BMI) of 31.7 and a previous open reduction and internal fixation (ORIF) of the left ankle seven years ago, presented to the emergency department with a peri-implant, comminuted fibula fracture with broken hardware and syndesmotic injury. The nature of the revision surgery made proper guidewire placement during fibular nailing difficult. Blocking wires assisted in ensuring proper guidewire placement. The patient was successfully managed with revision ORIF, fibular nailing, and syndesmotic fixation. Blocking wires are a helpful tool for achieving proper fracture alignment and stability during intramedullary nailing procedures and may be considered in fibular nailing situations.

Updated Blocking Techniques for Lower Extremity Medullary Nailing: Beyond the Concavity of Deformity

Modern blocking techniques are useful to achieve anatomic alignment and stable fixation during end-segment nailing. Whether with screws or drill bits, blocking implants can correct both angular and translational deformities. Understanding the biomechanics of blocking implants allows the surgeon to properly plan their placement based on principles rather than dogma. We use case examples to highlight updates in blocking techniques during acute surgical fixation and chronic deformity correction.

Avoiding deformity in proximal tibial nailing: risk factors, deformity rules, tips, and tricks

Malalignment is one of the most common problems linked to nailing of proximal tibial fractures. This review will cover technical aspects of intramedullary nailing and will help explain the various risk factors. Deformity rules aid in identifying the likely deformity and help to develop management strategies. Various tools and techniques are discussed which can help optimize the outcome.

Level of Evidence

Therapeutic Level V.

In silico biomechanical analysis of poller screw-assisted small-diameter intramedullary nail in the treatment of distal tibial fractures

Objective: To evaluate the biomechanical effects of Poller screws (PS) combined with small-diameter intramedullary nails in the treatment of distal tibial fractures at different locations and on different planes. Methods: Nine finite element (FE) models were used to simulate the placement of the intramedullary nail (IMN) and the PS for distal tibial fractures. Structural stiffness and interfragmentary motion (IFM) through the fracture were investigated to assess the biomechanical effects of the PS. The allowable stress method was used to evaluate the safety of the construct. Results: With the axial load of 500 N, the mean axial stiffness of IMN group was 973.38 ± 95.65 N/mm, which was smaller than that at positions A and B of the coronal group and sagittal group (p < 0.05). The shear IFM of the IMN group was 2.10 ± 0.02 mm, which were smaller than that at positions A and B of the coronal group and sagittal group (p < 0.05). Under physiological load, the stresses of all internal fixation devices and the nail-bone interface were within a safe range. Conclusion: In the treatment of distal tibial fractures, placing the PS in the proximal fracture block can obtain better biomechanical performance. The IMN fixation system can obtain higher structural stiffness and reduce the IFM of the fracture end by adding PS.

Extra-articular Blocking Technique to Resolve Severe Acetabular Bone Defect in Developmental Dysplasia of the Hip

OBJECTIVE

The reconstruction of acetabular bone defect in developmental dysplasia of the hip (DDH) is a great challenge. Although several successful solutions have been raised, their efficacy and reliability have not been fully substantiated. This work aims to present a simple, economic and effective acetabular reconstructive technique to resolve the massive acetabular bone defect in DDH scenario.

METHODS

This is a case series and observational study investigating the effectiveness and safety of extra-articular blocking technique in patients diagnosed as DDH of Crowe type II-III and Hartofilakidis B. Sixteen consecutive patients indicated for extra-articular blocking and treated with total hip arthroplasty were enrolled in this series from January 2019 to August 2020. The outcome measures included the surgical indicators such as acetabular coverage, prosthesis position, operational time, medical cost, and short-term follow-up indicators such as complications profile, patient-reported functional scales, overall recovery after surgery, and radiographic bone integration and remodeling. Their medical documentation and follow-up records were carefully reviewed with ethical approval.

RESULTS

The mean values of postoperative acetabular component inclination and anteversion were 42.3° ± 2.1° and 16.4° ± 1.8°, with an average acetabular coverage of 92.1%. The mean cost reduction for patients treated with this technique compared with those treated with trabecular metal augmentation was 15.3%. The mean time until walking under full-weight bearing decreased by 3.5 weeks compared with patients treated with autologous bone grafting. Within an average observational period of 18 months, the mean improvements in Harris hip score and WOMAC score were 31 and 22 points, respectively, which were identical to those with bone graft and metal augmentation techniques. No complications such as dislocation, acetabular loosening, periprosthetic joint infection, and limb length discrepancy were recorded. No signs of translucent line formation, third-party reaction, and wear-associated osteolysis were identified.

CONCLUSION

The extra-articular blocking can work simply and effectively to address acetabular bone defect in DDH patients of Crowe II-III and Hartofilakidis B, as evidenced by cost-effectiveness and instant weight-bearing advantages, low failure rate, and early osteointegration and remodeling.

Optimal blocking screw placement for retrograde IM nail fixation of distal femur fracture: a standardized biomechanical study of "osteoporotic" synthetic bone

PURPOSE

Intramedullary (IM) nail use for metaphyseal fracture management is problematic in long bones like the femur because the larger medullary cavity allows increased fracture motion and potentially increased implant failure and malunion/nonunion risk; Achieving effective distal femur fracture fixation is even more difficult in osteoporotic bone. Blocking screws to control IM nail movement are known to be effective for tibia fracture management. Few studies have evaluated IM nail and blocking screw use efficacy for distal femur fracture fixation in osteoporotic bone.

METHODS

This study used an osteoporosis simulation synthetic bone model to evaluate retrograde IM nail fixation of a standardized non-comminuted, extra-articular distal femur fracture with and without blocking screws. The hypothesis was that use of one or two blocking screws would increase IM nail fixation stability as evidenced by greater peak IM nail load and lesser movement. A servohydraulic device under displacement control collected loading force versus movement deflection data. Shapiro-Wilk tests confirmed data normality. One-way analysis of variance and Tukey post hoc tests were used to compare condition specific loading force and movement differences.

RESULT

In the coronal plane, blocking screw conditions displayed greater loading ranges (38.3 ± 2 vs. 19.1 ± 2 N, 100.5% difference) (p < 0.0001) and lesser movement (2.0 ± 0.3 vs. 6.86 ± 0.4 mm, 243% difference) (p < 0.0001). In the sagittal plane, the two blocking screw condition displayed a significantly greater loading magnitude (29.9 ± 6 vs. 20.8 ± 2.3 N, 43.8% difference) than the identical control condition without blocking screws (p = 0.018); however, movements were comparable (p = 0.82). Long-axis rotational loading failed to reveal load magnitude differences (p = 0.28); however, two different blocking screw conditions displayed decreased movement (1.32 ± 0.2 vs. 2.05 ± 0.3 mm, 53.8% difference) compared to other conditions (p ≤ 0.018).

CONCLUSIONS

Use of one or two blocking screws on the medial and lateral sides of the IM nail decreased coronal plane movement in the intramedullary canal. Combining retrograde IM nail implantation with blocking screws reduced medial-lateral IM nail movement and increased fracture stability. These characteristics may help prevent fixation failure, malunion, and even nonunion in patients with a distal femur fracture in osteoporotic bone.

Effect of Different Reduction Intramedullary Nails on Spiral Fracture of Middle and Lower Tibia

Objective

To compare the efficacy of different reduction and intramedullary nailing in the treatment of spiral fracture of middle and lower tibia.

Method

A total of 96 patients with spiral fractures of middle and lower tibia treated with intramedullary nails were retrospectively analyzed. The patients were divided into closed functional reduction group, open anatomical reduction group, and closed anatomical reduction group according to different treatment methods. The operation time, intraoperative blood loss, intraoperative fluoroscopy times, fracture healing time, fracture nonunion, wound complications, and healing conditions of the three groups were compared.

Results

The operation time and intraoperative fluoroscopy times of patients in the closed anatomical reduction group were significantly increased compared with those in the closed functional reduction group, while the fracture healing time was significantly reduced. However, patients in the open reduction group had significantly more intraoperative blood loss than those in the closed reduction group. The mean follow-up duration of patients was 15.81 ± 3.25 months. Open anatomical reduction was found to have a higher complication rate during follow-up. Specifically, a total of 3 cases recovered after 2 times of surgical treatment. 6 cases showed a small gap at the fracture end which did not affect the function.

Conclusion

In the treatment of middle and lower spiral fracture of tibia, closed anatomical reduction and intramedullary nail internal fixation have shorter fracture healing time, less blood loss, and fewer complications, which can act as the first surgical choice. However, open reduction and intramedullary nailing have a high complication rate, which is not recommended.

Treatment of ipsilateral femoral neck and shaft fracture by augmented fixation via modified anterior approach: A case report

Case

A 39-year-old man with obsolete fracture of the left femoral neck (AO/OTA31B2.3, Pauwels III) and segmental fracture of the ipsilateral shaft (AO/OTA32C2) caused by traffic accident was treated by a hybrid augmented fixation technique, long reconstruction intramedullary nail combined with medial anatomical buttress plate and poller screws. All procedures were carried out via the modified anterior approach with a good exposure of the fracture site.

Conclusion

The hybrid augmented fixation technique via the modified anterior approach could improve fracture reduction and mechanical stability for ipsilateral femoral neck and shaft fractures.

A New Technique for Placement of Blocking Screws and its Mechanical Effect on Stability of Tibia Fractures with Distal Fragments after Insertion of Small-Diameter Intramedullary Nails

Objective

To design a novel blocking screws (BSs) geometry and insertion method to treat distal tibia fracture with nailing and comparison of mechanical properties of novel and traditional screws.

Methods

Twenty‐one synthetic left tibiae were sectioned to obtain 21 distal segments measuring 55 mm. Intramedullary (IM) 9‐mm tibial nails were advanced to 6 mm from the ankle joint. Two transverse and one anterior–posterior (AP) locking screws were inserted. Both medial–lateral (ML) BSs were placed 10 mm from the topmost interlocking screw. A custom‐made jig assisted in placing the novel and traditional BSs. The time spent in placing each BS was recorded. All the samples were repaired with an IM nail and without BSs, with two traditional BSs, and with two novel BSs. An initial loading from −150 to +150 N was applied to specimens in the ML direction at 185 mm from the nail end, followed by cyclic loading of the same for 10,000 cycles with failure‐to‐test loading of 350 N in the ML direction. The maximum displacement was measured at 80 mm from the nail end and recorded under initial loading. The damage of two kinds of BSs to the nail was recorded.

Results

Compared with average 5.21 min of the time of placing a traditional BS, the time spent in positioning a novel BS on the fracture model was 2.53 min. In the distal bone–implant constructs (BICs), the addition of traditional BSs decreased the maximum displacement of the BICs by 26.2%. The addition of the novel BSs decreased the displacement by 28.9%. All constructs survived 10,000 cycles without hardware deformation. The failure rate of the control group was significantly greater than that of the traditional group; however, the novel group was similar to the traditional group. The damage of the traditional BS to the nail was greater than that of the novel one.

Conclusions

The novel and traditional BSs are comparably effective for increasing the primary mechanical stability of distal metaphyseal fractures after nailin. However, compared to the placement of a traditional BS, implanting a novel BS took more less time and caused less damage to the nail. Additionally, the most obvious advantage of the novel BS design and insertion technology was that the pressure and distance between it and the IM nail could be controlled by rotating the screw. These advantages of the novel BS will be beneficial for clinical application.

Do Poller screws effect union in tibial shaft fractures treated with intramedullary nailing?

INTRODUCTION

Tibial shaft fractures are a commonly encountered challenge presented to orthopaedic trauma surgeons. Intramedullary nailing (IMN) is often the treatment of choice and whilst effective, complications of delayed and/or non-union can cause significant morbidity and necessitate additional operative procedures. The use of Poller screws during IMN are a recognised way of aiding fracture reduction, however the clinical benefits of this are debated. This study evaluated the outcome of tibial shaft fractures treated with IMN with or without the addition of Poller screws.

METHODS

Retrospective cohort study of all patients undergoing IMN following tibial shaft fractures over a 5-year period. 154 operated tibial shaft fractures were identified, with patients divided into 3 groups - Group 1: IM nailing alone, Group 2: IMN + 1 conventional Poller screw, or Group 3: IMN + 2 Poller screws placed Epicentrically across the fracture site. Data collected included demographics, length of stay, fracture type, position and AO classification grade, operative time, and operating surgeons' grade. Primary outcome measure was the incidence of delayed and/or non-union. Secondary outcomes were differences in rates of infection and additional orthopaedic procedures between the 3 groups.

RESULTS

Overall 139/154 fractures (90.3%) achieved a timely union. There was a statistically significant difference (p = 0.05) in fracture union between the 3 groups, with 75/88 fractures healing in group 1 (IMN alone) compared to 44/46 in Group 2 (IMN + 1 Poller screw) and 20/20 in group 3 (IMN + 2 Poller screws). There was no statistical difference in the incidence of superficial infection, (p = 0.95) additional procedures (p = 0.23) or deep infection (p = 0.65) between the 3 groups.

CONCLUSION

The addition of Poller screws appear to be a safe and effective adjunct in the treatment of tibial shaft fractures via IMN. Further prospective randomised trials are needed to fully elucidate both the role and potential benefits of Poller screw augmentation in acute lower limb fracture management.

Poller (blocking) screw with intramedullary femoral nailing for subtrochanteric femoral non-unions: clinical outcome and review of concepts

INTRODUCTION

Surgery to treat nonunion resulted from malalignment is challenging since correction and bone union should be achieved simultaneously. To report the clinical outcomes achieved through reconstruction of sub-trochanteric femoral fractures by femoral nailing using a poller screw and to review the current concepts.

MATERIALS AND METHODS

Fourteen patients (11 men and 3 women; mean age 56.4 years) who were diagnosed with non-union of subtrochanteric femoral fractures and who underwent intramedullary nailing with blocking screws between August 2013 and March 2019, with at least 1 year follow-up, were analyzed retrospectively. The preoperative and postoperative Centrum-Collum-Diaphyseal angle and anterior angulation angle were measured. Bone union time, position and number of poller screws used, and complications were analyzed. Functional assessment was performed by evaluating the Harris hip score. The related literature was searched, and 14 clinical studies on the treatment of sub-trochanteric non-union were analyzed.

RESULTS

Bone union was achieved in 12/14 cases (85.7%) at the final follow-up within a mean of 6.52 (3-12) months. Bone union was also achieved in two patients lacking bone union at the final follow-up through bone grafting and augmented plating. No cases developed complications, including infection and bone necrosis, and the varus deformity and anterior angulation significantly improved from a preoperative mean of 12.4° and 9.4° to postoperative mean 3.8° and 2.4°, respectively. The mean Harris hip score at the final follow-up was 87.07 (73-98) points. Analysis of published literature revealed high rates of bone union (78-100%) through various fixation methods.

CONCLUSION

Correction with blocking screws and rigid fixation with intramedullary nailing to treat sub-trochanteric-non-union-caused malalignment can yield good clinical and radiological outcomes.

Outcome Analysis of Intramedullary Nailing Augmented with Poller Screws for Treating Difficult Reduction Fractures of Femur and Tibia: a Retrospective Cohort Study

Purpose

Poller screws may serve as an adjunctive reduction tool and aid fracture reduction while augmented with intramedullary (IM) nailing for treating diaphyseal or metaphyseal fractures of the femur and tibia. However, there is no consistent conclusion about whether the method of using IM nailing augmented with poller screws is more advantageous than using IM nailing alone.

Methods

A total of 96 patients who received IM nailing with or without supportive poller screw for treating long-bone fractures in lower limbs and who experienced difficulties in performing reduction or IM insertion during the surgical process were included in this retrospective cohort study (33 patients with poller screws in group A versus 63 patients without poller screws in group B). Patient demographics including age, gender, and body mass index; injury-related data including fracture location, classification, and injury mechanism; operation-related data including American Society of Anesthesiologists, duration of operation, poller screw time, method of anesthesia, and volume of intraoperative hemorrhage; outcomes including fracture healing time; and incidence of outcomes of nonunion, malunion, infection, and secondary surgical procedures were evaluated.

Results

Fracture healing time of patients in group A was significantly shorter than that of group B (18.3 ± 4.8 weeks versus 24.3 ± 3.0 weeks, p = 0.023). Union rate was higher (100.0% versus 87.3%, p = 0.048), and malunion rate and secondary surgical procedure rate were lower (both are 3.0% versus 19.0%, p = 0.031) in group A than that of group B.

Conclusion

Poller screw augmentation of IM nailing is a favourable option to shorten fracture healing time and to reduce complication rates in terms of nonunion, malunion, and secondary surgical procedure in the treatment of both diaphyseal/metaphyseal fractures of the femur or tibia while compare with those treated by IM nailing alone.