Biomechanical comparison of locked plate osteosynthesis, reamed and unreamed nailing in conventional interlocking technique, and unreamed angle stable nailing in distal tibia fractures

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.

Cerclage Wiring Improves Biomechanical Stability in Distal Tibia Spiral Fractures Treated by Intramedullary Nailing

BACKGROUND

Partial weight-bearing after operatively treated fractures has been the standard of care over the past decades. Recent studies report on better rehabilitation and faster return to daily life in case of immediate weight-bearing as tolerated. To allow early weight-bearing, osteosynthesis needs to provide sufficient mechanical stability. The purpose of this study was to investigate the stabilizing benefits of additive cerclage wiring in combination with intramedullary nailing of distal tibia fractures.

METHODS

In 14 synthetic tibiae, a reproducible distal spiral fracture was treated by intramedullary nailing. In half of the samples, the fracture was further stabilized by additional cerclage wiring. Under clinically relevant partial and full weight-bearing loads the samples were biomechanically tested and axial construct stiffness as well as interfragmentary movements were assessed. Subsequently, a 5 mm fracture gap was created to simulate insufficient reduction, and tests were repeated.

RESULTS

Intramedullary nails offer already high axial stability. Thus, axial construct stiffness cannot be significantly enhanced by an additive cerclage (2858 ± 958 N/mm NailOnly vs. 3727 ± 793 N/mm Nail + Cable; p = 0.089). Under full weight-bearing loads, additive cerclage wiring in well-reduced fractures significantly reduced shear (p = 0.002) and torsional movements (p = 0.013) and showed similar low movements as under partial weight-bearing (shear 0.3 mm, p = 0.073; torsion 1.1°, p = 0.085). In contrast, additional cerclage had no stabilizing effect in large fracture gaps.

CONCLUSIONS

In well-reduced spiral fractures of the distal tibia, the construct stability of intramedullary nailing can be further increased by additional cerclage wiring. From a biomechanical point of view, augmentation of the primary implant reduced shear movement sufficiently to allow immediate weight-bearing as tolerated. Especially, elderly patients would benefit from early post-operative mobilization, which allows for accelerated rehabilitation and a faster return to daily activities.

Optimal Design and Biomechanical Analysis of a Biomimetic Lightweight Design Plate for Distal Tibial Fractures: A Finite Element Analysis

The treatment of fractures of the distal tibia can be problematic due to the insubstantial soft-tissue covering this part of the anatomy. This study investigates a novel strategy for minimally invasive plate osteosynthesis of distal tibia fractures called bionic lightweight design plating. Following the structure of the animal trabecular bone, we utilized topological mathematical methods to redesign the material layout of the internal fixation device to fulfill the desired lightweight design within given boundary conditions. The results showed that this method can maintain the same stability of the construct as the original plate after a reduction in the original volume by 30%, and the differences in strain energy of plates and maximum node displacement of constructs between the constructs [RP construct vs. LP construct] were not statistically significant (p > 0.05). In the safety assessment of the constructs, the peak stress of plates between constructs was found to not be statistically significantly different under a doubled physiological load (p > 0.05). The average stress of the plates’ elements exceeding the allowable stress was analyzed, and no statistically significant differences were found between the two constructs under axial compression stress conditions (p > 0.05). The average stress of the plates’ elements in the redesigned plating construct under torsional stress conditions was 3.08% less than that of the locked plating construct (p < 0.05). Under the double physiological load condition, 89% of the elements of the plate in the redesigned plating construct and 85% of the elements of the plate in the locked plating construct were lower than the maximum safe stress of the plate, which was 410 MPa (secondary allowable stresses). That reminds us the topology optimization offer a possible way to improve the capacity of soft tissue protection while ensuring the safety of the RP construct by reducing the volume of the implants.

Strategies to Improve Bone Healing: Innovative Surgical Implants Meet Nano-/Micro-Topography of Bone Scaffolds

Successful fracture healing is dependent on an optimal mechanical and biological environment at the fracture site. Disturbances in fracture healing (non-union) or even critical size bone defects, where void volume is larger than the self-healing capacity of bone tissue, are great challenges for orthopedic surgeons. To address these challenges, new surgical implant concepts have been recently developed to optimize mechanical conditions. First, this review article discusses the mechanical environment on bone and fracture healing. In this context, a new implant concept, variable fixation technology, is introduced. This implant has the unique ability to change its mechanical properties from “rigid” to “dynamic” over the time of fracture healing. This leads to increased callus formation, a more homogeneous callus distribution and thus improved fracture healing. Second, recent advances in the nano- and micro-topography of bone scaffolds for guiding osteoinduction will be reviewed, particularly emphasizing the mimicry of natural bone. We summarize that an optimal scaffold should comprise micropores of 50–150 µm diameter allowing vascularization and migration of stem cells as well as nanotopographical osteoinductive cues, preferably pores of 30 nm diameter. Next to osteoinduction, such nano- and micro-topographical cues may also reduce inflammation and possess an antibacterial activity to further promote bone regeneration.

The role of mechanical stimulation in the enhancement of bone healing

The biomechanical environment plays a dominant role in the process of fracture repair. Mechanical signals control biological activities at the fracture site, regulate the formation and proliferation of different cell types, and are responsible for the formation of connective tissues and the consolidation of the fractured bone. The mechanobiology at the fracture site can be easily manipulated by the design and configuration of the fracture fixation construct and by the loading of the extremity (weight-bearing prescription). Depending on the choice of fracture fixation, the healing response can be directed towards direct healing or towards indirect healing through callus formation. This manuscript summarizes the evidence from experimental studies and clinical observations on the effect of mechanical manipulation on the healing response. Parameters like fracture gap size, interfragmentary movement, interfragmentary strain, and axial and shear deformation will be explored with respect to their respective effects on fracture repair. Also, the role of externally applied movement on the potential enhancement on the fracture repair process will be explored. Factors like fracture gap size, type and amplitude of the mechanical deformation as well as the loading history and its timing will be discussed.

Intramedullary nailing of extra-articular distal tibial fractures

AIMS

The aim of this study was to determine the immediate post-fixation stability of a distal tibial fracture fixed with an intramedullary nail using a biomechanical model. This was used as a surrogate for immediate weight-bearing postoperatively. The goal was to help inform postoperative protocols.

METHODS

A biomechanical model of distal metaphyseal tibial fractures was created using a fourth-generation composite bone model. Three fracture patterns were tested: spiral, oblique, and multifragmented. Each fracture extended to within 4 cm to 5 cm of the plafond. The models were nearly-anatomically reduced and stabilized with an intramedullary nail and three distal locking screws. Cyclic loading was performed to simulate normal gait. Loading was completed in compression at 3,000 N at 1 Hz for a total of 70,000 cycles. Displacement (shortening, coronal and sagittal angulation) was measured at regular intervals.

RESULTS

The spiral and oblique fracture patterns withstood simulated weight-bearing with minimal displacement. The multifragmented model had early implant failure with breaking of the distal locking screws. The spiral fracture model shortened by a mean of 0.3 mm (SD 0.2), and developed a mean coronal angulation of 2.0° (SD 1.9°) and a mean sagittal angulation of 1.2° (SD 1.1°). On average, 88% of the shortening, 74% of the change in coronal alignment, and 75% of the change in sagittal alignment occurred in the first 2,500 cycles. No late acceleration of displacement was noted. The oblique fracture model shortened by a mean of 0.2 mm (SD 0.1) and developed a mean coronal angulation of 2.4° (SD 1.6°) and a mean sagittal angulation of 2.6° (SD 1.4°). On average, 44% of the shortening, 39% of the change in coronal alignment, and 79% of the change in sagittal alignment occurred in the first 2,500 cycles. No late acceleration of displacement was noted.

CONCLUSION

For spiral and oblique fracture patterns, simulated weight-bearing resulted in a clinically acceptable degree of displacement. Most displacement occurred early in the test period, and the rate of displacement decreased over time. Based on this model, we offer evidence that early weight-bearing appears safe for well reduced oblique and spiral fractures, but not in multifragmented patterns that have poor bone contact. Cite this article: Bone Joint J 2021;103-B(2):294-298.

Improvement of clinical fracture healing - What can be learned from mechano-biological research?

The most significant predictors of reoperation following operative management of fractures are the presence of a third degree open fracture, remaining fracture gaps and a transverse fracture. However clinical studies provide no information regarding the involvement of various soft tissues or how the mechanical environment affects revascularisation and bone healing. Here the results of experimental and numerical mechano-biological studies on fracture healing are summarized to provide guidance toward clinical treatment of fractures. In experimental studies, isolated muscle crush appeared to only temporarily impair fracture healing, with no significant effect to the final bone healing, whereas a more severe muscle trauma significantly reduced callus formation and biomechanical properties of the healed bones. An intraoperative trauma can furthermore impede vascularization. Surgical removal of the haematoma or periosteum disturbs fracture healing. While reaming for intramedullary nailing reduced blood flow in the bone during the early phase of bone healing, it did not affect the stiffness or strength of the final bone healing. The optimal conditions for rapid vascularization and bone healing result from fracture fixation that minimizes shearing movements in the healing zone while allowing moderate compressive movements. Bone healing is increasingly delayed with increasing fracture gap size and critical-size defects do not heal sufficiently independent of the mechanical environment. The stiffness of fracture fixation systems like nails and external fixators applied in clinical treatments frequently display a too low stiffness, whereas plate systems often cause a too stiff fixation that suppresses bone healing.

Fixation of distal tibia fracture through plating, nailing, and nailing with Poller screws: A comparative biomechanical-based experimental and numerical investigation

The goal of this study was to investigate two commonly used methods of fixation of distal metaphyseal tibia fractures, plating and nailing as well as the less frequently employed nailing with Poller screws, from a biomechanical perspective. Despite numerous studies, the best method to repair fractures of tibia the remains up for of debate. This study includes an in vitro experimental phase on human cadaveric tibias followed by a finite element analysis. In the experimental phase, under partial weight-bearing axial loading, the axial stiffness of the bone-implant construct and interfragmentary movements for each of the fixation methods, bone-plate, bone-nail, and bone-nail-Poller screw, were measured and compared with each other. Shear interfragmentary movement and stress distribution in the bone-implant construct for the three mentioned fixation methods were also determined from FE models and compared with each other. Results of in vitro experiments, i.e., the exertion of axial loading on the tibia-plate, tibia-nail, and tibia-nail-Poller screw, showed that utilization of tibia-nail and tibia-nail-Poller screw led to a stiffer bone-implant construct, and consequently, lower interfragmentary movement, compared to the tibia-plate construct ( p values for tibia-nail and tibia-nail-Poller screw, and for both axial stiffness and interfragmentary movement, compared to those of tibia-plate construct, were less than 0.05). Numerical analyses showed that nailing produced less undesirable shear interfragmentary movement, compared to the plating, and application of a Poller screw decreased the shear movements, compared to tibia-nail. Furthermore, using the finite element analysis, maximum von Mises stress of adding a screw in tibia-nail, tibia-plate, and tibia-nail-Poller screw, was found to be: 51.5, 78.6, and 60.5 MPa, respectively. The results of this study suggested that from a biomechanical standpoint, nailing both with and without a Poller screw is superior to plating for the treatment of distal tibia fractures.

Outcome and complications of distal tibia fractures treated with intramedullary nails versus minimally invasive plate osteosynthesis and the role of fibula fixation

INTRODUCTION

Distal tibia fractures have been managed conservatively as well surgically. A large number of implants have been used for surgical management of these fractures. No treatment method or implant has been proven to be superior to others. In this prospective comparative study, the complications and outcome of distal tibia fractures managed with intramedullary nails and minimally invasive plate osteosynthesis has been compared. Further, the role of fibula fixation in these fractures has been evaluated.

MATERIALS AND METHOD

One hundred and fifty-four patients of distal tibia fractures with concomitant fibula fractures were randomized into 4 treatment groups based on predetermined inclusion criteria. Functional outcome in these groups was compared based on AOFAS score at 1 year. Intra-operative, post-operative parameters as well as radiological alignment, complications and the need for reoperation were also compared in these groups.

RESULT

The functional outcome in all four treatment groups was similar. The duration of surgery and radiation exposure was higher with minimally invasive plate osteosynthesis. There was no improvement in outcome with plating of fibula. However, fixation of fibula improved the rotational alignment in distal tibia fractures.

CONCLUSION

Although there is no difference in outcome of distal tibia fractures with either nailing or minimally invasive plating, nailing is recommended for closed displaced extraarticular fractures. Fixation of fibula should not be done routinely but should be reserved only for a few specific fracture patterns.

Hidden blood loss and the influential factors after intramedullary nail fixation of extra-articular tibial fractures - a retrospective cohort study

PURPOSE

There were few reports in the literature about the hidden blood loss (HBL) after intramedullary nail (IMN) fixation for extra-articular tibial fractures. Our purpose was to evaluate the amount of hidden blood loss after intramedullary nail fixation for extra-articular tibial fractures, meanwhile, identified the influential factors causing HBL.

METHODS

From January 2015 to December 2017, 122 consecutive extra-articular tibial fracture patients fixed with IMN and 96 met all inclusion criteria for the chosen analysis. Preoperative hematocrit (Hct) levels on admission and postoperative Hct levels on the third day after surgery to calculate the amount of HBL.

RESULTS

The mean HBL was 473.29 ± 102.75 ml after IMN fixation of extra-articular tibial fractures, the multiple regression analysis showed gender, surgical duration, and the diameter of the medullary cavity at the narrowest part of the tibia had an independent influence on HBL.

CONCLUSIONS

A significant amount of postoperative HBL has occurred after IMN fixation of extra-articular tibial fractures. Surgeons should be aware that more HBL can be developed in patients who have male sex, small medullary cavity, and long-time surgical duration. HBL deserves attention to ensure patients' safety in the perioperative period of IMN fixation for extra-articular tibial fractures.

Intramedullary Nailing Versus Minimally Invasive Plate Osteosynthesis for Distal Tibial Fractures: A Systematic Review and Meta-Analysis

To evaluate the application, safety and efficacy of the patients treated with intramedullary nailing (IMN) and minimally invasive plate osteosynthesis (MIPO) in distal tibia fractures. Following the Preferred Reporting Items for Systematic Reviews and Meta Analysis (PRISMA) guidelines, we searched databases PubMed, Cochrane library, EMBASE and Web of Science from inception of the database up to 10 October 2018, using the keywords "distal tibia fractures", "plate", "intramedullary nailing" and "RCT" to identify randomized clinical trials about distal tibia fractures. The included studies were assessed by two researchers according to the Cochrane risk-of-bias criteria. The primary outcome of measurement included operation time, malunion rate, nonunion/delayed union rate, and wound complication. Data analysis was conducted with Review Manager 5.3 software. A total of 10 RCTs involving 911 patients fulfilled the inclusion criteria with 455 patients in the IMN group and 456 patients in the MIPO group. There were no significant differences in radiation time, nonunion or delayed union rate, union time and operation time between the two groups. Patients treated with MIPO had lower incidence of malunion compared with IMN (RR = 1.85, 95%CI: 1.21 to 2.83, P = 1.00), while IMN seemed to have lower surgical incision complications whether in closed or opening fractures (RR = 0.49, 95%CI 0.33 to 0.73, P = 0.43). But in patients classified as 43A, the result of subgroup analysis suggested that there was no significant inwound complication between the two groups. MIPO was superior in preventing malunion compared with IMN, and intramedullary nailing appeared to have lower wound complications. However, in patients with 43A distal tibial fractures, MIPO was more recommended for its prevention of malunion. No matter which method we choose, we should notice and prevent the associated complications.

[Evolution and principles of intramedullary locked nailing]

Key factors for successful osteosynthetic fracture stabilization are anatomical fracture reduction, restoration of axis and torsion alignment as well as tissue-preserving operative techniques. In long bone fractures, the use of intramedullary long bridging nailing offers ideal conditions for bone healing, as axial and rotational stability is provided by canal-filling nails and locking screws. In addition, the tissue in the fracture region is protected as the intramedullary nail insertion is distant from the fracture. The indication spectrum for modern intramedullary locked nailing includes diaphyseal fractures of long bones, metaphyseal fractures and reconstructions, as well as treatment of nonunion, osteotomy and arthrodesis of the lower extremities. Continuous improvements in nail design and instrumentation as well as the introduction of anatomical reconstruction nails will optimize the spectrum and effectiveness of intramedullary osteosynthesis even further.

Extreme Nailing: Is It Safe to Allow Immediate Weightbearing After Intramedullary Nail Fixation of Extra-articular Distal Tibial Fractures (OTA/AO 43-A)?

OBJECTIVES

To determine whether immediate weightbearing after intramedullary (IM) fixation of extra-articular distal tibial fractures (OTA/AO 43-A) results in a change in alignment before healing.

DESIGN

Retrospective review.

SETTING

Level 1 trauma center.

INTERVENTION

IM nailing of distal tibial fractures.

PATIENTS/PARTICIPANTS

Fifty-three patients with 54 fractures, all of whom could bear weight as tolerated postoperatively. Eighteen fractures were OTA/AO 43-A1, 20 OTA/AO 43-A2, and 16 OTA/AO 43-A3; 20 fractures were open.

MAIN OUTCOME MEASUREMENTS

Change in fracture alignment or loss of position.

RESULTS

Average change from initial angulation at final follow-up was 0.52 ± 1.49 degrees of valgus and 0.48 ± 3.14 degrees of extension. Final alignment was excellent in 14, acceptable in 28, and poor in 12; 2 fractures went from acceptable initial alignment to poor final alignment; and 2 fractures went from excellent to acceptable alignment. Seven fractures had an improvement in alignment over time. Two fractures required free-flap coverage and 4 required staged grafting because of bone loss. Ten fractures had an unplanned return to the operating room (5 for infected nonunion requiring implant exchange, 3 for infection requiring debridement without implant revision, and 2 for aseptic nonunion). No patient had revision for implant failure.

CONCLUSIONS

Immediate weightbearing after IM fixation of extra-articular distal tibial fractures (OTA/AO 43-A) led to minimal change in alignment and seems to be safe for most patients. Complications were consistent with those reported in previous non-weightbearing cohorts.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Comparison of plate and intramedullary nail fixation of extra-articular tibial fractures: A retrospective study exploring hidden blood loss

PURPOSE

To explore the hidden blood loss (HBL) in treatment of extra-articular tibial fractures with plate and intramedullary nail fixation.

METHODS

We conducted a retrospective study including 209 consecutive patients treated by plate (Group LCP) or intramedullary nail fixation (Group IMN) for extra-articular tibial fractures between January 2015 to December 2017. Demographics, intraoperative data, perioperative laboratory values, transfusion rate, and early complications were collected and analyzed.

RESULTS

Of 209 patients, 96 patients fixed with IMN and 113 fixed with LCP. The average HBL was 272.71 ± 57.88 ml in Group LCP and 507.66 ± 109.81 ml in Group IMN, and there was statistical difference in the HBL between two groups (p < 0.001). The Hb and Hct loss, surgical duration, and postoperative number of anemic patients in Group IMN were significantly higher than in Group LCP (p < 0.001), and IMN fixation has a significantly higher rate of transfusion (p = 0.027), whereas patients in group IMN has significantly less VBL (p < 0.001), shorter postoperative hospital stay (p < 0.001), and less superficial infection (p = 0.014).

CONCLUSIONS

There was a significant amount of hidden blood loss after reamed intramedullary nail fixation for extra-articular tibial fractures, which was much higher than expected. In view of the morbidity of acute anaemia and transfusion, we suggest that for patients who suffer from extra-articular tibial fractures with multiple injuries, or those with low haemoglobin preoperatively, plates might be more suitable than nail fixation.

Extra-articular distal tibia fractures-controversies regarding treatment options. A single-centre prospective comparative study

Distal tibia fractures are reported to have a high complication rate pre-operatively as well as post-operatively, which can include open fractures, soft tissue damage, infection, malalignment, pseudarthrosis and ankle arthrosis. The operative treatment for the extra-articular distal tibia fractures is a controversial topic in the orthopaedic literature. Some of these fractures are proximal enough to be treated with an intramedullary nail while others are too distal for that. The aim of our study was to compare the results we have had with intramedullary nail (IMN) and minimally invasive plate osteosynthesis (MIPO) in distal metaphyseal (extra-articular) tibia fractures. The study was designed prospectively between January 2013 and March 2016 and took place on the Orthopaedics and Traumatology ward of a Clinical Emergency County Hospital in western Romania. The follow-up visits were scheduled one month, three months and six months post-operatively. For evaluating the ankle function, we used the Olerud-Molander ankle score (OMAS) and union was evaluated at six months on ankle X-rays. At the six-month follow-up visit the average scores were 75.55 (20-100) for the IMN lot and 74.23 (20-90) for the MIPO lot, without finding any statistical difference between the two groups (p >0.1). At the six-month follow-up, X-ray union was objected in 48 (90.5%) of our patients, the IMN lot having worse results (85.18%) than the MIPO lot (96.15%). The results we encountered showed little to no statistical difference when it comes to the functional score we used (OMAS score), leading us to believe that you can achieve comparable results with both implants.

Two Stage Minimally Invasive Method with Locking Plate Application on Distal Tibia Fractures - Our Experience

INTRODUCTION:

In the past distal tibia fractures, including intraarticular fractures, frequently led to poor functional outcomes. The Ruedi-Allgower four steps open method, and later the Patterson and Sirkin recommendations for delayed operative treatment has made a drastic advancement in the treatment of these fractures. The two-stage minimally-invasive protocol using locking plate fixation proved a historical turning point, improving functional results to the highest levels compared to all other methods.

AIM:

To present the superior results of the two-stage minimally-invasive method using locking plate fixation, making this a historic step forward in treating distal tibia fractures.

MATERIAL AND METHODS:

A prospective longitudinal study, collecting data from Traumatology-Clinic in the 2014-2016 periods, available for nine-month follow-up. Twenty-three patients were finally included in the study.

RESULTS:

In analysing the data collected, we focused our attention on the final functional outcomes as indicated by dorsiflexion nine months after injury and also according to the AOFAS Ankle-Hindfoot Scale. Results were excellent with no or minimal consequences. Where complications were present, these were benign and did not require further surgery.

CONCLUSION:

We believe this modern method for the treatment of distal tibia fractures should be applied routinely and considered as the gold standard in this domain.

Minimally invasive percutaneous plates versus conventional fixation techniques for distal tibial fractures: A meta-analysis

OBJECTIVE

This meta-analysis was performed to determine the effects of minimally invasive percutaneous plate osteosynthesis (MIPO) versus conventional fixation techniques (CFT) for treating distal tibial fractures.

METHODS

A literature search was performed in EMBASE, Medline, the Cochrane Library, and Web of Science. The trials searched were evaluated for eligibility. The Cochrane Collaboration's Review Manager software was used to perform meta-analyses.

RESULTS

Eight studies were enrolled, including five randomized controlled trials, one control-matched trial and two retrospective cohort trials. The meta-analysis revealed that MIPO has a longer operating time, longer radiation time and higher incidence rate of soft tissue irritation symptoms than those of CFT. There was no significant difference between the two techniques with regard to union time, the American Orthopedic Foot and Ankle Society (AOFAS), infection rate and various other complications.

CONCLUSIONS

The present meta-analysis showed that MIPO did not have obvious advantages over CFT in the treatment of distal tibia fracture. However, more rigorous randomized controlled trials are required in the future.

Biomechanical effects of angular stable locking in intramedullary nails for the fixation of distal tibia fractures

Treatment of distal tibia shaft fractures using intramedullary nailing requires stable fixation of the distal fragment to prevent malunion. Angular stable locking for intramedullary nails pledge to provide increased mechanical stability. This study tested the hypothesis that intramedullary nails with angular stable interlocking screws would have increased construct stiffness, reduced fracture gap movement and enhanced fatigue failure compared to nails with conventional locking having the same diameter. Biomechanical experiments were performed on 24 human cadaveric tibiae which obtained a distal fracture and were fixed by three different techniques: conventional locking with 8- and 10-mm-diameter nails and angular stable locking with 8-mm nails. Stiffness of the implant–bone construct and movement of the fragments were tested under axial loading and torsion. The constructs were tested to failure under cyclic fatigue loading. Analysis of variance and Kaplan–Meier survival analysis were used for statistical assessment. Axial stiffness of the 10-mm nail was about 50% larger compared to both 8-mm nail constructs independent of the type of locking mode (p < 0.01). No differences were found in axial performance between angular stable and conventional locking neither under static nor under cyclic testing conditions (p > 0.5). Angular stability significantly decreased the clearance under torsional load by more than 50% compared to both conventionally locked constructs (p = 0.03). However, due to the larger nail diameter, the total interfragmentary motion was still smallest for the 10-mm nail construct (p < 0.01). Although the 10-mm nail constructs survived slightly longer, differences between groups were minor and not statistically significant (p = 0.4). Our hypothesis that angular stable interlocking of intramedullary nails would improve mechanical performance of distal tibia fracture fixation was not confirmed in a physiologically realistic loading scenario. Whether minor mechanical advantages provided by angular stability of the locking screws would improve biological tissue response cannot be concluded from this biomechanical study.

Metaphyseal Distal Tibia Fractures: A Cohort, Single-Surgeon Study Comparing Outcomes of Patients Treated With Minimally Invasive Plating Versus Intramedullary Nailing

OBJECTIVES

The purpose of this study was to compare clinical and functional outcomes of patients with distal tibia fractures treated with minimally invasive plating (MIPO) or intramedullary nailing (IMN).

DESIGN

Cohort study.

SETTING

Level II regional trauma center.

PATIENTS

Overall, 86 patients with metaphyseal distal fractures (within 5 cm of joint) with simple or no articular involvement treated by a single, fellowship trained, orthopedic trauma surgeon from 2002 to 2013.

INTERVENTION

Intramedullary nailing or minimally invasive plate osteosynthesis.

MAIN OUTCOME MEASURES

Clinical and radiographic results were evaluated at a minimum of 1-year follow-up. Limb-specific outcomes (American Orthopedic Foot and Ankle Surgeons' ankle-hindfoot instrument) and whole-person measures [Short Form 36 (SF-36) instrument] were assessed at the final follow-up.

RESULTS

We studied 86 patients with distal tibia fractures treated with MIPO (43 patients) and IMN (43 patients). Thirty-seven patients in the MIPO group and 27 in the IMN group met inclusion criteria. All patients ultimately healed, with the average time to union of 23 weeks in both the groups. Complications were similar between the 2 groups (MIPO vs. IMN, respectively), including nonunion (8% vs. 7%), malalignment (3.6% vs. 3%), wound complications (3.6% vs. 3%), and infection (0% vs. 3.6%). The need for secondary procedures for the removal of implants was 25.9% in the IMN group (distal locking screws only in 6/7) versus 8.3% in the MIPO group (P = 0.05). Additionally, the American Orthopedic Foot and Ankle Surgeons and all SF-36 version 2 domain scores were quantitatively higher for the IMN group, although only Role Emotional reached a level of statistical superiority between the groups.

CONCLUSIONS

Similar clinical results and marginally enhanced functional outcomes were seen when treating nonarticular or minimally articular metaphyseal distal tibia fractures with IMN compared with MIPO. However, patients treated with IMN required more frequent secondary surgeries for the removal of painful distal locking screws.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

[Intramedullary nailing of the distal tibia. Does angular stable locking make a difference?]

BACKGROUND

Osteosynthesis of distal tibia fractures relies on stable fixation of the distal fragment. Modern intramedullary implants provide various fixation options for locking screws. These implants expand the indications for intramedullary nailing of tibia fractures towards more distally located fractures.

MATERIAL AND METHODS

The most essential options which improve the fixation of the distal fragment include an increase in number, in size and in spacing of the distal locking screws. Further options for nailing of distal tibia fractures include interfragmentary compression and angular stability. Interfragmentary compression considerably increases mechanical stability in axially stable fracture situations. Angular stable fixation of the locking screws has recently become a popular feature in intramedullary nailing; however, the effect of angular stability on the mechanical properties of distal tibia osteosynthesis has been found to be limited.

CONCLUSION

The initial stability to provide sufficient load bearing capacity appears to be provided by the available locking options. With at least two screws, preferably in crossed configuration and spaced over the largest available distance of the distal fragment, secure and stable fixation can be achieved. Insertion of the locking screws in a free hand technique typically results in jamming of the locking screw with the nail and with cortical bone, providing inherent angular stability of the construct. Angular stable locking features of the nail itself do not appear to improve mechanical stability or to affect healing of distal tibia fractures.

Biomechanical evaluation of intramedullary nail and bone plate for the fixation of distal metaphyseal fractures

Surgical treatment of distal metaphyseal fractures remains problematic, and whilst both intramedullary nailing and bone plate fixation are known as the acceptable methods for the internal fixation of this kind of fractures, neither technique demonstrated satisfactory clinical outcomes. In this research, a finite element based investigation was made to compare these two fixation techniques for the fixation of distal tibia fractures from the biomechanics point of view. For this purpose, a 3mm transverse fracture gap was created at the distal metaphyseal region of tibia and fixed by use of either a nail or a plate. The von Mises stress, interfragmentary movements, and the production of different tissue phenotypes at the fracture site were calculated. Results of this study showed that plating offers more advantageous biomechanical conditions at the fracture site, in which it provides sufficient amount of axial interfragmentary movement and considerable amount of cartilage production, while intramedullary nailing restricts axial movements but causes high magnitude of shear movements. However, nailing is superior to plating from the mechanical point of view and provides earlier weight bearing. In addition, it was shown that by using composite materials, biomechanical behavior of both fixation techniques will be improved through decreasing risk of failure and promoting cartilaginous tissue production.

Treatment of distal intraarticular tibial fractures: A biomechanical evaluation of intramedullary nailing vs. angle-stable plate osteosynthesis

In factures of the distal tibia with simple articular extension, the optimal surgical treatment remains debatable. In clinical practice, minimally invasive plate osteosynthesis and intramedullary nailing are both routinely performed. Comparative biomechanical studies of different types of osteosynthesis of intraarticular distal tibial fractures are missing due to the lack of an established model. The goal of this study was first to establish a biomechanical model and second to investigate, which are the biomechanical advantages of angle-stable plate osteosynthesis and intramedullary nailing of distal intraarticular tibial fractures. Seven 4(th) generation biomechanical composite tibiae featuring an AO 43-C2 type fracture were implanted with either osteosynthesis technique. After primary lag screw fixation, 4-hole Medial Distal Tibial Plate (MDTP) with triple proximal and quadruple distal screws or intramedullary nailing with double proximal and triple 4.0mm distal interlocking were implanted. The stiffness of the implant-bone constructs and interfragmentary movement were measured under non-destructive axial compression (350 and 600 N) and torsion (1.5 and 3Nm). Destructive axial compression testing was conducted with a maximal load of up to 1,200 N. No overall superior biomechanical results can be proclaimed for either implant type. Intramedullary nailing displays statistically superior results for axial loading in comparison to the MDTP. Torsional loading resulted in non-statistically significant differences for the two-implant types with higher stability in the MDTP group. From a biomechanical view, the load sharing intramedullary nail might be more forgiving and allow for earlier weight bearing in patients with limited compliance.

Evaluation of the effectiveness of the angular stable locking system in patients with distal tibial fractures treated with intramedullary nailing: a multicenter randomized controlled trial

BACKGROUND

Angular stable locking of intramedullary nails has been shown to enhance fixation stability of tibial fractures in biomechanical and animal studies. The aim of our study was to assess whether use of the angular stable locking system or conventional locking resulted in earlier full weight-bearing with minimum pain for patients with a distal tibial fracture treated with an intramedullary nail.

METHODS

A prospective multicenter, randomized, patient-blinded trial was conducted with adults who had a distal tibial fracture. Patients' fractures were managed with an intramedullary nail locked with either an angular stable locking system or conventional locking screws. Outcomes were evaluated at six weeks, twelve weeks, six months, and one year after surgery. Time to full weight-bearing with minimum pain was calculated with use of daily entries from patient diaries. Secondary outcomes included pain at the fracture site under load, quality of life, gait analysis, mobility, radiographic findings, and adverse events.

RESULTS

One hundred and forty-two patients were randomly allocated to two treatment groups: seventy-five to the group receiving intramedullary nailing with the angular stable locking system and sixty-seven to the group receiving conventional intramedullary nailing. No clinically important differences were found for either the primary or secondary outcome parameters between the groups during the entire follow-up period.

CONCLUSIONS

Use of an angular stable locking system with intramedullary nailing did not improve the outcome compared with conventional locking screws in the treatment of distal tibial fractures.

Controversies in the intramedullary nailing of proximal and distal tibia fractures

Management of tibia fractures by internal fixation, particularly intramedullary nails, has become the standard for diaphyseal fractures. However, for metaphyseal fractures or those at the metaphyseal-diaphyseal junction, choice of fixation device and technique is controversial. For distal tibia fractures, nailing and plating techniques may be used, the primary goal of each being to achieve acceptable alignment with minimal complications. Different techniques for reduction of these fractures are available and can be applied with either fixation device. Overall outcomes appear to be nearly equivalent, with minor differences in complications. Proximal tibia fractures can be fixed using nailing, which is associated with deformity of the proximal short segment. A newer technique-suprapatellar nailing-may minimize these problems, and use of this method has been increasing in trauma centers. However, most of the data are still largely based on case series.

Retrograde tibial nailing: a minimally invasive and biomechanically superior alternative to angle-stable plate osteosynthesis in distal tibia fractures

BACKGROUND

Currently, antegrade intramedullary nailing and minimally invasive plate osteosynthesis (MIPO) represent the main surgical alternatives in distal tibial fractures. However, neither choice is optimal for all bony and soft tissue injuries. The Retrograde Tibial Nail (RTN) is a small-caliber prototype implant, which is introduced through a 2-cm-long incision at the tip of the medial malleolus with stab incisions sufficient for interlocking. During this project, we investigated the feasibility of retrograde tibial nailing in a cadaver model and conducted biomechanical testing.

METHODS

Anatomical implantations of the RTN were carried out in AO/OTA 43 A1-3 fracture types in three cadaveric lower limbs. Biomechanical testing was conducted in an AO/OTA 43 A3 fracture model for extra-axial compression, torsion, and destructive extra-axial compression. Sixteen composite tibiae were used to compare the RTN against an angle-stable plate osteosynthesis (Medial Distal Tibial Plate, Synthes®). Statistical analysis was performed by Student's t test.

RESULTS

Retrograde intramedullary nailing is feasible in simple fracture types by closed manual reduction and percutaneous reduction forceps, while in highly comminuted fractures, the use of a large distractor can aid the reduction. Biomechanical testing shows a statistically superior stability (p < 0.001) of the RTN during non-destructive axial loading and torsion. Destructive extra-axial compression testing resulted in failure of all plate constructs, while all RTN specimens survived the maximal load of 1,200 N.

CONCLUSIONS

The prototype retrograde tibial nail meets the requirements of maximum soft tissue protection by a minimally invasive surgical approach with the ability of secure fracture fixation by multiple locking options. Retrograde tibial nailing with the RTN is a promising concept in the treatment of distal tibia fractures.

The influence of distal locking on the need for fibular plating in intramedullary nailing of distal metaphyseal tibiofibular fractures

Using human cadaver specimens, we investigated the role of supplementary fibular plating in the treatment of distal tibial fractures using an intramedullary nail. Fibular plating is thought to improve stability in these situations, but has been reported to have increased soft-tissue complications and to impair union of the fracture. We proposed that multidirectional locking screws provide adequate stability, making additional fibular plating unnecessary. A distal tibiofibular osteotomy model performed on matched fresh-frozen lower limb specimens was stabilised with reamed nails using conventional biplanar distal locking (CDL) or multidirectional distal locking (MDL) options with and without fibular plating. Rotational stiffness was assessed under a constant axial force of 150 N and a superimposed torque of ± 5 Nm. Total movement, and neutral zone and fracture gap movement were analysed.

In the CDL group, fibular plating improved stiffness at the tibial fracture site, albeit to a small degree (p = 0.013). In the MDL group additional fibular plating did not increase the stiffness. The MDL nail without fibular plating was significantly more stable than the CDL nail with an additional fibular plate (p = 0.008).

These findings suggest that additional fibular plating does not improve stability if a multidirectional distal locking intramedullary nail is used, and is therefore unnecessary if not needed to aid reduction.

Cite this article: Bone Joint J 2014;96-B:385–9.

The Retrograde Tibial Nail: presentation and biomechanical evaluation of a new concept in the treatment of distal tibia fractures

Displaced distal tibia fractures require stable fixation while minimizing secondary damage to the soft tissues by the surgical approach and implants. Antegrade intramedullary nailing has become an alternative to plate osteosynthesis for the treatment of distal metaphyseal fractures over the past two decades. While retrograde intramedullary nailing is a standard procedure in other long bone fractures, only few attempts have been made on retrograde nailing of tibial fractures. The main reasons are difficulties of finding an ideal entry portal and the lack of an ideal implant for retrograde insertion. The Retrograde Tibial Nail (RTN) is a prototype intramedullary implant developed by our group. The implant offers double proximal and triple distal interlocking with an end cap leading to an angle-stable screw-nail construct of the most distal interlocking screw. Its design meets the requirements of a minimally invasive surgical approach, with a stable fracture fixation by multiple locking options. The 8mm diameter curved nail, with a length of 120 mm, is introduced through an entry portal at the medial malleolus. We see possible indications for the RTN in far distal tibial shaft fractures, distal extraarticular metaphyseal tibial fractures and in distal tibia fractures with simple extension into the ankle joint when the nail is combined lag screw fixation. A biomechanical comparison of the current RTN prototype against antegrade nailing (Expert Tibial Nail, Synthes(®), ETN) was performed. Both implants were fixed with double proximal and triple distal interlocking. Seven biomechanical composite tibiae were treated with either osteosynthesis techniques. A 10mm defect osteotomy 40 mm proximal to the joint line served as an AO 43-A3 type distal tibial fracture model. The stiffness of the implant-bone constructs was measured under low and high extra-axial compression (350 and 600 N) and under torsional load (8 Nm). Results show a comparable stability during axial loading for the two implant types with slightly higher stability in the RTN group. Rotational stability was superior for the RTN. Statistical analysis proved a significant difference (p<0.05) between the ETN and RTN for rotational stability. This study suggests that retrograde tibia nailing with the RTN is a promising new concept for the treatment of distal tibia fractures.