Long-term stability of angle-stable versus conventional locked intramedullary nails in distal tibia fractures

Improved weight bearing during gait at 6 weeks post-surgery with an angle stable locking system after distal tibial fracture

BACKGROUND

Functional recovery after intramedullary nailing of distal tibial fractures can be monitored using ipsilateral vertical ground reaction forces (vGRF), giving insight into recovery of patients' gait symmetry. Previous work compared patient cohorts to healthy controls, but it remains unclear if these metrics can identify treatment-based differences in return to function post-surgery.

RESEARCH QUESTION

Is treatment of a distal tibial fracture with intramedullary nailing with an angle stable locking system (ASLS) associated with higher ipsilateral vGRF and improved symmetry compared to conventional intramedullary nailing at an early time point?

METHODS

Thirty-nine patients treated with ASLS intramedullary nailing were retrospectively compared to thirty-nine patients with conventional locking. vGRFs were collected at 1, 6, 12, 26, and 52 weeks post-surgery during standing and gait. Discrete metrics of ipsilateral vGRF (maximal force, impulse) and asymmetry were compared between treatments at each time point. Time-scale comparisons of ipsilateral vGRF and lower limb asymmetry were additionally performed for gait trials. Mann-Whitney Test or a two-way analysis of variance tested discrete comparisons; statistical non-parametric mapping tested time-scale data between treatment groups.

RESULTS

During gait, ASLS-treated patients applied more load on the operated limb (17-38% stance, p = 0.015) and consequently loaded limbs more symmetrically (8-37% stance, p = 0.008) during the loading response at 6 weeks post-surgery compared to conventional IM treatment. Discrete measures of symmetry at the same time point identified treatment-based differences in maximal force (p = 0.039) and impulse (p = 0.012), with ASLS-treated patients exhibiting more symmetry. No differences were identified in gait trials at later time points nor from all standing trials.

SIGNIFICANCE

During the initial loading response of gait, increased ipsilateral vGRF and improved weightbearing symmetry were identified in ASLS patients at 6 weeks post-surgery compared to conventional IM nailing. Early and objective metrics of dynamic movement are suggested to identify treatment-based differences in functional recovery.

Outcomes of Angular Stable Locking System in Femoral Diaphyseal Fractures of Elderly Patients: A Multicenter Comparative Study

Background

The angular stable locking system (ASLS) was developed to provide additional stability to the distal interlocking screw of the intramedullary (IM) nail. Effects of ASLS on the treatment of femoral diaphyseal fractures in the elderly remain unknown. The aim of this study was to compare radiological outcomes of IM nailing using ASLS screws to IM nails with conventional interlocking screws in elderly patients with femoral shaft fractures.

Methods

A multicenter retrospective review of 129 patients (average age, 73.5 years; 98 women and 31 men) aged 65 years or older who underwent IM nail fixation for femoral diaphyseal fractures (AO/Orthopaedic Trauma Association [OTA] classification 32) was conducted. Demographic information of patients, fracture site (subtrochanteric or shaft), fracture type (traumatic or atypical), and AO/OTA fracture classification were investigated. Reduction status was evaluated by postoperative plain radiography. Presence of union and time to union were evaluated through serial plain radiograph follow-up. Reoperation due to nonunion or implant failure was also evaluated.

Results

ASLS was used in 65 patients (50.3%). A total of 118 patients (91.5%) achieved union without additional surgery and the mean union time was 31.8 ± 13.0 weeks. In terms of reduction status, angulation was greater in the group using ASLS. There were no statistically significant differences of union rate, time to union, and reoperation rate according to the use of ASLS (p > 0.05). There was no difference in the outcomes according to the use of ASLS even when the analysis was divided in terms of fracture site or fracture type (p > 0.05). In further subgroup analysis, only the traumatic subtrochanteric area group showed statistically significantly shorter time to union when ASLS was used (p = 0.038).

Conclusions

In geriatric patients with femoral diaphyseal fractures, the use of ASLS was not considered to have a significant effect on fracture healing. Fracture healing seemed to be more affected by surgical techniques such as minimizing the gap and fracture characteristics such as atypical femoral fractures, rather than implants.

Angular stable locking in a novel intramedullary nail improves construct stability in a distal tibia fracture model

INTRODUCTION

Intramedullary nails are frequently used for treatment of unstable distal tibia fractures. However, insufficient fixation of the distal fragment could result in delayed healing, malunion or nonunion. Recently, a novel concept for angular stable nailing was developed that maintains the principle of relative stability and introduces improvements expected to reduce nail toggling, screw migration and secondary loss of reduction. The aim of this study was to investigate the biomechanical competence of the novel angular stable intramedullary nail concept for treatment of unstable distal tibia fractures, compared to a conventional nail locking in a human cadaveric model under dynamic loading.

MATERIALS AND METHODS

Ten pairs of fresh-frozen human cadaveric tibiae with a simulated AO/OTA 42-A3.1 fracture were assigned to 2 groups for reamed intramedullary nailing using either a conventional (non-angular stable) Expert Tibia Nail (ETN) with 3 distal screws or the novel Tibia Nail Advanced (TNA) system with 2 distal angular stable locking low-profile retaining screws. The specimens were biomechanically tested under conditions including initial quasi-static loading, followed by progressively increasing combined cyclic axial and torsional loading in internal rotation until failure of the bone-implant construct. Both tests were monitored by means of motion tracking.

RESULTS

Initial nail toggling of the distal tibia fragment in varus and flexion under axial loading was lower for TNA compared to ETN, being significant in flexion, P = 0.91 and P = 0.03. After 5000 cycles, interfragmentary movements in terms of varus, flexion, internal rotation, axial displacement, and shear displacement at the fracture site were all lower for TNA compared to ETN, with flexion and shear displacement being significant, P = 0.14, P = 0.04, P = 0.25, P = 0.11 and P = 0.04, respectively. Cycles to failure until both interfragmentary 5° varus and 5° flexion were significantly higher for TNA compared to ETN, P = 0.04.

CONCLUSION

From a biomechanical perspective, the novel angular stable intramedullary nail concept provides increased construct stability and maintains it over time while reducing the number of required locking screws without impeding the flexibility of the nail itself and resists better towards loss of reduction under dynamic loading, compared to conventional locking in intramedullary nailed unstable distal tibia fractures.

Can Preoperative 3D Printing Change Surgeon's Operative Plan for Distal Tibia Fracture?

This study aimed to determine if 3D printing can affect surgeon's selection of plate for distal tibia fracture surgery and to find out whether orthopedic surgeons consider this technology necessary and would use it in their practice. A total of 102 orthopedic surgeons were asked to choose anatomically contoured locking plates among 5 most commonly used types for one simple and one complex distal tibia fracture based on X-ray and CT images. Next, they were provided real-size 3D printed models of the same fractures, allowed to apply each of the 5 plates to these models, and asked if they would change their choice of plate. A 10-point numeric rating scale was provided to measure the extent of the help that 3D printing provided on preoperative planning. Finally, we asked the surgeons if they would use 3D printing in their practice. Seventy-four percent of inexperienced surgeons changed their selection of plate after using 3D printed models for the complex fracture. In contrast, only 9% of experienced surgeons changed their selection of plate for the simple fracture. Surgeons rated the extent of usefulness of the 3D models in preoperative planning as a mean of 4.84 ± 2.54 points for the simple fracture and 6.63 ± 2.54 points for the complex fracture. The difference was significant (p < 0.001). Eighty-six percent of inexperienced surgeons wanted to use 3D models for complex fractures. However, only 18% of experienced surgeons wanted to use 3D printed models for simple fractures. The use of a real-size 3D-printed model often changed surgeon's preoperative selection of locking plates, especially when inexperienced surgeons evaluated a complex fracture. However, experienced surgeons did not find 3D models very useful when assessing simple fractures. Future applications of 3D models should focus on training beginners in fracture surgery, especially when complex fractures are concerned.

The Role of Biplanar Distal Locking in Intramedullary Nailing of Tibial Shaft Fractures

BACKGROUND

To compare the union times of the uncomplicated tibial shaft fractures, which were distally locked by two coronal and one sagittal screws and by only two coronal screws.

METHODS

45 patients with tibial shaft treated with intramedullary nailing included in this study. 23 of 45 fractures were treated with uniplanar two distal interlocking (Group 1) and 22 fractures were treated with biplanar three distal interlocking (Group 2). Patients with closed fractures treated by closed nailing and having a full set of radiographs on PACS system was included. Fracture unions were evaluated by two authors.

RESULTS

Union time was significantly shorter in biplanar distal interlocking group (Group 2) compared to uniplanar distal interlocking group (Group 1) (P=0.02). Mean union time in groups 1 and 2 were 14.63±4.5 and 10.77±3.0 weeks, respectively .When only distal third tibial shaft fractures were evaluated, Group 2 [11.2±3.1 weeks (n:17)] had significantly lower union time compared to Group 1 [15.07±4.8 weeks (n:14)] (P=0.01). Inter-observer reliability for fracture union times was high with rho= 0.89 with SE of 0.51 (P<0.001).

CONCLUSION

Biplanar distal interlocking procedure had a significantly shorter union time. Biplanar distal interlocking procedure allows a faster fracture union probably because of a more stable fixation construct.

Clinical Management of Osteoporotic Fractures

PURPOSE OF REVIEW

This review examines recent literature regarding the clinical management of fragility fractures, provides insight into new practice patterns, and discusses controversies in current management.

RECENT FINDINGS

There are declining rates of osteoporosis management following initial fragility fracture. Management of osteoporotic fractures via a multidisciplinary team reduces secondary fracture incidence and improves overall osteoporotic care. Anabolic agents (abaloparatide and teriparatide) are effective adjuvants to fracture repair, and have shown positive results in cases of re-fracture in spite of medical management (i.e., bisphosphonates). For AO 31-A1 and A2 intertrochanteric hip fractures (non-reverse obliquity), no clinical advantage of intramedullary fixation over the sliding hip screw (SHS) has been proven; SHS is more cost-effective. As fragility fracture incidence continues to rise, orthopedic surgeons must play a more central role in the care of osteoporotic patients. Initiation of pharmacologic intervention is key to preventing subsequent fragility fractures, and may play a supportive role in initial fracture healing. While the media bombards patients with complications of medical therapy (atypical femur fractures, osteonecrosis of jaw, myocardial infarction), providers need to understand and communicate the low incidence of these complications compared with consequences of not initiating medical therapy.

Comparison of Tibial Intramedullary Nailing Guided by Digital Technology Versus Conventional Method: A Prospective Study

Background

This prospective study aimed to compare clinical effects of intramedullary nailing guided by digital and conventional technologies in treatment of tibial fractures.

Material/Methods

Thirty-two patients (mean age 43 years, 18 males and 14 females) who were treated for tibial fractures from October 2010 to October 2012 were enrolled. They were sequentially randomized to receive intramedullary nailing guided by either digital technology (digital group, n=16) or conventional technology (conventional group, n=16). The operation time, fluoroscopy times, fracture healing time, distance between the actual and planned insertion point, postoperative lower limb alignment, and functional recovery were recorded for all patients.

Results

The mean operation time in the digital group was 43.1±6.2 min compared with 48.7±8.3 min for the conventional technology (P=0.039). The fluoroscopy times and distance between the actual and planned insertion point were significantly lower in the digital group than in the conventional group (both P<0.001). The accuracy rate of the insertion point was 99.12% by digital technology. No difference was found in fracture healing time and good postoperative lower limb alignment between the digital and conventional groups (P=0.083 and P=0.310), as well as the effective rate (100% vs. 87.50%, P=0.144).

Conclusions

Intramedullary nailing guided by digital technology has many advantages in treatment of tibial fractures compared to conventional technology, including shorter operation time, reduced fluoroscopy times, and decreased distance between the actual and planned insertion point of the intramedullary nail.

Intramedullary tibial nailing of distal tibiofibular fractures: additional fibular fixation or not?

INTRODUCTION

The anatomy of the distal tibia accounts for reduced biomechanical stability and higher complication rates when treating distal tibiofibular fractures with an intramedullary tibia nail (IMTN). The goal of this study was to identify variables that affect the stability of IMTN. We assessed the value of additional fibular fixation, angular stable interlocking screws (ASLS) and multiplanar screw configuration in IMTN.

PATIENTS AND METHODS

A retrospective cohort study was performed including 184 distal tibial fractures and associated fibula fracture treated with IMTN. Relevant demographic, fracture-related (type and level of the tibia and fibula fracture) and operative variables (depth of the nail, screw type and configuration, use of polar screws, fibular fixation) were studied. Coronal and sagittal alignment was assessed directly and 3-6 months after IMTN. Loss of reduction (LOR) was classified as 5-9° or ≥10°.

RESULTS

48.4% of the patients showed ≥5° LOR in one or both planes. Coronal LOR 5°-9° significantly correlated with low tibial fractures (p = 0.034), AO/OTA type 43 distal tibial fractures (p = 0.049), and sagittal LOR 5°-9° (p = 0.015). Although sagittal LOR 5°-9° was associated with fibular fractures (non-fixated suprasyndesmotic, p = 0.011), conversely we could not demonstrate the added value of (suprasyndesmotic) fibula fixation in IMTN. Coronal LOR ≥10° significantly correlated with AO/OTA type 43 distal tibial fractures (p = 0.009). In contrast to multiplanar configuration, we found a clear benefit of ASLS in distal IMTN locking.

CONCLUSIONS

The level of the tibial fracture (AO/OTA type) and (suprasyndesmotic) fibular fractures were the main determinants of LOR after IMTN. ASLS was found to increase the stability of IMTN. Due to heterogeneity, however, we could not demonstrate the value of fibular fixation in IMTN. Therefore, a future prospective study with uniform treatment strategy for IMTN of distal tibiofibular fractures, with or without fixation of the fibula, is mandatory.

Complications of intramedullary nailing-Evolution of treatment

Intramedullary nailing of diaphyseal long bone fractures is a standard procedure in today's trauma and orthopedic surgery due to the numerous advantages (e.g. minimal invasive, limited soft tissue damage, load stability). In the last decade indications have been extended to the metaphyseal region. This was associated with problems and complications due to the reduced bone-implant interface. The changed anatomical conditions lead to decreased implant anchorage. Newly developed locking solutions overcome most of these problems. First, the number and also the orientation of the locking screws were adapted to allow a multiplanar locking. This results in increased implant anchorage in the soft metaphyseal bone, thus construct stability significantly improved. Additional options like angular stable locking have been introduced and furthermore enhanced construct stability especially in poor bone stock. As a perspective locking screw augmentation shows promising results in first biomechanical testing.

Comparison of closed reduction and expert tibial nailing with open reduction and plate and screw fixation in the treatment of two segmental tibial fractures

PURPOSE

To compare the outcomes of closed reduction and expert tibial nailing (ETN) versus open reduction and plate and screw fixation in treating two segmental tibial fractures.

METHODS

This study included 53 cases of two segmental fractures of the tibial shaft. They were admitted to our department between March 2010 and June 2013 and treated respectively by closed reduction and ETN (ETN group, n=31) or open reduction fixation with plate and screws (PS group, n=22). The general data of two groups including gender, age, injury cause, fracture type, etc showed no significant difference (p>0.05). To compare the therapeutic effects between two groups, the intraoperative condition, post- operative function and related complications were investigated.

RESULTS

All the patients were successfully followed up. The period was 19.2 months for ETN group and 20.5 months for PS group. All the fractures in ETN group had union without complications such as malunion, infection, or osteofascial compartment syndrome; whereas there were 3 cases of superficial infection cured by repeated dressing change and 2 cases of delayed union in PS group. The total incidence of complication in PS group was 22.7% (5/22), much higher than that in ETN group (p<0.05). Moreover, ETN group showed a better result in terms of intraoperative blood loss, operation time, postoperative weight bearing time and fracture union time. In ETN group, at one-year follow-up, Johner-Wruhs' criteria was adopted to assess the postoperative function, which was reported as excellent in 18 cases, good in 10 cases and fair in 3 cases in ETN group (100% excellent-good rate). While in PS group, the result was excellent in 10 cases, good in 7 cases, fair in 3 cases and poor in 2 cases (77.3% excellent-good rate). The comparison was insignificant (p>0.05).

CONCLUSION

Compared with plate and screw fixation, ETN fixation has the advantages of fewer complications, shorter operation time, being less invasive, earlier postoperative rehabilitation and weight bearing, quicker fracture union and better functional recovery, thus being an effective way to treat two segmental tibial fractures.

Distal Locking Screws for Intramedullary Nailing of Tibial Fractures

Recently introduced tibial intramedullary nails allow a number of distal screws to be used to reduce the incidence of malalignment and loss of fixation of distal metaphyseal fractures. However, the number of screws and the type of screw configuration to be used remains obscure. This biomechanical study was performed to address this question. Thirty-six Expert tibial nails (Synthes, Oberdorf, Switzerland) were introduced in composite bone models. The models were divided into 4 groups with different distal locking configurations ranging from 2 to 4 screws. A 7-mm gap osteotomy was performed 72 mm from the tibial plafond to simulate a 42-C3 unstable distal tibial fracture. Each group was divided in 3 subgroups and underwent nondestructive biomechanical testing in axial compression, coronal bending, and axial torsion. The passive construct stiffness was measured and statistically analyzed with one-way analysis of variance. Although some differences were noted between the stiffness of each group, these were not statistically significant in compression (P=.105), bending (P=.801), external rotation (P=.246), and internal rotation (P=.370). This in vitro study showed that, when using the Expert tibial nail for unstable distal tibial fractures, the classic configuration of 2 parallel distal screws could provide the necessary stability under partial weight-bearing conditions.

A modified and enhanced test setup for biomechanical investigations of the hindfoot, for example in tibiotalocalcaneal arthrodesis

Background

Tibiotalocalcaneal arthrodesis (TTCA) using intramedullary nails is a salvage procedure for many diseases in the ankle and subtalar joint. Despite “newly described intramedullary nails” with specific anatomical shapes there still remain major complications regarding this procedure. The following study presents a modified biomechanical test setup for investigations of the hindfoot.

Methods

Nine fresh-frozen specimens from below the human knee were anaysed using the Hindfoot Arthrodesis Nail (Synthes) instrument. Quasi-static biomechanical testing was performed for internal/external rotation, varus/valgus and dorsal/plantar flexion using a modified established setup (physiological load entrance point, sledge at lever arm to apply pure moments). Additionally, a 3D optical measurement system was added to allow determination of interbony movements.

Results

The mean torsional range of motion (ROM) calculated from the actuator data of a material testing machine was 10.12° (SD 0.6) compared to 10° (SD 2.83) as measured with the Optotrak® system (between tibia and calcaneus). The Optotrak showed 40 % more rotation in the talocrural joint.

Mean varus/valgus ROM from the material testing flexion machine was seen to be 5.65° (SD 1.84) in comparison to 2.82° (SD 0.46) measured with the Optotrak. The subtalar joint showed a 70 % higher movement when compared to the talocrural joint.

Mean ROM in the flexion test was 5.3° (SD 1.45) for the material testing machine and 2.1° (SD 0.39) for the Optotrak. The movement in the talocrural joint was 3 times higher compared to the subtalar joint.

Conclusion

The modified test setup presented here for the hindfoot allows a physiological biomechanical loading. Moreover, a detailed characterisation of the bone-implant constructs is possible.

A novel nail providing more biomechanical rotational and axial stability than conventional interlocking nail in femur complex fracture model

PURPOSE

Inter-fragmentary rotational and axial instabilities are major challenges in nailing of complex or comminuted fractures. We aimed to compare the inter-fragmentary rotational and axial stability of novel anti-rotation interlocking nail and the conventional interlocking nail in complex or comminuted femur shaft fractures.

METHODS

Twenty composite femurs were divided into two groups, 30 mm was resected from the mid-portion of all composite femurs. The inter-fragmentary rotational and axial stabilities were assessed.

RESULTS

Between 10-N m external and 6-N m internal rotation torques, mean maximum inter-fragmentary rotational arc motion in the novel nails was 1.63 mm and 291 % less than that of the conventional nails (6.38 mm, P = 0.000). Between 150 N distraction and 2300 N compression, mean axial motion in the novel nails was 0.8 mm and 257 % less than that of the conventional nails (2.86 mm, p = 0.000).

CONCLUSION

An anti-rotational novel nail is superior to the conventional interlocking nail in terms of maximum inter-fragmentary rotational and axial stabilities in complex and comminuted femur shaft fractures.

[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.

Intramedullary nailing of humeral shaft fractures: failure analysis of a single centre series

INTRODUCTION

Intramedullary nailing (IMN) is an accepted technique for the treatment of humeral shaft fractures. Previous studies published concerns over whether this technique had higher complication rates such as nonunion and technical failures compared to plate osteosynthesis. We, therefore, conducted a single centre failure analysis to critically evaluate our results regarding IMN of humeral shaft fractures.

MATERIALS AND METHODS

Between January 2000 and January 2013, 246 consecutive patients with humeral shaft fractures were enrolled. Inclusion criteria were skeletal maturity and humeral shaft fractures treated with IMN. Exclusion criteria were skeletal immaturity, primary treatment by plate osteosynthesis, primary treatment outside the University Hospitals Leuven, presence of metaphyseal fractures and the presence of pathological fractures. Negative outcome measures such as infection, nonunion and early technical failure were retrospectively assessed.

RESULTS

During the study period, 149 patients with 149 fractures met the inclusion criteria. Of these, 14 patients were lost to follow-up, two died from trauma-related causes within the first 30 days after the accident, and eight died from other causes (cardiovascular disease and cancer) leaving 125 patients with 125 fractures for a minimum follow-up period of 12 months. Failure analysis showed that six (4.8 %) patients developed a nonunion. One (0.8 %) patient was diagnosed with a deep infection. In total, five (5 %) patients underwent surgical revision due to early technical failures.

CONCLUSIONS

IMN is a valid therapeutic option for humeral shaft fractures. Good surgical technique and soft tissue handling are important for good outcome. Currently, patient demands are receiving greater consideration. In an era where early full range of motion and rapid return to work with minimal scarring is mandatory for most patients, the use of IMN will most likely increase in popularity in the future.

Results of angular-stable locked intramedullary nails in the treatment of distal tibia fractures

INTRODUCTION

Intramedullary nailing in distal tibial fracture is controversial because of a lack of stability. The present study sought to assess radiological and clinical results for a new "angular-stable" locking system in difficult indications for intramedullary nailing.

MATERIAL AND METHOD

A prospective study recruited 41 patients (41 tibias) with distal tibial fracture consecutively managed using angular-stable locked intramedullary nails. Radiologic assessment comprised AP and lateral lower-limb views, taken postoperatively and through to last follow-up. The mean distance was measured between fracture and joint line. Fusion, with or without malunion, primary reduction defect, non-union and secondary displacement were recorded, as were all complications.

RESULTS

Mean follow-up was 18 ± 5 months; 3 patients were lost to follow-up. Mean fracture distance from the joint line was 63 ± 25 mm. Fusion was achieved within 3 months in 29 cases (76%); delayed fusion in 7 patients (18%) required secondary dynamization at a mean 3 months, with favorable evolution. Revision surgery was required in 2 cases: 1 for secondary displacement exceeding 10°, and 1 for non-union at 7 months. Other complications mainly comprised 4 malunions of less than 10° due to primary reduction defect.

CONCLUSION

Angular-stable locked lower-limb intramedullary nailing provided a very satisfactory fusion rate, with few complications. It is, however, a demanding procedure, especially as regards fracture reduction and nail positioning in the distal fragment.

PROSPECTIVE COHORT STUDY

level IV.

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.

Disadvantages of interfragmentary shear on fracture healing--mechanical insights through numerical simulation

The outcome of secondary fracture healing processes is strongly influenced by interfragmentary motion. Shear movement is assumed to be more disadvantageous than axial movement, however, experimental results are contradictory. Numerical fracture healing models allow simulation of the fracture healing process with variation of single input parameters and under comparable, normalized mechanical conditions. Thus, a comparison of the influence of different loading directions on the healing process is possible. In this study we simulated fracture healing under several axial compressive, and translational and torsional shear movement scenarios, and compared their respective healing times. Therefore, we used a calibrated numerical model for fracture healing in sheep. Numerous variations of movement amplitudes and musculoskeletal loads were simulated for the three loading directions. Our results show that isolated axial compression was more beneficial for the fracture healing success than both isolated shearing conditions for load and displacement magnitudes which were identical as well as physiological different, and even for strain-based normalized comparable conditions. Additionally, torsional shear movements had less impeding effects than translational shear movements. Therefore, our findings suggest that osteosynthesis implants can be optimized, in particular, to limit translational interfragmentary shear under musculoskeletal loading.

A tip to reduce the malrotation of the spiral tibial fracture intraoperatively

BACKGROUND

Tibial spiral fractures treated by closed intramedullary (IM) nailing are at risk for malrotational deformities. The purpose of this study was to examine a method to minimize the risk of tibial malrotation during closed IM nailing of spiral tibial fractures.

METHODS

This trial is done through 24 patients of spiral tibial fractures with a mean age of 38.5 years (range 26-63 years). The patients were divided into two groups. One group the fractures were reduced by rotating the distal locked nail to obtain rotational alignment and another group by the standard assistant rotated technique. All the patients were evaluated with CT scans postoperatively. The parameters such as rotational values, operative and radiation exposure time were recorded and compared between two groups. Mann-Whitney test was used to test the significance of these parameters.

RESULTS

The group using the tip had a smaller mean rotational value, which was (6.8° ± 2.1° vs. 11.8° ± 5.2°; P < 0.01). The mean operative time was not statistically different (70.6 ± 4.4 vs. 63.0 ± 2.9 min; P > 0.05), so did the mean radiation exposure time (48.1 ± 4.2 vs. 42.6 ± 4.8 s; P > 0.05).

CONCLUSION

The described technique of rotating the nail after initial distal interlocking can correct rotational abnormalities in spiral tibial shaft fractures in the premise of not increasing the operative and radiation exposure times statistically.

A new angle stable nailing concept for the treatment of distal tibia fractures

PURPOSE

Surgical treatment of distal tibial fractures demands a stable fracture fixation while minimizing the irritation to the soft tissues by approach and implant. Biomechanical studies have demonstrated superior performance for angular-stable locked nails over standard locked nails in distal tibial fractures. The experimental Retrograde Tibial Nail (RTN) is a minimally invasive local intramedullary osteosynthesis, which has been under design by our group. We conducted a biomechanical comparison in composite tibiae of the Retrograde Tibial Nail against the Expert Tibial Nail (Synthes®). Our hypothesis was that the RTN would provide equivalent biomechanical stability with respect to extra-axial compression, torsion and load to failure testing, in an extra-articular distal tibia fracture model.

METHODS

Biomechanical composite bone testing was conducted in 14 biomechanical composite tibiae in an AO 43 A3 fracture model. In both groups, triple angle stable interlocking was performed in the distal fragment.

RESULTS

Results show a statistically non-significant higher stability of the ETN during the axial loading tests. Torsional stability testing resulted in a statistically superior performance for the RTN (p = 0.018). Destructive extra-axial compression resulted in failure of six ETN constructs, while all RTN specimens survived the maximal load.

CONCLUSIONS

The experimental Retrograde Tibial Nail provides the key features for the treatment of distal tibial fractures. It combines a minimally invasive local intramedullary osteosynthesis with the ability to securely fix the fracture by multiple angle stable locking options.

A method to modify angle-stable intramedullary nail construct compliance

Traditional interlocked intramedullary (IM) nails have recently been modified to provide enhanced angular stability. These so-called 'angle-stable' IM nails are designed to eliminate construct toggle and also provide increased axial, bending, and torsional stiffness. While this added stability is needed for small fracture gaps to heal, angle-stable nails may be too stiff for large fracture gaps to unite. Even though relative stability is recommended for large fracture gaps, recent in vivo data indicates that traditional nails may allow for too much motion for healing to occur. The current study evaluated a modified technique for implanting an angle-stable nail which allows for an intermediate amount of stability. The compliance of the nail construct was adjusted by over-drilling the near cortex interlocking hole. This led to increased construct motion in torsion, but less so in axial compression and bending. This modification creates stability which is partway between angle-stable and traditional IM nail designs. These findings were unchanged after 50,000 fatigue loading cycles. By carefully selecting the magnitude of over-drilling, the compliance of the construct can easily be modified as it is being implanted. This design modification may lead to more reliable fracture union since the surgeon can tailor the nail compliance to the injury and bone quality.