Static Intramedullary Nailing Research Articles

Functional Outcome of Closed Static Intramedullary Nailing with Distal two Plane Locking Versus Percutaneous Mippo Distal Tibial Locking Plate in Distal 3rd Tibia Metaphyseal Fractures

Objective: Aim of current study was to determine the functional outcomes of closed static intramedullary nailing with distal two plane locking versus percutaneous MIPPO distal tibial locking plate in distal 3rd tibia metaphyseal fractures. Study Design: Randomized clinical trial Place and Duration: Nishtar Hospital Multan/Qaisrani Medical Center Multan. Jan 2021-March 2022 Methods: There were 76 patients of both genders with age 15-60 years presented. All the patients had 3rd tibia metaphyseal fracture were admitted to hospital for surgery. Following the collection of informed written consent from enrolled patients, complete demographic information was gathered. Patients were equally divided into two groups. Group I received intramedullary nailing with distal two plane locking and group II received percutaneous MIPPO distal locking plate. Favorable and unfavorable outcomes among enrolled cases were compared. SPSS 22.0 was used to analyze all data. Results: There were majority males 22 (60.5%) in group I and 20 (52.6%) in group II. In group I mean age was 30.8±6.42 years with mean BMI 24.71±3.19 kg/m2 and in group II mean age was 31.14±3.58 years and had mean BMI 25.7±7.17 kg/m2. Falling, accidents, sports and lifting of heavy object was the most common cause of fractures. We found that intramedullary nailing was more effective as compared to MIPPO distal locking plate in terms of functional outcomes but difference was insignificant. Frequency of complications were higher in group II found in 14 (36.8%) as compared to group I in 4 (10.4%) cases. Conclusion: We concluded in this study that distal third tibial metaphyseal fractures were effectively operated by intramedullary nailing distal two plane locking and MIPPO distal locking plate but frequency of complications were higher in MIPPO group as compared to intramedullary nailing. Keywords: Metaphyseal Fractures, MIPPO Distal Platting, Intramedullary Nailling, Functional Outcomes, Complications

Various modalities of management of segmental fractures of long bones

Introduction: Segmental long bone fractures in high energy injuries are a challenging combination of bone and soft-tissue damage and loss. The state of the surrounding soft tissues and the local blood supply to the bone are the most important factors determining the tendency of the fracture to heal. Objectives: To study the efficacy and safety of various method of treatment in segmental fractures long bones and various complications associated with it. Materials and Methods: 20 patients with segmental fractures of long bones, satisfying the inclusion criteria, who were treated with various modalities of management were included in the study.The fractures were evaluated clinically as well as radiologically and the modality of management was based on the type of fracture and associated injuries. Out of 10 tibial fractures, 6 were treated with static intramedullary nail, and 2 with external fixator 2 conservatively. Out of 5 femoral fractures,4 were treated with intramedullary nail. Out of 2 humerus fractures 2 were treated with dynamic compression plate technique. Out of 3 both bone forearm fractures 3 were treated with dynamic compression plate technique.

Acute correction and intramedullary nailing of aseptic oligotrophic and atrophic tibial nonunions with deformity.

Objectives This study aims to describe the important points for treatment of aseptic tibial oligotrophic and atrophic nonunions by intramedullary nailing (IMN).Patients and methods The retrospective study included 17 biologically nonactive nonunion patients (12 males, 5 females; mean age 36.4 years; range, 19 to 49 years) operated between February 2010 and November 2017 by deformity correction, static IMN and autografting. The mean follow-up time was 4.2 (range, 3 to 7) years. The initial fracture management was external fixator for all patients. Fourteen patients had open fractures initially. Six patients had valgus, four patients had varus, three patients had oblique plane, and four patients had external rotational deformity. Nonunion diagnosis was established on the basis of the patient history and physical examination based on plain radiographs, computed tomography or both. All patients were evaluated by the same protocol to exclude any infection.Results The median time from injury to nailing was mean 10.3 (range, 6.1 to 36.5) months. Radiologic and clinical union was achieved in all patients. The mean union time was 3.64 (range, 3 to 6) months. Three patients had positive intraoperative bacteriological culture. In four patients, dynamization was necessary for consolidation. Late deep infection developed in three patients after union, and all infected cases were operated by implant removal, debridement, and appropriate antibiotics.ConclusionIntramedullary nailing and autografting after external fixator provide good results for the treatment of aseptic biologically nonactive nonunions with deformity. Reamed IMN ensures sufficient deformity correction, biological environment, and mechanical stability. The infection risk should always be kept in mind and patients should be followed-up closely to prevent complications.

Role of fibular fixation in static intramedullary interlocking nailing for distal third tibia and fibula fracture

Treatment of distal third tibia and fibula fractures remains a challenge classically being treated with standard plating, but intramedullary nailing has gained popularity. As there is a mismatch between the diameters of the nail and the medullary canal, with no nail-cortex contact, the nail may translate laterally along coronally placed locking screws and increased stress in placed on the locking holes to maintain fracture alignment after surgery. Various techniques have been recommended to improve nailing in these fractures including fibular plating (distal third fractures), temporary unicortical plating, different nail design with different proximal bends (proximal third fractures) and blocking screws (poller screws). The aim of the study is to evaluate the clinical use of fibular plating as a supplement to stability in addition to intramedullary nailing in distal both bone fractures of leg. Methods: A prospective study of 20 cases of distal third tibia fibula fractures treated with statically locked intra medullary nailing with supplementary fibular plating between March 2017 and September 2018 at RIMS, Ranchi. All the fractures were followed through till union of fracture with clinical and radiological examination at intervals of 4 to 6 weeks. On follow up axial alignment was assessed and functional analysis was quantified using Karlstorm – Olerud score. Complications were divided into those which were related to fibular plate and those which were not. Results: All the fractures eventually united in a mean period of 12.8 weeks. Karlstrom-Olerud score was excellent in 12 fractures (60%), good in 5 patients (25%) and fair in 2 patients (10%) and poor in 1 patient (5%).The alignment was maintained in coronal plane till union with the mean remaining the same i.e 1.6 degrees. The mean sagital plane alignment at the time of union was 0.4 degrees, the loss of alignment was not statistically significant. The fibular plate related complications were encountered in two cases where we had skin necrosis and deep infection, which needed aggressive antibiotic therapy and those patients were also given cast support for twelve weeks. Conclusion: Fibular plating, when supplemented the intramedullary nailing of distal third tibia fibula fractures, were effective in achieving the fracture alignment especially in fresh fractures, Improves not only angular stability but also rotational stability, Maintained the fracture alignment till union and prevents loss of initial reduction.

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

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

A new intramedullary sustained dynamic compression nail for the treatment of long bone fractures: a biomechanical study.

We developed a new intramedullary interlocking nail (sustained dynamic compressive nail; SDCN) which can sustain a continuous dynamic compressive force on the fracture edges to overcome implant failure, screw loosening and nonunion complications encountered in the traditionally used static intramedullary nailing (SIMN). Six pairs of composite femurs were fixed with SIMN and SDCN. The axial compression, bending, torsional stiffness, and strain values were analyzed. The mean axial compression stiffness values were 427.1 N/mm for the SDCN and 217.8 N/mm for SIMN, indicating a statistically significant difference (p=0.006). The mean stiffness values of rotation were 1.42 Nm/° for the SDCN and 0.89 Nm/° for SIMN. Anteroposterior bending tests were carried out. The mean results of stiffness were measured as 218 N/mm for the SDCN and 182.7 N/mm for the SIMN. The mean strain measurements in compression were 2454.5 µ-strain for the SDCN and 1123.8 µ-strain for the SIMN. Biomechanically, the intramedullary SDCN is more stable than the SIMN system and it provides good abutment of the nail to the bone. Also, SDCN increases the stability by producing continuous compression and increasing the contact pressure of the fracture ends.

Static or Dynamic Intramedullary Nailing of Femur and Tibia

Introduction:The basic principle of non-surgical fracture treatment is to restore the original anatomical position of fractured fragments by different techniques, without direct access to the bone and without further traumatizing of tissues. Intramedullary nailing is synthesis and consolidation of fracture fragments with the main goal to gain strength and permanent placement of the implants. Two techniques of intramedullary osteosynthesis are used: with dynamic or with static intramedullary nail. Dynamization include conversion of static nail by removing screws from the longest fragment.Aim:The aim of this study is to determine whether there is a difference in the speed and quality of healing of the type A and B fractures of the femur and tibia treated by static or dynamic intramedullary nails and to compare the results.Material and methods:The study was conducted at the Clinic for Orthopaedics and Traumatology, Clinical Center University Sarajevo from January 2004 to June 2009. The study was retrospective-prospective, manipulative, controlled and it was conducted on a total of 129 patients with closed fractures of the diaphysis of the femur and tibia type A and type B, with different segments of bone, regardless of sex and age structure, with the exception of children under 14 years of age.Results:Precisely there were 47 patients with femoral fractures and 82 patients with tibial fractures. The average number of weeks of healing femoral and tibial fractures was slightly in advantage of static intramedullary osteosynthesis, it was 17.08 weeks (SD=3.382). The average number of weeks of healing in 23 patients with fractures of the femur, treated by dynamic intramedullary osteosynthesis was 17.83 (SD=2.978). We can conclude that static intramedullary nailing osteosynthesis unable movements between fragments which directly stimulates bone formation and formation of minimal callus.Conclusion:Static intramedullary osteosynthesis resolve the problem of stabilizing the fracture, limb shortening and rotation of fragments.

The Results of Closed Intramedullary Nailing for Intra-articular Distal Tibial Fractures

To evaluate the long-term radiological, clinical, and functional result of the intramedullary nailing in intra-articular distal tibia fractures. Retrospective clinical study. Level II Trauma Hospital. Between December 2000 and December 2006, 185 consecutive intra-articular distal tibia fractures were admitted in our institution. Fifty fractures were included in the study. According to the OTA classification, there were 28 (56%) fractures type 43 C1 and 22 (44%) type 43 C2. All fractures were treated with closed static intramedullary nailing with distal locking. In 37 (74%) patients, reduction of the articular extension of the fracture with additional internal fixation preceded the nailing. Fibula fixation was applied in 32 (64%) fractures. Routine dynamization of the fixation was performed in all cases at a mean time of 10 weeks postoperatively. The mean follow-up was 42 months (range: 36-54 months). Leg length, tibia alignment, articular reduction, and ankle arthrosis were assessed radiographically. The clinical outcome was assessed using the Olerud-Molander score. The functional limitation was assessed using the musculoskeletal functional assessment. All fractures healed at an average of 16.3 weeks (range: 14-28 weeks). Anatomic reduction of the articular surface was obtained in all fractures. The average coronal plane deformity was 0.74 degree (range: 0-4 degrees) and the average sagittal plane deformity was 0.62 degree (range, 0-4 degrees). The mean Olerud-Molander score was 92.8/100 (range: 80-100). The average short musculoskeletal function assessment score was 34.55 ± 31.88 (range: 0.8-96). Intramedullary nailing augmented with minimal internal fixation is a safe alternative for the treatment of distal tibial fractures with a simple articular extension. Because all objectives of the treatment were obtained, the results did not deteriorate over time. Therapeutic level IV. See instructions for authors for a complete description of levels of evidence.

Evaluation of static locked intramedullary nailing for treatment of comminuted femoral shaft fractures

BackgroundThe treatment of femoral shaft fractures has always been a focus of interest, but until now has remained a clinical problem and a subject of controversy. The aim of this work was to evaluate the role of static interlocked nailing in the treatment of a comminuted fracture of the femoral shaft in our initial cases managed by this technique at Al-Azhar University Hospitals.Patients and methodsThe results of treatment of comminuted fractures of the femoral shaft with static interlocking nailing were reviewed retrospectively in 60 patients. Ten of them had bilateral fractures, which allowed 70 fractures to be reviewed.ResultsAll managed fractures (100%) had healed without conversion to dynamic intramedullary fixation. No broken nails were detected. At the final postoperative follow-up evaluation according to Thoresen and colleagues, we obtained excellent and good results in 65 (92.85%) femoral fractures, fair results in five (7.15%) femoral fractures, and no (0%) poor result. We had 100% fracture union in all cases with a mean time of eight postoperative months.ComplicationsOnly one (1.4%) patient had deep infection. Eight (11.4%) patients had pulmonary embolism, which was the major cause of morbidity associated with bed recumbence in our study.ConclusionWe concluded that this method of treatment - static intramedullary nailing fixation - for comminuted shaft fractures of the femur is an effective method that maintains the length and alignment, with a low incidence of complications.

Fractures of the tibia shaft treated with locked intramedullary nail

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

A comparison of effi cacy of femoral and tibial fractures healing treated by static and dynamic intramedullary nails

Introduction: Intramedullary nailing is synthesis and consolidation of fracture fragments with the main goalto gain strength and permanent placement of the implants. Two techniques of intramedullary osteosynthesis are used: with dynamic or with static intramedullary nail. Dynamization include conversion of static nail by removing screws from the longest fragment. The aim of this study is to determine whether there is a difference in the speed and quality of healing of the type A and B fractures of the femur and tibia treated by static or dynamic intramedullary nails and to compare the results.Methods: The study was conducted on a total of 129 patients with closed fractures of the diaphysis of the femur and tibia type A and type B. Patients were divided into two groups, based on the applied operating method, static or dynamic intramedullary osteosynthesis.Results: The average number of weeks of healing femoral and tibial fractures was slightly in advantage of static intramedullary osteosynthesis, it was 17.08 weeks (SD=3.382). The average number of weeks of healing in 23 patients with fractures of the femur, treated by dynamic intramedullary osteosynthesis was 17.83 (SD=2.978).Conclusion: We can conclude that static intramedullary nailing osteosynthesis unable movements between fragments which directly stimulates bone formation and formation of minimal callus. Static intramedullary ostesinthesys resolve the problem of stabilizing the fracture, limb shortening and rotation of fragments.

Surgical Technique: Static Intramedullary Nailing of the Femur and Tibia Without Intraoperative Fluoroscopy

On a recent mission directed at definitive care for victims of the Haitian earthquake, the orthopaedic team developed a technique for freehand distal locking of femoral and tibial nails without intraoperative fluoroscopy or proximally mounted targeting jigs. After performing open antegrade or retrograde nailing by standard techniques, the freehand lock must be obtained before doing standard outrigger locking. This allows the surgeon to control the nail and deliver the locking hole in the nail to a unicortical drill hole in the femur. Before nail insertion, the distance of the desired locking hole is measured from the outrigger in a standard way such that it can be reproduced after the nail is inserted. Through a unicortical drill hole, the nail is palpated with the tip of a Kirschner wire and systematic maneuvers allow the Kirschner wire to palpate and fall into the locking hole. The Kirschner wire is tapped across the second cortex before drilling. The screw is inserted, and the ball-tipped insertion guidewire is placed back into the nail to palpate the crossing screw confirming position. We treated 16 patients with 18 long bone fractures using the described technique. We assessed patients clinically and radiographically immediately postoperatively. A total of 19 blind freehand interlocks were attempted, and 17 were successful as assessed by direct intraoperative observations and by postoperative radiographs. We describe a simple technique for performing static locked intramedullary nailing of the femur and tibia without fluoroscopy. This technique was successful in most cases and is intended for use with any nailing system only when fluoroscopy or specialized systems for nailing without fluoroscopy are not available.

Static intramedullary nailing as final treatment of pathological femoral fracture secondary to contaminated primary hydatid cyst: a case report and review of the literature

Echinococcosis (hydatid cyst disease) in humans is a rare parasitic disease that primarily involves the liver and the lungs. Skeletal manifestation of the disease is seldom and often presents as a clinical and radiological problem. The contamination of the primary hydatid cyst complicates the treatment which is also difficult because of the invasive nature of bone involvement and the spillage of fluid with subsequent contamination seeding. We present a case of pathological femoral fracture secondary to contaminated primary hydatid cyst that has been finally treated with static intramedullary nailing. We highlight the importance of including the hydatid bone disease in the differential diagnosis of destructive bone lesions, and we suggest the intramedullary nailing as the final treatment of specific type of pathological fractures.

Pudendal Nerve Palsy Following Static Intramedullary Nailing of the Femur

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

The Treatment of the Femoral Diaphyseal Fracture with Intramedullary Nailing: A Review of 313 Cases

Purpose: The purpose of this study is to present our experience of interlocking intramedullary nailing in the treatment of femoral fractures and to report the results and the complications. Material and Method: In a period of nine years (1993-2001) were treated 313 diaphyseal fractures 228 with AIM titanium intramedullary nailing and 85 with Gross-Kempf. All femoral fractures were reamed except the pathological fractures.The 313 fractures according to AO classification were divided as follows:Type A 81 (25.9 %), Type B 132 (42.8 %) and Type C 100 (31.3 %). The 89 % of fractures were caused by high energy injuries (traffic accidents). The mean age was 26 yrs (17-78 yrs). From all fractures 256 were closed and 57 were open (grade I: 27, grade II 19, grade III a 11). For type A fractures dynamic intramedullary nailing was the treatment of choice, while in type B, C fractures static intramedullary nailing was performed. In all patients we used prophylactic antibiotics for 48 hours and low weight molecular heparin for a month. The median time of radiation exposure was 16 sec (range 5-42). From the second postoperative day we encourage our patients to walk with partial weight bearing, except those with type C fractures who started their weight bearing after 3 weeks.EM EMTYPE="BOLD">Results: All type A fractures were united in an average time of 16 weeks, type B in 20 weeks and type C in 23 weeks. In regard to complications, we had: 5 aseptic pseudarthrosis (1.6 %), 12 delayed unions (3.8 %), torsional malunion (5°) in 3 patients (0.96 %). The majority of them were treated with intramedullary nailing revision. In 4 patients (1.28 %) we had limb shortening of 15 mm. (In one case we made dynamic nailing instead of the correct static intramedullary nailing and in 3 cases we failed to centralize the proximal screw. All of them were reoperated.)Neurological complications were observed postoperatively in 29 patients, 22 with paresis of the pudendal nerve, due to traction (all recovered in a month), and 7 with paresis of peroneal nerve which were recovered in 3 months. There was found 23 broken screws but no broken nail. In one case of pathological fracture (lower 1/3) the guide wire was penetrate in the knee join.We had two pulmonary and one fat embolism (in patients without chest injury), but none of them was fatal. Also we noticed no superficial or deep infections and we didn't have a case of compartment syndrome. In two patients was observed clinically thrombosis below knee.Patients returned to their previous activities in a mean time of 12 weeks. Conclusion: Locking intramedullary nailing offers excellent results in treatment of femoral diaphyseal fractures. We choose AIM titanium nail because the modulus of elasticity is more closer with bone elasticity. Also the fatigue strength, yield strength and ultimate tensile strength, are higher than any other implant. For this reasons we can use smaller diameter nails, with less reaming, and less disturbance of endosteal blood supply.

Gamma and other cephalocondylic intramedullary nails versus extramedullary implants for extracapsular hip fractures.

Cephalocondylic intramedullary nails which are inserted proximally to distally (cephalocondylic) have been used for the surgical treatment of extracapsular hip fractures. To update and expand our review comparing the Gamma nail with the sliding hip screw (SHS) by comparing all cephalocondylic intramedullary nails with extramedullary implants for the surgical treatment of extracapsular hip fractures in adults. We searched the Cochrane Musculoskeletal Injuries Group trials register, Medline, select orthopaedic journals and conference proceedings, and reference lists of relevant articles. We contacted trialists, colleagues and implant manufacturers. Date of the most recent search: June 1998. All randomised and quasi-randomised trials comparing cephalocondylic nails with extramedullary implants for extracapsular hip fractures. Both reviewers independently assessed trial quality and extracted data. Additional information was sought from all trialists. Wherever appropriate and possible, results were pooled. The one trial of 230 patients comparing the Kuntscher-Y nail with the SHS, reported no major difference the outcome aside from a significantly increased number of patients with leg shortening, and a tendency for poorer recovery of mobility in the Kuntscher-Y nail group. Fourteen trials comparing the Gamma nail with the SHS were included, with data available for 1977 patients. The Gamma nail was associated with an increased risk of operative and later fracture of the femur and an increased re-operation rate. There were no major differences in the incidence of wound infection, mortality or medical complications between implants. Data were inadequate to determine if there were differences for other outcomes. Two trials involving 231 patients compared the intramedullary hip screw (IMHS) with the SHS. Fracture fixation complications were more common in the IMHS group: all cases of operative and later fracture of the femur and haematoma occurred in this group. Results for post-operative complications, mortality and functional outcomes were similar in the two groups. Further evidence is required before any conclusions can be drawn on the relative merits of the Kuntscher-Y nail and the SHS. Given the lower complication rate of the SHS in comparison with the Gamma nail, it appears that for trochanteric fractures the SHS is superior. Further evidence is still required to confirm this, as well as to determine if the Gamma nail, or modifications of the Gamma nail, have advantages for selected fracture types (for example, subtrochanteric fractures). From the limited evidence available, IMHS appears to have the same problems as the Gamma nail, but other theoretical advantages of the IHMS can not be ruled out.

Setscrew distal locking for intramedullary nails: a biomechanical study.

This biomechanical study was undertaken to examine the effectiveness of setscrew distal locking in a static intramedullary (IM) femoral nail on the stability of fixation of femoral shaft fractures. Fifteen fresh-frozen cadeveric femora were randomly separated into three groups of five bones and transversely sectioned immediately distal to the isthmus. After the insertion of the large-diameter nails, distal locking was obtained by conventional method in the first group. In the second group, set-screw design was used in which two transverse screws penetrated only the lateral cortex of the femur and compressed the nail in the intramedullary canal. No distal locking was used in the third group. All instrumented femurs were mounted on a servohydraulic testing machine and tested in both rotations (20 degrees) and axial compression (amplitude: 1,000 Newton). Loading-versus-displacement data, acquired at a ten-Hertz sampling rate, were calibrated and used to calculate maximum torque, stiffness, and energy capacity to failure. Maximum displacement and axial stiffness also were determined. Mean maximum torque at 10 degrees for each group were 15.3+/-4.8 newton-meters for the interlocking group, 8.5 +/-1.2 newton-meters for the setscrew group, and 3.6+/-2.7 newton-meters for the nonlocked femora. At 20 degrees of rotational displacement, the torque measured 37.4+/-2.6 newton-meters; 15.0+/-4.0 newton-meters; and 5.3+/-3.1 newton-meters, respectively (p < 0.05). Mean torsional stiffness was 1.17+/-0.76 newton-meters per degree for the setscrew group and 1.34+/-0.83 newton-meters per degree for the interlocking group (p > 0.05). The setscrew design provided 87 percent of the torsional rigidity of the interlocking group. In the axial compression test, mean maximum shortening was 1.1+/-0.3 millimeters in the interlocking group and 1.4+/-0.6 millimeters in the setscrew group (p > 0.05). The mean stiffness on longitudinal compression provided by the interlocking screws and the setscrews was 918 and 860 newton-meters per millimeter, respectively. The distal setscrew design provides adequate distal fixation of intramedullary nail for patients in the postoperative rehabilitation period of the femoral shaft fractures treated with intramedullary nailing.

Optimal location of a single distal interlocking screw in intramedullary nailing of distal third femoral shaft fractures.

This biomechanical study was done to determine the effect of the level of a single distal screw in a static intramedullary (IM) femoral nail on the stability of fixation of a fracture in the distal third of the femur. Fifteen composite fiberglass femora were osteotomized transversely in the distal third of the femur. A Grosse-Kempf nail was implanted into the femurs, which were divided into three groups of five specimens. Single screw distal nail locking was varied distal to the osteotomy site for each group at 2.5, 5.0, and 7.5 centimeters, respectively. All instrumented femurs were mounted on a servohydraulic testing machine and fitted with transducers to measure axial, rotational, and bending displacements. Specimens were cyclically loaded (one hertz) in simultaneous torsion (moment: +/- 10 newton-meters) and axial compression (amplitude: 2,000 newtons) for 500 cycles with a 250-pound abductor force. Data from linear and rotational transducers were sampled at 100 hertz for five cycles before cycling, every 100 cycles of loading, and immediately after cycling. Custom computer software was developed to convert transducer signals into static and dynamic measurements of axial motion (in millimeters), rotation (in degrees), and angulation (in degrees). Osteotomy site dynamic rotation increased significantly in specimens locked at 7.5 centimeters when compared with the 2.5-centimeter group. There was minimal difference between the stability of the 5.0-centimeter and 7.5-centimeter groups. There was no significant change in position at the fracture site before or after cyclic loading with respect to axial shortening, rotation, or bending. Both dynamic axial and angular displacements were also unaffected by screw position. The location of a single distal interlocking screw in static IM nail fixation of distal third femur fractures can significantly affect rotational stability but not axial or angular fixation.