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Precise placement of lag screws in operative treatment of trochanteric femoral fractures with a new guide system
Accepted Manuscript Title: Precise placement of lag screws in operative treatment of trochanteric femoral fractures with a new guide system Author: Oguz S. Poyanli Salih Soylemez Afsar T. Ozkut Esat Uygur Bahattin Kemah Omer K. Unal PII: DOI: Reference:
S0020-1383(15)00331-9 http://dx.doi.org/doi:10.1016/j.injury.2015.06.003 JINJ 6243
To appear in:
Injury, Int. J. Care Injured
Received date: Revised date: Accepted date:
28-11-2014 10-5-2015 2-6-2015
Please cite this article as: Poyanli OS, Soylemez S, Ozkut AT, Uygur E, Kemah B, Unal OK, Precise placement of lag screws in operative treatment of trochanteric femoral fractures with a new guide system, Injury (2015), http://dx.doi.org/10.1016/j.injury.2015.06.003 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
PRECISE PLACEMENT OF LAG SCREWS IN AN OPERATIVE TREATMENT OF TROCHANTERIC FEMORAL FRACTURES WITH A NEW GUIDE SYSTEM AND TROCHANTERIC NAIL. Oguz S. POYANLI, Associate Professor, S.B. Göztepe Training and Research Hospital, Department of Orthopaedics and Traumatology. Istanbul, Turkey. e-mail; [email protected]. Salih SOYLEMEZ, MD, Bingöl State Hospital, Department of Orthopaedics and Traumatology, Bingöl, Turkey e-mail:[email protected] Afsar T. OZKUT, MD, Istanbul Medeniyet University, Göztepe Training and Research Hospital, Department of Orthopaedics and Traumatology. Istanbul, Turkey. e-mail; [email protected]. *Esat UYGUR, MD, Istanbul Medeniyet University, Göztepe Training and Research Hospital, Department of Orthopaedics and Traumatology. Istanbul, Turkey. e-mail; [email protected] Bahattin KEMAH, MD, Istanbul Medeniyet University, Göztepe Training and Research Hospital, Department of Orthopaedics and Traumatology. Istanbul, Turkey. e-mail; [email protected]. Omer K. UNAL, MD, Göztepe Training and Research Hospital, Department of Orthopaedics and Traumatology. Istanbul, Turkey. e-mail; [email protected]. *Corresponding author; Address: Eğitim Mah. Doktor Erkin Cad. Göztepe Eğitim ve Araştırma Hastanesi Ortopedi ve Travmatoloji Kliniği. 34732 Kadıköy-İstanbul/Turkey. Phone:+90216 570 91 05
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e-mail: [email protected].
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PRECISE PLACEMENT OF LAG SCREWS IN OPERATIVE TREATMENT OF
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TROCHANTERIC FEMORAL FRACTURES WITH A NEW GUIDE SYSTEM
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ABSTRACT
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Purpose: We assessed the accuracy of a new guide system that we developed to place lag
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screws in the proper position with the minimum number of attempts for operative treatment of
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trochanteric femoral fractures.
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Methods: A total of 55 consecutive trochanteric femoral fractures were treated with a
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cephalomedullary nail. The first 27 consecutive patients were treated with the standard
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operation (group A), while the new guide system was used in the last 28 consecutive patients
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(group B). The numbers of attempts to place K wires and the duration of surgery were noted.
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Accuracy of lag screw placement was evaluated by measuring the angle of deviation from the
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central axis of the femoral head.
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Results: Deviation values ranged from –11° to +15° for the 27 cases in group A, with a
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median absolute deviation of 8°±6°. That in the 28 cases after the introduction of the new
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guide system (group B) ranged from –5° to +6°, with a median absolute deviation of 0.5°±3°
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(P<0.001). The total numbers of attempts to place lag screws and mean operation time
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decreased significantly after introduction of the new guide system (P<0.001).
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Conclusions: With this new guide system, we are able to insert lag screws successfully in the
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optimal position even in most unstable fractures. The present study indicated that this new
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guide system and nail facilitate accurate placement of lag screws in the appropriate position
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with the minimum number of attempts.
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Keywords:
Trochanteric femoral fractures; Operative treatment; Cephalomedullary nail; Guide system. 3
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Introduction The most common cause of failure after operative treatment of intertrochanteric fracture is “cutout” of
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the lag screw within the femoral head. The bone density of the femoral head, the type of fracture, and the
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accuracy of reduction are considered to contribute to such lag screw cutout. Patients with unstable trochanteric
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hip fractures and osteoporotic bone are in the highest risk group for cutout, regardless of the device used [1]. In
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addition to the bone density of the femoral head and type of fracture, the position of the lag screw within the
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femoral head is an important factor in the success or failure of the implant. Based on theoretical and
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experimental considerations, the most appropriate lag screw location is inferior in the frontal plane and central in
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the sagittal plane [2, 3]. However, accurate positioning is achieved in less than 50% of cases [4, 5].
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To reduce the incidence of cutout, it is essential to pay particular attention to placement of the lag screw
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in the femoral head. We developed a new improved guide system to insert lag screws with the minimum number
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of attempts into the optimal position—exactly central on the lateral view—and to prevent any additional damage
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to the osteoporotic lateral cortex, which may result from several K wire insertion attempts. This study was
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performed to determine the accuracy of our new guide system.
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Patients and Methods
A total of 55 consecutive trochanteric femoral fractures were treated with a cephalomedullary nail
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(TRON; Tıpsan Medikal, Istanbul, Turkey), by two surgeons randomly, between October 2011 and December
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2012 at our hospital regardless of fracture pattern. The first 27 consecutive patients were treated using the
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standard procedure (Group A), while all lag screws were inserted using the new guide system in the last 28
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consecutive patients (Group B).
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“TRON” is an anatomical nail, available in lengths of 180, 200, and 220 mm, with a proximal diameter
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of 16 mm at the trochanteric region, and 10, 11, and 12 mm distally. The neck shaft angle is 125° with 5°
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mediolateral curvature. At proximal part it has two lag screw holes. To decrease the excessive rigidity of the
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implant and compressive loads at the tip of the nail, the distal end of the nail is cleaved in four (Fig 1a). In
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accordance with the proximal femoral anatomy, lag screws can be placed at 15° anteversion with a targeting
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device in parallel to the femoral shaft in the frontal plane (Fig 1d).
The new guide system is composed of two arms anteverted by 15°. Both arms contain holes 3.0 mm in
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diameter to which K wires are applied (Fig 1b, d). Two arms aim to be used at both right and left hip fractures.
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The device is applied to the proximal end of the targeting device (by two columns which sits to the holes on the
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targeting device) to use the K-wire as a projection for where the lag screw wire will be placed on the lateral view
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which minimizes the number of K-wire pilot holes drilled into the "at risk" lateral cortex (Fig 1c, d).
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The patients consisted of 33 women and 22 men with a mean age of 80.1 ± 10.3 years. Fracture types
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according to the AO classification [6] were as follows: A1.1, n = 4; A1.2, n = 9; A1.3, n = 5; A2.1, n = 6; A2.2, n
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= 14; A2.3, n = 12; A3.2, n = 1; and A3.3, n = 4. There were 18 fractures of the stable type and 37 fractures of
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the unstable type in the study population. Type of fractures were statistically similar in each group (p=0,456)
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(Table 1).
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Numbers of attempts to place K wires in an appropriate position and total operation time were noted. To
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evaluate the accuracy of lag screw placement on lateral radiographs, the deviation angle between the axis of the
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lag screw and the femoral head was measured on all lateral radiographs obtained immediately postoperatively, as
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described by Nishiura et al. [7]. Two surgeons measured the deviation angles independently. Measurements
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were made for the 27 fractures in group A and 28 fractures in group B (Fig 2).
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For statistical analyses, the independent-samples t test and Mann–Whitney U-test were used to compare
the independent groups. The partial correlation test was used to examine correlations between parameters.
Surgical case using the new guide system
The patient was positioned supine on a traction table. After reduction maneuver, the limb was prepared
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in a standard fashion. For best assessment of the center of the femoral head and neck, a true lateral view was
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obtained to achieve alignment of the axis of the femoral neck congruent with the axis of the femoral shaft (Fig
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3a, b). A lateral view can also be used, but the true lateral view is preferred, because the lateral view does not
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necessarily reflect the real center of the head (Fig 3c, d). An image intensifier was positioned at an angle of 40°
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to the affected limb and perpendicular to the lag screw in the frontal plane. If reduction in the lateral view was
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not acceptable, the position of the proximal fragment was improved intraoperatively by anteroposterior (AP)
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pressure through an anteriorly placed rasp through the same skin incision and then a true lateral view was
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obtained.
After insertion of the nail, distal lag screw was inserted first. The position of the lag screw was adjusted
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on the AP view and the lag screw guide pin was introduced and placed on the lateral cortex. The new guide
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system was added to the targeting device with its concave side facing the patient. A guide pin was added to the
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posterior arm of the guide system and stopped on the skin (Fig 4a). The true lateral view was assessed. At this
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stage, the guide pin must be seen on the center of the femoral head (Fig 4b). If the guide pin cannot be seen on
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the center of the head, the targeting device is rotated anteriorly or posteriorly until the guide pin is seen on the
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center of the femoral head. If, in lack of experienced staff a true lateral view could not be obtained, a lateral view
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is used to place the guide pins. The arms of the guide are 15° anteverted with reference to the femoral neck.
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Thus, positioning the guide pin parallel to the femoral neck on the lateral view indicates that the lag screw guide
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pin can be introduced correctly (Fig 5a). The direction of the second (proximal) lag screw will be the same with
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the first (distal) screw. So there is no need to arrange anteversion for second screw. After appropriate placement
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of lag screw guide pins, lag screws were introduced and an initial true lateral view was obtained (Fig 5b).
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Results
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The median value of absolute deviation showed a significant difference between groups A and B (P <
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0.001). When we measured the deviation angle in all 55 cases, the values were –11° to +15° for the 27 cases in
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group A (median value of absolute deviation = 8 ± 6°); the deviation was 0° in four cases. In the 28 cases after
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introduction of the new guide system (group B), the deviation ranged from –5° to +6° (median value of absolute
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deviation = 0.5° ± 3°); the deviation was 0° in 18 cases (Table 2; Graphic 1).
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The median number of attempts to place K wires was also significantly different between groups A and
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B (P < 0.001). The total number of attempts to place lag screws was 80 for the 27 cases in group A (median, 3 ±
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2). Among them, the lag screws were placed at the first or second attempt in only four and at eight cases,
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respectively. The total number of attempts to place lag screws was 38 for the 28 cases in group B (median, 1 ±
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1). In 18 cases, lag screws were placed at the first attempt, and at the second attempt in another 10 cases (Table
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2; Fig 6). The mean operation time decreased significantly after introduction of the new guide system (P <
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0.001). The mean operation times were 54.7 ± 8.8 min in group A and 46.5 ± 7.5 min in group B (Table 2).
In group A, a positive correlation was found between different AO fracture patterns and operation time
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(r=0,470), deviation from the central axis of the femoral head (r=0,417), and attempts to place K wires(r=0,466).
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However, in group B, there was no correlation between AO fracture patterns and operation time, deviation from
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the central axis of the femoral head, or attempts to place K wires.
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Discussion
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In operative treatment of trochanteric femoral fractures, implant-related postoperative complications
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using intramedullary nails (IMNs) are still common, compared with sliding hip screws (SHS), despite their
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biomechanical superiority over SHS [8– 10]. Cutout, which is a serious complication of the surgical treatment of
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trochanteric fractures, usually requires revision surgery. The incidence of cutout after use of IMNs varies from
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1.3% to 10% in different reports [7, 11 – 13].
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Various studies have examined the optimum place for the lag screw in the femoral head and best
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predictive factors for cutout in intertrochanteric fractures. Bojan et al. [14] noted that cutout was related to three
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key factors—complex fracture types, unsatisfactory anatomical reduction, and malposition of lag screws—and
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that a combination of several factors occurred in most cutout cases. Baumgaertner et al. [ 4] noted that the tip
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apex index was the most valuable parameter for predicting lag screw cutout. In contrast, Kawaguchi et al. [11]
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used Asiatic gamma nails to treat 60 intertrochanteric fractures. Their study showed that rather than the degree of
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osteoporosis, the type of fracture, or the accuracy of the reduction, the cutout index, calculated by multiplying
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the distance of the screw tip from the subchondral bone on the AP view and distance of the screw tip from the
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central axis of the femoral head on the lateral view, was the most valuable parameter for predicting cutout.
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Nishiura et al. [7] measured deviation angles between the axis of the lag screw and the femoral head to assess the
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position of the lag screw in the femoral head. They determined that the correct placement of the lag screws had a
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deviation of less than ±5° from the central axis. The advantages of this method are that the value of the angle
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does not change with different degrees of magnification with the image intensifier and it is easy to perform. Most
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studies have indicated that failures occur when the lag screw has been placed anteriorly, posteriorly, or
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superiorly [4, 5, 15]. There is a general consensus that the lag screw should be placed centrally in the lateral plane
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and centrally [4, 5, 16] or inferiorly [2, 15] in the AP plane.
There have been several previous studies regarding how to place the lag screw appropriately in the
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femoral head. Nishiura et al. reported that to place the lag screw in the femoral head centrally, true lateral images
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had to be obtained and concluded that the targeting device had to be seen as a square in the true lateral images to
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verify accurate screw placement [7]. Park et al. investigated the pin shift phenomenon and suggested that further
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comprehensive evaluations are required [17].
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However, the criteria defined in previous studies to determine accurate positioning of the lag screw
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intraoperatively have been subjective and the screws can be placed most accurately only by experienced
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surgeons. As intertrochanteric fracture surgery is one of the most common surgical procedures performed, a
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guide system that can be used easily by any surgeon is needed. Our targeting device consists of two arms with
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angles of 15°. This device can be manufactured and adapted readily to other targeting devices and used with
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other nails that are commercially available.
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The finding of a positive correlation between the AO fracture type and the median deviation of the
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screw from the central axis of the femoral head and the median number of K wires used in the A subgroup of
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patients showed that the surgical procedure becomes more difficult with decreasing fracture stability. As the
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number of K wire entrance points increases with more unstable fractures, loss of reduction may occur, although
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anatomical reduction had been obtained previously. Repeated anterior and posterior rotation of the targeting
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device to place the K wire in the appropriate position in the sagittal plane may account for the loss of reduction.
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As a result, as the stability decreases, the number of K wire entry points and operative time increase and the K
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wires cannot be placed centrally in the lateral plane. Similarly, in group A, K wires were placed in an acceptable
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position (±5°) in only 10/27 (37%) patients.
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In the group B patients, there were no correlations between AO fracture type, median deviation of the
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screw, median number of K wire entrance points, or operative time. The new guiding system allowed placement
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of K wires without violating the lateral cortex and with minimum effort. Thus, anatomical reduction is not lost
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even in unstable fractures and K wires may be placed with maximum accuracy in the minimum amount of time.
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Excluding the two patients in the B subgroup with 6° deviation, K wires were placed accurately (±5°) in the
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lateral images in all of the other patients. This resulted in significantly shorter operation periods.
Limitations of this study include the small numbers of patients and the lack of long-term follow-up to
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evaluate the measurement method and cutout rates between the two groups. Patients that we weren't able to get a
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true lateral view were not recorded so how that effected the number of K-wire penetrations, or time, etc could
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not be discussed.
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Conclusions
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In conclusion, with the new guide system, at least we were able to insert the lag screw successfully in
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the optimal position, even in most unstable fractures and prevent loss of anatomical reduction obtained during
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surgery. The present study indicated that this new guide system allow accurate lag screw placement in the proper
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position with the minimum number of attempts.
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2- Parker MJ. Cutting-out of the dynamic hip screw related to its position. J Bone Joint Surg Br
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fractures: the prognostic value of osteoporosis. J Orthop Trauma 1993;7(5):438.
1992;74:625.
3- Wu CC, Shih CH, Lee MY, et al. Biomechanical analysis of location of lag screw of a dynamic hip
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1- Barrios C, Brostrom LA, Stark A, et al. Healing complications after internal fixation of trochanteric hip
screw in treatment of unstable intertrochanteric fracture. J Trauma 1996;41(4):699-702.
4- Baumgaertner MR, Curtin SL, Lindskog DM, et al. The value of the tip apex distance in predicting
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1995;44:227–53.
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Orthopaedic Trauma Association Classification, Database and Outcomes Committee. J Orthop Trauma
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7- Nishiura T, Nozawa M, Morio H. The new technique of precise insertion of lag screw in an operative
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treatment of trochanteric femoral fractures with a short intramedullary nail. Injury 2009;40:1077–83
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8- Bridle SH, Patel AD, Bircher M, et al. Fixation of intertrochanteric fractures of the femur: a randomised
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prospective comparison of the Gamma nail and the dynamic hip screw. J Bone Joint Surg Br
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9- Jones HW, Johnston P, Parker M. Are short femoral nails superior to the sliding hip screw? A metaanalysis of 24 studies involving 3,279 fractures. Int Orthop 2006;30(2):69–78.
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10- Parker MJ, Handoll HH. Gamma and other cephalocondylic intramedullary nails versus extramedullary
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implants for extracapsular hip fractures. Cochrane Database Syst Rev 2008;16(July (3)). CD000093.
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11- Kawaguchi S, Sawada K, Nabeta Y. Cutting-out of the lag screw after internal fixation with the Asiatic
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gamma nail. Injury 1998;29(1):47-53.
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12- Adams CI, Robinson CM, Court-Brown CM, et al. Prospective Randomized Controlled Trial of an
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Intramedullary Nail Versus Dynamic Screw and Plate for Intertrochanteric Fractures of the Femur. J
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Orthop Trauma 2000;15(6):394-400.
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13- Simmermacher RKJ, Ljungqvist J, Bail H, Hockertz T, et al. The new Proximal femoral antirotation (PFNA) in daily practice: Results of a multicentre clinical study. Injury 2008;39:932-9.
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14- Bojan A, Taglang G, Beimel C, et al. A retrospective analysis of cut out complications in 3066 patients
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treated with Gamma nails. In: The 9th Conference of the International Society for Fracture Repair in
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Bologna; 2004;p. 4–5. News AIOD.
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fractures: an evaluation of 937 patients. Int Orthop 2010;34(8):1273-6.
16- Larsson S, Friberg S, Hansson LI. Trochanteric fractures. Influence of reduction and implant position
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15- Hsueh KK, Fang CK, Chen CM, et al. Risk factors in cut-out of sliding hip screw in intertrochanteric
on impaction and complications. Clin Orthop Relat Res 1990;259:130–9. 17- Park J, Park SY, Yoon HK, Kim DY, Lee HY, Yang KH. Correction of lag screw guide pins
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inappropriately placed during intramedullary hip nailing. Injury 2008;39(10):1134-40.
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The English in this document has been checked by at least two professional editors, both native speakers of
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English. For a certificate, please see:
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http://www.textcheck.com/certificate/HH3JMe
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Figure 1. A. Trochanteric nail (TRON) B. The new guide system has two arms that are
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anteverted by 15°, with 3.0-mm K wire holes. C. The holes mounting with the new guide
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system at the superolateral end of the targeting device (red arrows). D. The targeting device
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and the new guide system used together. The guide pin, applied to the posterior arm, is in the
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same line as the drill guide sleeve.
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Figure 2. Measured deviation angles between the axis of the lag screw and the femoral head.
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A. +4° (anterior) deviation from the central axis of the femoral head. B. –9° (posterior)
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deviation from the central axis of the femoral head. C. 0° deviation from the central axis of
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the femoral head. Centrally positioned screw. D. 0° deviation from the central axis of the
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femoral head. Centrally positioned screw. TM, trochanter major.
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Figure 3. A. True lateral view. The image intensifier in inclined by approximately 20° from
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the coronal plane. B. Alignment of the axis of the femoral neck congruent with the axis of the
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femoral shaft obtained on the true lateral view. C. Lateral view of neck and head of femur. D.
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Neck and head of the femur seen anteverted on lateral view.
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Figure 4. A. New guide system added to the targeting device. A guide pin added to the
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posterior arm of the guide system and stopped on the skin. B. Guide pin on the center of the
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femoral head in the true lateral view. C. Guide pin and lag screw guide pin seen in the same
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line.
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Figure 5. A. Guide pin and neck of the femur seen parallel in the lateral view. Lag screw
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guide pin seen in the center of the femoral head. B. Initial radiograph obtained after the
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operation.
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Graphic 1. Median values of absolute deviation angles and numbers of attempts for all
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patients.
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Table 1. Preoperative Patient Data
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Table 2. İntraoperative Patient Data
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Acknowledgement: No funding has been recevied for this study. Authors thank to “Tıpsan Medikal” for
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providing the guide system which has been used in this study.
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Table 1
Table 1
Preoperative Patient Data Group B No. (%) Total No.
(%)
No. hips
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Mean age(y) 80,1±10,3
76,7±10,6
Gender(M/F)
12/15
28
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Fracture patterns
28
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11(40,7%)
10/18
14(51,9%)
18(64,3%)
AO type III
2(7,4%)
3(10,7%
11(40,7%)
7(25%)
16(59,3%)
21(75%)
22/33
5(9,1%)
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Unstable (AO type 2 and 3) 37(67.3%)
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AO type II 32(58,2%)
Stable (AO type 1) 18(32,7%)
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7(25%)
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AO type I 18(32,7%)
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83,3±9,1
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Table 2
Table 2
İntraoperative Patient Data Group A No. Median value of absolute deviation (Median±IQR*).
Group B No.
8±6
0,5±3
Stable Fractures (AO type I)
4±8
Unstable Fractures (AO type II and III)
9±5
No. 0˚ deviation
1±3 14
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0±5
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different fracture patterns (Median±IQR*)
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Median value of absolute deviation for
No. 0˚ deviation for different
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fracture patterns Stable Fractures (AO type I)
No. total attempts** Median value of attempt (Median±IQR)
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No. 1 attempt
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Unstable Fractures (AO type II and III)
3
4
1
10
80
38
3±2
1±1
4
18
2±2
1±0
3,5±3
1±1
54,7±8,8
46,5±7,5
51±7,2
45,3±11
Median value of attempt for different fracture patterns (Median±IQR)
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Stable Fractures (AO type I)
Unstable Fractures (AO type II and III)
Mean surgery duration (min.)
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Mean surgery duration for different fracture patterns (min.)
Stable Fractures (AO type I) Unstable Fractures (AO type II and III)
57,2±9
46,9±6,2
. *Inter Quartile Range **attempts to place K wire in an appropriate position in lateral view.
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Figure 5
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S0020-1383(15)00331-9 http://dx.doi.org/doi:10.1016/j.injury.2015.06.003 JINJ 6243
To appear in:
Injury, Int. J. Care Injured
Received date: Revised date: Accepted date:
28-11-2014 10-5-2015 2-6-2015
Please cite this article as: Poyanli OS, Soylemez S, Ozkut AT, Uygur E, Kemah B, Unal OK, Precise placement of lag screws in operative treatment of trochanteric femoral fractures with a new guide system, Injury (2015), http://dx.doi.org/10.1016/j.injury.2015.06.003 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
PRECISE PLACEMENT OF LAG SCREWS IN AN OPERATIVE TREATMENT OF TROCHANTERIC FEMORAL FRACTURES WITH A NEW GUIDE SYSTEM AND TROCHANTERIC NAIL. Oguz S. POYANLI, Associate Professor, S.B. Göztepe Training and Research Hospital, Department of Orthopaedics and Traumatology. Istanbul, Turkey. e-mail; [email protected]. Salih SOYLEMEZ, MD, Bingöl State Hospital, Department of Orthopaedics and Traumatology, Bingöl, Turkey e-mail:[email protected] Afsar T. OZKUT, MD, Istanbul Medeniyet University, Göztepe Training and Research Hospital, Department of Orthopaedics and Traumatology. Istanbul, Turkey. e-mail; [email protected]. *Esat UYGUR, MD, Istanbul Medeniyet University, Göztepe Training and Research Hospital, Department of Orthopaedics and Traumatology. Istanbul, Turkey. e-mail; [email protected] Bahattin KEMAH, MD, Istanbul Medeniyet University, Göztepe Training and Research Hospital, Department of Orthopaedics and Traumatology. Istanbul, Turkey. e-mail; [email protected]. Omer K. UNAL, MD, Göztepe Training and Research Hospital, Department of Orthopaedics and Traumatology. Istanbul, Turkey. e-mail; [email protected]. *Corresponding author; Address: Eğitim Mah. Doktor Erkin Cad. Göztepe Eğitim ve Araştırma Hastanesi Ortopedi ve Travmatoloji Kliniği. 34732 Kadıköy-İstanbul/Turkey. Phone:+90216 570 91 05
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e-mail: [email protected].
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PRECISE PLACEMENT OF LAG SCREWS IN OPERATIVE TREATMENT OF
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TROCHANTERIC FEMORAL FRACTURES WITH A NEW GUIDE SYSTEM
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ABSTRACT
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Purpose: We assessed the accuracy of a new guide system that we developed to place lag
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screws in the proper position with the minimum number of attempts for operative treatment of
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trochanteric femoral fractures.
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Methods: A total of 55 consecutive trochanteric femoral fractures were treated with a
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cephalomedullary nail. The first 27 consecutive patients were treated with the standard
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operation (group A), while the new guide system was used in the last 28 consecutive patients
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(group B). The numbers of attempts to place K wires and the duration of surgery were noted.
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Accuracy of lag screw placement was evaluated by measuring the angle of deviation from the
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central axis of the femoral head.
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Results: Deviation values ranged from –11° to +15° for the 27 cases in group A, with a
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median absolute deviation of 8°±6°. That in the 28 cases after the introduction of the new
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guide system (group B) ranged from –5° to +6°, with a median absolute deviation of 0.5°±3°
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(P<0.001). The total numbers of attempts to place lag screws and mean operation time
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decreased significantly after introduction of the new guide system (P<0.001).
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Conclusions: With this new guide system, we are able to insert lag screws successfully in the
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optimal position even in most unstable fractures. The present study indicated that this new
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guide system and nail facilitate accurate placement of lag screws in the appropriate position
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with the minimum number of attempts.
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Keywords:
Trochanteric femoral fractures; Operative treatment; Cephalomedullary nail; Guide system. 3
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Introduction The most common cause of failure after operative treatment of intertrochanteric fracture is “cutout” of
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the lag screw within the femoral head. The bone density of the femoral head, the type of fracture, and the
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accuracy of reduction are considered to contribute to such lag screw cutout. Patients with unstable trochanteric
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hip fractures and osteoporotic bone are in the highest risk group for cutout, regardless of the device used [1]. In
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addition to the bone density of the femoral head and type of fracture, the position of the lag screw within the
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femoral head is an important factor in the success or failure of the implant. Based on theoretical and
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experimental considerations, the most appropriate lag screw location is inferior in the frontal plane and central in
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the sagittal plane [2, 3]. However, accurate positioning is achieved in less than 50% of cases [4, 5].
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To reduce the incidence of cutout, it is essential to pay particular attention to placement of the lag screw
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in the femoral head. We developed a new improved guide system to insert lag screws with the minimum number
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of attempts into the optimal position—exactly central on the lateral view—and to prevent any additional damage
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to the osteoporotic lateral cortex, which may result from several K wire insertion attempts. This study was
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performed to determine the accuracy of our new guide system.
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Patients and Methods
A total of 55 consecutive trochanteric femoral fractures were treated with a cephalomedullary nail
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(TRON; Tıpsan Medikal, Istanbul, Turkey), by two surgeons randomly, between October 2011 and December
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2012 at our hospital regardless of fracture pattern. The first 27 consecutive patients were treated using the
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standard procedure (Group A), while all lag screws were inserted using the new guide system in the last 28
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consecutive patients (Group B).
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“TRON” is an anatomical nail, available in lengths of 180, 200, and 220 mm, with a proximal diameter
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of 16 mm at the trochanteric region, and 10, 11, and 12 mm distally. The neck shaft angle is 125° with 5°
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mediolateral curvature. At proximal part it has two lag screw holes. To decrease the excessive rigidity of the
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implant and compressive loads at the tip of the nail, the distal end of the nail is cleaved in four (Fig 1a). In
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accordance with the proximal femoral anatomy, lag screws can be placed at 15° anteversion with a targeting
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device in parallel to the femoral shaft in the frontal plane (Fig 1d).
The new guide system is composed of two arms anteverted by 15°. Both arms contain holes 3.0 mm in
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diameter to which K wires are applied (Fig 1b, d). Two arms aim to be used at both right and left hip fractures.
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The device is applied to the proximal end of the targeting device (by two columns which sits to the holes on the
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targeting device) to use the K-wire as a projection for where the lag screw wire will be placed on the lateral view
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which minimizes the number of K-wire pilot holes drilled into the "at risk" lateral cortex (Fig 1c, d).
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The patients consisted of 33 women and 22 men with a mean age of 80.1 ± 10.3 years. Fracture types
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according to the AO classification [6] were as follows: A1.1, n = 4; A1.2, n = 9; A1.3, n = 5; A2.1, n = 6; A2.2, n
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= 14; A2.3, n = 12; A3.2, n = 1; and A3.3, n = 4. There were 18 fractures of the stable type and 37 fractures of
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the unstable type in the study population. Type of fractures were statistically similar in each group (p=0,456)
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(Table 1).
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Numbers of attempts to place K wires in an appropriate position and total operation time were noted. To
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evaluate the accuracy of lag screw placement on lateral radiographs, the deviation angle between the axis of the
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lag screw and the femoral head was measured on all lateral radiographs obtained immediately postoperatively, as
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described by Nishiura et al. [7]. Two surgeons measured the deviation angles independently. Measurements
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were made for the 27 fractures in group A and 28 fractures in group B (Fig 2).
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For statistical analyses, the independent-samples t test and Mann–Whitney U-test were used to compare
the independent groups. The partial correlation test was used to examine correlations between parameters.
Surgical case using the new guide system
The patient was positioned supine on a traction table. After reduction maneuver, the limb was prepared
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in a standard fashion. For best assessment of the center of the femoral head and neck, a true lateral view was
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obtained to achieve alignment of the axis of the femoral neck congruent with the axis of the femoral shaft (Fig
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3a, b). A lateral view can also be used, but the true lateral view is preferred, because the lateral view does not
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necessarily reflect the real center of the head (Fig 3c, d). An image intensifier was positioned at an angle of 40°
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to the affected limb and perpendicular to the lag screw in the frontal plane. If reduction in the lateral view was
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not acceptable, the position of the proximal fragment was improved intraoperatively by anteroposterior (AP)
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pressure through an anteriorly placed rasp through the same skin incision and then a true lateral view was
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obtained.
After insertion of the nail, distal lag screw was inserted first. The position of the lag screw was adjusted
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on the AP view and the lag screw guide pin was introduced and placed on the lateral cortex. The new guide
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system was added to the targeting device with its concave side facing the patient. A guide pin was added to the
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posterior arm of the guide system and stopped on the skin (Fig 4a). The true lateral view was assessed. At this
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stage, the guide pin must be seen on the center of the femoral head (Fig 4b). If the guide pin cannot be seen on
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the center of the head, the targeting device is rotated anteriorly or posteriorly until the guide pin is seen on the
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center of the femoral head. If, in lack of experienced staff a true lateral view could not be obtained, a lateral view
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is used to place the guide pins. The arms of the guide are 15° anteverted with reference to the femoral neck.
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Thus, positioning the guide pin parallel to the femoral neck on the lateral view indicates that the lag screw guide
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pin can be introduced correctly (Fig 5a). The direction of the second (proximal) lag screw will be the same with
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the first (distal) screw. So there is no need to arrange anteversion for second screw. After appropriate placement
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of lag screw guide pins, lag screws were introduced and an initial true lateral view was obtained (Fig 5b).
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Results
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The median value of absolute deviation showed a significant difference between groups A and B (P <
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0.001). When we measured the deviation angle in all 55 cases, the values were –11° to +15° for the 27 cases in
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group A (median value of absolute deviation = 8 ± 6°); the deviation was 0° in four cases. In the 28 cases after
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introduction of the new guide system (group B), the deviation ranged from –5° to +6° (median value of absolute
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deviation = 0.5° ± 3°); the deviation was 0° in 18 cases (Table 2; Graphic 1).
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The median number of attempts to place K wires was also significantly different between groups A and
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B (P < 0.001). The total number of attempts to place lag screws was 80 for the 27 cases in group A (median, 3 ±
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2). Among them, the lag screws were placed at the first or second attempt in only four and at eight cases,
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respectively. The total number of attempts to place lag screws was 38 for the 28 cases in group B (median, 1 ±
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1). In 18 cases, lag screws were placed at the first attempt, and at the second attempt in another 10 cases (Table
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2; Fig 6). The mean operation time decreased significantly after introduction of the new guide system (P <
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0.001). The mean operation times were 54.7 ± 8.8 min in group A and 46.5 ± 7.5 min in group B (Table 2).
In group A, a positive correlation was found between different AO fracture patterns and operation time
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(r=0,470), deviation from the central axis of the femoral head (r=0,417), and attempts to place K wires(r=0,466).
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However, in group B, there was no correlation between AO fracture patterns and operation time, deviation from
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the central axis of the femoral head, or attempts to place K wires.
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Discussion
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In operative treatment of trochanteric femoral fractures, implant-related postoperative complications
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using intramedullary nails (IMNs) are still common, compared with sliding hip screws (SHS), despite their
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biomechanical superiority over SHS [8– 10]. Cutout, which is a serious complication of the surgical treatment of
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trochanteric fractures, usually requires revision surgery. The incidence of cutout after use of IMNs varies from
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1.3% to 10% in different reports [7, 11 – 13].
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Various studies have examined the optimum place for the lag screw in the femoral head and best
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predictive factors for cutout in intertrochanteric fractures. Bojan et al. [14] noted that cutout was related to three
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key factors—complex fracture types, unsatisfactory anatomical reduction, and malposition of lag screws—and
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that a combination of several factors occurred in most cutout cases. Baumgaertner et al. [ 4] noted that the tip
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apex index was the most valuable parameter for predicting lag screw cutout. In contrast, Kawaguchi et al. [11]
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used Asiatic gamma nails to treat 60 intertrochanteric fractures. Their study showed that rather than the degree of
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osteoporosis, the type of fracture, or the accuracy of the reduction, the cutout index, calculated by multiplying
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the distance of the screw tip from the subchondral bone on the AP view and distance of the screw tip from the
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central axis of the femoral head on the lateral view, was the most valuable parameter for predicting cutout.
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Nishiura et al. [7] measured deviation angles between the axis of the lag screw and the femoral head to assess the
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position of the lag screw in the femoral head. They determined that the correct placement of the lag screws had a
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deviation of less than ±5° from the central axis. The advantages of this method are that the value of the angle
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does not change with different degrees of magnification with the image intensifier and it is easy to perform. Most
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studies have indicated that failures occur when the lag screw has been placed anteriorly, posteriorly, or
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superiorly [4, 5, 15]. There is a general consensus that the lag screw should be placed centrally in the lateral plane
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and centrally [4, 5, 16] or inferiorly [2, 15] in the AP plane.
There have been several previous studies regarding how to place the lag screw appropriately in the
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femoral head. Nishiura et al. reported that to place the lag screw in the femoral head centrally, true lateral images
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had to be obtained and concluded that the targeting device had to be seen as a square in the true lateral images to
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verify accurate screw placement [7]. Park et al. investigated the pin shift phenomenon and suggested that further
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comprehensive evaluations are required [17].
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However, the criteria defined in previous studies to determine accurate positioning of the lag screw
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intraoperatively have been subjective and the screws can be placed most accurately only by experienced
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surgeons. As intertrochanteric fracture surgery is one of the most common surgical procedures performed, a
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guide system that can be used easily by any surgeon is needed. Our targeting device consists of two arms with
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angles of 15°. This device can be manufactured and adapted readily to other targeting devices and used with
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other nails that are commercially available.
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The finding of a positive correlation between the AO fracture type and the median deviation of the
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screw from the central axis of the femoral head and the median number of K wires used in the A subgroup of
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patients showed that the surgical procedure becomes more difficult with decreasing fracture stability. As the
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number of K wire entrance points increases with more unstable fractures, loss of reduction may occur, although
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anatomical reduction had been obtained previously. Repeated anterior and posterior rotation of the targeting
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device to place the K wire in the appropriate position in the sagittal plane may account for the loss of reduction.
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As a result, as the stability decreases, the number of K wire entry points and operative time increase and the K
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wires cannot be placed centrally in the lateral plane. Similarly, in group A, K wires were placed in an acceptable
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position (±5°) in only 10/27 (37%) patients.
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In the group B patients, there were no correlations between AO fracture type, median deviation of the
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screw, median number of K wire entrance points, or operative time. The new guiding system allowed placement
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of K wires without violating the lateral cortex and with minimum effort. Thus, anatomical reduction is not lost
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even in unstable fractures and K wires may be placed with maximum accuracy in the minimum amount of time.
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Excluding the two patients in the B subgroup with 6° deviation, K wires were placed accurately (±5°) in the
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lateral images in all of the other patients. This resulted in significantly shorter operation periods.
Limitations of this study include the small numbers of patients and the lack of long-term follow-up to
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evaluate the measurement method and cutout rates between the two groups. Patients that we weren't able to get a
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true lateral view were not recorded so how that effected the number of K-wire penetrations, or time, etc could
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not be discussed.
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Conclusions
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In conclusion, with the new guide system, at least we were able to insert the lag screw successfully in
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the optimal position, even in most unstable fractures and prevent loss of anatomical reduction obtained during
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surgery. The present study indicated that this new guide system allow accurate lag screw placement in the proper
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position with the minimum number of attempts.
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2- Parker MJ. Cutting-out of the dynamic hip screw related to its position. J Bone Joint Surg Br
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fractures: the prognostic value of osteoporosis. J Orthop Trauma 1993;7(5):438.
1992;74:625.
3- Wu CC, Shih CH, Lee MY, et al. Biomechanical analysis of location of lag screw of a dynamic hip
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1- Barrios C, Brostrom LA, Stark A, et al. Healing complications after internal fixation of trochanteric hip
screw in treatment of unstable intertrochanteric fracture. J Trauma 1996;41(4):699-702.
4- Baumgaertner MR, Curtin SL, Lindskog DM, et al. The value of the tip apex distance in predicting
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failure of fixation of peritrochanteric fractures of the hip. J Bone Joint Surg Am 1995;77:1058–64. 5- Kyle RF, Cabanela ME, Russell TA, et al. Fractures of the proximal part ofthe femur. Instr Course Lect
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1995;44:227–53.
6- Marsh JL, Slongo TF, Agel J, et al. Fracture and Dislocation Classification Compendium - 2007:
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Orthopaedic Trauma Association Classification, Database and Outcomes Committee. J Orthop Trauma
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2007;21 Supplement 10 pp: S1-S133
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7- Nishiura T, Nozawa M, Morio H. The new technique of precise insertion of lag screw in an operative
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treatment of trochanteric femoral fractures with a short intramedullary nail. Injury 2009;40:1077–83
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8- Bridle SH, Patel AD, Bircher M, et al. Fixation of intertrochanteric fractures of the femur: a randomised
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prospective comparison of the Gamma nail and the dynamic hip screw. J Bone Joint Surg Br
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9- Jones HW, Johnston P, Parker M. Are short femoral nails superior to the sliding hip screw? A metaanalysis of 24 studies involving 3,279 fractures. Int Orthop 2006;30(2):69–78.
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10- Parker MJ, Handoll HH. Gamma and other cephalocondylic intramedullary nails versus extramedullary
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implants for extracapsular hip fractures. Cochrane Database Syst Rev 2008;16(July (3)). CD000093.
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11- Kawaguchi S, Sawada K, Nabeta Y. Cutting-out of the lag screw after internal fixation with the Asiatic
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gamma nail. Injury 1998;29(1):47-53.
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12- Adams CI, Robinson CM, Court-Brown CM, et al. Prospective Randomized Controlled Trial of an
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Intramedullary Nail Versus Dynamic Screw and Plate for Intertrochanteric Fractures of the Femur. J
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Orthop Trauma 2000;15(6):394-400.
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13- Simmermacher RKJ, Ljungqvist J, Bail H, Hockertz T, et al. The new Proximal femoral antirotation (PFNA) in daily practice: Results of a multicentre clinical study. Injury 2008;39:932-9.
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14- Bojan A, Taglang G, Beimel C, et al. A retrospective analysis of cut out complications in 3066 patients
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treated with Gamma nails. In: The 9th Conference of the International Society for Fracture Repair in
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Bologna; 2004;p. 4–5. News AIOD.
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fractures: an evaluation of 937 patients. Int Orthop 2010;34(8):1273-6.
16- Larsson S, Friberg S, Hansson LI. Trochanteric fractures. Influence of reduction and implant position
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15- Hsueh KK, Fang CK, Chen CM, et al. Risk factors in cut-out of sliding hip screw in intertrochanteric
on impaction and complications. Clin Orthop Relat Res 1990;259:130–9. 17- Park J, Park SY, Yoon HK, Kim DY, Lee HY, Yang KH. Correction of lag screw guide pins
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inappropriately placed during intramedullary hip nailing. Injury 2008;39(10):1134-40.
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The English in this document has been checked by at least two professional editors, both native speakers of
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English. For a certificate, please see:
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http://www.textcheck.com/certificate/HH3JMe
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Figure 1. A. Trochanteric nail (TRON) B. The new guide system has two arms that are
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anteverted by 15°, with 3.0-mm K wire holes. C. The holes mounting with the new guide
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system at the superolateral end of the targeting device (red arrows). D. The targeting device
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and the new guide system used together. The guide pin, applied to the posterior arm, is in the
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same line as the drill guide sleeve.
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Figure 2. Measured deviation angles between the axis of the lag screw and the femoral head.
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A. +4° (anterior) deviation from the central axis of the femoral head. B. –9° (posterior)
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deviation from the central axis of the femoral head. C. 0° deviation from the central axis of
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the femoral head. Centrally positioned screw. D. 0° deviation from the central axis of the
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femoral head. Centrally positioned screw. TM, trochanter major.
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Figure 3. A. True lateral view. The image intensifier in inclined by approximately 20° from
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the coronal plane. B. Alignment of the axis of the femoral neck congruent with the axis of the
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femoral shaft obtained on the true lateral view. C. Lateral view of neck and head of femur. D.
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Neck and head of the femur seen anteverted on lateral view.
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Figure 4. A. New guide system added to the targeting device. A guide pin added to the
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posterior arm of the guide system and stopped on the skin. B. Guide pin on the center of the
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femoral head in the true lateral view. C. Guide pin and lag screw guide pin seen in the same
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line.
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Figure 5. A. Guide pin and neck of the femur seen parallel in the lateral view. Lag screw
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guide pin seen in the center of the femoral head. B. Initial radiograph obtained after the
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operation.
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Graphic 1. Median values of absolute deviation angles and numbers of attempts for all
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patients.
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Table 1. Preoperative Patient Data
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Table 2. İntraoperative Patient Data
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Acknowledgement: No funding has been recevied for this study. Authors thank to “Tıpsan Medikal” for
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providing the guide system which has been used in this study.
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Table 1
Table 1
Preoperative Patient Data Group B No. (%) Total No.
(%)
No. hips
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Mean age(y) 80,1±10,3
76,7±10,6
Gender(M/F)
12/15
28
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Fracture patterns
28
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11(40,7%)
10/18
14(51,9%)
18(64,3%)
AO type III
2(7,4%)
3(10,7%
11(40,7%)
7(25%)
16(59,3%)
21(75%)
22/33
5(9,1%)
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Unstable (AO type 2 and 3) 37(67.3%)
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AO type II 32(58,2%)
Stable (AO type 1) 18(32,7%)
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7(25%)
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AO type I 18(32,7%)
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83,3±9,1
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Table 2
Table 2
İntraoperative Patient Data Group A No. Median value of absolute deviation (Median±IQR*).
Group B No.
8±6
0,5±3
Stable Fractures (AO type I)
4±8
Unstable Fractures (AO type II and III)
9±5
No. 0˚ deviation
1±3 14
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0±5
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different fracture patterns (Median±IQR*)
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Median value of absolute deviation for
No. 0˚ deviation for different
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fracture patterns Stable Fractures (AO type I)
No. total attempts** Median value of attempt (Median±IQR)
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No. 1 attempt
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Unstable Fractures (AO type II and III)
3
4
1
10
80
38
3±2
1±1
4
18
2±2
1±0
3,5±3
1±1
54,7±8,8
46,5±7,5
51±7,2
45,3±11
Median value of attempt for different fracture patterns (Median±IQR)
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Stable Fractures (AO type I)
Unstable Fractures (AO type II and III)
Mean surgery duration (min.)
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Mean surgery duration for different fracture patterns (min.)
Stable Fractures (AO type I) Unstable Fractures (AO type II and III)
57,2±9
46,9±6,2
. *Inter Quartile Range **attempts to place K wire in an appropriate position in lateral view.
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Figure 5
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