- Email: [email protected]
Screening time for extra-capsular proximal femoral fracture fixation; the difference between extra-medullary and intra-medullary implant usage
Injury, Int. J. Care Injured (2004) 35, 1010—1014
Screening time for extra-capsular proximal femoral fracture fixation; the difference between extra-medullary and intra-medullary implant usage N.H. Shah*, N.P. Walton, T.A. Sudhahar, S.T. Donell Department of Trauma and Orthopaedic Surgery, Institute of Orthopaedics, Norfolk and Norwich University Hospital NHS Trust, Colney Lane, Norwich NR4, UK Accepted 10 November 2003
KEYWORDS Hip fractures; Radiation; Screening time; IMHS; DHS
Summary The aim of this study was to compare the fluoroscopic screening time used for treatment of fractures of the trochanteric region of the femur using two different implant systems. Data were collected from 277 proximal femoral fracture fixations. A dynamic hip screw (DHS) was used in 145, and an intra-medullary hip screw (IMHS) was used in 132. There was no difference between the two groups with respect to age, gender or side. Altogether, there were 42% two parts, 35% were three parts and 23% were four parts extra-capsular neck fractures. There was no statistical difference in ionising radiation exposure in closed reduction of these fractures regardless of the fracture configuration or surgical experience of the surgeon. The mean screening time to implant a DHS in two part fractures was 0.48 min, for three part fractures it was 0.45 min and for four part fractures it was 0.46 min. The mean screening time to implant IMHS was 1.02 min for two part fractures, 0.96 min for three part fractures and 1.03 min for four part fractures. These differences were statistically significant (P 0:05). ß 2003 Elsevier Ltd. All rights reserved.
Introduction The insertion of a dynamic hip screw (DHS) is a common operation for fractures of the trochanteric area. The sliding hip screw has become the implant of choice for extra-capsular fracture fixation.5 Nonetheless failures of fixation rates of up to 15%4,15 have been reported. This led to the development of intra-medullary fixation devices. The intra-medullary hip screw (IMHS) (Smith & Nephew, Richards, Memphis, TN, USA) was designed for the *Corresponding author. Present address: 50 Butterfly Meadows, East Riding of Yorkshire, Beverley HU17 9GA, UK. Tel.: þ44-7956-887078. E-mail address: [email protected] (N.H. Shah).
treatment of extra-capsular fractures of the hip and consists of a lag screw, which passes through an intra-medullary nail. The standard IMHS consists of 21 cm-long intra-medullary rod and a telescoping sliding screw. The nail has a valgus angle of 48 proximally to allow insertion through the greater trochanter. The nail can be locked distally with either one or two 4.5 mm screws. Shaft diameters available are 10, 12, 14 and 16 mm. In this study all patients had an IMHS with a 12 mm diameter and the distal locking was performed using only one screw. A 1358 neck shaft angle was usually used, although 1308 options were available. The IMHS has a sliding screw and sleeve geometry that is similar to the screw and barrel of a dynamic hip screw. Theoretical mechanical advantages of an intra-medullary
0020–1383/$ — see front matter ß 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2003.11.012
The difference between extra-medullary and intra-medullary implant usage
device are reduction of the lever arm across the device and medialising the moment of inertia. Biological advantages of semi-percutaneous insertion technique include less soft tissue disturbance around the fracture site. Intra-operative fluoroscopy is necessary to aid the reduction of extra-capsular fractures of the femur and to guide insertion of the implants. The surgeon is confronted with increased exposure to radiation because repositioning is influenced by fluoroscopic images. There are many publications on the relative doses of ionising radiation that trauma surgeons and other theatre personnel are exposed to in various operations.6,14 Ionising radiation is associated with numerous pathological processes including infertility, cataracts and increased rates of carcinoma of the thyroid.6 Studies have been published which suggest that radiation exposure will increase if, the surgeon performing the surgery is inexperienced,8 more complex fractures are being fixed, intra-medullary fixation is used for simple fractures.1 Equally, the use of a laser pointer on the image intensifier3 and surgical seniority8 has been found to reduce radiation exposure. This study compares the fluoroscopic screening time used for the standard dynamic hip screw and the intra-medullary hip screw.
Methods and materials The study took place in a busy university hospital serving a population of around 500,000 and was performed in two stages; retrospective data collection and then a prospective study. All retrospective cases of proximal femoral fracture were selected from the theatre register in the year between February 2000 and March 2001. For each case, we collected the clinical records, and theatre records. Data from radiographer’s log Xrays were retrieved to assess age and gender of the patient, type of the fracture, implant used, the settings of the image intensifier used during operation, fluoroscopy screening time and the grade of surgeon undertaking the operation. Patients with pathological fractures, subtrochanteric fractures, reverse oblique fractures and those which required derotation screws with their implants were excluded from the study. Subsequently, 235 cases out of 280 were found with complete data. The type of fracture was classified using a modification of Jensen’s classification.11 This divides the fractures into two, three or four part. The IMHS was used for more complex and unstable three and four part fractures, while the DHS was used for stable two part fractures. The surgeons who
1011
performed both the procedures were either consultants or trainees with a minimum of 3 years of orthopaedic experience and around 1 year of experience with IMHS. The results recorded were then statistically tested with a Mann—Whitney test. The null hypothesis was rejected where P was <0.05. The data regarding the screening time was collected from the radiographer’s log. It recorded the kilovolts, milli-amperes and the number of minutes of screening. A single image intensifier (model BV25; Phillips Medical) was used throughout the study period. This model has a memory, which continues to display the image on the screen after the beam has been turned off. The intensifier controlled the number of kilovolts and milli-amperes automatically. The number of minutes that the fluoroscope had been used was read directly from the machine. It represented the sum of real time fluoroscopy and pulsed image intensification. The timer was always set at zero at the start of each procedure. A prospective study using the same method was then performed over 5 month’s period in an attempt to exclude possible bias in implant selection relative to fracture pattern. In this part of the study, the screening time was divided into fracture reduction time and implant insertion time. Forty-two patients were included in the second part of the study. Otherwise the same data was recorded. Implant selection was based on surgeon’s preference and instrument availability.
Results In the retrospective part of the study, the mean age of patients was 83.5 years (36—100 years) with the mean age for DHS being 84 years and the mean age for IMHS being 82.8 years. Seventy-one percent were female and 29% were male. Forty-two percent were two part, 35% were three part and 23% were four part fractures. Two-hundred and thirty five patients were included; DHS was used in 122 and IMHS in 113. Seniority of the surgeon and complexity of the fractures are presented in Table 1. In the prospective part of the study 42 patients were included, 23 DHS and 19 IMHS. Seventy-three percent were female and 27% were male. The mean age for the whole prospective group was 80 years (21—100 years), for the DHS set it was 81.5 years and for the IMHS set it was 78.6 years. Seniority of the surgeons and complexity of the fractures are presented in Table 2. In the retrospective part of the study, there was no significant difference in the screening time for
1012
Table 1
N.H. Shah et al.
Retrospective data No. of cases Total
Two part #
Three part #
Four part #
84 38 74 39
61 27 8 2
21 10 32 20
2 1 34 17
235
98
83
54
DHS by SpR DHS by Cons IMHS by Spr IMHS by Cons Total
Table 2
Prospective data No. of cases
DHS by SpR DHS by Cons IMHS by Spr IMHS by Cons
17 6 12 7
Total
42
Table 3
Two part #
Three part #
Four part #
13 6 0 1
4 0 8 1
0 0 4 5
Screening time in retrospective data Screening time
DHS by SpR DHS by Cons IMHS by Spr IMHS by Cons
Two part #
Three part #
Four part #
0.48 (0.1—1.15) 0.53 (0.1—1.6) 1.11 (0.3—2.0) 0.8 (0.5—1.1)
0.47 0.38 1.01 0.82
0.55 (0.5—0.6) 0.3 1.01 (0.3—3.6) 1.08 (0.2—3.5)
the 122 DHS between the seniority of the surgeons or the complexity of the fracture. Of the total 113 IMHS reviewed retrospectively, there was no significant difference found between the surgical experience of the surgeon or the complexity of the fracture against the screening time used to implant IMHS (P ¼ 0:68) (Table 3). However there was significant difference in the screening time between DHS and IMHS irrespective of the complexity of the fracture or the seniority of the surgeons (P 0:05). Table 4
(0.29—1.1) (0.2—0.5) (0.3—2.9) (0.2—2.5)
In the prospective part of the study, the fracture reduction time was significantly less than the implant insertion time; irrespective of the implant, complexity of the fracture or the seniority of the surgeon (Table 4). Therefore, the initial assumption that complex fractures were difficult to reduce and hence, more complex fractures require more screening was not supported. Nevertheless, there was a significant difference between the screening time used for the DHS and IMHS insertion (P 0:05). A significant difference was observed (P 0:05)
Screening time in prospective data Reduction time
DHS by SpR DHS by Cons IMHS by Spr IMHS by Cons
Insertion time
Two part #
Three part #
Four part #
Two part #
Three part #
Four part #
0.08 (0.01—0.15) 0.07 (0.05—0.1) 0 0.09
0.14 (0.14—1.5) 0 0.09 (0.09—0.1) 0.09
0 0 0.08 (0.05—0.11) 0.1 (0.07—0.15)
0.38 (0.08—0.5) 0.24 (0.03—0.4) 0 0.9
0.41 (0.4—0.43) 0 1.01 (0.56—1.3) 0.8
0 0 1.05 (0.82—1.28) 0.46 (0.41—0.5)
The difference between extra-medullary and intra-medullary implant usage
Table 5
Mean screening times for DHS and IMHS
Two part # Three part # Four part #
DHS
IMHS
0.48 (n ¼ 107) 0.45 (n ¼ 35) 0.46 (n ¼ 3)
1.02 (n ¼ 11) 0.96 (n ¼ 61) 1.03 (n ¼ 60)
between the mean screening times for the DHS and IMHS in the total 277 patients (Table 5).
Discussion Studies have shown that the radiation exposure to the orthopaedic surgeon is well below the permissible dose for occupational exposure.6,14 Giachino and Cheng7 measured the radiation scatter that the orthopaedic surgeon was exposed to during pinning of the neck of the femur and found that when the surgeon moved at least 18 in. (46 cm) from the greater trochanter the exposure to radiation was greatly reduced. However, since the long-term effect of radiation is unknown, the dose of radiation exposure to the surgeon and theatre staff should be kept to a minimum. The treatment of unstable intertrochanteric fractures is still controversial.12 Baumgaertner et al. noticed that in their study that 23% less time was required to insert IMHS compared with the placement of sliding hip screw in unstable fractures, but in stable fractures, IMHS insertion required 70% more fluoroscopy time than compression hip screw insertion.2 Studies have been undertaken to compare the treatment of proximal femoral fractures with an extra-medullary and intra-medullary implants.1,10,13 These conclude that the IMHS is an alternative treatment for comminuted fractures with subtrochanteric extension or reverse obliquity because of decreased shortening of the limb and the possibility of early weight bearing.1 They also conclude that fixation of stable intertrochanteric fractures with an IMHS cannot be recommended.1,9 Hardy et al.9 noticed that the operating time required to insert the IMHS was significantly greater when using the sliding hip screw. They also recommend the use of one distal locking screw rather than two in fractures where rotational instability and subsidence are likely to be a problem. Our practice adheres to these principles. Giannoudis et al.8 state that radiation and screening time were proportional to the difficulty of the fracture with greater times occurring with four part fractures than two part fractures regardless of grade of surgeon.
1013
During the study, we concentrated on the radiation exposure and seniority of the surgeon when comparing the screening time. In both parts of our study, screening times for DHS and IMHS insertion were significantly different, with the IMHS taking more time. This result was independent of comminution of fracture or grade of surgeon. As the retrospective study could not differentiate the time taken for actual insertion of the implant, the prospective part was done to differentiate the screening time for reduction of fracture and for implant insertion. The prospective and retrospective parts of the study reached the same conclusion. It was not possible to ascertain whether IMHS insertion requires longer screening when used in complex fracture patterns during this study. The fact that screening time for IMHS insertion was longer could be because both the nail and lag screw needs to be screened during their insertion, whereas only the screw of the DHS has to be inserted under radiographic control. Inexperience in inserting the IMHS relative to the DHS may be a source of bias. Therefore, this study does support the use of one implant design over another. However, the extended screening times required when implanting the IMHS should be considered when complex fracture patterns require fixation.
Acknowledgements We are grateful to Mr. J.S. Albert, Consultant Orthopaedic Surgeon at Norfolk and Norwich University Hospital for his help and critic during the preparation of this study.
References 1. Baumgaertner MR, Curtin SL, Lindskog DM. The value of tip apex distance in predicting failure of peritrochanteric fracture fixation. J Bone Joint Surg 1995;77-A:1058—64. 2. Baumgaertner MR, Curtin SL, Lindskog DM. Intra-medullary versus extra-medullary fixation for the treatment of intertrochanteric hip fractures. Clin Orthop 1998;348: 87—94. 3. Conn KS, Hallett JP. A simple laser guide to reduce the screening time during the insertion of dynamic hip screws. Injury 1998;29(7):539—41. 4. Davis TRC, Sher JL, Horsman A, et al. Intertrochanteric femoral fractures: mechanical failure after internal fixation. J Bone Joint Surg 1990;72-B:26—31. 5. Doppelt SH. The sliding compression screw–—today’s best answer for stabilisation of intertrochanteric hip fractures. Clin Orthop 1980;11:507—23. 6. Fuchs M, Schmid A, Eiteljorge T, Modler M, et al. Exposure of the surgeon to the radiation during surgery. Int Orthop 1998;22:153—6.
1014
7. Giachino AA, Cheng M. Irradiation of the surgeons during pinning of femoral fractures. J Bone Joint Surg 1980;62B(2):227—9. 8. Giannoudis PV, McGuigan J, Shaw DL. Ionising radiation during internal fixation of extra-capsular neck of femur fractures. Injury 1998;29(6):469—72. 9. Hardy DCR, Descamps PY, Krallis P, et al. Use of an intramedullary hip-screw compared with a compression hip screw with a plate for intertrochanteric femoral fractures. J Bone Joint Surg 1998;80-A(5):618—30. 10. Harrington P, Nihal A, Singhania AK, Howell FR. Intramedullary hip screw versus sliding hip screw for unstable intertrochanteric femoral fractures in the elderly. Injury 2002;33:23—8.
N.H. Shah et al.
11. Jensen JS. Classification of trochanteric fractures. Acta Orthop Scand 1980;51:803—10. 12. Parker MJ, Handoll HH. Gamma and other cephalocondylic intra-medullary implants for extra-capsular hip fractures. Cocharane Database Syst Rev 2000;2:CD000093. 13. Parker MJ, Pryor GA. Gamma versus DHS nailing for extracapsular femoral fractures. Meta analysis of ten randomised trials. Int Orthop 1996;20:163—8. 14. Sanders R, Koval KJ, DiPasquale T, et al. Exposure of the orthopaedic surgeon to radiation. J Bone Joint Surg 1993;75A(3):326—30. 15. Wolfgang GL, Bryant MH, O’Neill JP. Treatment of intertrochanteric fracture of the femur using sliding screw plate fixation. Clin Orthop 1982;163:148—58.
Screening time for extra-capsular proximal femoral fracture fixation; the difference between extra-medullary and intra-medullary implant usage N.H. Shah*, N.P. Walton, T.A. Sudhahar, S.T. Donell Department of Trauma and Orthopaedic Surgery, Institute of Orthopaedics, Norfolk and Norwich University Hospital NHS Trust, Colney Lane, Norwich NR4, UK Accepted 10 November 2003
KEYWORDS Hip fractures; Radiation; Screening time; IMHS; DHS
Summary The aim of this study was to compare the fluoroscopic screening time used for treatment of fractures of the trochanteric region of the femur using two different implant systems. Data were collected from 277 proximal femoral fracture fixations. A dynamic hip screw (DHS) was used in 145, and an intra-medullary hip screw (IMHS) was used in 132. There was no difference between the two groups with respect to age, gender or side. Altogether, there were 42% two parts, 35% were three parts and 23% were four parts extra-capsular neck fractures. There was no statistical difference in ionising radiation exposure in closed reduction of these fractures regardless of the fracture configuration or surgical experience of the surgeon. The mean screening time to implant a DHS in two part fractures was 0.48 min, for three part fractures it was 0.45 min and for four part fractures it was 0.46 min. The mean screening time to implant IMHS was 1.02 min for two part fractures, 0.96 min for three part fractures and 1.03 min for four part fractures. These differences were statistically significant (P 0:05). ß 2003 Elsevier Ltd. All rights reserved.
Introduction The insertion of a dynamic hip screw (DHS) is a common operation for fractures of the trochanteric area. The sliding hip screw has become the implant of choice for extra-capsular fracture fixation.5 Nonetheless failures of fixation rates of up to 15%4,15 have been reported. This led to the development of intra-medullary fixation devices. The intra-medullary hip screw (IMHS) (Smith & Nephew, Richards, Memphis, TN, USA) was designed for the *Corresponding author. Present address: 50 Butterfly Meadows, East Riding of Yorkshire, Beverley HU17 9GA, UK. Tel.: þ44-7956-887078. E-mail address: [email protected] (N.H. Shah).
treatment of extra-capsular fractures of the hip and consists of a lag screw, which passes through an intra-medullary nail. The standard IMHS consists of 21 cm-long intra-medullary rod and a telescoping sliding screw. The nail has a valgus angle of 48 proximally to allow insertion through the greater trochanter. The nail can be locked distally with either one or two 4.5 mm screws. Shaft diameters available are 10, 12, 14 and 16 mm. In this study all patients had an IMHS with a 12 mm diameter and the distal locking was performed using only one screw. A 1358 neck shaft angle was usually used, although 1308 options were available. The IMHS has a sliding screw and sleeve geometry that is similar to the screw and barrel of a dynamic hip screw. Theoretical mechanical advantages of an intra-medullary
0020–1383/$ — see front matter ß 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2003.11.012
The difference between extra-medullary and intra-medullary implant usage
device are reduction of the lever arm across the device and medialising the moment of inertia. Biological advantages of semi-percutaneous insertion technique include less soft tissue disturbance around the fracture site. Intra-operative fluoroscopy is necessary to aid the reduction of extra-capsular fractures of the femur and to guide insertion of the implants. The surgeon is confronted with increased exposure to radiation because repositioning is influenced by fluoroscopic images. There are many publications on the relative doses of ionising radiation that trauma surgeons and other theatre personnel are exposed to in various operations.6,14 Ionising radiation is associated with numerous pathological processes including infertility, cataracts and increased rates of carcinoma of the thyroid.6 Studies have been published which suggest that radiation exposure will increase if, the surgeon performing the surgery is inexperienced,8 more complex fractures are being fixed, intra-medullary fixation is used for simple fractures.1 Equally, the use of a laser pointer on the image intensifier3 and surgical seniority8 has been found to reduce radiation exposure. This study compares the fluoroscopic screening time used for the standard dynamic hip screw and the intra-medullary hip screw.
Methods and materials The study took place in a busy university hospital serving a population of around 500,000 and was performed in two stages; retrospective data collection and then a prospective study. All retrospective cases of proximal femoral fracture were selected from the theatre register in the year between February 2000 and March 2001. For each case, we collected the clinical records, and theatre records. Data from radiographer’s log Xrays were retrieved to assess age and gender of the patient, type of the fracture, implant used, the settings of the image intensifier used during operation, fluoroscopy screening time and the grade of surgeon undertaking the operation. Patients with pathological fractures, subtrochanteric fractures, reverse oblique fractures and those which required derotation screws with their implants were excluded from the study. Subsequently, 235 cases out of 280 were found with complete data. The type of fracture was classified using a modification of Jensen’s classification.11 This divides the fractures into two, three or four part. The IMHS was used for more complex and unstable three and four part fractures, while the DHS was used for stable two part fractures. The surgeons who
1011
performed both the procedures were either consultants or trainees with a minimum of 3 years of orthopaedic experience and around 1 year of experience with IMHS. The results recorded were then statistically tested with a Mann—Whitney test. The null hypothesis was rejected where P was <0.05. The data regarding the screening time was collected from the radiographer’s log. It recorded the kilovolts, milli-amperes and the number of minutes of screening. A single image intensifier (model BV25; Phillips Medical) was used throughout the study period. This model has a memory, which continues to display the image on the screen after the beam has been turned off. The intensifier controlled the number of kilovolts and milli-amperes automatically. The number of minutes that the fluoroscope had been used was read directly from the machine. It represented the sum of real time fluoroscopy and pulsed image intensification. The timer was always set at zero at the start of each procedure. A prospective study using the same method was then performed over 5 month’s period in an attempt to exclude possible bias in implant selection relative to fracture pattern. In this part of the study, the screening time was divided into fracture reduction time and implant insertion time. Forty-two patients were included in the second part of the study. Otherwise the same data was recorded. Implant selection was based on surgeon’s preference and instrument availability.
Results In the retrospective part of the study, the mean age of patients was 83.5 years (36—100 years) with the mean age for DHS being 84 years and the mean age for IMHS being 82.8 years. Seventy-one percent were female and 29% were male. Forty-two percent were two part, 35% were three part and 23% were four part fractures. Two-hundred and thirty five patients were included; DHS was used in 122 and IMHS in 113. Seniority of the surgeon and complexity of the fractures are presented in Table 1. In the prospective part of the study 42 patients were included, 23 DHS and 19 IMHS. Seventy-three percent were female and 27% were male. The mean age for the whole prospective group was 80 years (21—100 years), for the DHS set it was 81.5 years and for the IMHS set it was 78.6 years. Seniority of the surgeons and complexity of the fractures are presented in Table 2. In the retrospective part of the study, there was no significant difference in the screening time for
1012
Table 1
N.H. Shah et al.
Retrospective data No. of cases Total
Two part #
Three part #
Four part #
84 38 74 39
61 27 8 2
21 10 32 20
2 1 34 17
235
98
83
54
DHS by SpR DHS by Cons IMHS by Spr IMHS by Cons Total
Table 2
Prospective data No. of cases
DHS by SpR DHS by Cons IMHS by Spr IMHS by Cons
17 6 12 7
Total
42
Table 3
Two part #
Three part #
Four part #
13 6 0 1
4 0 8 1
0 0 4 5
Screening time in retrospective data Screening time
DHS by SpR DHS by Cons IMHS by Spr IMHS by Cons
Two part #
Three part #
Four part #
0.48 (0.1—1.15) 0.53 (0.1—1.6) 1.11 (0.3—2.0) 0.8 (0.5—1.1)
0.47 0.38 1.01 0.82
0.55 (0.5—0.6) 0.3 1.01 (0.3—3.6) 1.08 (0.2—3.5)
the 122 DHS between the seniority of the surgeons or the complexity of the fracture. Of the total 113 IMHS reviewed retrospectively, there was no significant difference found between the surgical experience of the surgeon or the complexity of the fracture against the screening time used to implant IMHS (P ¼ 0:68) (Table 3). However there was significant difference in the screening time between DHS and IMHS irrespective of the complexity of the fracture or the seniority of the surgeons (P 0:05). Table 4
(0.29—1.1) (0.2—0.5) (0.3—2.9) (0.2—2.5)
In the prospective part of the study, the fracture reduction time was significantly less than the implant insertion time; irrespective of the implant, complexity of the fracture or the seniority of the surgeon (Table 4). Therefore, the initial assumption that complex fractures were difficult to reduce and hence, more complex fractures require more screening was not supported. Nevertheless, there was a significant difference between the screening time used for the DHS and IMHS insertion (P 0:05). A significant difference was observed (P 0:05)
Screening time in prospective data Reduction time
DHS by SpR DHS by Cons IMHS by Spr IMHS by Cons
Insertion time
Two part #
Three part #
Four part #
Two part #
Three part #
Four part #
0.08 (0.01—0.15) 0.07 (0.05—0.1) 0 0.09
0.14 (0.14—1.5) 0 0.09 (0.09—0.1) 0.09
0 0 0.08 (0.05—0.11) 0.1 (0.07—0.15)
0.38 (0.08—0.5) 0.24 (0.03—0.4) 0 0.9
0.41 (0.4—0.43) 0 1.01 (0.56—1.3) 0.8
0 0 1.05 (0.82—1.28) 0.46 (0.41—0.5)
The difference between extra-medullary and intra-medullary implant usage
Table 5
Mean screening times for DHS and IMHS
Two part # Three part # Four part #
DHS
IMHS
0.48 (n ¼ 107) 0.45 (n ¼ 35) 0.46 (n ¼ 3)
1.02 (n ¼ 11) 0.96 (n ¼ 61) 1.03 (n ¼ 60)
between the mean screening times for the DHS and IMHS in the total 277 patients (Table 5).
Discussion Studies have shown that the radiation exposure to the orthopaedic surgeon is well below the permissible dose for occupational exposure.6,14 Giachino and Cheng7 measured the radiation scatter that the orthopaedic surgeon was exposed to during pinning of the neck of the femur and found that when the surgeon moved at least 18 in. (46 cm) from the greater trochanter the exposure to radiation was greatly reduced. However, since the long-term effect of radiation is unknown, the dose of radiation exposure to the surgeon and theatre staff should be kept to a minimum. The treatment of unstable intertrochanteric fractures is still controversial.12 Baumgaertner et al. noticed that in their study that 23% less time was required to insert IMHS compared with the placement of sliding hip screw in unstable fractures, but in stable fractures, IMHS insertion required 70% more fluoroscopy time than compression hip screw insertion.2 Studies have been undertaken to compare the treatment of proximal femoral fractures with an extra-medullary and intra-medullary implants.1,10,13 These conclude that the IMHS is an alternative treatment for comminuted fractures with subtrochanteric extension or reverse obliquity because of decreased shortening of the limb and the possibility of early weight bearing.1 They also conclude that fixation of stable intertrochanteric fractures with an IMHS cannot be recommended.1,9 Hardy et al.9 noticed that the operating time required to insert the IMHS was significantly greater when using the sliding hip screw. They also recommend the use of one distal locking screw rather than two in fractures where rotational instability and subsidence are likely to be a problem. Our practice adheres to these principles. Giannoudis et al.8 state that radiation and screening time were proportional to the difficulty of the fracture with greater times occurring with four part fractures than two part fractures regardless of grade of surgeon.
1013
During the study, we concentrated on the radiation exposure and seniority of the surgeon when comparing the screening time. In both parts of our study, screening times for DHS and IMHS insertion were significantly different, with the IMHS taking more time. This result was independent of comminution of fracture or grade of surgeon. As the retrospective study could not differentiate the time taken for actual insertion of the implant, the prospective part was done to differentiate the screening time for reduction of fracture and for implant insertion. The prospective and retrospective parts of the study reached the same conclusion. It was not possible to ascertain whether IMHS insertion requires longer screening when used in complex fracture patterns during this study. The fact that screening time for IMHS insertion was longer could be because both the nail and lag screw needs to be screened during their insertion, whereas only the screw of the DHS has to be inserted under radiographic control. Inexperience in inserting the IMHS relative to the DHS may be a source of bias. Therefore, this study does support the use of one implant design over another. However, the extended screening times required when implanting the IMHS should be considered when complex fracture patterns require fixation.
Acknowledgements We are grateful to Mr. J.S. Albert, Consultant Orthopaedic Surgeon at Norfolk and Norwich University Hospital for his help and critic during the preparation of this study.
References 1. Baumgaertner MR, Curtin SL, Lindskog DM. The value of tip apex distance in predicting failure of peritrochanteric fracture fixation. J Bone Joint Surg 1995;77-A:1058—64. 2. Baumgaertner MR, Curtin SL, Lindskog DM. Intra-medullary versus extra-medullary fixation for the treatment of intertrochanteric hip fractures. Clin Orthop 1998;348: 87—94. 3. Conn KS, Hallett JP. A simple laser guide to reduce the screening time during the insertion of dynamic hip screws. Injury 1998;29(7):539—41. 4. Davis TRC, Sher JL, Horsman A, et al. Intertrochanteric femoral fractures: mechanical failure after internal fixation. J Bone Joint Surg 1990;72-B:26—31. 5. Doppelt SH. The sliding compression screw–—today’s best answer for stabilisation of intertrochanteric hip fractures. Clin Orthop 1980;11:507—23. 6. Fuchs M, Schmid A, Eiteljorge T, Modler M, et al. Exposure of the surgeon to the radiation during surgery. Int Orthop 1998;22:153—6.
1014
7. Giachino AA, Cheng M. Irradiation of the surgeons during pinning of femoral fractures. J Bone Joint Surg 1980;62B(2):227—9. 8. Giannoudis PV, McGuigan J, Shaw DL. Ionising radiation during internal fixation of extra-capsular neck of femur fractures. Injury 1998;29(6):469—72. 9. Hardy DCR, Descamps PY, Krallis P, et al. Use of an intramedullary hip-screw compared with a compression hip screw with a plate for intertrochanteric femoral fractures. J Bone Joint Surg 1998;80-A(5):618—30. 10. Harrington P, Nihal A, Singhania AK, Howell FR. Intramedullary hip screw versus sliding hip screw for unstable intertrochanteric femoral fractures in the elderly. Injury 2002;33:23—8.
N.H. Shah et al.
11. Jensen JS. Classification of trochanteric fractures. Acta Orthop Scand 1980;51:803—10. 12. Parker MJ, Handoll HH. Gamma and other cephalocondylic intra-medullary implants for extra-capsular hip fractures. Cocharane Database Syst Rev 2000;2:CD000093. 13. Parker MJ, Pryor GA. Gamma versus DHS nailing for extracapsular femoral fractures. Meta analysis of ten randomised trials. Int Orthop 1996;20:163—8. 14. Sanders R, Koval KJ, DiPasquale T, et al. Exposure of the orthopaedic surgeon to radiation. J Bone Joint Surg 1993;75A(3):326—30. 15. Wolfgang GL, Bryant MH, O’Neill JP. Treatment of intertrochanteric fracture of the femur using sliding screw plate fixation. Clin Orthop 1982;163:148—58.