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Second-generation cephalomedullary nails in the treatment of reverse obliquity intertrochanteric fractures of the proximal femur
Injury, Int. J. Care Injured (2004) 35, 179—183
Second-generation cephalomedullary nails in the treatment of reverse obliquity intertrochanteric fractures of the proximal femur ¨rvinen Seppo E. Honkonen*, Kimmo Vihtonen, Markku J. Ja Department of Surgery, Division of Orthopaedics and Traumatology, University Hospital of Tampere and Medical School, University of Tampere, P.O. Box 2000, FIN-33521, Tampere, Finland Accepted 17 May 2003
KEYWORDS Reverse obliquity intertrochanteric fracture; Cephalomedullary nailing
Summary Since 1996, in Tampere University Hospital, a second-generation cephalomedullary nail (CMN) has been the implant of first choice in reverse obliquity fractures of the proximal femur. Between 1996 and 1999 we treated 77 such fractures, of which 72 were fixed with the CMN. There were six re-operations (8.3%). An anatomic or nearly anatomic reduction and a properly placed implant were found in 47 cases with one failure. An unacceptable postoperative radiological result was seen in 25 cases resulting in five re-operations (P ¼ 0:029). In 12 of 14 open procedures a cable was added to stabilise the greater trochanter and none failed. Four of five fractures fixed with the sliding hip screw failed. Our results using the CMN in reverse obliquity intertrochanteric fractures compares favourably to the results in earlier reports where extramedullary implants are used. ß 2003 Elsevier Ltd. All rights reserved.
Introduction In the literature on the treatment of extracapsular fractures of the proximal femur, reverse obliquity intertrochanteric fractures (type 31.A3 according to the Orthopaedic Trauma Association classification6) are often ignored, or obviously classified into ‘‘unstable’’ intertrochanteric or subtrochanteric fractures. Biomechanically they differ from other intertrochanteric fractures, because the main fracture line runs from distal—lateral to proximal—medial (below the greater trochanter to the lesser trochanter) and almost parallel with the loading force. There is only one study that addresses the results of treatment of this particular fracture *Corresponding author. Tel.: þ358-3-2474612; fax: þ358-3-2474358. E-mail address: [email protected] (S.E. Honkonen).
pattern, suggesting that the fracture is not reliably treated by conventional extramedullary implants.3 We have routinely used second-generation cephalomedullary nails (CMN) in all types of extracapsular fractures of the proximal femur for 10 years. Increasing experience in indications and in technical performance led us to revise our treatment protocol so that since 1996 the CMN has been the first choice implant in the treatment of reverse obliquity intertrochanteric fractures. The purpose of this retrospective study is to analyse the results of the intramedullary fixation in these challenging fractures.
Patients and methods According to the computerised patient register of Tampere University Hospital, by using the codes S72.1 and S72.2 of the International Statistical
0020–1383/$ — see front matter ß 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0020-1383(03)00208-0
180
Classification of Diseases version 10 (ICD-10), 327 patients were treated for intertrochanteric or subtrochanteric fracture between January 1996 and December 1999. After approval from the Ethical Committee of Tampere University Hospital, clinical records and radiographs that had been made at the time of the injury or immediately postoperatively for these patients were reviewed, and a reverse obliquity fracture pattern (type 31.A3 according to the Orthopaedic Trauma Association6) was identified in 77 patients. According to the treatment protocol of our clinic, cephalomedullary nailing was the preferred method in this particular fracture type. The patients were operated on within three days of admission by one of several orthopaedic surgeons or residents in training. Mini-invasive reduction and nailing was always attempted, but keeping in mind the importance of good reduction, an open procedure was highly recommended. At the start of the study the Standard Gamma Nail (SGN, Stryker-Howmedica) and the Long Gamma Nail (LGN, StrykerHowmedica) were in use. Later the Trochanteric Gamma Nail (TGN, Stryker-Howmedica) and the Proximal Femoral Nail (PFN, Stratec Medical) were available as well. The surgeon performing the operation was free to choose the implant. The medullary canal of the femur was reamed 2—3 mm wider than the diameter of the nail. In open procedures, when it was evident that the implant could not stabilise the greater trochanter, a cable (Dall-Miles, Stryker-Howmedica) was mounted using a special cannulated hook to secure reduction and stability. One or two distal locking screws were used routinely. No primary bone grafting was performed. From the first postoperative day, if possible, the patients were encouraged to walk with a rollator or crutches allowing half to full weight bearing. Preand postoperative radiographs were available in all cases. The reduction was regarded as acceptable if there was no varus malalignment of the proximal fragment or if there was less than 10 mm translation between the main fragments. The acceptable position of the tip of the lag screw was in the lower part of the femoral head in the AP-view and in the central third in the lateral view and the distance from the articular surface less than 10 mm. The follow-up was arranged together with our outpatient policlinic and the health centres responsible for aftercare and rehabilitation. When implant or fracture complication occurred or was suspected, the radiographs were sent to us for analysis. Altogether 42 cases were in active follow-up on average 19 weeks (3—52 weeks). The radiographs were checked by one surgeon (SEH). All re-operations were performed in our trauma unit. The primary outcome measure was fixation failure needing re-operation.
S.E. Honkonen et al.
Cross-tabulations were analysed using Fisher’s exact test. The computation was carried out using StatXact for Windows Software (version 4).
Results Of the 77 reverse obliquity intertrochanteric fractures, 72 were fixed with the CMN. There were 48 women, with an average age of 77.6 years (range 44—96) and 24 men, with an average age of 64.0 years (range 32—92). Ninety-six percent of the fractures were caused by simple falling indicating osteoporotic bone quality of the patients. Six of the 72 cephalomedullary nailings (8.3%) failed and resulted in major revision. Three of 44 simple fracture patterns and 3 of 28 multifragmentary fractures were revised (P ¼ 0:677). A minimally invasive procedure was performed in 58 fractures, of which, in a retrospective evaluation, 21 were poorly reduced and/or fixed with a non-ideally placed implant. Four resulted in re-operation, while of the remaining 37 fractures with anatomical reduction and with an ideally placed implant there was only one re-operation (P ¼ 0:076). An open procedure was performed in 14 cases leading to one failure, in which the fracture reduction had remained poor. In 12 of the open procedures a cable was added to stabilise the greater trochanter and none of these failed. Altogether, an acceptable radiological postoperative result was found in 47 cases leading to one re-operation. An unacceptable radiological result was seen in 25 cases leading to five re-operations (P ¼ 0:029). The eventual outcome of each intramedullary implant is seen in Table 1. The failure mode was collapse of the fracture and cut-out of the lag screw in five cases and non-union in one case. Minor procedures included one dynamisation of the SGN because of delayed union, and three removals of the antirotation screw using the PFN. In the study group, there was no peri-implant fractures needing revision. Only one split of the distal femoral metaphysis occurred using the LGN. We checked all the patients with extracapsular fractures of the proximal femur (327 patients) and found four shaft fractures in 123 standard gamma nailings (3.3%). Eighty of them were distally locked leading to one re-fracture, while there were three re-fractures in the remaining 43 cases without distal locking (P ¼ 0:122). Respectively, all 71 PFNs were used with distal locking leading to one re-fracture. Thirteen patients died within 3 months of the accident. None of them were known to have complications related to the implant. There were no deep infections in the series.
Second-generation cephalomedullary nails
Table 1
181
The eventual outcome of each implant
Standard gamma nail Trochanteric gamma nail Long gamma nail Proximal femoral nail All
Number
Good reduction and properly placed implant
Re-operation
28 4 4 36 72
20 (71.4%) 3 1 24 (66.7%) 48 (66.7%)
0 1 0 5 6 (8.3%)
In the remaining five reverse obliquity fractures, against our treatment protocol, a sliding hip screw (SHS) was used and four of them failed because of collapse of the fracture and/or cut-out of the lag screw.
Discussion Reverse obliquity fractures of the intertrochanteric region of the femur account for 5% of all inter- and subtrochanteric fractures.3 Our high percentage (23%) is explained by the fact that we have centralised the most difficult fractures of the proximal femur in one trauma unit. A hallmark of this very unstable fracture type is a horizontal or reversed fracture line starting laterally below the greater trochanter. The biomechanics of the SHS leads the fracture fragments to separate rather than compress resulting in an unacceptably high rate of failures. Rokito et al. concluded that the SHS might not be the implant of choice for reverse obliquity fractures of the intertrochanteric region.8 In our series, four of five cases fixed with the SHS had to be
revised. In two other reports the failure rate has been 24 and 56%.3,4 Babst et al. reported that addition of a trochanteric blocking plate to the SHS could effectively support the unstable greater trochanter and prevent rotation and impaction of the head—neck fragment.2 The lowest failure rate (20%) has been reported using the blade-plate or the dynamic condylar screw.3 Second-generation cephalomedullary nails have been in use more than 10 years, but clear indications for their use still are unknown. In pertrochanteric fractures, where the main fracture line is perpendicular to the loading forces, clinical results of the SHS still seem to be better.1,7 In the reverse obliquity intertrochanteric fracture the CMN theoretically provides better stability, because the leverarm is relatively short and the upper part of the intramedullary nail leans against the proximal fragment preventing medial sliding of the distal fragment (Fig. 1). In our patients, the overall failure rate of 8.3% compares favourably to the failure rate found in extramedullary fixations. Though the rate in achieving anatomic reduction and ideal placement of the implant did not differ using either the SGN or
Figure 1 No varus malalignment of the proximal fragment, well reduced medial cortices and ideally placed implant effectively prevent the medial translation of the shaft (left: preoperative, middle: postoperative, right: ossified).
182
S.E. Honkonen et al.
Figure 2 Reduction needed open procedure and a cable was added to improve fixation, but too lateral entry point of the intramedullary nail probably allowed some medial translation of the shaft (left: preoperative, middle: postoperative, right: ossified).
the PFN, fixation failure (collapse and cut-out) was more common with the latter implant. The explanation for this may be in the sliding mechanism of the implant, which has shown to differ considerably between the implants used in the proximal femur.5 Sliding characteristics of the implants need further investigation and development to produce safer devices for these difficult fractures. There were no re-fractures of the femoral shaft needing revision probably because distal locking was routinely used in these very unstable fractures. During the study period, many stable pertrochanteric fractures were fixed with the SGN without distal locking and most of the peri-implant fractures occurred in those cases. When distal locking was performed the risk of re-fracture was lower. We believe this connection has not been reported before. Cephalomedullary nailing requires a meticulous planning and technique including routine use of distal locking screws. The most important finding was that cephalomedullary nailing is a very reliable fixation, when the fracture is well reduced and the implant ideally placed. In this series, there was only one failure after 47 properly performed operations. Closed reduction of the fracture, in which the proximal fragment typically is flexed, laterally and externally rotated, can be extremely difficult. Though the CMN is designed for mini-invasive operative technique, reverse obliquity intertrochanteric fractures often require a wide, open procedure. When the greater trochanter is detached and lateral fracture line runs just at the entry point of the lag screw, an additional cable around the bone may be needed to hold
the trochanter in place giving more stability to the whole osteosynthesis (Fig. 2). The length of the intramedullary nail is important. We feel that the TGN (18 cm) is too short for this particular fracture pattern. On the other hand, when using the long nails in very proximal femoral fractures, there is a risk of distal metaphyseal fracture because of mismatch of the curvature of the nail and the femur in the elderly population. In conclusion, reverse obliquity fractures of the intertrochanteric region of the femur are challenging to treat whatever implant is used. A basic demand for successful treatment is adequate fracture reduction, which often needs an open procedure. With a properly placed CMN excellent results can be expected.
References 1. Adams CI, Robinson CM, Court-Brown CM, McQueen MM. Prospective randomized controlled trial of an intramedullary versus dynamic screw and plate for intertrochanteric fractures of the femur. J Orthop Trauma 2001;15(6):394—400. 2. Babst R, Renner N, Biedermann M, Rosso R, Heberer M, Harder F, et al. Clinical results using the trochanter stabilizing plate (TSP): the modular extension of the dynamic hip screw (DHS) for internal fixation of selected unstable intertrochanteric fractures. J Orthop Trauma 1998;12(6):392—9. 3. Haidukewych GJ, Israel TA, Berry DJ. Reverse obliquity fractures of the intertrochanteric region of the femur. J Bone Join Surg (Am) 2001;83(5):643—50. 4. Henry B, Stocks G, Bini J, Heinrich M. Reverse obliquity intertrochanteric fractures: suggestions for management in the elderly. In: Proceedings of the Reading at the Annual Meeting of the Orthopaedic Trauma Association. BC, Canada: Vancouver; 8—10 October 1998.
Second-generation cephalomedullary nails
5. Loch DA, Kyle RF, Bechtold JE, Kane M, Anderson K, Sherman RE. Forces required to initiate sliding in second-generation intramedullary nails. J Bone Joint Surg (Am) 1998;80(11): 1626—31. 6. Orthopaedic Trauma Association, Committee for coding and classification: fracture and dislocation compendium. J Orthop Trauma 1996;10(1 Suppl):1—154.
183
7. Parker MJ, Handoll HH. Gamma and other cephalocondylic intramedullary nails versus extramedullary implants for extracapsular hip fractures. Cochrane Database Syst Rev 2000;2:CD000093. 8. Rokito AS, Koval KJ, Zuckerman JD. Technical pitfalls in the use of the sliding hip screw for fixation of intertrochanteric fractures. Contemp Orthop 1993;26(4):349—56.
Second-generation cephalomedullary nails in the treatment of reverse obliquity intertrochanteric fractures of the proximal femur ¨rvinen Seppo E. Honkonen*, Kimmo Vihtonen, Markku J. Ja Department of Surgery, Division of Orthopaedics and Traumatology, University Hospital of Tampere and Medical School, University of Tampere, P.O. Box 2000, FIN-33521, Tampere, Finland Accepted 17 May 2003
KEYWORDS Reverse obliquity intertrochanteric fracture; Cephalomedullary nailing
Summary Since 1996, in Tampere University Hospital, a second-generation cephalomedullary nail (CMN) has been the implant of first choice in reverse obliquity fractures of the proximal femur. Between 1996 and 1999 we treated 77 such fractures, of which 72 were fixed with the CMN. There were six re-operations (8.3%). An anatomic or nearly anatomic reduction and a properly placed implant were found in 47 cases with one failure. An unacceptable postoperative radiological result was seen in 25 cases resulting in five re-operations (P ¼ 0:029). In 12 of 14 open procedures a cable was added to stabilise the greater trochanter and none failed. Four of five fractures fixed with the sliding hip screw failed. Our results using the CMN in reverse obliquity intertrochanteric fractures compares favourably to the results in earlier reports where extramedullary implants are used. ß 2003 Elsevier Ltd. All rights reserved.
Introduction In the literature on the treatment of extracapsular fractures of the proximal femur, reverse obliquity intertrochanteric fractures (type 31.A3 according to the Orthopaedic Trauma Association classification6) are often ignored, or obviously classified into ‘‘unstable’’ intertrochanteric or subtrochanteric fractures. Biomechanically they differ from other intertrochanteric fractures, because the main fracture line runs from distal—lateral to proximal—medial (below the greater trochanter to the lesser trochanter) and almost parallel with the loading force. There is only one study that addresses the results of treatment of this particular fracture *Corresponding author. Tel.: þ358-3-2474612; fax: þ358-3-2474358. E-mail address: [email protected] (S.E. Honkonen).
pattern, suggesting that the fracture is not reliably treated by conventional extramedullary implants.3 We have routinely used second-generation cephalomedullary nails (CMN) in all types of extracapsular fractures of the proximal femur for 10 years. Increasing experience in indications and in technical performance led us to revise our treatment protocol so that since 1996 the CMN has been the first choice implant in the treatment of reverse obliquity intertrochanteric fractures. The purpose of this retrospective study is to analyse the results of the intramedullary fixation in these challenging fractures.
Patients and methods According to the computerised patient register of Tampere University Hospital, by using the codes S72.1 and S72.2 of the International Statistical
0020–1383/$ — see front matter ß 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0020-1383(03)00208-0
180
Classification of Diseases version 10 (ICD-10), 327 patients were treated for intertrochanteric or subtrochanteric fracture between January 1996 and December 1999. After approval from the Ethical Committee of Tampere University Hospital, clinical records and radiographs that had been made at the time of the injury or immediately postoperatively for these patients were reviewed, and a reverse obliquity fracture pattern (type 31.A3 according to the Orthopaedic Trauma Association6) was identified in 77 patients. According to the treatment protocol of our clinic, cephalomedullary nailing was the preferred method in this particular fracture type. The patients were operated on within three days of admission by one of several orthopaedic surgeons or residents in training. Mini-invasive reduction and nailing was always attempted, but keeping in mind the importance of good reduction, an open procedure was highly recommended. At the start of the study the Standard Gamma Nail (SGN, Stryker-Howmedica) and the Long Gamma Nail (LGN, StrykerHowmedica) were in use. Later the Trochanteric Gamma Nail (TGN, Stryker-Howmedica) and the Proximal Femoral Nail (PFN, Stratec Medical) were available as well. The surgeon performing the operation was free to choose the implant. The medullary canal of the femur was reamed 2—3 mm wider than the diameter of the nail. In open procedures, when it was evident that the implant could not stabilise the greater trochanter, a cable (Dall-Miles, Stryker-Howmedica) was mounted using a special cannulated hook to secure reduction and stability. One or two distal locking screws were used routinely. No primary bone grafting was performed. From the first postoperative day, if possible, the patients were encouraged to walk with a rollator or crutches allowing half to full weight bearing. Preand postoperative radiographs were available in all cases. The reduction was regarded as acceptable if there was no varus malalignment of the proximal fragment or if there was less than 10 mm translation between the main fragments. The acceptable position of the tip of the lag screw was in the lower part of the femoral head in the AP-view and in the central third in the lateral view and the distance from the articular surface less than 10 mm. The follow-up was arranged together with our outpatient policlinic and the health centres responsible for aftercare and rehabilitation. When implant or fracture complication occurred or was suspected, the radiographs were sent to us for analysis. Altogether 42 cases were in active follow-up on average 19 weeks (3—52 weeks). The radiographs were checked by one surgeon (SEH). All re-operations were performed in our trauma unit. The primary outcome measure was fixation failure needing re-operation.
S.E. Honkonen et al.
Cross-tabulations were analysed using Fisher’s exact test. The computation was carried out using StatXact for Windows Software (version 4).
Results Of the 77 reverse obliquity intertrochanteric fractures, 72 were fixed with the CMN. There were 48 women, with an average age of 77.6 years (range 44—96) and 24 men, with an average age of 64.0 years (range 32—92). Ninety-six percent of the fractures were caused by simple falling indicating osteoporotic bone quality of the patients. Six of the 72 cephalomedullary nailings (8.3%) failed and resulted in major revision. Three of 44 simple fracture patterns and 3 of 28 multifragmentary fractures were revised (P ¼ 0:677). A minimally invasive procedure was performed in 58 fractures, of which, in a retrospective evaluation, 21 were poorly reduced and/or fixed with a non-ideally placed implant. Four resulted in re-operation, while of the remaining 37 fractures with anatomical reduction and with an ideally placed implant there was only one re-operation (P ¼ 0:076). An open procedure was performed in 14 cases leading to one failure, in which the fracture reduction had remained poor. In 12 of the open procedures a cable was added to stabilise the greater trochanter and none of these failed. Altogether, an acceptable radiological postoperative result was found in 47 cases leading to one re-operation. An unacceptable radiological result was seen in 25 cases leading to five re-operations (P ¼ 0:029). The eventual outcome of each intramedullary implant is seen in Table 1. The failure mode was collapse of the fracture and cut-out of the lag screw in five cases and non-union in one case. Minor procedures included one dynamisation of the SGN because of delayed union, and three removals of the antirotation screw using the PFN. In the study group, there was no peri-implant fractures needing revision. Only one split of the distal femoral metaphysis occurred using the LGN. We checked all the patients with extracapsular fractures of the proximal femur (327 patients) and found four shaft fractures in 123 standard gamma nailings (3.3%). Eighty of them were distally locked leading to one re-fracture, while there were three re-fractures in the remaining 43 cases without distal locking (P ¼ 0:122). Respectively, all 71 PFNs were used with distal locking leading to one re-fracture. Thirteen patients died within 3 months of the accident. None of them were known to have complications related to the implant. There were no deep infections in the series.
Second-generation cephalomedullary nails
Table 1
181
The eventual outcome of each implant
Standard gamma nail Trochanteric gamma nail Long gamma nail Proximal femoral nail All
Number
Good reduction and properly placed implant
Re-operation
28 4 4 36 72
20 (71.4%) 3 1 24 (66.7%) 48 (66.7%)
0 1 0 5 6 (8.3%)
In the remaining five reverse obliquity fractures, against our treatment protocol, a sliding hip screw (SHS) was used and four of them failed because of collapse of the fracture and/or cut-out of the lag screw.
Discussion Reverse obliquity fractures of the intertrochanteric region of the femur account for 5% of all inter- and subtrochanteric fractures.3 Our high percentage (23%) is explained by the fact that we have centralised the most difficult fractures of the proximal femur in one trauma unit. A hallmark of this very unstable fracture type is a horizontal or reversed fracture line starting laterally below the greater trochanter. The biomechanics of the SHS leads the fracture fragments to separate rather than compress resulting in an unacceptably high rate of failures. Rokito et al. concluded that the SHS might not be the implant of choice for reverse obliquity fractures of the intertrochanteric region.8 In our series, four of five cases fixed with the SHS had to be
revised. In two other reports the failure rate has been 24 and 56%.3,4 Babst et al. reported that addition of a trochanteric blocking plate to the SHS could effectively support the unstable greater trochanter and prevent rotation and impaction of the head—neck fragment.2 The lowest failure rate (20%) has been reported using the blade-plate or the dynamic condylar screw.3 Second-generation cephalomedullary nails have been in use more than 10 years, but clear indications for their use still are unknown. In pertrochanteric fractures, where the main fracture line is perpendicular to the loading forces, clinical results of the SHS still seem to be better.1,7 In the reverse obliquity intertrochanteric fracture the CMN theoretically provides better stability, because the leverarm is relatively short and the upper part of the intramedullary nail leans against the proximal fragment preventing medial sliding of the distal fragment (Fig. 1). In our patients, the overall failure rate of 8.3% compares favourably to the failure rate found in extramedullary fixations. Though the rate in achieving anatomic reduction and ideal placement of the implant did not differ using either the SGN or
Figure 1 No varus malalignment of the proximal fragment, well reduced medial cortices and ideally placed implant effectively prevent the medial translation of the shaft (left: preoperative, middle: postoperative, right: ossified).
182
S.E. Honkonen et al.
Figure 2 Reduction needed open procedure and a cable was added to improve fixation, but too lateral entry point of the intramedullary nail probably allowed some medial translation of the shaft (left: preoperative, middle: postoperative, right: ossified).
the PFN, fixation failure (collapse and cut-out) was more common with the latter implant. The explanation for this may be in the sliding mechanism of the implant, which has shown to differ considerably between the implants used in the proximal femur.5 Sliding characteristics of the implants need further investigation and development to produce safer devices for these difficult fractures. There were no re-fractures of the femoral shaft needing revision probably because distal locking was routinely used in these very unstable fractures. During the study period, many stable pertrochanteric fractures were fixed with the SGN without distal locking and most of the peri-implant fractures occurred in those cases. When distal locking was performed the risk of re-fracture was lower. We believe this connection has not been reported before. Cephalomedullary nailing requires a meticulous planning and technique including routine use of distal locking screws. The most important finding was that cephalomedullary nailing is a very reliable fixation, when the fracture is well reduced and the implant ideally placed. In this series, there was only one failure after 47 properly performed operations. Closed reduction of the fracture, in which the proximal fragment typically is flexed, laterally and externally rotated, can be extremely difficult. Though the CMN is designed for mini-invasive operative technique, reverse obliquity intertrochanteric fractures often require a wide, open procedure. When the greater trochanter is detached and lateral fracture line runs just at the entry point of the lag screw, an additional cable around the bone may be needed to hold
the trochanter in place giving more stability to the whole osteosynthesis (Fig. 2). The length of the intramedullary nail is important. We feel that the TGN (18 cm) is too short for this particular fracture pattern. On the other hand, when using the long nails in very proximal femoral fractures, there is a risk of distal metaphyseal fracture because of mismatch of the curvature of the nail and the femur in the elderly population. In conclusion, reverse obliquity fractures of the intertrochanteric region of the femur are challenging to treat whatever implant is used. A basic demand for successful treatment is adequate fracture reduction, which often needs an open procedure. With a properly placed CMN excellent results can be expected.
References 1. Adams CI, Robinson CM, Court-Brown CM, McQueen MM. Prospective randomized controlled trial of an intramedullary versus dynamic screw and plate for intertrochanteric fractures of the femur. J Orthop Trauma 2001;15(6):394—400. 2. Babst R, Renner N, Biedermann M, Rosso R, Heberer M, Harder F, et al. Clinical results using the trochanter stabilizing plate (TSP): the modular extension of the dynamic hip screw (DHS) for internal fixation of selected unstable intertrochanteric fractures. J Orthop Trauma 1998;12(6):392—9. 3. Haidukewych GJ, Israel TA, Berry DJ. Reverse obliquity fractures of the intertrochanteric region of the femur. J Bone Join Surg (Am) 2001;83(5):643—50. 4. Henry B, Stocks G, Bini J, Heinrich M. Reverse obliquity intertrochanteric fractures: suggestions for management in the elderly. In: Proceedings of the Reading at the Annual Meeting of the Orthopaedic Trauma Association. BC, Canada: Vancouver; 8—10 October 1998.
Second-generation cephalomedullary nails
5. Loch DA, Kyle RF, Bechtold JE, Kane M, Anderson K, Sherman RE. Forces required to initiate sliding in second-generation intramedullary nails. J Bone Joint Surg (Am) 1998;80(11): 1626—31. 6. Orthopaedic Trauma Association, Committee for coding and classification: fracture and dislocation compendium. J Orthop Trauma 1996;10(1 Suppl):1—154.
183
7. Parker MJ, Handoll HH. Gamma and other cephalocondylic intramedullary nails versus extramedullary implants for extracapsular hip fractures. Cochrane Database Syst Rev 2000;2:CD000093. 8. Rokito AS, Koval KJ, Zuckerman JD. Technical pitfalls in the use of the sliding hip screw for fixation of intertrochanteric fractures. Contemp Orthop 1993;26(4):349—56.