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(iii) The difficult extracapsular hip fracture (including subtrochanteric)
Current Orthopaedics (2000) 14, 93–101 © 2000 Harcourt Publishers Ltd doi:10.1054/cuor.2000.0094, available online at http://www.idealibrary.com on
Mini-symposium: The difficult neck of femur fracture
(iii) The difficult extracapsular hip fracture (including subtrochanteric)
L. Ceder
three or more major fragments has the potential of being classified as a difficult hip fracture. The subtrochanteric fracture is more difficult than the trochanteric one because of the larger biomechanical forces acting around the subtrochanteric region which is the most highly stressed part of the skeleton.3 This makes both reduction and fixation difficult. The medial and postero-medial cortices are the sites of very high compressive forces, while the lateral cortex experiences high tensile forces. Restoration of the medial cortex is important in treating these fractures. Trochanteric fractures occur in cancellous bone with an abundant blood supply. Subtrochanteric fractures occur mainly in cortical bone with less vascularity and this is why the potential for healing is diminished as compared with intertrochanteric fractures.
INTRODUCTION An extracapsular hip fracture can be defined as a fracture which occurs in the region between the attachment of the hip joint capsule on the femur and a line 5 cm distal to the lesser trochanter (Fig. 1).1 What is a difficult extracapsular hip fracture? What are the methods for treating it? Which method is the best choice? In this review article, I shall try to discuss these questions by referring to the general consensus found in some excellent handbooks,1,2 review papers3,4 and recent publications on hip fractures but I have also added some personal aspects based on my own experience.
WHAT IS A DIFFICULT HIP FRACTURE? There is general agreement that where appropriate surgical facilities and expertise exist, almost all extracapsular hip fractures should be treated surgically.1–4 The outcome of different operations has taught us which fracture types have a high risk of complications. The difficult extracapsular hip fracture can, therefore, be defined as the fracture with an increased or high risk of fixation failure. The evolution of fixation implants has also taught us to choose the correct implant for a specific fracture type and we are still learning. As a general rule, two-part undisplaced or displaced fractures are stable after reduction.1–4 Almost any fixation implant will suffice. Every fracture with
ANALYSIS OF CLASSIFICATION SYSTEMS FOR EXTRACAPSULAR HIP FRACTURES The simplest subdivision of extracapsular hip fractures is into trochanteric and subtrochanteric fractures. However, even this classification is vague, when the fracture line often crosses these anatomic regions. Also the border between the subtrochanteric and the diaphyseal regions is variable. Most classifications state that the diaphysis commences a distance of 5 cm from the distal part of the lesser trochanter.1,2 The transtrochanteric zone2 (Fig. 1) belongs to the trochanteric region, in which intertrochanteric fractures often are synonymous with pertrochanteric. Many different classification systems have been proposed through the years, from simple to complex systems. Each of these classifications has different degrees of inter-observer variation. For this review, I have chosen two of the most commonly used,1,2 i.e.
L. Ceder MD, PhD, Associate Professor, Lund University and Consultant Orthopaedic Surgeon, Department of Orthopaedics, Helsingborg Hospital, SE-251 87 Helsingborg, Sweden. Tel: +46 42 102410. Fax: +46 42 102450.
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Fig. 3 Seinsheimer classification of subtrochanteric fractures. (Reproduced with kind permission from Parker MJ, Pryor GA. Hip fracture management. Oxford: Blackwell Scientific Publications, 1993.) Fig. 1 Primary classification of proximal femoral fractures. (Adapted from Parker MJ, Pryor GA, Thorngren K-G. Handbook of hip fracture surgery. Oxford: Butterworth Heinemann, 1997. Reprinted with kind permission from Butterworth Heinemann Publishers, a division of Reed Educational & Professional Publishing Ltd.)
Fig. 2 Jensen and Michaelsen classification of trochanteric fractures. (Reproduced with kind permission from Parker MJ, Pryor GA. Hip fracture management. Oxford: Blackwell Scientific Publications, 1993.)
the Jensen and Michaelsen (Fig. 2), a modification of the Evans classification, for the trochanteric, and the Seinsheimer for the subtrochanteric fracture (Fig. 3). Both classifications are mainly based on the number of major bone fragments and the location and shape of the fracture lines. Most classifications divide the fractures into stable and unstable fracture configurations or patterns. The following factors cause instability and with that an increase in the rate of fixation failure:
1. According to many classifications, the main key to fracture stability is determined by the presence of postero-medial bony contact, which acts as a support against varus collapse in trochanteric fractures but principally also in subtrochanteric fractures.1–4 2. Another important key to fracture stability is the main direction of the fracture line, especially with a subtrochanteric component. Usually, the fracture extends obliquely from the lesser to the greater trochanter. In reverse obliquity the fracture extends from the lateral cortex, medially and proximally to the lesser trochanter. This fracture type is inherently unstable despite an adequate reduction due to pull of the abductors on the proximal fragment and pull of the abductors on the distal fragment. A transverse fracture in the trans-trochanteric zone has a similar inherent instability. 3. The degree of comminution and the gross displacement of bony fragments are important for stability. The more of these components in the fracture the more will the fracture collapse. 4. The fracture configuration of the lateral cortex of the greater trochanter has been given less importance for fracture stability in the different fracture classifications. A fracture without a lateral cortical spike from the femoral shaft or a fracture with a comminuted area around the entry site of the lag screw gives no lateral support and has an increased risk of medialization5,6 of the femoral shaft due to the pull of the adductors. In summary, the trans-trochanteric zone is the danger area: • An unstable lateral cortex – medialization • An unstable medial cortex – varisation • An oblique reversity – medialization.
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TREATMENT OPTIONS The aim of the surgical treatment is to stabilize the fracture in order to allow early weight-bearing. The stability of the fracture fixation depends on several factors: bone quality, fracture configuration, mode of fracture reduction, implant design and placement of the implant. The surgeon has to consider all these factors but can only control the quality of reduction, implant choice and placement of the implant to give the patient the best conditions for satisfactory healing of the fracture.
SURVEY OF IMPLANT DESIGNS In the 1930s, the first implants to be used for extramedullary fixation of extracapsular hip fractures were the static, rigid or fixed nail plates.1,3 The outcome of the fixation in the stable fracture was often satisfactory. However, in the unstable fracture these implants did not allow impaction of the fracture fragments to occur. As a result, there was an increased stress on the implant. Therefore, it became a race between bony union and failure of the fixation, either by the implant penetrating and cutting out of the femoral head or ultimately undergoing fatigue failure and breaking. The shortcomings of the static implants led to development of new techniques to recreate medial stability. Various types of osteotomies in combination with a static implant were tried with some success. The introduction of sliding implants that allowed impaction of the fracture fragments to occur in the unstable fracture drastically reduced the rate of fixation failure in unstable fractures. These extramedullary dynamic implants have become the gold standard in the fixation of extracapsular hip fractures.1–4 The sliding element is a nail or usually a lag screw, which gives dynamization in the direction of the femoral neck. This dynamization principle is currently used in many implants with synonymous terms such as dynamic hip screw, compression hip screw or sliding hip screw (Fig. 4). Even the dynamic extramedullary implants become static as the fracture line extends more distally into the subtrochanteric region.1,2 Instead of being a loadsharing implant, it turns into a load-bearing one with increased stress on the implant. In an unstable fracture, the risk of fixation failure will increase. In some fracture patterns, e.g. reverse obliquity, the dynamization may lead to an excessive medialization of the femoral shaft with increased stress on the implant resulting in hardware failure (Fig. 5).5,6 Intramedullary (IM) nails1–4 have the advantage of preventing the medialization and of providing better resistance to the strong bending forces in the subtrochanteric region. The IM nails can be divided into cephalo-medullary, with or without interlocking, and
Fig. 4
The sliding hip screw (SHS).
condylo-cephalic types. The most well-known implants in the latter category are the Ender pins, which are inserted in the knee region. Unfortunately, malrotation with distal and proximal migration or penetration of the pins with shortening of the leg often occurred in the unstable fracture requiring reoperations; thus the use of this implant is no longer appropriate. The Zickel nail was one of the first cephalo-medullary nails without interlocking. It has been reported to achieve high union rates but has no rotational stability. The so-called second generation of cephalo-medullary nails has the possibility of distal interlocking, which means control of rotation and of leg length. These include the Gamma nail, the intramedullary hip screw, the Russel-Taylor reconstruction nail and the proximal femoral nail.
THE SLIDING HIP SCREW AND ITS RECENT CHALLENGERS In 1952, von Pohl invented the sliding hip screw (SHS) but it took more than 20 years for this implant to be generally accepted in the orthopaedic community. The SHS is still the most commonly used implant in the treatment of extracapsular hip fractures and every new fixation method has to be compared with this device.1,2 Recently, various modifications and adaptations to this implant, the rigid nail plate and the IM nail, including modifications in reduction techniques, have been introduced with the aim of reducing the risk of fixation failure. However, the role of some of these newer implants is unproven and further research is needed to establish their use. Such devices include the dynamic Martin screw (a dynamic angle-adapted link plate), the percutaneous compression plate, the
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Trochanteric Stabilizing Plate (TSP), the Medoff Sliding Plate (MSP), the Rigidity Augmentation Baixauli (RAB) plate and the interlocking cephalomedullary implants such as the Gamma nail. The last four implants are further discussed.
intensifier.1–4 The lag screw should be placed within 10 mm of the hip joint to obtain a good purchase in the subchondral bone. With the use of a side plate, at least four screws or eight cortices should be fixed distal to the fracture.
The sliding hip screw
Fixation failures
The technique of fracture reduction is similar for most implants but the placement of the implants can differ. For this, I have to refer to operative manuals.1,2
Usually, the SHS, after correct reduction and placement, is adequate in most cases. However, in prospective studies of unstable intertrochanteric fractures, the SHS has a 5–20% rate of fixation failure.7–9 The most common failure is a cut-out of the lag screw from the femoral head, which is often associated with poor reduction or placement of the device.1–4 The main reason is varus collapse of the fracture often due to postero-medial instability and/or excessive femoral medialisation with loss of lag screw slide and poor bone-to-bone contact. If there is a large postero-medial fragment, an attempt should be made to internally fix the fragment in a near anatomic position with a lag screw and/or cerclage wire, which should not interfere with the sliding mechanisms of the implant. Even a non-anatomic reduction is of value as it fills up the postero-medial defect to provide a buttress against varus displacement. However, fixation of the posteromedial fragment may be difficult, particularly if comminution is present. Therefore, in the elderly osteoporotic patient the dissection may do more harm than good by devascularizing the fragments without increasing the stability.1,2 Bone grafting may be used to replace a large bone defect. Augmentation with cement has been advocated as increased resistance to cut-out has been shown biomechanically. However, the distribution of the cement is difficult to control and the cement may interfere with the sliding mechanism of the implant and increase the risk of non-union. Therefore cement augmentation is only indicated in a metastatic fracture.1,2 The deposition of an osteoconductive apatite (Norian SRS) has been tested biomechanically for augmented fracture fixation but its clinical role remains at present uncertain.10 All the above supplementary surgical procedures prolong the operation time and may influence the outcome especially in the elderly patient, as extensive dissection is required, injuring surrounding structures with increased risk of bleeding and infection. Other associated fixation failures are lag screw penetration into the joint, dissociation of the plate from the shaft (by screws breaking or pulling out), implant breakage or bending. The rate of non-union is approximately 2% in intertrochanteric fractures and higher in subtrochanteric fractures.1
Reduction of the fracture A fracture table, which allows biplanar visualization of the entire proximal femur of the supine patient, is needed for both closed and open manoeuvres, which should aim at an anatomical reduction of the fracture. Reduction with varus angulation or posterior sag will result in an incorrect position of the lag screw. Correction of varus angulation will occur with additional traction on the leg, and the use of a periosteal elevator or crutch will correct posterior sag during surgery. Overdistraction of the fracture must be avoided during the operation. If a sliding implant is fixed to the femur with a fracture gap, the dynamic capacity is reduced with an increased risk of converting the implant into a rigid system, because excessive postoperative collapse may exceed the sliding capacity of the implant. This can be avoided by releasing the traction prior to the fixation of the plate to the shaft and manually impacting the distal fragment into the proximal fragment, taking care to maintain the reduction.4 However, a small opening of the fracture medially in a valgus reduction is of value, as subsequent impaction of the fracture will improve the mechanical stability.1,2 Fixation of an extracapsular fracture on the fracture table with the patella pointing to the ceiling avoids any permanent rotational deformity. Controlled medialization of the femoral shaft has been done as a medial displacement osteotomy to increase the stability of the fracture and thus decrease the risk of implant cut-out of the femoral head. However, more recent biomechanical and clinical studies1–4 have shown that this surgical procedure is not appropriate for a SHS and will increase the risk of fixation failure. Anatomic reduction allows greater load-sharing by the bone than medial displacement osteotomy, and with the SHS, stability is not improved by ostetomy. Placement of the implant Correct reduction of the fracture is the prerequisite for accurate positioning of the lag screw. Most surgeons agree that the direction should be at 135º alignment with the femur, and that the lag screw should be placed centrally or slightly inferior on the AP view and centrally on the lateral view using the image
The Trochanteric Stabilizing Plate The medialization of the femoral shaft can become disadvantageous, when it is excessive. It can consume
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all sliding capacity of the lag screw and turn it into a rigid fixation system similar to the rigid nail plate. The stress on the plate will then increase and, if the fracture does not heal in time, the plate will break or dissociate from the shaft, or cut-out may occur (Fig. 5). The reason is a lack of lateral support for the proximal fragment in the trans-trochanteric zone as described earlier. The TSP has been developed for use with the SHS to decrease this medialization. In a comparative study of unstable trochanteric and subtrochanteric fractures, fixation with the dynamic hip screw and the TSP showed a significant decreased sliding of the lag screw but no difference in failure rate compared with the Gamma nail and the compression hip screw.9 This decrease in slide from the TSP is controversial as it can turn the implant rigid, resulting in fixation failure.6 The Medoff Sliding Plate The most dynamic implant of all is the MSP (Fig. 6). It is similar to the SHS but a coupled pair of sliding elements has replaced the side-plate. As an ‘add-on’ plate, it can be combined with any lag screw and its dynamic capacity along both the shaft and the neck of femur gives biaxial dynamisation.7 By using a locking set screw, the sliding along the neck of femur can be stopped and only sliding along the femoral shaft occurs (uniaxial dynamization). The prerequisite for this is the yoking procedure as described below. This allows the barrel-plate to slide inside the side-plate. The idea of an additional dynamization along the femoral shaft with the side-plate of a sliding hip screw came in the 1950s. However, distal enlargement or slotting of the entry hole of the barrel (the yoking procedure) was a prerequisite to allow axial impaction at the fracture site of an intertrochanteric fracture.11 Otherwise, the plate-barrel would impinge on the lateral cortex of the femur, which then obstructs axial compression. A sliding implant with a screw- plate angle closest to the hip joint reaction force, which is 159º to the vertical plane, allows optimum sliding and impaction.3 The dual sliding of the MSP has a barrelplate slide of 180º to the side-plate and a lag screw slide of 135º to the barrel-plate. Theoretically, the advantage of load-sharing is that it gives impaction of the fracture with increased bone-to-bone contact, which improves fracture stability. This should enhance fracture healing and decrease the stress on the implant, thus reducing the risk of fixation failure. As much as 75% of the load applied to a stabilized hip fracture may be absorbed by the bone itself. The greater load sharing capacity of the MSP compared to the SHS has been shown in biomechanical tests; in subtrochantric fractures, 3–4 times higher plate strain was recorded for the SHS compared to the MSP, and in unstable intertrochanteric fractures, the MSP demonstrated more effective stress transfer to the fracture surface of the proximal medial cortex than
Fig. 5 Excessive femoral medialization resulting in non-union, cut-out of lag screw, plate dissociation with breakage of cortical bone screws.
the SHS.6 The reason is probably that the MSP restores medial continuity by decreasing the medial fracture gap by vertical impaction. The indications for the MSP are the unstable intertrochanteric, the combined inter/subtrochanteric fracture and the high subtrochanteric fracture. If the proximal fracture fragment is long and is fixed to the side-plate by the proximal cortical plate screw, no sliding occurs. The MSP gives the surgeon the option of three different dynamization modes to individualize the treatment of extracapsular hip fractures: 1. Uniaxial dynamization is useful in the treatment of pure subtrochanteric fractures, in fractures with a transverse or oblique reversity or without a lateral support in the trans-trochanteric zone. 2. Staged biaxial dynamization, i.e. initial plate sliding followed by later lag screw unlocking, can reduce the degree of femoral medialization and prevent or stop lag screw migration in the head of femur. This mode of dynamization can be of value in fractures with a complete plate slide and risk of lag screw migration, which is most frequent in the combined inter/subtrochanteric fracture (Fig. 6).
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A
B
3. Biaxial dynamization is indicated in the treatment of most unstable intertrochanteric fractures but may also be used in subtrochanteric fractures with lateral support in the trans-trochanteric zone. By using the right dynamization mode of the MSP, it has been possible to reduce the rate of fixation failure to 3% or less in the unstable intertrochanteric fracture (biaxial dynamization), in the high subtrochanteric fracture (uniaxial dynamization) or in the combined inter/subtrochanteric fracture (staged biaxial dynamization).6,7 The Rigidity Augmentation Baixauli plate and indirect reduction technique The RAB plate is similar to the rigid nail plate but is reinforced with a medial strut, which acts as a buttress
C
Fig. 6 The simplified 6-hole Medoff sliding plate (MSP), showing uniaxial dynamization with the (A) maximal amount of plate sliding available; (B) complete uniaxial plate slide; and (C) removal of locking set screw which allows screw in barrel sliding (staged biaxial dynamization).
rod to resist varus collapse (Fig. 7). Mechanical tests with loading to failure showed that the RAB plate was two and three times stronger than that of the Gamma nail and the SHS, respectively.12 The strength of the RAB plate is five times greater with the strut than without it. The indications for the RAB plate are the unstable intertrochanteric and high subtrochanteric fracture but it should not be used if the fracture line goes distal to the lateral end of the strut. The inventor12 states that an anatomical reduction of the fracture, although advisable, is not necessary for its implantation. Neither are complementary techniques necessary, such as reduction and screw fixation of an intermediate fragment or grafting to fill a bone gap. In his retrospective series of 358 patients, 44% had stable fractures, 5% fixation failure and 1% non-union. There was almost no radiologic settling of the fractures in the uncomplicated cases. In a randomized study8 of the RAB plate versus the SHS in 233 patients with unstable trochanteric including high subtrochanteric fractures, 8% fixation failures including non-union were reported. The use of the RAB plate is still experimental and should not be used outside research settings. Indirect reduction and fixation The technique of indirect reduction of fracture fragments with a femoral distractor and the use of a tensioning device to trap and lock the fragments medially has been used in combination with the 95º condylar blade plate for fixation in comminuted
The difficult extracapsular hip fracture
Fig. 7 The rigidity augmentation Baixauli (RAB) plate. (Adapted with kind permission from Baixauli F, Vicent V, Baixauli E et al. A reinforced fixation device for unstable intertrochanteric fractures. Clin Orthop 1999; 361: 205–215.)
Fig. 8 The Gamma nail.
subtrochanteric fractures.13 The blade plate functions as a lateral tension band, when the postero-medial cortex is restored. The vascularity of the fracture fragments is preserved and no bone graft is used. The prerequisite for this technique to work is that bony contact must have been achieved under compression to allow the bone to share the load with the blade plate. Otherwise, the failure rate is high. The Intramedullary Nail Küntscher, in 1939, was probably the first to report on the concept of intramedullay fixation of subtro-
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Fig. 9 Classification of subtrochanteric fractures, used at the Hennepin County Medical Center, showing various methods of treatment. A type-I simple, high fracture involves the lesser trochanter and is treated with a SHS or a second- generation locking nail. In a type-I comminuted fracture that involves the piriform fossa, the SHS is preferred because of the difficulty encountered with insertion of an intramedullary nail. In a type-II simple or comminuted low fracture, a first generation locking nail (with a single locking screw) is used. (Adapted with kind permission from Kyle RF with contributors. Fractures of the proximal part of the femur. J Bone Joint Surg 1994; 76: 924–950.)
chanteric fractures with a ‘Y nail’.3 Since then several types of intramedullary devices have been developed as described above. The latest development in IM nails and challenger to the SHS are the cephalomedullary implants with distal interlocking (Fig. 8). They are also used in intertrochanteric fractures, especially when unstable. These newer implants combine the features of a SHS and an IM nail. Theoretically, they can be inserted in a closed manner with limited fracture exposure, which should result in less blood loss and less tissue damage than occur with the SHS. They are considered more technically demanding to use and have the additional procedure of distal interlocking. In spite of the lack of dynamization along the femoral shaft, there is a high union rate. A biomechanical evaluation of the short Gamma nail in an experimental model of stable and unstable intertrochanteric fractures reported that the Gamma nail transmitted decreasing load to the calcar with decreasing fracture stability.4 Virtually no strain on the bone was seen in four-part fractures with the posteromedial fragment removed. Insertion of the distal locking screws did not change the pattern of proximal femoral strain. Due to the low compressive load on the calcar, an increased load occurs at the tip of the nail. This increases the stress on the bone around the distal tip of the implant. However, with a long stem this load is redistributed throughout the distal femur without significant increase of the distal femoral stress. There are specific problems with the IM nails during surgery and later.1,2 Intraoperative fracture of the femur
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Table 1 Survey of design and function (*) of the SHS and some challengers, including fixation failure
SHS (•) w. TSP (•) MSP – Biaxial – Unaxial – Staged RAB Gamma nail (•)
Special feature
Prevents medialization
Dynamic capacity
Load sharing
Fixation** failure (%)
Randomized trials
None Lateral buttress
No ++
++ +
++ +
0–20 6
Many None
Unlocked Locked Secondary unlocking Medial buttress Distal interlocking
+ +++ ++
+++ ++ ++(+)
+++ ++ ++(+)
0–3 0–7 –
Few Few None
+++
No
No
6–8
Few
++(+)
+
+
2–12 (³)
Several
* The graduated system is based on theory and the differences in grading may not correlate to quantity or quality but is an attempt to separate the design and function between the different implants ** May include stable fractures (•) No dynamic capacity or load sharing in the subtrochanteric region (³)Includes later fracture of femur
have been reported in approximately 3% during the insertion of the nail. Often inadequate reaming of the femur is the cause. Late femoral shaft fractures at the distal tip of the nail have been reported to occur in about 5% with the short Gamma nail. The stress riser effect of inadequate drilling of the screw holes may increase this risk. In a meta-analysis of the Gamma nail versus the dynamic hip screw for extracapsular hip fractures, the Gamma nail had a significantly increased risk of femoral shaft fractures but there was no difference in the lag screw cut-out.14 Improvements in the construction of the implant, the operative technique and development of a long stem have attempted to decrease this risk. A classification system and algorithm for the treatment of subtrochanteric hip fractures including concurrent ipsilateral femoral shaft fractures3 has been developed at the Hennepin County Medical Center (Fig. 9). At the Centre for Traumatology and Orthopaedics in Strasbourg, the short and the long Gamma nail are used to treat all trochanteric and trochantericdiaphyseal fractures independent of the complexity of the fracture and without any complementary fixations like banding, screwing, bone grafting or cement.
and of the design of different implants. After mastering the surgical technique, the thoughtful orthopaedic surgeon can choose an adequate fixation method for the specific fracture type to achieve the best result possible (Table 1). Randomized studies, comparing the SHS as the reference standard with new implants, are of utmost importance. However, it may be difficult to give such a valid statement unless larger number of patients are studied. The goal of treatment is to be able to mobilize the patient fully weight-bearing immediately after surgery. It should be possible with current surgical techniques and implants, even in the most difficult extracapsular hip fracture. Failure to achieve this should be termed a failure of treatment, and is not acceptable in elderly patients, who do not tolerate bed rest, restricted weight bearing, prolonged surgery or complications of surgical treatment. Acknowledgements The author is grateful for constructive criticism from Martyn J. Parker, MD, FRCS (Edin), Orthopaedic Research Fellow, Peterborough District Hospital, Peterborough, UK.
Endoprosthetic replacement Arthroplasty is generally not indicated and its role remains unproven. However, in the very comminuted intertrochanteric fracture a primary endoprosthetic replacement has been advocated.15 The indication for a primary arthroplasty is stronger in the combined intra/extracapsular hip fracture, where the risk of non-union and femoral head collapse is high.
HIP FRACTURE PHILOSOPHY I think it is very important to have a basic understanding of fracture configurations, of biomechanics
REFERENCES 1. Parker MJ, Pryor GA. Hip fracture management. Oxford: Blackwell Scientific Publications 1993. 2. Parker MJ, Pryor GA, Thorngren K-G. Handbook of hip fracture surgery. Oxford: Butterworth-Heinemann, 1997. 3. Kyle RF with contributors. Fractures of the proximal part of the femur. J Bone Joint Surg 1994; 76: 924–950. 4. Koval KJ, Zuckerman JD. Hip Fractures: II. Evaluation and treatment of intertrochanteric fractures. J AAOS 1994; 2: 150–156. 5. Parker MJ. Trochanteric fractures. Fixation failure commoner with femoral medialisation, a comparison of 101 cases. Acta Orthop Scand 1996; 67: 329–332. 6. Lunsjö K, Ceder L, Tidermark J et al. Extramedullary fixation of 107 subtrochanteric fractures. A randomized multicenter trial of the Medoff sliding plate versus 3 other screw-plate systems. Acta Orthop Scand 1999; 70(5): 459–466.
The difficult extracapsular hip fracture 7. Watson JT, Moed BR, Cramer KE, Kargas DE. Comparison of the compressive hip screw and the Medoff sliding plate for intertrochanteric fractures. Clin Orthop 1998: 348: 79–86. 8. Buciuto R, Uhlin B, Hammerby S, Hammer R. RAB- plate vs Richards CHS plate for unstable trochanteric hip fractures. A randomized study of 233 patients with 1-year follow-up. Acta Orthop Scand 1998; 69: 25–8. 9. Madsen JE, Naess L, Aune AK, Alho A, Ekeland A, Stromsoe K. Dynamic hip screw with trochanteric stabilizing plate in the treatment of unstable proximal fractures: a comparative study with the Gamma nail and compression hip screw. J Orthop Trauma 1998; 12: 241–248. 10. Goodman SB, Bauer TW, Carter D et al. Norian SRS cement augmentation in hip fracture treatment: laboratory and initial clinical results. Clin Orthop 1998; 348: 42–50. 11. Jarrett PJ, Fleming LL, Whitesides Jr, TE. The stable internal fixation of peritrochanteric hip fractures. In:
12. 13. 14. 15.
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Fractures of the hip. AAOS Instructional Course Lectures 1984; 33: 203–218. Baixauli F, Vicent V, Baixauli E et al. A reinforced fixation device for unstable intertrochanteric fractures. Clin Orthop 1999; 361: 205–215. Kinast C, Bolhofner BR, Mast JW, Ganz R. Subtrochanteric fractures of the femur: results of treatment with the 95 degrees condylar blade-plate. Clin Orthop 1989; 238: 122–30. Parker MJ, Pryor GA. Gamma versus DHS nailing for extracapsular femoral fractures. Meta-analysis of ten randomised trials. Int Orthop 1996; 20: 163–68. Staepperts KH, Deldycke J, Broos PLO, States FFGM, Rommens PM, Claes P. Treatment of unstable peritrochanteric fractures in elderly patients with a compression hip screw or with the the Vandeputte (VDP) endoprothesis: a prospective randomised study. J Orthop Trauma 1995; 9: 292–7.
Mini-symposium: The difficult neck of femur fracture
(iii) The difficult extracapsular hip fracture (including subtrochanteric)
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three or more major fragments has the potential of being classified as a difficult hip fracture. The subtrochanteric fracture is more difficult than the trochanteric one because of the larger biomechanical forces acting around the subtrochanteric region which is the most highly stressed part of the skeleton.3 This makes both reduction and fixation difficult. The medial and postero-medial cortices are the sites of very high compressive forces, while the lateral cortex experiences high tensile forces. Restoration of the medial cortex is important in treating these fractures. Trochanteric fractures occur in cancellous bone with an abundant blood supply. Subtrochanteric fractures occur mainly in cortical bone with less vascularity and this is why the potential for healing is diminished as compared with intertrochanteric fractures.
INTRODUCTION An extracapsular hip fracture can be defined as a fracture which occurs in the region between the attachment of the hip joint capsule on the femur and a line 5 cm distal to the lesser trochanter (Fig. 1).1 What is a difficult extracapsular hip fracture? What are the methods for treating it? Which method is the best choice? In this review article, I shall try to discuss these questions by referring to the general consensus found in some excellent handbooks,1,2 review papers3,4 and recent publications on hip fractures but I have also added some personal aspects based on my own experience.
WHAT IS A DIFFICULT HIP FRACTURE? There is general agreement that where appropriate surgical facilities and expertise exist, almost all extracapsular hip fractures should be treated surgically.1–4 The outcome of different operations has taught us which fracture types have a high risk of complications. The difficult extracapsular hip fracture can, therefore, be defined as the fracture with an increased or high risk of fixation failure. The evolution of fixation implants has also taught us to choose the correct implant for a specific fracture type and we are still learning. As a general rule, two-part undisplaced or displaced fractures are stable after reduction.1–4 Almost any fixation implant will suffice. Every fracture with
ANALYSIS OF CLASSIFICATION SYSTEMS FOR EXTRACAPSULAR HIP FRACTURES The simplest subdivision of extracapsular hip fractures is into trochanteric and subtrochanteric fractures. However, even this classification is vague, when the fracture line often crosses these anatomic regions. Also the border between the subtrochanteric and the diaphyseal regions is variable. Most classifications state that the diaphysis commences a distance of 5 cm from the distal part of the lesser trochanter.1,2 The transtrochanteric zone2 (Fig. 1) belongs to the trochanteric region, in which intertrochanteric fractures often are synonymous with pertrochanteric. Many different classification systems have been proposed through the years, from simple to complex systems. Each of these classifications has different degrees of inter-observer variation. For this review, I have chosen two of the most commonly used,1,2 i.e.
L. Ceder MD, PhD, Associate Professor, Lund University and Consultant Orthopaedic Surgeon, Department of Orthopaedics, Helsingborg Hospital, SE-251 87 Helsingborg, Sweden. Tel: +46 42 102410. Fax: +46 42 102450.
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Fig. 3 Seinsheimer classification of subtrochanteric fractures. (Reproduced with kind permission from Parker MJ, Pryor GA. Hip fracture management. Oxford: Blackwell Scientific Publications, 1993.) Fig. 1 Primary classification of proximal femoral fractures. (Adapted from Parker MJ, Pryor GA, Thorngren K-G. Handbook of hip fracture surgery. Oxford: Butterworth Heinemann, 1997. Reprinted with kind permission from Butterworth Heinemann Publishers, a division of Reed Educational & Professional Publishing Ltd.)
Fig. 2 Jensen and Michaelsen classification of trochanteric fractures. (Reproduced with kind permission from Parker MJ, Pryor GA. Hip fracture management. Oxford: Blackwell Scientific Publications, 1993.)
the Jensen and Michaelsen (Fig. 2), a modification of the Evans classification, for the trochanteric, and the Seinsheimer for the subtrochanteric fracture (Fig. 3). Both classifications are mainly based on the number of major bone fragments and the location and shape of the fracture lines. Most classifications divide the fractures into stable and unstable fracture configurations or patterns. The following factors cause instability and with that an increase in the rate of fixation failure:
1. According to many classifications, the main key to fracture stability is determined by the presence of postero-medial bony contact, which acts as a support against varus collapse in trochanteric fractures but principally also in subtrochanteric fractures.1–4 2. Another important key to fracture stability is the main direction of the fracture line, especially with a subtrochanteric component. Usually, the fracture extends obliquely from the lesser to the greater trochanter. In reverse obliquity the fracture extends from the lateral cortex, medially and proximally to the lesser trochanter. This fracture type is inherently unstable despite an adequate reduction due to pull of the abductors on the proximal fragment and pull of the abductors on the distal fragment. A transverse fracture in the trans-trochanteric zone has a similar inherent instability. 3. The degree of comminution and the gross displacement of bony fragments are important for stability. The more of these components in the fracture the more will the fracture collapse. 4. The fracture configuration of the lateral cortex of the greater trochanter has been given less importance for fracture stability in the different fracture classifications. A fracture without a lateral cortical spike from the femoral shaft or a fracture with a comminuted area around the entry site of the lag screw gives no lateral support and has an increased risk of medialization5,6 of the femoral shaft due to the pull of the adductors. In summary, the trans-trochanteric zone is the danger area: • An unstable lateral cortex – medialization • An unstable medial cortex – varisation • An oblique reversity – medialization.
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TREATMENT OPTIONS The aim of the surgical treatment is to stabilize the fracture in order to allow early weight-bearing. The stability of the fracture fixation depends on several factors: bone quality, fracture configuration, mode of fracture reduction, implant design and placement of the implant. The surgeon has to consider all these factors but can only control the quality of reduction, implant choice and placement of the implant to give the patient the best conditions for satisfactory healing of the fracture.
SURVEY OF IMPLANT DESIGNS In the 1930s, the first implants to be used for extramedullary fixation of extracapsular hip fractures were the static, rigid or fixed nail plates.1,3 The outcome of the fixation in the stable fracture was often satisfactory. However, in the unstable fracture these implants did not allow impaction of the fracture fragments to occur. As a result, there was an increased stress on the implant. Therefore, it became a race between bony union and failure of the fixation, either by the implant penetrating and cutting out of the femoral head or ultimately undergoing fatigue failure and breaking. The shortcomings of the static implants led to development of new techniques to recreate medial stability. Various types of osteotomies in combination with a static implant were tried with some success. The introduction of sliding implants that allowed impaction of the fracture fragments to occur in the unstable fracture drastically reduced the rate of fixation failure in unstable fractures. These extramedullary dynamic implants have become the gold standard in the fixation of extracapsular hip fractures.1–4 The sliding element is a nail or usually a lag screw, which gives dynamization in the direction of the femoral neck. This dynamization principle is currently used in many implants with synonymous terms such as dynamic hip screw, compression hip screw or sliding hip screw (Fig. 4). Even the dynamic extramedullary implants become static as the fracture line extends more distally into the subtrochanteric region.1,2 Instead of being a loadsharing implant, it turns into a load-bearing one with increased stress on the implant. In an unstable fracture, the risk of fixation failure will increase. In some fracture patterns, e.g. reverse obliquity, the dynamization may lead to an excessive medialization of the femoral shaft with increased stress on the implant resulting in hardware failure (Fig. 5).5,6 Intramedullary (IM) nails1–4 have the advantage of preventing the medialization and of providing better resistance to the strong bending forces in the subtrochanteric region. The IM nails can be divided into cephalo-medullary, with or without interlocking, and
Fig. 4
The sliding hip screw (SHS).
condylo-cephalic types. The most well-known implants in the latter category are the Ender pins, which are inserted in the knee region. Unfortunately, malrotation with distal and proximal migration or penetration of the pins with shortening of the leg often occurred in the unstable fracture requiring reoperations; thus the use of this implant is no longer appropriate. The Zickel nail was one of the first cephalo-medullary nails without interlocking. It has been reported to achieve high union rates but has no rotational stability. The so-called second generation of cephalo-medullary nails has the possibility of distal interlocking, which means control of rotation and of leg length. These include the Gamma nail, the intramedullary hip screw, the Russel-Taylor reconstruction nail and the proximal femoral nail.
THE SLIDING HIP SCREW AND ITS RECENT CHALLENGERS In 1952, von Pohl invented the sliding hip screw (SHS) but it took more than 20 years for this implant to be generally accepted in the orthopaedic community. The SHS is still the most commonly used implant in the treatment of extracapsular hip fractures and every new fixation method has to be compared with this device.1,2 Recently, various modifications and adaptations to this implant, the rigid nail plate and the IM nail, including modifications in reduction techniques, have been introduced with the aim of reducing the risk of fixation failure. However, the role of some of these newer implants is unproven and further research is needed to establish their use. Such devices include the dynamic Martin screw (a dynamic angle-adapted link plate), the percutaneous compression plate, the
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Trochanteric Stabilizing Plate (TSP), the Medoff Sliding Plate (MSP), the Rigidity Augmentation Baixauli (RAB) plate and the interlocking cephalomedullary implants such as the Gamma nail. The last four implants are further discussed.
intensifier.1–4 The lag screw should be placed within 10 mm of the hip joint to obtain a good purchase in the subchondral bone. With the use of a side plate, at least four screws or eight cortices should be fixed distal to the fracture.
The sliding hip screw
Fixation failures
The technique of fracture reduction is similar for most implants but the placement of the implants can differ. For this, I have to refer to operative manuals.1,2
Usually, the SHS, after correct reduction and placement, is adequate in most cases. However, in prospective studies of unstable intertrochanteric fractures, the SHS has a 5–20% rate of fixation failure.7–9 The most common failure is a cut-out of the lag screw from the femoral head, which is often associated with poor reduction or placement of the device.1–4 The main reason is varus collapse of the fracture often due to postero-medial instability and/or excessive femoral medialisation with loss of lag screw slide and poor bone-to-bone contact. If there is a large postero-medial fragment, an attempt should be made to internally fix the fragment in a near anatomic position with a lag screw and/or cerclage wire, which should not interfere with the sliding mechanisms of the implant. Even a non-anatomic reduction is of value as it fills up the postero-medial defect to provide a buttress against varus displacement. However, fixation of the posteromedial fragment may be difficult, particularly if comminution is present. Therefore, in the elderly osteoporotic patient the dissection may do more harm than good by devascularizing the fragments without increasing the stability.1,2 Bone grafting may be used to replace a large bone defect. Augmentation with cement has been advocated as increased resistance to cut-out has been shown biomechanically. However, the distribution of the cement is difficult to control and the cement may interfere with the sliding mechanism of the implant and increase the risk of non-union. Therefore cement augmentation is only indicated in a metastatic fracture.1,2 The deposition of an osteoconductive apatite (Norian SRS) has been tested biomechanically for augmented fracture fixation but its clinical role remains at present uncertain.10 All the above supplementary surgical procedures prolong the operation time and may influence the outcome especially in the elderly patient, as extensive dissection is required, injuring surrounding structures with increased risk of bleeding and infection. Other associated fixation failures are lag screw penetration into the joint, dissociation of the plate from the shaft (by screws breaking or pulling out), implant breakage or bending. The rate of non-union is approximately 2% in intertrochanteric fractures and higher in subtrochanteric fractures.1
Reduction of the fracture A fracture table, which allows biplanar visualization of the entire proximal femur of the supine patient, is needed for both closed and open manoeuvres, which should aim at an anatomical reduction of the fracture. Reduction with varus angulation or posterior sag will result in an incorrect position of the lag screw. Correction of varus angulation will occur with additional traction on the leg, and the use of a periosteal elevator or crutch will correct posterior sag during surgery. Overdistraction of the fracture must be avoided during the operation. If a sliding implant is fixed to the femur with a fracture gap, the dynamic capacity is reduced with an increased risk of converting the implant into a rigid system, because excessive postoperative collapse may exceed the sliding capacity of the implant. This can be avoided by releasing the traction prior to the fixation of the plate to the shaft and manually impacting the distal fragment into the proximal fragment, taking care to maintain the reduction.4 However, a small opening of the fracture medially in a valgus reduction is of value, as subsequent impaction of the fracture will improve the mechanical stability.1,2 Fixation of an extracapsular fracture on the fracture table with the patella pointing to the ceiling avoids any permanent rotational deformity. Controlled medialization of the femoral shaft has been done as a medial displacement osteotomy to increase the stability of the fracture and thus decrease the risk of implant cut-out of the femoral head. However, more recent biomechanical and clinical studies1–4 have shown that this surgical procedure is not appropriate for a SHS and will increase the risk of fixation failure. Anatomic reduction allows greater load-sharing by the bone than medial displacement osteotomy, and with the SHS, stability is not improved by ostetomy. Placement of the implant Correct reduction of the fracture is the prerequisite for accurate positioning of the lag screw. Most surgeons agree that the direction should be at 135º alignment with the femur, and that the lag screw should be placed centrally or slightly inferior on the AP view and centrally on the lateral view using the image
The Trochanteric Stabilizing Plate The medialization of the femoral shaft can become disadvantageous, when it is excessive. It can consume
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all sliding capacity of the lag screw and turn it into a rigid fixation system similar to the rigid nail plate. The stress on the plate will then increase and, if the fracture does not heal in time, the plate will break or dissociate from the shaft, or cut-out may occur (Fig. 5). The reason is a lack of lateral support for the proximal fragment in the trans-trochanteric zone as described earlier. The TSP has been developed for use with the SHS to decrease this medialization. In a comparative study of unstable trochanteric and subtrochanteric fractures, fixation with the dynamic hip screw and the TSP showed a significant decreased sliding of the lag screw but no difference in failure rate compared with the Gamma nail and the compression hip screw.9 This decrease in slide from the TSP is controversial as it can turn the implant rigid, resulting in fixation failure.6 The Medoff Sliding Plate The most dynamic implant of all is the MSP (Fig. 6). It is similar to the SHS but a coupled pair of sliding elements has replaced the side-plate. As an ‘add-on’ plate, it can be combined with any lag screw and its dynamic capacity along both the shaft and the neck of femur gives biaxial dynamisation.7 By using a locking set screw, the sliding along the neck of femur can be stopped and only sliding along the femoral shaft occurs (uniaxial dynamization). The prerequisite for this is the yoking procedure as described below. This allows the barrel-plate to slide inside the side-plate. The idea of an additional dynamization along the femoral shaft with the side-plate of a sliding hip screw came in the 1950s. However, distal enlargement or slotting of the entry hole of the barrel (the yoking procedure) was a prerequisite to allow axial impaction at the fracture site of an intertrochanteric fracture.11 Otherwise, the plate-barrel would impinge on the lateral cortex of the femur, which then obstructs axial compression. A sliding implant with a screw- plate angle closest to the hip joint reaction force, which is 159º to the vertical plane, allows optimum sliding and impaction.3 The dual sliding of the MSP has a barrelplate slide of 180º to the side-plate and a lag screw slide of 135º to the barrel-plate. Theoretically, the advantage of load-sharing is that it gives impaction of the fracture with increased bone-to-bone contact, which improves fracture stability. This should enhance fracture healing and decrease the stress on the implant, thus reducing the risk of fixation failure. As much as 75% of the load applied to a stabilized hip fracture may be absorbed by the bone itself. The greater load sharing capacity of the MSP compared to the SHS has been shown in biomechanical tests; in subtrochantric fractures, 3–4 times higher plate strain was recorded for the SHS compared to the MSP, and in unstable intertrochanteric fractures, the MSP demonstrated more effective stress transfer to the fracture surface of the proximal medial cortex than
Fig. 5 Excessive femoral medialization resulting in non-union, cut-out of lag screw, plate dissociation with breakage of cortical bone screws.
the SHS.6 The reason is probably that the MSP restores medial continuity by decreasing the medial fracture gap by vertical impaction. The indications for the MSP are the unstable intertrochanteric, the combined inter/subtrochanteric fracture and the high subtrochanteric fracture. If the proximal fracture fragment is long and is fixed to the side-plate by the proximal cortical plate screw, no sliding occurs. The MSP gives the surgeon the option of three different dynamization modes to individualize the treatment of extracapsular hip fractures: 1. Uniaxial dynamization is useful in the treatment of pure subtrochanteric fractures, in fractures with a transverse or oblique reversity or without a lateral support in the trans-trochanteric zone. 2. Staged biaxial dynamization, i.e. initial plate sliding followed by later lag screw unlocking, can reduce the degree of femoral medialization and prevent or stop lag screw migration in the head of femur. This mode of dynamization can be of value in fractures with a complete plate slide and risk of lag screw migration, which is most frequent in the combined inter/subtrochanteric fracture (Fig. 6).
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A
B
3. Biaxial dynamization is indicated in the treatment of most unstable intertrochanteric fractures but may also be used in subtrochanteric fractures with lateral support in the trans-trochanteric zone. By using the right dynamization mode of the MSP, it has been possible to reduce the rate of fixation failure to 3% or less in the unstable intertrochanteric fracture (biaxial dynamization), in the high subtrochanteric fracture (uniaxial dynamization) or in the combined inter/subtrochanteric fracture (staged biaxial dynamization).6,7 The Rigidity Augmentation Baixauli plate and indirect reduction technique The RAB plate is similar to the rigid nail plate but is reinforced with a medial strut, which acts as a buttress
C
Fig. 6 The simplified 6-hole Medoff sliding plate (MSP), showing uniaxial dynamization with the (A) maximal amount of plate sliding available; (B) complete uniaxial plate slide; and (C) removal of locking set screw which allows screw in barrel sliding (staged biaxial dynamization).
rod to resist varus collapse (Fig. 7). Mechanical tests with loading to failure showed that the RAB plate was two and three times stronger than that of the Gamma nail and the SHS, respectively.12 The strength of the RAB plate is five times greater with the strut than without it. The indications for the RAB plate are the unstable intertrochanteric and high subtrochanteric fracture but it should not be used if the fracture line goes distal to the lateral end of the strut. The inventor12 states that an anatomical reduction of the fracture, although advisable, is not necessary for its implantation. Neither are complementary techniques necessary, such as reduction and screw fixation of an intermediate fragment or grafting to fill a bone gap. In his retrospective series of 358 patients, 44% had stable fractures, 5% fixation failure and 1% non-union. There was almost no radiologic settling of the fractures in the uncomplicated cases. In a randomized study8 of the RAB plate versus the SHS in 233 patients with unstable trochanteric including high subtrochanteric fractures, 8% fixation failures including non-union were reported. The use of the RAB plate is still experimental and should not be used outside research settings. Indirect reduction and fixation The technique of indirect reduction of fracture fragments with a femoral distractor and the use of a tensioning device to trap and lock the fragments medially has been used in combination with the 95º condylar blade plate for fixation in comminuted
The difficult extracapsular hip fracture
Fig. 7 The rigidity augmentation Baixauli (RAB) plate. (Adapted with kind permission from Baixauli F, Vicent V, Baixauli E et al. A reinforced fixation device for unstable intertrochanteric fractures. Clin Orthop 1999; 361: 205–215.)
Fig. 8 The Gamma nail.
subtrochanteric fractures.13 The blade plate functions as a lateral tension band, when the postero-medial cortex is restored. The vascularity of the fracture fragments is preserved and no bone graft is used. The prerequisite for this technique to work is that bony contact must have been achieved under compression to allow the bone to share the load with the blade plate. Otherwise, the failure rate is high. The Intramedullary Nail Küntscher, in 1939, was probably the first to report on the concept of intramedullay fixation of subtro-
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Fig. 9 Classification of subtrochanteric fractures, used at the Hennepin County Medical Center, showing various methods of treatment. A type-I simple, high fracture involves the lesser trochanter and is treated with a SHS or a second- generation locking nail. In a type-I comminuted fracture that involves the piriform fossa, the SHS is preferred because of the difficulty encountered with insertion of an intramedullary nail. In a type-II simple or comminuted low fracture, a first generation locking nail (with a single locking screw) is used. (Adapted with kind permission from Kyle RF with contributors. Fractures of the proximal part of the femur. J Bone Joint Surg 1994; 76: 924–950.)
chanteric fractures with a ‘Y nail’.3 Since then several types of intramedullary devices have been developed as described above. The latest development in IM nails and challenger to the SHS are the cephalomedullary implants with distal interlocking (Fig. 8). They are also used in intertrochanteric fractures, especially when unstable. These newer implants combine the features of a SHS and an IM nail. Theoretically, they can be inserted in a closed manner with limited fracture exposure, which should result in less blood loss and less tissue damage than occur with the SHS. They are considered more technically demanding to use and have the additional procedure of distal interlocking. In spite of the lack of dynamization along the femoral shaft, there is a high union rate. A biomechanical evaluation of the short Gamma nail in an experimental model of stable and unstable intertrochanteric fractures reported that the Gamma nail transmitted decreasing load to the calcar with decreasing fracture stability.4 Virtually no strain on the bone was seen in four-part fractures with the posteromedial fragment removed. Insertion of the distal locking screws did not change the pattern of proximal femoral strain. Due to the low compressive load on the calcar, an increased load occurs at the tip of the nail. This increases the stress on the bone around the distal tip of the implant. However, with a long stem this load is redistributed throughout the distal femur without significant increase of the distal femoral stress. There are specific problems with the IM nails during surgery and later.1,2 Intraoperative fracture of the femur
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Table 1 Survey of design and function (*) of the SHS and some challengers, including fixation failure
SHS (•) w. TSP (•) MSP – Biaxial – Unaxial – Staged RAB Gamma nail (•)
Special feature
Prevents medialization
Dynamic capacity
Load sharing
Fixation** failure (%)
Randomized trials
None Lateral buttress
No ++
++ +
++ +
0–20 6
Many None
Unlocked Locked Secondary unlocking Medial buttress Distal interlocking
+ +++ ++
+++ ++ ++(+)
+++ ++ ++(+)
0–3 0–7 –
Few Few None
+++
No
No
6–8
Few
++(+)
+
+
2–12 (³)
Several
* The graduated system is based on theory and the differences in grading may not correlate to quantity or quality but is an attempt to separate the design and function between the different implants ** May include stable fractures (•) No dynamic capacity or load sharing in the subtrochanteric region (³)Includes later fracture of femur
have been reported in approximately 3% during the insertion of the nail. Often inadequate reaming of the femur is the cause. Late femoral shaft fractures at the distal tip of the nail have been reported to occur in about 5% with the short Gamma nail. The stress riser effect of inadequate drilling of the screw holes may increase this risk. In a meta-analysis of the Gamma nail versus the dynamic hip screw for extracapsular hip fractures, the Gamma nail had a significantly increased risk of femoral shaft fractures but there was no difference in the lag screw cut-out.14 Improvements in the construction of the implant, the operative technique and development of a long stem have attempted to decrease this risk. A classification system and algorithm for the treatment of subtrochanteric hip fractures including concurrent ipsilateral femoral shaft fractures3 has been developed at the Hennepin County Medical Center (Fig. 9). At the Centre for Traumatology and Orthopaedics in Strasbourg, the short and the long Gamma nail are used to treat all trochanteric and trochantericdiaphyseal fractures independent of the complexity of the fracture and without any complementary fixations like banding, screwing, bone grafting or cement.
and of the design of different implants. After mastering the surgical technique, the thoughtful orthopaedic surgeon can choose an adequate fixation method for the specific fracture type to achieve the best result possible (Table 1). Randomized studies, comparing the SHS as the reference standard with new implants, are of utmost importance. However, it may be difficult to give such a valid statement unless larger number of patients are studied. The goal of treatment is to be able to mobilize the patient fully weight-bearing immediately after surgery. It should be possible with current surgical techniques and implants, even in the most difficult extracapsular hip fracture. Failure to achieve this should be termed a failure of treatment, and is not acceptable in elderly patients, who do not tolerate bed rest, restricted weight bearing, prolonged surgery or complications of surgical treatment. Acknowledgements The author is grateful for constructive criticism from Martyn J. Parker, MD, FRCS (Edin), Orthopaedic Research Fellow, Peterborough District Hospital, Peterborough, UK.
Endoprosthetic replacement Arthroplasty is generally not indicated and its role remains unproven. However, in the very comminuted intertrochanteric fracture a primary endoprosthetic replacement has been advocated.15 The indication for a primary arthroplasty is stronger in the combined intra/extracapsular hip fracture, where the risk of non-union and femoral head collapse is high.
HIP FRACTURE PHILOSOPHY I think it is very important to have a basic understanding of fracture configurations, of biomechanics
REFERENCES 1. Parker MJ, Pryor GA. Hip fracture management. Oxford: Blackwell Scientific Publications 1993. 2. Parker MJ, Pryor GA, Thorngren K-G. Handbook of hip fracture surgery. Oxford: Butterworth-Heinemann, 1997. 3. Kyle RF with contributors. Fractures of the proximal part of the femur. J Bone Joint Surg 1994; 76: 924–950. 4. Koval KJ, Zuckerman JD. Hip Fractures: II. Evaluation and treatment of intertrochanteric fractures. J AAOS 1994; 2: 150–156. 5. Parker MJ. Trochanteric fractures. Fixation failure commoner with femoral medialisation, a comparison of 101 cases. Acta Orthop Scand 1996; 67: 329–332. 6. Lunsjö K, Ceder L, Tidermark J et al. Extramedullary fixation of 107 subtrochanteric fractures. A randomized multicenter trial of the Medoff sliding plate versus 3 other screw-plate systems. Acta Orthop Scand 1999; 70(5): 459–466.
The difficult extracapsular hip fracture 7. Watson JT, Moed BR, Cramer KE, Kargas DE. Comparison of the compressive hip screw and the Medoff sliding plate for intertrochanteric fractures. Clin Orthop 1998: 348: 79–86. 8. Buciuto R, Uhlin B, Hammerby S, Hammer R. RAB- plate vs Richards CHS plate for unstable trochanteric hip fractures. A randomized study of 233 patients with 1-year follow-up. Acta Orthop Scand 1998; 69: 25–8. 9. Madsen JE, Naess L, Aune AK, Alho A, Ekeland A, Stromsoe K. Dynamic hip screw with trochanteric stabilizing plate in the treatment of unstable proximal fractures: a comparative study with the Gamma nail and compression hip screw. J Orthop Trauma 1998; 12: 241–248. 10. Goodman SB, Bauer TW, Carter D et al. Norian SRS cement augmentation in hip fracture treatment: laboratory and initial clinical results. Clin Orthop 1998; 348: 42–50. 11. Jarrett PJ, Fleming LL, Whitesides Jr, TE. The stable internal fixation of peritrochanteric hip fractures. In:
12. 13. 14. 15.
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Fractures of the hip. AAOS Instructional Course Lectures 1984; 33: 203–218. Baixauli F, Vicent V, Baixauli E et al. A reinforced fixation device for unstable intertrochanteric fractures. Clin Orthop 1999; 361: 205–215. Kinast C, Bolhofner BR, Mast JW, Ganz R. Subtrochanteric fractures of the femur: results of treatment with the 95 degrees condylar blade-plate. Clin Orthop 1989; 238: 122–30. Parker MJ, Pryor GA. Gamma versus DHS nailing for extracapsular femoral fractures. Meta-analysis of ten randomised trials. Int Orthop 1996; 20: 163–68. Staepperts KH, Deldycke J, Broos PLO, States FFGM, Rommens PM, Claes P. Treatment of unstable peritrochanteric fractures in elderly patients with a compression hip screw or with the the Vandeputte (VDP) endoprothesis: a prospective randomised study. J Orthop Trauma 1995; 9: 292–7.