AOT Posttrauma Deformities book sample

Table of contents Foreword

(René K Marti)

Foreword

(Christian van der Werken)

Introduction (Ronald J van Heerwaarden) Contributors

1

vi viii x xiii

Principles part

1

1.1

Posttraumatic deformities and osteotomies

1.2

General considerations on indications, types of osteotomy, bone healing, and methods of fi xation

17

1.3

Diagnostics and planning of deformity correction: formation of a surgical plan

33

2

Manual part

57

3

Clavicle 2.1

Clavicle

Femur 66

Humerus 2.2

Humerus, proximal

78

2.3

Humerus, distal

114

2.4

Elbow joint

128

Radius and ulna 2.5

Radius and ulna, proximal and shaft

146

2.6

Radius and ulna, distal

184

Pelvis/hip joint 2.7

Pelvic ring and acetabulum

228

2.8

Hip joint and femur, proximal

276

2.9

Femur, proximal

318

2.10

Femur, shaft

330

2.11

Femur, distal

370

2.12

Knee joint

428

Tibia 2.13

Tibia, proximal

478

2.14

Tibia, shaft

546

2.15

Tibia, distal

592

Ankle and foot 2.16

Ankle

616

2.17

Midfoot and hindfoot

650

Appendix Glossary

701 702

Abbreviations

704

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Authors

1.1 1

Ronald J van Heerwaarden, René K Marti

Posttraumatic deformities and osteotomies History

2

The history of osteotomies is really the history of descriptions of deformities starting with Hippocrates. Up to Medieval times the society did not feel responsible for those who suffered from deformities, as diseases and deformity were considered to be punishments for sin. Unfortunately, in some societies in large parts of the world this is still true today. Considering corrections of deformities, only few references are to be found in the older literature. Some texts described how malunited bones should be separated using chisels, however, it took until the 19th century before the word “osteotomy” was first used to describe the cutting of bone. Not until the introduction of antiseptic surgery were osteotomies made popular by a select group of surgeons. At the start of the 20th century it was fi rst acknowledged that malunited fractures impaired joint function and that together with limb shortening a posttraumatic deformity resulted in the decrease of the patient’s relative fi nancial economic value.

a

b

Causes of posttraumatic deformities

A posttraumatic deformity is the result of the treatment of the sequelae of specific traumas to the locomotor system.

Knowledge of the initial bone and soft-tissue lesions as well as the specific treatment—whether conservative or operative— and postoperative treatment will help to fi nd the cause of the deformity and is mandatory for decision making, concerning type and technique of secondary reconstructions. Regarding bone deformities the cause of the deformity is often found in the initial choice of fracture treatment. This does not necessarily mean that the wrong treatment had been chosen as sometimes decisions have to be based on factors that may interfere with optimal fracture treatment (Fig 1.1-1).

c

Fig 1.1-1a–c Severe soft-tissue lesions interfere with optimal fracture treatment. a Comminuted type C3 fracture of the proximal tibia. b Lag screw and external fi xation, no anatomical reconstruction. c Vital granulation tissue after debridement of the tibial head, before split skin grafting as performed earlier to repair the skin defect over the distal femur.

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1

Principles part

Insufficient stability of fixation and wrong postoperative treatment may be a secondary cause of a malunion (Fig 1.1-2).

Unfortunately, however, the surgeon specialized in the treatment of posttraumatic deformities is also faced with malunions that are the result of insufficient fracture treatment. In this respect the importance of understanding the principles of fracture treatment, normal anatomy, and biomechanics of the locomotor system cannot be stressed enough. Readers of this book should already be acquainted with such knowledge from textbooks and specific courses.

3

Characteristics of posttraumatic deformities

Posttraumatic deformities differ significantly from deformities acquired through growth as limb anatomy and function most often were normal before the trauma. In contrast, in deformities resulting from growth the function may be normal whereas abnormal anatomy causes unphysiological loading. Often adaptation to the unphysiologic loading occured through compensatory growth of bone and soft tissues or by compensatory motions of the neighbouring joints. In posttraumatic deformities in children a similar mechanism of compensatory growth may have occurred as a result of malunited fractures. A prerequisite is, that the growth plates still function normally and that growth stimulation and potential suffice, depending on age and the location of the deformity.

In this book the surgical correction of malunited fractures is described in adults and in some cases in children after closure of growth plates. Functional deficits in these patients can often be attributed to the malunited bone, as normal muscle and joint function depends on normal anatomy of the bone.

a

b

Fig 1.1-2a–b Internal fi xation without anatomical reduction. a Fracture healing with narrowing of the tibial head, valgus and intraarticular malunion of the lateral condyle. b The lateral femoral condyle dives into the depressed tibial head, resulting in a bony pivot shift.

4

Terminology of posttraumatic deformities

A posttraumatic deformity may be the result of a bony deformity considered sufficient to produce a functional deficit including angulation, rotation, translation, and limb shortening, but may also be the result of joint malfunction or contracture.

Angular deformities present themselves either in the frontal plane causing valgus or varus of the affected limbs, or in the sagittal plane causing a recurvatum or procurvatum deformity. A combination of a frontal and a sagittal plane angular deformity has its maximum angulation in an oblique plane.

Translation of a segment may produce a deformity without angulation, and can occur in both, the frontal and sagittal

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1.1

Posttraumatic deformities and osteotomies

planes. Rotation of a segment around its axis causes a rotational deformity, while shortening clinically presents as a limb length discrepancy. These deformities on their own are termed uniplanar deformities. If a deformity in the same bone segment coexists in two planes or in more than two planes, these are termed biplanar and multiplanar deformities, respectively. The site of the deformity may be at the diaphysis, metaphysis, or at the level of the joint, and may either be unifocal or multifocal if the deformity coexists with another, at more than one level, within the same segment of bone. Unifocal or multifocal deformities are also referred to as uniapical or multiapical deformities.

5

increase in complexity as the aims of treatment become more complex: from simple deformity correction, to deformity correction plus lengthening to deformity correction plus lengthening plus correction of contracture (Fig 1.1-3).

To our knowledge only one classification system has been designed, which can serve as the basis for treatment, prognosis, and the comparative evaluation of results of limb deformity corrections. The Sheffield Classification [1] is used to describe the major primary operative intervention and includes a location specific malunion description based on the Müller AO Classification of fractures.

Classification of posttraumatic deformities

The general classification of posttraumatic deformities is primarily based on the localization, ie, intraarticular, metaphyseal, and diaphyseal. Furthermore, deformities can be defined as simple (one plane) or complex (several planes and translation).

Classification systems can be of great help to analyze and describe specific bone conditions in a uniform way. For decades the Müller AO Classification of fractures has been helping surgeons to understand fracture types and has also led to standardized advice on how to treat fractures. This allows comparison of treatments for specific fracture types.

Classifications that describe specific types of malunited fractures are rare. For some locations, eg, the proximal humerus and the calcaneus a classification of specific malunion types has been established and based on this differentiated treatments have been advised. In this book these specific classifications, if available, are described in the introductions to the case presentations of the different locations. For the treatment of posttraumatic deformities it is of great help to the surgeon if a classification also includes techniques for deformity correction. Moreover, the aims of treatment should be included as the techniques of deformity corrections

Fig 1.1-3 Posttraumatic deformity: shortening, equinus, and varus deformity of the ankle and hindfoot with inverted midfoot.

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6

Principles part

Effects of posttraumatic deformities

In order to understand the effects of malunions in the upper and lower extremity one should have a thorough knowledge of normal anatomy and biomechanics of limb function. In this book, the cases illustrating the effects and corrective treatments of posttraumatic deformities at specific locations are preceded by an introduction. These introductions offer information on how these posttraumatic deformities affect the specific regions of the locomotor system. In some cases, literature references as well as recommendations for further reading may also be found.

The effects of posttraumatic deformities are often multifactorial.

Fractures almost always result in alterations of bone and soft tissues even in cases of optimal fracture treatment. Depending on type and location of malunions these small alterations,

whether in angulation, length, rotation or translation, may be well tolerated. Beside the magnitude of the deformity local muscle strength, ligamentous laxity, cartilage integrity and range of motion of the joints of the affected extremity will contribute to the effect of the deformity. Multiple corrections may be necessary to achieve a good result (Fig 1.1-4).

Short-term effects of malunions may cause symptoms immediately after fracture healing. They only arise when the deformity is severe and compensatory limits in adjacent joints are exceeded. The long-term effects of malunions may present with delayed-onset symptoms often related to joint overload and deterioration (Fig 1.1-5). A causal relationship between joint deterioration and altered mechanical loads resulting from malunion is sometimes hard to prove although an increasing number of animal, cadaveric, and clinical studies support this hypothesis.

a

b

c

d

Fig 1.1-4a–d a Severe planovalgus foot. b Valgus leg alignment. A triple fusion adapted to the valgus knee would need a further correction in case of a later total knee replacement. c The opening-wedge varus tibial head osteotomy must be the first step in the operative treatment. d Normal leg and foot alignment after tibial head varization and triple fusion.

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1.1

Posttraumatic deformities and osteotomies

The effects of bone deformities and resulting symptoms that lead to the selection of patients who need a correction for a posttraumatic deformity are diverse. In a previous publication an attempt was made to describe the main factors that influence the selection of patients for corrective osteotomies [2]. These factors, presented in Table 1.1-1, are illustrated in Fig 1.1-6 and Fig 1.1-7 and also apply to the cases presented in this book.

Main factors influencing patient selection for corrective surgery of a posttraumatic deformity 1

Unphysiological mechanical loads on the joints

2

Functional aspects

3

Effects on capsuloligamentous structures of adjacent joints

4

Morphologic condition of bone, cartilage, and soft tissue

5

Subjective complaints

6

Cosmetic effects

Table 1.1-1 Main factors influencing patient selection for corrective surgery of a posttraumatic deformity.

Fig 1.1-5 This severe malunion first developed symptoms 25 years after the accident.

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Principles part

a

b

415 mm

412 mm

Fig 1.1-7 Clinical picture of the varus of the left elbow and the loss of extension in a 19-year-old female. All factors influencing patient selection for corrective surgery are present.

96° 93° 100°

341 mm

c

14°

88°

d 351 mm

Fig 1.1-6a–d Short-term effects after a proximal tibia fracture. A severe posttraumatic valgus alignment causes symptomatic unphysiological mechanical loading of the lateral knee compartment, ankle and subtalar joint (factor 1), gait abnormality and knee instability (factor 2) (a). Medial capsuloligamentous overload can be unloaded by varus stress (factor 3) (b, c). Concommitant cartilage damage of the lateral compartment causes knee pain and swelling as well as a decrease in daily activities (factor 4 and 5).

Furthermore, the cosmetic effect is unacceptable in a 22-year-old female (factor 6) (d).

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1.1

Posttraumatic deformities and osteotomies

The effect of a malunion is also related to specific aspects of the bony deformity. In regard to the relative importance of specific factors one should understand that for example the absolute value of an angular bone deformity alone cannot be considered the single most important factor. Associated bone translation and the level of the deformity are other crucial aspects that must be taken into account. Deformities that are located near the elbow or knee have the largest effects on the

mechanical limb axis, whereas deformities near the shoulder or hip cause less mechanical axis deviation but may result in large limb-length discrepancies. Although angular deformities near the wrist or ankle joints may cause only small mechanical axis deviations and length discrepancies, the joint line orientations may be severely abnormal. In this respect nomograms can be used to predict the effects of osteotomy on limb length caused by malunited fractures [3] , (Fig 1.1-8, Fig 1.1-9).

Leg length (% true length) 97

98

99

100

Deformity (deg) 0 10 20 30 40

-25 -20 -15 -10 -5 5 10 15 20 25

50 60 70 80 90

a

100

Fig 1.1-8a–b Nomograms of the effects on leg length of malunion level and angulation in the sagittal plane (a). The lines from the center out represent 5° steps of the deformity (vertical axis percentage of limb length as 10% steps; horizontal axis determines effect of deformity) (redrawn from [3]).

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Principles part

Leg length (% true length) 96

97

98

99

100 101 102 103

0 10 20 30 40

Deformity (deg) -25 -20 -15 -10 -5 5 10 15 20 25

450 mm

50 808.1 mm

60

92° 70 80° 80 345 mm

90 b

Varus

Valgus

0°

100

Fig 1.1-8a–b (cont) Nomograms of the effects on leg length of malunion level and angulation in the frontal plane (b). The lines from the center out represent 5° steps of the deformity (vertical axis percentage of limb length as 10% steps; horizontal axis determines effect of deformity) (redrawn from [3]).

a

b

Fig 1.1-9a–b Malunited distal tibial fracture before (a) and after (b) closingwedge corrective ostetotomy. Leg length has changed only 1 mm after the reconstruction of the ankle joint orientation.

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1.1

7

Posttraumatic deformities and osteotomies

Osteotomies

An osteotomy can be defined as the correction of a bone aimed at restoration of normal bone anatomy, joint anatomy, and limb function. An osteotomy may also have the aim to unload joints, or parts of joints, or simply straighten a limb in order to prevent progression of posttraumatic cartilage damage or osteoarthritis of the neighboring joints. Osteotomies may be performed to change length (lineal osteotomy), rotation (torsional osteotomy), displacement (translational osteotomy), or angulation (angular osteotomy) of the bone. Often more than one effect is desired and a more complex osteotomy has to be performed.

In this book a wide variety of osteotomies to correct posttraumatic deformities at almost all locations of the locomotor system is presented. Although the type and complexity of the osteotomies are different depending on the initial deformity and location they can be classified essentially into six different types ( Table 1.1-2). The four basic types of osteotomies are: closing-wedge, opening-wedge, step-cut, and arcuate type.

For the closing-wedge and opening-wedge types the effect of the osteotomy depends on the orientation of the cuts relative to the shaft axis of the bone. This adds two other types to the aforementioned four osteotomy types: closingwedge and opening-wedge osteotomy with cuts oblique to the shaft axis.

7.1

Osteotomy methods

There are different methods of cutting the bone. Traditionally the bone cut was made with a sharp chisel or osteotome.

Choosing an instrument with a long stem or shaft will give better control while performing the osteotomy. Another method is to use a motorized saw to cut the bone. Preferably a saw is chosen with variable deflection and adjustable speed.

This will give the surgeon maximum control of saw blade excursion and saw depth. For every operation a new sawblade should be used. Only sharp instruments will create accurate bone cuts and less heat will be produced during cutting of the bone. To further prevent heat necrosis the sawblade should be irrigated and an intermittent cutting or start-stop technique can be used. Tissue spreaders and tissue retractors are to be used in order to prevent the soft tissues from being damaged during the osteotomy.

Besides performing osteotomies with osteotomes or a motorized saw other devices can be used, eg, a burr or a Gigli saw.

These less well-known osteotomy techniques are often used in external fixator (assisted) corrections, eg, the multiple drill hole technique and percutaneous Gigli saw osteotomy. To study these techniques, the reader is referred to other textbooks.

Beside the six basic types of osteotomies described above a miscellaneous group including different osteotomies may be defi ned containing specific types of displacement osteotomies and osteotomies for corrective lengthening with callotasis.

These techniques are also described in the case presentations in the second part of this book.

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Principles part

Osteotomy type

Effects

1 Closing-wedge osteotomy with transverse cuts made perpendicular to the shaft axis

Shortening of bone length by half the length of the base of the wedge that is taken Leaves surfaces perpendicular to the shaft axis, allowing for correction of rotational deformities

Example

25° 6 mm

25° 2 Closing-wedge osteotomy with cuts oblique to the shaft axis

Corrections in one plane but by sliding of cut surfaces also small corrections in another plane and rotations possible Additional possibility for bone lengthening, intrinsic rotational stability, possibility for lag screw fixation crossing the osteotomy

3 Opening-wedge osteotomy with a transverse cut aimed at the apex of the deformity

Allows for correction in all three planes and lengthening of the bone (if full contact between surfaces of the cut does not need to be maintained) Lengthening of the bone to half the length of the base of the wedge (if contact between surfaces of the cut is maintained)

Table 1.1-2

Basic types of osteotomies and their effects.

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1.1

Posttraumatic deformities and osteotomies

Osteotomy type

Effects

4 Opening-wedge osteotomy with cut oblique to the shaft axis

Same advantages as 3

Example

Additional lengthening of bone length without loss of contact of surfaces of the cut possible Lag screw fixation of interpositional bone graft in open wedge possible

5 Step-cut or distraction osteotomy

For cases with significant displacement and angulation Allows for correction in all three planes and lengthening of the bone

6 Arcuate or dome osteotomy

Allows for angular correction in one plane and displacement correction at perpendicular plane of the bone Alignment of surfaces of the cut after correction enhances stability

175°

Table 1.1-2

(cont)

Basic types of osteotomies and their effects.

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7.2

Principles part

Osteotomy equipment

In Fig 1.1-10 examples of osteotomy sets are displayed.

Standard equipment should consist of osteotomes, K-wires, adjustable power saw, pointed reduction forceps, tensioning device, triangular angle guides, bone spreaders, and bone holding forceps. The standard osteotomy set may be extended by calibrated osteotomes, sawblades, spreaders, and goniometers, impaction chisels, screw-tipped K-wires, alignment bar, and curved gouches and impactors for intraarticular reconstructions.

Osteotomes are not only used to cut the bones but also to gradually spread the bone in incomplete opening-wedge osteotomies and to weaken the opposite cortex in incomplete closing- and opening-wedge techniques. K-wires are also used for different purposes: as references in the bone beside the site of osteotomy for position control, to mark the direction of the sawcuts, to measure the saw depth after fluoroscopic control, to guide the sawblade during the osteotomy and as temporary

a Fig 1.1-10a–b

fi xation after bone correction. Sawblades of different thickness may be chosen; thick sawblades are stable and will not bend during cutting whereas a thin sawblade will cause less bone loss during cutting. Using a calibrated saw blade will give the surgeon additional depth control.

If no calibrated sawblades are available a simple ruler and a permanent marker may be used to mark the saw depth on the saw blade.

For accurate correction planning and measurement during surgery triangular angled guides and goniometers are available. Rigid guiding rods are used to check whole leg alignment simulating weight-bearing conditions. Bone spreaders of different sizes as well as calibrated bone spreaders may be used for opening-wedge osteotomies. In closing-wedge osteotomies an impaction osteotome is helpful for impaction of spongious bone at the hinge point before closing the wedge.

b Standard osteotomy set (a) and extended osteotomy set (b).

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1.1

Posttraumatic deformities and osteotomies

Pointed reduction forceps can be used either for protection of the cortex near the hinge point of an opening- or closingwedge osteotomy to prevent displacement, or to reduce and compress osteotomized bone parts. Tensioning devices can be used for osteotomy compression as well as controlled distraction of the osteotomy.

For intraarticular osteotomies special angled gouches, osteotomes and impactors are used to osteotomize a malunited depressed articular fragment and reduce the fragment to normal articular height.

8

Bibliography

[1] Ali F, Saleh M (1999) The development, validation and clinical usage of a new classification for limb reconstruction surgery.

J Bone Joint Surg Br; 81: Orthop Proc III: 279.

[2] Hierholzer, G, Müller KH (1985) Corrective Osteotomies of the Lower Extremity after Trauma. Berlin Heidelberg New York: Springer-Verlag.

[3] Wade RH, New AM, Tselentakis G, et al (1999) Malunion of the lower limb. A nomogram to predict the effects of osteotomy.

J Bone Joint Surg Br; 81(2):312–316.

9

Suggestions for further reading

Marti RK (2007) Malunion. Rüedi TP, Buckley RE, Moran CG (eds) AO Principles of Fracture Management. 2nd expanded ed.

Stuttgart New York: Georg Thieme Verlag.

Mast J, Jakob R, Ganz R (1989) Planning and Reduction Technique in Fracture Surgery. Berlin Heidelberg New York: Springer Verlag Berlin.

Paley D (2003) Principles of Deformity correction.

Browner BD, et al (eds), Skeletal Trauma. Basic Science, Management and Reconstruction. 3rd ed. St. Louis: Elsevier Science (USA).

Probe RA (2003) Lower extremity angular malunion: evaluation and surgical correction. J Am Acad Orthop Surg; 11(5):302-311.

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Principles part

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Authors

1.2 1

René K Marti, Ronald J van Heerwaarden, Christian van der Werken

General considerations on indications, types of osteotomy, bone healing, and methods of fixation Introduction

In general, malunions of the upper extremities are better tolerated than in the lower extremities and will not lead to early arthritic changes. The main indications for corrective surgery are pain, instability, loss of function, and sometimes cosmetical aspects. Malalignment and shortening of a weightbearing lower extremity will lead to neighbor joint overuse, contracture, and finally arthritic changes. Therefore, correction osteotomies are indicated to avoid the need for early joint replacements. This is certainly valid for deformities near the knee and ankle joint.

It is beyond the scope of this book to note specific values in, eg, angulation of deformities that define the indication for correction; furthermore it should be noted that in case some general guidelines are given, the normal values of bone or limb shape may vary due to geographical or racial differences.

2 2.1

Indications Upper extremity

Angular deformities, translation, shortening, and even malrotation of the humerus are in general well tolerated. However, this is not true for the forearm. The main indication for correction of malunions of the upper extremity is a limited function as a result of malunion, joint contractures, instability, or nerve palsy. Soft-tissue contractures cause functional length differences in upper extremities. Flexion contractures of shoulder, elbow, or wrist joints will all cause a relative shortening of the arm, which should be treated by soft-tissue releases and joint arthrolysis and only in exceptional circumstances by corrections of the bone. The osteotomy techniques used for deformity corrections in the upper extremity are similar to the techniques used for lower extremity corrections. These techniques will be described in detail in the upper extremity cases presented in the manual part of this book.

2.2

Intraarticular malunion

Painful and disabling articular incongruence leading to progressive arthritic changes with instability is an absolute indication for surgery, particularly in the lower extremity. The decision as to whether a secondary intraarticular reconstruction, an extraarticular correction osteotomy, or a combination of both, an arthrodesis, or an arthroplasty should be performed depends on joint and extremity function, age of the patient, bone and soft-tissue conditions, and socioeconomic factors (Fig 1.2-1, Fig 1.2-2, and Fig 1.2-3). Reconstruction of joint alignment is the secret of long-term success of osteotomies for any intraarticular malunion. Reconstruction of (near) normal joint line alignment relative to the ground and the neighboring joints is specifically important in the weight-bearing lower extremities.

2.3

Lower extremity angular malunions

The indication to correct a lower-leg angular deformity is based on clinical symptoms and, especially among younger patients, on the natural history of an untreated malunion. The origin of symptoms is often multifactorial and may or may not be localized at the level of the resulting articular malalignment (Fig 1.2-3). Ligamentous laxities, muscular weakness, meniscus tears, and unicompartimental articular cartilage degeneration may present as first signs of a leg inable to cope with a posttraumatic deformity. Back pain secondary to a scoliosis compensating for leg-length difference and subtalar osteoarthritis secondary to angular malunions of the lower leg are examples of failure caused by compensating mechanisms at some distance from the deformity.

There are no absolute indications for corrections of an angular deformity in the frontal or sagittal plane, based on the degrees of deviation different from normal. In general, varus knee or ankle angles greater than 10° need correction and the same is valid for valgus of more than 15° or medial shift of 2 cm or more. In the sagittal plane indications for corrections are based on the function of the joint. Full knee extension and a plantigrade foot are more important for the final functional result than an alignment based on x-rays.

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1

Principles part

In the preoperative planning it must be considered that corrections of severe angular deformities or joint contractures

a

a

b

lead to lengthening or shortening of the leg (Fig 1.2-4). This is especially true for deformities at the level of the hip joint.

Fig 1.2-1a–c Severely multifragmentary intraarticular distal humeral fracture (a) resulting in a malunion with severe joint malalignment (b) and planning for combined intraarticular and extraarticular correction to realign the limb and elbow joint line (c) (see case 2.4.2 Correction of intraarticular malunion of the distal humerus).

c

b

c

d

Fig 1.2-2a–d AP and lateral view of a malunited tibial head fracture producing a bony pivot shift (a–b). Radiological (c) and clinical presentation (d) 20 years after a complex intraarticular tibial head reconstruction (see case 2.13.7 Opening-wedge varization, intraarticular, and monocondylar osteotomy for a malunited tibial head fracture).

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1.2

General considerations on indications, types of osteotomy, bone healing, and methods of fixation

a

b

Fig 1.2-4a–b A planned leg lengthening can be achieved by a combined opening- and closing-wedge osteotomy of a severe varus malunion of the proximal femur (see case 2.8.6 Valgization intertrochanteric osteotomy for a malunited lateral femoral neck fracture).

Fig 1.2-3 An adduction/contracture of the hip leads to a lateral displacement of the femoral head, a valgus knee, and a compensatory varus of the ankle and hindfoot (arrows).

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2.4

Principles part

Rotational malunions

In closed fracture treatment as well as in surgical treatment of fractures, angular alignment may be restored, however, restoration of rotational alignment is sometimes overlooked.

Rotational malunions secondary to intramedullary nailing of long bones are often found as intraoperative control of rotation remains technically difficult (Fig 1.2-5).

Malrotations of the femur are better tolerated than tibial rotational malunions. The normal hip joint is able to compensate for a 20° loss of internal or external rotation. The fully extended hip should have at least 20° of external and internal rotation range of motion to allow for normal walking. In posttraumatic deformities resulting in restricted hip joint rotation, forces acting on knee, ankle, and foot joints may cause symptoms. Changes of more than 10° of the physiological external rotation of the tibia are not well tolerated because knee and ankle joints act essentially as hinges and therefore cannot compensate for rotational malalignment. For example the loss of the physiological external rotation position of the foot after a malunited tibia fracture severely compromises normal walking ability. In this respect, internal rotation malunion of the tibia is tolerated even less.

Symptoms related to torsional deformities of the lower extremity in the hip region are groin pain, impairment of hip mobility and instability of the hip. At the region of the knee patellofemoral pain and instability often occur whereas at the ankle joint gait abnormalities, frequent stumbling and fatigue complaints may point in the direction of a torsional deformity.

Pronounced internal rotation malunions may lead to overuse of the patellofemoral and the tibiofemoral joint whereas external rotation malunions are badly tolerated by the midfoot.

Depending on the local bone configuration and bone quality malrotations can be corrected at the level of the diaphysis or metaphysis. The limit of metaphyseal correction is ca. 35°. In large rotational corrections extensor mechanism function, neurological and vascular problems, and compartment syndromes should also be considered.

2.5

Leg-length discrepancies

Because of the multifactorial causes for leg-length differences the indication to perform an operative correction of a leglength discrepancy is never absolute and cannot be expressed in centimeters. However, in general, in patients with leg-length differences of more than 2 cm not due to correctable softtissue contractures of the limb surgical interventions may be considered.

When analyzing and treating leg-length differences two important factors should be considered first before a lengthening or shortening procedure is performed; first whether the leg-length difference is caused by a bony deformity or by softtissue contractures, and second what the remaining length difference will be after correction (straightening) of an angulated and shortened bone.

Fig 1.2-5 Right knee and foot externally rotated after severe rotational malunion of a femur fracture (see case 2.10.5 Femur shaft derotation osteotomy for severe rotational malunion).

In the lower limb adduction and abduction contractures around the hip are known causes for relative limb shortening or lengthening, respectively. Flexion contractures around the knee cause a shortening of the leg whereas achilles tendon shortening causes a relative lengthening of the leg. In these

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1.2

General considerations on indications, types of osteotomy, bone healing, and methods of fixation

cases muscle and tendon releases with or without arthrolyses are the method for treatment of leg-length differences.

of intertrochanteric shortening on one side and diaphyseal lengthening on the other is a very elegant method of correcting leg-length differences of up to 8 cm.

The intertrochanteric shortening osteotomy of up to 4.5 cm (Fig 1.2-6a–b) has a low complication rate. The same is true for the intertrochanteric one-step lengthening of up to 3.5 cm (Fig 1.2-6c–d), which however is only indicated when other corrections at hip level are also necessary.

In general, acute or one-step procedures are less dependent on the cooperation and compliance of the patient and of the infrastructure of the outpatient department. Most femoral deformities and small leg-length discrepancies can be corrected acutely due to relatively bulky musculature, generous compartments and lax neurovascular structures present in the thigh. However, significant acute shortening or lengthening procedures at the level of the knee and tibia are risky (due to quadriceps insufficiency, neurological damage, or compartment syndromes) and therefore callus distraction is the method of choice to equalize leg-length discrepancies, certainly at the level of the tibia.

For diaphyseal lengthening of more than 5 cm, callus distraction using the original Ilizarov frame or less bulky unilateral external fixators is often the method of choice. Gradual lengthening with callus distraction (Fig 1.2-7) is followed by a period of bone healing and remodeling before the external fixator can be removed. Secondary percutaneous plating may significantly shorten the bone-healing time. Alternatively, the combination

a

b

c

Fig 1.2-6a–d Planning of intertrochanteric shortening (a–b). Intertrochanteric lengthening osteotomy (c–d) (see case 2.10.2 Leg-length equalization by diaphyseal lengthening and contralateral subtrochanteric shortening and case 2.8.3 Correction of malrotation, shortening, and varus deformity after a malunited femoral shaft fracture).

d

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Principles part

Disadvantages are a larger exposure and a shortening of the bone. Opening-wedge techniques can be performed without any displacement leaving the opposite cortex intact. The inserted bone graft creates additional “intrinsic stability” and fixation is often possible with minimally invasive techniques.

Oblique, single-cut osteotomies allow correction of length, angulation, translation, and to some degree even rotation.

The same is valid for the distraction osteotomy. Dome osteotomies are reserved for deformities in the metaphysis, near the joint.

a Fig 1.2-7a–b Clinical (a) and radiological (b) example of callus distraction with an unilateral external fixator (see case 2.10.2 Leg-length equalization by diaphyseal lengthening and contralateral subtrochanteric shortening and case 2.12.4 Multiple corrections of posttraumatic deformity and leg-length discrepancy due to growth disturbance).

Pure mechanical correction of an angular deformity should be planned at the center of rotation of angulation. Although this might be a level at which soft-tissue problems exist and sclerotic bone may also cause problems for fixation and healing. Osteotomy in a better vascularized area away from the center of the deformity may give a better chance of bone healing, however, it will inevitably lead to secondary deformities that may or may not be tolerated. b

3

Type of osteotomy

The type of osteotomy chosen not only depends on the characteristics of the specific osteotomy types as described in chapter “1.1 Posttraumatic deformities and osteotomies” but also on the kind of deformity and its localization as well as the preference and experience of the surgeon, and on the individual demands of the patient.

All osteotomy types have advantages and disadvantages. Some deformities and localizations are ideal for closing-wedge, others for opening-wedge techniques. The closing-wedge osteotomy allows correction at the correct level of the deformity as well as a stable internal fixation.

In difference to acute corrections, in gradual corrections the deformity correction itself is not carried out by the osteotomy but performed later with an external fixator. In gradual corrections a transverse osteotomy of the bone should preferably be performed leaving the periosteum intact as much as possible to enhance callotasis.

4

Bone healing

The healing process of long bones occurs according to one of the following principles: First, anatomical reduction and rigid (ie, absolutely stable) fixation leads to primary bone healing with direct ingrowth of Haversian systems across the fracture line without any macroscopically visible callus formation.

Second, elastic (ie, relatively stable) bone fixation, allowing micromotion between the bone fragments shows a completely different healing pattern: abundant callus formation will bridge

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General considerations on indications, types of osteotomy, bone healing, and methods of fixation

the fracture gaps as long as the local vascularity is not disturbed. This type of bone healing is found in correction osteotomies fixed with intramedullary nails. However, elastic plate fixation is not recommended in osteotomy fixations.

Treating malunions by corrective osteotomies may be considered as a form of optimally controlled fracture treatment.

Therefore, depending on the fixation method chosen, different bone healing types are also found during consolidation of osteotomized bone.

Disturbed healing of fractures and osteotomized bone in the metaphyseal area is rare because cancellous bone has a high healing capacity. Therefore, primary cancellous bone healing of a closing-wedge metaphyseal osteotomy stabilized by a compression plate is almost guaranteed. The same is valid in opening-wedge osteotomies if the gap is filled with autologous bone grafts creating intrinsic stability. Healing of openingwedge metaphyseal osteotomized bones without grafts or bone substitutes is possible as long as the fixation guarantees optimal stability. The hematoma in the gap, surrounded by highly active cancellous bone will be organized and will form a fibrin scaffold over which mesenchymal cells will migrate.

The mesenchymal cells invade the hematoma and replace it with callus. Initially much of the callus consists of fibrous tissue. Any movement in the affected area will delay bone formation and bone healing by destroying the newly formed callus and capillaries. In a stable situation, ossification of the callus will occur. Full ossification and callus remodeling are the end stages of this type of bone healing. Stable fixation of an opening-wedge osteotomy should not be mistaken for rigidity achieved by an anatomical reduction and compression plate fixation of an osteotomized diaphysis.

Bone healing after internal fixation of diaphyseal osteotomized bone at the original fracture site follows other principles than primary fracture treatment. The bone is often sclerotic, the periosteum missing and the intramedullary cavity not restored.

All these changes diminish the local vascularitiy and thus the healing capacity. Any elastic bridging plate fixation—as used successfully in the treatment of comminutive fractures—will

fail because sclerotic osteotomized bone fragments will not produce the necessary bridging callus under micromotion. For diaphyseal osteotomies rigid plate fixation including the use of lag screws thus is the gold standard. It must be realized, however, that gap healing exceeding 1 mm cannot be expected in a rigid type of internal fixation, a full compression of the osteotomized bone is necessary. At present, unreamed and reamed nailing is the gold standard in the treatment of long bone fractures. Unreamed nailing of an osteotomized bone, allowing micromotion, will not produce sufficient callus at the osteotomy site of a sclerotic posttraumatic bone. Reaming and stability on a long trajectory is necessary in order to avoid too much micromotion, and minimizing the gap is essential for successful healing.

5

5.1

Autogenous bone grafting in osteotomies for posttraumatic malunions Physiology

Autogenous cancellous or corticocancellous bone grafting is the gold standard for both biological and mechanical purposes. It combines three properties that all contribute to the enhancement of bone healing: osteogenic—a source of vital cells—, osteoinductive—for recruitment of local mesenchymal cells that differentiate into osteoblast-like cells—, and osteoconductive—a scaffold for creeping substitution with ingrowth of new bone and remodeling by functional adaptation.

The osteoblast phase encompasses the direct effect of surviving bone cells that show massive proliferation from the third to fourth postoperative day and, in interaction with osteoblasts, complete breakdown and remodeling of the graft. In addition, there is the indirect effect of osteogenic induction by a variety of bone morphogenic proteins and polysaccharides that are localized in the intercellular matrix. The proper incorporation of a bone graft requires three crucial prerequisites: mechanical stability, good vascularization of the graft bed, and close contact between graft and environment.

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5.2

Principles part

Cancellous and corticocancellous bone grafts

Autogenous cancellous bone grafts did not become popular until modern osteosynthesis techniques were developed.

These techniques enabled adequate fixation and mechanical stabilization of and around the bone graft—important prerequisites for its undisturbed incorporation. In mechanical and anatomical terms, cancellous bone is nothing but “loosely packed bone”. Its honeycomb structure facilitates the nutrition, revascularization, resorption, and remodeling of the graft.

a

b

d

e

Massive corticocancellous grafts, which can be obtained from the pelvis, combine the good properties of cancellous bone with the mechanical firmness afforded by the (relatively thin) cortical layers. These types of grafts are used to provide mechanical strength at the insertion site in order to create new bone formation, eg, in acetabular shelf plasties. In osteotomies these grafts are often used to provide for extra stability of fixation or even act as a complete replacement of fixation material (Fig 1.2-8).

Fig 1.2-8a–f Opening-wedge lateral high tibial osteotomy: fluoroscopic control of osteotomy cut along guide wire (a), measurement of length of opening-wedge gap (b), corticocancellous bone grafts of sufficient length and size taken from the iliac crest (c–d), and inserted in the gap (e), providing sufficient initial stability for functional rehabilitation without fi xation (f).

c

f

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5.3

General considerations on indications, types of osteotomy, bone healing, and methods of fixation

Donor site

The pelvis is the most suitable donor site for autogenous bone grafts. Large amounts of graft material can be removed from the anterior and even more from the posterior iliac crests with low morbidity and without reducing the mechanical properties

a

d

b

e

f

of the pelvis. Other sources are the greater trochanter and to a lesser extent the head of the tibia, the olecranon and the distal radius, femur and tibia (Fig 1.2-9). Removal of larger amounts of cancellous bone from the trochanteric complex entails some risk of fracture as a result of local skeletal weakening.

c

Fig 1.2-9a–f Natural donor sites for autogenous bone–graft harvesting. a Anterior iliac crest. b Posterior iliac crest. c Proximal tibia. d Distal tibia. e Epicondylus lateralis. f Distal radius.

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Principles part

Much has been written about donor-site problems, which we have not seen in hundreds of cases in more than 30 years practice having followed strict principles while harvesting the grafts (Fig 1.2-10). Described donor-site problems are chronic pain, caused by an irregularity of the iliac crest, damage or entrapment of the sensory nerves (ilioinguinalis, cutaneus femoris lateralis), hematoma, infection, and finally pure cosmetic aspects.

Complaint can be expected whenever the anatomical configuration of the anterior iliac crest is permanently changed, eg, by the harvesting of large three-cortical grafts (Fig 1.2-11).

These types of grafts are believed to provide superior stability; however, the same mechanical stability can be achieved using several two-cortical grafts taken only from the inside of the iliac crest. As in any orthopedic procedure, preservation of the visible anatomy is an important factor in order to avoid donor-site problems and to keep the patient happy with the achieved result. The technique described below allows for grafting of corticocancellous grafts and safe reinsertion of the tendons of the abdominal muscles (Fig 1.2-12).

c

a

b

Fig 1.2-10a–d Harvesting bone grafts. a Autogenous bone graft from the anterior iliac crest. b Autogenous bone graft from the posterior iliac crest.

d c d

Corticocancellous bone chips from the anterior iliac crest.

Pure cancellous bone from the anterior iliac crest.

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General considerations on indications, types of osteotomy, bone healing, and methods of fixation

9 cm

6 cm

a

b

c

d

Fig 1.2-11 Completely destroyed iliac crest after removal of threecortical grafts led to clinical and cosmetic complains.

Fig 1.2-12a–d A bicorticocancellous bone graft and additional cancellous bone harvested without changing the external shape of the iliac crest. Reinsertion of the muscles leads to a good cosmetic result.

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5.4

Principles part

Osteotomies and autogenous bone grafts

In the metaphyseal area of bones closing-wedge correction osteotomies will not need bone grafting. Providing the structure of the bone is normal and fully vascularized, the osteotomized bone heals by direct compression of the local cancellous bone.

In opening-wedge osteotomies gaps that are not too large will be bridged by newly formed cancellous bone as long as the internal fixation is stable (see Table 1.2-1).

Diaphyseal malunions, however, may be sclerotic, the intramedullary canal often not remodeled, and the vascularity of the bone decreased. Under these conditions, bone-healing problems are frequent, remaining gaps after full compression of the osteotomized bone will not be bridged, implants inserted for fixation will fail and a consecutive nonunion may be the result. Therefore, for this type of malunion we prefer a surgical approach, which is similar to that of the treatment of an atrophic type non-union: the sclerotic bone is slightly decorticated, small bone pieces are chiseled away from the exterior aspect of the cortex, while preserving their vascular supply, thus creating a well vascularized transplant bed for a cancellous bone graft (see introduction 2.14.1 Tibia shaft, Fig 2.14.1-2e).

The bone graft improves the local vascularization and will strongly enhance osteogenesis. As a result the sclerotic bone at the osteotomy site will be bridged by the formation of a well vascularized callus. This type of pure cancellous bone graft can be taken out of the anterior iliac crest or out of the metaphyseal area of the same bone (see Fig 1.2-10) and even bone debris after reamed intramedullary nailing.

The technique for iliac-crest cancellous bone and corticocancellous bone-graft harvesting is as follows: The anterior iliac crest is approached by a curved medial skin incision and the periosteum is dissected sharply. Using a curved periosteal elevator, a musculo-tendinous flap of the iliac- and abdominal muscles can be created.

By this technique the inside of the pelvis can be approached in a rather atraumatic way. Gauzes are inserted to stop possible bleeding and one or two broad pointed Hohmann retractors are inserted to allow free access to the inside of the pelvis, if necessary down to the sacroiliac joint.

No exposure of the sensatory nerves is necessary. The cutaneus femoris lateralis and ilioinguinalis nerves are well protected in the musculo-tendinous flap. This approach allows for harvesting of the types of grafts needed for reconstructive surgery: elevation of the internal lamina of the pelvis with chisels gives free access to the pure cancellous bone. A large corticocancellous piece of bone can be resected without disturbing the external shape of the pelvis (see Fig 1.2-13). Finally, bicortical wedged grafts can be taken by resection of the inside of the iliac crest leaving the outside intact (Fig 1.2-13) (see case 2.8.5 Intertrochanteric osteotomy for posttraumatic avascular necrosis of the femoral head after a femoral neck fracture).

Transosseus reinsertion of the musculo-tendinous flap with resorbable sutures will restore the shape of the iliac crest and the function of the abdominal muscles (see Fig 1.2-12).

5.5

The main indications to use corticocancellous bone grafts are opening-wedge osteotomies, intraarticular reconstructions, and acetabular shelf plasties. Corticocancellous bone grafts have a mechanical and a biological function. They create intrinsic stability in the osteotomized bone and enhance rapid healing of the created gaps. In contrast, pure, impacted cancellous bone grafts can only be used if the stability of the internal fixation is assured during the ingrowth process of the graft. These types of grafts have no primary mechanical function.

Alternative graft materials

Allogenic bone grafts do have some osteogenic value. The fate of the grafted bone, however, is partly determined by mild immunological defense reactions. Although all cells are destroyed, the intercellular matrix with osteogenic properties endures. During the first avascular period the graft is extremely vulnerable to infection, which may result in the complete loss of all transplanted allogenic bone. In a noninfected, well vascularized environment—especially in younger patients, results are good. We see no indication for heterogenous bone

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General considerations on indications, types of osteotomy, bone healing, and methods of fixation

grafts. The preliminary clinical experience with different artificial bone substitutes—with or without the recently discovered bone morphogenic substances—are promising, nevertheless, autogenous bone grafting still remains the gold standard.

a

c

b

Fig 1.2-13a–c Technique of iliac bone-graft harvesting and creation of a shelf plasty.

6

Fixation methods

Surgeons performing osteotomies should include the choice of a proper fixation technique in their surgical plan of the deformity correction. Implant selection depends on several factors such as patient age, surgical plan regarding correction procedure, type, level and number of osteotomies, as well as on factors determined by the joint, bone and soft tissue. In addition, socioeconomic factors and experience of the surgeon with specific fixation methods may also play an important role in choosing a specific fixation method. It should be noted, however, that making a surgical plan by first selecting a specific fixation method, the type and level of the osteotomies may be restricted and thus cause secondary deformities.

In order to choose the optimal implant for osteotomy fixation a thorough knowledge of the biomechanical properties (principle of fixation and fixation stability), and the type of bone healing (direct or indirect) resulting from application of specific fixation methods is mandatory. Most of this knowledge has been gained through research in fracture fixation and bone healing. In Table 1.2-1 the properties of the different fixation methods are summarized, for further background information we refer to the textbooks available and the cases presented in this book.

Some specific remarks can be made concerning methods used for fixation of the osteotomized bone. In acute corrections, historically a rather rigid fixation method with stability increased by compression was chosen to allow for a functional rehabilitation with early partial or full weight bearing. Plates, especially the angled blade plates are ideal for axial compression of closing-wedge metaphyseal osteotomies, however, at the cost of an often wide surgical exposure. This compression method of fixation can also be reached with the new generation of angle stable plates while using minimally invasive techniques for surgical exposure.

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Principles part

Concepts of bone fi xation Mechanical stability

High = absolute stability

Low = relative stability

Compression Static1 Technique and implants

Dynamic 2

External splinting5 (external fi xator)

External splinting, conservative fracture treatment (cast, traction)

Lag screw and protection plate (DCP, LC-DCP, LCP)

Tension band plate (DCP, LC-DCP, LCP)

Intramedullary splinting5 (intramedullary nail)

Intramedullary splinting (elastic nail) (K-wire)

Direct

Bone healing

Primary

3 4 5

Unlocked4

Tension band

Reduction

2

Locked3

Lag screw (conventional screw)

Compression plate (DCP, LC-DCP, LCP)

1

Splinting

Internal extramedullary splinting Buttress plate (DCP, LC-DCP, LCP)

Bridging with conventional plate (DCP, LC-DCP, LCP and conventional screws)

Wave plate (LC-DCP)

Bridging with locked internal fi xator (LISS, LCP, LHS) Indirect Secondary

Osteotomy under compression—implant under tension.

Compression under function.

Locked splinting with control of length, alignment, and rotation.

Splinting with limited control of length, alignment, and rotation.

Can be changed to dynamic compression in case of a dynamically locked nail or dynamic external fi xator.

Tab 1.2-1

Different concepts of bone fi xation (adapted from [1]).

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General considerations on indications, types of osteotomy, bone healing, and methods of fixation

A splinting method of fixation is also often used for fixation of the osteotomized bone and may be performed with an intramedullary nail, external fixator or by internal extramedullary splinting using conventional bridging plates or internal fixator plates. Stabilization of osteotomized bone with an intramedullary nail is most often restricted to the shaft although latest generation intramedullary nails provide better stability in metaphyseal areas through distal multidirectional screw positioning. For fixation of the osteotomized bone reamed nailing is preferred over unreamed nailing to obtain a long nail-bone contact, increasing stability.

For deformities with coexistent length discrepancy, beside the fixation methods used in acute corrections for gradual lengthening an external fixation device and, more recently, intramedullary lengthening nails are available to the armament of the corrective surgeon. Beside classic Ilizarov ring fixators and monolateral external fixators so-called hybrid fixators combining the advantages of both methods can be used for fixation in gradual angular corrections.

Removal of implants in malunited fractures may cause specific problems. As implants must be exposed and removed before correction, it is usually both logical and safe to stabilize the corrected, osteotomized bone with the same type of implant.

However, in other cases there may be good reasons, eg, disturbed bone- or tissue-healing conditions or expected lack of patient compliance with rehabilitation prescriptions, to switch to another fixation method (Fig 1.2-14).

Implants inserted for fi xation of osteotomized bones should only be removed when solid bone healing is found in radiological follow-up. Especially in gradual corrections with lengthening one must be sure that bone remodeling is complete because of the high risk of fractures or bending in the lengthened bone area. In these cases a secondary bridging plate inserted percutaneously shortens the treatment time.

Socioeconomic factors and high infection risks with internal or external fi xation devices may be decisive reasons to choose one of these methods for fi xation of the osteotomized bone.

Although providing the least amount of stability, external splinting by cast treatment, with or without crossed K-wire fi xation, and intramedullary splinting with elastic nails may be chosen for fi xation of osteotomized bones.

In specific opening-wedge osteotomies performed in the metaphyseal area between the insertions of stabilizing ligaments or tendons of joints there is no need to insert fixation material. The intrinsic stability of the osteotomized bone can be reached by inserting a wedge in the incomplete opening-wedge osteotomy. In these cases the ligaments regaining tension and the tendons crossing the osteotomized bone provide enough dynamic compression through a tension band effect that enables functional postoperative treatment in cooperative patients.

a

b

Fig 1.2-14a–b Malunion after plate fi xation of tibial fracture in a patient noncompliant to partial weight bearing. Closing-wedge correction and reamed intramedullary fi xation provide for immediate full weight bearing.

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7

Principles part

Bibiliography

[1] Rüedi TP, Buckley RE, Moran CG (2007) AO Principles of Fracture Management. 2nd expanded ed.

Stuttgart: Georg Thieme Verlag.

8

Suggestions for further reading

Hierholzer G, Müller KH (1985) Corrective Osteotomies of the Lower Extremity after Trauma. Berlin Heidelberg New York: Springer-Verlag.

Marti RK, Kerkhoffs GM, Rademakers MV (2007) Correction of lateral tibial plateau depression and valgus malunion of the proximal tibia. Oper Orthop Traumatol;19(1):101–113.

Marti RK, ten Holder EJ, Kloen P (2001) Lengthening osteotomy at the intertrochanteric level with simultaneous correction of angular deformities. Int Orthop; 25(6):355–359.

Marti RK, van der Werken C (1982) Alternative indications for external fi xation according to Wagner. Neth J Surg; 34(3):109–116.

Marti RK, Verhagen RA, Kerkhoffs GM, et al (2001) Proximal tibial varus osteotomy. Indications, technique, and five to twenty-one-year results. J Bone Joint Surg Am; 83(2):164–170.

Müller ME (1971) [Osteotomies of the proximal femur.

Taking into acount the shape, function, and load of the hip joint.]

2nd ed. Stuttgart: Georg Thieme Verlag. German.

Paley D (2002) Principles of Deformity Correction.

Berlin Heidelberg New York: Springer-Verlag.

Pfeil J, Grill F, Graf R (1996) [Limb lengthening, deformity correction, treatment of nonunions.]

Berlin Heidelberg New York: Springer-Verlag. German.

Rozbruch SR, Ilizarov S (2007) Limb Lenghtening and Reconstruction Surgery. New York: Informa Healthcare USA, Inc. Strecker W, Keppler P, Kinzl L (1997) [Posttraumatic leg deformities. Analysis and correction.]

Berlin Heidelberg New York: Springer-Verlag. German. van der Werken C, Marti RK (1982) Bone transplantations.

Injury; 13(4):271–278.

Jaarsma RL, Pakvis DF, Verdonschot N, et al (2004) Rotational malalignment after intramedullary nailing of femoral fractures. J Orthop Trauma; 18(7):403–409.

Wagner H (1978) Operative Lengthening of the Femur.

Clin Orthop Relat Res; (136):125–142.

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