Posttraumatic Lower Limb Deformities in Children



Fig. 30.1
Four-year-old child with femur fracture treated by traction in a Thomas’ splint. (a) Injury film. (b) X-ray in Thomas’s splint. (c) At 2 months fracture united with 40° angulation and 3 cm shortening. The malunion is due to muscle forces that were not effectively managed



Deformities following trauma to the extremities are not uncommon and not always dependent on the level of care provided. While some deformities are inevitable due to high-energy trauma and damage to the growing area of long bones, other deformities occur because of suboptimal management allowing the limb to be positioned abnormally or allowing certain muscles to get tight and create a secondary deformity.

Deformities that are not clinically significant or have the potential for substantial remodeling to an acceptable level can be observed. In general, when the residual axial malalignment of a lower extremity long bone exceeds 10°, correction may be warranted.



Causation and Etiological Factors



Box 30.1. Factors Related to Development of Posttraumatic Deformities





  • Injury related



    • Soft tissue

      Skin and soft-tissue loss

      Tendon and muscle injury

      Nerve injury

      Vascular injury


    • Skeletal

      Type of fracture, fracture geometry, and comminution

      Growth plate injury

      Bone loss

      Intra-articular injury


  • Treatment related



    • Missed diagnosis of a fracture


    • Delayed presentation and management


    • Incorrect treatment choice


    • Suboptimal management


    • Overtreatment


    • Iatrogenic problems


  • Complication related



    • Infection


    • Loss of reduction


    • Compartment syndrome


    • Postoperative stiffness


    • Avascular necrosis


  • Patient-related factors



    • Preexisting skeletal problems like dysplasia, syndromes


    • Neuromuscular problems like cerebral palsy, poliomyelitis, muscular dystrophy


    • Altered bone physiology due to osteogenesis imperfecta, metabolic bone disease


    • Pathological fracture with underlying tumor, osteomyelitis


    • Immunocompromise


    • Malnutrition

A posttraumatic deformity can be a result of initial soft-tissue and skeletal injury, its management, or complications. In order to accurately identify the cause and anticipate the natural progression of the deformity, it is important to ascertain the mechanism of injury, initial soft-tissue and bony injury, specifics of the treatment given—conservative and operative, postoperative care, and complications and course of the deformity thus far.


Box 30.2. Etiological Mechanisms for Posttraumatic Deformities





  • Postural or positional


  • Muscle forces


  • Neural and vascular injury


  • Poor skeletal stabilization


  • Damage to the growing area of bone


  • Infection

Deformities can be caused by one or more of the following etiological factors:

1.

Postural or positional: Lack of immobilization or faulty immobilization may cause a deformity, often related to contracture of the adjacent soft tissues. Examples are an equinus deformity of the foot or a knee flexion deformity because of contracture of the gastro-soleus or the hamstrings, respectively.

 

2.

Muscle forces: Varus deformity of the upper femur following a fracture is a classic example of muscle forces at work. The flexor-adductor predominance over the abductor-extensor forces causes this deformity (e.g., Figs. 30.1 and 30.2).

A316936_1_En_30_Fig2_HTML.jpg


Fig. 30.2
Effect of remodeling and growth: Fracture shaft femur in a 4-year-old child. (a) Injury film. (b) Position in plaster after immediate spica showing shortening and recurvatum. (c) At 6 weeks, uniting with 20 varus and 2.5 cm shortening. (d) At 3 months, united with persistent shortening. (e) After 2 years, correction of deformity with equal limb lengths

 

3.

Neural or vascular injury: Neural injury can create deformity because of imbalance of muscle forces or by muscle paralysis causing a postural deformity. Vascular injury may give rise to infarction of muscle followed by its fibrosis and eventually a contracture. Volkmann’s ischaemic contracture is a typical example of such an etiology.

 

4.

Poor skeletal stabilization, loss of reduction, and loss of fixation can all give rise to posttraumatic deformities. Factors such as poor bone quality, traumatic bone loss, and fracture comminution may contribute to inadequate skeletal stabilization (e.g., see Fig. 30.9).

 

5.

Damage to the growing area of bone: Classic examples of these are partial physeal injuries with growth arrest giving rise to various angular deformities (e.g., see Fig. 30.7). Symmetric physeal damage would give rise to limb shortening. Damage to the growing area may be a consequence of the mode of injury or may occur because of its poor management. Salter–Harris type 6 injury is a perichondrial ring injury presenting with a normal X-ray. This is an example of the mode of injury giving rise to deformity (e.g., see Fig. 30.10).

 

6.

Infection: Open skeletal injuries or iatrogenic issues can be complicated by infection which works by damaging bone and cartilage, causing bone lysis and loss, growth plate damage and its sequelae, as well as joint ankylosis and deformity.

 


Classification


Posttraumatic deformities can be classified into different ways to fully understand the current problems as well as potential issues that may arise in the future. Such classification helps in formulating the management plan for the individual patient.


Box 30.3. Classification of Posttraumatic Deformities in Children



Related to the area of bone affected



  • Diaphyseal


  • Metaphyseal


  • Physeal


  • Epiphyseal


Related to the anatomical effect



  • Angulation


  • Rotation


  • Limb length


  • Nonunion


  • Restriction of movement


  • Muscle weakness


Related to the tissue affected



  • Soft tissue

    Skin, fascia, muscle, capsule, or ligaments




  • Skeletal

    Diaphyseal, growth plate, articular


Related to the progression



  • Progressive: Improving: Partial or complete


  • Progressive: Improving, then progressive


Clinical Manifestations


Fixed deformity of the joint, joint stiffness and ankylosis, shortening, angular and torsional deformities, and axial malalignment are all potential clinical manifestations in a posttraumatic situation. Meticulous clinical assessment may point to the static or progressive nature of the deformity. Presence or absence of infection is to be noted as it is an important consideration in management. Examination for neural injury is important and can be challenging in young children, especially in the presence of fixed contractures.


Investigations


Besides plain X-rays, MRI and CT scans may be useful in some patients.

Plain Xrays are the simplest way of monitoring bony deformity. In addition to standard views one may need X-rays in the plane of the deformity. Full-length standing radiographs and scanograms are useful for monitoring limb length.

MRI can give a lot of information about the growth plate (e.g., see Fig. 30.7f, g) and articular cartilage, periarticular ligamentous injury, osteochondral fractures, and articular alignment.

CT scans help define the fracture geometry, area of growth arrest, and presence of a bony bar. It is also a useful tool to quantify torsional deformities.

Occasionally, specialized scans like the radioisotope scans may be required to detect infection. Hematologic tests including a white cell count, sedimentation rate, and C-reactive protein are helpful in such a situation. A more comprehensive metabolic panel may be required in patients with underlying metabolic bone diseases such as various forms of rickets.


Remodeling of Bony Deformities


Remodeling may impact decision making for correcting any bone deformity. The patient’s functional capacity and the surgeon’s experience should also be factors in determining whether to depend on the remodeling capacity of the specific fracture or to consider performing a more aggressive, invasive technique to achieve a satisfactory result [1].

In the typical long bone, 75 % of the remodeling occurs by reorientation of the physis while appositional remodeling of the diaphysis can only be expected to contribute 25 % to the remodeling process.

Important factors influencing remodeling are as follows:

1.

Age of the patient: The older the child the less is the remodeling potential. In general, remodeling of posttraumatic deformities occurs more effectively in children younger than 10 years.

 

2.

Location of the malunion: Metaphyseal fractures remodel better than diaphyseal fractures. Fractures near the fast-growing physes such as lower femur and upper tibia and lower radius and upper humerus remodel better than their counterparts.

 

3.

The plane of the deformity: Angulation in the plane of the joint axis corrects better. Rotations do not correct for all practical purposes. In some fractures overgrowth phenomenon gives rise to correction of limb shortening.

 

4.

Magnitude of angulation and translation.

 


Box 30.4. Factors Affecting Remodeling of Fractures in Children





  • Age


  • Location


  • Plane of deformity


  • Degree of deformity

Some guidelines on acceptability of fracture reduction and remodeling are given at the end of this chapter (see section Acceptability Criteria for Reduction in Lower Limb Fractures).


Case Study (Fig. 30.2)



Clinical Summary


A 4-year-old child was treated for fracture shaft femur by immediate spica. He had 2-cm shortening and varus deformity 3 months post-fracture. Over a period of 2 years, the deformity corrected and child had equal leg lengths.


Philosophy of Treatment


Fracture healing can stimulate bone growth in certain femoral shaft fractures. The amount of overgrowth varies in different reports from 0.4 to 2.7 cm. Overgrowth in femoral fractures appears to be independent of age, fracture level, and position of the fracture at the time of healing. The effect of growth stimulation may continue for up to 3 years following the fracture.


Case Study (Fig. 30.3)




A316936_1_En_30_Fig3_HTML.jpg


Fig. 30.3
A 6-year-old with malunited type 1 SH fracture. (a) Four months from injury, Feb 2011. (b) MRI showing posterior displacement of the physis. (c, d) X-ray and clinical picture 5 months postinjury. (e) X-rays 10 months postinjury showing remodeling and correction of angulation and translation. (f) Complete remodeling at 1.5 years postinjury in 2012


Clinical Summary


A 6-year-old girl presented 4 months after an open fracture of the tibial tuberosity with patellar tendon tear which was debrided, repaired, and cast. She developed a stiff knee for which the original surgeon did a manipulation under anaesthesia. However, the local swelling and deformity increased. A Salter–Harris type 1 injury was diagnosed at presentation. An MRI revealed a posterior displacement of the distal femoral epiphysis with loculated fluid collection along the posterior border.

Different options of management were considered but it was decided to leave her alone in view of the good possibility of remodeling. For the stiff knee physical therapy with range of motion exercises was started. The sequential X-rays show the excellent remodeling (Table 30.1). She regained nearly full knee movement 2 years after the injury.


Table 30.1
Diaphyseal-epiphyseal angle
























Feb 2011

38°

Mar 2011

42°

May 2011

54°

Aug 2011

70°

Nov 2011

82°

Apr 2012

90°


Philosophy of Management


The distal femoral epiphysis is one of the fastest growing physes with rapid remodeling in children. Undisplaced Salter–Harris type 1 injuries need not be fixed, as long as they are immobilized with restricted weight bearing and closely followed with serial radiographs. The ones with displacement may need a gentle reduction and fixation. We prefer that pins not be introduced from the knee level upwards but rather in a reverse fashion from the metaphysis into the epiphysis as recommended by Wall [2]. It is important not to leave pins sticking out of the skin if placed retrogradely. If placed in this fashion they should be buried under the skin for later removal.


Management


Decision making in posttraumatic deformity situations is based on a number of factors, including:



  • Age of the patient


  • Location of the deformity


  • Morphological status of bone, soft tissue, and cartilage


  • Functional loss and impairment


  • Abnormal mechanical loading with risk of joint degeneration


  • Cosmetic aspect

Table 30.2 presents a general schema of the types of interventions.


Table 30.2
General schema of the types of interventions





















































Type of deformity

Nature of intervention

Joint contractures

Manipulation

Splintage

Serial plasters

Soft-tissue release

External fixation

Osteotomy

Arthrodesis

Muscle imbalance

Splintage

Tendon transfer

Arthrodesis

Angular and rotational bony deformities

Osteotomy

Growth modulation

Physeal bar excision

Shortening

Shoe raise

Limb lengthening

Contralateral epiphysiodesis

Limb shortening

Bone loss and nonunion

Bone grafting

Bone transport


Important Posttraumatic Deformities: Lower Limb


In this section we briefly discuss some unique posttraumatic lower limb deformities in children and demonstrate a variety of treatment strategies. However, as noted earlier, the decision making should be individualized based on patient, surgeon, and environmental factors.


Posttraumatic Chondrolysis of the Hip and Avascular Necrosis


Acetabular injuries may be complicated by chondrolysis of the hip, and this may give rise to a fixed flexion and adduction deformity. Likewise hip dislocations and fractures of the femoral neck may be complicated by avascular necrosis. Avascular necrosis may follow the commonly described patterns in the classifications of Kalamchi and MacEwen [3] or of Bucholz and Ogden [4] and management would follow the lines described for such conditions.

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Sep 26, 2016 | Posted by in PEDIATRICS | Comments Off on Posttraumatic Lower Limb Deformities in Children
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