Leg Length Inequality




(1)
Groningen, The Netherlands

 




One Leg is Shorter or Longer than the Other



One Leg is Shorter than the Other






  • A312070_1_En_15_Figa_HTML.gif Complaint: the parents notice that one of the child’s legs is shorter than the other or they find that the child has an abnormal gait (Fig. 15.1).


  • A312070_1_En_15_Figb_HTML.gif Assessment: on examination leg length difference can be measured with the help of a method using planks.


  • A312070_1_En_15_Figc_HTML.gif Differential diagnosis:



    • congenital



      • idiopathic hemihypotrophy (hemihypoplasia)


      • Russell-Silver syndrome


      • congenital deficiency


      • developmental dysplasia of the hip


      • talipes equinovarus (pes equinovarus, clubfoot)


    • vascular



      • Legg-Calvé-Perthes disease


      • (Perthes disease, coxa plana, Waldenström disease)


      • ischemic necrosis of the femoral head


    • neurological



      • spastic hemiplegia


      • poliomyelitis


      • peripheral nerve or plexus injury


      • plexus injury


    • growth plate damage



      • acute osteomyelitis


      • septic arthritis of the hip


      • growth plate fracture


      • slipped capital femoral epiphysis


      • radiotherapy


    • bone tumor



      • unicameral bone cyst (juvenile-, solitary-, simple bone cyst)


      • osteochondroma (exostosis)


      • enchondroma



        • Ollier disease


        • Mafucci syndrome


  • A312070_1_En_15_Figd_HTML.gif Explanatory note: congenital


A312070_1_En_15_Fig1_HTML.jpg


Fig. 15.1
Measurement of leg length difference using the plank technique. (a) The anterior superior iliac spines are palpated with the thumbs. If the thumbs are not at the same height there is a leg length difference. (b) If there is a leg length difference, then planks with various thicknesses are placed under the foot on the shorter side, until the anterior superior iliac spines are at the same level. The thickness of the planks is the measurement of the shortening. (c) Leg length difference in the thighs can be shown with the child lying on its back with the legs and knees flexed to 90°. If there is a difference in knee height there is a leg length difference in the thighs as in this case (the same patient as in (a). (d) By allowing the patient to lie supine with the knees flexed to 90° one can see if there is a leg length difference in the lower legs. If the soles of the feet are at the same height as in this case, there is only a difference in the length of the upper legs (the same patient as in (a)


Idiopathic hemihypotrophy

Hemihypotrophy isusually idiopathic but can also be part of the Russell-Silver syndrome. 1 Idiopathic hemihypotrophy can involve not only a complete body half but may involve just one extremity. We are dealing with hemihypotrophy if the short leg is thinner and does not fit in with the rest of the body. Hemihypotrophy occurs in 1 in 100,000 individuals. Apart from the difference in leg length other abnormalities may be present such as palate anomalies, cleft lip and palate, urogenital anomalies and mental retardation. The final difference in leg length is generally not more than 2 cm.


Congenital deficiency

In this case the whole lower extremity is missing or parts of it and in the latter case there is usually a severe difference in leg length (Fig. 15.2).

A312070_1_En_15_Fig2_HTML.jpg


Fig. 15.2
Congenital deficiency: in this case a proximal focal femur deficiency on the right side


Developmental dysplasia of the hip

An untreated unilateral hip dislocation will lead finally to a leg length difference of 5–6 cm (Fig. 15.3).

A312070_1_En_15_Fig3_HTML.jpg


Fig. 15.3
Leg length difference of 2 cm in the left thigh as a result of a developmental dysplasia with a dislocated left hip. The leg length difference can increase in adulthood up to 5 or 6 cm


Talipes equinovarus

A talipes equinovarus usually causes a leg length difference of less than 1 cm.


Vascular



Legg-calvé-perthes disease

Perthes disease generally causes a leg length difference of not more than 1 cm.


Ischemic necrosis of the femoral head

This can be a complication of a fracture in the proximal part of the femur. In children the chance of an ischemic necrosis of the femoral head is 75 % after a transepiphyseal fracture, a transcervical and a cervico trochanteric fracture and 15 % after an intertrochanteric fracture. Ischemic necrosis of the femoral head causes damage to the proximal femoral epiphysis causing a growth disorder. The final leg length difference is dependent on the age at which this complication occurred.


Neurological



Spastic hemiplegia

In this case the leg length differences are seldom more than 1.5 cm (Fig. 15.4).

A312070_1_En_15_Fig4_HTML.jpg


Fig. 15.4
Right spastic hemiplegia. There will be a maximal leg length difference of 1.5 cm in the involved leg when the child has stopped growing. The leg length difference will be compensated by plantar flexion in the ankle


Poliomyelitis

Leg length differences caused by poliomyelitis are not often seen in better developed countries.


Peripheral nerve or plexus injury

Hemihypotrophy can occur as a result of a nerve injury or plexus injury.


Growth Plate Damage



Acute osteomyelitis

In some cases an acute osteomyelitis can cause a destruction of the growth plate (see Chap. 18). This can lead to substantial growth inhibition. Sometimes the growth plate partially closes and apart from shortening also causes a progressive deformity (Fig. 15.5).

A312070_1_En_15_Fig5_HTML.jpg


Fig. 15.5
(ab) Situation after a meningococcal sepsis in a newborn child with damage to diverse growth plates in the right knee with serious positional deformities and shortening of the right leg as a result. (c) A right knee arthrodesis was carried out because of a serious progressive deformity of the joint. (d) After the right knee arthrodesis an extensive leg length difference remains, which in the first instance was dealt with a sole elevation. In order to prevent ankle instability a long leg splint was mounted onto the shoe. Later on a leg lengthening procedure was carried out (see Fig. 15.15). Operation performed in the early eighties


Septic arthritis of the hip

A septic arthritis of the hip that has been treated too late can lead to destruction and ischemic necrosis of the femoral head. This can lead to a leg length difference of up to 4 or 5 cm, depending on the age of the patient at the time of the infection.


Growth plate fracture

In 1 % of growth plate fractures damage in the growth plate causes a bony connection between the metaphysis and the epiphysis. A shortening will only occur if this bony connection is located centrally. Apart from shortening a misalignment will occur if the bony connection is asymmetrical. The leg length difference that occurs is dependent on the age of the child and the localization of the fracture. The final leg length difference will be greater the younger the child is. Growth plate closure above or under the knee will lead to a greater leg length difference than growth plate closure in the epiphysis in the proximal part of the femur or in the distal part of the tibia.


Slipped capital femoral epiphysis

A slipped capital femoral epiphysis seldom leads to a leg length difference of 2 cm or more (see Chap. 9).


Radiotherapy

Radiotherapy for the treatment of tumors may lead to damage to the growth plate.


Bone Tumor



Unicameral bone cyst, osteochondroma and enchondroma

Bone tumors can inhibit growth. Examples of growth inhibition are in solitary bone cysts, osteochondromata and enchondromas. Enchondromas may be part of Ollier disease2 (Fig. 15.6) or the Mafucci syndrome2. The difference between Ollier disease and the Mafucci syndrome2 is that in the latter subcutaneous hemangiomas are present.

A312070_1_En_15_Fig6_HTML.jpg


Fig. 15.6
Ollier disease. (a) Positional deformity and shortening of the right leg. (bc) Multiple enchondromas in several metaphyses of the right femur and tibia

For supplementary assessment, primary care treatment, when to refer, secondary care treatment, if one leg is longer than the other, see too long leg, pp. 325 and 331 in this chapter.


One Leg is Longer than the Other




Jun 26, 2017 | Posted by in PEDIATRICS | Comments Off on Leg Length Inequality
Premium Wordpress Themes by UFO Themes