Congenital pseudarthrosis of the clavicle: a clinical and radiological examination

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Results of the clinical and radiological examination of 20 children aged between 2 years and 13 years with congenital pseudarthrosis of the clavicle are presented. In 35% cases, malformations of the cardiovascular and musculoskeletal systems were identified. The most common variants of the affected clavicle were shortening, localization of nonunion in the distal part of its middle third, and thinning. Less frequent deformations included thickening of the ends of the bone fragments with moderate sclerosis of all bone fragments and normal bone structure of the diaphysis; deformity of bone fragments (in 60% cases) mainly in the frontal plane; and the displacement of bone fragments in the cranial direction. These changes need to be considered when planning surgery.


Congenital pseudarthrosis of the clavicle (CPC) is a rare congenital disorder. Although the incidence of this disease in newborns is currently unknown, the annual incidence among all patients admitted to The Turner Scientific and Research Institute for Children’s Orthopedics is 0.05%-0.1%.

For a long time, CPC was considered as pseudoform cleidocranial dysplasia. In 1910, D. Fitzwilliams was the first to identify CPC as an entity distinct from cleidocranial dysplasia, neurofibromatosis, and birth injury [1].

The etiopathogenesis of CPC has garnered widespread attention of the investigators. One distinctive feature of CPC is the right-side involvement, mainly between the middle- and distal-third of the clavicle. Owen proposed that this could be explained by the higher risk of injury to the right shoulder when a child is being born in a cephalic presentation [2].

Lloyd-Roberts et al. (1975) found unusually elevated 1st or cervical ribs in some patients with CPC and suggested that pressure from the subclavian artery on the developing clavicle might be an etiological factor [3].

Most authors have proposed an abnormal coalescence of the two clavicle ossification centers as the underlying pathophysiology for CPC [2-4]. Thus, none of the currently known theories can completely reveal the underlying cause of CPC. However, the deformity of the clavicle bone fragments; the presence of endosteal, endochondral, and periosteal osteogenesis; cartilage at the ends of the bone fragments; and fibrous tissue in the interfragmental layer provide strong evidence for bone tissue dysplasia as the primary pathophysiology of CPC development [5].

The clinical pattern of CPC was reported by Figueiredo et al. as a deformity of the shoulder girdle; pathological mobility in the middle- or distal-third of the clavicle; occasional bulging of bone fragment ends, contoured under the skin; diastasis, or slit-like space, between the thickened or thinned ends of bone fragments; and deformity of the distal fragment of the clavicle [6].

Currently, there is no detailed description of the deformities of the clavicle bone fragments and no classification reflecting the types and severity of these deformities in children with CPC.

Indications for surgical treatment of CPC are an ongoing topic of debate, and conserving full function of the upper extremities in these patients is considered as a contraindication for surgical treatment [7, 8].

However, according to some authors, severe deformity as well as shortening and cosmetic disability of the shoulder girdle and subluxation and habitual dislocation of the shoulder joint are absolute indications for surgical treatment of CPC [9-11].

Following are the established basic principles of surgical treatment in patients with CPC: correction of the bone fragment deformity, restoration of the physiological axis of clavicle, restoration of clavicle length, replacement of bone tissue defect with active osteoplastic material, and stable osteosynthesis of bone fragments. There are only few reports available describing the presence of clavicle bone fragment deformities in children with CPC, and a better understanding of their role in the planning of surgical intervention is critical [5].

Purpose of study

To define the types of clavicle bone fragment deformities in children with CPC based on clinical and radiographic examination.

Material and methods

In total, 20 children with CPC [10 boys (50%) and 10 girls (50%)] between the age of 2.6 and 13 years (mean, 7.1 years) who were admitted to the department of Bone Diseases at the Turner Scientific and Research Institute for Children’s Orthopedics were included in this study. CPC predominantly affected the right side in 18 patients (90%) and affected the left side in remaining two patients (10%). All patients underwent clinical and radiological examinations.

The clinical study included confirmation of patient complaints provided by either the patient or parents, for younger patients. Visual examination was performed with a focus on the presence of dysplastic signs of development, shoulder girdle and clavicle deformities, function of the shoulder joint, and pathological mobility of the clavicle.

X-ray examination was performed by assessing radiographs of both clavicles in frontal and axial views using digital diagnostic X-ray with Philips Digital Diagnost (Philips) in all patients.

In addition, computed tomography (CT) of the clavicle with three-dimensional (3D) reconstruction using helix CT scanner (Brilliance CT 64; Philips) was performed in 15 patients. In radiographic and CT images, the following parameters were evaluated: extent of the shortening of the clavicle with pseudarthrosis in comparison with the unaffected side, length of the proximal and distal fragments as percentages of the total clavicle length, shape of the bone fragment ends (thick, normal, or thin), bone tissue structure at the ends of bone fragments, extent of diastasis between the ends of bone fragments, and plane and angle of the bone fragment deformity [12].

Results and Discussion

The main complaints in patients with CPC and their parents were the presence of cosmetic defects presenting as deformities in the clavicular region and asymmetry of the shoulder girdle. Only two patients complained of pain in the area of pseudarthrosis because of load-bearing and pressure due to backpack straps applied to the affected area. During examination, clavicle deformity, abnormal mobility at the level of pseudarthrosis, and shortening of the shoulder girdle were noted in all patients. Notably, CPC at birth was diagnosed only in 12 of 20 patients; the age of diagnosis in the remaining 8 patients was between 3 and 11 months. Clinically, mild symptoms of CPC diagnosed at birth or identified during the initial months of life progressed with age; by the age of 4–6 years, CPC was usually clearly visible as a cosmetic defect.

For more objective assessment of the types of clavicle bone fragment deformities, we analyzed only CT images.

Measurement of the clavicle length revealed shortening of the affected clavicle in all cases, which ranged between 6 mm and 9 mm (mean, 6.3 mm or 8% of the total clavicle length) in children with CPC who were under the age of 10 years. The clavicle length in two children aged 12 and 14 years were 15 and 28 mm, respectively, indicating the progression of clavicle shortening with increasing age.

Measurement of the length of the distal and proximal fragments in CPC has led to the establishment of the fact that the proximal fragment is longer than the distal fragment. Thus, the length of the proximal fragment ranged from 51% to 59%, whereas that of distal clavicle fragment ranged from 41% to 49% of the clavicle length. Thus, CPC in all cases was localized in the distal middle part of the clavicle or between the middle- and distal-third.

Further analysis of the shape of the bone fragment ends in patients with CPC showed that thinning was predominant (n = 10), followed by moderate thickening (n = 6); only in four patients, the bone fragment ends were normal.

The extent of diastasis between the bone fragment ends is presented in Table 1.

Our analysis revealed that the extent of diastasis between bone fragment ends ranged from 2 to 15 mm (mean, 8.5 mm ± 0.5 mm) and very rarely exceeded 15 mm. No clear correlation between the extent of diastasis and patient age was observed.

The main outcome of this study was the determination of bone fragment deformity types, which are presented in Table 2.

Thus, only 40% of the patients in this study did not have any deformities of the bone fragments in CPC lesions (Fig. 1), whereas the remaining patients (60%) had numerous distinct deformities (Fig. 2). Specifically, the deformity of the proximal fragment in 3 of 5 cases was localized in the proximal metaphysis of clavicle, whereas it was detected in the middle part of the proximal fragment in 2 cases. In 4 of these 5 cases, the end of the fragments was displaced in the cranial direction, whereas the direction was towards the abdomen only in 1 case. The angle of deformity was measured in the frontal plane and was determined to be between 25° and 45° (± 10°).

The top of the distal fragment deformity was usually localized in the middle part with the fragment end displaced towards the cranial direction. The angle of deformity was between 40° and 60° (± 14.2°).

Analysis of the bone tissue structure showed the presence of moderate sclerosis only at the ends of bone fragments. Clinical evaluation of patients with CPC revealed the presence of concomitant malformations in 7 (35%) out of 20 patients. Spina bifida was detected in 3 patients, whereas thoracic spine scoliosis of 1° was detected in one patient. In two patients, there was hip dysplasia and congenital elevation of the scapula. Two patients had cardiac malformations (aortic coarctation, additional chord of the left ventricle, and patent foramen ovale).

Based on the clinical and radiological examination, patients with CPC were classified into the following groups:

  1. According to the side with pseudarthrosis:
    1. Right
    2. Left
    3. According to the shape of bone fragment ends:
      1. Normal thickness
      2. Thinning
      3. Thickening
      4. According to the type of deformity in bone fragments:
        1. No deformity
        2. Deformity of only the distal fragment in its middle or distal part
        3. Deformity of only the proximal fragment in its middle or metadiaphyseal part
        4. Deformity of the distal and proximal bone fragments in their middle or metadiaphyseal parts
        5. According to the presence of comorbidity:
          1. Isolated
          2. In combination with other malformations:

                                                             i.      congenital malformation of the spine

                                                           ii.      congenital malformation of the heart

                                                        iii.      congenital elevation of the scapula

                                                         iv.      hip dysplasia


The course of CPC in children was complicated by the presence of concomitant malformations of musculoskeletal and cardiovascular system in 35% of the cases, which requires careful clinical examination of patients during preparation for surgery.

The most commonly observed characteristics of CPC in this study were shortening of the clavicle and presence of a pseudarthrosis between its middle and distal thirds. In addition, thinning of bone fragment ends was more commonly observed, whereas thickening was rare. Additional findings included the presence of moderate sclerosis and normal bone structure of diaphysis, deformity of the bone fragments observed in 60% of the cases, predominantly in the frontal plane, and displacement of bone fragment ends in the cranial direction.

The use of CT with 3D reconstruction of the affected clavicle facilitates the identification of main components of the deformity in the affected clavicle and has a significant impact on the planning of surgical intervention in patients with CPC.

Alexander P Pozdeev

MD, PhD, professor, chief research associate, Department of bone pathology. The Turner Scientific and Research Institute for Children’s Orthopedics

Author for correspondence.

Russian Federation д. м. н., профессор, главный научный сотрудник отделения костной патологии ФГБУ «НИДОИ им. Г.И. Турнера» Минздрава России

Julia B Sukharskaya

MD, radiologist, Department of radiology, The Turner Scientific and Research Institute for Children’s Orthopedics


Russian Federation врач-рентгенолог отделения лучевой диагностики ФГБУ «НИДОИ им. Г.И. Турнера» Минздрава России

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Copyright (c) 2016 Pozdeev A.P., Sukharskaya J.B.

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