Skeletal Radiol (1992) 21:19-21
Skeletal Radiology
Magnetic resonance imaging of nontraumatic shoulder instability in children F. Gudinchet 1, L. Naggar 2, J.M. Ginalski 1, M. Dutoit 2 and P. Sehnyder 1 Departments of 1Radiology and 2Orthopaedics, CHUV Lausanne, Switzerland
Abstract. N o n t r a u m a t i c shoulder instability is infrequent in children. We examined prospectively with high-field magnetic resonance imaging ( M R I ) 11 patients with this disorder, including 2 with H o l t - O r a m syndrome and 11 healthy control subjects. The M R findings in the glenohumeral joint in normally growing children are presented. Two patients with shoulder instability were considered as normal, one presented with type 2 (Zlatkin) labral lesions, three, type 3 and one, type 4 lesions. Close attention to the normal imaging patterns of the maturing glenohumeral joint is required to avoid pitfalls in the interpretation of the images. Key words: Shoulder instability - Child - Magnetic resonance imaging ( M R I )
Two patients suffered from the Holt-Oram syndrome and one from brachial plexus injury secondary to birth trauma. All patients had a history of recurrent anterior, posterior, or multidirectional (one patient) instability unrelated to a traumatic event. A control group of 11 healthy children (6 girls, 5 boys, ranging in age from 1 to 15 years, average 7 years) was also prospectively studied. Imaging was performed with a Siemens 1.5-T Magnetom MR imager with dual surface coil in a Helmholtz configuration. Tl-weighted spin echo (TR 500 600/TE 15) and gradient echo (FL2D 70, TR 500/TE 18) T2*-weighted sequences were used to obtain 3-4 mm thick slices with a minimal interslice gap. Images were obtained in the axial oblique and coronal oblique planes and were prospectively evaluated for the development of hyaline and fibrous cartilage, development of the anterior and posterior labra, capsular insertion in the bone, and bone marrow signal or signal modification. All patients were treated conservatively.
Results Shoulder instability in children m a y be classified as congenital, posttraumatic, involuntary, and voluntary. Congenital dislocation is extremely rare and m a y be secondary to abnormal prenatal development of the shoulder. Glenohumeral joint instability secondary to minor or m a j o r trauma is rare in the skeletally immature patient but becomes more c o m m o n in teenagers who increase their sporting activities [5]. Nontraumatic, voluntary or involuntary shoulder instability is a less well-known entity in children and teenagers, and the normal appearance of the maturing glenohumeral joint has not been reported yet in spite of extensive embryological studies [2]. The aim of this paper is to evaluate nontraumatic shoulder instability in children using magnetic resonance imaging ( M R I ) in comparison with the M R features of the normally growing glenohumeral joint.
Patients and method Seven patients referred for evaluation of recurrent shoulder instability were prospectively studied by MRI at L5 T. There were 3 girls and 4 boys (average age 11 years 6 months, range 7 15 years). Address reprint requests to." Dr. Frangois Gudinchet, Service de
Radiodiagnostic BH 07, CHUV, CH-1011 Lausanne, Switzerland
In healthy children, the anterior and posterior labra on the axial images are normally low signal, triangular structures on all sequences, with the apex pointing away from the glenoid, to which the capsule is usually attached (Fig. 1). Hyaline articular cartilage covers the bony glenoid and can also be found between the bone and fibrous labrum at the labral base. In teenagers as in adults [3], a second area of high signal intensity is observed coursing obliquely through the labrum near the base of its attachment to the glenoid (Fig. 2). This pattern was seen from 8 years on in healthy subjects. None of our patients suffered f r o m seizures or any collagen disease inducing pathologic articular laxity. Two patients with H o l t - O r a m syndrome had rotated scapulae without hypoplasia of the humerus or cardiac abnormalities. There was no history of trauma prior to dislocation. In 4 patients, the capsular insertion assessed at the midglenoid level was type 1 according to K u m m e l and type 2 in 3 patients [6]. Labral lesions occurred anteriorly in 8 shoulders (Figs. 3, 4) and posteriorly in 3 shoulders. Combined lesions were seen bilaterally in a patient with multidirectional instability and in a case of brachial plexus injury since birth (Figs. 5, 6). Labral lesions appeared as linear structures of increased signal intensity in the 9 1992 International Skeletal Society
20
F. G u d i n e h e t et al. : M R I o f n o n t r a u m a t i c s h o u l d e r instability
Fig. 1. Normal glenoid labrum in a 1-year-old boy. Axial image, gradient echo (TR 500/TE 18, flip angle 70~ On the gradient echo sequence, flbrocartilage such as the anterior (arrow) and posterior (curved arrow) labrum appears dark, contrasting with a high signal hyaline cartilage (small arrow) Fig. 2. Normal anterior labrum in a 15-year-old girl. Axial gradient echo image shows a high signal linear structure (arrow) coursing through the anterior labrum Fig. 3. Recurrent anterior dislocation in a 6-year-old girl. Tl-weighted axial image (TR 500/TE 15). Absence of the normal triangular shape of the anterior labrum. A portion of the torn labrum or capsule (arrow) is shown just anterior to the expected location of the labrum Fig. 4. Recurrent anterior dislocation in a 12-year-old boy with Holt-Oram syndrome; axial gradient echo image (TR 500 TE 18, flip angle 70~ Anterior labral tear (arrow) is seen as a linear band extending to both surfaces of the labrum Fig. 5. Multidirectional instability in a 14-year-old boy, axial image of right side. The patient was asked to dislocate his shoulder during the sequence. Gradient echo (TR 500 TE 18, flip angle 70~ A torn posterior labrum is present (arrow). The surface of the glenoid is grossly retroverted following multiple posterior dislocations, contributing to the instability. The capsule also appears detached from the labrum posteriorly. Absence of the normal triangular shape of the anterior labrum (arrowhead) Fig. 6. Posterior dislocation and glenoid malformation in a 10-year-old girl with brachial plexus palsy secondary to birth trauma. Axial gradient echo image (TR 500 TE 18, flip angle 70~ A flattened posterior part of the glenoid and blunt posterior labrum (arrow) are present
labrum extending to its surface (Figs. 3, 4) or as changes in morphology including blunting and fragmentation (Figs. 5, 6). The shoulders of two patients were considered to be normal. One patient had type 2 and 3 patients had type 3 labral lesions according to Zlatkin [11]. One patient with multidirectional instability had a type 4 labral lesion. None of our patients showed signs of associated supraspinatus tendinitis or tear, and there were no Hill Sachs or Bankart lesions. Deformities of the glenoid fossa and humeral head were present in one patient with a brachial plexus injury. Discussion
Disability due to recurrent subluxation of the humerus is a common problem in adults, and the identification of labral tears has become an important diagnostic goal.
The normal appearance of the growing glenohumeral joint and the glenohumeral injuries of growing children, however, have not been described frequently. The capsular mechanism described by Townley [9] is the primary stabilizer of the shoulder and is divided into two parts. The anterior part is composed of the synovial membrane, capsule, glenoid labrum, subscapularis muscle and tendon, and scapular periosteum. The posterior capsular mechanism consists of the posterior capsule, synovial membrane, posterior labrum with periosteal attachments, and rotator cuff muscles. Any defect in the capsular mechanism may result in recurrent shoulder instability, which may be classified as congenital, posttraumatic, involuntary, and voluntary. Trauma is the most frequent cause of glenohumeral instability, and the MR features of anatomic and functional instabilities have been described by Kleinman [5]. These lesions generally affect athletic teenagers and
F. Gudinchet et al. : MRI of nontraumatic shoulder instability young adults and may result in fracture of the anteroinferior margin of the bony glenoid or tears of the anterior and posterior labra. Our patients' age ranged from 7 to 15 years, and they were not involved in sport-related activities. Extensive anatomic and embryological studies have been performed to find congenital abnormalities responsible for recurrent dislocation o f the shoulder and have described the maturation of the labrum and capsule [2]. U h t h o f f and Piscopo have reported a capsular insertion into the neck of the scapula creating a pouch in 23% of 52 specimens studied and speculated that a redundant anterior capsule could be a developmental variant [10]. Two of our patients showed an anterior capsular insertion more medially situated along the scapular neck consistent with a type 2 insertion [6]. Posterior dislocations of the glenohumeral joint are rare and are associated with trauma, athletical overuse, and electric shock or seizures. In patients with multidirectional instability, the cause is often an abnormality of the soft-tissue elements, and a redundant capsule may be observed [3]. Holt-Oram syndrome is an autosomal dominant entity associating skeletal defects with congenital cardiovascular disorders; patients with skeletal defects alone may be seen. This syndrome may lead to hypoplasia or absence of the humerus, deformation of the humeral head, small and rotated scapulae, hypoplastic glenoid fossa, Sprengel's deformity, and accessory bones [8]. In our series, two patients presented with Holt-Oram syndrome and rotated scapulae and suffered from recurrent, bilateral, anterior shoulder instability. Many of the lesions described in shoulder instability can be clearly identified on M R I which is tending to replace the use of arthrography and arthroscan [3, 5, 7, 11]. These include bone lesions as well as soft-tissue lesions involving the capsule and labrum. The most common bone abnormalities are Hill Sachs lesions o f the humeral head and fractures of the inferior glenoid margin. Those lesions were not present in our series. The soft-tissue lesions associated with anterior instability are lesions of the labrum, anterior capsule, or both. Cartilaginous lesions consist in avulsions or tears of the glenoid labrum. Zlatkin has classified abnormal labral appearance into four types and shown for adult patients that MRI had a sensitivity of 88% and a specificity of 93% in evaluating the presence of a labral tear [11]. Recently, M R arthrography using gadopentate was found to ira-
21 prove the accuracy of M R I in the evaluation o f glenoid tears and rotator cuff lesions in 23 patients [4]. The lesions encountered in our series were type 3 labrum in 3 patients and type 4 labrmn in 1 patient with multidirectional instability. However, I patient with voluntary anterior instability showed no sign of labral lesions. In healthy children, the signal intensity of the labra was found to change with increasing age. The hyaline cartilage covering the bony glenoid could always be seen at the labral base, but a second area of linear high signal intensity was observed coursing through the labrum as in adults in children above 8 years of age. We speculated that this pattern could be due to the normal anterior capsular recess mentioned by Crues [1]. M R I is the procedure of choice to diagnose in a noninvasive way bone, glenoid labrum, and capsular abnormalities in children with nontraumatic shoulder instability. Close attention to the normal imaging patterns of the maturing glenohumeral joint is required for high diagnostic accuracy. References
1. Crues JV III (1991) Magnetic resonance of shoulder injuries. The 90th annual meeting ARRS, Boston, May 1991, p 321 2. Gardner E, Gray DJ (1953) Prenatal development of the human shoulder and acromioclavicular joints. Am J Anat 219 3. Helms CA, Holt RG (1989) MRI of the shoulder. Perspect Radiol 2 (2) : 1 4. Iannotti JP, Zlatkin MB, Esterhai JL, Kressel HY, Dalinka MK, Spindler KP (1991) Magnetic resonance imaging of the shoulder. J Bone Joint Surg [Am] 73 (1):/7 5. Kleinman PK, Spevak MR (1990) Advanced pediatric joint imaging. In: JJ Kaye (ed) Imaging of joints. Radiol Clin North Am 1100-1109 6. Kummel BM (1979) Spectrum of lesions of the anterior capsular mechanism of the shoulder. Am J Sports Med 7:111 7. Meyer SJF, Dalinka MK (1990) Magnetic resonance imaging of the shoulder. Semin ultrasound, CT, MR 11 (4) : 253 8. Taybi H, Lachman RS (1990) Radiology of syndromes, metabolic disorders, and skeletal dysplasias, 3 edn. Year Book Medical, p 222 9. Townley CO (1950) The capsular mechanism in recurrent dislocation of the shoulder. J Bone Joint Surg [Am] 32 : 370 10. Uhthoff HK, Piscopo M (1985) Anterior capsular redundancy of the shoulder: congenital or traumatic? J Bone Joint Surg [Br] 67 (3): 363 11. Zlatkin MB (1990) MR Imaging of the shoulder: current experience and future trends; 76th Annual Meeting of the RSNA, Syllabus, special course, p. 255-267
Skeletal Radiology
Magnetic resonance imaging of nontraumatic shoulder instability in children F. Gudinchet 1, L. Naggar 2, J.M. Ginalski 1, M. Dutoit 2 and P. Sehnyder 1 Departments of 1Radiology and 2Orthopaedics, CHUV Lausanne, Switzerland
Abstract. N o n t r a u m a t i c shoulder instability is infrequent in children. We examined prospectively with high-field magnetic resonance imaging ( M R I ) 11 patients with this disorder, including 2 with H o l t - O r a m syndrome and 11 healthy control subjects. The M R findings in the glenohumeral joint in normally growing children are presented. Two patients with shoulder instability were considered as normal, one presented with type 2 (Zlatkin) labral lesions, three, type 3 and one, type 4 lesions. Close attention to the normal imaging patterns of the maturing glenohumeral joint is required to avoid pitfalls in the interpretation of the images. Key words: Shoulder instability - Child - Magnetic resonance imaging ( M R I )
Two patients suffered from the Holt-Oram syndrome and one from brachial plexus injury secondary to birth trauma. All patients had a history of recurrent anterior, posterior, or multidirectional (one patient) instability unrelated to a traumatic event. A control group of 11 healthy children (6 girls, 5 boys, ranging in age from 1 to 15 years, average 7 years) was also prospectively studied. Imaging was performed with a Siemens 1.5-T Magnetom MR imager with dual surface coil in a Helmholtz configuration. Tl-weighted spin echo (TR 500 600/TE 15) and gradient echo (FL2D 70, TR 500/TE 18) T2*-weighted sequences were used to obtain 3-4 mm thick slices with a minimal interslice gap. Images were obtained in the axial oblique and coronal oblique planes and were prospectively evaluated for the development of hyaline and fibrous cartilage, development of the anterior and posterior labra, capsular insertion in the bone, and bone marrow signal or signal modification. All patients were treated conservatively.
Results Shoulder instability in children m a y be classified as congenital, posttraumatic, involuntary, and voluntary. Congenital dislocation is extremely rare and m a y be secondary to abnormal prenatal development of the shoulder. Glenohumeral joint instability secondary to minor or m a j o r trauma is rare in the skeletally immature patient but becomes more c o m m o n in teenagers who increase their sporting activities [5]. Nontraumatic, voluntary or involuntary shoulder instability is a less well-known entity in children and teenagers, and the normal appearance of the maturing glenohumeral joint has not been reported yet in spite of extensive embryological studies [2]. The aim of this paper is to evaluate nontraumatic shoulder instability in children using magnetic resonance imaging ( M R I ) in comparison with the M R features of the normally growing glenohumeral joint.
Patients and method Seven patients referred for evaluation of recurrent shoulder instability were prospectively studied by MRI at L5 T. There were 3 girls and 4 boys (average age 11 years 6 months, range 7 15 years). Address reprint requests to." Dr. Frangois Gudinchet, Service de
Radiodiagnostic BH 07, CHUV, CH-1011 Lausanne, Switzerland
In healthy children, the anterior and posterior labra on the axial images are normally low signal, triangular structures on all sequences, with the apex pointing away from the glenoid, to which the capsule is usually attached (Fig. 1). Hyaline articular cartilage covers the bony glenoid and can also be found between the bone and fibrous labrum at the labral base. In teenagers as in adults [3], a second area of high signal intensity is observed coursing obliquely through the labrum near the base of its attachment to the glenoid (Fig. 2). This pattern was seen from 8 years on in healthy subjects. None of our patients suffered f r o m seizures or any collagen disease inducing pathologic articular laxity. Two patients with H o l t - O r a m syndrome had rotated scapulae without hypoplasia of the humerus or cardiac abnormalities. There was no history of trauma prior to dislocation. In 4 patients, the capsular insertion assessed at the midglenoid level was type 1 according to K u m m e l and type 2 in 3 patients [6]. Labral lesions occurred anteriorly in 8 shoulders (Figs. 3, 4) and posteriorly in 3 shoulders. Combined lesions were seen bilaterally in a patient with multidirectional instability and in a case of brachial plexus injury since birth (Figs. 5, 6). Labral lesions appeared as linear structures of increased signal intensity in the 9 1992 International Skeletal Society
20
F. G u d i n e h e t et al. : M R I o f n o n t r a u m a t i c s h o u l d e r instability
Fig. 1. Normal glenoid labrum in a 1-year-old boy. Axial image, gradient echo (TR 500/TE 18, flip angle 70~ On the gradient echo sequence, flbrocartilage such as the anterior (arrow) and posterior (curved arrow) labrum appears dark, contrasting with a high signal hyaline cartilage (small arrow) Fig. 2. Normal anterior labrum in a 15-year-old girl. Axial gradient echo image shows a high signal linear structure (arrow) coursing through the anterior labrum Fig. 3. Recurrent anterior dislocation in a 6-year-old girl. Tl-weighted axial image (TR 500/TE 15). Absence of the normal triangular shape of the anterior labrum. A portion of the torn labrum or capsule (arrow) is shown just anterior to the expected location of the labrum Fig. 4. Recurrent anterior dislocation in a 12-year-old boy with Holt-Oram syndrome; axial gradient echo image (TR 500 TE 18, flip angle 70~ Anterior labral tear (arrow) is seen as a linear band extending to both surfaces of the labrum Fig. 5. Multidirectional instability in a 14-year-old boy, axial image of right side. The patient was asked to dislocate his shoulder during the sequence. Gradient echo (TR 500 TE 18, flip angle 70~ A torn posterior labrum is present (arrow). The surface of the glenoid is grossly retroverted following multiple posterior dislocations, contributing to the instability. The capsule also appears detached from the labrum posteriorly. Absence of the normal triangular shape of the anterior labrum (arrowhead) Fig. 6. Posterior dislocation and glenoid malformation in a 10-year-old girl with brachial plexus palsy secondary to birth trauma. Axial gradient echo image (TR 500 TE 18, flip angle 70~ A flattened posterior part of the glenoid and blunt posterior labrum (arrow) are present
labrum extending to its surface (Figs. 3, 4) or as changes in morphology including blunting and fragmentation (Figs. 5, 6). The shoulders of two patients were considered to be normal. One patient had type 2 and 3 patients had type 3 labral lesions according to Zlatkin [11]. One patient with multidirectional instability had a type 4 labral lesion. None of our patients showed signs of associated supraspinatus tendinitis or tear, and there were no Hill Sachs or Bankart lesions. Deformities of the glenoid fossa and humeral head were present in one patient with a brachial plexus injury. Discussion
Disability due to recurrent subluxation of the humerus is a common problem in adults, and the identification of labral tears has become an important diagnostic goal.
The normal appearance of the growing glenohumeral joint and the glenohumeral injuries of growing children, however, have not been described frequently. The capsular mechanism described by Townley [9] is the primary stabilizer of the shoulder and is divided into two parts. The anterior part is composed of the synovial membrane, capsule, glenoid labrum, subscapularis muscle and tendon, and scapular periosteum. The posterior capsular mechanism consists of the posterior capsule, synovial membrane, posterior labrum with periosteal attachments, and rotator cuff muscles. Any defect in the capsular mechanism may result in recurrent shoulder instability, which may be classified as congenital, posttraumatic, involuntary, and voluntary. Trauma is the most frequent cause of glenohumeral instability, and the MR features of anatomic and functional instabilities have been described by Kleinman [5]. These lesions generally affect athletic teenagers and
F. Gudinchet et al. : MRI of nontraumatic shoulder instability young adults and may result in fracture of the anteroinferior margin of the bony glenoid or tears of the anterior and posterior labra. Our patients' age ranged from 7 to 15 years, and they were not involved in sport-related activities. Extensive anatomic and embryological studies have been performed to find congenital abnormalities responsible for recurrent dislocation o f the shoulder and have described the maturation of the labrum and capsule [2]. U h t h o f f and Piscopo have reported a capsular insertion into the neck of the scapula creating a pouch in 23% of 52 specimens studied and speculated that a redundant anterior capsule could be a developmental variant [10]. Two of our patients showed an anterior capsular insertion more medially situated along the scapular neck consistent with a type 2 insertion [6]. Posterior dislocations of the glenohumeral joint are rare and are associated with trauma, athletical overuse, and electric shock or seizures. In patients with multidirectional instability, the cause is often an abnormality of the soft-tissue elements, and a redundant capsule may be observed [3]. Holt-Oram syndrome is an autosomal dominant entity associating skeletal defects with congenital cardiovascular disorders; patients with skeletal defects alone may be seen. This syndrome may lead to hypoplasia or absence of the humerus, deformation of the humeral head, small and rotated scapulae, hypoplastic glenoid fossa, Sprengel's deformity, and accessory bones [8]. In our series, two patients presented with Holt-Oram syndrome and rotated scapulae and suffered from recurrent, bilateral, anterior shoulder instability. Many of the lesions described in shoulder instability can be clearly identified on M R I which is tending to replace the use of arthrography and arthroscan [3, 5, 7, 11]. These include bone lesions as well as soft-tissue lesions involving the capsule and labrum. The most common bone abnormalities are Hill Sachs lesions o f the humeral head and fractures of the inferior glenoid margin. Those lesions were not present in our series. The soft-tissue lesions associated with anterior instability are lesions of the labrum, anterior capsule, or both. Cartilaginous lesions consist in avulsions or tears of the glenoid labrum. Zlatkin has classified abnormal labral appearance into four types and shown for adult patients that MRI had a sensitivity of 88% and a specificity of 93% in evaluating the presence of a labral tear [11]. Recently, M R arthrography using gadopentate was found to ira-
21 prove the accuracy of M R I in the evaluation o f glenoid tears and rotator cuff lesions in 23 patients [4]. The lesions encountered in our series were type 3 labrum in 3 patients and type 4 labrmn in 1 patient with multidirectional instability. However, I patient with voluntary anterior instability showed no sign of labral lesions. In healthy children, the signal intensity of the labra was found to change with increasing age. The hyaline cartilage covering the bony glenoid could always be seen at the labral base, but a second area of linear high signal intensity was observed coursing through the labrum as in adults in children above 8 years of age. We speculated that this pattern could be due to the normal anterior capsular recess mentioned by Crues [1]. M R I is the procedure of choice to diagnose in a noninvasive way bone, glenoid labrum, and capsular abnormalities in children with nontraumatic shoulder instability. Close attention to the normal imaging patterns of the maturing glenohumeral joint is required for high diagnostic accuracy. References
1. Crues JV III (1991) Magnetic resonance of shoulder injuries. The 90th annual meeting ARRS, Boston, May 1991, p 321 2. Gardner E, Gray DJ (1953) Prenatal development of the human shoulder and acromioclavicular joints. Am J Anat 219 3. Helms CA, Holt RG (1989) MRI of the shoulder. Perspect Radiol 2 (2) : 1 4. Iannotti JP, Zlatkin MB, Esterhai JL, Kressel HY, Dalinka MK, Spindler KP (1991) Magnetic resonance imaging of the shoulder. J Bone Joint Surg [Am] 73 (1):/7 5. Kleinman PK, Spevak MR (1990) Advanced pediatric joint imaging. In: JJ Kaye (ed) Imaging of joints. Radiol Clin North Am 1100-1109 6. Kummel BM (1979) Spectrum of lesions of the anterior capsular mechanism of the shoulder. Am J Sports Med 7:111 7. Meyer SJF, Dalinka MK (1990) Magnetic resonance imaging of the shoulder. Semin ultrasound, CT, MR 11 (4) : 253 8. Taybi H, Lachman RS (1990) Radiology of syndromes, metabolic disorders, and skeletal dysplasias, 3 edn. Year Book Medical, p 222 9. Townley CO (1950) The capsular mechanism in recurrent dislocation of the shoulder. J Bone Joint Surg [Am] 32 : 370 10. Uhthoff HK, Piscopo M (1985) Anterior capsular redundancy of the shoulder: congenital or traumatic? J Bone Joint Surg [Br] 67 (3): 363 11. Zlatkin MB (1990) MR Imaging of the shoulder: current experience and future trends; 76th Annual Meeting of the RSNA, Syllabus, special course, p. 255-267
