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Radiographic changes with radial head subluxation in children
Printed in the USA * Copyright 0 1990 Pergamon P!ess plc
The Journal of Emergency Mechcine, Vol. 8, pp. 265-269, 1990
RADIOGRAPHIC CHANGES WITH RADIAL HEAD SUBLUXATION IN CHILDREN Howard S. Snyder, Reprint address:
MD
Department of Emergency Medicine, Albany Medical Center Hospital, Albany, New York Howard S. Snyder, MD, Department of Emergency Medicine, Albany Medical Center Hospital, 47 New Scotland Avenue, Albany, NY 12208
no radiographic abnormality is identified (1-14). However, radiographic evidence of radial head subluxation consisting of displacement of the radiocapitellar line (RCL) has been noted in several case reports (15,16). Because of these reports of abnormal radiographs with RHS, this study was designed to document radiographic findings in a series of pediatric patients with RHS.
0 Abstract - Radial head subluxation (RIB) produces no radiographic abnormalities according to most experts. However, recent anecdotal case reports have identified displacement of the radiocapitellar line (RCL) in pediatric patients with RIG. To verify thll finding, we retrospectively reviewed all patients less than 5 years of age who received elbow and forearm radiographs in our emergency department. From January 1988 through April 1989, we identified 20 cases of RI-IS. Of the 20 radiographs, 5 (25%) were read by the attending radiologist as abnormal due to RCL displacement indicating subluxation of the radiocapitellar articulation. All 5 of these radiographs had RCL displacement greater than 3 mm. The remaining normal radiographs had RCL displacement less than or equal to 3 mm. The presence of RCL displacement without disruption of the radiocapitellar articulation confirms the diagnosis of RIG, but does not appear to change treatment or outcome in this subset of patients. In addition, radiographs may not be mandatory when the diagnosis of RHS ls certain. We suggest obtaining radiographs lf the history (i.e., fall) or physical examination is atypical or if reduction is unsuccessful to rule out more serious injuries such as radial head dislocation or fracture. 0 Keywords - radial elbow
head; subluxation;
METHODS All radiographs of the elbow and forearm in patients 5 years of age or less obtained in our emergency department (ED) from January 1988 through April 1989 were identified using a computerized file search. Patient records and radiographs were reviewed, including the attending radiologist’s interpretation of the film at the time of presentation. RI-IS was considered present if manipulative reduction in the ED produced return of function in a child presenting with refusal to use the upper extremity. If manipulative reduction was unsuccessful in the ED, RHS was still considered present if the history indicated a pulling mechanism and the child regained normal function either spontaneously or by additional reduction attempts during follow-up. Patients with a clear history of traumatic injury (i.e., fall, motor vehicle accident, direct blow) were excluded from the study. Displacement of the RCL was measured by the author as the distance between the center of the capitellum and a line bisecting the radius distal to the radial tuberosity.
nursemaid’s
INTRODUCTION Radial head subluxation (RHS), also referred to as “nursemaid’s elbow,” is a common pediatric orthopedic emergency occurring in children less than 5 years of age. The diagnosis is made from history and physical examination followed by successful reduction resulting in return of function within minutes. The utility of radiographs is questionable, and most references claim that
RESULTS Twenty ED presentations by 17 patients were identified
meeting study criteria for RHS. Three patients presented
RECEIVED: 18 September 1989; FINAL SUBMISSIONRECEIVED: ACCEPTED: 3 January 1990
20 December 1989;
265
0736-4679/90 $3.00 + .OO
266
Howard S. Snyder
Table 1. Description of study group with abnormal radlographs
Patient 1 2 3 4 5
Age (months) 10 10 13 27 12
RCL Displacement (mm) AP Lateral 5 3 4 4 5.5
4 4.5 2 5 0
DISCUSSION
Reading Abnormal Abnormal Abnormal Abnormal Abnormal
twice during the study period with RHS. One patient presented to the ED the following day after initial reduction of a RI-IS once again refusing to use the same arm. A second attempt at reduction was successful in restoring full range of motion and radiographs were normal on both occasions. Two patients presented 4 months and 16 months after their initial visit with RHS of the opposite extremity and normal radiographs on both occasions. Of the 20 sets of AP and lateral radiographs, 5 sets (25%) showed displacement of the RCL and were read by the attending radiologist as consistent with radial head subluxation. Lateral subluxation was best visualized on the AP view whereas posterior subluxation was evident on the lateral view. Two patients spontaneously reduced during positioning for radiographs. In the remainder of cases, partial or total return of function was noted after manipulation using supination and flexion or extension. Seventeen reductions were successful in the ED whereas 3 reductions were performed during the follow-up examination the next day. No patients were excluded from the study because of unsuccessful reduction, and all radiographs were obtained before attempted reduction. All 5 patients with radiographic evidence of RI-IS were successfully reduced in the ED. Thirteen patients had a history of traction injury whereas 7 patients had no obvious mechanism of injury. Table 1 describes the study population with abnormal radiographs in terms of measured RCL displacement. The 20 sets of radiographs included a total of 52 films (25 AP, 27 lateral), as multiple films were often obtained. Displacement of the RCL in either view was greater than 3 mm in those radiographs considered abnormal. All films with 3 mm or less of displacement of the RCL were read as normal. Although postreduction films were not obtained, one patient (#15) who spontaneously reduced during radiographic examination had RCL displacement of 5 mm and 0 mm on successive lateral films.
RHS results from longitudinal traction applied to the extended forearm of a child. This often occurs during walking, swinging, or pulling the child by the wrist to prevent a fall. The child refuses to use the affected arm which is held in pronation with slight flexion or full extension. No swelling or deformity is present. Although some passive range of motion is allowed, supination and full flexion usually elicit pain. Disruption of the attachment of the annular ligament to the periosteum of the radial head allows the ligament to interpose between the radial head and capitellum (6). Supination and flexion or extension of the affected forearm with pressure over the radial head results in a palpable click and return of function within minutes. Radiographs of RHS are normal according to the pediatric and orthopedic literature, including several textbooks of pediatric radiology (1-14) Although widening of the space between the radial head and capitellum has been suggested (17), it does not appear to be a reliable finding (6,11). Other case reports which claim to show radiographic abnormalities with RI-IS are referred to in the literature, but closer inspection fails to reveal conclusive evidence (18). Although most references continue to state that radiographs in children with RI-IS are normal, we were unable to locate any studies which were able to verify this finding. This study indicates a 25% (5 of 20 patients) incidence of abnormal radiographs with RHS. Excluding the 2 patients who spontaneously reduced during radiographic examination, the incidence of abnormal radiographs increases to 28% (5 to 18 patients). Miller and Insall (15) reported a 16-year-old male with radiographic evidence of posterior radial head subluxation following a longitudinal traction injury which was diagnosed one year after the injury. Recently, Frumkin (16) presented 3 case reports of children with RHS and radiographic evidence of posterior and lateral subluxation of the radial head as shown by displacement of the radiocapitellar line (RCL). The RCL is formed by a line bisecting the proximal radius and should pass through the center of the capitellum in every view (2,19). Because of bowing of the proximal radius, this line should not extend proximal to the radial tuberosity. Displacement of the RCL indicates subluxation or dislocation of the radial head or fracture of the capitellum (20). Although positioning was difficult in many of our patients secondary to pain, the RCL should remain intact in every view (see Figure 1). It is unclear what constitutes abnormal displacement of the RCL as it has never been studied in a series of normal radiographs.
267
Radial Head Subluxation
04 Figure 1 (a) and (b). AP and lateral elbow radiographs show normal radlocaplteilar line (Ilne bisecting the proxlmal radial shaft passes through the center of the capltellum) lndlcatlng a normal artlculatlon between the radial head and humerus.
Several reasons exist for the lack of recognition of radiographic abnormalities with RHS. Radiographs are not obtained in every patient. Some authors suggest that radiographs are not necessary if history and physical examination are typical of RI-IS (2,3,14). Forced supination of the elbow by the radiographic technician during the positioning may reduce the subluxation as evidenced by 2 patients in our study. In addition, a subtle disruption of the RCL may not be recognized by the radiologist unless it is actually measured. Gross displacement of the RCL with loss of the radiocapitellar articulation, as in radial head dislocation (RI-ID), is obvious but it is
Flgure 2 (a) and (b). AP and lateral radlographs wlth dlsplacement of radlocapltellar line by 4 mm (AP) and 5 mm (lateral).
unclear what amount of displacement is significant and may be seen with RHS. Displacement of the RCL of greater than 3 mm was present in those films considered abnormal by the radiologists in our study (see Figure 2). It is unclear whether the RCL was actually measured for each radiograph, and we speculate that less than 3 mm of displacement is not detectable without measurement. Traumatic radial head dislocation (RHD) is a rare entity occurring, both in the pediatric and adult popula-
268
Howard S. Snyder
tion (19,21,35). RHD is usually seen with a proximal ulnar fracture (Monteggia fracture), but may occur as an isolated entity. Although usually resulting from a fall on an outstretched hand or a motor vehicle accident, a case report exists of an adult with an isolated RHD with a longitudinal traction, hyperpronation injury after grabbing a fence while falling (33). These injuries may be more difficult to reduce, requiring closed reduction under general anesthesia or open reduction (25,27, 28,30,32). Immobilization in flexion and supination is recommended for 3 weeks to prevent recurrence, (28,30). Unlike RHS, the annular ligament is ruptured in RI-ID allowing total disruption of the radiocapitellar articulation. It is interesting that Stelling and Cote (28) recommend x-ray studies to differentiate RHD from RI-IS, whereas most references fail to mention RI-ID in their discussion of RI-IS. We suggest obtaining radiographs if the mechanism of injury is unclear or atypical (i.e., fall, direct blow), the physical examination is atypical (i.e., palpable effusion, visible deformity, point tenderness, pain without manipulation), or attempted reduction is unsuccessful. Children with upper extremity injuries from a fall or motor vehicle accident do not have RI-IS but may instead have a traumatic RI-ID, Monteggia fracture-dislocation, supracondy1a.r humerus fracture, or radial head fracture. Therefore, in addition to the RCL, the presence of a “fat pad sign” (displaced fat pads from hemarthrosis and intra-articular fracture, usually an occult radial head fracture) or a displaced “anterior humeral line” (line
along anterior border of humerus should pass through middle third of capitellum) should be searched for in these instances. Thirteen patients were excluded from this study due to history of a fall. Their radiographs revealed 9 fractures of the radius, ulna, and humerus. These entities clearly are much more serious injuries than RI-IS and require different treatment. In summary, radiographic evidence of RI-IS as evidenced by RCL displacement was identified in 25% of the patients in our study. We have identified a subset of pediatric patients with RI-IS and abnormal radiographs, consisting of RCL displacement greater than 3 mm in either view. The history, physical examination, and response to manipulation were similar in this subset of patients with successful reduction in each case. The presence of RCL displacement confirms the diagnosis of radial head subluxation and did not affect treatment or outcome in this group of patients. Based on our review of the literature and our clinical experience, we suggest that radiographs be obtained if the history or physical examination is atypical. This may detect fractures of the radius, ulna, and humerus which require different treatment in the emergency department. When radiographs are obtained, our study suggests they should also be evaluated for RCL displacement.
Acknowledgment- The author would like to thank Barbara Norton and Jaimie Miller for assistance in preparation and Edward C. Geehr, MD, for his review of this manuscript.
REFERENCES 1. Caffey JP. Pediatric x-ray diagnosis. Chicago: Year Book; 1985:
2. 3. 4. 5. 6.
7. 8. 9. 10. 11. 12.
743. Rogers LF. Radiology of skeletal trauma. New York: Churchill Livingstone; 1982:48l-5. Swischuk LB. Emergency radiology of the acutely ill or injured child. Baltimore: Williams and Wilkins; 1986:355-9. Magi1 HK, Aitken AP. Pulled elbow. Surg Gynecol Obstet. 1954;98:753-6. Corrigan AB. The pulled elbow. Med J Aust. 1965;2:187-9. Salter RB, Zaltz C. Anatomic investigations of the mechanism of injury and pathologic anatomy of “pulled elbow” in young children. Clin Orthop. 1971;77:134-43. Matles AL, Eliopoulos K. Internal derangement of the elbow in children. Int Surg. 1967;48:259-63. Snellman 0. Subluxation of the head of the radius in children. Acta Orthop Stand. 1959;28:311-15. Costigan PG. Subluxation of the annular ligament af the proximal radio-ulnar joint. Alberta Med Bull. 1952;17:7-9. Illingworth CM. Pulled elbow: a study of 100 patients. Br Med J (Clin Res). 1975;2:672-4. Griffin ME. Subluxation of the head of the radius in children. Pediatr. 1955;15:103. Green JT, Gay FM. Traumatic subluxation of the radial head in
young children. J Bone Joint Surg. 1954;36:655-62. 13. Cone RD. Clues to the initial radiographic evaluation of skeletal trauma. Emerg Med Clin North Am 1984;2:245-78. 14. Quan L, Marcuse EK. The epidemiology and treatment of radial head subluxation. Am J Dis Child 1985;139:1194-7. 15. Miller TO, Insall J. Radial head subluxation in adolescence. NY State J Med. 1975;75:80-2. 16. Frumkin K. Nursemaid’s elbow: a radiographic demonstration. Ann Emerg Med. 1985;14:690-3. 17. Stone CA. Subluxation of the head of the radius. JAMA. 1916;67: 28-9. 18. McVeagh TC. The “slipped elbow” of young children. Calif Med. 1951;74:260. 19. Storen G. Traumatic dislocation of the radial head as an isolated lesion in children. Acta Chir Stand. 1959;116:144-7. 20. DeLee JC, Wilkins KE, Rogers LF, Rockwood CA. Fractureseparation of the distal humeral epiphysis. J Bone Joint Surg. 1980;62:46. 21. Corbett CH. Anterior dislocation of the radius and its recurrence. Br J Surg. 1931;19:155-7. 22. Evans E. Pronation injuries of the forearm with special attention to the anterior Monteggia fracture. clinical experimental study. J Bone Joint Surg. 1949;31B:578-88.
Radial Head Subluxation
269
23. Hamilton W, Parkes JC. Isolated dislocation of the radial head without fracture of the ulna. Clin Orthop. 1973;97:94-6. 24. Hume AC. Anterior dislocation of the head of the radius associated with undisplaced fracture of the olecranon in children. J Bone Joint Surg. 1957;39B:508-12. 25. Lloyd-Roberts GC, Bucknill TM. Anterior dislocation of the radial head in children. J Bone Joint Surg. 1977;59B:402-7. 26. Manske PR. Unreduced isolated radial head dislocation in a child. orthopedics. 1982;5:1327-32. 21. Neviaser RJ, LeFevre GW. Irreducible isolated dislocation of the radial head. Clin Grthop. 1971;80:72-4. 28. Stelling FH, Cote RH. Traumatic dislocation of the head of the radius in children. JAMA. 1956;160:732-6. 29. Vesely DG. Isolated traumatic dislocations of the radial head in
children. Clin Grtbop. 1967;50:31-6. 30. Wiley JJ, Pegington J, Morwich JP. Traumatic dislocation of the radius at the elbow. J Bone Joint Surg. 1974;56B:501-7. 31. Zivkovic S. Traumatic dislocation of the radial head in a 5 year old boy. J Trauma. 1978;18:289-90. 32. Burgess RC, Sprague HH. Post-traumatic posterior radial head subluxation. two case reports. Clin Orthop. 1984;186:192-4. 33. Gleason TF. Traumatic recurrent posterior dislocation of the radial head. Clin Chthop. 1984;184:186-9. 34. Heidt RS, Stem PJ. Isolated posterior dislocation of the radial head. Clin Grthop. 1982;168:136. 35. Salama R, Weintraub S, Weissman SL. Recurrent dislocation of the head of the radius. Clin Grthop. 1977;125:156.
The Journal of Emergency Mechcine, Vol. 8, pp. 265-269, 1990
RADIOGRAPHIC CHANGES WITH RADIAL HEAD SUBLUXATION IN CHILDREN Howard S. Snyder, Reprint address:
MD
Department of Emergency Medicine, Albany Medical Center Hospital, Albany, New York Howard S. Snyder, MD, Department of Emergency Medicine, Albany Medical Center Hospital, 47 New Scotland Avenue, Albany, NY 12208
no radiographic abnormality is identified (1-14). However, radiographic evidence of radial head subluxation consisting of displacement of the radiocapitellar line (RCL) has been noted in several case reports (15,16). Because of these reports of abnormal radiographs with RHS, this study was designed to document radiographic findings in a series of pediatric patients with RHS.
0 Abstract - Radial head subluxation (RIB) produces no radiographic abnormalities according to most experts. However, recent anecdotal case reports have identified displacement of the radiocapitellar line (RCL) in pediatric patients with RIG. To verify thll finding, we retrospectively reviewed all patients less than 5 years of age who received elbow and forearm radiographs in our emergency department. From January 1988 through April 1989, we identified 20 cases of RI-IS. Of the 20 radiographs, 5 (25%) were read by the attending radiologist as abnormal due to RCL displacement indicating subluxation of the radiocapitellar articulation. All 5 of these radiographs had RCL displacement greater than 3 mm. The remaining normal radiographs had RCL displacement less than or equal to 3 mm. The presence of RCL displacement without disruption of the radiocapitellar articulation confirms the diagnosis of RIG, but does not appear to change treatment or outcome in this subset of patients. In addition, radiographs may not be mandatory when the diagnosis of RHS ls certain. We suggest obtaining radiographs lf the history (i.e., fall) or physical examination is atypical or if reduction is unsuccessful to rule out more serious injuries such as radial head dislocation or fracture. 0 Keywords - radial elbow
head; subluxation;
METHODS All radiographs of the elbow and forearm in patients 5 years of age or less obtained in our emergency department (ED) from January 1988 through April 1989 were identified using a computerized file search. Patient records and radiographs were reviewed, including the attending radiologist’s interpretation of the film at the time of presentation. RI-IS was considered present if manipulative reduction in the ED produced return of function in a child presenting with refusal to use the upper extremity. If manipulative reduction was unsuccessful in the ED, RHS was still considered present if the history indicated a pulling mechanism and the child regained normal function either spontaneously or by additional reduction attempts during follow-up. Patients with a clear history of traumatic injury (i.e., fall, motor vehicle accident, direct blow) were excluded from the study. Displacement of the RCL was measured by the author as the distance between the center of the capitellum and a line bisecting the radius distal to the radial tuberosity.
nursemaid’s
INTRODUCTION Radial head subluxation (RHS), also referred to as “nursemaid’s elbow,” is a common pediatric orthopedic emergency occurring in children less than 5 years of age. The diagnosis is made from history and physical examination followed by successful reduction resulting in return of function within minutes. The utility of radiographs is questionable, and most references claim that
RESULTS Twenty ED presentations by 17 patients were identified
meeting study criteria for RHS. Three patients presented
RECEIVED: 18 September 1989; FINAL SUBMISSIONRECEIVED: ACCEPTED: 3 January 1990
20 December 1989;
265
0736-4679/90 $3.00 + .OO
266
Howard S. Snyder
Table 1. Description of study group with abnormal radlographs
Patient 1 2 3 4 5
Age (months) 10 10 13 27 12
RCL Displacement (mm) AP Lateral 5 3 4 4 5.5
4 4.5 2 5 0
DISCUSSION
Reading Abnormal Abnormal Abnormal Abnormal Abnormal
twice during the study period with RHS. One patient presented to the ED the following day after initial reduction of a RI-IS once again refusing to use the same arm. A second attempt at reduction was successful in restoring full range of motion and radiographs were normal on both occasions. Two patients presented 4 months and 16 months after their initial visit with RHS of the opposite extremity and normal radiographs on both occasions. Of the 20 sets of AP and lateral radiographs, 5 sets (25%) showed displacement of the RCL and were read by the attending radiologist as consistent with radial head subluxation. Lateral subluxation was best visualized on the AP view whereas posterior subluxation was evident on the lateral view. Two patients spontaneously reduced during positioning for radiographs. In the remainder of cases, partial or total return of function was noted after manipulation using supination and flexion or extension. Seventeen reductions were successful in the ED whereas 3 reductions were performed during the follow-up examination the next day. No patients were excluded from the study because of unsuccessful reduction, and all radiographs were obtained before attempted reduction. All 5 patients with radiographic evidence of RI-IS were successfully reduced in the ED. Thirteen patients had a history of traction injury whereas 7 patients had no obvious mechanism of injury. Table 1 describes the study population with abnormal radiographs in terms of measured RCL displacement. The 20 sets of radiographs included a total of 52 films (25 AP, 27 lateral), as multiple films were often obtained. Displacement of the RCL in either view was greater than 3 mm in those radiographs considered abnormal. All films with 3 mm or less of displacement of the RCL were read as normal. Although postreduction films were not obtained, one patient (#15) who spontaneously reduced during radiographic examination had RCL displacement of 5 mm and 0 mm on successive lateral films.
RHS results from longitudinal traction applied to the extended forearm of a child. This often occurs during walking, swinging, or pulling the child by the wrist to prevent a fall. The child refuses to use the affected arm which is held in pronation with slight flexion or full extension. No swelling or deformity is present. Although some passive range of motion is allowed, supination and full flexion usually elicit pain. Disruption of the attachment of the annular ligament to the periosteum of the radial head allows the ligament to interpose between the radial head and capitellum (6). Supination and flexion or extension of the affected forearm with pressure over the radial head results in a palpable click and return of function within minutes. Radiographs of RHS are normal according to the pediatric and orthopedic literature, including several textbooks of pediatric radiology (1-14) Although widening of the space between the radial head and capitellum has been suggested (17), it does not appear to be a reliable finding (6,11). Other case reports which claim to show radiographic abnormalities with RI-IS are referred to in the literature, but closer inspection fails to reveal conclusive evidence (18). Although most references continue to state that radiographs in children with RI-IS are normal, we were unable to locate any studies which were able to verify this finding. This study indicates a 25% (5 of 20 patients) incidence of abnormal radiographs with RHS. Excluding the 2 patients who spontaneously reduced during radiographic examination, the incidence of abnormal radiographs increases to 28% (5 to 18 patients). Miller and Insall (15) reported a 16-year-old male with radiographic evidence of posterior radial head subluxation following a longitudinal traction injury which was diagnosed one year after the injury. Recently, Frumkin (16) presented 3 case reports of children with RHS and radiographic evidence of posterior and lateral subluxation of the radial head as shown by displacement of the radiocapitellar line (RCL). The RCL is formed by a line bisecting the proximal radius and should pass through the center of the capitellum in every view (2,19). Because of bowing of the proximal radius, this line should not extend proximal to the radial tuberosity. Displacement of the RCL indicates subluxation or dislocation of the radial head or fracture of the capitellum (20). Although positioning was difficult in many of our patients secondary to pain, the RCL should remain intact in every view (see Figure 1). It is unclear what constitutes abnormal displacement of the RCL as it has never been studied in a series of normal radiographs.
267
Radial Head Subluxation
04 Figure 1 (a) and (b). AP and lateral elbow radiographs show normal radlocaplteilar line (Ilne bisecting the proxlmal radial shaft passes through the center of the capltellum) lndlcatlng a normal artlculatlon between the radial head and humerus.
Several reasons exist for the lack of recognition of radiographic abnormalities with RHS. Radiographs are not obtained in every patient. Some authors suggest that radiographs are not necessary if history and physical examination are typical of RI-IS (2,3,14). Forced supination of the elbow by the radiographic technician during the positioning may reduce the subluxation as evidenced by 2 patients in our study. In addition, a subtle disruption of the RCL may not be recognized by the radiologist unless it is actually measured. Gross displacement of the RCL with loss of the radiocapitellar articulation, as in radial head dislocation (RI-ID), is obvious but it is
Flgure 2 (a) and (b). AP and lateral radlographs wlth dlsplacement of radlocapltellar line by 4 mm (AP) and 5 mm (lateral).
unclear what amount of displacement is significant and may be seen with RHS. Displacement of the RCL of greater than 3 mm was present in those films considered abnormal by the radiologists in our study (see Figure 2). It is unclear whether the RCL was actually measured for each radiograph, and we speculate that less than 3 mm of displacement is not detectable without measurement. Traumatic radial head dislocation (RHD) is a rare entity occurring, both in the pediatric and adult popula-
268
Howard S. Snyder
tion (19,21,35). RHD is usually seen with a proximal ulnar fracture (Monteggia fracture), but may occur as an isolated entity. Although usually resulting from a fall on an outstretched hand or a motor vehicle accident, a case report exists of an adult with an isolated RHD with a longitudinal traction, hyperpronation injury after grabbing a fence while falling (33). These injuries may be more difficult to reduce, requiring closed reduction under general anesthesia or open reduction (25,27, 28,30,32). Immobilization in flexion and supination is recommended for 3 weeks to prevent recurrence, (28,30). Unlike RHS, the annular ligament is ruptured in RI-ID allowing total disruption of the radiocapitellar articulation. It is interesting that Stelling and Cote (28) recommend x-ray studies to differentiate RHD from RI-IS, whereas most references fail to mention RI-ID in their discussion of RI-IS. We suggest obtaining radiographs if the mechanism of injury is unclear or atypical (i.e., fall, direct blow), the physical examination is atypical (i.e., palpable effusion, visible deformity, point tenderness, pain without manipulation), or attempted reduction is unsuccessful. Children with upper extremity injuries from a fall or motor vehicle accident do not have RI-IS but may instead have a traumatic RI-ID, Monteggia fracture-dislocation, supracondy1a.r humerus fracture, or radial head fracture. Therefore, in addition to the RCL, the presence of a “fat pad sign” (displaced fat pads from hemarthrosis and intra-articular fracture, usually an occult radial head fracture) or a displaced “anterior humeral line” (line
along anterior border of humerus should pass through middle third of capitellum) should be searched for in these instances. Thirteen patients were excluded from this study due to history of a fall. Their radiographs revealed 9 fractures of the radius, ulna, and humerus. These entities clearly are much more serious injuries than RI-IS and require different treatment. In summary, radiographic evidence of RI-IS as evidenced by RCL displacement was identified in 25% of the patients in our study. We have identified a subset of pediatric patients with RI-IS and abnormal radiographs, consisting of RCL displacement greater than 3 mm in either view. The history, physical examination, and response to manipulation were similar in this subset of patients with successful reduction in each case. The presence of RCL displacement confirms the diagnosis of radial head subluxation and did not affect treatment or outcome in this group of patients. Based on our review of the literature and our clinical experience, we suggest that radiographs be obtained if the history or physical examination is atypical. This may detect fractures of the radius, ulna, and humerus which require different treatment in the emergency department. When radiographs are obtained, our study suggests they should also be evaluated for RCL displacement.
Acknowledgment- The author would like to thank Barbara Norton and Jaimie Miller for assistance in preparation and Edward C. Geehr, MD, for his review of this manuscript.
REFERENCES 1. Caffey JP. Pediatric x-ray diagnosis. Chicago: Year Book; 1985:
2. 3. 4. 5. 6.
7. 8. 9. 10. 11. 12.
743. Rogers LF. Radiology of skeletal trauma. New York: Churchill Livingstone; 1982:48l-5. Swischuk LB. Emergency radiology of the acutely ill or injured child. Baltimore: Williams and Wilkins; 1986:355-9. Magi1 HK, Aitken AP. Pulled elbow. Surg Gynecol Obstet. 1954;98:753-6. Corrigan AB. The pulled elbow. Med J Aust. 1965;2:187-9. Salter RB, Zaltz C. Anatomic investigations of the mechanism of injury and pathologic anatomy of “pulled elbow” in young children. Clin Orthop. 1971;77:134-43. Matles AL, Eliopoulos K. Internal derangement of the elbow in children. Int Surg. 1967;48:259-63. Snellman 0. Subluxation of the head of the radius in children. Acta Orthop Stand. 1959;28:311-15. Costigan PG. Subluxation of the annular ligament af the proximal radio-ulnar joint. Alberta Med Bull. 1952;17:7-9. Illingworth CM. Pulled elbow: a study of 100 patients. Br Med J (Clin Res). 1975;2:672-4. Griffin ME. Subluxation of the head of the radius in children. Pediatr. 1955;15:103. Green JT, Gay FM. Traumatic subluxation of the radial head in
young children. J Bone Joint Surg. 1954;36:655-62. 13. Cone RD. Clues to the initial radiographic evaluation of skeletal trauma. Emerg Med Clin North Am 1984;2:245-78. 14. Quan L, Marcuse EK. The epidemiology and treatment of radial head subluxation. Am J Dis Child 1985;139:1194-7. 15. Miller TO, Insall J. Radial head subluxation in adolescence. NY State J Med. 1975;75:80-2. 16. Frumkin K. Nursemaid’s elbow: a radiographic demonstration. Ann Emerg Med. 1985;14:690-3. 17. Stone CA. Subluxation of the head of the radius. JAMA. 1916;67: 28-9. 18. McVeagh TC. The “slipped elbow” of young children. Calif Med. 1951;74:260. 19. Storen G. Traumatic dislocation of the radial head as an isolated lesion in children. Acta Chir Stand. 1959;116:144-7. 20. DeLee JC, Wilkins KE, Rogers LF, Rockwood CA. Fractureseparation of the distal humeral epiphysis. J Bone Joint Surg. 1980;62:46. 21. Corbett CH. Anterior dislocation of the radius and its recurrence. Br J Surg. 1931;19:155-7. 22. Evans E. Pronation injuries of the forearm with special attention to the anterior Monteggia fracture. clinical experimental study. J Bone Joint Surg. 1949;31B:578-88.
Radial Head Subluxation
269
23. Hamilton W, Parkes JC. Isolated dislocation of the radial head without fracture of the ulna. Clin Orthop. 1973;97:94-6. 24. Hume AC. Anterior dislocation of the head of the radius associated with undisplaced fracture of the olecranon in children. J Bone Joint Surg. 1957;39B:508-12. 25. Lloyd-Roberts GC, Bucknill TM. Anterior dislocation of the radial head in children. J Bone Joint Surg. 1977;59B:402-7. 26. Manske PR. Unreduced isolated radial head dislocation in a child. orthopedics. 1982;5:1327-32. 21. Neviaser RJ, LeFevre GW. Irreducible isolated dislocation of the radial head. Clin Grthop. 1971;80:72-4. 28. Stelling FH, Cote RH. Traumatic dislocation of the head of the radius in children. JAMA. 1956;160:732-6. 29. Vesely DG. Isolated traumatic dislocations of the radial head in
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