Vol. 17A, No. 5 September 1992
THE JOURNAL OF HAND SURGERY
3. Mulliken JB, Glowacki J. Hemangiomas and vascular malformations in infants and children: a classification based on endothelial characteristics. Plast Reconstr Surg 1982;69:413-20. 4. Sabin FR. Origin and development of the primitive vessels of the chick and of the pig. Contrib Embryo1 1917;6:61-124. 5. Kiippel M, Trenaunay P. Du Nocvns variqueux osteohypertrophique. Arch Gen Med 1990;3:641. in connection with hy6. Weber FP. Angioma-formation pertrophy of limbs and hemi-hypertrophy. Br J Dermatol 1907;19:231-5. 7. Weher FP. Haemangiectatic hypertrophy of limbs-con-
9. 10.
11.
12.
genital phlebarteriectasis and so-called congenital varicose veins. Br J Child Dis 1918;15:13-7. 8. Holman E. Abnormal arteriovenous communications: great variability of effects with particular reference to
13.
delayed development of cardiac failure. Circulation 1965;32:1001-9. Gelberman RH, Goldner JL. Congenital arteriovenous fistulas of the hand. J HAND SURC 1978;3:451-4. Maffucci A. Di un case di encondroma ed angioma multiplo contribuzione al a genesi embrionale dei tumor. Mov Med Chir 1881;3:399. Osler W. On a family form of recurring epistaxis, associated with multiple telangiectases of the skin and mucous membranes. Johns Hopkins Hosp Bull 1901;12: 333-7. Weber FP. Multiple hereditary developmental angiomata (telangiectases) of the skin and mucous membranes associated with recurring haemorrhages. Lancet 1907: 2: 160-2. Bean WB. Vascular spiders and related lesions of the skin. Springfield, Illinois, Charles C. Thomas, 1958.
Radial head dislocations in children with below-elbow deficiencies Two thirds of the children who have below-elbow deficiencies, congenital or acquired, have concomitant radial head dislocations. The direction of the dislocation depends largely on the length of the residual limb. The dislocation does not require specific surgical treatment and rarely necessitates prosthetic modification. (J HAND SURC 1992;17A:891-5.)
Gregory J. Menio, MD, ad
Steven M. Wenner, MD, Springfield,
R adial head dislocation
may occur as an isolated congenital anomaly or in conjunction with a variety of other upper limb and/or generalized skeletal disorders. ‘-’ There has been one previous report in the literature of radial head dislocations occurring in conjunction with transverse deficiency of the forearm.‘*’ We report our ongoing experience with the condition.
Received for publication Sept. 27, 1991; accepted in revised form Jan. 15, 1992. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Steven M. Wenner, MD, 300 Carew St., Springfield, MA 01104. 3/1136X26
Mass.
Material and methods We reviewed the hospital charts, x-ray films, and prosthetic department records of all patients treated in the Upper Limb Deficiency Clinic at the Springfield unit of the Shriners Hospital for Crippled Children. Seventy-five patients with 76 affected limbs were selected for further review on the basis of the following criteria: ( 1) transverse deficiency or acquired amputation distal to the elbow (forearm, wrist, metacarpal); (2) adequate records and x-ray films for complete evaluation. Patients were divided into two groups: those whose deficiency was congenital and those in whom it was acquired. Information was gathered concerning gender, side of affected limb, ratio of length of residual affected limb to length of contralateral normal limb, and difficulty with adjustments in fitting of prosthesis. In the
891
892
The Journal of HAND SURGERY
Menio and Wenner
Fig. 1. Direct anterior dislocation
Fig. 2. Lateral dislocation
of radial head in very short congenital below-elbow
of radial head in intermediate-length
congenital below-elbow
deficiency.
deficiency.
Vol. 17A, No. 5 September I992
Fig. 3. Posterior dislocation
Radial head dislocations
of radial head in association
group with acquired deficiency, mechanism of loss and age at which the loss occurred were noted. X-ray films were studied for level of deficiency, presence of radial head dislocation or subluxation, and direction of such dislocation. From the records of the prosthetics department, we determined the ratio of the length of the affected limb to the length of the unaffected limb. Measurement was done from the olecranon tip to the ulnar styloid. In one patient who had bilateral traumatic amputations, length ratio was approximated by means of anthropometric tables. Difficulties with socket fit, particularly those that might be attributable to a dislocated prominent radial head, were noted.
Results The congenital-deficiency group consisted of 62 patients (28 boys and 34 girls) with 62 affected limbs. The left/right ratio was 40: 22. There were 42 patients with transverse deficiency of the forearm, partial (TDFP); 10 patients with transverse deficiency of the carpus, complete (TDCC); 8 with transverse deficiency of the carpus, partial (TDCP); and 2 with transverse deficiency of the metacarpals (1 complete, 1 partial: TDMC , TDMP) . An x-ray review of the radiocapitellar articulation demonstrated that 42 patients had a dislocation of this
893
with proximal radioulnar synostosis.
joint, 3 had a subluxation (articulation greater than 50% but less than lOO%), and 17 had normal alignment. The overall incidence of dislocation was 67%. The incidence of dislocation and subluxation was 73%. Forty-two of the 62 patients in the congenital-deficiency group had transverse deficiency of the forearm. Of these, 36 had a dislocated radial head and two had a subluxation; only 4 had a normal articulation of this joint. Therefore, in this subgroup, the rate of dislocation/ subluxation was 90%. Conversely, in the subgroup of patients who had congenital deficiency at a more distal level (TDCC, TDCP, TDMC, TDMP), the dislocation/subluxation rate was 35%. Among the 42 patients with TDFP and a dislocated radial head, there were 10 anterior dislocations, 10 anterolateral dislocations, 17 lateral dislocations, and 1 posterior dislocation (Figs. 1 and 2). Of the 10 patients with TDCC, 4 had lateral dislocations, and 1 had a posterior dislocation. Two of the 8 patients with TDCP had anterolateral dislocations. There were no dislocations in patients with a complete or partial transverse deficiency through the metacarpals. Both posterior dislocations occurred in patients who had concomitant proximal radioulnar synostosis ( Fig. 3). The direction of the radial head dislocation varied according to the length of the residual limb. Patients
894
The Journal of HAND SURGERY
Menio and Wenner
Table I. Ratio of residual length of amputated forearm to length of normal forearm
Direction of dislocation
0.44 0.44 0.44 0.45 0.46 0.48 0.48 0.49 0.50 0.51
Fig. 4. Socket modification to accommodate prominent radial
head.
with the shortest residual limbs generally had an anterior dislocation of the radial head. Patients who had the longest residual limbs tended to have a lateral dislocation. Patients in whom the residual limbs were of intermediate length most commonly had an anterolatera1 dislocation (Table I). In the 62 patients with congenital deficiencies, only one of the 45 patients with dislocated radial heads required prosthetic modification because of the dislocation; in that case the socket had to be ground down to accommodate the prominent radial head (Fig. 4). In the group with acquired below-elbow amputations, there were 13 patients (11 boys and 2 girls) with 14 affected limbs. The right/left ratio was 9 : 5. The mechanism of injury included electrical burn in 5 patients, other injuries in 6 patients, and single cases of ischemia, infection, and tumor. There were 12 below-elbow amputations and 2 wrist disarticulations. Three limbs had radiocapitellar dislocation and 2 had subluxation of this joint (each with an articulation of 75%). Nine limbs had normally aligned radiocapitellar joints. Two of the 3 dislocations were anterolateral, and 1 was anterior. Both subluxations were lateral in direction. The average age at the time of loss for those patients with dislocation or subluxation was 7 months, whereas the average age at the time of loss for those patients who had reduced radiocapitellar joints was 9 years. No patient in the group with acquired limb deficiency required special prosthetic modification.
Discussion In 1970 Kruger and Breyan’ reported the occurrence of radial head dislocation in children with transverse partial hemimelia (TDFP). There were 13 dislocations
0.53 0.57 0.58 0.58 0.62 0.62 0.64 0.81 0.90 0.13 0.19 0.23 0.25 0.26 0.26 0.33 0.33 0.35 0.38 0.40 0.40 0.40 0.40 0.41 0.41 0.42 0.42 0.42 0.43 0.43 Key: A = anterior; L = lateral; AL = anterolateral; Blank = Radiocapitellar joint reduced.
AL AL L AL L L L AL L L AL L L L L AL L AL L A A AL A A A A A A A L P L AL L AL A L P = posterior;
in the 16 limbs they evaluated, for a dislocation rate of 81%. Our dislocation rate in the patients with TDFP was 86%. Kruger and Breyan did not specify the direction of the dislocation or the ratio of the length of the residual limb to the length of the affected limb. As noted, our results indicate that the direction of dislocation was related to the ratio of the length of the residual limb to that of the normal limb. Lower ratios (seen in patients with shorter residual
Vol. 17A, No. 5 September 1992
limbs) are associated with anterior dislocation, and higher ratios are associated with lateral dislocation. There was a 30% incidence of radial head dislocation in patients with deficiencies through the wrist or hand. Dislocation of the radial head may follow trauma to the elbow or forearm. However, no previous study has reported such dislocations after traumatic amputation through the forearm or distally in the absence of direct injury to the radiocapitellar and proximal radioulnar articulations. That is, developmental dislocation of the radial head after amputation through the forearm has not been previously described. In our series of 14 acquired amputations distal to the elbow, there was a 57% of incidence of dislocation/subluxation of the radial head. Why do these radial heads dislocate? Limb development occurs between the fourth and sixth weeks of gestation. Limb deficiency occurs at this same time, as a result of vascular occlusion, band constriction (Streeter’s dysplasia), toxin, or other factors. Such congenital limb deficiency disrupts the soft tissue balance that helps to stabilize the elbow and forearm articulations. Kruger and Breyan’ pointed out that the biceps is the major deforming force that causes anterior dislocation of the radial head. Elbow flexion and forearm supination follow contraction of the biceps brachii muscle. The resultant vector of force is anteriorly directed. We hypothesize that this force vector is balanced in the normal limb by local static forces, including the elbow capsule, the proximal and distal radioulnar joint capsules, and the annular and interosseous ligaments. Local dynamic forces that counterbalance the pull of the biceps muscle are the triceps, the supinator, and the pronator teres muscles. Further analysis led us to conclude that the absence of adequate static and dynamic proximal radial stabilizers explains the radial head dislocations that we observed. X-ray films demonstrate apparently normal configurations of the proximal end of the radius and ulna and the distal end of the humerus; however, subtle abnormalities in the bony architecture might also contribute to this problem. The biceps muscle, unopposed by any dynamic stabilizer other than the weaker triceps muscle, causes direct anterior dislocation of the radial head in the very short residual limb of a below-elbow amputee. In the patient with a residual limb of intermediate length, the supinator unrolls the radius and pulls the proximal end laterally. The vector that results from the combined anteriorly directed pull of the biceps and laterally directed pull of the supinator causes an anterolateral dis-
Radial head dislocations
895
location of the radial head. In the patient with a longer residual limb, it is presumably the additional force of the pronator teres that results in the high incidence of lateral dislocations of the radial head. Children who sustain below-elbow amputations at an early age are at risk of dislocation of the radial head. In these children the dynamic stabilizers are destroyed, and the static stabilizers are inadequate to fully support the radiocapitellar and proximal radioulnar articulations. Conversely, in those children who sustain the loss of a limb at an older age, the static stabilizers are strong enough to prevent the ongoing muscle imbalance from causing a dislocation of the radial head. Finally, factors related to prosthesis wear or use, such as age at initial fitting, habitual nonuse, or frank rejection of the prosthesis, do not influence the occurrence or direction of radial head dislocation. Once we began to study this abnormality, we frequently noted its presence at the time of initial patient evaluation in our limbdeficiency clinic, typically in the first 6 months of life. With this knowledge and our conclusion that the imbalance of static and dynamic stabilizers of the radius accounts for the dislocation, we have chosen not to attempt orthotic, prosthetic, or surgical measures to prevent radial head dislocation when there are no prosthesis-fitting or elbow function problems secondary to the dislocation.
REFERENCES 1. Baldwin DM, Weiner DS. Congenital bowing and intraosseous neurofibroma of the ulna. J Bone Joint Surg 1974;56A:803-7. 2. Bayne LG, Costas BL. Malformations of the upper limb. In: Pediatric orthopedics. Philadelphia: JB Lippincott, 1990563-609. 3. Frantz CH, O’Rahilly R. Congenital skeletal limb deficiencies. J Bone Joint Surg 1961;43A: 1202-24. 4. Mardam-Bey T, Ger E. Congenital radial-head dislocation. J HAND SURG 1979;4:316-20. 5. McFarland B. Congenital dislocation of the head of the radius. Br J Surg 1936;24:41-9. 6. Mital MA. Congenital radioulnar synostosis and congenital dislocation of the radial head. Orthop Clin North Am 1976;7:375-83. 7. Wilkie DPD. Congenital radioulnar synostosis. Br J Surg 1914;1:366-75. 8. Kruger LM, Breyan NR. A study of radial-head dislocation in children with transverse partial hemimelia of the upper limb. Inter-Clinic Information Bulletin 197O;lO: l-4. 9. Swanson AB. A classification for congenital limb malformation. J HAND SURG 1976;1:8-22.
THE JOURNAL OF HAND SURGERY
3. Mulliken JB, Glowacki J. Hemangiomas and vascular malformations in infants and children: a classification based on endothelial characteristics. Plast Reconstr Surg 1982;69:413-20. 4. Sabin FR. Origin and development of the primitive vessels of the chick and of the pig. Contrib Embryo1 1917;6:61-124. 5. Kiippel M, Trenaunay P. Du Nocvns variqueux osteohypertrophique. Arch Gen Med 1990;3:641. in connection with hy6. Weber FP. Angioma-formation pertrophy of limbs and hemi-hypertrophy. Br J Dermatol 1907;19:231-5. 7. Weher FP. Haemangiectatic hypertrophy of limbs-con-
9. 10.
11.
12.
genital phlebarteriectasis and so-called congenital varicose veins. Br J Child Dis 1918;15:13-7. 8. Holman E. Abnormal arteriovenous communications: great variability of effects with particular reference to
13.
delayed development of cardiac failure. Circulation 1965;32:1001-9. Gelberman RH, Goldner JL. Congenital arteriovenous fistulas of the hand. J HAND SURC 1978;3:451-4. Maffucci A. Di un case di encondroma ed angioma multiplo contribuzione al a genesi embrionale dei tumor. Mov Med Chir 1881;3:399. Osler W. On a family form of recurring epistaxis, associated with multiple telangiectases of the skin and mucous membranes. Johns Hopkins Hosp Bull 1901;12: 333-7. Weber FP. Multiple hereditary developmental angiomata (telangiectases) of the skin and mucous membranes associated with recurring haemorrhages. Lancet 1907: 2: 160-2. Bean WB. Vascular spiders and related lesions of the skin. Springfield, Illinois, Charles C. Thomas, 1958.
Radial head dislocations in children with below-elbow deficiencies Two thirds of the children who have below-elbow deficiencies, congenital or acquired, have concomitant radial head dislocations. The direction of the dislocation depends largely on the length of the residual limb. The dislocation does not require specific surgical treatment and rarely necessitates prosthetic modification. (J HAND SURC 1992;17A:891-5.)
Gregory J. Menio, MD, ad
Steven M. Wenner, MD, Springfield,
R adial head dislocation
may occur as an isolated congenital anomaly or in conjunction with a variety of other upper limb and/or generalized skeletal disorders. ‘-’ There has been one previous report in the literature of radial head dislocations occurring in conjunction with transverse deficiency of the forearm.‘*’ We report our ongoing experience with the condition.
Received for publication Sept. 27, 1991; accepted in revised form Jan. 15, 1992. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Steven M. Wenner, MD, 300 Carew St., Springfield, MA 01104. 3/1136X26
Mass.
Material and methods We reviewed the hospital charts, x-ray films, and prosthetic department records of all patients treated in the Upper Limb Deficiency Clinic at the Springfield unit of the Shriners Hospital for Crippled Children. Seventy-five patients with 76 affected limbs were selected for further review on the basis of the following criteria: ( 1) transverse deficiency or acquired amputation distal to the elbow (forearm, wrist, metacarpal); (2) adequate records and x-ray films for complete evaluation. Patients were divided into two groups: those whose deficiency was congenital and those in whom it was acquired. Information was gathered concerning gender, side of affected limb, ratio of length of residual affected limb to length of contralateral normal limb, and difficulty with adjustments in fitting of prosthesis. In the
891
892
The Journal of HAND SURGERY
Menio and Wenner
Fig. 1. Direct anterior dislocation
Fig. 2. Lateral dislocation
of radial head in very short congenital below-elbow
of radial head in intermediate-length
congenital below-elbow
deficiency.
deficiency.
Vol. 17A, No. 5 September I992
Fig. 3. Posterior dislocation
Radial head dislocations
of radial head in association
group with acquired deficiency, mechanism of loss and age at which the loss occurred were noted. X-ray films were studied for level of deficiency, presence of radial head dislocation or subluxation, and direction of such dislocation. From the records of the prosthetics department, we determined the ratio of the length of the affected limb to the length of the unaffected limb. Measurement was done from the olecranon tip to the ulnar styloid. In one patient who had bilateral traumatic amputations, length ratio was approximated by means of anthropometric tables. Difficulties with socket fit, particularly those that might be attributable to a dislocated prominent radial head, were noted.
Results The congenital-deficiency group consisted of 62 patients (28 boys and 34 girls) with 62 affected limbs. The left/right ratio was 40: 22. There were 42 patients with transverse deficiency of the forearm, partial (TDFP); 10 patients with transverse deficiency of the carpus, complete (TDCC); 8 with transverse deficiency of the carpus, partial (TDCP); and 2 with transverse deficiency of the metacarpals (1 complete, 1 partial: TDMC , TDMP) . An x-ray review of the radiocapitellar articulation demonstrated that 42 patients had a dislocation of this
893
with proximal radioulnar synostosis.
joint, 3 had a subluxation (articulation greater than 50% but less than lOO%), and 17 had normal alignment. The overall incidence of dislocation was 67%. The incidence of dislocation and subluxation was 73%. Forty-two of the 62 patients in the congenital-deficiency group had transverse deficiency of the forearm. Of these, 36 had a dislocated radial head and two had a subluxation; only 4 had a normal articulation of this joint. Therefore, in this subgroup, the rate of dislocation/ subluxation was 90%. Conversely, in the subgroup of patients who had congenital deficiency at a more distal level (TDCC, TDCP, TDMC, TDMP), the dislocation/subluxation rate was 35%. Among the 42 patients with TDFP and a dislocated radial head, there were 10 anterior dislocations, 10 anterolateral dislocations, 17 lateral dislocations, and 1 posterior dislocation (Figs. 1 and 2). Of the 10 patients with TDCC, 4 had lateral dislocations, and 1 had a posterior dislocation. Two of the 8 patients with TDCP had anterolateral dislocations. There were no dislocations in patients with a complete or partial transverse deficiency through the metacarpals. Both posterior dislocations occurred in patients who had concomitant proximal radioulnar synostosis ( Fig. 3). The direction of the radial head dislocation varied according to the length of the residual limb. Patients
894
The Journal of HAND SURGERY
Menio and Wenner
Table I. Ratio of residual length of amputated forearm to length of normal forearm
Direction of dislocation
0.44 0.44 0.44 0.45 0.46 0.48 0.48 0.49 0.50 0.51
Fig. 4. Socket modification to accommodate prominent radial
head.
with the shortest residual limbs generally had an anterior dislocation of the radial head. Patients who had the longest residual limbs tended to have a lateral dislocation. Patients in whom the residual limbs were of intermediate length most commonly had an anterolatera1 dislocation (Table I). In the 62 patients with congenital deficiencies, only one of the 45 patients with dislocated radial heads required prosthetic modification because of the dislocation; in that case the socket had to be ground down to accommodate the prominent radial head (Fig. 4). In the group with acquired below-elbow amputations, there were 13 patients (11 boys and 2 girls) with 14 affected limbs. The right/left ratio was 9 : 5. The mechanism of injury included electrical burn in 5 patients, other injuries in 6 patients, and single cases of ischemia, infection, and tumor. There were 12 below-elbow amputations and 2 wrist disarticulations. Three limbs had radiocapitellar dislocation and 2 had subluxation of this joint (each with an articulation of 75%). Nine limbs had normally aligned radiocapitellar joints. Two of the 3 dislocations were anterolateral, and 1 was anterior. Both subluxations were lateral in direction. The average age at the time of loss for those patients with dislocation or subluxation was 7 months, whereas the average age at the time of loss for those patients who had reduced radiocapitellar joints was 9 years. No patient in the group with acquired limb deficiency required special prosthetic modification.
Discussion In 1970 Kruger and Breyan’ reported the occurrence of radial head dislocation in children with transverse partial hemimelia (TDFP). There were 13 dislocations
0.53 0.57 0.58 0.58 0.62 0.62 0.64 0.81 0.90 0.13 0.19 0.23 0.25 0.26 0.26 0.33 0.33 0.35 0.38 0.40 0.40 0.40 0.40 0.41 0.41 0.42 0.42 0.42 0.43 0.43 Key: A = anterior; L = lateral; AL = anterolateral; Blank = Radiocapitellar joint reduced.
AL AL L AL L L L AL L L AL L L L L AL L AL L A A AL A A A A A A A L P L AL L AL A L P = posterior;
in the 16 limbs they evaluated, for a dislocation rate of 81%. Our dislocation rate in the patients with TDFP was 86%. Kruger and Breyan did not specify the direction of the dislocation or the ratio of the length of the residual limb to the length of the affected limb. As noted, our results indicate that the direction of dislocation was related to the ratio of the length of the residual limb to that of the normal limb. Lower ratios (seen in patients with shorter residual
Vol. 17A, No. 5 September 1992
limbs) are associated with anterior dislocation, and higher ratios are associated with lateral dislocation. There was a 30% incidence of radial head dislocation in patients with deficiencies through the wrist or hand. Dislocation of the radial head may follow trauma to the elbow or forearm. However, no previous study has reported such dislocations after traumatic amputation through the forearm or distally in the absence of direct injury to the radiocapitellar and proximal radioulnar articulations. That is, developmental dislocation of the radial head after amputation through the forearm has not been previously described. In our series of 14 acquired amputations distal to the elbow, there was a 57% of incidence of dislocation/subluxation of the radial head. Why do these radial heads dislocate? Limb development occurs between the fourth and sixth weeks of gestation. Limb deficiency occurs at this same time, as a result of vascular occlusion, band constriction (Streeter’s dysplasia), toxin, or other factors. Such congenital limb deficiency disrupts the soft tissue balance that helps to stabilize the elbow and forearm articulations. Kruger and Breyan’ pointed out that the biceps is the major deforming force that causes anterior dislocation of the radial head. Elbow flexion and forearm supination follow contraction of the biceps brachii muscle. The resultant vector of force is anteriorly directed. We hypothesize that this force vector is balanced in the normal limb by local static forces, including the elbow capsule, the proximal and distal radioulnar joint capsules, and the annular and interosseous ligaments. Local dynamic forces that counterbalance the pull of the biceps muscle are the triceps, the supinator, and the pronator teres muscles. Further analysis led us to conclude that the absence of adequate static and dynamic proximal radial stabilizers explains the radial head dislocations that we observed. X-ray films demonstrate apparently normal configurations of the proximal end of the radius and ulna and the distal end of the humerus; however, subtle abnormalities in the bony architecture might also contribute to this problem. The biceps muscle, unopposed by any dynamic stabilizer other than the weaker triceps muscle, causes direct anterior dislocation of the radial head in the very short residual limb of a below-elbow amputee. In the patient with a residual limb of intermediate length, the supinator unrolls the radius and pulls the proximal end laterally. The vector that results from the combined anteriorly directed pull of the biceps and laterally directed pull of the supinator causes an anterolateral dis-
Radial head dislocations
895
location of the radial head. In the patient with a longer residual limb, it is presumably the additional force of the pronator teres that results in the high incidence of lateral dislocations of the radial head. Children who sustain below-elbow amputations at an early age are at risk of dislocation of the radial head. In these children the dynamic stabilizers are destroyed, and the static stabilizers are inadequate to fully support the radiocapitellar and proximal radioulnar articulations. Conversely, in those children who sustain the loss of a limb at an older age, the static stabilizers are strong enough to prevent the ongoing muscle imbalance from causing a dislocation of the radial head. Finally, factors related to prosthesis wear or use, such as age at initial fitting, habitual nonuse, or frank rejection of the prosthesis, do not influence the occurrence or direction of radial head dislocation. Once we began to study this abnormality, we frequently noted its presence at the time of initial patient evaluation in our limbdeficiency clinic, typically in the first 6 months of life. With this knowledge and our conclusion that the imbalance of static and dynamic stabilizers of the radius accounts for the dislocation, we have chosen not to attempt orthotic, prosthetic, or surgical measures to prevent radial head dislocation when there are no prosthesis-fitting or elbow function problems secondary to the dislocation.
REFERENCES 1. Baldwin DM, Weiner DS. Congenital bowing and intraosseous neurofibroma of the ulna. J Bone Joint Surg 1974;56A:803-7. 2. Bayne LG, Costas BL. Malformations of the upper limb. In: Pediatric orthopedics. Philadelphia: JB Lippincott, 1990563-609. 3. Frantz CH, O’Rahilly R. Congenital skeletal limb deficiencies. J Bone Joint Surg 1961;43A: 1202-24. 4. Mardam-Bey T, Ger E. Congenital radial-head dislocation. J HAND SURG 1979;4:316-20. 5. McFarland B. Congenital dislocation of the head of the radius. Br J Surg 1936;24:41-9. 6. Mital MA. Congenital radioulnar synostosis and congenital dislocation of the radial head. Orthop Clin North Am 1976;7:375-83. 7. Wilkie DPD. Congenital radioulnar synostosis. Br J Surg 1914;1:366-75. 8. Kruger LM, Breyan NR. A study of radial-head dislocation in children with transverse partial hemimelia of the upper limb. Inter-Clinic Information Bulletin 197O;lO: l-4. 9. Swanson AB. A classification for congenital limb malformation. J HAND SURG 1976;1:8-22.
