R a d i o l o g y Ca s e R e p o r t s 1 8 ( 2 0 2 3 ) 1 4 7 7 – 1 4 8 1 Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/radcr Case Report Unilateral congenital proximal radioulnar synostosis in a 4-year-old boy: A case report✩, ✩ ✩ Emmanuel Kobina Mesi Edzie, MD, MBA, FGCPa ,∗ , Klenam Dzefi-Tettey, MD, FWACS, FGCPb , Edmund Kwakye Brakohiapa, MD, FWACS, FGCPc, Nana Ama Amankwa, MBChBd, Amrit Raj, MD, MGCPe, Richard Ato Edzie, BSca , Richard Wono, BScb , Ebenezer Ofori Ampomaning, BScb , Abdul Raman Asemah, BAa, Frank Quarshie, f MSc a Department of Medical Imaging, School of Medical Sciences, College of Health and Allied Sciences, University of Cape Coast, Pedu Interberton Road, Cape Coast, Opposite main gate of Cape Coast Teaching Hospital, Ghana b Department of Radiology, Korle Bu Teaching Hospital, 1 Guggisberg Ave., Accra, Ghana c Department of Radiology, University of Ghana Medical School, Accra, Ghana d Faculty of Internal Medicine, Ghana College of Physicians and Surgeons, Accra, Ghana e Department of Pediatrics, School of Medical Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana f African Institute for Mathematical Sciences (AIMS), Summerhill Estates, East Legon Hills, Santoe, Accra, Ghana a r t i c l e i n f o a b s t r a c t Article history: Congenital radioulnar synostosis is a rare musculoskeletal disorder of the elbow, occurring Received 24 December 2022 as a result of variable degree and length of the congenital fusion of the proximal radioulnar Revised 5 January 2023 joint. Patients presents early to the hospital depending on the severity of the synostosis and Accepted 7 January 2023 its effect on elbow function. It may have psychosocial effects on the affected individuals as Available online 1 February 2023 they grow older especially when the deformity is dramatic. Treatment may be conservative, surgical (which may have a variable degree of success) and psychotherapy. Keywords: © 2023 The Authors. Published by Elsevier Inc. on behalf of University of Washington. Unilateral This is an open access article under the CC BY-NC-ND license Congenital ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ) Proximal Radioulnar synostosis Ghana Introduction Congenital radioulnar synostosis (CRUS) is an uncommon musculoskeletal condition in which the 2 bones of the fore- ✩ Funding: No external funding secured for this manuscript. ✩✩ Competing Interests: The authors have no conflict of interest to dec ∗ Corresponding author. E-mail address: emmanuel.edzie@ucc.edu.gh (E.K.M. Edzie). https://doi.org/10.1016/j.radcr.2023.01.035 1930-0433/© 2023 The Authors. Published by Elsevier Inc. on behalf of U CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4arm; the ulna and the radius, are abnormally connected or fused. This restricts the arm’s ability to rotate, and it is as- sociated with diverse symptom complex. In 1793, Sandifort gave the first account of the condition, and to date, CRUS has been reported in the literature in about 400 cases worldwide lare. niversity of Washington. This is an open access article under the .0/ ) 1478 R a d i o l o g y Ca s e R e p o r t s 1 8 ( 2 0 2 3 ) 1 4 7 7 – 1 4 8 1 Fig. 1 – A picture of a 4-year-old right-sided dominant boy Fig. 2 – (A) AP and (B) lateral radiographs of the left elbow, showing both upper limbs, with an outer angular deformity radius, ulna, and hand bones showing fused radioulnar of the left elbow as shown with the blue arrow. The left bones at the proximal fourth, an absent proximal upper limb looked comparatively shorter. radioulnar joint and a postero-medial orientation of the olecranon process (yellow arrows). [1] . This X-linked dominant condition usually affects both el- bows and has a paternal pattern of inheritance. However, the precise etiology is still unknown, and neither the diagnosis nor the course of treatment has been agreed upon hence, there is no gold standard for the treatment of congenital proximal ra- dioulnar synostosis [2] . Treatment is usually conservative as surgical interventions rarely succeed. But when required, ra- dioulnar rotation osteotomy is popular, but it comes with a high risk of ischemic muscle contracture, nerve damage, de- layed union, and necessitates a lengthy period of forearm im- mobilization following surgery [ 3 ,4 ]. We present a case of a 4- year-old boy diagnosed with congenital left proximal radioul- nar synostosis. Case presentation We report a case of a 4-year-old boy, who was brought to our radiology department by the mother for an upper limb radio- graph on account of a left elbow joint deformity and inability to turn the left elbow joint to the side. He has had this condition since birth, but it is more promi- nent as he grows older from the narration of the mother. There was no history of trauma and no family history of this condi- tion. The mother said the contemporaries of her son had been teasing him with this deformity and thought this was reduc-ing the self-esteem of the child at this age because he had been refusing to go out to play with his friends, even though he does not complain about the affected elbow to her. On physical examination, he looked clinically well, with normal respiratory, cardiovascular, central nervous, and gas- trointestinal systems. There was an obvious left elbow defor- mity compared to the dominant right side and an outer orien- tation of his left elbow during the examination of the muscu- loskeletal system. The affected forearm looked shorter than the dominant right one ( Fig. 1 ). The child could not supinate and pronate but could flex and extend the ipsilateral elbow joint. Radiographs of the left elbow, radius and ulna bones showed fused radioulnar bones at the proximal fourth, and an absent proximal radioulnar joint on the antero-posterior (AP) and lateral views, with a postero-medial orientation of the ole- cranon process ( Figs. 2 A and B). The rest of the left radius and ulna bones, distal to the defect and the distal radioulnar joint on the left looked normal but shorter compared to the right ( Fig. 3 ). A diagnosis of a congenital left proximal radioulnar synostosis was made. A comparative radiograph of the right upper limb showed no abnormality ( Figs. 4 A and B). The child was then referred to the pediatric orthopedic unit of our hospital for further management, where a conservative management plan was started as the orthopedic surgeon de- cided that from literature surgical interventions are usually R a d i o l o g y Ca s e R e p o r t s 1 8 ( 2 0 2 3 ) 1 4 7 7 – 1 4 8 1 1479 Fig. 4 – (A) AP and (B) lateral radiographs showing normal bones of the right elbow, radius and ulna, wrist and hand. Fig. 3 – AP radiographs showing both elbows; radius and ulna bones; and both wrists and hands bones with a comparatively shorter left radius and ulna. It also shows fused proximal quarter (red arrow) but normal distal 3 quarters of the left radius and ulna bones with a normal left distal radioulnar joint (yellow arrow). unsuccessful. The patient is also being seen by the clinical psychologist in order to assist him build self-confidence as he grows with this deformity. He is currently doing well. Permis- sion was sought from the parents after thorough explanation of the condition to them, to write the case for publication, with the assurance of complete anonymity and confidentiality. Discussion Congenital proximal radioulnar synostosis is a rare disorder of the elbow which can be functionally tolerable by the patient in most cases when not severe. It can be associated with other musculoskeletal congenital conditions like syndactyly, poly- dactyly, congenital hip dislocation or clubfeet, which is not the condition of our patient. According to literature, CRUS is usu- ally diagnosed before 5 years of age, and it is bilateral in about 60%-80% of cases, with a comparatively higher incidence in males [ 1 ,2 ]. In our case, even though the patient was less than 5 years, his condition was unilateral ( Figs. 1 and 3 ). CRUS causes variable degree of fusion of the proximal ra- dioulnar joint and the fusion (synostosis) presents in vary-ing lengths, which may involve the radial head or not. This congenital condition can be divided into types depending on its relation with the proximal radioulnar junction; Type I in- volves a complete fusion of the bones proximally with the fusion occurring for a variable distance, but Type II involves a partial union and it is related variably with the area distal to the proximal epiphysis of the radial head as described by Wilkie [5] , and Simmons et al. [6] . CRUS was further described into 4 types by Cleary and Omer [7] as fibrous synostosis, bony synostosis, association with posterior dislocation of the radius and association with anterior dislocation of the radius. In our case, there was complete synostosis involving the bones and therefore classified as Wilkie Type I and affecting the proximal fourth of the left radius and ulnar ( Fig. 2 ). Our patient had a shorter left upper arm and forearm be- cause of shortening of the left humerus and radius and ulna bones respectively ( Figs. 1 and 5 ). This has also been reported in a study by Yammine et al. [8] . It can also be noted that radioulnar synostosis may occur as a result of trauma, termed as post traumatic radioulnar syn- ostosis. Post-traumatic radioulnar synostosis may involve the distal forearm (the rarest), mid-forearm, and proximal fore- arm [3] . The current case report did not have any history of trauma and the deformity was noticed right from birth con- sistent with CRUS. Literature has reported that CRUS may be associated with psychosocial problems as the child grows which may affect the patient’s self-esteem resulting in depression, violent be- havior, anxiety, and problems with relationships [9] . In this 1480 R a d i o l o g y Ca s e R e p o r t s 1 8 ( 2 0 2 3 ) 1 4 7 7 – 1 4 8 1 Fig. 5 – Radiographs (AP) of both upper limbs showing a shorter left upper limb as a result of comparatively shorter humerus, radius and ulna bones with the osseous synostosis on the left. patient, there was low self-esteem hence, the need for psy- chotherapy. Conclusion CRUS is rare but when present and severe can affect the mo- bility of the elbow and interfere with the daily activities of the affected individual. This therefore requires early diagnosis so that the appropriate multidisciplinary interventions are put in place to minimize the debilitating effects of CRUS. Patient consent Informed consent was obtained from the patient’s parents and anonymity and confidentiality were ensured. Acknowledgment We are thankful to the parents of the boy for giving consent for this case report to be written. R E F E R E N C E S [1] Iyoko IK, Iyoko II, Essien MA, Henshaw JE. 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