55
Članek prispel / Received
6. 10. 2018
Članek sprejet / Accepted
30. 7. 2020
Naslov za dopisovanje /  
Correspondence
Prim. vis. pred. dr. Teodor Pevec, dr. 
med., svetnik
Kirurški odddelek SB Ptuj
Potrčeva 23- 25, Slovenija
Telefon +386 41650335
E–pošta: teodor.pevec@sb-ptuj.si
Abstract
Purpose: The anterior interosseous ner-
ve (AIN) is a motor branch of the medi-
an nerve that runs deep into the forearm 
where it innervates three muscles. Their 
isolated palsy is known as AIN syndro-
me. Distal forearm fractures are some of 
the most common fractures in children 
and are associated with frequent neuro-
vascular complications. This report descri-
bed a relatively rare complication in our 
everyday medical practice: AIN syndro-
me following a supracondylar fracture.
Case report: A 5-year-old boy fell off 
of a swing and suffered a supracondylar 
fracture. No neurological disorders were 
described. Manual reduction and K-wire 
fixation were performed. At a follow-up 
visit, the mother pointed out that the 
child was unable to flex the thumb of the 
treated arm. We diagnosed the case as 
AIN syndrome.
Conclusion: The AIN syndrome was 
most likely a consequence of the injury to 
the elbow itself. Due to our focus on more 
frequent neurological disorders, especially 
those of the ulnar nerve, AIN syndrome 
Izvleček
Namen: Anteriorni interosalni živec 
(AIŽ) je motorična veja medianega živca 
in poteka globoko v podlakti. Oživčuje tri 
mišice podlakti. Izolirana pareza je zna-
na kot AIŽ sindrom. Pri otrokih so zlomi 
distalnega dela nadlaktnice pogosti prelo-
mi, pri katerih so prav tako pogosto pri-
druženi nevrovaskularni zapleti. V član-
ku prikazujem v naši vsakdanji praksi 
sorazmerno redek zaplet suoprakondilar-
nega preloma z razvojem AIŽ sindroma.
Poro~ilo o primeru: Petletni fant je 
padel z gugalnice in si zlomil nadlaktni-
co. Šlo je za suprakondilarni prelom. Ne-
vrološki izpadi niso bili opisani. Narejeni 
sta bili repozicija in učvrstitev s K žica-
mi. Med kontrolami je mati opozorila, da 
bolnik ne more pokrčiti palca na operira-
ni roki. Prepoznali smo AIŽ sindrom.
Zaklju~ek: Najverjetneje je bil sindrom 
AIŽ posledica poškodbe komolca samega. 
Zavoljo osredotočenosti na pogostejše ne-
vrološke izpade, predvsem ulnarnega živ-
ca, smo razvoj AIŽ zaznali sorazmerno 
pozno. 
Ključne besede: 
poškodba živca, otrok, prelom 
distalne nadlaktnice, zaplet, 
zdravljenje
Key words: 
nerve injury, child, distal humerus 
fracture, complication, treatment
Sindrom anteriornega intraosalnega živca pri otroškem 
suprakondilarnem prelomu nadlaktnice  – prikaz primera
Anterior interosseous nerve syndrome following 
paediatric supracondylar humeral fracture: A case report 
Avtor / Author Teodor Pevec1,2, Simonca Kalšek1,2, Mihael Majerič1,2
Ustanova / Institute 1Splošna bolnišnica dr. Jožeta Potrča Ptuj, Kirurški oddelek, Ptuj, Slovenija; 2Univerza v 
Mariboru, Medicinska fakulteta, Katedra za kirurgijo, Maribor, Slovenija;
1General Hospital dr. Jožeta Potrča Ptuj, Surgery Department, Ptuj, Slovenia; 2University 
of Maribor, Faculty of Medicine, Department for Surgery, Maribor, Slovenia;
Poročilo o primeru/ Case report
ACTA MEDICO-BIOTECHNICA
2020; 13 (2): 55–59
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Poročilo o primeru/ Case report
ACTA MEDICO-BIOTECHNICA
2020; 13 (2): 55–59
was detected relatively late. In preoperative care, and especially 
postoperative care of children with distal forearm fractures, pre-
cise assessments of the patient's neurological status are required 
for the early detection of associated injuries. 
INTRODUCTION
Supracondylar fractures in children account for 16% of 
all paediatric fractures (1). Because both the radial and 
median nerves can be in the vicinity of the fracture line, 
there is a possibility of primary injury to one of these nerves. 
Closed reduction with internal fixation is the primary 
method for managing certain types of supracondylar 
fractures (2). When the wire is placed medially, there is a 
Figure 1. Anteroposterior X-ray of the distal humerus fracture.
danger of damaging the ulnar nerve, 
i.e., a danger of secondary injury to 
the nerve (3).
Anterior interosseous nerve (AIN) 
syndrome is a rare syndrome that 
accounts for <1% of all upper 
extremity palsies (4). The AIN is a 
pure motor branch of the median 
nerve that emerges dorsomedially 
below the elbow, approximately 5–8 
cm distal to the lateral epicondyle, 
and 4 cm distal to the medial 
epicondyle. It innervates three 
forearm muscles: m. flexor pollicis 
longus, m. pronator quadratus, and 
the radial part of m. flexor digitorum 
profundus (5).
Here, we report the case of a patient 
with a distal humeral fracture in 
which AIN syndrome was detected 
relatively late.
CASE PRESENTATION
A 5-year-old boy fell off of a swing 
and presented with a swollen, 
deformed, and severely painful left 
elbow. The child's peripheral pulse was palpable, and he 
could feel all of his fingers. X-ray scans showed a displaced 
supracondylar fracture (Gartland III) with posterolateral 
displacement of the distal fragment (Figure 1). After 
the patient was prepared for surgery, we performed a 
closed reduction and stabilised the fracture using K-wire 
fixation (Figures 2, 3). 
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The patient could feel his fingers after the procedure. 
We feared a possible iatrogenic injury to the ulnar nerve, 
but no signs were found. Finally, the arm was placed in 
a plaster cast.
At follow-up visits, neither the mother nor medical staff 
described any outstanding features in the anamnesis. 
The K-wires were removed 5 weeks after surgery, after 
which the patient started an exercise regime. Mobility 
exercises for the elbow were done successfully, but at the 
first follow-up visit (after 2 months), the mother pointed 
out that the child was unable to flex his thumb. 
Figure 2. Anteroposterior X-ray after ostheosyn-
thesis.
Figure 3. Lateral view X-ray of the distal humerus 
fracture.
Figure 4. Anteroposterior X-ray of the distal hu-
merus fracture, final results.
58 ACTA MEDICO-BIOTECHNICA
2020; 13 (2): 55–59
We performed a clinical examination and found no 
sensory loss in the fingers, but the patient was unable to 
form a circle with his index finger and thumb.
We sought consultation with a neurosurgeon, and 
the patient was scheduled for an electromyography 
and NMR scan. While waiting for these examinations 
(approximately 3 months after the injury), the patient 
regained full mobility of his fingers. His elbow was also 
fully mobile. The X-ray showed that the fracture had 
healed properly (Figures 4, 5).
Figure 5. Lateral view X-ray of the distal humerus 
fracture.
DISCUSSION
Herein, we described the case of a 5-year-old child with 
a distal forearm fracture and an associated neurological 
disorder. Forearm fractures are common, and the 
clinical picture is often dramatic: the sight of a deformed 
extremity, the pain and distress the child suffers, and the 
presence of concerned parents prompt surgeons to take 
immediate action.
Regarding these kinds of forearm fractures in children, 
the relative incidence of associated or iatrogenic injuries 
is quite high, 12–20% (6). Campbell et al. reported that 
the incidence was extremely high for third-degree distal 
forearm fractures in children (7). Damage to the median 
nerve occurred in 50% of these cases, and damage to the 
radial nerve occurred in 28%. They also state that in as 
many as 87% of patients with an associated injury to the 
median nerve, there was posterolateral displacement of 
the distal fragment. These injuries usually occur due to 
the agency of the proximal fragment, while iatrogenic 
injuries occur due to the manipulation required to 
perform the reduction and percutaneous K-wire fixation 
of fractured fragments. The reduction manoeuvres 
themselves can also cause injuries.
Given the fragment displacement, the fracture was 
classified as a third-degree fracture according to 
the Gartland classification (8). We recognised the 
neurological complication late, most likely because we 
were overly focused on the possibility of ulnar nerve 
damage, which can occur during the medial placement of 
K-wire. Patients with AIN syndrome are typically unable 
to form a circle with their index finger and thumb due 
to paralysis of FPL and the radial FDP (impaired flexion 
of the interphalangeal joint of the thumb and the distal 
interphalangeal joint of the index finger).
Regarding the nerve injuries associated with supracondylar 
forearm fractures in children, most studies predict good 
outcomes and a spontaneous return of function within a 
period of 3–5 months (9-11). Thus, most surgeons take 
a “monitor and wait” approach and only plan a surgical 
intervention if nerve function is not regained after a 
specified period of time (3). In our case, spontaneous 
return of nerve function occurred.
In the differential diagnosis of AIN syndrome, a thumb 
flexor injury called stenosing tenosynovitis should be 
considered (12). Previous studies have mentioned that 
a relatively small number of AIN syndrome cases are 
detected by NMR and suggest that electromyography be 
used in diagnosis. Surgical exploration is recommended 
if there is no progress after 3 months of conservative 
treatment, including physical therapy. However, there 
remains a lack of relevant studies to adequately determine 
the most appropriate time for surgical intervention.
CONCLUSION
In the preoperative, and especially in the postoperative 
care of children with distal forearm fractures, precise 
assessments of the patient's neurological status are 
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59ACTA MEDICO-BIOTECHNICA
2020; 13 (2): 55–59
required for the early detection of associated injuries. 
Despite preoperative evaluations being difficult due to 
the child's distress and non-cooperation, an accurate 
neurological status makes postoperative care easier.
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