Transepiphyseal separation of distal humerus: A case report and review of literature

Transepiphyseal Fracture of Distal Humerus ( TFDH ) or epiphysiolysis of distal humerus is a rare injury seen in children younger than three years of age [1]. It is the least commonest of all physeal injuries representing 3.9% of them in this age group [2]. The reported incidence of this injury is 1:35000 births [3]. The diagnosis of this condition is very challenging and in particular differentiating it from elbow dislocation is very diffi cult. Plain radiographs are not decisive since ossifi cation centers around elbow are not ossifi ed during this age group.


Introduction
Transepiphyseal Fracture of Distal Humerus ( TFDH ) or epiphysiolysis of distal humerus is a rare injury seen in children younger than three years of age [1]. It is the least commonest of all physeal injuries representing 3.9% of them in this age group [2]. The reported incidence of this injury is 1:35000 births [3]. The diagnosis of this condition is very challenging and in particular differentiating it from elbow dislocation is very diffi cult. Plain radiographs are not decisive since ossifi cation centers around elbow are not ossifi ed during this age group.

Case report
A one year old male child was brought to accident and emergency by his parents with Alleged history of fall a few hours back resulting in trauma to his left elbow presenting as pain , swelling and limitation of left elbow movements . Initial X rays of left elbow suggested TFDH .He was seen by on call orthopedic surgeon who treated it by closed reduction and above elbow plaster slab in 100 degrees fl exion (Figures 1,2). On injury include birth injuries (emergency caesarian sections and vaginal deliveries ) child abuse , falls and direct trauma [3,5]. Traumatic separation of epiphysis results from rotator shearing forces with fracture commonly extension type with distal epiphysis lying posterior to metaphysis [6].

TFDH has been classifi ed into three groups as per Delees classifi cation
Group A :TFDH (seen in infants upto12 months age) before the secondary ossifi cation centre of the Capitellum appears without metaphyseal spike usually Salter Harris ( SH )Type 1 physis injury. Ultrasonography (USG) is a non invasive diagnostic procedure to differentiate elbow dislocation from distal humeral epiphysiolysis . The cartilaginous epiphysis appears as a hypoechogenic structure while the bones appear as highly echogenic structure. Moreover periosteal reaction can be seen as early as 7-10 days after injury confi rming the diagnosis [3].
However the USG is operator dependent and painful in presence of fracture.

MRI (Magnetic resonance Imaging) is preferred mode of investigation as it visualizes soft tissues and bones in all planes
without any manipulation of elbow and no exposure to ionizing radiation. Only limiting factor is that it is not available at all centres and is expensive. Ideally should be performed after the meal when the baby is fast asleep. Anesthesia is rarely required.
Arthrography is an invasive procedure with exposure to ionizing radiation and carries risk of infection and usually performed during defi nitive treatment to demonstrate the injury and is no longer practiced as MRI and Ultrasonography are safer mode of investigations.
TFDH even with delayed diagnosis conservative management has shown to have favorable outcome with any residual deformity correcting itself with growth even when anatomic relationship is not maintained initially possibly as in Salter Harris type 1 lesion the entire epiphyseal growth plate remains with epiphysis so damage to growth plate is not common [3,5,6] . Till date there is no consensus on optimal treatment for TFDH, if the displacement is mild, only casting   is performed. In other cases, to achieve anatomically aligned closed reduction, percutaneous pinning or open reduction and fi xation are performed [7][8][9][10][11]. Early diagnosis is important to allow reduction of the fracture by closed manipulation. Many authors recommend avoiding late manipulation after 4-7 days) owing to concerns about avascular necrosis, trauma to the growth plate, and disturbance of growth [11]. Some authors prefer intraoperative arthrography for these patients because of the diffi culty in visualizing the distal humeral anatomy in very young children [1,4], for obtaining good alignment of fracture and stability in such cases [12].
Limitation of range of movements , cubitus varus and rarely cubitus valgus as have been reported as long term complication associated with TFDH [1][2][3]. which can be treated in later childhood by osteotomies if required.

Conclusion
TFDH is a rare injury which can be easily missed as it is