Lateral Condyle Fracture
Lateral condyle fractures account for 16%  of elbow injuries in children. They have been shown in a cadaveric study to be due a fall onto an extended and supinated arm, resulting in an avulsion injury from the common extensor and lateral ligamentous attachments2.
There are multiple classifications for these injuries. Our preferred is the Song  classification as it can help guide treatment. Song et al  described a system based upon fracture extension into the joint surface and associated displacement. Graded 1 to 5, it has been recently validated by Ramo et al . Grades 1 and 2 have an intact cartilaginous hinge and are extraarticular in nature. Grades 3 and 4 are intraarticular varying levels of displacement. Grade 5 demonstrates gross rotation of the fragment.
3 radiographic views are required – AP, lateral and internal oblique. This avoids any subtle fractures being missed and allows assessment of extension/displacement. Some authors also advocate a 20 degree AP view as the fracture has been consistently proven to be, on average, 21 degrees to a line perpendicular to the anatomical axis in the sagittal view . If there is doubt as to the extent of the fracture line this needs to be further evaluated with an arthrogram.
For Song grades 1 and 2 a trial of non-operative management, via the use of an above elbow POP can be attempted. The child requires weekly radiographs, out of cast, to ensure there is no change in position. The worst outcomes for these injuries come from poorly managed non operated cases.
For grades 3 and 4, which are intraarticular in nature, an arthrogram under GA is performed. Closed reduction and percutaneous pinning can be attempted but anatomical reduction of the joint surface is required (as assessed by the arthrogram). Two divergent 2mm kwires can then be used for fixation before the elbow is placed into an above elbow POP. Wires are removed at 4 weeks prior to cast immobilisation for a total of 6 weeks. If the articular surface cannot be reduced via closed methods the injury is treated via an open reduction.
Screw fixation, as opposed to k wires, has been discussed in the literature but there a no long term outcomes to assess the efficacy.
Grade 5 injuries require open reduction prior to fixation. The lateral Kocher approach is used to gain visualisation of the joint surface. Care is taken to avoid posterior soft tissue stripping which can disrupt the lateral condyle blood supply. The treating surgeon is also mindful of the PIN in the distal extent of the incision. Once exposed, a dental mirror can be a useful aid to visualise the medial extent of the articular surface. Following anatomical reduction under direct vision k wire fixation is performed in the same manner as that of a grade 3-4 injury.
A study  from this unit has demonstrated a high (23%) rate of skin erosion with buried wires, hence wires are left proud where possible. This also facilitates removal in the outpatient department and avoids a further trip to theatre.
Outcomes are generally good in appropriately treated patients. 90% of the range of movement arc, when compared to the uninjured side, is recovered by 24 weeks . Simple pin site infections are treated via oral antibiotics. Non union is rare (0.9%1) and most likely in patients treated non operatively inappropriately. Varus malalignment is more common (9.7%8) than cubitus valgus. The latter can be associated with a growth arrest and tardy ulna palsy. Both deformities can be treated via corrective osteotomies. Lateral spurring is associated with operative intervention, often without functional deficit. Fishtail deformity, a central osseous defect between ossification centres, also leads to minimal functional deficit but should be followed up. AVN can be avoided with minimal posterior soft tissue stripping.
1 - Stevenson RA, Perry DC, Paediatric lateral condyle fractures of the distal humerus, Orthopaedics and Trauma (2018)
2 - Jakob R, Fowles JV, Rang M, Kassab MT. Observations concerning fractures of the lateral humeral condyle in children. J Bone Jt Surg Br 1975; 57: 430e6.
3 - Song KS, Kang CH, Min BW, et al. Closed reduction and internal fixation of displaced unstable lateral condylar fractures of the humerus in children. J Bone Joint Surg Am. 2008;90:2673–2681.
4 - Ramo BA, Funk SS, Elliott ME, Jo CH. The Song Classification Is Reliable and Guides Prognosis and Treatment for Pediatric Lateral Condyle Fractures: An Independent Validation Study With Treatment Algorithm. J Pediatr Orthop. 2020 Mar;40(3):e203-e209.
5 - Imada H, Tanaka R, Itoh Y, Kishi K. Twenty-degree-tilt radiography for evaluation of lateral humeral condylar fracture in children. Skeletal Radiol 2010; 39: 267e72.
6 - Ormsby NM, Walton RD, Robinson S, Brookes-Fazakerly S, Chang FY, McGonagle L, Wright D. Buried versus unburied Kirschner wires in the management of paediatric lateral condyle elbow fractures: a comparative study from a tertiary centre. J Pediatr Orthop B. 2016 Jan;25(1):69-73.
7 - Bernthal NM, Hoshino CM, Dichter D, Wong M, Silva M. Recovery of elbow motion following pediatric lateral condylar fractures of the humerus. J Bone Jt Surg Am 2011; 93: 871e7.