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Trauma

Elbow “TRASH” (The Radiographic Appearance Seemed Harmless) Lesions

Waters, Peter M. MD; Beaty, James MD; Kasser, James MD

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Journal of Pediatric Orthopaedics: March 2010 - Volume 30 - Issue - p S77-S81
doi: 10.1097/BPO.0b013e3181c18a9f
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Abstract

Although the vagaries of the secondary centers of ossification can provide a diagnostic dilemma at times, radiographic assessment of most injuries around the pediatric elbow are relatively straightforward for the experienced pediatric orthopaedic surgeon. There are, however, a small subset injuries that can be missed and as a result, have dire consequences in the long term. Kasser has defined these injuries as “TRASH lesions” (Table 1): the radiographic appearance seemed harmless. These lesions are predominantly osteochondral injuries in children less than age 10 years of age,1–5 often associated with unrecognized, spontaneously reduced elbow dislocations. Small, anterior radial head compression fractures with initially subtle, then progressive, posterior radiocapitellar subluxation, are a classic example of this subgroup of serious injuries (Fig. 1). A high index of suspicion, early additional imaging [ultrasound, arthrogram, magnetic resonance imaging (MRI) scan],6 and aggressive surgical care are usually necessary for prompt diagnosis and successful treatment of these injuries before complications arise.

FIGURE 1.
FIGURE 1.:
A, Acute injury films revealing small displacement of radial head fracture on the flexed elbow anteroposterior (AP) view and subtle posterior subluxation not originally appreciated on the lateral view. B, Follow-up radiographs at 1 week noted more difficulty interpreting the AP view in cast, and more radiocapitellar posterior displacement on the lateral view. An MRI scan (C) was ordered urgently and revealed a marked effusion and intra-articular displacement of radial head fracture and posterior radiocapitellar subluxation. D, Open reduction internal fixation was performed to anatomically align the radial head fracture and reduce the joint.
TABLE 1
TABLE 1:
Elbow “TRASH” Lesions

HISTORY, EXAMINATION, AND RADIOGRAPHIC EVALUATION

The history is usually indicative of high-energy trauma. For example, a fall from a significant height in a small-sized child (Fig. 2).7 The examination generally reveals more swelling than expected by the misinterpreted benign radiographs. Flexion extension of the elbow and/or rotation of the forearm is often restricted. If inspected closely, the radiographs usually reveal a bony fragment or a joint malalignment. However, in a busy emergency room or office setting, without close, careful inspection, qualified physicians and surgeons have missed the findings. Due diligence is required to make the diagnosis acutely. Special imaging is usually necessary to define the extent of the injury and plan appropriate care. Ultrasound in a skilled pediatric center may be diagnostic with cartilaginous injuries and does not require sedation even in the young child (Fig. 2).7 MRI scans in the ambulatory setting will be diagnostic6 but may require conscious sedation (Figs. 3, 5) Intraoperative arthrograms can also be definitive (Fig. 4) but fracture dislocations may have leakage of dye into the surrounding soft tissues that can be confusing. In any given patient, some or all of this work-up may be necessary to reach clarity on diagnosis and care.

FIGURE 2.
FIGURE 2.:
A, Anteroposterior radiograph, made 4 weeks after the injury, showing a mild irregularity of the metaphyseal border (arrow) of the proximal aspect of the right radius. The radiographs that had been made at the time of the injury had been interpreted as normal. B, Coronal ultrasonographic image of the radiocapitellar joint, showing the radial metaphysis (arrows) to be contiguous with the distal humeral epiphysis. The radial head is not visualized. C=ossification center of the capitellum. C, Line drawing of the ultrasonographic image shown in Figure 1B, depicting separation of the proximal radial physis. The shaded area corresponds to cartilage, and the dotted lines indicate osseous contours obscured by shadowing. The unossified radial head is absent, and the capitellum abuts the radial metaphysis. 1=unossified capitellum, 2=ossification center of the capitellum, 3=radial metaphysis, and 4=fascial plane. D, Coronal ultrasonographic image of the unaffected, left elbow, showing the normal appearance of the cartilaginous radial epiphysis (arrow). E, Line drawing of the ultrasonographic image shown in Figure 1D. The ossification center of the capitellum is not shown. The shaded areas correspond to cartilage, and the dotted line indicates the osseous contour obscured by shadowing. 1=unossified capitellum (partially sectioned), 2=unossified radial head, 3=proximal aspect of the ulna, 4=fascial plane, and 5=radial metaphysis. F, sagittal fat-suppressed T2-weighted magnetic resonance image of the right radiocapitellar joint, showing the capitellum (C) to be articulating with the radial metaphysis, which has an irregular border (arrow). G, Coronal gradient-recalled-echo magnetic resonance image of the patient described in this study, showing an ovoid fragment of cartilage corresponding with the separated radial epiphysis (*), just distal to the capitellum (C).7
FIGURE 3.
FIGURE 3.:
Sagittal fat-suppressed T2-weighted magnetic resonance image of the radiocapitellar joint of a different patient, an 18-month-old boy who had a nondisplaced fracture of the distal humeral metaphysic (not shown), showing the normal appearance of the unossified structures of the elbow. The contour of the unossified capitellum (C) is outlined by the joint effusion. The radial head (arrow) has the same configuration as that of the radial head in an adult, even though it is completely unossified.
FIGURE 4.
FIGURE 4.:
A, Anteroposterior view of a distal humerus fracture. This is a medially displaced bony fragment. The patient had marked swelling and limitations of motion. A medial condylar fracture was suspected. B, Intraoperative arthrogram reveals marked intra-articular displacement that was treated with open reduction and pin fixation. This fracture is too often missed in the skeletally immature.

Specific injuries include (1) epiphyseal separations (Fig. 5); (2) displaced intra-articular medial condylar fractures before ossification of the secondary center (age 7 to 8 y) (Fig. 4); (3) capitellar shear fractures; (4) radial head fractures with radiocapitellar subluxation (Fig. 1); and (5) osteochondral fractures of the olecranon, radial head or distal humerus with joint incongruity (Fig. 6). With regard to the last 3, any elbow dislocation in a child less than 10 years old should raise concerns about a displaced, intra-articular osteochondral fracture. In retrospect, the diagnosis appears obvious. The challenge is in prospective, prompt diagnosis.

FIGURE 5.
FIGURE 5.:
A, Oblique anteroposterior and lateral views in a young child reveals some displacement that could have been accepted with a remodeling potential. B, magnetic resonance imaging reveals marked displacement that leads to operative reduction and fixation.
FIGURE 6.
FIGURE 6.:
A, Anteroposterior, lateral, and oblique views of an osteochondral fracture of the lateral condyle. If unrecognized, this can lead to painful nonunion and intra-articular incongruity. B, Magnetic resonance imaging (MRI) scan documenting displacement and operative indications. C, Percutaneous reduction and screw fixation was performed based on MRI findings.

TREATMENT

Displaced injuries require anatomic articular reduction. Most are unstable and require operative fixation. In cases with multiple fractures, preoperative planning, often with special imaging, is mandatory to determine the best surgical approach. Instrumentation of the fracture(s) has to be appropriate for fracture fragment size. The options include permanent 1.5 to 3.5 mm plates and/or screws, osseous screws or anchors,8 suture fixation of osteochondral flaps, and/or removable smooth, small wires. Rigid internal fixation is preferred to allow for early, protected motion. Soft tissue reconstruction may be necessary if there is still instability after operative fixation of the fracture(s). Repair of disrupted ligaments to the periosteum or with osseous suture anchors is performed in markedly unstable situations. With stable constructs, hinged elbow braces are used to gradually regain flexion—extension while avoiding varus—valgus stress. However, it may be necessary to immobilize in a long arm until sufficient bony healing if the fixation or vascularity of the fragments is precarious.

The most common complication with these rare injuries is failure to make an accurate diagnosis in a timely manner. Acute care is usually in a splint or cast for an inaccurate, simplified diagnosis of a contusion, sprain, or nondisplaced fracture. Referral for further consultation is often late when pain and limitations in motion and function persist. This may be after a trial of therapy. Unfortunately, anatomic reconstruction may not then be possible. Consequently, permanent malalignment, limited motion, and function may be the end result.

COMPLICATIONS

Unfortunately, even when the diagnosis is made acutely and surgical intervention is prompt, there can be a poor end result. Incomplete or unstable reduction of the fracture fragment(s) or joint has occurred. In cases with multiple fractures, one or more of the injuries has been missed and consequently, not treated surgically. Avascular necrosis, heterotopic ossification, periarticular contractures, and late joint subluxation all have developed with these injuries. Simply, care of these injuries is not for the uninitiated.

CONCLUSIONS

To reiterate, a high index of suspicion, early additional imaging (ultrasound, arthrogram, MRI scan), and aggressive surgical care are usually necessary for prompt diagnosis and successful treatment of these “TRASH” lesions before complications arise. These injuries are not to be simplified either in diagnosis or treatment.

REFERENCES

1. Sodl JF, Ricchetti ET, Huffman GR. Acute osteochondral shear fracture of the capitellum in a twelve-year-old patient. A case report. J Bone Joint Surg Am. 2008;90:629–633.
2. Keser S, Demirel N, Bayar A, et al. The coexistence of fractures of the capitellum and the radial head: a rare case. Acta Orthop Traumatol Turc. 2007;41:69–73.
3. Kajiwara R, Ishida O, Sunagawa T, et al. Osteochondral flap fracture of the olecranon in a child. J Pediatr Orthop. 2007;27:304–306.
4. Song KS, Jeon SH. Osteochondral flap fracture of the olecranon with dislocation of the elbow in a child: a case report. J Orthop Trauma. 2003;17:229–231.
5. Blamoutier A, Klaue K, Damsin JP, et al. Osteochondral fractures of the glenoid fossa of the ulna in children: review of four cases. J Pediatr Orthop. 1991;11:638–640.
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7. Lazar RD, Waters PM, Jaramillo D. The use of ultrasonography in the diagnosis of occult fracture of the radial neck. A case report. J Bone Joint Surg Am. 1998;80:1361–1364.
8. Silveri CP, Corso SJ, Roofeh J. Herbert screw fixation of a capitellum fracture. A case report and review. Clin Orthop Relat Res. 1994;300:123–126.
Keywords:

elbow; fracture; TRASH lesion; ostechondral injury

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