Humeral shaft hypertrophic non-union mimicking malignant lesion

Description

Isolated humeral shaft fractures account for 3–5% of adult fractures, and non-operative management is the mainstay of the treatment with overall good results. Humeral functional bracing is commonly used to provide mechanical stability aiding fracture healing.¹ However, non-union is a recognised complication of these fractures with an estimated prevalence of 5.5%.² Non-union occurs when a fracture has failed to heal in the expected time; hypertrophic non-union is associated with adequate healing response and good vascularity but lacks adequate immobilisation or stability to progress to union.^{2 3}

We present an interesting case of hypertrophic non-union of humeral shaft fracture in a 63-year-old woman. She is fully independent, medically fit and well, right-handed and a non-smoker presented to minor injuries unit with a painful left shoulder following a simple fall. On examination, she had mild tenderness over her acromioclavicular joint with a good range of motion in her shoulder and had an intact neurovascular status. However, while examining her arm, a completely asymptomatic mass was readily palpable over the middle left humerus with a detectable motion in the mid-humerus. On further questioning, it appeared that she was involved in a road traffic accident and sustained a closed humeral shaft fracture 17 years ago which was treated non-operatively.

Plain radiographs (figure 1) demonstrated a suspicious solitary diaphyseal humeral lesion, sparing the cortices and surrounding soft tissues with an abundance of bone formation. However, the diagnosis of hypertrophic non-union is confirmed on MRI (figure 2). She is fully functional and asymptomatic and no further management is required.

Figure 1.

Anteroposterior and lateral plain radiographs of left humerus demonstrating a hypertrophic non-union of humeral shaft fracture.

Figure 2.

Coronal and sagittal MRIs demonstrating hypertrophic non-union of humeral shaft fracture.

Learning points.

• When performing orthopaedic examination, always consider examining the joint above and below as appropriate.

• Humeral shaft fractures are common orthopaedic injuries that can often be managed non-operatively with high union rates and generally good functional outcomes.

• Radiological appearance of fracture non-union can mimic a malignant lesion, and if so further investigations are required.