A child with acute myeloid leukemia complicated by calcaneal osteomyelitis due to Mycobacterium abscessus infection after induction chemotherapy successfully salvaged with bedaquiline and clofazimine.

Our patient was a 4-year-old female with acute myeloid leukemia complicated with right calcaneal osteomyelitis due to Mycobacterium abscessus with subcutaneous abscesses extending to the popliteal and groin regions after two courses of induction chemotherapy according to NOPHO-AML 2012 protocol. She required multiple operations and prolonged anti-mycobacterial therapy. A high index of suspicion for mycobacterial infection is required for immunocompromised patients with prolonged fever or unusual presentation. Mycobacterial osteomyelitis is rare, difficult to diagnose and treat, and may necessitate prolonged interruption of anti-leukemic therapy. Multidisciplinary collaboration in patient management is crucial. Long-term toxicity of antimicrobials with uncertain efficacy should not be overlooked.

Vascularised bone graft is an effective technique for extracortical bone bridging to combat cemented megaprosthesis loosening at the bone-implant junction.

INTRODUCTION: The bone-implant junction is a potential site for aseptic loosening. Extracortical bone bridging at the bone-implant junction is advocated to improve implant fixation by forming a biological seal. We propose a novel technique with vascularised bone graft (VBG) to form an extracortical bone bridge at the bone-implant junction to enhance implant stability. We compared the clinical and radiological outcomes for tumour megaprostheses performed (1) with and without bone graft and (2) with non-vascularised versus VBG technique. METHODS: Forty-six tumour megaprosthesis procedures from 1 June 2007 to 31 October 2017 were identified from hospital records. Twenty-eight operations incorporated bone graft at the bone-implant junction, and 18 did not. Of these 28 bone graft procedures, 13 involved VBG, and 15 did not (non-VBG). The VBG technique involves resecting a short segment of healthy bone beyond the oncological margin with its preserved blood supply, splitting it, then securing it over the junction. Clinical outcomes assessed included loosening, fracture and recurrence. Extracortical bone growth at the bone-implant junction was quantified radiologically at intervals 0-24 months post-operatively. The mean follow-up was 4.27 years. RESULTS: There were five incidences (27.8%) of loosening in the non-bone graft group compared to zero in the bone graft group (p = 0.03). There was a higher radiological score of extracortical bone growth in the bone graft group compared to no bone graft at 3-24 months post-operatively (p < 0.05). Within the bone graft group, the VBG group fared superior at 6 and 12 months post-operatively compared to non-VBG (p < 0.05), as well as a lower rate of radiological junctional resorption (p = 0.04). CONCLUSIONS: We recommend bone grafting for its merits of less implant loosening. We propose the VBG technique to combat early aseptic loosening in megaprosthesis replacement as there was a higher radiological score compared to non-VBG.

Giant cell tumor of the humeral head treated by denosumab: Implication to shoulder surgeons.

Giant cell tumor is a benign bone tumor that is commonly encountered. The optimal treatment of a giant cell tumor which causes extensive bony destruction is controversial. Recent studies on the receptor activator of nuclear factor κB ligand antagonist denosumab may offer a new treatment option for these patients. We presented a patient with giant cell tumor of the humeral head. He was initially treated with denosumab and subsequently with the operation. The shoulder joint was successfully salvaged. But there are potential difficulties that surgeons may face in patients treated with denosumab.

Unusual presentations of osteoarticular tuberculosis in two paediatric patients.

Tuberculosis is a universal mimicker and thus could be a differential diagnosis of any osteolytic lesion. Bone biopsy is crucial in these cases for culture and histological proof of tuberculous infection. This is a case report of two paediatric patients with unusual presentations of tuberculosis. One patient presented with knee pain and had imaged findings of an osteolytic lesion at the epiphysis. Interval scan showed spread of the lesion through the physis to the metaphyseal region. The second patient presented with hip pain and an osteolytic lesion of the acetabulum. He was subsequently found to have involvement of the brain and spine as well. Both patients were diagnosed with tuberculosis by bone biopsy for culture and pathological examination. They were treated successfully with antituberculous medications without chronic sequelae. These two patients showed that early recognition and prompt treatment are critical for management of tuberculosis to avoid chronic sequelae.