Endgames Picture Quiz

“It’s just a muscle sprain”

BMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f2503 (Published 30 April 2013) Cite this as: BMJ 2013;346:f2503
  1. Rej Bhumbra, locum consultant orthopaedic surgeon,
  2. William Aston, consultant orthopaedic surgeon ,
  3. Rob Pollock, consultant orthopaedic surgeon
  1. 1London Sarcoma Service, Royal National Orthopaedic Hospital, Stanmore, Middlesex, UK
  1. Correspondence to: R Bhumbra bhumbra{at}hotmail.com

A 10 year old boy presented to his general practitioner with a four week history of left mid-thigh pain with no associated history of systemic symptoms. He had no memory of a preceding trauma and no history of infection, locally or systemically. The pain was relapsing and remitting in its extent and frequency. It was also activity related, with occasional night waking and pain at rest. His GP took a full history, conducted a complete hip examination, and at initial presentation decided that the pain was caused by a muscle sprain.

Two months later the pain has not abated and the child re-presented to his GP, who requested a plain radiograph of the hip, the results of which were normal. A further three months later, his father noticed an associated distal thigh mass and immediately took the boy to the emergency department. On presentation to hospital, he was walking pain free but had an obvious mass, which did not limit his range of movement.

He did not have a fever; his C reactive protein was 6 mg/L, erythrocyte sedimentation rate was 4 mm in the first hour, and total white blood cell count was 8×109/L. The on-call orthopaedic team requested anterioposterior and lateral radiographs of the thigh (figs 1 and 2).

Figure1

Fig 1 Anterioposterior radiograph of the distal femur

Figure2

Fig 2 Lateral radiograph, midshaft femur

Questions

  • 1 Are there any red flag symptoms in the initial presenting history?

  • 2 Given this history, what other examination findings would be relevant?

  • 3 Would femoral radiography and its related radiation exposure have been warranted at an earlier stage?

  • 4 What do the anterioposterior and lateral radiographs taken six months after the onset of pain show?

  • 5 What would be the next stage in this boy’s management?

Answers

1 Are there any red flag symptoms in the initial presenting history?

Short answer

The four week history of intermittent pain with night symptoms in the absence of a history of trauma is worrying.

Long answer

Hip, thigh, and knee pain have many common and not so common causes, including congenital disorders (late developmental dysplasia of the hip), trauma (physeal injury, malunion), infection, neuromuscular disorders (polio, cerebral palsy), as well as bone and soft tissue tumours. A history of trauma can be misleading and cause delay in investigating further. The intermittent nature of symptoms in the presentation of primary bone sarcoma can also cause diagnostic difficulty.1

The initial red flag symptoms in this presentation are the relapsing and remitting nature of the pain, the associated pain at night, the lack of improvement over time, and lack of a definite history of trauma. Other red flag symptoms include systemic symptoms, a reported or palpable mass, low energy bony injuries, unexplained bone or deep limb pain, or symptoms that persist for more than four weeks without a confirmed diagnosis.

2 Given this history, what other examination findings would be relevant?

Short answer

Examination of the spine and knee is useful to exclude more proximal and distal disease, respectively. The presence or absence of a mass, joint effusion, swelling, and skin rashes can also help in the diagnosis.

Long answer

Slipped upper femoral epiphyses can present with knee pain, as can developmental hip dysplastic disorders with late presentation. Conversely, knee disease can present with hip pain. This is because the femoral nerve provides sensory function to the hip joint capsule and the knee. In addition, disease of the lumbar spine can produce radicular symptoms, which can present with pain in the lower leg, knee, or hip. Clinical examination of the hip, specifically pain and abnormalities in range of movement, is important to determine an appropriate differential diagnosis.

Temperature can help in the diagnosis of an inflammatory or infective disease. Septic arthritis usually causes a marked reduction in range of joint movement, whereas osteomyelitis may have little impact on the joint. Inflammatory diseases such as the vasculitides may present as arthralgia, along with the presence of skin rashes and sometimes abdominal pain. Reactive synovitis after infection can also present with joint or limb pain.

3 Would femoral radiography and its related radiation exposure have been warranted at an earlier stage?

Short answer

Yes. An initial radiograph is important to exclude sinister causes of pain, and radiography of the extremities exposes patients to relatively little radiation. Modern radiation machines expose patients to less than 1.5 days of background radiation on imaging of the extremities,2 so femoral radiography is a safe, inexpensive, and vital way to excluding serious disease.

Long answer

Obtaining the definitive diagnosis is not the absolute priority, but safe management to prevent missing something rare but serious is mandatory. Modern plain radiography of the extremities involves minimal radiation exposure. In a child with limb pain of more than four weeks’ duration that has no definitive explanation, the traditional medical school mantra of history and examination should be modified to history, examination, and radiography. The diagnosis of unilateral growing pains should not exist. This may be the only way to reduce the time to referral for appropriate treatment, which has not improved over the past 25 years.3

4 What do the anterioposterior and lateral radiographs taken six months after the onset of pain show?

Short answer

A mixed lytic and blastic aggressive tumour within and extending out from the distal diaphysis of the femur, with an associated soft tissue mass and distal mineralised skip lesion (figs 3 and 4).

Figure3

Fig 3 Anterioposterior radiograph of the distal femur showing new expansile bone formation (white arrow) with overlying soft tissue mass; periosteal reaction, with the deposition of Codman’s triangles between the undersurface of the periosteum and outer host bony cortex (black arrow); indistinct lesional border, with a wide zone of transition; and a distal “skip” lesion (double white arrowhead)

Figure4

Fig 4 Lateral radiograph of the midshaft femur showing new expansile bone formation (white arrow) with overlying soft tissue mass; periosteal reaction, with the deposition of Codman’s triangles between the undersurface of the periosteum and outer host bony cortex (black arrow); indistinct lesional border, with a wide zone of transition; and a distal “skip” lesion (double white arrowhead)

Long answer

Radiographic assessment is unable to confirm the presence of a malignant or benign lesion, but it can help assess whether a disease process is likely to be aggressive or non-aggressive. If a bone tumour has not caused bone changes visible on a radiograph it may be missed, which makes serial imaging, or alternative modalities such as magnetic resonance imaging, invaluable in early detection.

Specific aggressive features on this radiograph are new expansile bone formation; soft tissue mass; periosteal reaction, with the deposition of Codman’s triangles between the undersurface of the periosteum and outer host bony cortex; indistinct lesional border, with a wide zone of transition; and a distal “skip” lesion.

“Safety netting” is about producing practical methods that reduce the chances of dangerous causes or disease being missed. Requesting a plain radiograph, which is then reported by an appropriately qualified musculoskeletal radiologist is one of those safety mechanisms. The report finding should be faxed and telephoned through a direct two way conversation with the referrer, whether a GP or hospital team.

5 What would be the next stage in this boy’s management?

Short answer

Urgent referral to a supraregional bone sarcoma unit, with subsequent prompt and local magnetic resonance imaging of the lesion and entire bone.

Long answer

Magnetic resonance imaging to determine the extent of bone and soft tissue involvement is used to plan the biopsy route. If performed urgently and locally, time can be saved, as can a potentially unnecessary long journey to the supraregional centre for the subsequent biopsy. The biopsy is performed in the specialist centre because the biopsy tract is resected en bloc with the tumour. Knowledge of the planned resection approach requires the operating surgeon’s input at the biopsy planning stage and is marked on the pre-biopsy imaging.

Bone sarcoma is rare, with an incidence of about 1 per 100 000 population,4 so differentiating between these lesions and the more common benign ones requires expertise. Once the diagnostic triad of histopathology, imaging, and clinical assessment are complete, the diagnosis of osteosarcoma can be made. This is followed by full staging with a bone scan and computed tomogram of the chest. Computed tomography exposes the child to higher radiation levels and should be performed only in the setting of a known sarcoma. Indeed, computed tomography accounts for 9% of all radiological examinations but 47% of medical radiation doses.2

Obtaining a diagnosis of osteosarcoma and delivering appropriate treatment mandates the involvement of a multidisciplinary team, including oncologists, radiologists, pathologists, clinical nurse specialists, and orthopaedic surgeons trained in oncology. In 2006, the National Institute for Health and Care (formerly Clinical) Excellence advised that patients with suspected bone tumours should be referred to one of five supraregional centres that deal with these tumours (London, Birmingham, Oxford, Newcastle, and Oswestry).5

In summary, any patient with limb pain, particularly intermittent non-mechanical pain, should be referred for radiography. The presence of bone lysis, new bone formation, periosteal elevation, or soft tissue swelling should lead to further investigation and referral.6 Obviously this crucial radiographic information is not available if the radiograph is not requested in the first place.

Patient outcome

After the diagnosis of osteosarcoma the patient underwent chemotherapy and limb salvage surgery with a margin negative resection. He had a greater than 90% necrosis response to chemotherapy and endoprosthetic joint reconstruction was carried out using a non-invasive growing prosthesis. He remains disease free four years later.

Notes

Cite this as: BMJ 2013;346:f2503

Footnotes

  • Competing interests: I/we have read and understood the BMJ Group policy on declaration of interests and declare the following interests: None.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Patient consent obtained.

References