Lump behind the knee

The patient, a 60-year old woman who had previously been fit and well, consulted a GP MDU member for a second opinion on a lump behind her right knee, which her own GP thought was a Baker's cyst.

The MDU GP found that the lump was a fluctuant swelling, approximately 8cm in diameter, in the lower part of the right popliteal fossa. He reconfirmed to the patient that it was a Baker's cyst. No further investigation or treatment was advised.

Six months later, the lump became more painful. The patient went back to see the MDU GP who requested an ultrasound scan. This was abnormal. An MRI scan confirmed a sarcoma behind the right knee. Despite chemotherapy, the mass did not shrink and the patient underwent above-knee amputation of her right leg.

A claim was received against the GP member alleging that he had failed to appreciate that the swelling might be cancerous and that he should have referred the patient to a specialist cancer treatment centre for investigation. It was also alleged that the delay in referral resulted in an unnecessary amputation.

The MDU obtained an independent GP expert report on breach of duty. The expert stated that the GP had failed to note that the swelling did not get smaller as the patient bent her knee. At 8cm, the lesion fell within NICE cancer guideline CG27 (1.13.7) which states that a soft tissue lesion greater than 5cm diameter and increasing in size is suggestive of malignancy and requires further investigation. The lesion was also in the lower part of the popliteal fossa, whereas a Baker's cyst usually develops in the space behind the hinged joint of the knee. The expert concluded that, due to the size of the swelling and its position, a routine ultrasound scan should have been arranged at the first consultation. However, he did not believe that it was mandatory to have referred the patient to a specialist cancer centre on this date.


The expert stated that the GP had failed to note that the swelling did not get smaller as the patient bent her knee.


A report on causation and condition and prognosis from an orthopaedic tumour specialist stated that because the tumour was poorly responsive to chemotherapy and was increasing in size in a very difficult area (between the two heads of gastrocnemius and around the soleus and very close to the neurovascular bundle), an amputation was always likely to have been required in any event.

Liability for failure to arrange an ultrasound was admitted. However, the case was defended on issues of causation – that is, that it was likely on the balance of probabilities that the patient would have required an amputation.

The orthopaedic surgical experts from both sides met and produced a joint statement agreeing that it was likely that amputation would have been avoided by an earlier referral but it was difficult to say at what point that opportunity had been lost.

After this meeting MDU lawyers advised that it was likely that a court would find that further investigation would have revealed the presence of a malignancy and that surgery at that stage would, on the balance of probabilities, have been by way of resection only and not amputation. It was therefore decided to settle the claim and a payment of over £200,000 for damages was agreed plus £84,000 for the claimant's legal costs.

Patricia Cassidy
Claims handler

This page was correct at publication on 04/12/2013. Any guidance is intended as general guidance for members only. If you are a member and need specific advice relating to your own circumstances, please contact one of our advisers.


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