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A pain in the knee

19 July 2018
Miss F, an overweight 11-year-old, attended her GP, Dr A, complaining of knee pain and clicking for two months following a twisting injury whilst playing football. 

Examination was unremarkable, with straight-leg raising to 90 degrees and a full range of movement in the knee. Dr A treated with simple analgesia and arranged for an x-ray of the knee the following week. The x-ray was normal and Miss F was advised to see her GP for review.

Miss F next attended the practice seven weeks later, when she was seen by Dr B. She was complaining of pain in the right groin, which was worse on walking or standing. Dr B recorded in her notes that it was “probably muscle strain or too much pressure on hip joint because of her weight”. She prescribed diclofenac.

Five days later, Miss F attended the emergency department (ED) at the local hospital complaining of a painful right hip with difficulty walking. A diagnosis of ligament sprain was made.

Two days later, Miss F again attended the practice and was seen by Dr C. Examination revealed reduced range of movement in the right hip. Dr C arranged a routine appointment for a hip x-ray for the following week. 

The day before the appointment, Miss F attended the ED in severe pain. Hip movements, particularly flexion and internal rotation, were noted to be limited. The diagnosis of slipped femoral capital epiphysis was confirmed on x-ray and classified as “mild” (less than 30 degrees). Miss F subsequently underwent pinning of the epiphysis. 

Over the course of the next few years, Miss F attended her GP and the hospital on multiple occasions, complaining of intermittent hip pain. Her weight continued to rise and at age 15 her BMI was 41.4. MRI of the hip three years later showed deformity of the right hip with a CAM abnormality (bony deformity of femoral head resulting in femoro-acetabular impingement) and degenerative changes. The features were reported as being consistent with an angle of displacement of 50 degrees (severe slippage).

A claim was brought against Dr A alone, alleging a failure to recognise or appreciate that pain in the knee could be referred pain from the hip, failure to examine the hip and failure to refer for x-ray of the hip. It was additionally alleged that, because of Dr A’s failures, Miss F suffered premature osteoarthritis and was likely to require a primary hip replacement in her late 30s, and two further revisions in her lifetime.

Expert opinion
Medical Protection sought opinion from a GP expert. The expert was critical of Dr A, stating that a reasonably competent general practitioner would know that a slipped upper femoral capital epiphysis is more common in adolescents who are overweight. He also opined that a reasonably competent GP being presented with an overweight adolescent complaining of knee pain should have been aware that this may have been referred pain from the hip. In these circumstances the GP should have carried out an examination of the hip and, if any abnormality had been found, should have considered the possibility of slipped upper femoral capital epiphysis and referred the claimant for an x-ray.

The expert said that there was also a failure by Dr A, and subsequently Dr B, to consider the diagnosis and to carry out an appropriate examination of the hip. For the same reason, the expert was also critical of the care provided by the ED doctors and of Dr C for failing to make an urgent referral to hospital the same day.

Based on the critical expert opinion, the case was deemed indefensible and was settled on behalf of Dr A for a moderate sum, with a contribution from Dr B and the hospital.

Learning points
  • SUFE is more common in obese adolescents (particularly boys) and may present following an acute, minor injury.
  • Pain may be poorly localised. Pathology in the hip can present as referred pain to the knee; hence a full assessment of the joints on either side of the affected joint should be undertaken.
  • There may be an associated limp with out-toeing of the affected limb.
  • Diagnosis is confirmed on x-ray, which may require a “frog lateral” view for confirmation.