Knee dislocation of a morbidly obese patient: a case report

Knee dislocations of morbidly obese patients after a trivial fall are not uncommon. We report a case of closed reduction for a dislocated right knee of a 26-year-old obese woman. After closed reduction under general anaesthesia, her knee was supported by pillows in 30 degrees flexion. No external splint was used because of the enormous size of the leg. At day 4 after reduction, the patient had numbness over the dorsum of the right foot and was unable to dorsiflex. She was diagnosed as having peroneal nerve palsy and was fitted with a foot drop splint. One week after reduction, she started active, assisted knee mobilisation and tip-toe weight bearing. At 24 months after reduction, the patient was able to walk unaided and had 100 degrees of knee flexion. She had a good foot function and a grade II in the Lachman's test, with no varus or valgus instability. This case highlights the importance of early mobilisation, which can result in good outcome even without operative treatment.