Cases of the Entrapment Neuropathy of the Common Peroneal Nerve Misdiagnosed as the Lumbar and Knee Disorders.

41 limbs in 34 patients with entrapment neuropathy of the common peroneal nerve were operated on in our department. Among these, 11 limbs in 7 cases were diagnosed as having osteoarthritis, and 11 limbs in 11 case as lumbar disc herniation before our diagnosis.The causes of these misdiagnoses were investigated with medical care records.The causes of misdiagnoses as lumbar disc herniations were as follows: paresthesia from the lateral aspect of the leg to the dorsal aspect of the foot as the patient complaint, misunderstanding of the symptoms from the extension and compression of the common peroneal nerve as a positive SLRT (straight leg raising test), relying on image studies without precise examination of the physical findings, and no consideration of the entrapment neuropathy as a differential diagnosis.The causes of misdiagnoses as knee joint disorders were as follows: gonalgia as the patient complaint, diagnosis relying on image studies without precise examination of the physical findings, and no consideration of the entrapment neuropathy as a differential diagnosis.In the diagnosis of lumbar spinal and knee joint disorders, the entrapment neuropathy of the common peroneal nerve should be considered as a differential diagnosis.