Stiff person syndrome: a rare cause of bilateral femoral neck fractures and fixation failure

<h3></h3> A 42-year-old lady with type 1 diabetes mellitus and hypothyroidism developed difficulty with gait initiation, lower limb stiffness and spasms. After six months, she sustained a left femoral neck fracture resulting from a muscle spasm and low impact fall. Dynamic hip screw was complicated by increased stiffness and muscle spasm, and was ultimately removed due to facture nonunion. Diazepam, baclofen and pregabalin were commenced with partial response. Eighteen months later she experienced a spasm resulting in right femoral neck fracture while transferring into her wheelchair. She underwent successful hemiarthroplasty and was referred to neurology. Severe lower limb and lumbar rigidity was noted with hyperreflexia and hyperekplexia. Stiff person syndrome (SPS) was confirmed by electromyography, demonstrating co-contraction of agonist and antagonist muscles in the lower limb and paraspinal muscles, and by positive antibodies to glutamic acid decarboxylase (GAD, titre &gt;2000U/ml). Diazepam was increased and 4-weekly intravenous immunoglobulin infusions commenced. After four cycles, 10-metre timed walk improved from 84 to 37 seconds, and there was marked improvement in the severity and frequency of spasms. Spasms associated with SPS are a rare cause of pathological fractures and may cause orthopaedic fixation to fail. Early recognition is important to prevent morbidity.