A case of pathological fracture caused by vitamin D insufficiency in a young athlete and a review of the literature.

Our patient is a 16-year-old boy basketballer with no significant medical history or previous injuries. He fell on his right hip during jogging and sustained a right superior-posterior hip dislocation with a Pipkin type 2 fracture of the femoral head. Manipulation and reduction under sedation then general anaesthesia was unsuccessful he underwent open reduction and internal fixation. Because his fall was of low energy, an endocrinologist was consulted to rule out primary contributing factors to his fracture dislocation. He was found to have insufficient levels of vitamin D (22.4 μg/l) which was replaced subsequently. Other hormonal investigations were unremarkable. The Bone Mineral Density of his left femoral neck measured 1.098, corresponding to a Z-score of 1.1 (normal). At 2 months post operation, our patient was pain free and able to ambulate without aid. Follow up Xrays showed satisfactory alignment with no evidence of osteonecrosis. We conducted a literature search on pubmed with keywords: Hip, dislocation, fracture, minimal trauma, atraumatic, vitamin D deficiency. We then excluded post-operative dislocations and found 4 articles reporting minimal or atraumatic hip dislocations. Posterior hip dislocations have been reported in literature to be a high energy trauma, usually due to an axial load on the femur, typically with hip flexed and adducted. Complex posterior fracture-dislocation of the native hip joint in adults is usually caused by road traffic accidents or falls from heights. Native hip dislocations in adults associated with minimal or no trauma are rarely reported in literature, and are mostly due to hip dysplasia, arthritis, connective tissue disorders or spastic muscular paralysis. Of note there are no reports of vitamin D deficiency causing a hip fracture dislocation. This is the first known case of an athlete sustaining a vitamin D insufficiency fracture. In patients presenting with posterior hip dislocations after minimal or no trauma, underlying causes must be excluded. More research is necessary to investigate the relationship between vitamin D insufficiency and hip dislocations.