Alkaptonuria is a hereditary disorder of homogentisic acid metabolism. It is usually inherited in an autosomal recessive manner, although there have been reports of autosomal dominant inheritance1. In alkaptonuria, a defect in the gene that encodes homogentisic acid oxidase leads to an accumulation of homogentisic acid in the body1-4. This leads to the polymerization of homogentisic acid, which is exhibited as blue-black discoloration of various connective tissues, including hyaline cartilage. The prevalence of alkaptonuria is between one in 250,000 and one in one million people. A prevalence as high as one in 19,000 has been found in people of Slovenian and Dominican descent1,4-6. The disease is typically asymptomatic until the third or fourth decade of life. Clinically, it manifests as dark pigmented urine, abnormal pigmentation of the eyes and the ears, spondylosis, and degenerative arthritis throughout the body1-4. The orthopaedic manifestation of this disease is termed “ochronosis.” Ochronosis is a noninflammatory degenerative arthritis that results from the accumulation of homogentisic acid deposits in the joints. The knees, hips, shoulders, and spine are the most commonly affected areas1-4. Histopathologically, brown-black pigmentation occurs in the extracellular matrix of hyaline cartilage. In osteoarthritis, the hyaline cartilage appears as concentric layers of fibrillation; in ochronosis, the hyaline cartilage becomes fragmented with deep clefts that propagate toward the subchondral bone6. There is no known direct association between ochronosis and femoral neck stress fractures. To our knowledge, there has been only indirect mention of a femoral neck stress fracture in a single case report in the anesthesiology literature7. We present a case of an insufficiency femoral neck stress fracture in a patient with previously undiagnosed asymptomatic ochronosis. The patient was informed that …