We have investigated whether the pattern of subchondral acetabular cyst formation reflects hip pathology and may provide a prognostic indicator for treatment. A single surgeon series of sequential hip arthroscopies was reviewed to identify the most recent 200 cases undertaken on a previously un-operated joint with pre-operative plain radiographs and computed tomography or magnetic resonance scan available for review. Also, serial “non-arthritic hip scores” (NAHS) recorded pre-operatively, at 6 weeks and 3 months post-surgery. The