Intra- and Periarticular Ganglia (Synovial Cysts) of the Hip with Compression of the Obturator Nerve, Concomitant with Lesions of the Ligamentum Teres—A Report of 3 Cases

Background: Synovial cysts of the hip are commonly found in patients with intra- or extraarticular pathologies of the joint. Symptoms are mostly unspecific. To date there are no guidelines for a gold standard of treatment. Aim of this article is to show up how lesions of the ligamentum teres (LT) might possibly lead to a specific formation of synovial cysts of the hip joint and how this can be treated arthroscopically. Methods: This case series included 3 patients with ganglia of the hip. All patients had impingement symptoms, combined with untypical location of pain. All patients qualified for joint preserving surgery and underwent hip arthroscopy with pre- and postoperative MRI imaging. The mean follow-up time was 22 months. Results: MRI imaging showed extensive ganglia, presumably originating from the pelvic root of LT, extending to the obturator lodge. In 2 of 3 cases MRI showed lesions of the LT. Hip arthroscopy revealed damage of the LT in all cases, caused by chronic instability of the joint. The postoperative MRI showed a complete regression of the ganglia in all patients after offset correction. After follow-up, 2 of 3 patients were mostly symptom free. One patient was still suffering from a chronic weakness of the gluteus medius muscle. Conclusion: Whenever unspecific radiating pain of surrounding areas of the hip is encountered and cannot be explained by common pathologies of the hip, possible compression of nerves by ganglion cysts should be excluded. This should be done by MRI arthrography. A partial rupture of the LT can occur during FAI with consecutive formation of ganglia in the obturator canal, compressing the obturator nerve. Primarily the articular pathology needs to be repaired. In our cases, this was feasible by hip arthroscopy, as a minimally invasive and safe technique.