Treatment for Periprosthetic Cyst after Total Hip Arthroplasty: Analysis of Six Cases

The present study investigates the pathogenesis of periprosthetic cysts after total hip replacement, and explores appropriate treatment appoaches. Six patients with periprosthetic cysts after total hip arthroplasty were treated at the First Affiliated Hospital of Nanjing Medical University between 2009 and 2014. During surgery, it was found that all cysts communicated with the hip and the hip prosthesis could be seen after cyst excision. Four patients simply underwent cyst excision, and light red liquid was found in the cyst. Among them, radiological examination revealed that a part of the hip prosthesis projected from the bone bed in one case. Postoperative pathology revealed a synovial cyst with inflammatory cell infiltration. Prostheses were loosened in two cases, so cystectomy and revision of the prosthesis were performed at the same time. Among the six patients, polyethylene wear particles could be seen in five patients through a pathological polarizing microscope. Out of the four patients who underwent simple cyst excision, two patients experienced cyst recurrence within 1 year after surgery; however, there was no cyst recurrence in the two patients who underwent cyst excision and revision of the prosthesis. The formation of a periprosthetic cyst after hip replacement is likely to be related to polyethylene wear and undesirable prosthesis position; in addition, when treated by simple cyst excision, the rate of recurrence was higher.