The Outcomes of Bone Grafting of Peri-Prosthetic Total Ankle Osteolytic Lesions: A Meta-Analysis

CATEGORY: Ankle INTRODUCTION/PURPOSE: Total ankle replacement (TAR) has become an increasingly popular alternative to ankle arthrodesis as a treatment option for end-stage ankle arthritis. However, total ankle implants are not without short and long-term complications and one of the most common is peri-prosthetic osteolysis, Many studies have been done on the incidence of peri-prosthetic bone cysts as well as the etiology, but there have been limited reports on the optimal management of these lesions. The most widely accepted method of treatment is curettage and grafting of the lesion with or without polyethylene exchange. Our aim was to perform a systematic review of the literature on the outcome of bone grafting in the management of periprosthetic osteolytic following TAR. METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, Medline, PubMed, Scopus, and Google Scholar databases were searched in November and December 2018 for all observational or experimental studies that evaluated bone grafting of peri-prosthethic total ankle osteolytic cysts. The primary outcome was the rate of major revision to either component replacement or ankle arthrodesis and the secondary outcome was the rate of radiological cyst progression after grafting. Descriptive, quantitative, and qualitative data were extracted. RESULTS: Of the 70 articles identified, 6 studies were eligible for the meta-analysis for a total of 120 patients with 123 total ankle replacements. Average age of subjects was 58.5 years. 4 papers included details of patient gender revealing 50 males and 26 females in those studies. The most common type of total ankle replacement was the Ankle Evolutive System(AES) followed by the Scandinavian total ankle replacement (STAR). With an average follow up 5.1 years (1.4-15.4), the rate of conversion to major revision after curettage and bone grafting was 15% (7.6%- 22.4%). Despite that apparent success, there was a 40.4% (5.4%-75.4%) rate of radiological cyst progression after grafting CONCLUSION: Our systematic review shows that curettage and bone grafting of the osteolytic lesions around TAR is safe procedure which can increase the survivorship of the implant and delay the need for further major surgeries. Providing better bone stock for later revision may also be of benefit. However, the high rate of cyst progression is worrisome for future complications. This highlights the need to further research the etiology of the cyst and to explore treatments aimed at eliminating the cause of cysts to prevent the need for repeat procedures and the potential for implant failure.