Etiopathogenesis of osteolytic cysts associated with total ankle arthroplasty, a histological study.
BACKGROUND
Osteolytic cyst formation after total ankle arthroplasty has been identified in recent years and is probably an important problem with longer follow-up. The aim of this study is to describe the outcome of a histological analysis of samples from periprosthetic intra-osseous cysts and joint capsules, retrieved during revision surgery after primary total ankle arthroplasty.


METHODS
All samples (n=22) were analyzed and scored using a semi-quantitative grading system. The main items of interest were polyethylene (PE) particles, metal particles, histiocytes, and giant cells.


RESULTS
All cyst samples contained PE particles. A similar number of PE particles were found in talar and tibial cysts. No significant correlation between the number of PE particles and time to reoperation was found. Metal particles were found in 16 cysts.


CONCLUSIONS
We suggest that PE particles are not the primary cause of osteolytic cyst formation but a secondary contributing factor probably accelerating the process of osteolysis. It is likely that implant design, biomechanical factors and local anatomic-physiological factors play an important role.
Department of Orthopaedic Surgery, Slotervaart Hospital, Louwesweg 6, 1066 EC Amsterdam, The Netherlands.
Redmer
R
van Wijngaarden
Department of Orthopaedic Surgery, Slotervaart Hospital, Louwesweg 6, 1066 EC Amsterdam, The Netherlands.
Laurens
L
van der Plaat
Department of Orthopaedic Surgery, Slotervaart Hospital, Louwesweg 6, 1066 EC Amsterdam, The Netherlands.
Rebecca A
RA
Nieuwe Weme
Department of Orthopaedic Surgery, Slotervaart Hospital, Louwesweg 6, 1066 EC Amsterdam, The Netherlands.
H Cornelis
HC
Doets
Department of Pathology, Slotervaart Hospital, Louwesweg 6, 1066 EC Amsterdam, The Netherlands.
Johan
J
Westerga
Department of Orthopaedic Surgery, Slotervaart Hospital, Louwesweg 6, 1066 EC Amsterdam, The Netherlands. Electronic address: Daniel@drhaverkamp.com.
Daniel
D
Haverkamp
D000328:Adult; D000368:Aged; D058737:Arthroplasty, Replacement, Ankle / Q000009:adverse effects*; D001672:Biocompatible Materials; D003343:Corrosion; D003560:Cysts / Q000209:etiology / Q000473:pathology*; D005260:Female; D005549:Foreign-Body Reaction / Q000473:pathology; D006801:Humans; D017746:Joint Capsule / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000209:etiology / Q000473:pathology*; D020959:Polyethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D012189:Retrospective Studies; D013628:Talus / Q000473:pathology; D013977:Tibia / Q000473:pathology; D055815:Young Adult
D001672:Biocompatible Materials; D020959:Polyethylene
Ankle; Cysts; Polyethylene; Prosthesis