This patient with a silastic arthroplasty has late stage synovitis from the implant. Normal laboratory values involving the white blood cell count, crp and esr help rule out infection as well as the clinical finding that the erythema mostly resolves with elevation.
Kitaoka et al showed that removal of the implant and synovectomy of failed silastic arthroplasties of the 1st metatarsophalangeal joint was an effective first line surgical treatment. Of the 10 patients they were able to get follow up on, 7 had excellent results, 1 had good results, one had fair results, and 1 did poorly. Kitaoka et al showed that lateral forefoot pressures increased following implant removal, but there was no significant change in overall alignment.
More recent studies and review articles such as by Esway et al have shown that implant removal and synovectomy can improve patient satsifaction after a failed arthroplasty. The decision to treat a failed arthroplasty with arthrodesis versus just implant removal depends on the functional demands of the patient and alignment of the foot.
Kitaoka HB, Holiday AD Jr, Chao EY, Cahalan TD. Salvage of failed first metatarsophalangeal joint implant arthroplasty by implant removal and synovectomy: clinical and biomechanical evaluation.Foot and Ankle, 13:1992 al,
PMID:1624187 (Link to Abstract)
Coughlin MJ: Arthritides, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby, 1999, pp 560-650
Esway JE, Conti SF. Joint replacement in the hallux metatarsophalangeal joint. Foot Ankle Clin. 2005 Mar;10(1):97-115.
PMID:15831260 (Link to Abstract)