How To Salvage A Failed First MPJ Implant

By Graham A. Hamilton, DPM

   A challenging problem for any podiatric surgeon is surgically managing cases in which a silicone elastomer implant in the first metatarsophalangeal joint (MPJ) has failed. When patients initially present with this problem, they will complain of pain, deformity or both at either the first or lesser metatarsophalangeal joints.    The cause of the pain or deformity can be multifactorial. The possible causes may include: chronic synovitis and swelling around the implant; chronic skin fistulas; implant breakage or fragmentation; severe periarticular bony subsidence and erosion; or biomechanical disruption of first ray stability and resultant lesser metatarsophalangeal joint overload.    The use of silicone implants in the first MPJ was described initially in 1972 when the implant was a single-stemmed hemiprosthesis designed to replace the resected base of the proximal phalanx.1 Results of this hemi-implant proved unsatisfactory. Consequently, a flexible, double-stemmed, hinged prosthesis was developed.2 Advocates of these implants cited such benefits as restoration of hallux length, good joint mobility, restoration of nearly normal joint biomechanics, adequate correction of hallux valgus and a shorter recovery period.1-8    Other clinical studies were less supportive as researchers reported high complication rates and poor functional outcomes, particularly for the hemi-implants.9-12 In one study, 36 percent of patients who received a single-stem implant were dissatisfied with the results of the operation.13 Researchers have also reported distal amputation after implant insertion.14 More recent data suggest these implants have poor rates of survival in weightbearing joints and in younger patients and that over time, these devices have high rates of mechanical failure with resultant metatarsalgia.11-13,16-19

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