Advanced metacarpophalangeal (MCP) degenerative joint disease is increasingly being treated utilizing hinged, semiconstrained, and unconstrained arthroplasty implants [1]. Silicone, metallic, and pyrolytic carbon (PyroCarbon) implant-types have been engineered with relative patient-specific indications depending on presence of inflammatory arthritis, history of trauma to the joint, and involvement of MCP or proximal interphalangeal (PIP) joints [2]. For noninflammatory arthritis, PyroCarbon implants have proven to be beneficial for pain relief, resulting in functional range of motion, and high patient satisfaction [3].

PyroCarbon implants were originally designed in the field of Cardiology for bileaflet mechanical valve replacement. Since then, the field of Orthopaedic Surgery has expanded PyroCarbon applications to include replacements of small joints within the hand, radial heads, and even humeral heads [4], [5], [6], [7]. PyroCarbon can be used as an interposition implant or as a joint replacement as in this case. PyroCarbon is an ideal substrate as it has a modulus of elasticity that is most like cortical bone compared to other material. Thus, it is hypothesized to be a favorable option as it minimizes stress shielding by reducing stresses transmitted between implant and bone [8]. PyroCarbon consists of a graphite substrate coated with a thin layer (<1 mm) of pyrolytic carbon. No local toxicity, allergy, or immune responses have been documented across a variety of orthopedic implants and millions of mechanical heart valves in practice due to its well-studied inert and stable nature [8], [9].

While PyroCarbon implants may be extremely well-tolerated, they do not exist without failure. Postoperative complications of MCP arthroplasty with PyroCarbon implants include continued pain, flexion contracture of the involved joint, stiffness, loosening, subsidence, extensor tendon rupture, and implant fracture [10], [11]. In instances of implant fracture, black staining was present in the pericapsular tissue upon revision surgery. This staining was accompanied by focal pigment deposits without evidence of any intracellular particles or particulate synovitis [10]. Additionally, these findings have been described in humeral head resurfacing arthroplasty after noting fracture of the implant with surrounding debris on radiographs [12]. In these cases, patients presented symptomatically after an acute onset of symptoms that included pain and or limited range of motion.

Although fractures of PyroCarbon MCP joint implants have been previously described, to our knowledge, this case is the first detailing PyroCarbon implant breakdown without radiographic abnormality leading to revision surgery [13]. We report a case of a patient who originally underwent primary MCP arthroplasty of his long finger with satisfactory results, who then presented years later with concern for a septic prosthetic joint. During management with operative washout, the patient was discovered to have implant breakdown, accompanied by gross periarticular staining and debris, not demonstrated by radiograph.