Detection of synovial pseudarthrosis by 99mTc scintigraphy: application to treatment of traumatic nonunion with constant direct current.

A prospective study utilizing technetium scintigraphy to evaluate nonunion patients prior to the electrical stimulation of osteogenesis is reported. Roentgenographic evaluation and scintigraphy must include four views (anteroposterior, lateral and both obliques). Although all nonunion technetium scans showed increased uptake of the radionuclide at the fracture site, three bone scan patterns were identified: (1) intense, uniformly increased uptake at the nonunion site (69.5%); (2) photon deficient (cold) cleft between two intense areas of uptake (23.4%); and (3) indeterminate pattern (7.1%). The presence of a cold cleft between two intense areas of uptake on scintigraphy correlated closely with the presence of a synovial pseudarthrosis at surgery. Nonunions of the humerus were most frequently associated with synovial pseudarthrosis (57.1%). The presence of a synovial pseudarthrosis as suggested by technetium scintigraphy mandates open excision of the lining membrane at the time of electrode insertion.