Scintigraphic assessment of patellar viability in total knee arthroplasty after lateral release.

To what extent lateral retinacular release done in total knee arthroplasty compromises patellar viability has been debated. This study is a prospective study to assess patellar viability using Technetium-99m methylene diphosphate (Tc-99m MDP) scintigraphy. Between 2005 and 2006, 59 patients (72 knees) who underwent primary total knee arthroplasty were studied, of which 36 required lateral release. All patients underwent regional bone scan using Tc-99m MDP before and 1 to 3 weeks after the surgery. Two nuclear medicine consultants using both qualitative and quantitative assessment interpreted the scans independently. Fourteen knees with lateral release showed scintigraphic signs of hypovascularity in the early postoperative period that normalized in 8-week postoperative period. This study documents the greater incidence of transient patellar hypovascularity associated with lateral release.