Effects of standard surgical procedures on the patellar blood flow in monkeys.

The effects of various surgical dissections on the patellar blood flow were studied in ten monkeys by the use of the hydrogen washout technique. The patellar blood flow was decreased to an average of 65% of the control value after an extensive medial parapatellar arthrotomy. When the infrapatellar fat pad was completely removed following extensive medial arthrotomy, the blood flow further decreased to an average of 49% of the control. When a lateral retinacular release with sacrifice of the lateral superior genicular artery was performed following the medial arthrotomy, the blood flow decreased to an average of 53% of the control. When a lateral release was combined with removal of the fat pad following the main medial arthrotomy, the patellar blood flow showed marked decrease to an average of only 17% of the control. The vascular anatomic study demonstrated that many vessels penetrate from the fat pad into the inferior pole of the patella. It is suggested that the lateral superior genicular artery and/or the fat pad should be carefully preserved to avoid ischemia of the patella during extensive procedures such as total knee arthroplasty.