This case report concerns surgical decision making. The subject is a 59 year old male orthopaedic surgeon with medial compartment knee arthritis. Both high tibial valgus osteotomy and uni-compartmental knee replacement would be appropriate with similar outcomes reported in the literature. Surprisingly, almost all young surgeons recommended a uni-compartmental knee replacement and almost all older surgeons recommended a high tibial osteotomy. We discuss the reasons that surgeon age, which is clearly irrelevant to the optimal decision, is the dominant determinant of surgical recommendation for this patient.