PURPOSE: To evaluate the incidence of secondary hyperparathyroidism (SH) among postmenopausal women with end-stage knee osteoarthritis scheduled for total knee replacement (TKR).METHODS: 283 Caucasian postmenopausal women aged 49 to 81 (mean, 70) years with end-stage idiopathic knee osteoarthritis were scheduled to undergo primary TKR. They had been menopausal for 7 to 31 (mean, 19) years. Their preoperative serum levels of intact parathyroid hormone (I-PTH), calcium, phosphorus, creatinine, and the clearance of creatinine were evaluated.RESULTS: 100 patients had abnormally elevated serum I-PTH. The overall incidence of SH was 35%. Serum levels of calcium and phosphorus were elevated in 33 and 12 patients, respectively. The serum level of I-PTH correlated positively with patient age (r=0.158, p=0.008) and serum creatinine level (r=0.138, p=0.021) and negatively with clearance of creatinine (r= -0.169, p=0.004).CONCLUSION: SH is common among elderly postmenopausal women and may affect bone healing and implant fixation. Preoperative screening/evaluation of the serum PTH level in postmenopausal women scheduled for TKR is recommended.