Preoperative demand matching is a valid indicator of patient activity after total hip arthroplasty

The validity of preoperative demand matching as an indicator of patient activity following total hip arthroplasty (THA) was evaluated by studying 518 patients (mean age, 67 years; range, 26-92 years) who were assigned to 4 categories of decreasing demand: I (high demand), 68 patients (13%); II, 144 patients (28%); III, 281 patients (54%); and IV (low demand), 25 patients (5%). Preoperative Lahey Clinic Demand Category (as defined by age, weight, expected activity, health, and bone stock) was significantly correlated with self-reported, postoperative patient activity (P = .0038, R2 = .2024) and was much more predictive than any individual variable. Because patient activity is related to hip joint bearing surface wear, implant selection and resource allocation could be influenced by using demand matching to identify patients with high postoperative demand who may benefit from improvements in implant technology. Demand matching may also be used to stratify patient activity in long-term outcomes studies of THA.