A 52-year-old man with CKD stage 4 (eGFR 22 mL/min/1.73m²) presents with bone pain and muscle weakness. Laboratory investigations show: serum calcium 7.2 mg/dL, phosphate 5.8 mg/dL, alkaline phosphatase 120 U/L, PTH 680 pg/mL. Bone biopsy reveals high bone turnover with increased osteoblastic and osteoclastic activity. Which feature best distinguishes secondary hyperparathyroidism-induced high-turnover bone disease from adynamic bone disease in CKD?