Table 2.

Secondary endpoints

No.	Outcome measurement	Follow-up time
1	Baseline data including height, weight, medical history, physical examination	Screening
2.	Hip outcome scores; Harris hip score [36], WOMAC [35]	Screening, 12, 24, 36 months
3.	Pain Numerical Rating Scale (PNRS), Activity Scores [27] and Health-related quality of life (EQ-5D) [37]	Screening, 12, 24, 36 months
4a	Percent change from baseline in BMD in vertebrae L1-L4 measured with dual-energy x-ray absorptiometry (DXA)	Screening, 36 months
5.	Correlation between change in bone turnover markers and progression of osteolysis. Serum C-terminal telopeptide of type I collagen (SCTx) [42] and procollagen type 1 amino-terminal propeptide (P1NP) [43].	Screening, 12, 24, 36 months
6.	Correlation between change in serum concentrate values for RANKL and Osteoprogesterin (OPG) and progression of osteolysisb.	Screening, 24,36 months
7.	Occurrence of adverse events	6, 12, 18, 24, 30, 36 months
8.	Radiological analysis plain x-ray	Screening, 36 months

^aPrevious studies on denosumab have focused on patients with osteoporosis or other metabolic bone disease and it is to be expected that the patients in this trial will have a normal bone mass

^bSerum levels of RANKL and OPG will be quantified by ELISA with commercially available matched antibodies [44, 45]