Jordy van Sambeeck

Chapter 8 128 The presence of ceiling and floor effects was evaluated using the percentages of patients having the maximum or minimum score. We used the definition by Terwee 21 : there are no floor or ceiling effects if less than 15% of patients have minimum or maximum score. Results Ninety-seven patients filled out and completed the online questionnaires. The average time after surgery was 56 months (range 8 to 127 months). The descriptive of the scores are presented in table 1. The internal consistency of the NPI and BPII score was excellent with a Cronbach’s α of 0.972, and of 0.967 respectively. Mean (SD) Median (min-max) % Floor % Ceiling NPI Score 25 (23) 22 (0-87) 17 0 Banff 58 (22) 55 (10-100) 0 1 Kujala 73 (19) 77 (25-100) 0 5 NRS pain active 33 (28) 30 (0-100) 23 1 NRS pain rest 15 (21) 0 (0-80) 55 0 NRS disability 24 (26) 12 (0-95) 18 0 NRS instability 36 (33) 30 (0-100) 12 2 NRS satisfaction 70 (32) 80 (0-100) 6 23 KOOS symptoms 77 (19) 79 (14-100) 0 12 KOOS pain 79 (22) 86 (11-100) 0 20 KOOS ADL 85 (20) 93 (12-100) 0 26 KOOS Sports 47 (31) 45 (0-100) 10 8 KOOS QoL 56 (24) 50 (0-100) 2 6 SF 36 PF 76 (22) 80 (10-100) 0 15 SF 36 RP 80 (33) 100 (0-100) 9 66 SF 36 RE 89 (27) 100 (0-100) 6 83 SF 36 SF 85 (18) 88 (38-100) 0 50 SF 36 MH 63 (15) 60 (24-100) 0 2 SF 36 VT 69 (19) 70 (20-100) 0 5 SF 36 BP 75 (22) 78 (10-100) 2 20 SF 36 GH 73 (23) 80 (10-100) 0 7 Table 1. Mean outcome of the scores. Floor and ceiling effects are present if % floor or % ceiling >15% (bold italic numbers). ADL Activities of daily living, QoL quality of life, PF physical functioning, SF social functioning, RP role limitation resulting from physical problems, RE role limitation resulting from emotional problems, MHmental health, VT energy vitality, BP bodily pain, GH general health perception. Spearman correlation coefficients are presented in table 2. The criteria set for convergent validity for the BPII was met with strong correlations for SF 36 subscales