Development and validation of the patient-rated ulnar nerve evaluation

Table 9 Results of factor analysis of the final PRUNE items at 3 and 24 months after surgery

Items on Final PRUNE	3 months after surgery				24 months after surgery
Items on Final PRUNE	Pain	Usual activity/role	Specific activity	SM symptoms	Pain	Usual activity/role	Specific activity	SM symptoms
Variance explained by factor (%)	22	16	20	21	30	19	18	18
Pain- worst	0.82	0.09	0.34	0.17	0.84	0.25	0.26	0.27
Pain-at rest	0.86	0.38	0.14	0.23	0.83	−0.12	0.32	0.38
Pain -in morning	0.77	0.38	0.27	0.14	0.86	0.09	0.25	0.32
Pain -after activity	0.63	0.28	0.26	0.16	0.74	0.13	0.29	0.27
Pain- at night	0.89	0.17	0.10	0.23	0.80	0.04	0.34	0.33
Pain- Frequency	0.68	0.14	0.24	0.36	0.71	0.21	0.21	0.34
SM-Numbness	0.06	0.26	0.19	0.86	0.36	0.19	0.15	0.87
SM- Pins and needles	0.24	0.25	0.10	0.82	0.39	0.25	0.20	0.80
SM-Control	0.36	−0.00	0.17	0.77	0.33	0.04	0.23	0.68
SM-Weakness in hand	0.06	0.15	0.44	0.69	0.34	0.37	0.48	0.59
SA-Eating with fork or spoon	0.30	0.26	0.60	0.10	−0.02	0.88	0.66	0.196
SA- Lift a heavy object	0.23	0.22	0.78	0.14	0.38	0.44	0.58	0.25
SA-Hold an object	0.30	0.47	0.58	0.26	0.37	0.123	0.88	0.14
SA- Finger Task	0.32	0.02	0.78	0.24	0.36	0.38	0.60	0.37
SA-Reaching	0.23	0.22	0.78	0.14	0.45	0.36	0.59	0.31
SA-Turning a doorknob	0.10	0.30	0.70	0.35	0.20	0.30	0.68	0.25
UA-Personal care	0.09	0.84	0.05	0.34	−0.02	0.89	0.27	0.06
UA-Household	0.32	0.76	0.25	0.35	0.28	0.52	0.45	0.11
UA-Work	0.35	0.78	0.34	0.00	0.32	0.68	0.26	0.06
UA-Recreational activities	0.36	0.78	0.36	0.19	0.44	0.58	0.48	0.21

Principal Component Analysis with Varimax with Kaiser Normalization. Factor loadings are color-coordinated to highlight loading over 0.40. (Pain subscale items in bold, sensory/motor (SM) symptoms items in italics (SM), specific activity items in underline (SA) and usual activity items in bold (UA). Overall, cross loading was minimal and items differentiated onto the anticipated subscales. Cross loading occurred for item on weakness in grip at both 3- and 24- month follow-up. At 2-year follow-up heavy object and recreational activities also demonstrated some cross-loading. Overall, the loading confirmed the subscale structure.

ISSN: 1471-2474