Dutch translation and cross-cultural adaptation of the LIMB-Q Kids questionnaire

Table 1 Patient characteristics and treatment details

Patient number	Age at interview (years)	Sex	Diagnosis	Type of treatment	Stage of treatment at the time of interview
1	12	Female	Idiopathic limb length difference	Shoe raise	Ongoing
2	13	Female	Fibula hemimelia	Guided growth surgery	Guided growth and ongoing; lengthening
3	13	Female	Valgus alignment and limb length difference following developmental dysplasia of hip	Guided growth surgery and distal femur epiphysiodesis	Ongoing
4	10	Female	Transversal reduction defect	Symes amputation, epiphysiodesis; prosthesis	Surgical interventions finished; prosthesis ongoing
5	8	Female	Idiopathic valgus deformity	Conservative	No intervention
6	9	Male	Posttraumatic growth arrest tibia	Leg lengthening, unilateral external fixator	Lengthening ongoing
7	11	Female	Congenital hip dislocation, leg length difference	Pelvic osteotomies and femur osteotomy	Finished
8	10	Male	Hemi-hypertrophy (Beckwidth-Wiedeman)	Planned epiphysiodesis	Planned
9	13	Female	Congenital torsional deformity femur	Planned for derotation osteotomy	Awaiting surgery
10	9	Male	Posteromedial bowing of the tibia	Leg lengthening with ring fixator and hemi-epiphysiodesis	During lengthening

Table 2 Examples of discrepancies and changes made in the Dutch translation process

Name of scale	Item (English original version)	Forward translation	Problem in forward translation	Backward translation	Expert panel opinion	Cognitive debriefing interviews
Knees symptoms	My knee is swollen or puffy	Gezwollen of opgezet1; Opgezwollen2	At reconciliation meeting decided: ‘dik of opgezwollen’	‘My knee is thick or swollen’	Backward translation is not literally identical, but Dutch phrasing is best option to capture the intended meaning	No concerns raised
Leg-related distress	I get upset when my leg stops me from having fun	Ik raak van slag1; Ik raak van streek2	At reconciliation meeting decided ‘ik vind het vervelend’	‘I don’t like it when people look at my leg’	Double negative should be avoided, but was only present in the back translation and not in the Dutch translation	No concerns raised
Hip symptoms	My hip hurts when it makes sound (clicks or pops)	Mijn heup doet pijn als hij geluid maakt (klikt of plopt)1,2	No remarks	‘My hip hurts when it makes a noise (when it clicks or pops)’	Not identical, but similar meaning	Interviewed children suggested ‘klikt of knakt’ as a more relatable option, which we followed. This was well received in following CDIs
Physical function	… walk without a limp?	… lopen zonder mank te lopen?1; … zonder hinken te lopen?2	Both were not well-flowing formulations, decided to go for: ‘… lopen zonder strompelen?’	‘… walk without stumbling?’	We changed translation to ‘… lopen zonder hinken of manken?’ considering the backward translation this stays closest to the original ‘limp’	The chosen translation was not deemed adequate by several interviewees, especially the word ‘hinken’ was flagged. Suggestions from patients were sought and finally ‘lopen zonder mank te lopen’ was chosen. In subsequent CDIs this was confirmed to be an adequate translation

¹Forward translator one.

²Forward translator two.

CDI: Cognitive debriefing interview.