Pediatric floating knee injuries: Clinical modifiers affecting sports and transfer outcomes.

AIM: This study assessed the functional outcome, and the clinical modifiers that influence them with the aim to assist the clinician plan a better management strategy in Paediatric Floating Knee (PFK) injuries.

METHODS: A quasi-prospective, single-center observational study was designed to determine the functional and radiological outcomes in children (</= 16 years), with minimum 1 year follow-up after treatment for PFK from 01-01-2014 to 01-08-2019. A retrospective audit was conducted, and a prospective patient/parent reported outcome score was determined with the Pediatric Outcome Data Collection Instrument (PODCI) questionnaire for 'transfer and mobility' and 'sports and physical function'.

RESULTS: Of 32 patients with PFK injury, twenty-five patients with a mean follow-up of 43 months (SD = 18) who completed the PODCI questionnaire were analysed. Fourteen (56%) children had open fractures (Lett's D or E types) with 6 open femur and 12 open tibia fractures. Majority underwent surgical fixation, 8 children required staged reconstruction and 11 children required soft tissue procedure in the ipsilateral limb. The mean time to union for femur and tibia fractures was 3.86 months (SD = 5.3) and 3.5 months (SD = 2.9), respectively with delayed union/non-unions in 3 femoral and 4 tibial fractures. The mean knee range of movement (RoM) was 102° (SD = 34.1) with limb shortening in 6 children, and overgrowth in 3 children. The mean normative PODCI (transfer) score was 35.6 (normal range: -74 to 52) and mean PODCI (sports) score was 37.6 (normal range: -33 to 56). Both the PODCI scores demonstrated strong inverse correlation with higher ISS(p < 0.01) and > 4 cm of bone loss (p < 0.01) but poor correlation with age at injury (p = 0.5), open fracture (p = 0.17), comminuted femoral and/or tibial fracture patterns (p > 0.05) and loss of soft tissue cover (p = 0.08).

CONCLUSIONS: Early recognition of clinical modifiers such as high ISS and bone loss > 4 cm warrants targeted limb reconstruction strategy and can help to prognosticate outcome.