A comparison of function after limb salvage with non-invasive expandable or modular prostheses in children

Modular and non-invasive expandable prostheses have been developed to provide a functional knee joint that allows future expansion as growth occurs in the contralateral extremity in children with bone sarcomas that require removal of the growth plate. This study aimed to evaluate the functional outcomes of paediatric patients who received either a non-invasive expandable or modular prosthesis for bone sarcomas arising around the knee.

We evaluated clinician-reported, patient-reported and measured function in 42 paediatric patients at least one year (median age at assessment 19.1 years) after limb salvage surgery, and compared patients who received modular system prostheses (N = 29, median age 15.5), who did not require lengthening procedures to those who received non-invasive expandable prostheses (N = 13, median age 11.1) requiring lengthening procedures (median 5).

The number of revisions and time to first revision did not differ between the two groups. There were no differences between the two groups in total scores on the Enneking Musculoskeletal Tumor Society Scale, the Toronto Extremity Salvage Scale, and the Functional Mobility Assessment. Children with non-invasive expandable prostheses climbed stairs (11.93 ± 4.83 versus 16.73 ± 7.24 s, p = 0.02) in less time than those with modular prostheses.

Our results suggest that the non-invasive expandable prosthesis produces similar functional results to the more traditional modular prosthesis.