Long-term functional recovery in patients with custom-made 3D-printed anatomical pelvic prostheses following bone tumor excision.

BACKGROUND: Anatomical custom-made prostheses make it possible to reconstruct complicated bone defects following excision of bone tumors, thanks to 3D-printed technology. To date, clinical measures have been used to report clinical-functional outcome and provide evidence for the effectiveness of this new surgical approach. However, there are no studies that quantified the achievable recovery during common activities by using instrumental clinical-functional evaluation in these patients. RESEARCH QUESTION: What is the motor performance, functional outcome and quality of life in patients with custom-made 3D-printed pelvic prostheses following bone tumor? METHODS: To analyze motor performance, six patients performed motion analysis during five motor activities at follow-up of 32 ± 18 months. Joint angles, ground reaction forces and joint moments of the operated and contralateral limbs were compared. On-off activity of lower-limb muscles were calculated from electromyography and compared to a healthy matched population. To analyze functional outcome and quality of life, differences in measured hip abductor strength between limbs were evaluated, as well as clinical-functional scores (Harris Hip Score, Barthel Index, Musculoskeletal Tumor Society score), and quality of life (SF-36 health survey). RESULTS: We found only slight differences in joint kinematics when comparing operated and contralateral limb. The activity of gluteal muscles was normal, while hamstrings showed out-of-phase activities. Ground reaction forces and hip moments showed asymmetries between limbs, particularly in more demanding motor activities. We found a mean difference in hip abductor strength of 48 ± 82 N between limbs, good clinical-functional scores, and quality of life scores within normative. SIGNIFICANCE: Our study showed optimal long-term results in functional recovery, mainly achieved through recovery of the gluteal function, although minor impairments were found, which may be considered for future improvement of this innovative surgery. The effect of a more loaded contralateral limb on internal loads and long-term performance of the implant remains unknown and deserves further investigation.

Myxofibrosarcoma: Clinical and Prognostic Value of MRI Features.

Myxofibrosarcoma is one of the most common soft tissue sarcomas in the elderly. It is characterized by an extremely high rate of local recurrence, higher than other soft tissue tumors, and a relatively low risk of distant metastases.Magnetic resonance imaging (MRI) is the imaging modality of choice for the assessment of myxofibrosarcoma, which plays a key role in the preoperative setting of these patients. MRI features associated with the high risk of local recurrence are: high myxoid matrix content (water-like appearance of the lesions), high grade of contrast enhancement and presence of an infiltrative pattern ("tail sign"). On the other hand, MRI features associated with worse sarcoma specific survival are: large size of the lesion, deep location, high grade of contrast enhancement. Recognizing the above-mentioned imaging features of myxofibrosarcoma may be helpful in stratifying the risk for local recurrence and disease-specific survival. Moreover, the surgical planning should be adjusted according to the MRI features.