Poster 46: Functional Outcomes After Limb Salvage Surgery and Endoprosthetic Reconstruction With an Expandable Prosthesis: A Case Series

Abstract

Objective: To determine the functional outcomes of skeletally immature patients after replacement of the femur and tibia using noninvasive expandable endoprostheses. Design: Case series. Setting: A hospital-based ambulatory care center. Participants: 4 pediatric patients with primary bone tumors of the distal femur and proximal tibia who underwent surgical replacement using a noninvasive expandable endoprosthesis. Interventions: Wide resection of bone sarcoma and placement of expandable endoprosthesis. Main Outcome Measures: Musculoskeletal Tumor Society (MSTS) scores were assessed at the beginning of the study and at each follow-up visit. Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), gait, sit-to-stand transition, and range of motion (ROM) were assessed at an average follow-up of 31.5 months. Results: At an average of 31.5 months postoperation, SF-36 Physical Component Summary scores lagged behind the national mean while Mental Component Summary scores were satisfactory. MSTS scores indicated low levels of pain or supports use and high emotional acceptance and walking ability, but persisting difficulties with function and gait. Patients also showed altered patterns of sit-to-stand transition, including decreased peak vertical force in the operated limb and increased center of mass momentum in a shorter amount of time. Parts of gait functioning were found to be decreased, including gait velocity, stride length, and cadence. Some patients displayed alternate weight-bearing strategies that accompanied increased double-limb support and stance phase during walking. ROM and strength were diminished at both the hip and knee joints in the operated limb as well as in the nonoperated limb. Conclusions: Reconstruction with a noninvasive, expandable endoprosthesis produces satisfactory functional outcomes in pediatric patients with primary tumors of the bone. Patients in our study displayed some persistent physical difficulties, including decreased ROM and strength and altered gait and sit-to-stand patterns, yet maintained high levels of emotional acceptance and coping.