Experiences in limb salvage using mega prosthesis

Abstract

Megaprostheses are increasingly used in limb salvage after large tumor resections, severe fractures, or as a salvage procedure after complications to conventional arthroplasty. These prostheses are used in patients with a diversity in age, indication and tumor location. Aim: This thesis aimed to report on incidence, type, outcome, and complications as well as the patients’ experience of complications of megaprosthesis surgery, and to evaluate a novel method for diagnosing of aseptic loosening of distal femur megaprostheses reconstructions. Methods: Medical records for all patients provided with a megaprosthesis at Sahlgrenska University Hospital in 2006–2019 were evaluated. Data regarding complications, reoperations, indication for surgery, and prosthesis survival over time were collected (Studies I and II). A subgroup of patients was interviewed after treatment for a periprosthetic infection, and the data were qualitatively analyzed using a phenomenological method (Study III). CT-RSA with induced displacement was applied in a cohort of patients with pain after a distal femur megaprosthesis, to determine the movements between bone and implant, and its relation to patients’ pain scoring (Study IV). Results: In total, 114 patients with 116 megaprostheses were included. Fifty-six percent underwent at least one reoperation. Infection was the most common complication, diagnosed in 35/114 patients. Amputation was performed in 16 patients, nine for infection and seven for tumour relapse. At the end of follow-up (1.3–13.3 years), 83% of the patients had a functional prosthesis (Studies I and II). In the interviews conducted with patients treated for periprosthetic infections, the infection and its treatment were found to have had large impact on both physical function and self-image (Study III). In CT-RSA with induced displacement, movement in translation varied between 0.11 and 3.46 mm and in rotation between 0 and 2.95º in the investigated cohort. Making a pain drawing indicating severe pain characteristics corresponded well with a measured suspected pathological movement between bone and implant (Study IV). Conclusions: Megaprostheses are a reliable method for reconstruction of large skeletal defects but are associated with a high frequency of complications. Especially periprosthetic infections are demanding to treat and had clear effects on the patient’s experienced function and self-image. CT-RSA with induced displacement might be a valuable method for diagnosing aseptic loosening, but further studies are warranted.