Infective complications in tumour endoprostheses implanted after pathological fracture of the limbs.
INTRODUCTION
Pathological fractures represent an adverse prognostic factor in primary and metastatic bone tumours. The purpose of this study was to evaluate the results of tumour silver-coated prosthesis implanted after pathological fractures.


MATERIALS AND METHODS
A retrospective analysis was conducted on 30 patients with pathological limb fracture after primary or metastatic bone tumours treated by the same surgeon with wide margin resection and tumour prosthesis implant between 2005 and 2015. Silver-coated prostheses were implanted in 17 patients and uncoated prostheses were implanted in 13 patients. The primary outcome of the study was to evaluate the infective risk, the secondary outcomes were survival and functional level (visual analogue scale [VAS], 36-Item Short Form Health Survey [SF 36], and Musculoskeletal Tumour Society [MSTS] score) obtained at the longest follow-up available. A multivariate analysis was performed considering age, sex, tumour histology, grading and location, resection size, concomitant radiotherapy/chemotherapy, use of mesh for soft tissue reconstruction and local complications (dislocation, relapse, implant breakage). Scanning electron microscopy (SEM) analysis of explanted prosthesis was performed to study the residual silver-coating.


RESULTS
The average age of patients in the study was 56.2 years (range 12-78 years). Silver-coated prostheses were implanted in 56.7% of patients, and uncoated tumour prostheses were used in the remaining 43.3%. The mean follow-up was 40.7 months. A total of 26.7% of patients died at a median time of 28.6 months after surgery. The overall rate of complications was 30%, with 16.7% due to infection. A total of 11.8% of the patients treated with silver-coated implants developed infection compared with 23.1% of the patients treated with uncoated tumour prostheses. There were no cases of early infection in the silver-coated prosthesis group, whereas early infection occurred in 66.7% of patients in the uncoated prosthesis group. All the functional outcomes were significantly improved after surgery. None of the other parameters analysed can be considered a significant negative prognostic factor for infection. The SEM analyses showed severe silver-coating degradation 2 years after first implant. No case of silver toxicity was demonstrated.


DISCUSSION
There are few papers in the literature about infective complications in tumour prosthesis after pathological fracture. Silver-coated implants showed a protective action against early infection. Late infection rate was similar between the groups, thereby indicating a reduction of antimicrobial activity for the silver-coating over time.


CONCLUSIONS
Silver-coated prostheses are a protective factor against early infections in limb salvage surgery after pathological fractures, so may represent the first-choice of implants in this type of surgery.
['Piccioli|Andrea|A|', 'Donati|Fabrizio|F|', 'Giacomo|Giulio Di|GD|', 'Ziranu|Antonio|A|', 'Careri|Silvia|S|', 'Spinelli|Maria Silvia|MS|', 'Giannini|Silvana|S|', 'Giannicola|Giuseppe|G|', 'Perisano|Carlo|C|', 'Maccauro|Giulio|G|']
D000293:Adolescent D000328:Adult D000368:Aged D001859:Bone Neoplasms D002648:Child D020099:Coated Materials, Biocompatible D003362:Cost-Benefit Analysis D005260:Female D005269:Femur D005500:Follow-Up Studies D050723:Fractures, Bone D005598:Fractures, Spontaneous D006801:Humans D007558:Italy D023821:Limb Salvage D008297:Male D008875:Middle Aged D009364:Neoplasm Recurrence, Local D019919:Prosthesis Implantation D016459:Prosthesis-Related Infections D012189:Retrospective Studies D012834:Silver D015996:Survival Rate D013977:Tibia D016896:Treatment Outcome D055815:Young Adult
Infection Pathological fracture Limb salvage Megaprosthesis Oncological prosthesis Silver coating