Long-Term Clinical Outcomes of Intercalary Allograft Reconstruction for Lower-Extremity Bone Tumors.

BACKGROUND: Improved survival rates for patients with primary bone tumors of the extremities have increased the demand for reliable and durable reconstruction techniques. Some authors have stated that, after successful ingrowth, allografts are a durable long-term solution. This hypothesis is largely based on small studies with short-to-midterm follow-up. In order to determine the durability of intercalary allograft reconstructions in the lower extremities, we evaluated the long-term clinical outcomes at a minimum of 10 years. METHODS: All patients who received an intercalary allograft reconstruction in a lower extremity between 1980 and 2006 were included in this retrospective multicenter cohort study. One hundred and thirty-one patients with a median age of 19 years were included. Eighty-nine (68%) had a femoral reconstruction, and 42 (32%) had a tibial reconstruction. The most prevalent diagnoses were osteosarcoma (55%), Ewing sarcoma (17%), and chondrosarcoma (12%). The median follow-up was 14 years. A competing risk model was employed to estimate the cumulative incidences of mechanical failure and infection. Patient mortality or progression of the disease was used as a competing event. RESULTS: Nonunion occurred in 21 reconstructions (16%), after a median of 16 months, and was associated with intramedullary nail-only fixation (p < 0.01) and fixation with nonbridging plate(s) (p = 0.03). Allograft fracture occurred in 25 reconstructions (19%) after a median of 42 months (range, 4 days to 21.9 years). Thirteen (52%) of the allograft fractures occurred within 5 years; 8 (32%), between 5 and 10 years; and 4 (16%), at >10 years. With failure for mechanical reasons as the end point, the cumulative incidences of reconstruction failure at 5, 10, and 15 years were 9%, 14%, and 21%, respectively. CONCLUSIONS: Intercalary allograft reconstruction is an acceptable reconstructive option, mainly because of the absence of superior alternatives with a known track record. However, a considerable and continuing risk of mechanical complications should be taken into account. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Multiflora and Gram-Negative Microorganisms Predominate in Infections Affecting Pelvic Endoprostheses Following Tumor Resection.

BACKGROUND: Periprosthetic infections after pelvic reconstruction are common, with reported rates ranging from 11% to 53%. Management of these infections is troublesome, as they commonly necessitate multiple surgical interventions and implant removal. The epidemiology and outcomes of these infections are largely unknown. The aim of this study was to analyze the causative microorganisms and the clinical outcome of treatment in a series of patients with pelvic endoprostheses affected by infection following tumor resection. METHODS: In this retrospective, multicenter cohort study, we identified all patients who developed an infection after endoprosthetic reconstruction in periacetabular tumor resection, between 2003 and 2017. The microorganisms that were isolated during the first debridement were recorded, as were the number of reoperations for ongoing infection, the antimicrobial treatment strategy, and the outcome of treatment. RESULTS: In a series of 70 patients who underwent pelvic endoprosthetic reconstruction, 18 (26%) developed an infection. The type of pelvic resection according to the Enneking-Dunham classification was type P2-3 in 14 (78%) of these patients and type P2 in 4 (22%). Median follow-up was 66 months. Fourteen (78%) of the 18 patients with infection had a polymicrobial infection. Enterobacteriaceae were identified on culture for 12 (67%). Of a total 42 times that a microorganism was isolated, the identified pathogen was gram-negative in 26 instances (62%). Microorganisms associated with intestinal flora were identified 32 times (76%). At the time of latest follow-up, 9 (50%) of the patients had the original implant in situ. Of these, 2 had a fistula and another 2 were receiving suppressive antibiotic therapy. In the remaining 9 (50%) of the patients, the original implant had been removed. At the time of final follow-up, 3 of these had a second implant in situ. The remaining 6 patients had undergone no secondary reconstruction. CONCLUSIONS: Infections that affect pelvic endoprostheses are predominantly polymicrobial and caused by gram-negative microorganisms, and may be associated with intestinal flora. This differs fundamentally from mono-bacterial gram-positive causes of conventional periprosthetic joint infections and may indicate a different pathogenesis. Our results suggest that prophylaxis and empiric treatment may need to be re-evaluated. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.