Union, complication, reintervention and failure rates of surgical techniques for large diaphyseal defects: a systematic review and meta-analysis

To understand the potential and limitations of the different available surgical techniques used to treat large, long-bone diaphyseal defects by focusing on union, complication, re-intervention, and failure rates, summarizing the pros and cons of each technique. A literature search was performed on PubMed, Web of Science, and Cochrane databases up to March 16th, 2022; Inclusion criteria were clinical studies written in English, of any level of evidence, with more than five patients, describing the treatment of diaphyseal bone defects. The primary outcome was the analysis of results in terms of primary union, complication, reintervention, and failure rate of the four major groups of techniques: bone allograft and autograft, bone transport, vascularized and non-vascularized fibular graft, and endoprosthesis. The statistical analysis was carried out according to Neyeloff et al., and the Mantel-Haenszel method was used to provide pooled rates across the studies. The influence of the various techniques on union rates, complication rates, and reintervention rates was assessed by a z test on the pooled rates with their corresponding 95% CIs. Assessment of risk of bias and quality of evidence was based on Downs and Black's "Checklist for Measuring Quality" and Rob 2.0 tool. Certainty of yielded evidence was evaluated with the GRADE system. Seventy-four articles were included on 1781 patients treated for the reconstruction of diaphyseal bone defects, 1496 cases in the inferior limb, and 285 in the upper limb, with trauma being the main cause of bone defect. The meta-analysis identified different outcomes in terms of results and risks. Primary union, complications, and reinterventions were 75%, 26% and 23% for bone allografts and autografts, 91%, 62% and 19% for the bone transport group, and 78%, 38% and 23% for fibular grafts; mean time to union was between 7.8 and 8.9 months in all these groups. Results varied according to the different aetiologies, endoprosthesis was the best solution for tumour, although with a 22% failure rate, while trauma presented a more composite outcome, with fibular grafts providing a faster time to union (6.9 months), while cancellous and cortical-cancellous grafts caused less complications, reinterventions, and failures. The literature about this topic has overall limited quality. However, important conclusions can be made: Many options are available to treat critical-size defects of the diaphysis, but no one appears to be an optimal solution in terms of a safe, satisfactory, and long-lasting outcome. Regardless of the bone defect cause, bone transport techniques showed a better primary union rate, but bone allograft and autograft had fewer complication, reintervention, and failure rates than the other techniques. The specific lesion aetiology represents a critical aspect influencing potential and limitations and therefore the choice of the most suitable technique to address the challenging large diaphyseal defects.