учреждение «Российский научный центр "Восстановительная травматология и ортопедия" им. акад. Г.А. Илизарова» Министерства здравоохранения Российской Федерации, г. Курган, Россия; 2 Федеральное государственное бюджетное образовательное учреждение высшего образования «Тюменский государственный медицинский университет» Министерства здравоохранения Российской Федерации, г. Тюмень, Россия Combined bone plasty interventions for rehabilitation of patients with congenital pseudarthrosis of the tibia

BACKGROUND The Ilizarov bone transport (IBT) and the Masquelet induced membrane technique (IMT) have specific merits and shortcomings, but numerous studies have shown their efficacy in the management of extensive long-bone defects of various etiologies, including congenital deficiencies. Combining their strong benefits seems a promising strategy to enhance bone regeneration and reduce the risk of refractures in the management of post-traumatic and congenital defects and nonunion that failed to respond to other treatments. AIM To combine IBT and IMT for the management of severe tibial defects and pseudarthrosis, and present preliminary results of this technological solution. METHODS Seven adults with post-traumatic tibial defects (subgroup A) and nine children (subgroup B) with congenital pseudarthrosis of the tibia (CPT) were treated with the combination of IMT and IBT after the failure of previous treatments. The mean number of previous surgeries was 2.0 ± 0.2 in subgroup A and 3.3 ± 0.7 in subgroup B. Step 1 included Ilizarov frame placement and spacer introduction into the defect to generate the induced membrane which remained in the interfragmental gap after spacer removal. Step 2 was an osteotomy and bone transport of the fragment through the tunnel in the induced membrane, its compression and docking for consolidation without grafting. The outcomes were retrospectively studied after a mean follow-up of 20.8 ± 2.7 mo in subgroup A and 25.3 ± 2.3 mo in subgroup B. RESULTS The “true defect” after resection was 13.3 ± 1.7% in subgroup A and 31.0 ± 3.0% in subgroup B relative to the contralateral limb. Upon completion of treatment, defects were filled by 75.4 ± 10.6% and 34.6 ± 4.2%, respectively. Total duration of external fixation was 397 ± 9.2 and 270.1 ± 16.3 d, including spacer retention time of 42.4 ± 4.5 and 55.8 ± 6.6 d, in subgroups A and B, respectively. Bone infection was not observed. Postoperative complications were several cases of pin-tract infection and regenerate deformity in both subgroups. Ischemic regeneration was observed in two cases of subgroup B. Complications were corrected during the course of treatment. Bone union was achieved in all patients of subgroup A and in seven patients of subgroup B. One non-united CPT case was further treated with the Ilizarov compression method only and achieved union. After a follow-up period of two to three years, refractures occurred in four cases of united CPT. CONCLUSION The combination of IMT and IBT provides good outcomes in post-traumatic tibial defects after previous treatment failure but external fixation is longer due to spacer retention. Refractures may occur in severe CPT.

Relevance Defects of long bones result in anatomical and functional complex of pathologies in the entire limb. There are few fundamental studies of tissues adjacent to bone defects by using different technologies for management of long bone defects. Purpose To study the structural changes in the synovial membrane of the knee joint by modelling the conditions for tibial defect management using the Ilizarov method of non-free bone plasty in combination with the Masquelet technique. Materials and methods The conditions of post-resection defect of the tibia (from 15 % of the segment length) by lengthening the distal fragment were modeled in ten mongrel dogs. Temporarily, for 30 days, a cement spacer was implanted into the post-resection defect gap. Upon its removal, the intermediate fragment in the lower third of the leg was transported at a rate of 1 mm in 4 steps until complete contact of the bone fragments. Histomorphometric studies of the synovium were carried out at the observation stages at the end of the fixation period (60 days) and after removing the apparatus (30 days). Results Two types of changes were revealed in the synovium: changes of a destructive nature without synovitis (30 % of cases) and with signs of synovitis (70 % of cases, 3 dogs had mild synovitis and 4 dogs had severe synovitis). Changes in the microvessels of the synovial membrane in synovitis indicated impaired microcirculation, high activity of angiogenesis and the development of hypervascularization. Conclusion Experimental management of the tibial bone defect by Ilizarov method in combination with the Masquelet technique revealed signs of synovitis of the knee joint in 70 % of cases using histophorphometry methods.

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