Double-rib composite free transfer to reconstruct a single-spared lower extremity defect

New options for vascularized bone reconstruction in the upper extremity

Originally described in the 1970s, vascularized bone grafting has become a critical component in the treatment of bony defects and non-unions. Although well established in the lower extremity, recent years have seen many novel techniques described to treat a variety of challenging upper extremity pathologies. Here the authors review the use of different techniques of vascularized bone grafts for the upper extremity bone pathologies. The vascularized fibula remains the gold standard for the treatment of large bone defects of the humerus and forearm, while also playing a role in carpal reconstruction; however, two other important options for larger defects include the vascularized scapula graft and the Capanna technique. Smaller upper extremity bone defects and non-unions can be treated with the medial femoral condyle (MFC) free flap or a vascularized rib transfer. In carpal non-unions, both pedicled distal radius flaps and free MFC flaps are viable options. Finally, in skeletally immature patients, vascularized fibular head epiphyseal transfer can provide growth potential in addition to skeletal reconstruction.

Interleukin-18-induced inflammatory responses in synoviocytes and chondrocytes from osteoarthritic patients

The major pathological changes of osteoarthritis (OA) include cartilage degeneration and synovial inflammation. Previous studies confirmed that interleukin-1 (IL-1) stimulates the secretion of multiple inflammatory factors in synoviocytes and chondrocytes. IL-18 is a member of the IL-1 superfamily. In this study, the pro-inflammatory effects of IL-18 on synoviocytes and chondrocytes in patients with OA were investigated. Knee synovial membrane and cartilage samples were obtained from OA patients, then primary cells were cultured. Synoviocytes and primary chondrocytes at different generations (primary, secondary and tertiary), were stimulated with IL-18, then inflammatory marker levels, including tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE₂) and cyclooxygenase-2 (COX-2), were measured using reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay. IL-1 receptor antagonist (IL-1Ra) was applied to interfere with the IL-18 stimulation of chondrocytes, and then the COX-2 expression in chondrocytes and the PGE2 levels in the medium were measured. The expression of IL-18 receptor α (IL-18Rα) and IL-18 receptor β (IL-18Rβ) in synoviocytes and chondrocytes was assessed, using RT-PCR. Our results showed that IL-18 stimulated the COX-2 and TNF-α expressions in primary synoviocytes, while increasing PGE₂ and TNF-α levels in the supernatant (P<0.05) of the culture medium in primary synoviocytes. IL-18 also induced high PGE₂ level production in second-generation synoviocytes (P<0.05). Moreover, IL-18 upregulated COX-2 and TNF-α mRNA in chondrocytes, while promoting PGE₂ and TNF-α (P<0.05) secretions in a dose-dependent manner. The induced effects were not attenuated by the addition of IL-1Ra (P<0.05). IL-18Rα was expressed in the chondrocytes and synoviocytes of 4/8 patients, while IL-18Rβ was expressed in the chondrocytes of 4/8 patients and in the synoviocytes of 2/8 patients. We conclude that IL-18 induces inflammatory responses in synoviocytes and chondrocytes and that this effect was correlated with, although not entirely dependent on, IL-1β.

Pedicled Vascularized Rib Transfer for Reconstruction of Clavicle Nonunions with Bony Defects: Anatomical and Biomechanical Considerations

BACKGROUND

Clavicular nonunions with large bony defects, although rare, are difficult to treat and often result from multiple failed attempts at surgical management. Reconstruction using vascularized bone graft is the accepted standard in cases of large osseous defects.

METHODS

An anatomical vascular corrosion study with cadaveric dissections and finite element analyses was designed to assess the feasibility of clavicular reconstruction with a musculo-osteous graft interposition based on a pedicled serratus anterior flap.

RESULTS

Rib vascularization through the serratus anterior was demonstrated, so that the thoracic branch of the thoracodorsal artery can been considered a secondary blood supply for the seventh and eighth ribs. Single and double pedicled rib transfers allowed for reconstruction with as much as 8 cm of bone loss. The maximal stress found in the single-rib reconstruction interfaces was located at the medial contact of the plate with the clavicle. It was 2.7-fold higher than the maximal stress of the medial bow of the intact clavicle. Conversely, the double-rib reconstruction had improved mechanical resistance. A case report using a single-rib transfer supported the biomechanical study by showing that the maximal risk of material loosening was located at the medial bone interface.

CONCLUSIONS

Double vascularized rib transfer as part of a serratus anterior flap should be used instead of single-rib transfer to reconstruct large clavicle defects. This technique is reproducible and does not require microvascular anastomoses. Therefore, it has potential advantages over free fibula transfer.

Management of large infected tibial defects with radical debridement and staged double-rib composite free transfer

Seven patients with tibial fractures complicated by large infected tibial defects were treated with a two-stage protocol. In the first stage, antibiotic-impregnated polymethylmethacrylate (PMMA) bead chains were used to obliterate the debrided osseous defect, and a meshed porcine skin was used for temporary wound coverage. In the second stage, the bead chains were removed, and the defects were reconstructed with a microvascularized double-rib and serratus anterior muscle composite free transfer. The interval between the first and second operations was 2 to 4 weeks. The bone defects ranged from 6 to 9 cm, and the skin defect areas ranged from 20 to 40 cm2. Wound healing and bony union was achieved in all seven cases. Minor pin track infection was seen in one patient. Stress fractures in two cases were successfully managed with patellar tendon short-leg bracing for 6 months in one case and a plate internal fixation in the other case. Within 2 years, all seven patients returned to light work without any external support, and all of their most recent radiographs showed good consolidation and hypertrophy of grafted rib bones. No occurrence of osteomyelitis was observed during an average follow-up of 37 months (out of a range of 24 to 50 months). We conclude that this treatment protocol provides rapid recovery from osteomyelitis and the double-rib graft is a useful, durable alternative for large tibial defect management.