Vascularized Small-Bone Transfers for Fracture Nonunion and Bony Defects

Reconstruction Options for Lower Extremity Traumatic Wounds

The senior author first coined the "orthoplastic" approach to traumatic lower extremity reconstruction, by which multidisciplinary surgeons and specialists work together for optimal patient success. The goals of lower extremity salvage are to optimize limb appearance, restore unrestricted pain-free ambulation, and improve quality of life. Composite traumatic defects require an organized approach, and the reconstructive ladder is used for strategies of varying complexity for repair of soft-tissue wounds. The lower rungs of the ladder include simpler reconstructive options such as the use of skin grafts and local flaps, and the higher rungs represent complex techniques such as free tissue transfer. Although there is no notable difference between muscle and fasciocutaneous/perforator flaps in reconstructive outcomes, there has been a trend toward perforator flaps to minimize donor site morbidity.

An antibody against Siglec-15 promotes bone formation and fracture healing by increasing TRAP+ mononuclear cells and PDGF-BB secretion

Osteoporosis (OP) is a common age-related disease characterized by a deterioration of bone mass and structure that predisposes patients to fragility fractures. Pharmaceutical therapies that promote anabolic bone formation in OP patients and OP-induced fracture are needed. We investigated whether a neutralizing antibody against Siglec-15 can simultaneously inhibit bone resorption and stimulate bone formation. We found that the multinucleation of osteoclasts was inhibited in SIGLEC-15 conditional knockout mice and mice undergoing Siglec-15 neutralizing antibody treatment. The secretion of platelet-derived growth factor-BB (PDGF-BB), the number of tartrate-resistant acid phosphatase-positive (TRAP⁺) mononuclear cells, and bone formation were significantly increased in the SIGLEC-15 conditional knockout mice and antibody-treated mice. The anabolic effect of the Siglec-15 neutralizing antibody on bone formation was blunted in mice with Pdgfb deleted in TRAP⁺ cells. These findings showed that the anabolic effect of the Siglec-15 neutralizing antibody was mediated by elevating PDGF-BB production of TRAP⁺ mononuclear cells. To test the therapeutic potential of the Siglec-15 neutralizing antibody, we injected the antibody in an ovariectomy-induced osteoporotic mouse model, which mimics postmenopausal osteoporosis in women, and in two fracture healing models because fracture is the most serious health consequence of osteoporosis. The Siglec-15 neutralizing antibody effectively reduced bone resorption and stimulated bone formation in estrogen deficiency-induced osteoporosis. Of note, the Siglec-15 neutralizing antibody promoted intramembranous and endochondral ossification at the damaged area of cortical bone in fracture healing mouse models. Thus, the Siglec-15 neutralizing antibody shows significant translational potential as a novel therapy for OP and bone fracture.

The Medial Femoral Condyle Free Flap for Reconstruction of Recalcitrant Defects in the Head and Neck

BACKGROUND

Small recalcitrant defects of the mandible and maxilla may be secondary to tumor, trauma, infection, and congenital origin. Vascularized bone grafting has been shown to effectively manage these defects; however, donor sites are limited. The vascularized medial femoral condyle (MFC) provides adequate cortical cancellous bone with the option of a skin island, consistent anatomy, and minimal donor site morbidity. This article outlines the use of the MFC flap for maxillomandibular reconstruction.

METHODS

A retrospective chart review of patients who required segmental maxillomandibular reconstruction with the MFC flap was conducted. A total of 9 patients (5 men and 5 women) with an average age of 45.3 years were identified. The etiology of the defects, flap sizes, and postoperative outcomes were recorded.

RESULTS

Three patients had osteoradionecrosis of the neomandible after irradiation of the free fibula reconstruction, 3 patients had defects after cancer extirpation (1 mandible, 2 maxillary), 1 patient had a maxillary defect from trauma, and 2 patients had a residual cleft palate defect. All defects failed initial treatment with nonvascularized bone grafts. The average dimensions of the MFC flaps were 1.2 × 2.5 × 4 cm. Two of 9 flaps included a skin island. Eight flaps survived completely, but 1 patient suffered from flap failure requiring debridement and resulted in an oroantral fistula. Four patients received endosseous dental implants. Average time to union was 6.7 months, and average time to implant was 6.75 months. The average follow-up time was 24.9 months.

CONCLUSIONS

The MFC flap is useful in the reconstruction of small segmental maxillomandibular defects and for the salvage of a neomandible after osteoradionecrosis. The MFC flap provides a reliable platform for endosseous dental implants and serves as an alternative source of vascularized bone reconstruction in the head and neck.

Medial Femoral Condyle Vascularized Bone Graft for Treatment of Midshaft Clavicle Recalcitrant Nonunion With Use of the Transverse Cervical Artery as an Anastomosis

Vascularized medial femoral condyle bone grafts have been reported to be a reliable treatment for recalcitrant bony nonunions of the extremities. Although clavicle fracture nonunions are rare after treatment with open reduction internal fixation, symptomatic nonunions can be a challenge. The medial femoral condyle vascularized bone graft has been described as a treatment option for clavicle nonunions with the thoracoacromial trunk as the recipient anastomosis site. This case illustrates how the transverse cervical artery and accompanying veins can be used as an anastomosis when the thoracoacromial trunk is inaccessible because of previous surgical- and infection-related scaring. At the final follow-up, the patient had returned to full duty and resumed competitive triathlons. Radiographs demonstrated complete healing of clavicle fracture.

CircRNA hsa_circ_0074834 promotes the osteogenesis-angiogenesis coupling process in bone mesenchymal stem cells (BMSCs) by acting as a ceRNA for miR-942-5p

Bone tissue has a strong ability to repair itself. When treated properly, most fractures will heal well. However, some fractures are difficult to heal. When a fracture does not heal, it is called nonunion. Approximately, 5% of all fracture patients have difficulty healing. Because of the continuous movement of the fracture site, bone nonunion is usually accompanied by pain, which greatly reduces the quality of life of patients. Bone marrow mesenchymal stem cells (BMSCs) play an important role in the process of nonunion. Circular RNAs (circRNAs) are a unique kind of noncoding RNA and represent the latest research hotspot in the RNA field. At present, no studies have reported a role of circRNAs in the development of nonunion. After isolation of BMSCs from patients with nonunion, the expression of circRNAs in these cells was detected by using a circRNA microarray. Alkaline phosphatase and Alizarin red staining were used to detect the regulation of osteogenic differentiation of BMSCs by hsa_circ_0074834. The target gene of hsa_circ_0074834 was detected by RNA pull-down and double-luciferase reporter assay. The ability of hsa_circ_0074834 to regulate the osteogenesis of BMSCs in vivo was tested by heterotopic osteogenesis and single cortical bone defect experiments. The results showed that the expression of hsa_circ_0074834 in BMSCs from patients with nonunion was decreased. Hsa_circ_0074834 acts as a ceRNA to regulate the expression of ZEB1 and VEGF through microRNA-942-5p. Hsa_circ_0074834 can promote osteogenic differentiation of BMSCs and the repair of bone defects. These results suggest that circRNAs may be a key target for the treatment of nonunion.

A Review on the Orthoplastic Approach to Lower Limb Reconstruction

Just as in the craft of carpentry, a stable foundation and framework are absolutely essential to the final function of a building, but no more important than the drywall, trim, and paint that make the building functional, durable, and livable. Reconstruction of the lower extremity is similar; the orthopaedic surgeon must obtain stable fixation of the damaged or diseased bone once a thorough debridement of nonviable bone is performed, while the plastic or orthopaedic soft tissue surgeon must provide vascularized, stable coverage. These two components are complementary and both contribute to the success or failure of functional limb restoration. The stability of bone repair will predict the ultimate functional status, while the vascularized envelope will enhance the biology of bone and soft tissue healing. When both components are properly attended to, the result is often a functional limb with an acceptable appearance. While a single surgeon need not perform both of these tasks (although some may choose to do so), the orthopaedic and plastic surgeon involved in this care must have a clear understanding of each other's role and their importance for a good outcome. This is what we call the orthoplastic approach to reconstructive surgery of the extremities, that is, the application of principles and practice of both specialties applied simultaneously to optimize the outcomes in limb reconstruction. In this review article, we discuss the history of orthoplastic surgery, the key elements of orthoplastic surgery, and thoughts on factors that lead to good outcomes through select cases.

Donor-Site Morbidity of Vascularized Bone Flaps from the Distal Femur: A Systematic Review

BACKGROUND

Vascularized grafts from the femur, including the medial femoral condyle and medial femoral trochlea, are increasingly being used. It is critical to understand the lower extremity complications from flap harvest.

METHODS

The authors searched available literature reporting on femoral flaps using PubMed, Embase, Cochrane Database, and Web of Science. After article selection, data were collected regarding demographics, procedure details, outcomes, and complications. The authors classified outcomes as good, fair, or poor based on pain, range-of-motion, sensory changes, subjective reporting, patient-reported outcomes, and other donor-site complications, including the need for additional procedures.

RESULTS

Two hundred twenty articles were identified. Forty-five met criteria for review, with data available for 283 patients. No patients had range-of-motion deficits beyond 1 year. Two percent of patients (six of 283) required additional donor-site procedures, with one report of a femur fracture after medial femoral condyle harvest. Only one study on 45 medial femoral trochlea patients presented patient-reported outcomes regarding the knee. Few objective data were presented. Twenty-eight articles presented adequate complication data for 252 patients to be rated as good, fair, or poor. Overall, 89 percent had good outcomes without donor-site complications. Of the 176 medial femoral condyle patients with outcomes reported, 92 percent had good outcomes; and 71 percent of the 48 medial femoral trochlea patients had good outcomes reported.

CONCLUSIONS

Overall, the reported donor-site morbidity from medial femoral condyle and medial femoral trochlea harvest is low. Chronic knee pain and sensory changes are most frequently reported, especially in medial femoral trochlea patients.