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

The Medial Femoral Trochlea Osteochondral Flap for Scaphoid Reconstruction: A Systematic Review

BACKGROUND

The medial femoral trochlea flap has been used to resurface scaphoids with recalcitrant proximal pole fractures or avascular necrosis, providing vascularized osteochondral tissue with similar morphological characteristics. This article aims to review the contemporary literature on its use for scaphoid reconstruction.

METHODS

A systematic review of Embase, PubMed, Cochrane Central Register of Controlled Trials, and MEDLINE assessed the use of medial femoral trochlea flaps in scaphoids.

RESULTS

Eight studies were included, with 76 patients at a mean age of 26 years. Forty-three patients underwent clinical review, and 10 patients underwent radiographic evaluation, at a mean 23.3 months of follow-up. Flaps were generally performed for proximal pole fractures, avascular necrosis, nonunion, or failure of prior fixation; 94.4% of the flaps united. No marked change in sagittal plane motion was noted; reductions were seen in axial and coronal plane motion. The Disabilities of the Arm, Shoulder, and Hand scores improved from a mean of 25.2 to 11.5. Radiographic markers also improved. A total of 12.3% of patients had unplanned return to theater. Three patients required early revision for vascular thrombosis, and 1 patient suffered a volar carpal dislocation. Three patients underwent salvage procedures for ongoing pain.

CONCLUSIONS

Although technically demanding, promising early-term to medium-term results are noted with the use of medial femoral trochlea flaps in the scaphoid.

Objective assessment of the effect of surgery on limb function after medial femoral condyle free flap harvest: biomechanical parameters

The aim of this study was to evaluate the influence of medial femoral condyle (MFC) free flap harvest on donor site muscle strength and kinematic parameters of gait. The study included 30 patients treated for head and neck squamous cell carcinoma who underwent reconstruction with an MFC free flap. In each case, the donor site was the left thigh. A dynamometer was used to measure muscle strength, in isokinetic bilateral mode and with concentric contraction for the extension/flexion knee pattern, at 18 months postoperative. In addition, kinematic data were obtained and evaluated. On statistical analysis, no significant difference in muscle strength of the quadriceps muscle was found between the left involved and right uninvolved lower extremities (P = 0.124). Also, when comparing hamstring strength, no statistically significant difference was found between the left involved and right uninvolved sides (P = 0.210). Moreover, spatiotemporal gait parameters did not differ significantly between the involved and uninvolved legs (all P > 0.05), and no differences in kinematic or kinetic parameters were observed. This study reports the effects of MFC free flap harvest on the knee muscle strength and locomotion of patients. For most biomechanical parameters investigated, there was no effect (positive or negative).

Calcium Orthophosphate (CaPO4) Containing Composites for Biomedical Applications: Formulations, Properties, and Applications

The goal of this review is to present a wide range of hybrid formulations and composites containing calcium orthophosphates (abbreviated as CaPO4) that are suitable for use in biomedical applications and currently on the market. The bioactive, biocompatible, and osteoconductive properties of various CaPO4-based formulations make them valuable in the rapidly developing field of biomedical research, both in vitro and in vivo. Due to the brittleness of CaPO4, it is essential to combine the desired osteologic properties of ceramic CaPO4 with those of other compounds to create novel, multifunctional bone graft biomaterials. Consequently, this analysis offers a thorough overview of the hybrid formulations and CaPO4-based composites that are currently known. To do this, a comprehensive search of the literature on the subject was carried out in all significant databases to extract pertinent papers. There have been many formulations found with different material compositions, production methods, structural and bioactive features, and in vitro and in vivo properties. When these formulations contain additional biofunctional ingredients, such as drugs, proteins, enzymes, or antibacterial agents, they offer improved biomedical applications. Moreover, a lot of these formulations allow cell loading and promote the development of smart formulations based on CaPO4. This evaluation also discusses basic problems and scientific difficulties that call for more investigation and advancements. It also indicates perspectives for the future.

Computer-aided designed 3D-printed polymeric scaffolds for personalized reconstruction of maxillary and mandibular defects: a proof-of-concept study

PURPOSE

To investigate the potential reconstruction of complex maxillofacial defects using computer-aided design 3D-printed polymeric scaffolds by defining the production process, simulating the surgical procedure, and explore the feasibility and reproducibility of the whole algorithm.

METHODS

This a preclinical study to investigate feasibility, reproducibility and efficacy of the reconstruction algorithm proposed. It encompassed 3 phases: (1) scaffold production (CAD and 3D-printing in polylactic acid); (2) surgical simulation on cadaver heads (navigation-guided osteotomies and scaffold fixation); (3) assessment of reconstruction (bone and occlusal morphological conformance, symmetry, and mechanical stress tests).

RESULTS

Six cadaver heads were dissected. Six types of defects (3 mandibular and 3 maxillary) with different degree of complexity were tested. In all case the reconstruction algorithm could be successfully completed. Bone morphological conformance was optimal while the occlusal one was slightly higher. Mechanical stress tests were good (mean value, 318.6 and 286.4 N for maxillary and mandibular defects, respectively).

CONCLUSIONS

Our reconstructive algorithm was feasible and reproducible in a preclinical setting. Functional and aesthetic outcomes were satisfactory independently of the complexity of the defect.

Vascularized Reconstruction of Recalcitrant Clavicular Nonunion with the Medial Femoral Condyle Free Flap: A Systematic Review of the Literature

Recalcitrant clavicular nonunion is an uncommon but challenging problem. Vascularized bone reconstruction is not first-line therapy due to complexity and donor morbidity, though it has utility in select cases. A systematic review of Embase and Medline databases was undertaken for cases of medial femoral condyle reconstruction for clavicle nonunion. Ten studies met inclusion, encompassing 26 patients. Mean age was 38.9 years. Ten patients were male and 16 female. Mean time of nonunion was 37.79 months prior to intervention; mean time to union following medial femoral condyle flap was 7.60 months. Two patients did not achieve union. Of the 11 patients who previously had at least one failed fixation with bone graft, considered the current "gold standard", 9 patients (81.81%) went on to achieve union, while 2 patients (18.19%) did not. There were six reported complications in five patients. Medial femoral condyle flap is a valuable option in recalcitrant clavicle nonunion.

Vascularized Medial Femoral Condyle Flap Reconstruction for Osseous Defects of the Hand and Wrist

Vascularized bone flaps from the descending genicular artery system are versatile and effective for the use of recalcitrant nonunions from the tubular bones of the hand to the long bones of the upper extremity. Familiarity with the vascular pedicle, various techniques of harvest and inset, and skin paddle harvest and application are essential for the reconstructive surgeon.

Patient-Reported Lower Extremity Outcomes Following Fibula or Medial Femoral Condyle Free Flaps for Upper Extremity Defects

BACKGROUND

Free fibula flap (FFF) and medial femoral condyle (MFC) flap are commonly used for upper extremity osseous reconstruction, yet donor-site morbidity has never been systematically compared.

METHODS

Patients who underwent an FFF or MFC for upper extremity extra-carpal osseous reconstruction at 3 academic hand centers were retrospectively identified. Only patients who underwent reconstruction for a defect in which either flap type is routinely used or has been described in the literature were deemed eligible. Patients who agreed to participate were asked to complete the Lower Extremity Functional Scale (LEFS) and Lower Limb Core Scale (LLCS). The reported population norm median score of LEFS is 77 points. The LLCS population norm mean score is 90.52 points.

RESULTS

Twenty-one patients (10 MFC, 11 FFF) were enrolled. The median LEFS score for patients after MFC was 76 (interquartile range [IQR], 49-80) points and 75 (IQR, 56-79) points after FFF. The median LLCS score for patients after MFC was 96.4 (IQR, 87.9-100) points and 100 (IQR, 91-100) points after FFF. Median LEFS scores were slightly below the population norm, whereas median LLCS scores were above the norm for both FFF and MFC. All patients stated they would have the surgery again and that any dysfunction or pain in the leg was justified by the benefit in the arm.

CONCLUSIONS

When considering whether to use an MFC or FFF for upper extremity reconstruction, both flap types appear to result in modest and comparable donor-site morbidity.

Medial Femoral Condyle Corticoperiosteal Flap for Failed Total Wrist Fusions

Background  Recalcitrant nonunion following total wrist arthrodesis is a rare but challenging problem. Most commonly, in the setting of failed fusion after multiple attempts of refixation and cancellous bone grafting, the underlying cause for the failure is invariably multifactorial and is often associated with a range of host issues in addition to poor local soft-tissue and bony vascularity. The vascularized medial femoral condyle corticoperiosteal (MFC-CP) flap has been shown to be a viable option in a variety of similar settings, which provides vascularity and rich osteogenic progenitor cells to a nonunion site, with relatively low morbidity. While its utility has been described for many other anatomical locations throughout the body, its use for the treatment of failed total wrist fusions has not been previously described in detail in the literature. Methods  In this article, we outline in detail the surgical technique for MFC-CP flap for the management of recalcitrant aseptic nonunions following failed total wrist arthrodesis. We discuss indications and contraindications, pearls and pitfalls, and potential complications of this technique. Results  Two illustrative cases are presented of patients with recalcitrant nonunions following multiple failed total wrist fusions. Conclusion  When all avenues have been exhausted, a free vascularized corticoperiosteal flap from the MFC is a sound alternative solution to achieve union, especially when biological healing has been compromised. We have been able to achieve good clinical outcomes and reliable fusion in this difficult patient population.

Single-cell RNA sequencing unravels heterogeneity of skeletal progenitors and cell-cell interactions underlying the bone repair process

Introduction

Activation of skeletal progenitors upon tissue injury and the subsequent cell fate specification are tightly coordinated in the bone repair process. Although known osteoimmunological signaling networks play important roles in the microenvironment of the bone defect sites, the molecular mechanism underlying the bone repair process has not been fully understood.

Methods

To better understand the behavior of the skeletal progenitors and the heterogeneity of the cells during bone repair at the microenvironmental level, we performed a combinatorial analysis consisting of lineage tracing for skeletal progenitors using the Sox9-CreERT2;R26R tdTomato mouse line followed by single-cell RNA sequencing (scRNA-seq) analysis using a mouse model of calvarial bone repair. To identify a therapeutic target for bone regeneration, further computational analysis was performed focusing on the identification of the cell-cell interactions, followed by pharmacological assessments with a critical-size calvarial bone defect mouse model.

Results

Lineage tracing analysis showed that skeletal progenitors marked by Sox9 were activated upon bone injury and contributed to bone repair by differentiating into osteoblasts. The scRNA-seq analysis characterized heterogeneous cell populations at the bone defect sites; the computational analysis predicted a bifurcated lineage from skeletal progenitors toward osteogenic and adipogenic lineages. Chemokine C-C motif ligand 9 (Ccl9) was identified as a signaling molecule that regulates bone regeneration in the mouse model, possibly through the regulation of adipogenic differentiation at the bone defect site.

Conclusion

Multipotential skeletal progenitors and the direction of the cell differentiation were characterized at single cell resolution in a mouse bone repair model. The Ccl9 signaling pathway may be a key factor directing osteogenesis from the progenitors in the model and may be a therapeutic target for bone regeneration.

Robust coupling of angiogenesis and osteogenesis by VEGF-decorated matrices for bone regeneration

Rapid vascularization of clinical-size bone grafts is an unsolved challenge in regenerative medicine. Vascular endothelial growth factor-A (VEGF) is the master regulator of angiogenesis. Its over-expression by genetically modified human osteoprogenitors has been previously evaluated to drive vascularization in osteogenic grafts, but has been observed to cause paradoxical bone loss through excessive osteoclast recruitment. However, during bone development angiogenesis and osteogenesis are physiologically coupled by VEGF expression. Here we investigated whether the mode of VEGF delivery may be a key to recapitulate its physiological function. VEGF activity requires binding to the extracellular matrix, and heterogeneous levels of expression lead to localized microenvironments of excessive dose. Therefore we hypothesized that a homogeneous distribution of matrix-associated factor in the microenvironment may enable efficient coupling of angiogenesis and bone formation. This was achieved by decorating fibrin matrices with a cross-linkable engineered version of VEGF (TG-VEGF) that is released only by enzymatic cleavage by invading cells. In ectopic grafts, both TG-VEGF and VEGF-expressing progenitors similarly improved vascularization within the first week, but efficient bone formation was possible only in the factor-decorated matrices, whereas heterogenous, cell-based VEGF expression caused significant bone loss. In critical-size orthotopic calvaria defects, TG-VEGF effectively improved early vascular invasion, osteoprogenitor survival and differentiation, as well as bone repair compared to both controls and VEGF-expressing progenitors. In conclusion, homogenous distribution of matrix-associated VEGF protein preserves the physiological coupling of angiogenesis and osteogenesis, providing an attractive and clinically applicable strategy to engineer vascularized bone. STATEMENT OF SIGNIFICANCE: The therapeutic regeneration of vascularized bone is an unsolved challenge in regenerative medicine. Stimulation of blood vessel growth by over-expression of VEGF has been associated with paradoxical bone loss, whereas angiogenesis and osteogenesis are physiologically coupled by VEGF during development. Here we found that controlling the distribution of VEGF dose in an osteogenic graft is key to recapitulate its physiological function. In fact, homogeneous decoration of fibrin matrices with engineered VEGF could improve both vascularization and bone formation in orthotopic critical-size defects, dispensing with the need for combined osteogenic factor delivery. VEGF-decorated fibrin matrices provide a readily translatable platform for engineering a controlled microenvironment for bone regeneration.

Reconstruction of the Fourth Metacarpal Using a Chimeric Medial Femoral Condyle Vascularized Osteochondral Cutaneous Graft: Case Report

BACKGROUND

The medial femoral condyle has become a matter of great interest, thanks to the possibility of harvesting versatile chimeric flaps for reconstruction of metacarpal defects with minimal donor site morbidity. This case stands out because of the complete reconstruction of the metacarpal head, harvesting with a skin paddle for tension-free closure and monitoring, and the use of external fixation for better predictability of the reconstruction and early postoperative mobilization.

CASE PRESENTATION

We report the case of a 20-year-old male patient who presented with an aneurysmal bone cyst involving the fourth metacarpal bone. The patient underwent resection en bloc of the metaphysis and distal epiphysis of the fourth metacarpal bone, and the bone defect was reconstructed using a 3.4-cm vascularized osteochondral cutaneous graft from the medial femoral condyle.

RESULTS

At 1-year follow-up, the patient showed no impairment in hand range of motion and had a Disabilities of Arm, Shoulder and Hand score inferior to that of the male healthy population. Almost 5 years after the procedure, the radiographic examination did not reveal signs of arthrosis. This case report shows that the medial femoral condyle is an excellent and versatile source of vascularized osteochondral grafts for reconstruction of metacarpal defects.

Supine harvest of vascularised scapular bone grafts-Anatomical study and clinical application

BACKGROUND

We report our findings from an anatomical study on harvest of a vascularized scapular bone graft from a supine position. A clinical case is presented to illustrate the operative approach.

METHODS

Twenty cadaveric hemibody specimens were dissected in the supine position. Outcomes of interest included the characterization of anatomical variants and measurements of pedicle length. Specific measurements included distance from the origin of the subscapular artery (at the axillary artery) to the branch point of the angular artery from the thoracodorsal artery or serratus branch and the length of the angular branch proper.

RESULTS

There are five reported anatomic variations regarding the origin of the angular branch of the thoracodorsal artery. In our cadaveric cohort only four known types were seen, and an entirely new variant was encountered. Six cadaveric dissections exhibited a type 3 configuration, six were type 1, four were type 2, three were type 4, and one was a previously unreported variant we termed a type 6, with multiple angular artery branches originating from the posterior branch of the thoracodorsal. The mean distance between the origin of the subscapular artery and the takeoff of the angular branch was 6.3 ± 2.0 cm. The mean length of the angular branch was 3.7 ± 1.4 cm.

CONCLUSIONS

Supine positioning for harvest of a vascularized bone graft obviates the need for an intraoperative position change and allows reconstruction of bone defects in the hand and upper extremity within a single surgical field.

Treatment of Recalcitrant Femoral Shaft Nonunion With Medial Femoral Condyle Pedicled Autograft: Technical Trick

SUMMARY

Nonunited fractures of the femoral shaft and distal femur are usually successfully addressed with stabilization with or without autogenous bone grafting. For the small subset of these problems that prove recalcitrant to front-line treatment, a pedicled medial femoral condyle (MFC) bone flap can provide a source of vascularized autograft with minimal donor site morbidity. The MFC has gained recent widespread adoption as a free vascularized bone transfer, and here, we present a surgical technique and retrospective analysis of patients treated with a pedicled MFC technique. This serves as a useful treatment option for these difficult problems and may be especially helpful in low resource environments or where microsurgical anastomosis is not feasible.

Vascularized Bone Grafts in Orthopaedic Surgery: A Review of Options and Indications

Vascularized bone grafts have demonstrated increased perfusion, structural integrity, and ability to achieve good outcomes in challenging clinical situations when compared with nonvascularized grafts. These grafts may be pedicled or free, and bring perfused, viable bone into areas of impaired healing. Although numerous grafts have been described, a few grafts have demonstrated particular usefulness and versatility. Pedicled grafts from the distal radius, medial femoral condyle, ribs, and fibula have improved outcomes in challenging situations without the need for microsurgery. Free grafts from the fibula and medial femoral condyle/trochlea, although they require microsurgical anastomosis, can be transferred to virtually any site in the body and have expanding indications. The capacity of these grafts to achieve favorable outcomes in difficult cases make them a powerful tool for orthopaedic surgeons to have in their armamentarium.

Free Medial Femoral Condyle Flap for Reconstruction of Scaphoid Nonunion: A Systematic Review

BACKGROUND

 The free medial femoral condyle (MFC) bone flap is an attractive option for reconstruction of scaphoid nonunion utilizing vascularized bone to augment bony healing, especially in cases of failed prior treatment or osteonecrosis. This review aims to determine the role and reliability of the free MFC flap for treatment of scaphoid nonunion.

METHODS

 A search of electronic databases was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Articles examining free MFC bone flaps for treatment of scaphoid nonunion were included for analysis. Outcomes of interest included flap failure, postoperative union rate, time to union, carpal indices, functional outcomes, and complications.

RESULTS

 Twelve articles met the inclusion criteria. A total of 262 patients underwent free MFC flaps for treatment of scaphoid nonunion. The most common site of nonunion was the proximal pole of the scaphoid with 47% of patients receiving prior attempts at operative management. Overall bony union rate was 93.4% with a mean time to union of 15.6 weeks. There were no flap failures reported. Improvements in carpal indices including scapholunate (p < 0.0004), radiolunate (p < 0.004), lateral interscaphoid angles (p < 0.035), and revised carpal ratio height (p < 0.024) were seen postoperatively. Visual analog scale improved postoperatively from 6.5 to 2.3 (p < 0.015). Postoperative complications were observed in 69 cases (26.3%), with 27 patients (10.3%) requiring further operative intervention. However, no major donor or recipient site morbidity was appreciated.

CONCLUSION

 MFC flaps provide a highly versatile and reliable option for reconstruction of scaphoid nonunion with excellent bony union rates and acceptable complication rates. The present literature suggests that MFC reconstruction of scaphoid nonunion restores radiocarpal anatomy and improves wrist function without causing significant donor or recipient site morbidity.

Addressing common orthopaedic calamities with microsurgical solutions

Reconstructive microsurgery has been an essential aspect of orthopaedic surgery and extremity reconstruction since the introduction of the operating microscope in the mid-20^th century. The reconstructive ladder ranges from simple healing by secondary intention to complex procedures such as free tissue transfer and vascularized composite allotransplantation. As orthopaedic surgery has evolved over the past 60 years, so too have the reconstructive microsurgical skills that are often needed to address common orthopaedic surgery problems. In this article, we will discuss a variety of complex orthopaedic surgery scenarios ranging from trauma to infection to tumor resection as well as the spectrum of microsurgical solutions that can aid in their management.

Donor site morbidity after the harvest of microvascular flaps from the medial and lateral femoral condyle region: Objective, radiologic, and patient-reported outcome of a multi-center trial

BACKGROUND

With the experience-based hypothesis of low donor site morbidity (DSM) for free flaps from the distal femur, this cohort study aimed to evaluate the DSM according to objective and reproducible criteria.

METHODS

One hundred and fifty-six patients who had a flap harvest from either the medial or lateral femoral condyle region between 2005 and 2017 were included. A retrospective chart review was performed for all patients. In total, 97 patients were available for a follow-up examination. Outcomes were assessed according to objective (Knee Society Score; Larson Knee Score; OAK Score; 0-100 points), patient-reported (IKDC Score; KOOS Score; 0-100 points), and radiologic criteria (Kellgren and Lawrence Score; MRI Osteoarthritis Knee Score).

RESULTS

The median follow-up time was 1,529 days (range: 248-4,810). The mean Knee Society Score (94.8 ± 10.1), Larson Knee Score (94.5 ± 10.1), and OAK Score (95.5 ± 6.6) showed nearly unimpaired knee function. The overall patient-reported DSM was low (IKDC Score: 86.7 ± 17.4; KOOS Score: 89.3 ± 17.1). Osteochondral (OC) flaps had a significantly higher DSM, regardless of the donor site. Bone flaps did not show any relevant radiologic morbidity in the Kellgren and Lawrence Score. Besides the procedure-associated cartilage lesions at the OC donor sites, MRI Osteoarthritis Knee Score did not show any significant presence of further knee pathologies in the bilateral MRI Scans. The obvious cartilage lesions did not have a relevant impact on the knee function of most patients.

CONCLUSION

The DSM for bone and soft-tissue flaps from the femoral condyle region is negligible. OC flaps are associated with a significantly higher DSM, although a clinically relevant impact on knee function was not evident in the majority of patients.

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.

A Morphometric Analysis of Hamate Autograft for Proximal Scaphoid Reconstruction

Objective  Recently, authors have investigated using the proximal hamate as osteochondral autograft for proximal pole scaphoid reconstruction in the case of nonunion with avascular necrosis. The aim of our study was to analyze the morphology and anatomic fit of the proximal hamate compared with the proximal pole of the scaphoid using cadaveric specimens. Materials and Methods  Ten cadaver specimens (five males and five females) were dissected. Scaphoid and proximal hamate bones were measured by two independent investigators using electronic calipers and radius of curvature gauges. After measurements were determined to have good correlation, the average value of the two observers' measurements were used for further analysis. Sagittal radius of curvature (ROC), coronal ROC, depth, width, and maximum graft length were compared. Results  The average depth of the scaphoid proximal pole was 12.3 mm (standard deviation [SD] = 1.12) compared with 11.3 mm (SD = 1.24) for the proximal hamate ( p  = 0.36). The average width was 7.8 mm (SD = 1.00) in the scaphoids compared with 8.6 (SD = 1.05) in the hamates ( p  = 0.09). There was also no significant difference in the sagittal ROC between hamates (9.1 mm, SD = 1.13) and scaphoids (9.5 mm, SD = 0.84; p  = 0.36). All of these average measurements were within 1 mm. There was a significant difference between the coronal ROC of the hamate (23.4 mm) and scaphoid (21.1 mm) bones in our samples ( p  = 0.03). Females were on average smaller than their males, but there was no significant difference in fit based on sex alone. Conclusion  The proximal pole of the hamate has similar morphology and size as the scaphoid, with similar depth, width, and sagittal ROC. It has potential as an osteochondral autograft for proximal pole scaphoid reconstruction.

Management of Proximal Pole Scaphoid Nonunions: A Critical Analysis Review

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Optimal management of nonunions of the proximal pole of the scaphoid is controversial and dependent on many patient and pathophysiologic considerations.

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If the proximal pole subchondral bone support is sufficient, options include open reduction and internal fixation, either alone or in combination with autologous nonvascularized or vascularized bone graft.

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If the proximal pole is not salvageable, replacement with osteochondral autografts or osteochondral flaps is the only option for reconstruction of the native anatomy.

Corticoperiosteal medial femoral condyle flap for recalcitrant nonunion in ankle and foot: Outcomes and radiological evaluation of donor site morbidity

BACKGROUND

The aim of this study was to evaluate the effectiveness and safety of free corticoperiosteal medial femoral condyle (MFC) flap for ankle, hindfoot and midfoot reconstruction in patients with recalcitrant nonunion.

METHODS

Patients who underwent ankle and foot reconstruction using the MFC flap at our clinic were recruited for assessment of the union rate, time to union and functional outcome. Furthermore, a clinical and radiological examination of the donor knee was performed using both computed tomography and magnetic resonance imaging.

RESULTS

Thirteen patients with a mean follow-up time of 2.5 years were included; 10 of them had a previously failed ankle and foot arthrodesis. Union was achieved in 11 patients in an average time of 10 months after MFC flap surgery. Donor site morbidity was minor with no radiological evidence for soft tissue or bone complication.

CONCLUSION

MFC flaps are a useful and safe reconstructive tool and may be considered after failed ankle and foot arthrodesis.

Iatrogenic Femur Fracture Following Medial Femoral Condyle Flap Harvest

A case of iatrogenic femoral fracture after harvest of a medial femoral condyle flap is presented. The procedure was performed for a recalcitrant nonunion of the clavicle that required a flap of 6 × 1 × 1 cm. The patient suffered a supracondylar fracture at the proximal extent of the flap harvest site 3 weeks after surgery, requiring surgical fixation of the femur.

VEGF Over-Expression by Engineered BMSC Accelerates Functional Perfusion, Improving Tissue Density and In-Growth in Clinical-Size Osteogenic Grafts

The first choice for reconstruction of clinical-size bone defects consists of autologous bone flaps, which often lack the required mechanical strength and cause significant donor-site morbidity. We have previously developed biological substitutes in a rabbit model by combining bone tissue engineering and flap pre-fabrication. However, spontaneous vascularization was insufficient to ensure progenitor survival in the core of the constructs. Here, we hypothesized that increased angiogenic stimulation within constructs by exogenous VEGF can significantly accelerate early vascularization and tissue in-growth. Bone marrow stromal cells from NZW rabbits (rBMSC) were transduced with a retroviral vector to express rabbit VEGF linked to a truncated version of rabbit CD4 as a cell-surface marker. Autologous cells were seeded in clinical-size 5.5 cm³ HA scaffolds wrapped in a panniculus carnosus flap to provide an ample vascular supply, and implanted ectopically. Constructs seeded with VEGF-expressing rBMSC showed significantly increased progenitor survivival, depth of tissue ingrowth and amount of mineralized tissue. Contrast-enhanced MRI after 1 week in vivo showed significantly improved tissue perfusion in the inner layer of the grafts compared to controls. Interestingly, grafts containing VEGF-expressing rBMSC displayed a hierarchically organized functional vascular tree, composed of dense capillary networks in the inner layers connected to large-caliber feeding vessels entering the constructs at the periphery. These data constitute proof of principle that providing sustained VEGF signaling, independently of cells experiencing hypoxia, is effective to drive rapid vascularization and increase early perfusion in clinical-size osteogenic grafts, leading to improved tissue formation deeper in the constructs.

Use of a Free Vascularized Medial Femoral Condyle Flap for Revision Surgery in a Pediatric Patient with Congenital Pseudarthrosis of the Clavicle

The most common surgical treatment for congenital pseudarthrosis of the clavicle (CPC) is resection of the pseudarthrosis, placement of an autologous bone graft, and Kirschner wire or plate fixation. However, in some cases, bone fusion cannot be achieved at the first surgery, and an additional surgery is required. We present a case report of a boy with a right CPC who failed radiographic bone union after the first surgery. He subsequently underwent revision surgery with resection of the pseudarthrosis, plate fixation, and establishment of a vascularized medial femoral condyle (MFC) flap to ensure bone union. Three months after the revision surgery, a radiographic bone union was achieved, and no symptoms were observed for one year after the operation. There have been no previous reports of the use of a vascularized MFC flap as a treatment for CPC. We believe that this technique effectively ensures bone union during revision surgery for CPC.

Vascularized Olecranon Bone Graft: An Anatomical Study and Novel Technique

PURPOSE

Autologous bone grafting is commonly used in reconstructive hand surgery. Various sources of nonvascularized autologous bone grafts have been described in the literature. However, in some situations, a vascularized bone graft may be needed. Popular vascularized bone grafts are taken from the distal radius, iliac crest, and medial femoral condyle. The purpose of this study was to examine the feasibility of harvesting a free vascularized bone flap from the proximal ulna.

METHODS

Latex was injected via the brachial artery to facilitate visualization of perforators in 10 cadaveric specimens. Dissections were performed of the olecranon; all periosteal perforators were noted, and their lengths and diameters recorded. Corticocancellous bone flaps with their supplying pedicles were harvested. Three additional fresh specimens were injected with india ink via the pedicles to demonstrate perfusion of the harvested bone flap.

RESULTS

Consistent vascular anatomy supplied the olecranon. A perforator from the posterior ulnar recurrent artery supplied the proximal ulna and olecranon, from which a vascularized bone flap can be harvested. Branches to the flexor carpi ulnaris muscle may allow chimeric flaps to be harvested. Average pedicle length was 5.8 cm and average pedicle diameter was 2.4 mm. India ink injection of the pedicles showed perfusion of the periosteum as well as intraosseous cancellous bone.

CONCLUSIONS

A vascularized olecranon free flap can be harvested based on the posterior ulnar recurrent artery. Vascular anatomy is consistent and flap harvest is simple and straightforward in all cadaveric specimens.

CLINICAL RELEVANCE

A vascularized olecranon free flap represents a potential new surgical option when vascular bone flap reconstruction is considered.

Medial Femoral Condyle Free Flap Reconstruction of Complex Foot and Ankle Pathology

Background:

Complex hindfoot pathology may benefit from vascularized bone flap reconstruction rather than traditional bone grafting techniques. Medial femoral condyle (MFC) flaps provide vascularized periosteum, skin, and corticocancellous bone.

Methods:

A retrospective, single-institution cohort study of consecutive MFC flaps performed for complicated hindfoot reconstruction between 2013 and 2019 was reviewed. Radiologic follow-up assessed osseous union and clinical outcomes were evaluated with the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score. Thirty MFC flaps were performed in 28 patients for complex hindfoot pathology. Twenty-seven flaps had adequate clinical and radiographic follow-up (mean 15.8 months).

Results:

The majority presented with avascular necrosis (83%) and failed prior operations (67%, mean 3.1). Most hindfoot procedures involved arthrodesis (n = 24, 80%); tibiotalocalcaneal (n = 11) and talonavicular (n = 7) most frequently. Mean osseous flap volume was 10.3 cm3 (range 1.7-18.4 cm3); one flap required takeback for venous congestion but no total flap losses occurred. Primary osseous union was initially achieved in 20 patients (74%, mean 217 days). Six flaps developed interface nonunion; 5 underwent revision arthrodesis and ultimately achieved union in 24/27 flaps (89%, mean 271 days). Risk factors for nonunion were body mass index (BMI) >30 ( P = .017) and prior arthrodesis ( P = .042). Mean AOFAS hindfoot scores increased significantly from 52.3 preoperatively to 70.7 postoperatively ( P < .001). Subscore analysis demonstrated significant improvement in postoperative pain scores from 14.2 to 27.3 out of 40 ( P < .001).

Conclusion:

The MFC free flap provided vascularized bone for complicated foot and ankle reconstruction with relatively low donor site morbidity, promising osseous union results, and improved functional outcomes.

Level of Evidence:

Level IV, retrospective case series.

The Anterolateral Thigh-Medial Femoral Condyle Chimeric Flow-through Flap for Posttraumatic Wrist Arthrodesis

Wrist arthrodesis in the setting of segmental bone loss can have high failure rates. Therefore, vascularized bone grafting has been advocated for select patients. Patients suffering concomitant large soft tissue loss present even greater challenge. To that end, we describe for the first time successful anterolateral thigh-medial femoral condyle chimeric flow-through flap for posttraumatic wrist arthrodesis and soft tissue coverage. This is a case report of a 19-year-old male laborer who suffered a large blast injury resulting in significant bone and soft tissue injury to the dominant right hand and wrist. After multiple debridements, there was a segmental bone defect from the distal radius and ulna to the metacarpal bases, as well as a 12×8 cm dorsal soft tissue defect. This was reconstructed with a anterolateral thigh-medial femoral condyle chimeric flow-through flap and concomitant wrist arthrodesis in a single stage. Besides a donor site thigh seroma, recovery was uneventful with clinical and radiographic evidence of fusion by >9 weeks postoperation.

Long-Term Outcomes of Vascularized Trochlear Flaps for Scaphoid Proximal Pole Reconstruction

Reconstruction of proximal pole scaphoid nonunion using medial femoral trochlea osteochondral free flap is indicated in young active patients for whom salvage procedures are not ideal. This article reviews the outcomes data available in the literature and provides a brief report of clinical, radiographic, and patient-reported outcomes for the subset of our patients with greater than 3 years postoperative follow-up. The present literature suggests that medial femoral trochlea reconstruction for proximal pole scaphoid nonunion can restore radiocarpal anatomy, prevent progressive carpal collapse, improve function, and relieve pain without causing wrist stiffness, weakness, or excessive donor site morbidity in the short and medium term.

Donor site morbidity of vascularized bone grafts from the medial femoral condyle for osseous revascularization

BACKGROUND

Vascularized bone grafts from the medial femoral condyle (MFC) are used to gain surgical revascularization of osseous defects. To date objective data regarding the donor site morbidity are limited. This study aims to evaluate the donor site associated outcome after MFC flap harvest.

PATIENTS AND METHODS

From 2008 to 2016, 22 patients who underwent MFC bone flap harvest for osseous revascularization of 9 talus, 8 scaphoids, 2 metacarpals, 1 phalanx, 1 pilon tibiale, and 1 distal femur were included. Outcome analysis was performed for the whole cohort as well as for two subgroups (recipient site upper [group A] and lower extremity [group B]) by the lower extremity functional scale (LEFS), the OAK-score of the Swiss Orthopedic Society and the visual analog scale (VAS). Additionally, a 3D gait analysis was performed for four patients.

RESULTS

The mean flap size was 1 × 1 × 3 cm. No flap loss was observed. One minor surgical revision was performed due to donor site hematoma. Mean follow-up was 35.8 (12-98) months. Mean LEFS-score was 74.9 ± 9.5 (A: 74.3 ± 7.9; B: 75.6 ± 11.2, p > .05) and OAK-score was 92.8 ± 9.4 (A: 93.2 ± 5.8; B: 92.4 ± 12.3, p > .05). At follow-up examination, pain at rest was stated with 0.1 ± 0.2 (A: 0.1 ± 0.3; B 0 ± 0, p > .05) and with activity 0.6 ± 1.4 (A: 1.2 ± 1.8; B: 0 ± 0, p > .05) on VAS. The 3-D gait analysis showed normative walking patterns.

CONCLUSION

After MFC flap harvest knee function and gait pattern were almost unimpaired. Donor site morbidity can be considered as being of minor concern in the decision-making for this microvascular procedure.