Vascularized bone grafts and their applications in the treatment of carpal pathology

Treatment of AVN-Induced Proximal Pole Scaphoid Nonunion Using a Fifth and Fourth Extensor Compartmental Artery as a Vascularized Pedicle Bone Graft: A Retrospective Case Series

BACKGROUND Scaphoid nonunion (SN) is a challenging condition in wrist pathology, often resulting in severe consequences if left untreated. Surgical intervention, particularly using vascularized bone grafts (VBGs), is a promising but uncertain approach. The 4+5 extensor compartment artery (ECA) pedicled graft, less commonly used for SN, has potential benefits due to its vascular supply and accessibility to the scaphoid. This study aimed to evaluate the effectiveness of the 4+5 ECA pedicled graft combined with headless compression screw fixation in treating avascular necrosis (AVN)-induced proximal pole SN. Radiological results, functional outcomes, and complications related to this method were assessed. MATERIAL AND METHODS This was a retrospective analysis of 19 proximal pole SN cases with AVN treated using the 4+5 ECA-VBG technique from 2016 to 2022. Patients underwent preoperative evaluation and postoperative follow-up for at least 1 year. Data on surgery, demographics, radiological assessments, and functional outcomes were recorded and analyzed statistically. RESULTS All patients achieved radiographic union within 8.5 weeks postoperatively, with revascularization of proximal pole necrosis. Significant improvements in functional outcomes were observed, including pain reduction, increased wrist range of motion, improved grip and pinch strength, and enhanced wrist scores. No major complications were reported. CONCLUSIONS The 4+5 ECA-VBG technique, with headless compression screw fixation, showed high success rates in treating AVN-induced proximal pole SN. This method offers comprehensive restoration of wrist function and minimal complications, making it a viable option for SN management, especially in AVN cases. Further research is needed to confirm these results and establish standardized protocols for SN treatment.

A Comprehensive Review of Treatment Strategies for Early Avascular Necrosis

Avascular necrosis (AVN), characterised by compromised blood supply leading to bone necrosis, poses a significant challenge in orthopaedic and rheumatologic practice. This review comprehensively examines early AVN treatment strategies, including aetiology and risk factors, clinical presentation, conservative and surgical approaches, emerging therapies, and rehabilitation. Key findings underscore the importance of early detection, personalised treatment plans, and a multidisciplinary approach involving orthopaedic specialists, rheumatologists, and physical therapists. The implications for clinical practice emphasise individualised care, staying abreast of emerging therapies, and patient education. Recommendations for future management strategies highlight the need for imaging technology advancements, regenerative therapies integration, and ongoing research into genetic and molecular pathways. As the field continues to evolve, translating research findings into clinical practice holds promise for improving outcomes and enhancing the overall quality of life for individuals affected by AVN.

A composite, off-the-shelf osteoinductive material for large, vascularized bone flap prefabrication

We previously described an immortalized, genetically-engineered human Mesenchymal stromal cell line to generate BMP2-enriched Chondrogenic Matrices (MB-CM), which after devitalization and storage could efficiently induce ectopic bone tissue by endochondral ossification. In order to increase the efficiency of MB-CM utilization towards engineering scaled-up bone structures, here we hypothesized that MB-CM can retain osteoinductive properties when combined with an osteoconductive material. We first tested different volumetric ratios of MB-CM:SmartBone® (as clinically used, osteoconductive reference material) and assessed the bone formation capacity of the resulting composites following ectopic mouse implantation. After 8 weeks, as little as 25% of MB-CM was sufficient to induce bone formation and fusion across SmartBone® granules, generating large interconnected bony structures. The same composite percentage was then further assessed in a scaled-up model, namely within an axially-vascularized, confined, ectopically prefabricated flap (0.8 cm³) in rats. The material efficiently induced the formation of new bone (31% of the cross-sectional area after 8 weeks), including bone marrow and vascular elements, throughout the flap volume. Our findings outline a strategy for efficient use of MB-CM as part of a composite material, thereby reducing the amount required to fill large spaces and enabling utilization in critically sized grafts, to address challenging clinical scenarios in bone reconstruction. STATEMENT OF SIGNIFICANCE: Most bone repair strategies rely either on osteconductive properties of ceramics and devitalized bone, or osteoinductive properties of growth factors and extracellular matrices (ECM). Here we designed a composite material made of a clinically accepted osteoconductive material and an off-the-shelf tissue engineered human cartilage ECM with strong osteoinductive properties. We showed that low amount of osteoinductive ECM potentiated host cells recruitment to form large vascularized bone structures in two different animal models, one being a challenging prefabricated bone-flap model targeting challenging clinical bone repair. Overall, this study highlights the use of a promising human off-the-shelf material for accelerated healing towards clinical applications.

A systematic review on the management of idiopathic avascular necrosis of the scaphoid (Preiser's disease)

BACKGROUND

Treatment options for patients with Preiser's disease are challenging and varied. This article thus provides a systematic review of existing studies on the outcomes of the treatments for patients suffering from Preiser's disease in order to investigate the most appropriate management of Preiser's in each stage of the disease.

METHODS

We followed PRISMA guidelines while performing the study, and reviewed 107 papers in all languages from 1981 till November 2020 and included 42 studies that met the eligibility criterion. Studies investigating the outcome of one or more treatment options for Preiser's disease were eligible. Besides, quantitative analysis on 130 individuals (135 wrists) of the included studies was performed.

RESULTS

The results show that in stages II and III, pain score reduces more in surgical approach than in conservative treatment. In stage II of the Preiser's, Vascularized Bone Grafting (VBG) was more effective in pain alleviation and improvement in wrist range of motion (ROM) and Mayo Modified Wrist Score (MMWS) than immobilization. Proximal Row Carpectomy (PRC) in stage III causes more pain relief and ROM improvement than VBG and conservative treatments like prescribing NSAIDs. Inconsistent evidence was found in case studies of stage IV; however, they generally favour PRC and SILASTIC implants. Surgical studies of stage I are not yet enough for making a conclusive assessment.

CONCLUSION

Surgical treatment outcomes seem more satisfactory in all Preiser's disease stages. Specifically, VBG for patients of stage II provided they have no scaphoid degenerative changes, and PRC seems more satisfactory for stage III.

LEVEL OF EVIDENCE

IV; systematic review of case reports and case series on Preiser's disease.

A review of biomimetic scaffolds for bone regeneration: Toward a cell-free strategy

In clinical terms, bone grafting currently involves the application of autogenous, allogeneic, or xenogeneic bone grafts, as well as natural or artificially synthesized materials, such as polymers, bioceramics, and other composites. Many of these are associated with limitations. The ideal scaffold for bone tissue engineering should provide mechanical support while promoting osteogenesis, osteoconduction, and even osteoinduction. There are various structural complications and engineering difficulties to be considered. Here, we describe the biomimetic possibilities of the modification of natural or synthetic materials through physical and chemical design to facilitate bone tissue repair. This review summarizes recent progresses in the strategies for constructing biomimetic scaffolds, including ion-functionalized scaffolds, decellularized extracellular matrix scaffolds, and micro- and nano-scale biomimetic scaffold structures, as well as reactive scaffolds induced by physical factors, and other acellular scaffolds. The fabrication techniques for these scaffolds, along with current strategies in clinical bone repair, are described. The developments in each category are discussed in terms of the connection between the scaffold materials and tissue repair, as well as the interactions with endogenous cells. As the advances in bone tissue engineering move toward application in the clinical setting, the demonstration of the therapeutic efficacy of these novel scaffold designs is critical.

A vascularized bone graft harvested from the dorsal base of the third metacarpal bone for the treatment of scaphoid nonunion

The purpose of this retrospective study was to introduce the use of an alternative vascularized bone graft for treating scaphoid non-union. The vascularized bone graft was harvested from the dorsal base of the third metacarpal bone. From May 2014 to September 2017, 29 patients with scaphoid non-union were treated. Grip and pinch strengths were compared to the contralateral side. The patients rated wrist joint pain on a visual analogue scale. Wrist function was assessed on Mayo Wrist Score. p < 0.05 was considered statistically significant. 18 scaphoids healed at 6 weeks and the other 11 at 16 weeks. Follow-up ranged from 28 to 73 months, for a mean 48 months. At final follow-up, mean wrist flexion had improved from 65° (range, 51°-81°) preoperatively to 72° (range, 61-78°) (p > 0.05), for a contralateral value of 74° (range, 65°-86°). Mean extension had improved from 56° (range, 44°-72°) to 60° (range, 47°-76°) (p > 0.05) for a contralateral value of 66° (range, 52°-80°). Mean wrist pain improved from 4 (range, 3-8) to 2 (range, 0-4) (p < 0.05). Mean pinch strength improved from 6.4 kg (range, 5.2-7.3 kg) to 8.6 kg (6.1-9.9 kg) (p < 0.05). Mayo Wrist Score improved from 49 (range, 10-65) to 92 (range, 70-100) (p < 0.05). Transferring a vascularized bone graft harvested from the base of the third metacarpal bone was an effective alternative for the treatment of scaphoid non-union, achieving bone healing and normal wrist function without significant donor-site morbidity. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Reconstruction of Large Skeletal Defects: Current Clinical Therapeutic Strategies and Future Directions Using 3D Printing

The healing of bone fractures is a well-orchestrated physiological process involving multiple cell types and signaling molecules interacting at the fracture site to replace and repair bone tissue without scar formation. However, when the lesion is too large, normal healing is compromised. These so-called non-union bone fractures, mostly arising due to trauma, tumor resection or disease, represent a major therapeutic challenge for orthopedic and reconstructive surgeons. In this review, we firstly present the current commonly employed surgical strategies comprising auto-, allo-, and xenograft transplantations, as well as synthetic biomaterials. Further to this, we discuss the multiple factors influencing the effectiveness of the reconstructive therapy. One essential parameter is adequate vascularization that ensures the vitality of the bone grafts thereby supporting the regeneration process, however deficient vascularization presents a frequently encountered problem in current management strategies. To address this challenge, vascularized bone grafts, including free or pedicled fibula flaps, or in situ approaches using the Masquelet induced membrane, or the patient’s body as a bioreactor, comprise feasible alternatives. Finally, we highlight future directions and novel strategies such as 3D printing and bioprinting which could overcome some of the current challenges in the field of bone defect reconstruction, with the benefit of fabricating personalized and vascularized scaffolds.

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.

Volar Radius Vascularized Bone Flaps for the Treatment of Scaphoid Nonunion

Vascularized bone flaps (VBFs) improve union rates for scaphoid nonunions compared with nonvascularized grafts. Volar VBFs are indicated in cases of scaphoid nonunion with avascular necrosis and/or humpback deformity. Four volar VBFs are described in this article. The volar carpal artery and pronator quadratus VBFs are most commonly used. The pisiform VBF can be used for replacement of the proximal pole of the scaphoid; it is covered by articular cartilage. The ulna VBF has greater donor morbidity; the ulnar artery is harvested and a palpable donor site deformity results.

The Efficacy of Vascularized Bone Grafts in the Treatment of Scaphoid Nonunions and Kienbock Disease: A Systematic Review in 917 Patients

Background Vascularized bone grafts have become one of the first treatment options for scaphoid nonunions and Kienböck's disease. The aim of this study is to review the current body of the literature regarding the use of four vascularized bone grafts (1,2 ICSRA [1,2 intercompartmental supraretinacular artery] graft, 4+5 ECA [4+5 extracompartmental artery] graft, volar radial graft, and free medial femoral condyle graft) in these pathologies. Patients and Methods A search on MEDLINE and Google Scholar was performed. Exclusion criteria included language other than English, studies with no full text available, case reports, letters, editorials, and review articles. The primary outcomes included consolidation rate of the grafts and time to union regarding scaphoid nonunion, as well as the clinical outcomes (pain, grip strength, range of motion), revascularization of the lunate, and progression of the disease regarding Kienböck's disease. Results A total of 37 articles were included in the study enrolling 917 patients. Regarding scaphoid nonunion, the consolidation rate was 86.3% for the 1,2 ICSRA graft, 93.9% for the volar radial bone graft, and 88.8% for the free medial femoral condyle graft. In patients with Kienböck's disease, progression of the disease was observed in 13% of patients, and grip strength and pain were substantially improved whereas range of motion did not demonstrate statistically significant improvement ( p < 0.05). Conclusion Vascularized bone grafts yield successful outcomes in patients with scaphoid nonunions demonstrating a high union rate. In patients with Kienböck's disease, vascularized grafts lead to revascularization of the lunate in most of the cases with concomitant improvement of the clinical parameters.

Dorsal Distraction Plating and Lunate Decortication for Stage III Kienböck Disease: A Novel Technique

Kienböck disease (KD) is a progressive condition and difficult to manage. A number of treatment algorithms exist but there is no clear consensus as to which method produces the best outcome, particularly for Lichtman stage III disease. The majority of the current treatment options for KD emphasize lunate unloading and restoration of biology with bone graft. However, less attention has been given to the protection of the lunate during revascularization process. We report a novel technique of lunate decompression and bone grafting, combined with wrist distraction with or without radial shortening osteotomy via dorsal wrist bridge plating for the treatment of stage II-IIIa/b KD. This technique provides the advantages of distraction of the carpus unloading the lunate after bone grafting and during revascularization without the issues inherent to external fixation. In addition, this technique allows compression through a radial osteotomy site when performed. Our approach to the treatment of KD has incorporated this technique for patients with stage II or IIIa/b disease.

Scaphoid Nonunion With Poor Prognostic Factors: The Role of the Free Medial Femoral Condyle Vascularized Bone Graft

Background: To report on the results of free medial femoral condyle (MFC) vascularized bone graft for scaphoid nonunions with 1 or more poor prognostic factors. Methods: We have used the free MFC vascularized bone graft for scaphoid nonunions that have 1 or more factors associated with a poor prognosis. These were, a delay in presentation of over 5 years, a proximal pole nonunion, the presence of avascular necrosis (AVN), or previous nonunion surgery. We used this technique on 20 patients over a 4.5-year period. Results: Our overall union rate was 88.5% (17 of 19 patients), with 1 patient failing to attend for follow-up. Our mean union time was 7 months (2-18). All patients had at least 1 poor prognostic factor and over half had 2 or more. Of those with AVN with or without other factors, the union rate was 85% (11 of 13). There were 2 donor site complications that required a further procedure and 2 patients with residual wrist pain that required a scapho-trapezio-trapezoid joint fusion and a radial styloidectomy, respectively. Both nonunions were offered further surgery, and 1 elected to undergo successful revision surgery. Conclusions: Overall, this technique showed good results, in a subgroup of patients that typically have poorer outcomes, with a low incidence of donor site morbidity. Our union rate compares favorably with other techniques for this difficult subset of patients with 1 or more poor prognostic factors, although results are clearly not as good as those of studies using the MFC graft for all scaphoid nonunions. We continue to reserve this technique for nonunions with 1 or more poor prognostic factors, and we believe that this technique should at least be considered in these patients.

Endochondral Priming: A Developmental Engineering Strategy for Bone Tissue Regeneration

Tissue engineering and regenerative medicine have significant potential to treat bone pathologies by exploiting the capacity for bone progenitors to grow and produce tissue constituents under specific biochemical and physical conditions. However, conventional tissue engineering approaches, which combine stem cells with biomaterial scaffolds, are limited as the constructs often degrade, due to a lack of vascularization, and lack the mechanical integrity to fulfill load bearing functions, and as such are not yet widely used for clinical treatment of large bone defects. Recent studies have proposed that in vitro tissue engineering approaches should strive to simulate in vivo bone developmental processes and, thereby, imitate natural factors governing cell differentiation and matrix production, following the paradigm recently defined as "developmental engineering." Although developmental engineering strategies have been recently developed that mimic specific aspects of the endochondral ossification bone formation process, these findings are not widely understood. Moreover, a critical comparison of these approaches to standard biomaterial-based bone tissue engineering has not yet been undertaken. For that reason, this article presents noteworthy experimental findings from researchers focusing on developing an endochondral-based developmental engineering strategy for bone tissue regeneration. These studies have established that in vitro approaches, which mimic certain aspects of the endochondral ossification process, namely the formation of the cartilage template and the vascularization of the cartilage template, can promote mineralization and vascularization to a certain extent both in vitro and in vivo. Finally, this article outlines specific experimental challenges that must be overcome to further exploit the biology of endochondral ossification and provide a tissue engineering construct for clinical treatment of large bone/nonunion defects and obviate the need for bone tissue graft.

[Scaphoid pseudarthrosis : Indications for avascular iliac crest or radius bone grafts]

BACKGROUND

Operative treatment of the scaphoid nonunion includes avascular corticocancellous and cancellous bone grafts and increasingly the use of vascular pedicled and free vascular corticocancellous grafts. Especially the latter require a fair amount of operative expertise and experience in microsurgical techniques.

OBJECTIVE

Which criteria lead to the decision for or against an avascular graft used for reconstruction of scaphoid nonunion? Is our current classification system of a scaphoid pseudarthrosis able to illustrate our diagnostic potential in a way that makes us refer to operative procedures?

METHODS

Evaluation of current literature and expert opinions RESULTS: Avascular bone grafts show a high union rate as long as a sufficient vascularisation of the remaining fragments is present. In general, patients benefit from a very good functional outcome. Even revisions of failed scaphoid union may be successfully treated with an avascular bone graft. Failures of union are repeatedly experienced in treating proximal pole fractures with critical vascularisation or extensive bone loss, especially including avascular necrosis of the proximal pole (AVN). Current classification systems do not allow description and correlation of morphologic findings so as to compare results profoundly and to recommend specific procedures.

CONCLUSIONS

As long as sufficient vascularisation of remaining fragments is seen, the avascular bone graft is eligible for reconstructing scaphoid nonunion. Classification systems do not seem to reflect the status quo of diagnostic possibilities and make it difficult to provide guidelines for state-of-the-art operative procedures.

Vascularized medial femoral condyle graft for management of scaphoid non-union

The purpose of this study was to assess the results of the management of difficult scaphoid non-unions using a vascularized medial femoral condyle graft. We operated on 30 patients with necrosis of the proximal pole or with severe humpback deformity or who presented with persistent non-union despite previous surgery. Twenty-four cases in our series showed full consolidation and six cases showed persistent non-union. The free vascularized medial femoral condyle bone graft can provide not only structural support, but also a consistent and good blood supply that results in excellent rates of union. Level of evidence: IV.

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.

Bone regenerative medicine: classic options, novel strategies, and future directions

This review analyzes the literature of bone grafts and introduces tissue engineering as a strategy in this field of orthopedic surgery. We evaluated articles concerning bone grafts; analyzed characteristics, advantages, and limitations of the grafts; and provided explanations about bone-tissue engineering technologies. Many bone grafting materials are available to enhance bone healing and regeneration, from bone autografts to graft substitutes; they can be used alone or in combination. Autografts are the gold standard for this purpose, since they provide osteogenic cells, osteoinductive growth factors, and an osteoconductive scaffold, all essential for new bone growth. Autografts carry the limitations of morbidity at the harvesting site and limited availability. Allografts and xenografts carry the risk of disease transmission and rejection. Tissue engineering is a new and developing option that had been introduced to reduce limitations of bone grafts and improve the healing processes of the bone fractures and defects. The combined use of scaffolds, healing promoting factors, together with gene therapy, and, more recently, three-dimensional printing of tissue-engineered constructs may open new insights in the near future.

Bone regenerative medicine: classic options, novel strategies, and future directions

This review analyzes the literature of bone grafts and introduces tissue engineering as a strategy in this field of orthopedic surgery. We evaluated articles concerning bone grafts; analyzed characteristics, advantages, and limitations of the grafts; and provided explanations about bone-tissue engineering technologies. Many bone grafting materials are available to enhance bone healing and regeneration, from bone autografts to graft substitutes; they can be used alone or in combination. Autografts are the gold standard for this purpose, since they provide osteogenic cells, osteoinductive growth factors, and an osteoconductive scaffold, all essential for new bone growth. Autografts carry the limitations of morbidity at the harvesting site and limited availability. Allografts and xenografts carry the risk of disease transmission and rejection. Tissue engineering is a new and developing option that had been introduced to reduce limitations of bone grafts and improve the healing processes of the bone fractures and defects. The combined use of scaffolds, healing promoting factors, together with gene therapy, and, more recently, three-dimensional printing of tissue-engineered constructs may open new insights in the near future.

Dorsal vascularized grafting for scaphoid nonunion: a comparison of two surgical techniques

OBJECTIVES

To compare the radiographic and functional outcomes of 2 surgical techniques for treating scaphoid nonunion.

DESIGN

Randomized prospective study.

PATIENTS/PARTICIPANTS

Researchers assessed the outcomes every 2 weeks until bone healing and at discharge.

INTERVENTIONS

(1) Vascularized bone grafting (VBG) using the 1, 2 intercompartmental suprareticular artery and (2) a distal radius nonvascularized bone graft.

MAIN OUTCOMES/INTERVENTIONS

Time to union (primary), union rate, and functional outcomes.

RESULTS

Seventy-five patients were followed for 29 months; 2 were lost to final follow-up. Both groups had similar baseline characteristics. The VBG group reached bone union earlier by 12 days (P = 0.002), but union rates were similar (P = 0.312). There was also less ulnar deviation in the VBG group (P = 0.03). There were no other differences between either intervention groups.

CONCLUSIONS

Although the VBG group attained earlier union, this may not be clinically meaningful, nor justify the greater technical difficulty and use of resources associated with this intervention.

LEVEL OF EVIDENCE

Therapeutic Level II. See instructions for authors for a complete description of levels of evidence.

Vascularized medial femoral trochlea osteocartilaginous flap reconstruction of proximal pole scaphoid nonunions

PURPOSE

The descending geniculate artery's branching pattern includes periosteal vessels supplying the cartilage-bearing trochlea of the medial patellofemoral joint. Previous cadaveric studies described anatomic similarities between the greater curvature of the proximal scaphoid and the convex surface of the medial femoral trochlea (MFT). We describe the technique and report our first 16 consecutive cases of vascularized osteocartilaginous arthroplasty for chronic scaphoid proximal pole nonunions using the MFT, with a minimum of 6 months of follow-up.

METHODS

Chart reviews of 16 consecutive cases of osteocartilaginous MFT flap transfers for scaphoid reconstruction were performed at 2 institutions. Follow-up data were recorded at a minimum of 6 months, with an average of 14 months (range, 6-72 mo). Patient age and sex, duration of nonunion, number of previous surgical procedures, surgical technique, achievement of osseous union, preoperative and postoperative scapholunate angles, preoperative and postoperative range of motion, and pain relief were recorded.

RESULTS

Computed tomography imaging confirmed healing in 15 of 16 reconstructed scaphoids. Mean patient age was 30 years (range, 18-47 y). The average number of previous surgical procedures was 1 (range, 0-3). All patients experienced some wrist pain improvement (12/16 complete relief, 4/16 incomplete relief). Wrist range of motion at follow-up averaged 46° extension (range, 28° to 80°) and 44° flexion (range, 10° to 80°), which was similar to preoperative measurements (average 46° extension and 43° flexion). Scapholunate relationship remained unchanged with average scapholunate angles of 52° before surgery and 49° after surgery.

CONCLUSIONS

Osteochondral vascularized MFT flaps provide a reliable means of achieving resolution of difficult proximal pole scaphoid nonunions. These flaps allow resection of the proximal portion of the unhealed scaphoid and reconstruction with an anatomically analogous convex segment of cartilage-bearing bone. This technique provides the advantages of vascularized bone and ease of fixation. Early follow-up demonstrates a high rate of union with acceptable motion and pain relief.

CLINICAL RELEVANCE

Early follow-up suggests that the vascularized MFT osteocartilaginous flap is a valuable tool for treating challenging proximal pole scaphoid nonunions.

Vascularized bone grafts for the treatment of carpal bone pathology

Primary bone healing fails to occur in 5-15 % of scaphoid bones that undergo fracture fixation. Untreated, occult fractures result in nonunion up to 12 % of the time. Conventional bone grafting is the accepted management in the treatment algorithm of scaphoid nonunion if the proximal pole is vascularized. Osteonecrosis of the proximal scaphoid pole intuitively suggests a need for transfer of the vascularized bone to the nonunion site. Scaphoid nonunion treatment aims to prevent biological and mechanical subsidence of the involved bone, destabilization of the carpus, and early degenerative changes associated with scaphoid nonunion advanced collapse. Pedicled distal radius and free vascularized bone grafts (VBGs) offer hand surgeons an alternative treatment option in the management of carpal bone nonunion. VBGs are also indicated in the treatment of avascular necrosis of the scaphoid (Preiser's disease), lunate (Kienböck's disease), and capitate. Relative contraindications to pedicled dorsal radius vascularized bone grafting include humpback deformity, carpal instability, or collapse. The free medial femoral condyle bone graft has offered a novel treatment option for the humpback deformity to restore geometry of the carpus, otherwise not provided by pedicled grafts. In general, VBGs are contraindicated in the setting of a carpal bone without an intact cartilaginous shell, in advanced carpal collapse with degenerative changes, and in attempts to salvage small or collapsed bone fragments. Wrist salvage procedures are generally accepted as the more definitive treatment option under such circumstances. This manuscript offers a current review of the techniques and outcomes of VBGs to the carpal bones.

Kienböck disease

Kienböck disease, or osteonecrosis of the lunate, is a progressive disease process that can lead to wrist pain and dysfunction. Although it was described over 100 years ago, and advances have been made in understanding this disease, the precise etiology remains uncertain. Anatomic, mechanical, vascular, and traumatic factors have been suggested to contribute to the disease. The natural history is unknown, and radiographic and clinical findings do not always correlate. Progress has been made in recognizing the progression of the avascular process and its deleterious effects on wrist mechanics. Initial treatment is nonsurgical, and it remains unclear whether surgical intervention results in improved outcomes over nonoperative treatment. Traditional surgical procedures such as radial shortening osteotomy and proximal row carpectomy have been shown to be reliable treatment options for relieving pain and improving function. Newer procedures such as pedicled bone grafts from the distal radius may improve direct revascularization of the lunate in earlier stages of the disease, potentially arresting the progression of collapse. Additional data are necessary to determine with certainty whether this type of procedure represents an improvement over the traditional treatment alternatives. Kienböck disease remains a challenging problem for hand surgeons.

Use of the medial femoral condyle vascularized bone flap in traumatic avascular necrosis of the navicular: a case report

The medial femoral condyle vascularized bone flap has a high success rate in published literature regarding its use in nonunions and avascular necrosis of the upper and lower extremities. It is reported to have minimal donor site morbidity and the ability to provide structural support and torsional strength to load-bearing areas. The flap has found particular success in the treatment of scaphoid nonunions. The tarsal navicular, similar to the scaphoid, is largely articular cancellous bone with little surface area for vascular inflow. These anatomic features make the navicular prone to nonunion and avascular necrosis in traumatic scenarios. We describe a case of nonunion and avascular necrosis of the tarsal navicular occurring as sequelae of a high-impact midfoot injury sustained in an automobile accident. After an initial attempt at open reduction and internal fixation with midfoot bridge plating, subsidence and nonunion resulted. An attempt at arthrodesis of the talonavicular and naviculocuneiform joints was then undertaken. This too failed, leading to the development of additional collapse and avascular necrosis. The site was treated with a medial femoral condyle vascularized bone flap. In this single case, the patient returned to pain-free ambulation and reported excellent outcomes and functional capacity. Although we present a successful case, a larger case series is necessary to establish the use of this flap as a reliable option for the treatment of nonunion and avascular necrosis of the tarsal navicular.