The Role of Vascularized Bone Grafting in Scaphoid Nonunion

Scaphoid Nonunions: Local Vascularized Bone Flaps

If untreated, scaphoid nonunions may progress to scaphoid nonunion advanced collapse in a substantial portion of cases and may require salvage procedures. Multiple different techniques have been described to address scaphoid nonunion. Vascularized bone flaps (VBFs) are associated with faster time to union compared with nonvascularized grafts. Because these are local pedicled flaps, they do not require microsurgical anastomoses and should be within the armamentarium of all hand surgeons. Appropriately chosen local VBFs, can achieve union rates up to 90% to 100% in appropriately selected patients.

Principles and Evaluation of Bony Unions

Nonunion is a common and costly problem. Unfortunately, there is no widely agreed upon and standardized definition for nonunion. The evaluation of bony union should start with a thorough history and physical examination. The clinician should consider patient-dependent as well as patient-independent characteristics that may influence the rate of healing and evaluate the patient for physical examination findings suggestive of bony union and infection. Radiographs and clinical examination can help confirm a diagnosis of union. When the diagnosis is in doubt, however, advanced imaging modalities as well as laboratory studies can help a surgeon determine when further intervention is necessary.

Proximal Hamate Reconstruction of Proximal Pole Scaphoid Nonunion: A Case Series and Analysis of Clinical Outcomes

BACKGROUND

Small proximal pole scaphoid nonunions present a clinical challenge influenced by fragment size, vascular compromise, deforming forces exerted through the scapholunate interosseous ligament (SLIL), and potential articular fragmentation. Osteochondral autograft options for proximal pole reconstruction include the medial femoral trochlea, costochondral rib, or proximal hamate. This study reports the clinical outcomes of patients treated with proximal hamate osteochondral autograft reconstruction.

METHODS

A retrospective review identified patients treated with this surgery from 2 institutions with a minimum 6-month follow-up. Clinical outcomes included the Visual Analog Dcale pain score, 12-item Short-Form survey, abbreviated Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score, wrist and forearm range of motion (ROM), radiographic assessment, and complications. We reviewed and compared these outcomes with those of the current published literature.

RESULTS

Four patients (mean age: 24 years, 75% men) with a 12.8-month average follow-up (range: 6-20 months) were included. Radiographic union was identified in all cases by 12 weeks (range, 10-12). The average wrist ROM was 67.5% flexion/extension and 100% pronation/supination compared with the contralateral side at the final follow-up. The mean QuickDASH score was 17.6 (SD, 13). No complications were identified.

CONCLUSIONS

Proximal pole scaphoid nonunion reconstruction using autologous proximal hamate osteochondral graft demonstrated encouraging clinical and radiographic outcomes. Proximal hamate harvest involves minimal donor site morbidity without a distant operative site, uses an osteochondral graft with similar morphology to the proximal scaphoid, requires no microsurgical technique, and permits reconstruction of the SLIL using the volar capitohamate ligament.

The progress in the classification and treatment of scaphoid nonunion

Scaphoid fracture is the most common carpal fracture, accounting for 50%-80% of all carpal fractures in the Youngers and manual workers. The nonunion rate of scaphoid fractures was approximately 10-15%. Scaphoid nonunion can lead to wrist deformity, wrist collapse, ischemic necrosis, and traumatic osteoarthritis resulting in the loss of wrist function and seriously influence the patients' lives. Achieving bony union is essential for the treatment of scaphoid nonunion. Although many surgical procedures including various forms of bone grafting have been developed to improve bony union, there is no conclusion about which method is the most effective and optimal. In this review, we provide an overview of the diagnostic, classification and progress in the treatments of scaphoid nonunion fractures.

Comparison between Vascular and Non-Vascular Bone Grafting in Scaphoid Nonunion: A Systematic Review

Background: Scaphoid fractures correspond to 60% of all carpal fractures, with a risk of 10% to progress towards non-union. Furthermore, ~3% present avascular necrosis (AVN) of the proximal pole, which is one of the main complications related to the peculiar vascularization of the bone. Scaphoid non-union can be treated with vascularized and non-vascularized bone grafting. The aim of the study is to evaluate the rates of consolidation of scaphoid non-union treated using two types of grafts. Methods: A systematic review of two electronic medical databases was carried out by two independent authors, using the following inclusion criteria: non-union of the proximal pole of the scaphoid bone, treated with vascular bone grafting (VBG) or non-vascular bone grafting (NVBG), with or without the use of internal fixation, patients aged ≥ 10 years old, and a minimum of 12 months follow-up. Research of any level of evidence that reports clinical results and regarding non-union scaphoid, either using vascularized or non-vascularized bone grafting, has been included. Results: A total of 271 articles were identified. At the end of the first screening, 104 eligible articles were selected for the whole reading of the text. Finally, after reading the text and the control of the reference list, we selected 26 articles following the criteria described above. Conclusions: The choice of the VBG depends mainly on the defect of the scaphoid and on the surgeon’s knowledge of the different techniques. Free vascular graft with medial femoral condyle (MFC) seems to be a promising alternative to local vascularized bone grafts in difficult cases.

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.

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.

Treatment of unstable scaphoid waist nonunion with cancellous bone grafts and cannulated screw or Kirschner wire fixation

We compared two methods of fixation for unstable scaphoid waist nonunions regarding rate of scaphoid union, union time, deformity correction, clinical outcomes (pain, range of motion, and grip strength), and QuickDASH scores. Eighty-nine patients who undergo cancellous iliac bone grafting and internal fixation either with a Herbert screw (n = 46) or multiple Kirschner wires (n = 43) were evaluated. The rate of scaphoid union in the K-wire group was 98% (n = 42) versus 89% (n = 41) in the screw group. The mean union time and duration of surgery for K-wire group versus screw group were 12 versus 15 weeks and 45 versus 66 min respectively. There was no significant difference between the two groups with respect to deformity correction, clinical outcomes, and QuickDASH scores. Despite there was no significant difference in the rate of scaphoid union between the two fixation methods, the K-wires procedure had the advantages of short union time, less demanding, and less expensive than the screw implant.

[Comparison of scaphoid reconstruction with a non-vascularised bone graft, with and without shock waves; preliminary results]

BACKGROUND

Focused, high energy shock wave therapy (ESWT) stimulates bone healing by neo-angiogenesis and activating osteocytes. This study investigates if applying an ESWT intraoperatively improves and accelerates the healing of a scaphoid nonunion after reconstruction using a non-vascularized bone graft.

PATIENTS AND METHODS

In this prospective, ongoing study, patients with a scaphoid reconstruction using a non-vascularized bone graft and stabilization for non-union, are randomized for having additionally an intraoperative ESWT (intervention group) or not (control group). In 6 weeks-intervals, patients have a clinical and radiological follow-up, including a CT scan at 12, 18, and if needed 24 weeks postoperatively. The intervention group and the control group are compared with regard to the proportion of the bridged contact area between scaphoid and the bone graft at 12, 18, and 24 weeks postoperatively and the rate of the healed scaphoids at the final follow-up. At time of this data analysis, 35 patients of the intervention group and 33 patients of the control group had passed all of their scheduled follow-ups.

RESULTS

Twenty-four weeks postoperatively, the scaphoids of 27 patients (77 %) in the intervention group and those of 20 patients (61 %) in the control group were healed. At 12, 18, and 24 weeks, the contact area between scaphoid and the bone graft proximally was bridged by 80 %, 84 %, and 86 % respectively in the intervention group, and 74 %, 81 %, and 84 % in the control group. Distal to the bone graft, the gap was bridged by 91 %, 94 %, and 95 % for the intervention group and 77 %, 90 %, and 94 % for the control group. At 12 weeks postoperatively, the proportional healing distal to the bone graft was significantly higher after ESWT.

CONCLUSION

A single, intraoperative ESWT improves the healing rate of scaphoid reconstruction with a non-vascularized bone graft and accelerates the gap bridging during the first 12 weeks after surgery.

[Scaphoid non-union: Experience from more than 280 reconstructions using a medial femur condyle bone graft]

BACKGROUND

Since 2008 we have been using many free vascularized medial femoral condyle grafts for reconstruction of difficult scaphoid non-unions. This article aims to report our results and experiences.

PATIENTS AND METHODS

Until the end of 2019 a total of 287 patients had a microvascular scaphoid reconstruction, 158 with use of a corticocancellous, and 129 using an osseocartilaginous graft. Complete analysis of all of these patients was impossible. This manuscript is based on a retrospective analysis of 28 out of 42 patients with corticocancellous grafts operated on between 2008 and 2010 with a mean follow-up time of 6.1 years as well as another 44 out of 76 patients with an osseocartilaginous graft operated on between 2011 and 2016 with a mean follow-up time of 44 months. Follow-up included clinical parameters, conventional x-rays, a DASH-Score and a modified Mayo wrist score. Additionally, the authors report their personal experiences - necessarily without quantification. In view of this incomplete data-pool statistical analysis was not reasonable.

RESULTS

In the group with corticocancellous reconstructions bony healing was achieved in 69 %, salvage operations were required in 9,5 %. The 28 patients had a mean DASH-Score of 11, a mean modified Mayo wrist score of 83 points, a mean ROM of 86° and a mean grip strength of 89 % of the contralateral side. In the group with osseocartilaginous reconstructions complete bony healing was seen in 80 %, partial healing in 5 %, and salvage procedures were required in 11 %. The remaining 39 patients had a mean DASH-Score of 15, a mean modified Mayo wrist score of 80 points, a mean ROM of 90° and a grip strength of 81 % of the contralateral hand. A specific complication was an ossification of the pedicle, but the main problem was a satisfying reconstruction of the shape of the scaphoid and reestablishment of carpal stability in far advanced cases. We could not identify factors reliable for the persisting non-unions.

CONCLUSIONS

These operations combine great chances for healing with considerable risks for serious complications. So future patients have to be fully informed, so that their decision for such a procedure is based on realistic expectations.

Vascularized bone graft and scapholunate fixation for proximal scaphoid nonunion: a case report

We report a 38-year-old woman with a proximal scaphoid fracture nonunion from an injury 1 year ago. She was successfully treated with 2,3 intercompartmental supraretinacular artery pedicled vascularized bone graft and scapholunate fixation. It highlights the possible combination of scapholunate fixation and vascularized bone grafting in treating proximal scaphoid nonunion.

[Nitinol memory alloy two foot fixator with autologous cancellous bone grafting for old scaphoid fracture and nonunion]

Objective

To summarize the effectiveness of nitinol memory alloy two foot fixator with autologous cancellous bone grafting in treating old scaphoid fracture and nonunion.

Methods

Between January 2013 and January 2017, 11 patients of old scaphoid fracture and nonunion were treated with nitinol memory alloy two foot fixator and autologous cancellous bone grafting. All patients were male with an average age of 26.1 years (range, 18-42 years). The fractures were caused by sport in 3 cases, falling in 7 cases, and a crashing object in 1 case. The interval between injury and operation was 6-18 months (mean, 8.9 months). Postoperative outcome measures included operation time, fracture healing time, grip strength, range of motion (ROM) of flexion, extension, ulnar deviation, and radial deviation, Mayo score, visual analogue scale (VAS) score, and the Disabilities of the Arm, Shoulder, and Hand (DASH) score.

Results

The operation time was 35-63 minutes (mean, 48 minutes). All incisions had primary healing with no infection and loosening or breakage of internal fixator. All patients were followed up 12-30 months (mean, 20.7 months). X-ray films showed that fracture healing was achieved in all patients with an average time of 15 weeks (range, 12-25 weeks). All internal fixators were removed after 10-12 months of operation (mean, 11.2 months). At last follow-up, the grip strength, ROMs of flexion, ulnar deviation, and radial deviation were superior to those before operation ( P<0.05), no significant difference was found in ROM of extension between pre- and post-operation ( t=0.229, P=0.824). There were significant differences in above indexes between affected and normal sides ( P<0.05). At last follow-up, the Mayo, VAS, DASH scores were also significantly superior to those before operation ( P<0.05).

Conclusion

For the old scaphoid fracture and nonunion, Ni-Ti arched shape-memory alloy fixator and autologous cancellous bone grafting can obtain good effectiveness, which is an effective treatment.

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.

Novel Aptamer-Functionalized Nanoparticles Enhances Bone Defect Repair By Improving Stem Cell Recruitment

Background

The restoration and repair method in the clinic of delayed fracture healing and non-union after comminuted fractures are urgently needed to improve the prognosis of patients. The recruitment of endogenous stem cells has been considered a promising approach in bone defect repair.

Propose

The aim of this study was to generate a de novel MSCs aptamer and developed the first, feasible, economical, bio-compatible, and functional MSCs aptamer-directed nanoparticles without complex manufacture to recruit mesenchymal stem cells (MSCs) for bone defect regeneration.

Methods

Whole-cell SELEX was used to generate a de novel MSCs aptamer. Flow cytometry was applied to assess the binding specificities, affinities and sorting abilities of the aptamers. Nano-Aptamer Ball (NAB) was constructed by NHS/EDC reaction. The diameter and zeta of NAB were assessed by dynamic light scattering. CCK8 assay was utilized to evaluate whether NAB could cause non-specific cytotoxicity and induce cell proliferation. To evaluate the bone repair capacity of NAB, histomorphological staining, alizarin red and micro X-ray were used to observe the repair degree of defect in vivo. ELISA was used to detect osteopontin (OPN), osteocalcin (BGP) by, and alkaline phosphatase (ALP) in peripheral blood.

Results

MSCs aptamer termed as HM69 could bind with MSCs with high specificity and Kd of 9.67 nM, while has minimal cross-reactivities to other negative cells. HM69 could capture MSCs with a purity of >89%. In vitro, NAB could bind and capture MSCs effectively, whereas did not cause obvious cytotoxicity. In vivo, serum OPN, BGP, and ALP levels in the NAB group of rats were increased at both 2 and 4 weeks, indicating the repair and osteogenesis generation. The healing of bone defects in the NAB group was significantly better than control groups, the defects became blurred, and local trabecular bone growth could be observed in X-ray. The organized hematoma and cell growth in the bone marrow of the NAB group were more vigorous in bone sections staining.

Conclusion

These suggested that HM69 and HM69-functionalized nanoparticles NAB exhibited the ability to recruit MSCs both in vitro and in vivo and achieved a better outcome of bone defect repair in a rat model. The findings demonstrate a promising strategy of using aptamer-functionalized bio-nanoparticles for the restoration of bone defects via aptamer-introduced homing of MSCs.