AVN is a relatively common complication of scaphoid fracture, which is mostly due to the specific anatomy and vasculature of this particular carpal bone. AVN often results in impaired union, and despite the recently developed methods for correction of scaphoid fracture, nonunion occurs as frequently as 10%. Failure of treatment in the case of nonunion can lead to chronic pain and progressive osteoarthritis of the wrist 10. In such instances, the therapeutic goal is to stabilize the wrist by promoting scaphoid union. VBG is a promising therapeutic intervention in the presence of AVN 8.
The surgical technique proposed by Mathoulin is based on combined transplantation of bone and vasculature, the latter of which is particularly important for preventing AVN, which occurs due to disruption of blood supply 7. Consistently, the results of our clinical trial indicated that the Mathoulin method can be quite effective in the treatment of nonunion scaphoid fracture with proximal AVN. A meta-analysis in 2016 by Ferguson et al. reported union rates of 74 and 62 percent for vascularized and non-vascularized bone grafts in the surgical fixation of scaphoid fracture 11, further confirming the promising clinical outcome that can be achieved by vascularization 12.
As of recent, in 2022, two clinical investigations on scaphoid fracture were published. The first, by Polat et al., was conducted on 39 patients with proximal scaphoid nonunion, suggesting distal radial bone graft based on intercompartmental supraretinacular artery pedicle as a suitable method for fixation of scaphoid fracture, with a mean duration of 100 min and a union rate of 90% 13. The other study, led by Ecker et al., reported 29 successful iliac crest cancellous bone grafts in 30 patients with scaphoid nonunion 14. Consistent with these findings, we achieved a union rate of 97.29% with our patients.
In 2021, several studies were published on the efficacy of VBG in scaphoid fractures with AVN. Çolak et al. demonstrated a union rate of 81% for 68 patients with scaphoid nonunion treated with VBG 15. Lamon et al. explored 42 cases with scaphoid nonunion of the proximal and middle third without SNAC, reporting a union rate of 83%, significantly improved wrist function and markedly decreased pain intensity following arthroscopic bone grafting 16. Another study by Saruhan et al. on 4 patients with proximal scaphoid nonunion and AVN reported a union rate of 100%, significant decrease in pain and moderate objective functional results after surgical fixation with hamate bone autograft 17. Papatheodorou et al. treated 64 patients with established proximal scaphoid nonunion and AVN by means of vascularized distal radius graft, observing a union rate of 86% and markedly improved wrist function within a mean interval of 12 weeks 18. For their investigation, Cavit et al. enrolled 17 male patients with scaphoid waist and proximal pole fracture, 13 of whom had AVN. After performing intercompartmental supraretinacular artery vascularized graft and compression screw fixation, union was achieved in 88.2% of cases. Similarly, a significant improvement in MMWS and carpal extension was attained 19. In the present investigation, our patients displayed significant improvements in their MMWS over the span of 9 months, and a considerably sharp decline in pain intensity, following Mathoulin surgical intervention.
A year earlier, in 2020, Kawasaki et al. incorporated vascularized bone grafting for the fixation of scaphoid nonunion with AVN in 11 patients. Union was achieved in 10 patients, with a mean MMWS of 88 (range, 75–100 points) 20. Although, we did not attain a mean MMWS as high as 88 in our study, the increase in MMWS within the span of three months from surgery was still considerable.
A retrospective clinical study by Ammori et al. in 2019 on 806 patients with scaphoid fracture revealed a union rate of 69% independent of the type of bone graft – vascularized or non-vascularized – along with a 22% prevalence of nonunion even after surgical correction 21.
Two major studies on scaphoid fractures, in 2018, reported noteworthy findings. Rahimnia et al. achieved a union rate of 73% with 41 patients who were treated with VBG for scaphoid nonunion. Postoperative union was accompanied with significant improvement in MMWS and scaphoid length 22. Sander et al. investigated a total of 16 patients with scaphoid fracture divided into two groups based on the technique of surgery, reporting a higher MMWS for the group having been treated with bone graft compared with patients who had only received headless compression screws (HCS) 23.
Consistent with the more recently published literature, Wolf et al. in 2014 reported similar findings they had observed with 28 cases of scaphoid nonunion, 75% of whom achieved union, which was characterized by improved grip strength, range of motion and MMWS 24. Similarly, our participants exhibited significantly improved wrist function in terms of flexion, extension, supination and pronation.
As we demonstrated in this study, the Mathoulin method of fixation negatively regulated postoperative pain, and improved the hand muscle force and movements.
Limitations
Orthopaedic surgeons are encouraged to identify novel and practical methods for preventing development of AVN after scaphoid fracture, which is a relatively common complication in the case of this carpal bone. Based on our findings, implantation of vascular grafts along with bone graft, as practiced through the Mathoulin method of surgical fixation, proves to be an effective type of intervention for prevention of postoperative AVN and pain in scaphoid waist nonunion, and enhancing carpal function and grip strength. However, further clinical investigations are warranted to confirm our experimental results, as the scope of the present study was limited in its own right.