Freies gefäßgestieltes Femurknochentransplantat bei Skaphoidpseudarthrose

Pedicled vascularized versus non-vascularized bone grafts in the treatment of scaphoid non-union: a meta-analysis of comparative studies

BACKGROUND

Whether pedicled vascularized bone grafts (PVBGs) are beneficial over non-vascularized bone grafts (NVBGs) still remains controversial. The aim of this study was to compare the clinical results of PVBGs and NVBGs for the treatment of scaphoid non-union.

METHODS

We conducted a meta-analysis of the published studies comparing outcomes of these two different surgical techniques for scaphoid non-union. Outcomes of union rate, time to union, functional results and re-operation rate were analysed.

RESULTS

Seven studies including four randomized controlled studies and three retrospective comparative studies with 413 participants were identified fitting inclusion criteria. Meta-analysis showed that (i) union rate in PVBG groups was 1.13 times of NVBG groups (P = 0.002); (ii) the PVBG groups reached bone union significantly earlier by 1.73 weeks (P < 0.01); (iii) there was no significant difference in functional results, including active range of motion, grip strength, Mayo Wrist Score and excellent and good rate (P > 0.05); and (iv) re-operation rate was similar between the two groups (P = 0.65).

CONCLUSIONS

Although the PVBG technique attains higher union rate and earlier union, this radiological advantage does not bring any functional benefits. In addition, PVBGs are of greater technical difficulty and need more operation requirements. Hence, clinicians should be cautious in electing PVBGs for treating scaphoid non-union.

3D Printing for scaphoid-reconstruction with medial femoral condyle flap

Three-dimensional (3D) printing has emerged as an innovative technology to derive a maximum benefit from high-resolution tomography images and virtual 3D reconstructions. The present study describes a novel technique using a 3D printed model for harvesting osteochondral medial femur condyle (MFC) flap to replace the proximal pole of the scaphoid in case of proximal avascular pole. MFC bone grafting has already proved to be reasonable surgical method for this indication. To refine this technique, we introduce a 3D model of the proximal scaphoid pole on a handlebar with anatomic orientation marks on its surface, which was virtually planned via 3D imaging and finally 3D printed. This 3D model was sterilized and facilitated several intraoperative steps, such as resecting the proximal pole, simulating the alignment of the future MFC flap, detecting the most feasible harvest site, reducing the donor site morbidity and precisely modeling the graft. In summary, 3D printing is an innovative, feasible technology to aid in various surgical steps while performing a MFC flap for posttraumatic avascular proximal scaphoid pole. It enhances the surgeon's perception of complex patient-specific pathologies and intraoperative accuracy. Especially, we emphasize the benefit of a handlebar on the 3D model, because it enormously improves its maneuverability and usability.

[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.

[Scaphoid pseudarthrosis : Complex reconstruction using vascularized bone grafts]

The most important goals of scaphoid reconstruction in pseudarthrosis are correction of the humpback deformity, the realignment of the proximal carpal row and the bony union of the scaphoid. Therefore, in most cases bone grafting is required. To increase the healing rate and to improve vascularization, several kinds of vascularized bone grafts have been developed. Pedicled grafts are preferably harvested from the dorsal or palmar side of the distal radius with fusion rates between 27% and 100%. Free microvascular grafts can be obtained from the iliac crest and the medial or lateral femoral condyle with fusion rates between 60% and 100%. For their application microsurgical equipment and skills are required. Up to now osteochondral grafts from the femoral condyle offer the only chance for joint surface replacement by transferring part of the surface of the femoropatellar joint. The use of vascularized grafts is still a matter of controversy, since their superiority is still unproven compared to nonvascularized grafts, which also achieved 100% fusion rates in several series. They are indicated in secondary procedures after failed reconstruction and nonunion with small avascular proximal pole fragments. Since no evidence-based guidelines exist, this article provides an experience-based treatment algorithm for scaphoid nonunion with special consideration to vascularized bone grafts.