Scaphoid nonunion: what is the role of the Zaidemberg 1,2 intercompartmental supraretinacular arterial flap?

Volar rerouting of the 1,2 intercompartmental supraretinacular artery vascularized bone graft for middle and distal scaphoid nonunions

BACKGROUND

The bone graft vascularized by the 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) placed on the scaphoid by a dorsal approach is a technique used to treat scaphoid nonunions with avascular necrosis of the proximal pole and without significant bone loss or carpus collapse. We present the results of patients treated with a volar rerouting of the 1,2 ICSRA graft under the tendons of the first extensor compartment to treat more distal scaphoid nonunions than the proximal pole. The aim of this study was to assess the clinical and radiological outcomes of patients operated with this technique with the hypothesis that it would allow to treat more distal nonunions than those of the proximal pole.

PATIENTS AND METHODS

This retrospective study involved patients treated by a volar rerouting of the 1,2 ICSRA graft for nonunions of the middle and distal thirds of the scaphoid. Assessments included clinical outcomes and radiological bone consolidation. QuickDASH and Mayo Wrist scores were computed. Range of motion and grip strength were evaluated for both the operated and the contralateral sides.

RESULTS

Nineteen patients were followed-up for 33 months (range: 6-75). Mean postoperative QuickDASH score was 10 (range: 0-45), and mean Mayo wrist score was 85 (range: 50-100). Flexion and extension, ulnar and radial deviations were statistically different between the affected and healthy sides (p<0,05). Consolidation was achieved in 17 patients (89%).

DISCUSSION

This technical modification allowed good functional outcomes and scaphoid consolidation. It expands the classic indications of the vascularized 1,2 ICSRA bone graft to more distal nonunions than the proximal pole.

LEVEL OF EVIDENCE

IV.

Compound or Specially Designed Flaps in the Lower Extremities

Novel and combined tissue transfers from the lower extremity provide new tools to combat soft tissue defects of the hand, foot, and ankle, or fracture nonunion. Flaps can be designed for special purposes, such as providing a gliding bed for a grafted or repaired tendon or for thumb or finger reconstruction. Propeller flaps can cover soft tissue defects of the leg and foot. In repairing severe bone and soft tissue defects of the lower extremity, combined approaches, including external fixators, one-stage vascularized bone grafting, and skin or muscle flap coverage of the traumatized leg and foot, have become popular.

Vascularized Small-Bone Transfers for Fracture Nonunion and Bony Defects

Vascularized small-bone grafting is an efficient and often necessary surgical approach for nonunion or necrosis of several bones in particular sites of the body, including scaphoid, lunate, distal ulna, and clavicle. The medial femoral condyle is an excellent graft source that can be used in treating scaphoid, ulna, clavicle, or lower-extremity bone defects, including nonunion. Vascularized bone grafting to the small bones, particularly involving reconstruction of damaged cartilage surfaces, should enhance subchondral vascular supply and help prevent cartilage regeneration. Vascularized osteoperiosteal and corticoperiosteal flaps are useful for treating nonunion of long bones.

[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.

Wrist arthroscopy for the treatment of scaphoid delayed or nonunions and judging the need for bone grafting

This study reports outcomes of arthroscopy in the treatment of delayed or nonunions of 25 scaphoids (25 patients). The surgery was performed between 8 and 43 weeks after injury. Intraoperatively, 11 fractures were deemed stable to probing and underwent percutaneous screw fixation only; 14 were unstable and received arthroscopic bone grafting with percutaneous screw fixation. All fractures united. At a mean follow-up of 21 months (range 12-48), the mean Mayo wrist score was 96, and patient-rated wrist evaluation was 4, and the flexion-extension arc was 90% of the contralateral wrist. We conclude that arthroscopy is valuable in the treatment of scaphoid delayed or nonunions and in judging the need for bone grafting. Our data indicate that regardless of cystic formation in the scaphoid, bone grafting is not always necessary. Percutaneous fixation alone is sufficient when scaphoid delayed or nonunions are between 8 weeks and 1 year following injury, without scaphoid nonunion advanced collapse or dorsal intercalated segment instability, and when forceful probing confirms stability of the scaphoid arthroscopically. Level of evidence: IV.