Nonunions by Animesh Agarwal

Author:Animesh Agarwal
Language: eng
Format: epub
Publisher: Springer US, Boston, MA

After implant choice, the next steps in the treatment algorithm are surgical approach and choice of bone graft material. A combination of fracture stability and alignment, bone reabsorption, presence of osteonecrosis, and previous surgical intervention is used to determine the surgical approach and bone graft source.

7.5.2 Scaphoid Nonunion Without Osteonecrosis

Well-aligned, stable nonunions with evidence of substantial bone loss or osteonecrosis represent the one category of fracture in which need for intra-operative bone graft remains controversial. A study by Shah and Jones found that fractures with a stable fibrous nonunion or intact cartilage cap healed without need for bone graft [111]. Additional studies by Slade et al. and Ikeda et al. demonstrated similar results, reporting healing of all nonunions treated with screw fixation alone if sclerosis was less than 1–2 mm on CT scan. Of note, fractures treated within 6 months of initial injury healed faster than older injuries [112, 113]. Fracture location determines surgical approach, with most authors recommending a volar approach for waist fractures in order to preserve the remaining dorsal blood supply and a dorsal approach for proximal pole fractures, which allows improved access and reduces the risk of displacing the proximal pole with guidewire placement [36, 65, 83].

Fractures that are well perfused, but with substantial bone loss, require the use of bone autograft to provide structural stability and enhance healing potential. The choice of cancellous versus corticocancellous structural graft remains an area of controversy. Geissler, Slade, and Gillon have argued that arthroscopically guided percutaneous fixation, and bone grafting is adequate for healing in nondisplaced or minimally displaced fractures with fibrous stabilization of the fracture site [65, 114]. In their technique, cancellous bone autograft is harvested from either the distal radius or iliac crest using a bone biopsy needle. A guidewire is then place within the scaphoid using a percutaneous of mini-incision dorsal approach. A second wire is placed as an anti-rotation wire, and arthroscopy is performed to confirm the presence of the fibrous nonunion, assess vascularity, and rule out ligamentous injury. Under arthroscopic visualization, a dorsal capsular release is performed using a curved hemostat through the 3,4 portal. The arthroscope is then removed, and the scaphoid is drilled for the compression screw. The guidewire is left in place, and bone biopsy needle is placed over it to deliver bone graft. Finally, a compression screw 4 mm shorter than the measured length of the scaphoid is placed. Using this technique on 108 scaphoid fracture nonunions with either no displacement or a reducible humpback deformity, Slade and Gillon reported a 96% healing rate at 9 months. Ten cases of delayed healing required repeat percutaneous bone grafting [114]. Percutaneous bone grafting can also be performed through a limited volar approach, in the setting of a nondisplaced fracture nonunion. Using this technique, only the scaphotrapezial joint in exposed in the volar approach. The volar beak of the trapezium is removed to allow grafting and retrograde screw placement [36].

Other authors would argue that a corticocancellous graft is required for structural stability and that only an open approach allows complete evacuation of sclerotic bone, which can prevent healing.

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