**14. Arthroscopic management of scaphoid nonunion**

Acute scaphoid fractures are often missed and patients return with pain when delayed union or nonunion manifests (**Figure 39a**).

The natural history of untreated scaphoid nonunions is progression to carpal collapse resulting in wrist arthritis and chronic painful disability [98, 99]. Osteoarthritis at the scaphoid-radial styloid joint is significantly associated with dorsiflexed intercalated segment instability (DISI) deformity. An overall incidence of DISI deformity of the wrist is about 56%, and the frequency of DISI pattern increased with longer duration of non-union [100]. Arthroscopic management of scaphoid nonunions without severe deformities or arthritis is effective [101]. This simplifies postoperative recovery, reduces complications, and preserves the wrist's capsuleligament complex—and, thus, the scaphoid's precarious vascularization [102]. Arthroscopic management of scaphoid nonunion is based on the following ideas: that scaphoid vascularity can be preserved because of the minimally invasive nature of arthroscopic surgeries; and that direct visualization with magnification can facilitate accurate debridement of the nonunion site, identify fibrous union and punctate bleeding from fracture site and aid perfect reduction [103].

Principles of the arthroscopic treatment of the scaphoid nonunions are the same as with other surgical techniques: excision of pseudrthrosis, correction of humpback deformity, restoration of the length of the bone, bone grafting and a stable fixation.

Surgical technique includes inspection of the radiocarpal joint via standard portals, synovectomy and arthroscopically guided styloidectomy, if necessary.

**Figure 39.**

*(a) X-ray of scaphoid nonunion, (b) shaver in the nonunion site, (c) defect of the scaphoid after removal of debris, (d) fixation of the scaphoid with K-wires, (e) defect filled with bone graft, (f) final x-ray after the surgery.*

#### *Wrist Arthroscopy DOI: http://dx.doi.org/10.5772/intechopen.99191*

Arthroscopic treatment of the nonunion is performed via midcarpal portals. The scope is inserted in MCU portal and instruments in MCR, accessory portal (close to the nonunion) or STT portal. If a frank bony defect is encountered, it is curetted with a fine-angled curette or motorized shaver (**Figure 39b**), until all fibrotic tissue and sclerotic bone are removed.

If the tourniquet is used, at this point it has to be released, to assess the vascularity of the bones. Any humpback and DISI deformity should be identified and corrected. Once the deformity of the scaphoid is corrected, fragments have to be transfixed with K-wires from the tubercle of the scaphoid to the proximal pole for provisional scaphoid fixation (**Figure 39c** and **d**).

This process is controlled under arthroscopic and fluoroscopic guidance. The bone graft is taken from the ipsilateral distal radius or iliac crest depending on the amount needed for filling the defect. The bone graft is inserted into a trocar and then the end of the trocar is placed at the nonunion site. The graft is pushed into the trocar with a blunt guide wire until the nonunion site is filled (**Figure 39e** and **f**).

Some surgeons recommend to add fibrin glue to protect the graft but others claim that once the scaphoid is fixed and the traction released, the capitate's native anatomical position will provide sufficient graft stabilization [102, 104]. The fragments are stabilized with screw(s) and/or K-wires. Recorded union rate with this procedure is 86 – 100% [105–107]. Arthroscopically treated patients achieve faster healing despite shorter time to surgery in the percutaneous group. Local bone grafting is considered as the main reason for this outcome [108].
