59 Scaphoidectomy and Four-Corner Fusion
When a patient desires motion-preserving salvage surgery for treating certain forms of posttraumatic wrist arthritis, scaphoid excision combined with intercarpal arthrodesis is a popular procedure that provides good subjective and objective outcomes. This chapter reviews the indications and contraindications for this procedure. The reader is provided a detailed description of surgical steps, including the three most popular fixation techniques.
When a patient desires motion-preserving salvage surgery for treating certain forms of posttraumatic wrist arthritis, scaphoid excision combined with four-corner fusion is a popular procedure that provides good subjective and objective outcomes.
59.2 Key Principles
Four-corner fusion with scaphoidectomy is preferred over proximal row carpectomy (PRC) when capitolunate arthritis is present or when the patient is younger than 40 years of age. Fixation options for four-corner fusion include K-wires, staples, headless compression screws, or intercarpal fusion plates. 1
Patients should expect to maintain approximately 50 to 60% normal wrist range of motion. Grip strength usually improves to 80% of the uninjured side. Complete recovery may be prolonged, taking 6 to 12 months. 2 , 3 , 4 , 5
Stage 2 or 3 scapholunate advanced collapse (SLAC) wrist and scaphoid nonunion advanced collapse (SNAC) wrist. Less common indications include radiocarpal arthrosis, certain carpal instability patterns, and failed soft tissue reconstructions, as long as there is preservation of the radiolunate articulation.
Radiolunate arthritis, Kienbock’s disease, patient’s desire for one-stage definitive treatment, and advanced pan arthritic changes accompanied by severely restricted range of motion and pain.
59.6 Special Considerations
Plain radiographs: PA, lateral, ulnar deviation, and clenched fist views are usually sufficient for diagnosis and may reveal excessive flexion of scaphoid, scapholunate widening, and radiocarpal and/or midcarpal arthritis (► Fig. 59.1). We often obtain views of the contralateral wrist for comparison. When the condition of the radiolunate joint is unclear, magnetic resonance imaging (MRI), computed tomography (CT), or diagnostic wrist arthroscopy can be helpful.
59.7 Positioning and Anesthesia
Regional anesthesia with sedation is preferred. The patient is placed supine, with extremity on a hand table and proximally applied tourniquet. It is easier to perform the procedure when the surgeon sits on the side of the extremity that allows them to operate in a proximal to distal direction on the dorsal wrist and forearm.
59.8 Tips, Pearls, and Lessons Learned
The superficial approach is usually through the third extensor compartment; preserving retinaculum over the fourth compartment minimizes postoperative finger stiffness. Transection of the posterior interosseous nerve (PIN) at this stage may decrease postoperative pain.
The dorsal wrist capsule consists of the dorsal radiocarpal ligament (DRC) and the dorsal inter-carpal ligament (DIC) with conjoint insertion on triquetrum. Arthrotomy is achieved with a proximally based “T” or a ligament-sparing approach. 6 Longitudinal traction by an assistant opens up the carpus and allows maximum exposure of the lunate and triquetrum.
One may attempt to excise the scaphoid in one piece. This is facilitated by using a threaded K-wire or carpal corkscrew as a joystick in the scaphoid. When excising this bone, ensure that the volar radiocarpal ligaments are protected. This may necessitate piecemeal excision of the scaphoid.