Indications and Contraindications

The underlying pathology of radiocarpal arthritis frequently is due to trauma or degenerative changes or both. The leading causes are malunited or nonunited fractures of the radius or scaphoid, radiocarpal or intercarpal dislocations or dissociations, or forms of primary osteoarthritis or inflammatory arthritis. Management has focused on reducing pain to increase function, while, when possible, preserving some degree of motion, with total wrist arthrodesis being the ultimate salvage procedure.^1,2 Surgical approaches that attempt to preserve some motion have included proximal row carpectomy, four-corner fusion with and without scaphoid excision, radiolunate arthrodesis, radioscapholunate arthrodesis, and lunocapitate arthrodesis.^2–7

Motion-sparing surgical procedures require healthy articular cartilage at the site of preserved motion. For proximal row carpectomy, a healthy capitate head and lunate fossa are required; for a four-corner fusion, the lunate and its fossa of the radius must have a healthy articular surface. Radiolunate and radioscapholunate arthrodesis require a healthy midcarpal joint and can provide stability, but result in a significantly limited arc of motion and a moderately high failure rate because the scaphoid acts as a strut between the proximal and distal carpal rows.^2,8

Biomechanical studies have shown the effect of preserving versus osteotomizing the scaphoid on midcarpal joint motion, with osteotomy significantly increasing the degree of allowable motion through the midcarpal joint.^5,8 When the lunate and the scaphoid fossae are arthritic, but the midcarpal articulation of the capitate in its lunate and scaphoid fossae remains healthy, it is logical to attempt to preserve and use the midcarpal joint to retain motion, while eliminating pain through an arthrodesis of the arthritic radiocarpal surfaces.^2,9

This chapter describes a step-by-step technique of using a tensioned, flexible plating system (Small Bone Innovations, Morrisville, PA) to perform a scaphoid hemiresection and recessed arthrodesis of the radiocarpal joint (the SHARC procedure). This procedure allows the capitate to move within its midcarpal joint as a “universal” joint.⁸ The ideal candidate is a patient with radiocarpal arthritis and a healthy midcarpal articulation. Contraindications to performing the procedure are active local infection, systemic disease, midcarpal arthrosis, and unwillingness of the patient to comply with postoperative instructions and rehabilitation protocols.

Preoperative Planning

Patients with radiocarpal arthritis should have a thorough history, physical examination, and radiographic assessment. Patients usually have an extended history of wrist-related complaints with or without previous wrist trauma. These complaints may include pain, loss of strength, and considerable restriction of motion. Radiographic analysis (including computed tomography scans if needed) should show a smooth, regular contour of the capitate with maintenance of healthy articular cartilage of the midcarpal joint. The hamate and proximal pole of the scaphoid should have structural viability (no evidence of a vascular necrosis or collapse).

Surgery

For this outpatient procedure, patients are positioned supine, and standard preparing and draping techniques are applied. After appropriate preoperative antibiotics have been administered, an upper arm tourniquet is generally inflated to 250 mm Hg. The surgeries are performed under either regional axillary block anesthesia or general anesthesia. The patient’s arm is placed on the hand table in a fully pronated position. The surgeon is seated on the axilla side of the table with an assistant facing across.

Technique

A dorsal midline incision is used in all cases. The extensor retinaculum is step-cut and reflected, and the extensor tendons from the first through the fifth compartment are mobilized and retracted (Fig. 55-1). As an adjunct for postoperative pain relief, a posterior interosseous sensory neurectomy is performed (Fig. 55-2).¹⁰ The radiocarpal joint capsule is incised longitudinally and elevated medially and laterally exposing the entire distal radius, scaphoid, lunate, and midcarpal joint. The radiocarpal articulation should be assessed at this point, confirming the preoperative diagnosis of arthritic degeneration of the radioscaphoid and radiolunate articular surfaces with preservation of a healthy articulation at the capitolunate joint (Fig. 55-3).

FIGURE 55-1 Extensor retinaculum is step-cut and reflected with extensor tendons from the first through the fifth compartment mobilized.

FIGURE 55-2 Resection of the posterior interosseous sensory nerve for postoperative pain relief.

FIGURE 55-3 A and B, Inspection of the radiocarpal articulation showing arthritic degeneration of the radioscaphoid and the radiolunate articular surfaces with preservation of a healthy articulation at the capitolunate joint.

Residual degenerative articular surface of the proximal lunate and scaphoid is removed with a curet, rongeur, or high-speed bur (Fig. 55-4), and a bur is used to create a complementary recessed “cup” in the distal radial metaphysis (Fig. 55-5). The scaphoid is next osteotomized at its waist, and the distal half of the scaphoid is morcellated and sharply excised (Fig. 55-6