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Radial Styloidectomy
David M. Kalainov, Mark S. Cohen, and Stephanie Sweet
Excision of the radial styloid gained recognition in 1948 when Barnard and Stubbins1reported on ten scaphoid fracture nonunions treated with bone grafting and radial styloidectomy. The procedure has since been advocated to address radioscaphoid arthritis developing from a variety of injuries, includ- ing previous fractures of the radial styloid and scaphoid, and arthritis related to posttraumatic scapholunate instability.2–8
Resection of the radial styloid has also been a use- ful adjunct to other procedures where there is poten- tial for impingement between the styloid process and distal scaphoid or trapezium.9–15 Authors have in- cluded discussion of successful radial styloidectomy in descriptions of proximal row carpectomy, mid- carpal arthrodesis, and triscaphe fusion procedures.
On occasion, an individual may be too physically un- fit or unwilling to undergo an extensive operation to address a symptomatic scaphoid nonunion or scapho- lunate dissociation. A limited radial styloidectomy may be a reasonable alternative in these cases.
ANATOMY
The radial styloid is positioned slightly volar to the midcoronal plane of the radius. The bony excrescence is the origin for the palmar extrinsic ligaments inte- gral to carpal stability.16–18 The radioscaphocapitate ligament averages 7 mm in width and originates only 4 mm from the tip of the styloid process. The long ra- diolunate ligament is approximately 10 mm wide and starts 10 mm proximal to the tip of the styloid (Fig- ure 17.1).
Three basic types of styloid osteotomies have been described: short oblique, vertical oblique, and trans- verse (Figure 17.2). The potential for symptomatic carpal instability has been associated with the size and shape of the excised bone fragment. Siegel and Gel- berman18performed a cadaveric study to assess the ef- fect of these three styloidectomy configurations on ex- trinsic carpal ligament integrity. The short oblique osteotomy was the least damaging, with removal of only 9% of the radioscaphocapitate origin; this sty- loidectomy was found to leave the long radiolunate ligament attachment site intact. The vertical oblique
osteotomy removed 92% of the radioscaphocapitate and 21% of the long radiolunate ligament origins. The transverse osteotomy was the most invasive, detach- ing 95% of the radioscaphocapitate and 46% of the long radiolunate ligament origins.
In another cadaveric model, Nakamura et al19ex- amined the effects of increasingly larger oblique sty- loidectomies on carpal stability. They concluded that the procedure should be limited to a 3- to 4-mm bony resection. With axial loading, significantly increased radial, ulnar, and palmar displacements of the carpus were detected after removing 6-mm and 10-mm sty- loid segments. The 6-mm cut violated the radio- scaphocapitate ligament origin, whereas the 10-mm cut removed the radioscaphocapitate and a portion of the long radiolunate ligament origins. Only an in- significant change in carpal translation was detected after a 3-mm osteotomy.
Other ligament attachments to the radial styloid include the radial collateral ligament, the dorsal ra- diocarpal ligament, and the radioscapholunate liga- ment.16The radial collateral ligament originates radi- ally from to the tip of the styloid process and inserts into the waist and distal pole of the scaphoid. This structure represents the lateralmost margin of the ra- dioscaphocapitate ligament and is removed in all sty- loidectomy procedures. No adverse effects have been reported in the literature. The dorsal radiocarpal liga- ment has a broad origin from the distal radius, begin- ning radial to the level of Lister’s tubercle and cours- ing distally to its insertion into the triquetrum.
Violation of a portion of the dorsal radiocarpal liga- ment following styloidectomy may potentially affect carpal stability, but this has not been described. The radioscapholunate ligament is a vascular structure with limited mechanical function. The ligament orig- inates from the palmar aspect of the distal radius, in between the long and short radiolunate ligaments, and merges with the scapholunate interosseous ligament distally.
OPEN TECHNIQUE
The radial styloid may be excised as an adjunct to an- other carpal procedure; the styloid is approached
through the same incision or a separate incision in these cases. With an isolated styloidectomy, a straight incision is made between the first and second exten- sor tendon compartments (Figure 17.3). The incision is centered over the tip of the styloid process, with care taken to protect the dorsal branch of the radial artery and small branches of the radial sensory and lateral antebrachial cutaneous nerves.13
The extensor retinaculum and periosteum are in- cised longitudinally over the palpable styloid. The tip is exposed by subperiosteal dissection, preserving the palmar attachments of the radioscaphocapitate and long radiolunate ligaments. A small, straight os-
teotome is used to remove 3 mm to 4 mm of the tip at an oblique angle (Figure 17.4). The cut should be parallel to the projected course of the radioscapho- capitate ligament and perpendicular to the distal ra- dius articular surface (Figure 17.5).
Periosteum is reapproximated over the debrided styloid using absorbable sutures. The skin edges are repaired with subcuticular sutures in an effort to min- imize scar formation. A bulky gauze dressing is ap- plied, and the wrist is supported in neutral alignment with a volar plaster splint.
ARTHROSCOPIC TECHNIQUE
Finger traps are placed over the index and long find- ers, and the hand is suspended in an overhead traction
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FIGURE 17.1. The radioscaphocapitate and long radiolunate liga- ment origins.
FIGURE 17.2. Three radial styloidectomy configurations: short oblique, vertical oblique, and transverse.
FIGURE 17.3. Exposure for an open radial styloidectomy.
FIGURE 17.4. Excision of 3-mm bone fragment from the tip of the radial styloid.
device. The arm is secured to the extremity table with a well-padded strap for countertraction. The major ex- ternal landmarks and the positions of the portals that may be used in examining the wrist and performing the styloidectomy are shown in Figure 17.6.14,15
Eight to 10 pounds of traction are applied to the fingers to distract the wrist joint. The 3-4 portal is es- tablished to accommodate the arthroscopic camera.
Outflow is achieved by placing an 18-gauge needle or small plastic cannula through the 6-U portal. A com- plete examination of the wrist is performed.
The 1-2 portal is then established for access to the radial styloid (Figure 17.7). A limited resection of 3 mm to 4 mm of the styloid tip is performed using a covered bur (2.9 mm to 3.5 mm) and/or full-radius shaver (2 mm to 2.9 mm). A small osteotome or pituitary rongeur may be helpful in removing hard
subchondral bone. Use of a laser device may also be considered.20 The radioscaphocapitate and long ra- diolunate ligaments are visualized directly with the camera and adequate bone resection is confirmed with a mini-fluoroscopy unit (Figure 17.8). The procedure may be converted to an open technique if visualiza- tion is compromised.
The portal sites are either left open or closed with sutures. A bulky gauze dressing and volar plaster splint are applied with the wrist in neutral alignment.
REHABILITATION
Following an isolated radial styloidectomy, the dress- ing, splint, and sutures are removed after 1 week. A
FIGURE 17.5. Fluoroscopic image of the wrist following an oblique radial styloidectomy.
FIGURE 17.6. Anatomic landmarks and portal sites for an arthro- scopic wrist examination and radial styloidectomy.
FIGURE 17.7. Resection tool in the 1-2 portal and arthroscopic camera in the 3-4 portal.
FIGURE 17.8. Fluoroscopic image of the wrist during an arthro- scopic radial styloidectomy.
gradual return to work and sport activities is permit- ted. Assistance from a hand therapist may be helpful for instruction on wrist motion and grip strengthen- ing exercises. The period of wrist immobilization will be necessarily extended if a concurrent procedure pre- cludes early joint motion.
COMPLICATIONS
Complications inherent to any orthopedic procedure apply to both open and arthroscopic radial styloidec- tomies (e.g., infection, joint stiffness, keloid forma- tion). Specific problems that may result from a radial styloidectomy include injury to the dorsal branch of the radial artery and neuropraxia or neurotmesis of lo- cal sensory nerves (i.e., dorsal branches of the radial sensory and lateral antebrachial cutaneous nerves). A complex regional pain syndrome may develop follow- ing any nerve injury, necessitating intensive therapy and pain management intervention. An incomplete ra- dial styloidectomy may also be problematic, with per- sistent complaints of radial-sided wrist pain. Exces- sive bony resection is potentially disastrous, resulting in ulnar translation of the carpus and symptoms of wrist joint instability.
A radial styloidectomy is contraindicated when there is preexisting ulnar translation of the carpus or incompetence of the radioscaphocapitate and long ra- diolunate ligaments. This procedure alone will not ad- equately address arthritic changes that extend beyond the distal radioscaphoid articulation (i.e., degenerative arthritis involving the lunatocapitate joint secondary to chronic scapholunate instability or an untreated scaphoid nonunion). A concurrent operation to ad- dress the midcarpal arthritic changes should be con- sidered in these cases.
RESULTS
We reviewed 7 patients who underwent an arthroscopic or arthroscopically assisted radial styloidectomy be- tween 1992 and 1997. Three patients had scaphoid nonunions with posttraumatic arthritis involving the radioscaphoid articulation, 2 patients had radioscaphoid arthritis developing after a healed scaphoid fracture, one patient had arthritic changes involving the ra- dioscaphoid articulation secondary to a scapholunate ligament injury, and one patient had isolated arthritis of the radioscaphoid joint of unknown cause. All these patients elected surgery after failing to experience pain relief with conservative treatment measures.
In addition to a radial styloidectomy, one individ- ual underwent arthroscopic removal of nearly the en- tire scaphoid bone, and another individual underwent arthroscopic excision of the scaphoid proximal pole;
both patients presented with scaphoid nonunions.
Temporary wrist immobilization was implemented postoperatively in all cases.
The mean follow-up period for these 7 patients was 29 months (range 3 to 57 months). The Mayo modi- fied wrist scores21 increased from an average of 62 points preoperatively to 75 points postoperatively.
Two patients reported no residual pain, and 5 patients described only mild, occasional pain. Six patients re- turned to regular employment activities, whereas one patient was able to work but was unemployed. None of the patients described difficulty performing activi- ties of daily living.
CONCLUSION
Arthroscopic radial styloidectomy is a useful treatment for symptomatic arthritis localized to the distal ra- dioscaphoid articulation, either as an isolated technique or as an adjunct to another carpal procedure. The pro- cedure is minimally invasive with the potential for tem- porary pain relief and improved hand function. The de- tails of the technique are important to review in order to avoid injury to cutaneous nerves, the dorsal branch of the radial artery, and the palmar radiocarpal liga- ments. The bony resection should be limited to 3 mm to 4 mm, preserving the origins of the radioscaphocap- itate and long radiolunate ligaments.
References
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