Treatment of degenerative arthrosis

Degenerative changes, not related to fracture or dislocation, typically affect the second and third CMC joints, and result in dorsal hypertro-phic osteophyte formation. Patients present complaining of a tender prominence over the interval between the two joints. The pain may result strictly from direct pressure or may be related to use and overuse of the digits, sometimes associated with extensor tendon subluxation over the dorsal prominence (Fig. 7). The prominence is firm and nonmobile, consistent with a bony

Reduccion Con Agujas Ksler
Fig. 6. (A) AP and (B) lateral radiographs following arthrodesis. The fourth CMC joint is stabilized with a 2.0-mm miniplate. The third CMC joint is stabilized with K-wires. The anatomy of the dorsal capitate did not allow placement of a plate without restricting joint motion.
Carpal Boss Surgery
Fig. 7. The bony projection is visualized between the extensor tendons. This patient's symptoms resulted from repeated tendon subluxation and the resulting inflammation.

mass. It is best visualized clinically with wrist flexion (Fig. 8), and best seen radiographically using a ''carpal boss view,'' with the wrist in 30° of supination and 30° of ulnar deviation (Fig. 9) [18]. The bony mass may be accompanied by mild soft-tissue swelling or a mass characteristic of a ganglion cyst.

In the great majority of cases conservative management suffices. When extensor tendon subluxation is present or a ganglion cyst accompanies the bony prominence, surgery is a more likely possibility. When persistent symptoms exist, the mass is approached through a dorsal transverse incision. If a ganglion cyst is present, it is located

Metacarpal Boss
Fig. 8. This dorsal third carpometacarpal boss is best visualized with wrist flexion.
Carpal Boss Excision
Fig. 9. Even without the "carpal boss view'' this lateral radiograph nicely depicts the dorsal third carpometacarpal boss (arrow).

and excised along with its capsular ''stalk.'' The osteophyte is exposed subperiosteally through a longitudinal incision, sometimes requiring limited elevation of the insertion of a radial wrist extensor. An osteotome (Fig. 10) is used to excise the osteophyte from the carpometacarpal joint down to the level of normal joint cartilage (Fig. 11). Palpation ensures complete resection and elimination of tendon subluxation. The dorsal tendon insertion, ligament, and capsule are repaired as required.

Most reports indicate that simple surgical excision of the osteophyte and associated ganglion

Fig. 10. Following subperiosteal exposure of the dorsal base of the third metacarpal and CMC joint, an osteo-tome is used to remove the bony projection down to normal articular cartilage.
Carpal Boss Surgery
Fig. 11. The elevator is pointing to the third CMC joint following complete boss resection.

provides effective symptom relief in greater than 90% of patients [12,19-21]. Persistent symptoms are thought to be caused by incomplete mass excision [12], regrowth of the bony prominence, or secondary instability. Interestingly, Citteur and coworkers [22] documented instability of the third CMC joint following a standard boss excision performed in cadavers. Passive range of motion at that joint approximately doubled. At surgery, this increased passive motion of the joint is apparent in many patients. It seems plausible that persistent symptoms, not attributable to incomplete excision, may relate to subtle joint instability. Ultimately, CMC joint arthrodesis may be required in such cases.

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