Treatment of dynamic scaphoid instability.

BACKGROUND

Chronic wrist pain attributable to scaphoid instability without fixed deformity (dynamic instability) presents a treatment dilemma. The diagnosis usually is delayed, missing the opportunity for direct repair. The intercarpal fusion, tenodesis, and capsulodesis procedures create a fixed deformity. This report presents an outcome study of a new treatment for dynamic scaphoid instability that spanned more than 5 years.

METHODS

Arthroscopic evaluation was used to confirm the diagnosis for 105 wrists of 102 patients who had experienced wrist pain for an average of 24.4 months. The treatment for these patients involved transferring two thirds of the extensor carpi radialis longus through the distal pole of the reduced scaphoid volarly to the intact flexor carpi radialis. The postoperative follow-up period averaged 63 months.

RESULTS

The average grip strength increased by 65%. The average active wrist extension-flexion increased by 9%, with an average radial deviation loss of 6 degrees. The overall results, as measured by the modified Green and O'Brien clinical wrist scale, were as follows: excellent (49%), good (24%), and fair (26%). Good to excellent results were reported by 85% of the patients. Pain relief was reported by 94% of the patients, and 93% of the patients would recommend the procedure to others.

CONCLUSIONS

Scaphoid instability without fixed deformity is a complex problem. Conventional treatments have drawbacks. The new technique produced positive results that are quite promising for the management of dynamic scaphoid instability.