Thumb in the plane of the hand: characterization and results of surgical treatment.

PURPOSE: The purpose of this retrospective investigation is to characterize a congenital deformity, the thumb in the plane of the hand (TPH), and to evaluate the results of abduction-rotation osteotomy of the thumb metacarpal with thumb web space deepening (WSD).

METHODS

We performed a comprehensive analysis of the medical records, hand therapy notes, and radiographs to evaluate clinical features of the TPH deformity. We evaluated clinical and radiographic outcomes and incidence of deformity recurrence after abduction-rotation osteotomy and thumb WSD.

RESULTS

Thirteen patients (7 girls and 6 boys) with 14 affected hands treated with an abduction-rotation osteotomy of the thumb metacarpal and formation of a deepened thumb-index web space met inclusion criteria. All TPH deformities were associated with other congenital conditions, including symbrachydactyly, syndactyly, central deficiency, and ulnar deficiency. During the course of treatment, patients had a mean of 4 surgeries per hand; 3 hands required osteotomy revision with or without revision WSD, and 6 additional hands required revision of thumb WSD alone. None of the affected hands were capable of thumb opposition to any finger before surgery, whereas after surgery, all 14 hands could actively perform key pinch, and 9 of the 14 hands could actively oppose the thumb to at least 1 finger.

CONCLUSIONS

The TPH deformity occurs in association with other congenital abnormalities of the hand. An abduction-rotation osteotomy of the thumb metacarpal with thumb WSD can restore thumb opposition and improve function; nonetheless, multiple surgical procedures are often required, and thumb function may remain limited.

TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.