Analysis of functional outcome after posttraumatic thumb reconstruction in comparison to nonreconstructed amputated thumbs at the proximal phalanx of the thumb ray: a mid-term follow-up with special attention to the Manchester-modified M2 DASH questionnaire and effect size of Cohen's d.

Background: Pollicization, toe to thumb transfer, and osteoplastic thumb reconstruction, along with free tissue transfer, are the most reported reconstructive procedures after traumatic amputation at the proximal and middle third of the thumb. We will present our clinical studies on functional outcomes with special attention to the M2 DASH questionnaire and effect size of Cohen's d.

Methods: Eleven patients (2 women and 9 men) with posttraumatic thumb reconstruction (three pollicizations of the index or index stump, four free lateral arm osteocutaneous neurosensory flaps, and four microvascular second toe to thumb transfers), performed during the period 2000 to 2007, were reexamined after 4.2 (SD ±2.1) years (range, 2-7 years postinjury). To ensure homogeneity among the patients' data, we selected only patients with isolated thumb amputations at the level of the proximal phalanx.

Results: The total M2-DASH score after thumb reconstruction was 18.55 (SD ±16.79). The M2-DASH score of patients with nonreconstructed thumbs was 32.77 (SD ±18.87). Pairwise comparisons between reconstructed and amputated thumbs showed statistically significant differences (Wilcoxon rank-sum test, p value = 0.03) and a highly effective improvement of hand function (Cohen's d = 1.10) after thumb reconstruction relative to amputated thumbs.

Conclusion: Before selecting a candidate for thumb reconstruction, it is critical to decide on an individualized treatment plan. Factors such as the patient's occupation and the importance of the aesthetic appearance of the thumb must be carefully considered. The surgeon must investigate the patient's current use pattern and functional requirements before considering a reconstructive treatment.