Morphometrics of the human thumb metacarpal bone: interest for developing an osseointegrated prosthesis

Osseointegrated Metallic Implants for Finger Amputees: A Review of the Literature

Digital trauma amputations and digital agenesis strongly affect the functionality and aesthetic appearance of the hand. Autologous reconstruction is the gold standard of treatment. Unfortunately, microsurgical options and transplantation procedures are not possible for patients who present contraindications or refuse to undergo transplantation from the toe (e.g. toe‐to‐thumb transplantation). To address these issues, osseointegrated finger prostheses are a promising alternative. The functional assessments registered during follow‐up confirmed the promising outcomes of osseointegrated prostheses in the treatment of hand finger amputees. This review outlines (a) a detailed analysis of osseointegrated finger metallic components of the implants, (b) the surgical procedures suggested in the literature, and (c) the functional assessments and promising outcomes that demonstrate the potential of these medical osseointegrated devices in the treatment of finger amputees.

Bony anatomy of the third metacarpal and relationship with the capitate: a computed tomography study

PURPOSE

The purpose of this study was to accurately establish the anatomical variability of the third metacarpal, its medullary canal, and the relationship with the capitate in the context of high rates of component loosening still seen in total wrist arthroplasty.

METHODS

CT scans of a 100 hands (age: 41 ± 14 years (range: 16-71 years); male/female ratio: 53/47) were studied to establish the detailed anatomy of the third metacarpal and the capitate.

RESULTS

Although the shape of the third metacarpal and the angles formed with the capitate were highly variable, the third metacarpal length was longer in males (p < 0.001), the proximal cortical bone was thicker (p < 0.001) and the sagittal metacarpal-capitate axis offset was greater (p = 0.01). A relationship was found between the total length of the metacarpal and the distance to the isthmus from the base (r = 0.63; p < 0.0001) which was unaffected by gender. No age-related relationships were significant.

CONCLUSION

The anatomy of the third metacarpal and capitate varies considerably more than has been alluded to in current wrist arthroplasty literature. Differences between males and females can likely be attributed to hand size. The distance of the isthmus from the base can be predicted from the total length of the metacarpal with a standard error of 1.9 mm.