Outcome measures used to assess the web-spaces of the hand – a systematic literature review

Aims: To compare methods assessing the anatomy of normal hand web-spaces. This is to inform subsequent use in accurate planning and evaluation of post-operative outcomes for web-space reconstructions, such as syndactyly repair.

Methods: A systematic review of the MEDLINE and EMBASE databases from conception to December 2024 was completed. Methods evaluated included those assessing the web-space arches, depth, width, height, form, abduction angle, slope angle, colour, and their reliabilities. Inclusion criteria comprised of healthy participants of any ethnicity or age, and peer-reviewed papers in any language. Exclusion criteria included papers exclusively assessing abnormal web-spaces, abstract-only publications, participant samples sizes of less than ten to ensure reproducibility across heterogenous hands, uninterpretable papers due to poor copy quality, and studies inadequately assessing the web-space (this included nil assessment, unclear aims of measurements, and use of non-geometric or radiographic methods).

Results: 11 papers were included. For the first web-space, seven papers were identified. All assessed the abduction angle, four assessed width, and one assessed the dorso-palmar web length and web-space area. For the second to fourth web-spaces, four papers were identified. All assessed the abduction angle and height as a ratio (one also included the height measured singularly), one assessed width, and one assessed slope angle. Interestingly, where assessed, no difference was identified across all parameters between these web-spaces.

Conclusions: Several methods of defining the webspace have been used. However, the specificity of the landmarks used is variable. Reproducibility analysis is inconsistently available, thus precluding reliability assessment. Promising methods have been identified however some may need validation. Other considerations include researcher priorities in assessment. Although no significant differences were identified between the second to fourth web-spaces, we speculate that stratification against height may be beneficial. Lastly, web-space colour is a key post-operative issue, yet there is limited assessment, demonstrating scope for further studies.