Related Experiment Video
Updated: Apr 16, 2026
Author Spotlight: Ultrasound-Guided Needle Release Combined with Corticosteroid Injection for the Treatment of Supinator Syndrome
Published on: May 26, 2023
Association Between Thumb Hypoplasia, Radial Longitudinal Deficiency, and Radial Polydactyly
Emma Payne1, Charles A Goldfarb1, M Claire Manske2
1Department of Orthopaedic Surgery, Washington University School of Medicine, Saint Louis, MO.
Purpose:
The expression of the sonic hedgehog protein has been associated with induction of both radial longitudinal deficiency (RLD) and radial polydactyly in animal studies. We sought to investigate the co-occurrence of thumb hypoplasia/RLD and radial polydactyly in a large registry patient cohort and to investigate the clinical presentations of such patients.
Methods:
The Congenital Upper Limb Differences (CoULD) registry was queried for all patients with contralateral diagnoses of thumb hypoplasia/RLD and radial polydactyly, as defined by the Oberg-Manske-Tonkin classification system, between June 2014 and January 2026. The demographic information, medical and musculoskeletal comorbidities, radiographs, and clinical images were collected.
Results:
Ten patients were identified with contralateral diagnoses of thumb hypoplasia/RLD and radial polydactyly. The median age and interquartile range at time of enrollment was 1.67 (0.2-3.0), and 4 of the 10 were women. There was a wide range of diagnoses of thumb hypoplasia including type II, IIIA, IIIB, IV, V, and VII (unclassifiable), and two patients additionally had RLD (type 1 and type 3). There was a similarly a wide range of radial polydactyly classification, including type II, IV, V, VI, VII, and VIII (unclassifiable). Four had a syndrome diagnosis, four had medical comorbidities, and three patients had a history of other orthopedic conditions.
Conclusions:
This study demonstrated that with co-occurrence, there was no clear association in severity between thumb hypoplasia/RLD and radial polydactyly. There was minimal forearm involvement which has implications in timing of hand development. Additionally, there was a high degree of variability including syndromic conditions, as well as medical or orthopedic comorbidities. We recommend that clinicians are aware of this possible association and perform a thorough examination, as the identification of a mildly hypoplastic thumb would guide additional medical testing not typically performed in thumb polydactyly.
Type Of Study/Level Of Evidence:
Differential Diagnosis/Symptom Prevalence Study IV.
Related Concept Videos
01:09Bones of the Upper Limb: Radius
The radius has a nail-shaped head, and a...
01:15Bones of the Upper Limb: Ulna
01:09Changes in the Appendicular Skeleton with Age
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
01:22Spinal Nerves: Plexus I
The Cervical Plexus
The cervical plexus, formed by the anterior rami of the first four...
01:16Muscles of the Forearm that Move the Hand and Fingers
Anterior Compartment
The anterior compartment muscles originate from the humerus. They primarily function as flexors and are also known as flexor muscles. They typically insert on the carpals, metacarpals, and phalanges. The superficial layer includes the flexor carpi...
01:11Assessment of radial pulse
The radial pulse, located at the wrist, is often the preferred site for assessing peripheral pulse because of its accessibility and dependability. The process of determining the radial pulse involves several steps: