Completed Research Studies

Purpose: This study aimed to develop a new way to classify a condition called ulnar polydactyly type A, where a child is born with a well-formed, extra small finger. The goal was to create a system that helps doctors better understand the condition and make decisions about surgery, especially for the more complex cases.

Findings: The study looked at 125 hands with the well-developed extra finger type, from 84 children. We found six different types based on how the bones in the hand are formed. Each type has its own plan for how surgery should be done. The new system was very reliable, meaning different doctors agreed on how to classify the cases, and it was very useful for planning treatment. The new system has been accepted by doctors and could help improve care and outcomes for children with this condition.

Read full article: The CoULD Ulnar Polydactyly Classification: A Multicenter Analysis – PubMed

Purpose: This study aimed to explore the connection between race, genetic syndromes, and type A and type B ulnar polydactyly. Researchers also looked at the relationship between race and family history in these children.

Findings: Ulnar polydactyly is usually not linked to a genetic syndrome. However, children with fully formed extra small fingers (type A) are more likely to have other health issues caused by a genetic syndrome compared to those with smaller, less developed nubbins (type B). This means that children with fully formed extra small fingers (type A) may benefit from extra genetic testing to check for other medical conditions and to help families understand their child’s health needs.

Read full article: Predictors of Syndromic Association in Ulnar Polydactyly: Analysis of a Multicenter Congenital Hand Differences Registry in the United States – PubMed

Purpose: This study focused on symbrachydactyly, a condition where children are born with small or missing fingers. Doctors often use systems to describe these differences, but those systems don’t always give enough detail to help plan treatment or explain what to expect. The researchers looked at two specific types—short finger and cleft types—using photos and X-rays from the CoULD Registry to find clearer ways to describe them.

Findings: Pediatric hand surgeons were able to identify consistent patterns in each type, helping tell them apart more reliably. However, they found that these patterns didn’t show a clear range of severity—one type wasn’t worse or better than the other. This study is a step toward creating a better system to guide care and support families in understanding the condition.

Read full article: Revisiting short finger and cleft type symbrachydactyly subtype differentiation utilizing the congenital upper limb differences (CoULD) registry – PubMed

Purpose: Children with an underdeveloped thumb may benefit from surgery to improve function. Sometimes, it’s hard to tell what type of surgery is necessary in a baby. This study looked at whether X-rays (radiographs) can help tell the difference between two types of thumb underdevelopment, Blauth IIIA and IIIB. 

Findings: There are certain characteristics seen on X-rays that help hand surgeons decide what type of surgery is best for the child. These characteristics include the shape of the bones or the length and width compared to other bones in the hand.

Read the full article: “Radiographic features of the metacarpal in Blauth type III thumb hypoplasia“

Purpose: This study looked at how doctors tell the difference between two conditions, symbrachydactyly and transverse deficiency, by examining the presence of nails, skin, or nubbins and the length of the missing part of the hand.

Findings: The presence of nubbins makes it more likely for doctors to diagnose symbrachydactyly. A deficiency closer to the fingertips (distal) is much more likely to be diagnosed as symbrachydactyly compared to a deficiency closer to the wrist (proximal). Describing both the location of the hand difference and the presence of nubbins helps doctors make a clearer diagnosis.

Read the full article: “Do nails and nubbins matter? A comparison of symbrachydactyly and transverse deficiency phenotypes“

Purpose: This study focused on the caregivers of children in the CoULD Registry to better understand their needs and find ways to improve the care we provide for the whole family.

Findings: Caregivers of children with congenital upper limb differences reported that their child’s condition had a significant impact on family life. Families with fewer resources, such as single-caregiver or economically disadvantaged households and those with children whose condition affects both arms, experienced greater impact. These results highlight the need to identify families at higher risk and support them in a more comprehensive way.

Read the full article: “The impact on families of children with congenital upper extremity differences“

Purpose: Accurate diagnosis of congenital upper extremity differences is important for many reasons. An international effort was made to investigate difficult-to-classify cases. The CoULD Study Group participated through presentation of cases and discussion. 

Findings: The OMT (Oberg, Manske, and Tonkin) classification achieved 93% agreement on difficult-to-classify cases. From this effort, a few unique groups were identified that did not classify easily and support the role of future genetic testing to fully diagnose these patients.

Read the full article: “The Oberg, Manske, and Tonkin classification of congenital upper limb differences“

Purpose: This study aimed to better understand the different types of ulnar longitudinal deficiency (ULD) and determine whether the severity of hand involvement is linked to more severe issues in the entire upper limb.

Findings: We found that children with more severe hand involvement often have more severe forearm involvement. Many of these children also have other medical or musculoskeletal conditions. Based on these results, we recommend that all patients with ULD undergo a heart evaluation and a detailed spine exam, as heart (8.0%) and spine (6.7%) issues are common in this group.

Read the full article: “An analysis of associated conditions and the relationship between the severity of hand manifestations with that of the forearm in ulnar longitudinal deficiency” 

Purpose: This study explored the patterns of genetic syndromes in children with congenital upper limb differences with the idea that these syndromes might follow predictable patterns.

Findings: 13 out of 100 children in the CoULD registry have a syndrome. 58 syndromes were seen in just one patient, 48 in two or more patients, and 23 in five or more patients. The most common syndromes were VACTERL association and Poland Syndrome.

Rare syndromes that appear in only one patient are less likely to be familiar to pediatric hand surgeons, so consulting a geneticist can help ensure proper diagnosis and care.

Read the full article: “Syndromic involvement of patients presenting with congenital upper limb anomalies: An analysis of 4,317 cases“

Purpose: Patients with Madelung’s deformity tend to seek care in early adolescence. These patients may experience wrist pain and decreased range of motion. This study examined patient and caregiver perceptions of the impact of Madelung’s deformity on functional limitations and psychosocial well-being.

Findings: Most patients with Madelung’s deformity were around 13 years old, mostly girls (98%), and primarily White (82%). Seventy-four percent had deformity limited to the lower part of the radius. Interestingly, patients with Madelung’s deformity overall reported decreased arm function, but do not report increased pain or worse psychosocial well-being.

Read the full article: “Patient and caregiver impressions of the impact of Madelung’s deformity: A CoULD Registry analysis“

Purpose: This study aimed to find the most reliable way to classify forearm involvement in patients with hereditary multiple osteochondromas (HMO), a condition where people have multiple abnormal benign bone growths, usually near the joints.

Findings: We found that the Masada classification was less reliable than the Gottschalk and Jo classifications for describing osteochondromas in the forearm. Each classification has its strengths and weaknesses, but we think there is a need for a more comprehensive system.

Read the full article: “Reliability of the Masada classification for forearm involvement in patients with hereditary multiple osteochondromas (HMO)“

Purpose: This study looked at how social factors, such as geographic location, race, parent education, and medical conditions, affect how parents and children report outcomes for children with congenital upper limb differences.

Findings: We found that social factors can influence reported outcomes. Overall, there were no major differences in scores based on geographic region, except that parents in the Midwest reported better upper extremity function compared to parents in the West. Black children reported higher levels of depression, pain, and anxiety, and lower upper extremity function compared to white and Asian peers. Children with additional medical conditions also reported worse outcomes. However, there were no differences based on sex, ethnicity, or parent education.

Read the full article: “Effect of race and geography on patient- and parent-reported quality of life for children with congenital upper limb differences” 

Purpose: Our researchers aimed to determine if pregnancy factors (for example, high blood pressure or diabetes) are associated with congenital arm differences. 

Findings: We found that of the patients enrolled in CoULD, two thirds of families did not report a risk factor during pregnancy. Of the remaining one third that reported having risk factors, we found that gestational diabetes was associated with having an increased risk of medical and orthopedic conditions, along with a congenital difference involving the entire arm.

Read the full article: “How risky are risk factors? An analysis of perinatal risk factors in patients participating in the CoULD registry“

Purpose: In this study, researchers reviewed the data of the children in the CoULD Registry with bony tumor conditions to gain a better understanding of the impact of these conditions on patients and their families.

Findings: This study concluded that patients with upper extremity bony tumors have worse overall function compared to population norms. In addition, patients with multiple bony tumors reported more pain and poorer physical function than those with an isolated bony tumor. Physicians should be alert to the physical and psychosocial burden of this disease.

Read the full article: “The impact of isolated versus multiple osteochondromas: Analysis of the CoULD Registry“

Purpose: This study wanted to see how congenital conditions in the CoULD registry compare with previous research studies. It aimed to see which conditions are most frequent when a registry starts enrollment.

Findings: Compared to other studies looking at common congenital differences, the CoULD registry at the beginning included more conditions that present to a hand surgeon later in childhood or might not need surgery. The most common conditions in the CoULD registry were having extra thumbs (radial polydactyly), benign bone growths (osteochondromas), shorter fingers (symbrachydactyly), and joined bones in the forearm (radioulnar synostosis).

Read the full article: “Congenital Upper Limb Differences Registry (CoULD): Registry-inclusion effect“

Purpose: This study aimed to explore whether there was a difference between how birth parents and parents of adopted children view their children’s mental health and abilities.

Findings: Overall, there were no major differences in the way parents of adopted and non-adopted children rated their child’s health and functioning, except for their child’s ability to use their arms and hands. This suggests that, in general, adopted children with congenital conditions affecting their arms and hands are viewed similarly by their parents as children born into their families.

Read the full article: “The effect of adoption on functioning and psychosocial well-being in patients with congenital upper-extremity differences“

Purpose: This study looked at children with severe thumb underdevelopment (hypoplasia) and other unusual hand differences that didn’t fit well into existing classifications.

Findings: The most common forearm difference in children with severe underdeveloped thumbs was the absence of the radius bone, known as type IV radial deficiency. About half of these children also had a related syndrome. To improve how doctors describe this severe form of hand difference, we modified the current classification system for thumb hypoplasia by refining type IV.

Read the full article: “Defining features of hand anomalies in severe thumb hypoplasia: A classification modification“

Purpose: This study looked at three common ways to classify thumb polydactyly (extra thumbs) in 150 patients from the CoULD Registry. The researchers also wanted to learn how often different types of thumb polydactyly occur in a North American population.

Findings: The researchers found that the Wassel-Flatt and Rotterdam classifications were more reliable than the Chung classification. They also suggested modifying the Wassel-Flatt system to include a subtype for smaller, underdeveloped thumbs (hypoplastic) to classify over 90% of cases that were previously unclassifiable.

Read the full article: “A comparative analysis of 150 thumb polydactyly cases from the CoULD Registry using the assel-Flatt, Rotterdam, and Chung classifications“

Purpose: The objective of this study was to determine if financial and social challenges, such as limited resources, affect how children with congenital hand differences perceive their own abilities and emotional well-being.

Findings: Children with congenital hand differences scored similarly to their peers without hand differences. However, children in more socially deprived areas experienced more pain, had worse relationships with peers, and reported higher levels of anxiety and depression, indicating greater psychosocial challenges.

Read the full article: “Social deprivation and congenital upper extremity differences: An assessment using PROMIS“

Purpose: The study aimed to understand how children with arthrogryposis, a condition affecting joint movement, feel about their physical abilities and emotional well-being using questionnaires called PODCI and PROMIS.

Findings: Children with arthrogryposis have more difficulties with using their arms compared to other kids, but their emotional health is similar to that of their peers. Those with a type called amyoplasia, which affects the entire arm, have more challenges with activities than those with a type called distal arthrogryposis, which affects only the hand.

Read the full article: “Patient-reported outcomes in arthrogryposis“

Purpose: Children born with a short or missing radius bone in their arm (called radial deficiency) often have thumbs that are smaller or underdeveloped. This study looked at whether more severe cases of radial deficiency are linked to more severe thumb underdevelopment and whether this is more common in children with certain syndromes.

Findings: We found that the more severe the radial deficiency, the more underdeveloped the thumb tends to be. Children with both radial deficiency and related syndromes, such as Holt-Oram or Fanconi anemia, are about two-and-a-half times more likely to have underdeveloped thumbs.

Read the full article: “Association of radial longitudinal deficiency and thumb hypoplasia: An update using the CoULD Registry“

Purpose: This study aimed to find out how children with congenital hand differences feel about their abilities and emotions before they have surgery. The CoULD registry uses two questionnaires called PODCI and PROMIS to ask about children’s feelings and abilities.

Findings: For children with congenital hand differences, the PROMIS questionnaire is comparable to the PODCI questionnaire in describing upper limb ability, pain, and depression. Because it is shorter, the PROMIS questionnaire may provide similar information while reducing patient/family time and effort.

Read the full article: “Convergent validity of PODCI and PROMIS domains in congenital upper limb anomalies“

Purpose: This study aimed to characterize the functional, emotional, and social impact of congenital upper limb differences on affected children and families before treatment.

Findings: In this study of almost 600 CoULD patients, children with congenital hand differences had decreased upper limb function but better peer relationships and better emotional well-being compared to the general population.

Read the full article: “Functional impact of congenital hand differences: Early results from the Congenital Upper Limb Differences (CoULD) Registry“

Purpose: It’s important for the study teams across the country to have a common language to diagnose congenital hand conditions. The purpose of this study was to determine if using the Oberg-Manske-Tonkin (OMT) Classification system would allow CoULD doctors to reliably diagnose the broad spectrum of hand diagnoses included in the study.

Findings: The first research paper from the CoULD Registry showed that hand surgeons from across the country can agree upon the classification of congenital hand differences using this new web-based system.

Read the full article: “Intraobserver and interobserver reliability of the Oberg-Manske-Tonkin (OMT) classification: Establishing a registry on congenital upper limb differences“