An Alternative Treatment Option for Blauth III B Thumb Hypoplasia-Thumb Stabilization with Iliac Crest Bone Graft and Intermetacarpal Arthrodesis

Thumb hypoplasia modified Blauth III B is usually treated by pollicization or, less commonly, by toe transfer. Both procedures always result in the resection of a body part, but with good cosmesis and acceptable function. We describe an intermetacarpal I/II arthrodesis with autologous bone graft augmentation to lengthen and stabilize the loose thumb. Clinical data were collected from nine patients, median age at surgery 3 years 8 months, with more than 7 years of follow-up. The results showed a grip strength on the Jamar dynamometer of approximately 61% of the unoperated hand. The Quick-DASH score was 11. The reconstructed thumb was 0.8 cm thinner and 1.9 cm shorter. Overall satisfaction on the VAS, with an average of 1.5 out of 10, is excellent with a partially usable thumb on a hand with five rays. The described procedure is a reliable treatment option with satisfactory results. In addition, none of the patients lost pincer grip between the second and third digit, but their thumb gained new function. Especially in environments where physical integrity has a high value, thumb construction instead of replacement could be considered.

Defining Features of Hand Anomalies in Severe Thumb Hypoplasia: A Classification Modification

PURPOSE

To investigate morphologic hand anomalies in children with severe but unclassifiable forms of thumb hypoplasia and radial-sided hand deficiency.

METHODS

We identified 15 extremities in 13 patients with severe thumb hypoplasia and associated absent radial-sided digits through the Congenital Upper Limb Differences registry. All patients had forearm involvement. Medical records, clinical photographs, and radiographs were evaluated. Radial longitudinal deficiency (RLD) and thumb hypoplasia were classified according to the Bayne and Klug classification and modified Blauth classification, respectively. Unusual or defining associated hand characteristics were identified and categorized.

RESULTS

The most common type of forearm abnormality was absence of the radius (Bayne and Klug type IV), which was present in 10 extremities in the cohort. All 15 extremities had absent thumbs with loss of additional digits. In 6 patients, RLD was part of a syndrome (46%).

CONCLUSIONS

Severe forms of thumb hypoplasia in RLD are uncommon. We propose a further modification of the Blauth classification of thumb hypoplasia, type VI, for improved communication regarding this severe type of radial deficiency involving the hand.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic IV.

Revisiting the management of Manske Type 3B and 4 thumb hypoplasia

The traditional management of Manske 3B and 4 thumbs is index finger pollicization. Recently, the transfer of composite tissues from the foot to reconstruct the thumb or the carpometacarpal joint has allowed the preservation of a five-digit hand. Concerns remained about the donor site and also the limited functional and cosmetic outcomes that could be achieved. This article challenges the existing dogma in the management of hypoplastic thumbs, that pollicization should always be the reference standard. We describe the evolution of techniques with free vascularized metatarsal transfer, our refinements and our proposal for a new classification system that accommodates these modifications. With increased experience, acceptable outcomes that are comparable with pollicization can be achieved.

On the classification of congenital thumb hypoplasia

In 1937, Müller introduced the concept of a teratological sequence of thumb hypoplasia with increasing severity from mild deficiency, through severe deficiency, to thumb absence. Blauth subsequently detailed five specific grades. In 1992, Manske and McCarroll altered Blauth's classification such that Grade 3 was sub-divided into Grades 3A and 3B, according to a presence or absence of the proximal metacarpal. Buck-Gramcko added a Grade 3C in which there was only a remnant metacarpal head. This article investigates their publications and those of others to identify 'who said what' and clarify the definitions of grades of thumb hypoplasia. A modification of Blauth's classification is proposed, which retains the integrity of the concept of Müller and the skeletal and soft tissue grading of Blauth, but which also incorporates the disparate anomalies that may present in Grades 2 and 3 hypoplastic thumbs.