Interphalangeal joint deviation in floating-type radial polydactyly with malalignment of the flexor pollicis longus tendon: a case report

Use of the duplication range concept for understanding morphology and predicting prognosis in thumb polydactyly

“…The premise of our study came from observations that soft tissue abnormalities may be the cause of deformities in thumb duplication. We previously reported a patient with IP joint deviation and proximal phalangeal asymmetry, despite having a very hypoplastic type of thumb duplication (Saito and Morimoto, 2021). We subsequently found a malalignment of the FPL tendon and in this case, both the deviation and phalangeal deformity were corrected by centralization of the tendon.…”

“…Such variations are not negligible; for example, the asymmetric morphology of the nail and pulp is likely to influence postoperative cosmesis (Goldfarb et al., 2008; Tien et al., 2007). Skeletal morphological abnormalities are prognostic factors for postoperative deformation, such as severely deviated joints in Wassel Type IV thumb polydactyly (Hong et al., 2021; Kim et al., 2017; Lee et al., 2013; Luangjarmekorn et al., 2021) and asymmetric morphology of phalanges (Saito and Morimoto, 2021). The presence of hypoplastic elements is also important; even a well-developed ulnar thumb with a very hypoplastic ‘floating’ radial thumb has the potential to cause joint deviation (Hanaka et al., 2021; Lourie et al., 1995; Saito et al., 2018).…”

Complications after radial polydactyly surgery: analysis, prevention and management

“…In the past, simply removing the lesser developed thumb resulted in a revision rate in the range of 38%–56% on long-term follow-up, mostly because of deviation and instability (Ganley and Lubahn, 1995; Miura, 1982; Townsend et al., 1994) (Figure 4). The exception to this is the removal of a floating extra thumb but even in these cases, care must be taken to ensure there are no abnormal tendinous connections (Saito and Morimoto, 2021). Careful scrutiny of the results after excision of the lesser developed thumbs have resulted in alterations to techniques in many centres to try to decrease the revision rate by correction osteotomies, releasing connections of tendons or asymmetric insertions, stabilizing joints and a more detailed intraoperative inspection for other anatomical anomalies.…”