Congenital Pseudarthrosis of Index Metacarpal Bone Treated with Distraction Osteogenesis Followed by Autologous Grafting.

The term “congenital pseudoarthrosis” refers to the semblance of a false joint formation which is present from birth. The soft tissue at the pseudoarthrotic site is composed of a variable admixture of fibrous tissue, fibrocartilage, and hyaline cartilage with evidence of enchondral ossification. Spaces and clefts are lined by a synovial-like tissue [1]. Congenital pseudoarthrosis is mostly seen in the lower extremity, particularly involving the tibia, fibula and femur [2]. In upper extremities, it may also involve clavicle and one or both bones of the forearm [3, 4]. However, metacarpal bone involvement is exceedingly rare with only three previous case reports in current literature [5–7]. But, to the best of our knowledge, there have been two cases of bilateral congenital pseudarthrosis of index metacarpals reported in literature up to date [5, 6]. Congenital pseudoarthrosis is usually associated with genetic syndromes and presented as a component of several other abnormalities [2]. In 1950, Aegerter suggested a possible relationship between neurofibromatosis, congenital pseudarthrosis, and fibrous dysplasia [8]. In 1949, Moore stated that “the treatment of congenital pseudarthrosis will probably never be entirely effective until the etiology has been determined. Osteosynthesis by bone-grafting still offers the principal means of attacking the problem” [9]. The treatment of congenital pseudoarthrosis is challanging because achieving complete union of pseudoarthrosis site, providing an acceptable alignment and functional extremity is difficult and refracture rate is high. This is probably due to low osteogenic capacity of the affected whole segment. The principle of the treatment is complete resection of the pseudoarthrosis, grafting the bone defect and ensure bony union either with internal or external fixation. Currently Ilizarov external fixation has gained wide acceptance as a gold standard treatment for the management of congenital tibial pseudoarthrosis [2]. Herein, we intend to present a rare case of bilateral congenital pseudoarthrosis involving bilateral index metacarpal bones. This is not a unique case and previously two other cases has been published. But what makes our case different than previous cases is the treatment of choice. We have treated this patient with excision of the pseudoarthrosis, gradual distraction to overcome the short metacarpal length without neurovascular compromise, followed by tricortical grafting and internal fixation.